US20030214898A1 - Optical pickup device and optical disk drive using the same - Google Patents

Abstract

An optical pickup device includes a light source unit an optical system which leads a return light beam to a predetermined light-receiving location and includes an object lens focusing each light beam from the light source unit to a recording surface of a corresponding storage medium and a photodetector arranged at the light-receiving location. The light source unit includes a plurality of light sources outputting light beams respectively, the plurality of light sources being arranged in proximity to each other, and a divergence-angle changing unit changing an angle of divergence of a light beam output from at least one of the plurality of light sources.

Description

BACKGROUND OF THE INVENTION
• 1. Field of the Invention[0001]
• The present invention relates to an optical pickup device and an optical disk drive using the same. More specifically, the present invention relates to an optical pickup device for an optical disk drive which focuses a light beam to a corresponding one of two optical disks of different types for recording of information, and receives a reflected light beam from the corresponding optical disk for reproduction of information.[0002]
• 2. Description of the Related Art[0003]
• In the optical disk drive, storage media, such as optical disks, in which tracks in the spiral or concentric formation are formed in the recording surface of the optical disk, are used for recording and reproduction of information. The optical disk drive emits a light beam to the optical disk to record information in the recording surface of the optical disk, and receives a reflected light beam from the recording surface of the optical disk to reproduce the information based on the received light beam.[0004]
• The optical disk drive is usually equipped with an optical pickup device. The optical pickup device is provided for emitting a laser beam to the recording surface of an optical disk to form a small light spot thereon, and for receiving a reflected laser beam from the recording surface of the optical disk.[0005]
• The optical pickup device usually includes an object lens, an optical system and a photodetector. The optical system is provided to lead the light beam emitted by the light source, to the recording surface of the optical disk, and to lead the return light beam reflected from the recording surface of the optical disk to a predetermined light-receiving location where the photodetector is arranged.[0006]
• In response to the received light beam, the photodetector outputs the electrical signal indicating the reproduced information of data that is recorded in the optical disk. Also, the optical pickup device outputs the signal including information (servo control information) required for the position control of the optical pickup device itself and the object lens.[0007]
• In recent years, a DVD (digital versatile disk) has been generalized as a mass storage medium having a recording capacity much larger than that of a CD (compact disk).[0008]
• In order to perform recording and reproduction to CD, the laser light having the wavelength 780 nm is used. In order to perform recording and reproduction to DVD, the laser light having the wavelength 650 nm is used.[0009]
• For this reason, the optical disk drive for CD and the optical disk drive for DVD have been developed respectively as different peripheral devices of information processing devices, such as personal computer.[0010]
• With recent developments of small-sized, lightweight information processing devices, the necessity for the optical disk drive, which can access both CD and DVD, is increasing.[0011]
• In this case, in order to access both DVD and CD, the optical pickup device must be provided with a light source unit containing both the semiconductor laser (DVD light source) which outputs the laser light whose wavelength is 650 nm, and the semiconductor laser (CD light source) which outputs the laser light whose wavelength is 780 nm. Furthermore, the optical pickup device must be provided with the optical system for detecting each of the two laser beams output from the two light sources.[0012]
• However, if the optical system for 650 nm and the optical system for 780 nm are arranged individually in the optical pickup device, the problem that the size of the optical pickup device is enlarged arises.[0013]
• In the following the optical pickup device equipped with the light sources of two different wavelengths will be called the two-wavelength optical pickup device.[0014]
• For example, Japanese Patent No. 3026279 discloses a laser module for a recording/reproduction apparatus. This laser module is equipped with an LD module in which two laser components which output laser light beams having different wavelengths are integrated. In the laser module, a light-receiving component is commonized to receive both the return light beams of the different wavelengths.[0015]
• According to the optical pickup device using the laser module, the commonization of the optical system and the reduction of the number of the optical parts needed are possible, and simplification of the assembly of the components, the reduction in cost, and the miniaturization of the device are promoted.[0016]
• FIG. 17 shows a relationship between the intensity distribution of the light beam output from the semiconductor laser and the location of the activation layer thereof.[0017]
• Generally, the light beam (the outgoing light beam) output from the semiconductor laser that is used as a light source is a divergent light beam with the intensity distribution in the form of an ellipse having the major axis whose direction accords with the direction perpendicular to the surface of the activation layer (hetero-junction plane) AL of the semiconductor laser LD, as shown in FIG. 17.[0018]
• The rate of the light beam received by the object lens and focused on the recording surface of the optical disk (which light beam is called the received light beam) over the outgoing light beam of the light source is represented by the ratio of the minimum optical intensity in the received light beam to the optical intensity in the center of the outgoing light beam. This ratio is called the rim intensity (RIM).[0019]
• FIG. 18 shows an example of the intensity distribution of the received light beam in the case of RIM=50%.[0020]
• FIG. 19 shows a relationship between the optical efficiency and the rim intensity of the light beam output from the semiconductor laser. The optical efficiency, which is indicated by the ratio of the quantity of light on the optical disk recording surface to the quantity of light in the outgoing light beam, is almost in the inverse proportion with the RIM, as shown in FIG. 19.[0021]
• If the optical pickup device is designed to raise the RIM, the optical efficiency will fall. If the optical pickup device is designed to raise the optical efficiency, the RIM will become low.[0022]
• Usually, the optical pickup device is designed so that the RIM to the outgoing light beam of CD light source is lower than the RIM to the outgoing light beam of DVD light source.[0023]
• This is because it is necessary to control accurately the diameter of a light spot on the recording surface of DVD, as the recording density of DVD is higher than that of CD. On the other hand, importance is attached to raising the optical efficiency for CD light source.[0024]
• However, in the optical pickup device using the laser module of Japanese Patent No. 3026279, the RIM to the outgoing light beam of CD light source and the RIM to the outgoing light beam of DVD light source become almost equal.[0025]
• When the optical system is optimized to DVD, the optical efficiency of CD light source falls, and it is difficult to deal with improvement in the access speed for the optical disk. On the other hand, when the optical system is optimized to CD, the problem arises that it is difficult to control accurately the diameter of a light spot on the recording surface of DVD.[0026]
SUMMARY OF THE INVENTION
• An object of the present invention is to provide an improved optical pickup device in which the above-described problems are eliminated.[0027]
• Another object of the present invention is to provide a light source unit of an optical pickup device that is capable of optimizing the respective intensity distributions of the light beams output from the plurality of light sources.[0028]
• Another object of the present invention is to provide a light source unit package of an optical pickup device which is capable of optimizing the respective intensity distributions of the light beams from the plurality of light source without causing enlargement and high cost, and which stably receives the return light beam from the outside.[0029]
• Another object of the present invention is to provide an optical element of an optical pickup device that is capable of adjusting the intensity distributions of two incoming light beams with sufficient accuracy.[0030]
• Another object of the present invention is to provide an optical pickup device that can respond to each of two kinds of optical disks and forms the optimal light spot for each optical disk without causing enlargement and high cost.[0031]
• Another object of the present invention is to provide an optical disk drive that includes an optical pickup device and can respond to each of two kinds of optical disks and stably carry out high-speed access to each optical disk.[0032]
• Another object of the present invention are to provide a method of manufacture of an optical pickup device in which a deviation of the outgoing direction of each of the light beams output from the plurality of light sources can be corrected with sufficient accuracy.[0033]
• The above-mentioned objects of the present invention are achieved by a light source unit comprising: a plurality of light sources outputting light beams respectively, the plurality of light sources being arranged in proximity to each other; and a divergence-angle changing unit changing an angle of divergence of a light beam output from at least one of the plurality of light sources.[0034]
• The above-mentioned objects of the present invention are also achieved by a light source unit package including a light source unit, a branch optical element reflecting a light beam, incident to the light source unit, in a predetermined direction, and a photodetector receiving the reflected light beam from the branch optical element, wherein the light source unit, the branch optical element and the photodetector are unified, and the light source unit comprising: a plurality of light sources outputting light beams respectively, the plurality of light sources being arranged in proximity to each other; and a divergence-angle changing unit changing an angle of divergence of a light beam output from at least one of the plurality of light sources.[0035]
• The above-mentioned objects of the present invention are also achieved by an optical pickup device which focuses a light beam on a recording surface of a corresponding one of two or more storage media of different types and receives a return light beam from the recording surface, the optical pickup device comprising: a light source unit; an optical system which leads the return light beam to a predetermined light-receiving location and includes an object lens focusing each light beam from the light source unit to the recording surface of the corresponding storage medium; and a photodetector arranged at the light-receiving location, the light source unit comprising: a plurality of light sources outputting light beams respectively, the plurality of light sources being arranged in proximity to each other; and a divergence-angle changing unit changing an angle of divergence of a light beam output from at least one of the plurality of light sources.[0036]
• The above-mentioned objects of the present invention are also achieved by an optical disk drive which performs recording, reproduction and erasing of information with a corresponding one of two or more optical disks of different types, the optical disk drive including: an optical pickup device and a reproduction signal processing unit performing reproduction of information based on a signal output by the optical pickup device, the optical pickup device focusing a light beam on a recording surface of the corresponding optical disk and receiving a return light beam from the recording surface, the optical pickup device comprising: a light source unit; an optical system which leads the return light beam to a predetermined light-receiving location and includes an object lens focusing each light beam from the light source unit to the recording surface of the corresponding storage medium; and a photodetector arranged at the light-receiving location, the light source unit comprising: a plurality of light sources outputting light beams respectively, the plurality of light sources being arranged in proximity to each other; and a divergence-angle changing unit changing an angle of divergence of a light beam output from at least one of the plurality of light sources.[0037]
• According to the light source unit of the present invention, the angle of divergence of the light beam output from at least one of the plurality of light sources is changed by the changing unit. For example, when the angle of divergence of the light beam output from the light source has shifted from a desired angle of divergence, it can be adjusted to the desired angle of divergence by the changing unit. Therefore, it is possible to optimize the respective intensity distributions of the light beams output from the light sources.[0038]
• Since the light source unit, the branch optical element, and the photodetector are unified, while acting as the outgoing light beam by which the intensity distribution is optimized according to the light source unit package of the present invention, without causing enlargement and high cost, it is possible to be stably receive the return light beam from the outside.[0039]
• By arranging each light source corresponding to the positional relation between the first lens portion and the second lens portion for use in the light source unit in which the two light sources are arranged in proximity to each other according to the optical element of the present invention, the angle of divergence of the light beam which acts as the outgoing light beam from one light source can be changed in the first lens portion, and the angle of divergence of the light beam which acted as the outgoing light beam from the other light source can be changed in the second lens portion.[0040]
• Since the first lens portion and the second lens portion are unified, even if the assembly process and the adjustment process are simplified, it is possible to change with sufficient accuracy the angle of divergence of the light beam output from each light source.[0041]
• Since the respective intensity distributions of the light beams output from the plurality of light sources can be optimized by using the light source unit of the present invention, the optical pickup device of the present invention makes it possible to respond to two or more kinds of optical disks, and makes it possible to form the optimal light spot on the recording surface of each optical disk.[0042]
• According to the optical disk drive of the present invention, it is possible to form the optimal light spot on the recording surface of each of the two kinds of optical disks by using the optical pickup device of the present invention. Therefore, the optical disk drive of the present invention responds to each of the two kinds of optical disks, and it is possible to stably carry out the high-speed access to each optical disk.[0043]
BRIEF DESCRIPTION OF THE DRAWINGS
• Other objects, features and advantages of the present invention will be apparent from the following detailed description when read in conjunction with the accompanying drawings.[0044]
• FIG. 1 is a block diagram of the optical disk drive in one preferred embodiment of the present invention.[0045]
• FIG. 2 is a diagram showing the composition of the optical system in the optical pickup device of FIG. 1.[0046]
• FIG. 3 is a diagram showing the composition of the optical module of FIG. 2.[0047]
• FIG. 4 is a diagram for explaining the configuration of the light beam output from each of the semiconductor lasers.[0048]
• FIG. 5A and FIG. 5B are diagrams for explaining the angle of divergence of the light beam output from the first semiconductor laser.[0049]
• FIG. 6A is a diagram for explaining the rim intensity of the light beam output from the first semiconductor laser and received by the object lens when the angle of divergence is not changed.[0050]
• FIG. 6B is a diagram for explaining the rim intensity of the light beam output from the second semiconductor laser and received by the object lens when the angle of divergence is not changed.[0051]
• FIG. 7 is a diagram for explaining an example in which the cylindrical lens is used as the optical element.[0052]
• FIG. 8A is a diagram for explaining an example in which the angle of divergence of the light beam output from the first semiconductor laser is enlarged using the cylindrical lens.[0053]
• FIG. 8B is a diagram for explaining an example in which the angle of divergence of the light beam output from the second semiconductor laser is reduced using the cylindrical lens.[0054]
• FIG. 9 is a diagram for explaining an example in which two cylindrical lenses are united.[0055]
• FIG. 10 is a diagram for explaining an example in which a mark for positioning is added to each of the semiconductor laser and the cylindrical lenses.[0056]
• FIG. 11A and FIG. 11B are diagrams for explaining an example in which the outgoing direction of the light beam with the maximum intensity is changed by the optical element.[0057]
• FIG. 12A and FIG. 12B are diagrams for explaining the overlapping range of the light beam output from the first semiconductor laser and the light beam output from the second semiconductor laser.[0058]
• FIG. 13 is a diagram for explaining the arrangement of the optimal location of the optical element.[0059]
• FIG. 14 is a diagram for explaining the relationship between the radius of curvature of the optical element and the distance z when the angle of divergence is doubled.[0060]
• FIG. 15 is a diagram for explaining an example in which the return light beam passes through a part of the optical element.[0061]
• FIG. 16 is a diagram for explaining an example in which the meniscus lens is used as the optical element.[0062]
• FIG. 17 is a diagram for explaining a relationship between the intensity distribution of the light beam output from the semiconductor laser and the location of the activation layer thereof.[0063]
• FIG. 18 is a diagram for explaining a case in which the rim intensity of the light beam output from the semiconductor laser is equal to 50%.[0064]
• FIG. 19 is a diagram for explaining a relationship between the efficiency and the rim intensity of the light beam output from the semiconductor laser.[0065]
• FIG. 20 is a block diagram of the optical disk drive in another preferred embodiment of the present invention.[0066]
• FIG. 21 is a diagram showing the composition of the optical system in the optical pickup device of FIG. 20.[0067]
• FIG. 22 is a diagram for explaining two semiconductor lasers in the light source unit of FIG. 21.[0068]
• FIG. 23 is a diagram for explaining the optical element in the light source unit of FIG. 21.[0069]
• FIG. 24 is a flowchart for explaining a method of manufacture of the optical pickup device of the preferred embodiment.[0070]
• FIG. 25A and FIG. 25B are diagrams for explaining a slide guide used to fix the photodetector at a given position.[0071]
• FIG. 26 is a diagram showing the photodetector in the optical pickup device of the preferred embodiment.[0072]
• FIG. 27 is a diagram showing the detection control device in the optical pickup device of the preferred embodiment.[0073]
• FIG. 28 is a flowchart for explaining a method of manufacture of the optical pickup device of another preferred embodiment of the present invention.[0074]
• FIG. 29A and FIG. 29B are diagrams for explaining a filter in the optical pickup device of the preferred embodiment.[0075]
• FIG. 30 is a diagram showing the detection control device in the optical pickup device of the preferred embodiment.[0076]
• FIG. 31 is a flowchart for explaining a method of manufacture of the optical pickup device of another preferred embodiment of the present invention.[0077]
• FIG. 32A and FIG. 32B are diagrams for explaining a photodetector in the optical pickup device of the preferred embodiment.[0078]
• FIG. 33 is a diagram showing the detection control device in the optical pickup device of the preferred embodiment.[0079]
• FIG. 34 is a block diagram of the optical disk drive in another preferred embodiment of the present invention.[0080]
• FIG. 35A and FIG. 35B are diagrams showing the composition of the optical pickup device of FIG. 34.[0081]
• FIG. 36 is a diagram for explaining the configuration of light beams output from the first semiconductor laser and the second semiconductor laser.[0082]
• FIG. 37A and FIG. 37B are diagrams for explaining the angle of divergence of the light beam output from the first semiconductor laser.[0083]
• FIG. 38A and FIG. 38B are diagrams for explaining the angle of divergence of the light beam output from the second semiconductor laser.[0084]
• FIG. 39 is a diagram for explaining the diameter of the light beam passing through the coupling lens.[0085]
• FIG. 40 is a diagram for explaining the relationship between the divergence angle and the rim intensity of the light beam incident to the coupling lens.[0086]
• FIG. 41A and FIG. 41B are diagrams for explaining the rim intensity of the light beam received by the object lens when the angle of divergence is not adjusted.[0087]
• FIG. 42A and FIG. 42B are diagrams for explaining the adjustment of the divergence angle by the adjustment optical element.[0088]
• FIG. 43A and FIG. 43B are diagrams for explaining the adjustment of the divergence angle by the adjustment lens element.[0089]
• FIG. 44 is a diagram showing the composition of the optical module in which the first lens and the second lens are incorporated.[0090]
• FIG. 45 is a diagram showing the composition of the optical pickup device in another preferred embodiment of the present invention.[0091]
• FIG. 46A and FIG. 46B are diagrams for explaining the adjustment of the divergence angle by the third adjustment optical element.[0092]
• FIG. 47 is a block diagram of the optical disk drive in another preferred embodiment of the present invention.[0093]
• FIG. 48 is a diagram showing the composition of the optical system of the optical pickup device of FIG. 47.[0094]
• FIG. 49A and FIG. 49B are diagrams for explaining the configuration of the light beam output from each of the semiconductor lasers.[0095]
• FIG. 50 is a diagram showing the composition of the wavelength filter.[0096]
• FIG. 51A and FIG. 51B are diagrams for explaining the rim intensity of each of the light beams received by the object lens when the micro lens is not used.[0097]
• FIG. 52 is a diagram for explaining the rim intensity of the light beam received by the object lens when the micro lens is used.[0098]
• FIG. 53 is a block diagram of the optical disk drive in another preferred embodiment of the present invention.[0099]
• FIG. 54A and FIG. 54B are diagrams for explaining the rim intensity of each of the light beams received by the object lens when the micro lens is not used.[0100]
• FIG. 55 is a diagram for explaining the rim intensity of the light beam received by the object lens when the micro lens is used.[0101]
• FIG. 56 is a block diagram of the optical disk drive in another preferred embodiment of the present invention.[0102]
• FIG. 57A and FIG. 57B are diagrams showing variations of the optical module.[0103]
• FIG. 58 is a diagram showing a variation of the optical module including three light sources.[0104]
• FIG. 59A, FIG. 59B and FIG. 59C are diagrams for explaining the composition of the micro lens and the transparent substrate.[0105]
• FIG. 60A and FIG. 60B are diagrams for explaining the deviation of the locations of the emission points of the semiconductor lasers.[0106]
• FIG. 61A and FIG. 61B are diagrams for explaining the composition of the micro lens and the transparent substrate.[0107]
• FIG. 62A, FIG. 62B and FIG. 62C are diagrams for explaining the anamorphic lens that adjusts the angle of divergence of the light beam output from the second semiconductor laser.[0108]
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
• A description will now be provided of the preferred embodiments of the present invention with reference to the accompanying drawings.[0109]
• FIG. 1 shows the composition of an[0110]optical disk drive20 in one preferred embodiment of the present invention in which the optical pickup device of the present invention is included.
• The[0111]optical disk drive20 shown in FIG. 1 comprises a spindle motor (SP/MOTOR)22 for carrying out a rotation drive of theoptical disk15, an optical pickup device (OPD)23, a laser control circuit (LASER CNTR)24, an encoder (ENCODER)25, a motor driver (DRIVER)27, a reproduction signal processing circuit (RSPC)28, a servo controller (SERVO CNTR)33, a buffer RAM (BUFFER)34, a buffer manager (BUF/MNG)37, an interface (INTERFACE)38, aROM39, aCPU40, and aRAM41.
• The[0112]optical pickup device23 is provided for receiving the return light from the recording surface of theoptical disk15, and for emitting laser light to the recording surface of theoptical disk15 in which the tracks in the spiral or concentric formation are formed.
• Referring to FIG. 1, the reproduction[0113]signal processing circuit28 converts into an electrical voltage signal the current signal which is the output signal of theoptical pickup device23, and detects the wobble signal, the reproduction signal and the servo signal (the focal error signal, the track error signal) based on the voltage signal.
• In the reproduction[0114]signal processing circuit28, the address information, the synchronizing signal, etc. are extracted from the wobble signal.
• The extracted address information is outputted to the[0115]CPU40, and the synchronizing signal is outputted to theencoder25.
• After the reproduction[0116]signal processing circuit28 performs error-correction processing to the reproduction signal, it is stored in thebuffer RAM34 through thebuffer manager37.
• The servo signal is outputted to the[0117]servo controller33 from the reproductionsignal processing circuit28.
• The[0118]servo controller33 generates the control signal which controls theoptical pickup device23 based on the servo signal, and outputs it to themotor driver27.
• The[0119]buffer manager37 notifies to theCPU40 when the I/O of the data to thebuffer RAM34 is managed and the accumulated amount of data becomes the predetermined value.
• The[0120]motor driver27 controls theoptical pickup device23 and thespindle motor22 based on the directions of the control signals from theservo controller33 and theCPU40.
• The[0121]encoder25 takes out the data accumulated at thebuffer RAM34 through thebuffer manager37 based on directions of theCPU40, adds the error correction code, and creates the write-in data to theoptical disk15.
• The[0122]encoder25 outputs write-in data to thelaser control circuit24 synchronizing with the synchronizing signal from the reproductionsignal processing circuit28 based on the directions from theCPU40.
• The[0123]laser control circuit24 controls the laser light output from theoptical pickup device23 based on the write-in data from theencoder25.
• The[0124]laser control circuit24 controls one side of the two light sources of theoptical pickup device23 later mentioned based on directions of theCPU40.
• The[0125]interface38 is the bi-directional communication interface with the host system (for example, personal computer), and is based on the standard interfaces, such as ATAPI (AT Attachment Packet Interface) and SCSI (Small Computer System Interface).
• The program described in code decipherable by the[0126]CPU40 is stored in theROM39.
• The[0127]CPU40 temporarily stores data required for control etc. in theRAM41 while controlling operation of each part of the above according to the above-mentioned program stored in theROM39.
• Next, the composition of the[0128]optical pickup device23 will be described with reference to FIG. 2 and FIG. 3.
• The[0129]optical pickup device23 outputs the laser light whose wavelength is 650 nm or the laser light whose wavelength is 780 nm alternatively, as shown in FIG. 2.
• The[0130]optical pickup device23 contains the optical module LM, thecoupling lens52, the quarter-wave plate62, theobject lens60, and the drive system (the focusing actuator, the tracking actuator, and the seeking motor) as a light source unit package which receives the return light beam from the recording surface of theoptical disk15.
• The optical module LM contains the light-emission portion EL and the light-receiving portion RL as a light source unit, as shown in FIG. 3.[0131]
• The light-emission portion EL contains the first[0132]optical element55 which changes the angle of divergence of the light beam output from thefirst semiconductor laser53 which outputs the laser light the wavelength of which is 650 nm, thesecond semiconductor laser54 which outputs the laser light the wavelength of which is 780 nm, and thefirst semiconductor laser53, and the secondoptical element56 which changes the angle of divergence of the light beam output from thesecond semiconductor laser54.
• The light-receiving portion RL comprises the light-receiving[0133]component59 as a photodetector which receives the light beam which branched by thepolarization hologram61 and thepolarization hologram61 as a branch optical element which branch the received light from the recording surface of theoptical disk15.
• The[0134]first semiconductor laser53 is chosen when theoptical disk15 is DVD, and thesecond semiconductor laser54 is chosen when theoptical disk15 is CD.
• In this preferred embodiment, as shown in FIG. 4, the[0135]first semiconductor laser53 and thesecond semiconductor laser54 are arranged so that the activation layers AL1 and AL2 may become parallel to XZ plane.
• Therefore, the light beam output from each semiconductor laser is divergence light with the intensity distribution of the ellipse form which makes Y-axis direction the direction of the transverse.[0136]
• The light beam of angle-of-divergence θ1Y in YZ plane and angle-of-divergence θ1Z in XZ plane output from the[0137]first semiconductor laser53 has the relation of θ1Y>θ1Z, rather than is the same, as shown in FIG. SA and FIG. 5B.
• Similarly, the light beam of the angle of divergence (referred to as θ2Y) in YZ plane and the angle of divergence (referred to as θ2Z) in XZ plane output from the[0138]second semiconductor laser54 also has the relation of θ2Y>θ2Z, rather than is the same.
• In this preferred embodiment, to the light beam output from the[0139]first semiconductor laser53, the angle of divergence is changed using the firstoptical element55 so that RIM may become about 30% (optical efficiency=about 45%), and to the light beam taken out from thesecond semiconductor laser54, the angle of divergence is changed using the secondoptical element56 so that RIM may become about 15% (optical efficiency=about 50%).
• The light beam Bdvd received by the[0140]object lens60 among the light beams output from thefirst semiconductor laser53 when there is no firstoptical element55, as shown in FIG. 6A, and it is RIM=30% about the Y axis direction and it is RIM<30% about the X axis direction.
• Moreover, the light beam Bcd incorporated by the[0141]object lens60 among the light beams which are output from thesecond semiconductor laser54 when there is no secondoptical element56, as shown in FIG. 6B, and it is RIM=15% about the X axis direction, and it is RIM>15% about the Y axis direction.
• In order to double the angle of divergence θ1Z within XZ plane of the light beam output from the first semiconductor laser[0142]53 (θ1Y/θ1Z) (>1) and to change the angle of divergence, as shown in FIG. 7, the cylindrical lens (the first cylindrical lens) is used as the firstoptical element55.
• A description of the first cylindrical-[0143]lens55a(this cylindrical lens) will now be given.
• The first cylindrical-[0144]lens55ais arranged on the optical path length of the light beam output from thefirst semiconductor laser53 so that the cylinder axis orientation may be in agreement with Y-axis direction.
• As shown in FIG. 8A, the angle of divergence of the light beam through first cylindrical-[0145]lens55abecomes larger than angle-of-divergence θ1Z within XZ plane of the light beam output from thefirst semiconductor laser53, and becomes almost equal to angle-of-divergence θ1Y within YZ plane.
• The light beam received by the[0146]object lens60 becomes RIM=30% mostly also about X-axis direction.
• Moreover, in order to double angle-of-divergence θ2Y within YZ plane of the light beam output from the second semiconductor laser[0147]54 (θ2Z/θ2Y) (<1) and to change the angle of divergence, as shown in FIG. 7, the cylindrical lens (the second cylindrical lens) is used as the secondoptical element56.
• A description of the second cylindrical-[0148]lens56a(this cylindrical lens) will now be given.
• The second cylindrical-[0149]lens56ais arranged on the optical path length of the light beam output from thesecond semiconductor laser54 so that the cylinder axis orientation may be in agreement with X axis direction.
• As shown in FIG. 8B, the angle of divergence of the light beam through second cylindrical-[0150]lens56abecomes smaller than angle-of-divergence θ2Y within YZ plane of the light beam output from thesecond semiconductor laser54, and becomes almost equal to angle-of-divergence θ2Z within XZ plane.
• The light beam incorporated by the[0151]object lens60 becomes RIM=15% mostly also about Y-axis direction.
• To the polarization direction (for example, P polarization) of the light beam output from each semiconductor laser, the[0152]polarization hologram61 has the low diffraction efficiency, and it is set up so that the diffraction efficiency may become high to the polarization direction (for example, S polarization) of the return light beam.
• Therefore, in the[0153]polarization hologram61, about 95% of the light beam which came out of each semiconductor laser and is put is penetrated, and about 35% of the return light beam diffracts
• The[0154]photodetector59 contains two or more light-receiving components which output the optimal signal for detecting the wobble signal, the reproduction signal, the servo signal, etc.
• The action of the above-mentioned[0155]optical pickup device23 is explained.
• First, the case where the[0156]optical disk15 is DVD will be explained.
• The angle of divergence in XZ plane is expanded in first cylindrical-[0157]lens55a, and the light beam of the linear polarization (for example, P polarization) output from thefirst semiconductor laser53 is incident to thepolarization hologram61.
• After most light beams incident to the[0158]polarization hologram61 penetrate thepolarization hologram61 and it serves as parallel light with thecoupling lens52, it is made into the circularly polarized light with the quarter-wave plate62, and is focused on the recording surface of theoptical disk15 as a minute spot through theobject lens60.
• With the outward trip, the received light (return light beam) reflected in respect of record of the[0159]optical disk15 turns into the circularly polarized light of the circumference of the contrary, is again made into parallel light with theobject lens60, and let it be the linear polarization (for example, S polarization) which intersected perpendicularly with the outward trip with the quarter-wave plate62.
• The light beam through the[0160]collimator lens52 is incident to thepolarization hologram61.
• The return light beam which carried out incidence to the[0161]polarization hologram61 is diffracted, and is received by thephotodetector59.
• With each light-receiving component which constitutes the[0162]photodetector59, the current signal according to the amount of the received light is outputted to the reproductionsignal processing circuit28, respectively.
• Next, the case where the[0163]optical disk15 is CD will be explained.
• The angle of divergence in YZ plane is reduced in second cylindrical-[0164]lens56a, and the light beam of the linear polarization (for example, P polarization) output from thesecond semiconductor laser54 is incident to thepolarization hologram61.
• After each light beam through the[0165]polarization hologram61 is converted into the parallel light beam by thecoupling lens52, it is converted into the circularly polarized light with the quarter-wave plate62, and is focused on the recording surface of theoptical disk15 as a minute light spot through theobject lens60.
• With the outward trip, the received light (return light beam) reflected in respect of record of the[0166]optical disk15 turns into the circularly polarized light of the circumference of the contrary, is again made into parallel light with theobject lens60, and let it be the linear polarization (for example, S polarization) which intersected perpendicularly with the outward trip with the quarter-wave plate62.
• The light beam through the[0167]collimator lens52 is incident to thepolarization hologram61.
• The return light beam incident to the[0168]polarization hologram61 is diffracted, and is received by thephotodetector59.
• With each light-receiving component which constitutes the[0169]photodetector59, the current signal according to the amount of the received light is outputted to the reproductionsignal processing circuit28, respectively.
• It can be distinguished from the intensity of the received light from the recording surface whether the[0170]optical disk15 is CD or DVD.
• Usually, this distinction is performed at the time of loading, when the[0171]optical disk15 is intercalated in the predetermined location of theoptical disk drive20.
• It is also possible to distinguish the kind of[0172]optical disk15 based on TOC (Table Of Contents) information, PMA (Program Memory Area) information, the wobble signal, etc. which are beforehand recorded on theoptical disk15.
• The distinction result is notified to the[0173]laser control circuit24, and either thefirst semiconductor laser53 and thesecond semiconductor laser54 are chosen by thelaser control circuit24.
• Next, processing operation in the case of recording data on the[0174]optical disk15 is briefly explained using theoptical disk drive20.
• In addition, selection of the semiconductor laser shall be carried out as described above, and shall already have been performed.[0175]
• The[0176]CPU40 notifies the information that the record request is received from the host system to the reproductionsignal processing circuit28 while outputting the control signal for controlling rotation of thespindle motor22 based on the record rate to themotor driver27, if the record request is received from the host system.
• If rotation of the[0177]optical disk15 reaches the predetermined linear velocity, in the reproductionsignal processing circuit28, address information will be acquired based on the output signal from theoptical pickup device23, and it will notify to theCPU40.
• Based on the output signal from the[0178]optical pickup device23, the reproductionsignal processing circuit28 detects the track error signal and the focal error signal, and outputs them to theservo controller33.
• The[0179]servo controller33 drives the tracking actuator and the focusing actuator of theoptical pickup device23 through themotor driver27 based on the track error signal and the focus error signal from the reproductionsignal processing circuit28.
• That is, the tracking error and the focusing error are corrected.[0180]
• The[0181]CPU40 accumulates the data from the host system to thebuffer RAM34 through thebuffer manager37.
• If the amount of data accumulated at the[0182]buffer RAM34 exceeds the predetermined value, thebuffer manager37 will notify to theCPU40.
• The[0183]CPU40 outputs the specified signal which directs the seeking operation of theoptical pickup23 that it writes in and theoptical pickup23 is located in the start point to themotor driver27 based on the address information from the reproductionsignal processing circuit28 while it is written in theencoder25 and directs creation of data, if the notice from thebuffer manager37 is received.
• If the[0184]CPU40 determines that the location of theoptical pickup device23 writes in and it is the start point based on the address information from the reproductionsignal processing circuit28, it will be notified to theencoder25.
• The[0185]encoder25 records write-in data on theoptical disk15 through thelaser control circuit24 and theoptical pickup device23.
• Next, processing operation in the case of reproducing the data currently recorded on the[0186]optical disk15 using theoptical disk drive20 mentioned above is explained.
• Selection of the semiconductor laser shall be carried out as described above, and shall already have been performed.[0187]
• The[0188]CPU40 will output the control signal for controlling rotation of thespindle motor22 based on the reproduction rate to themotor driver27, if the reproduction request is received from the host system.
• The[0189]CPU40 notifies the purport that the reproduction request is received from the host to the reproductionsignal processing circuit28.
• If rotation of the[0190]optical disk15 reaches the predetermined linear velocity, the reproductionsignal processing circuit28 will acquire address information based on the output signal from theoptical pickup device23, and will notify it to theCPU40.
• The tracking error and the focusing error are corrected similar to the previous embodiment mentioned above.[0191]
• The[0192]CPU40 outputs the specified signal which direct the seeking operation that it reads and theoptical pickup device23 is located in the start point to themotor driver27 based on the address information from the reproductionsignal processing circuit28.
• If the[0193]CPU40 determines it whether it is the reading start point to check, and for the location of theoptical pickup device23 to read, and to be the start point based on the address information from the reproductionsignal processing circuit28, it will be notified to the reproductionsignal processing circuit28.
• After the reproduction[0194]signal processing circuit28 detects the reproduction signal from the output signal of theoptical pickup device23 and performs error-correction processing etc., it is accumulated to thebuffer RAM34.
• The[0195]buffer manager37 transmits to the host through theinterface38, when the data accumulated at thebuffer RAM34 are assembled as sector data.
• As mentioned above, the reproduction[0196]signal processing circuit28 detects the focal error signal and the track error signal based on the output signal from theoptical pickup device23, and corrects the focusing error and the tracking error at any time through theservo controller33 and themotor driver27, until the recording processing and the regeneration are completed.
• The optical disk drive of this preferred embodiment realizes processing according to the reproduction[0197]signal processing circuit28 and the program performed by theCPU40 and theCPU40 so that clearly from the above explanation.
• However, the present invention is not limited to this preferred embodiment.[0198]
• That is, it is possible to constitute a part of the composition of that processing according to the program by the[0199]CPU40 realizes by the hardware. Or it is possible to constitute all the composition by hardware.
• As explained above, according to the light source unit of this preferred embodiment, the angle-of-divergence θ1Z within XZ plane of the light beam output from the[0200]first semiconductor laser53 is changed twice (θ1Y/θ1Z) (>1) by the first cylindrical-lens55a.
• For example, if the light source unit of this preferred embodiment is used for the optical pickup device which can respond to both DVD and CD, the light beam incorporated by the[0201]object lens60 among the light beams which are output from thefirst semiconductor laser53 will become RIM=30% mostly also about X axis direction.
• Therefore, it becomes possible to form the optimal optical spot for DVD in the recording surface.[0202]
• Moreover, according to the light source unit of this preferred embodiment, the angle-of-divergence θ2Y within YZ plane of the light beam output from the[0203]second semiconductor laser54 is changed twice (θ2Z/θ2Y) (<1) by the second cylindrical-lens56a.
• For example, if the light source unit of this preferred embodiment is used for the optical pickup device which can respond to both DVD and CD, the light beam incorporated by the[0204]object lens60 among the light beams which are output from thesecond semiconductor laser54 will become RIM=15% mostly also about Y axis direction.
• Therefore, most light beams which are output from the[0205]second semiconductor laser54 will be incorporated by theobject lens60, and it becomes possible to raise optical efficiency of it.
• It becomes possible to form the optimal optical spot for CD in the recording surface, and can respond to improvement in the speed of the access rate.[0206]
• Furthermore, according to the light source unit of this preferred embodiment, the[0207]semiconductor laser53 and54 and theoptical elements55 and56 are contained and unified in the same housing.
• For example, if the light source unit of this preferred embodiment is used for the optical pickup device, the miniaturization of the optical pickup device can be promoted.[0208]
• Moreover, since each semiconductor laser and each optical element are positioned with accuracy sufficient in the case of the unification, respectively, they can simplify the attachment process and the adjustment process.[0209]
• That is, work cost is reduced and it becomes possible to promote low cost.[0210]
• According to the light source unit package of this preferred embodiment, the[0211]photodetector59 and thepolarization hologram61 are united with the light-emission portion EL.
• For example, if the light source unit package of this preferred embodiment is used for the optical pickup device, the miniaturization of the optical pickup device can be promoted.[0212]
• Moreover, since the[0213]photodetector59 and thepolarization hologram61 are positioned with accuracy sufficient in the case of the unification, they can simplify the attachment process and the adjustment process.
• That is, work cost is reduced and it becomes possible to promote low cost.[0214]
• According to the light source unit package of this preferred embodiment, as a branch optical element, the diffraction efficiency is low to the polarization direction of the light beam output from each semiconductor laser, and the[0215]polarization hologram61 set up so that the diffraction efficiency might become high to the polarization direction of the return light beam is used.
• For example, if the light source unit package of this preferred embodiment is used for the optical pickup device, incidence of the light beam output from each semiconductor laser will be carried out to the[0216]coupling lens52, without the quantity of light almost falling.
• Therefore, high-speed access to the[0217]optical disk15 is attained.
• Moreover, since the amount of the received light in the[0218]photodetector59 increases, the signal level and the S/N ratio of the signal which are outputted from each light-receiving component which constitutes thephotodetector59 can be raised.
• Since the light beam by which incidence is carried out to the[0219]coupling lens52 has the optimal optical intensity distribution for the wave length according to the optical pickup device of this preferred embodiment, the light beam incorporated by theobject lens60 can secure the optimal RIM for the wave length.
• Therefore, without causing enlargement and high cost, it can respond to two or more kinds of information storage mediums, and the optimal optical spot for each information storage medium can be formed in the recording surface.[0220]
• According to the optical disk drive of this preferred embodiment, as for both DVD and CD, the optimal light spot can be formed in the recording surface also to each optical disk (DVD and CD), it can respond to both and it becomes possible to be stably perform the recording and reproduction of information with sufficient accuracy.[0221]
• By the miniaturization of the[0222]optical pickup device23, the miniaturization of the optical disk drive itself and reduction of the demand can also be promoted.
• For example, when used as a portable device, carrying the[0223]optical pickup device23 becomes easy and becomes usable for a long time.
• Although this preferred embodiment explained the case where each optical element is arranged individually. It is not limited to only this example. Each optical element may be unified.[0224]
• For example, as shown in FIG. 9, it is possible to use the[0225]optical element63 equipped withsecond lens portion63bwhich has the optical function equivalent to first cylindrical-lens55a,first lens portion63awhich has the equivalent optical function, and the second cylindrical-lens56a.
• That is, it can be considered that this[0226]optical element63 is what unified first cylindrical-lens55aand second cylindrical-lens56a.
• When performing positioning of[0227]first lens portion63ato thefirst semiconductor laser53, theoptical element63 is moved to X axis direction.
• Even if the[0228]second lens portion63bmoves to X axis direction simultaneously at this time, it is changeless to the optical action of thesecond lens portion63bto the light beam output from thesecond semiconductor laser54.
• Moreover, when performing positioning of[0229]second lens portion63bto thesecond semiconductor laser54, theoptical element63 is moved to Y-axis direction.
• Even if the[0230]first lens portion63amoves to Y-axis direction simultaneously at this time, it is changeless to the optical action offirst lens portion63ato the light beam output from thefirst semiconductor laser53.
• Since the direction of positioning to the semiconductor laser in[0231]first lens portion63aandsecond lens portion63blies at right angles mutually, each lens portion can be arranged in the optimal location to each semiconductor laser, without interfering mutually.
• Therefore, it becomes possible to simplify the attachment process and the adjustment process.[0232]
• That is, work cost is reduced and low cost can be promoted. It is possible to add the mark for positioning to the semiconductor laser and the optical element.[0233]
• It enables it to simplify the attachment process and the adjustment process.[0234]
• In the above-mentioned preferred embodiment, in order to carry out positioning to X axis direction to the[0235]first semiconductor laser53, as shown in FIG. 10, as for first cylindrical-lens55a, it is good to add the mark of the shape of a straight line prolonged in the direction (Y axis direction) which intersects perpendicularly with the activation layer of thefirst semiconductor laser53 to thefirst semiconductor laser53 and first cylindrical-lens55aside.
• At the attachment process, the location of the[0236]first semiconductor laser53 and first cylindrical-lens55acan be correctly doubled by making in agreement themark AM1 by the side of thefirst semiconductor laser53, and the mark AM2 by the side of first cylindrical-lens55a.
• On the other hand, in order to carry out positioning to Y axis direction to the[0237]second semiconductor laser54 as shown in FIG. 10, it is possible to add the mark to the second cylindrical-lens56aprolonged in the direction (X axis direction) parallel to the activation layer of thesecond semiconductor laser54 to the second cylindrical-lens56aside.
• At the attachment process, the location of the[0238]second semiconductor laser54 and second cylindrical-lens56acan be correctly doubled by making in agreement the activation layer of thesecond semiconductor laser54, and the mark AM3 by the side of second cylindrical-lens56a.
• Since the thickness of the activation layer in the semiconductor laser is usually about 0.2 micrometers, it can use the activation layer as a mark for positioning.[0239]
• The mark for positioning is not limited to the straight-line-like mark.[0240]
• Moreover, it is not limited to the location shown in FIG. 10 also about the location which adds the mark for positioning.[0241]
• It becomes possible to discriminate the front flesh side of the optical element by the mark for positioning.[0242]
• If there are the location gap at the time of attaching each semiconductor laser (mounting gap) and the gap of the activation layer in each semiconductor laser, the outgoing direction of the light beam output from each semiconductor laser may not be in agreement.[0243]
• If the outgoing direction of the light beam output from each semiconductor laser has shifted, since the coupling lens will be commonized, the light beam output from one of the semiconductor laser causes the optical-axis gap to the optical axis of the object lens.[0244]
• For example, as shown in FIG. 11B as shown in FIG. 11A, when the outgoing direction of the light beam output from the[0245]first semiconductor laser53 is not in agreement with Z axis direction in XZ plane in the above-mentioned preferred embodiment
• By shifting the location about X axis direction of first cylindrical-[0246]lens55a, the outgoing direction of the light beam through the first cylindrical-lens55acan be made mostly in agreement with Z-axis direction.
• This becomes possible to reduce the optical-axis gap to the optical axis of the[0247]object lens60.
• Next, the arrangement location of the[0248]optical elements55 and56 is considered.
• The light-emission point of the[0249]first semiconductor laser53 emitting light and the light-emission point of thesecond semiconductor laser54 are arranged in close proximity about the X-axis direction.
• As shown in FIG. 12A, the range (interaction region) KA with which the range through which the light beam output from the[0250]first semiconductor laser53 passes, and the range through which the light beam output from thesecond semiconductor laser54 passes lap exists near the point of each semiconductor laser emitting light.
• For example, if the first[0251]optical element55 is arranged in the location including the interaction region KA as shown in FIG. 12B, the periphery portion of the light beam which came out of thesecond semiconductor laser54, and is put will pass the firstoptical element55.
• Un-arranging, such as decline in optical efficiency, aggravation of aberration, and generating of the stray light, may arise.[0252]
• In order to make it the light beam output from the semiconductor laser other than the corresponding semiconductor laser not pass, as for each optical element, arranging to the semiconductor laser side is more desirable than the interaction region KA respectively.[0253]
• As shown in FIG. 13, the distance z from the light-emission point of the light source to an outgoing plane of the optical element in the Z-axis direction of XYZ orthogonal coordinate system with XY plane being the outgoing plane meets requirement conditions:[0254]
• d≦z≦(x−ε)/{tan(θ1/2)+tan(θ2/2)}
• where x indicates a distance in the X axis direction between the light-emission point of the[0255]light source53 and the light-emission point of the adjacentlight source54 in proximity to thelight source53, θ1 indicates an angle of divergence of the first light beam output in the Z axis direction from thelight source53, θ2 indicates an angle of divergence of the second light beam output in the Z axis direction from the adjacentlight source54, d indicates a thickness in the Z axis direction of theoptical element55, and ε indicates a width of a region in the x axis direction, the region being interposed between an optical path of the first light beam and an optical path of the second light beam, and neither the first light beam nor the second light beam passing through the region.
• The minimum value of the distance z in the Z-axis direction of the light-emission point and the outgoing surface of the[0256]optical element55 will be set to d. Therefore, what is necessary is just to make it the distance z in the Z-axis direction of the light-emission point and the outgoing side of the optical element serve as the value within the limits indicated by the above-mentioned requirement conditions.
• For example, the optical element which doubles the angle of divergence, the radius of curvature of the optical element becomes large, so that the distance z is large, as the relation between the radius of curvature and the distance z is shown in FIG. 14.[0257]
• Generally, if the radius of curvature becomes large, processing of the lens becomes easy and can lower the manufacturing cost.[0258]
• Moreover, while the allowable error in the attachment process becomes large and the dependability after attachment improves, it becomes possible to simplify the adjustment process and work cost can be lowered.[0259]
• It is desirable to use the optical element which has the greatest radius of curvature within the limits which meet the above conditions as the first[0260]optical element55 and the secondoptical element56.
• Since the light source unit package is miniaturized, although it is in the inclination which arranges the photodetector in the location close to the semiconductor laser, it is necessary to consider that the quantity of light of the return light beam does not fall.[0261]
• When the optical element is especially arranged in the front face of the point of the semiconductor laser emitting light, it returns also not only to the effective range of the optical element but to un-effective ranges, and it is necessary to make it the light beam not pass.[0262]
• Since the permeability of light is not 100% in the un-effective range, either, even if the return light beam passes through the un-effective range, it is for the amount of the received light in the photodetector to fall.[0263]
• In the above-mentioned preferred embodiment, as shown in FIG. 15, when it diffracts by the[0264]polarization hologram61, slitting and the hole are made in the un-effective range of the firstoptical element55.
• It is appropriate to make the return light beam not pass the first[0265]optical element55.
• Thus, the light source unit package can be miniaturized, without reducing the amount of the received light in the[0266]photodetector59.
• Although the above-mentioned preferred embodiment explained the case where the cylindrical lens is used as an optical element for changing the angle of divergence of the light beam output from each semiconductor laser, it is possible to use not only this but the spherical lens, the aspheric lens, the aspherical-surface cylindrical lens, the aspherical-surface cylindrical lens, etc.[0267]
• In the above-mentioned preferred embodiment, the astigmatism occurs at the same time it changes the angle of divergence, since the cylindrical lens of the first page is used.[0268]
• It is because it has the focus about the direction which intersects perpendicularly with the cylinder axis to power being 0 (focal-distance infinity) about the cylinder axis direction of the cylindrical lens.[0269]
• Therefore, what is necessary when the astigmatism poses the problem is just to use the optical element which corrects the astigmatism at the same time it changes the angle of divergence. Such an optical element is, for example, the plain-anamorphic lens, the plain-toroidal lens, the positive (negative) meniscus lens, the anamorphic-anamorphic lens, the toroidal-toroidal lens, and the toroidal-anamorphic lens.[0270]
• For example, in using the meniscus lens, as shown in FIG. 16, to the light beam output from the[0271]first semiconductor laser53, it uses positive-meniscus-lens56bto the light beam output from thesecond semiconductor laser54 using negative-meniscus-lens55b.
• While changing each angle of divergence, it becomes possible to correct the astigmatic.[0272]
• In the above-mentioned preferred embodiment, when there is no first[0273]optical element55, the RIM of Y axis direction in the light beam incorporated by theobject lens60 among the light beams output from thefirst semiconductor laser53 is about 30%.
• Alternatively, the RIM of Y-axis direction may be smaller than 30%. In such a case, as for Y axis direction and X axis direction, it is appropriate to use the optical element which enlarges both the divergence angle θ1Y in YZ plane of the light beam output from the[0274]first semiconductor laser53, and the divergence angle θ1Z in XZ plane, instead of first cylindrical-lens55a, so that it may become RIM=30%.
• Similarly, in the above-mentioned preferred embodiment, when there is no second[0275]optical element56, the RIM of X axis direction in the light beam incorporated by theobject lens60 among the light beams output from thesecond semiconductor laser54 is about 15%.
• Alternatively, the RIM of X-axis direction may be larger than 15%. In such a case, as for Y axis direction and X axis direction, it is appropriate to use the optical element which enlarges both the angle-of-divergence θ2Y in YZ plane of the light beam output from the[0276]second semiconductor laser54, and the angle-of-divergence θ2Z in XZ plane, instead of the second cylindrical-lens56a, so that it may become RIM=15%.
• The above-mentioned preferred embodiment has explained the case where the second cylindrical-[0277]lens56awhich reduces the angle of divergence of the light beam which outputs the angle of divergence of the light beam output from thefirst semiconductor laser53 from first cylindrical-lens55ato enlarge and thesecond semiconductor laser54 is used. The present invention is not limited to this example.
• When the optimal coupling lens for the light beam output from the[0278]first semiconductor laser53 is used, the first cylindrical-lens55ais unnecessary.
• In this case, since the amount of change of the angle of divergence becomes large to the light beam output from the[0279]second semiconductor laser54, it is good to use the different optical element from the second cylindrical-lens56a.
• When the optimal coupling lens for the light beam output from the[0280]second semiconductor laser54 is used, second cylindrical-lens56ais unnecessary.
• In this case, since the amount of change of the angle of divergence becomes large to the light beam output from the[0281]first semiconductor laser53, it is good to use the different optical element from first cylindrical-lens55a.
• Although the above-mentioned preferred embodiment explained the case where the wavelength of the light beam output from the light source is the two kinds, the present invention is not limited to this example.[0282]
• The above-mentioned preferred embodiment explained the case where the[0283]polarization hologram61 is used as a branch optical element for branching the return light beam in the direction of the light-receiving side of thephotodetector59.
• It is possible to use not only this but the non-polarized hologram, the beam splitter, the polarization beam splitter, etc.[0284]
• In this case, when the branch optical element does not have polarization nature, the quarter-[0285]wave plate62 is unnecessary.
• The above-mentioned preferred embodiment explained the case where the light-emission portion EL and the light-receiving portion RL are unified.[0286]
• It is possible to arrange individually not only this but also the light-emission portion EL, and the light-receiving portion RL, respectively.[0287]
• The above-mentioned preferred embodiment explained the case where it is the divergence light in which the configuration of the light beam of are outputting from the light source has the intensity distribution of the ellipse form.[0288]
• It is possible to be the divergence light in which the configuration of the light beam of are outputting not only from this but also from the light source has the almost circular intensity distribution.[0289]
• In the above-mentioned preferred embodiment, when target RIM is 30% when the[0290]optical disk15 is DVD, and theoptical disk15 is CD, the case where target RIM is 15% has been explained. The present invention is not limited to this example.
• The above-mentioned preferred embodiment explained the case where the optical module LM and the[0291]polarization hologram61 are unified. It is not necessary to unify not only this but also the optical module LM, and thepolarization hologram61.
• As explained above, according to the light source unit of the present invention, both the optical intensity distributions of the light beam output from two or more light sources can be optimized.[0292]
• While outputting the light beam by which the optical intensity distribution is optimized according to the light source unit package of the present invention, without causing enlargement and high cost, it is stabilized and the light beam from the outside can be received.[0293]
• According to the optical element of the present invention, the optical intensity distributions of the two incoming beams can be changed with sufficient accuracy.[0294]
• According to the optical pickup device of the present invention, without causing enlargement and high cost, it can respond to two or more kinds of information storage mediums, and the optimal optical spot for each information storage medium can be formed.[0295]
• According to the optical disk drive of the present invention, it can respond to two or more kinds of information storage mediums, and it is stabilized and access at the high speed can be performed.[0296]
• FIG. 20 shows the composition of the optical-disk-[0297]drive20A in one first preferred embodiment in which the optical pickup device concerning the present invention is included.
• The optical-disk-[0298]drive20A shown in FIG. 20 comprises thespindle motor22 for carrying out the rotation drive of theoptical disk15 as an information storage medium, the optical-pickup-device23A, thelaser control circuit24, theencoder25, themotor driver27, the reproductionsignal processing circuit28, theservo controller33, thebuffer RAM34, thebuffer manager37, theinterface38, theROM39, theCPU40, and theRAM41.
• The optical-pickup-[0299]device23A is provided for receiving the received light from the recording surface and for focusing the laser light on the recording surface of theoptical disk15.
• The reproduction[0300]signal processing circuit28 detects the wobble signal, the RF signal, the servo signal (the focal error signal, the track error signal), etc. based on the output signal of the optical-pickup-device23A.
• And the reproduction[0301]signal processing circuit28 extracts address information, the synchronizing signal, etc. based on the wobble signal.
• The address information extracted is outputted to the[0302]CPU40, and the synchronizing signal is outputted to theencoder25.
• Furthermore, after the reproduction[0303]signal processing circuit28 performs error-correction processing to the RF signal, it is stored in thebuffer RAM34 through thebuffer manager37.
• Moreover, the servo signal is outputted to the[0304]servo controller33 from the reproductionsignal processing circuit28.
• The[0305]servo controller33 generates the various control signals which control the optical-pickup-device23A based on the servo signal, and outputs them to themotor driver27.
• The[0306]buffer manager37 notifies I/O of the data to thebuffer RAM34 to theCPU40 that it manages and the accumulated amount of data becomes the predetermined value.
• The[0307]motor driver27 controls the optical-pickup-device23A and thespindle motor22 based on directions of the control signal from theservo controller33, and theCPU40.
• It is written in synchronizing with the synchronizing signal from the reproduction[0308]signal processing circuit28, and outputs data to thelaser control circuit24 while the above-mentionedencoder25 takes out the data accumulated at thebuffer RAM34 through thebuffer manager37 based on directions of theCPU40, performs addition of the error correction code etc. and creates the write-in data to theoptical disk15.
• The[0309]laser control circuit24 controls the output of the laser light output from the optical-pickup-device23A based on directions of the write-in data from theencoder25, and theCPU40.
• In addition, let one side of the two light sources of optical-pickup-[0310]device23A mentioned later be the control object in thelaser control circuit24 based on directions of theCPU40.
• The[0311]interface38 is the bi-directional communication interface with the host (for example, personal computer), and is based on the standard interfaces, such as ATAPI (AT Attachment Packet Interface) and SCSI (Small Computer System Interface).
• The program described in code decipherable by the[0312]CPU40 is stored in theROM39.
• And the[0313]CPU40 stores data required for control temporarily in theRAM41 while controlling operation of each part of the above according to the program stored in theROM39.
• Next, the composition of the optical-pickup-[0314]device23A will be described with respect to FIG. 21 through FIG. 23.
• The optical-pickup-[0315]device23A is equipped with thelight source unit51 as shown in FIG. 21.
• While leading the light beam output from the[0316]light source unit51 to the recording surface of theoptical disk15 including the angle-of-divergence adjustment lens70 as an adjustment optical element, thecollimator lens52, thebeam splitter54, theobject lens60, and thedetection lens58, it has the optical system which is reflected in respect of record and to which it returns and the light beam is led to the predetermined light-receiving location, thephotodetector59 arranged in the light-receiving location.
• The[0317]light source unit51, the optical system, and thephotodetector59 are attached by the position relation in the housing of the optical pickup device.
• As shown in FIG. 22, the[0318]light source unit51 is configured so that thefirst semiconductor laser51awhich outputs the laser light whose wavelength is 650 nm and thesecond semiconductor laser51bwhich outputs the laser light whose wavelength is 780 nm may be included.
• Each semiconductor laser arranged in proximity is mounted on the substrate, and only the predetermined distance leaves it and it is arranged in X axis direction. It is designed so that the outgoing direction of the maximum intensity of each light beam output from the[0319]light source unit51 be the −Z direction.
• The[0320]first semiconductor laser51ais chosen when theoptical disk15 is DVD, and thesecond semiconductor laser51bis chosen when theoptical disk15 is CD.
• The angle-of-[0321]divergence adjustment lens70 is arranged at the −Z plane of thelight source unit51, and is shown in FIG. 23.
• It is constituted including positive-meniscus-[0322]lens70bwhich adjusts the angle of divergence of the light beam (the second light beam) output from thesecond semiconductor laser51b(reduction), and the negative-meniscus-lens70awhich adjusts the angle of divergence of the light beam (the first light beam) output from thefirst semiconductor laser51a(expansion).
• If it is unified and the angle-of-[0323]divergence adjustment lens70 shifts, as for the negative-meniscus-lens70aand the positive-meniscus-lens70b, both meniscus lenses will also shift only the same distance in the same direction.
• In addition, the cylinder generating line in each meniscus lens lies at right angles mutually.[0324]
• The[0325]collimator lens52 is provided at the −Z plane of the angle-of-divergence adjustment lens70, and converts the light beam through the angle-of-divergence adjustment lens70 into the parallel light beam.
• The[0326]beam splitter54 is arranged at the −Z plane of thecollimator lens52.
• The[0327]object lens60 is arranged at the −Z plane of thebeam splitter54, focuses the light beam through thebeam splitter54 to form the light spot on the recording surface of theoptical disk15.
• The[0328]detection lens58 is arranged at the −X plane of thebeam splitter54, and the return light beam reflected by thebeam splitter54 is focused.
• The[0329]photodetector59 is arranged at the −X plane of thisdetection lens58. In thephotodetector59, four division light-receiving components are used as in the usual optical disk drive.
• The[0330]photodetector59 receives the return light beam from the recording surface of theoptical disk15, and outputs the signal including wobble signal information, reproduction data information, focal error information, track error information, etc. as in the usual optical pickup device.
• Referring back to FIG. 21, the operation of the optical-pickup-[0331]device23A which is constituted as mentioned above will be described. The angle of divergence is expanded by the negative-meniscus-lens70a, and after the light beam (the first light beam) output from thefirst semiconductor laser51ais made into the parallel light beam by thecollimator lens52, it is incident to thebeam splitter54.
• The first light beam through the[0332]beam splitter54 is focused on the recording surface of theoptical disk15 as a minute light spot through theobject lens60.
• On the other hand, the angle of divergence is reduced by the positive-meniscus-[0333]lens70b, and after the light beam (the second light beam) output from thesecond semiconductor laser51bis made into the parallel light beam by thecollimator lens52, it is incident to thebeam splitter54.
• The second light beam through the[0334]beam splitter54 is focused on the recording surface of theoptical disk15 as a minute light spot through theobject lens60.
• The received light beam reflected from the[0335]optical disk15 is converted into the parallel light beam by theobject lens60 as a return light beam, and it is incident to thebeam splitter54.
• The return light beam which is output in the direction of −X by the[0336]beam splitter54 is received by thephotodetector59 through thedetection lens58.
• From the[0337]photodetector59, the signal according to the amount of the received light is output to the reproductionsignal processing circuit28.
• Next, the procedure of manufacturing the optical-pickup-[0338]device23A will be described with reference to FIG. 24.
• At[0339]step401, as shown in FIG. 25A, thelight source unit51 and the angle-of-divergence adjustment lens70 are attached to thehousing50 of the optical pickup device.
• At this time, the[0340]light source unit51 is attached, after having been held by theelectrode holder61 to thehousing50.
• At[0341]step403, as shown in FIG. 25A, thecollimator lens81 as an optical element for making into the parallel light each light beam through each meniscus lens of the angle-of-divergence adjustment lens70 is arranged to the −Z plane of the angle-of-divergence adjustment lens70.
• The[0342]collimator lens81 is stationed so that thecollimator lens81 optical axis may be mostly in agreement with thecollimator lens52 optical axis.
• Then, the light-receiving[0343]component82 for detection as the first position transducer for receiving the light beam converted into the parallel light beam by thecollimator lens81 is arranged in the predetermined location by the −Z plane of thecollimator lens81.
• As shown in the wall by the side of one of Y-axis direction in FIG. 25B, the slide guide[0344]50aof the shape of the U character projected inside is formed in thehousing50.
• For this reason, the light-receiving[0345]component82 for detection is correctly positioned along with the slide guide50ain the above-mentioned predetermined location.
• In addition, the[0346]collimator lens81 and the light-receivingcomponent82 for detection may be unified.
• Moreover, as shown in FIG. 25A, the[0347]measurement control device83 are connected to theoptical element82 for detection.
• As a light-receiving[0348]component82 for detection, as shown in FIG. 26, the four-division light-receiving components separated by the parting line DX of X axis direction and the parting lines DY of Y axis direction are used.
• The light-receiving[0349]component82 for detection includes the first light-receivingcomponent82a, the second light-receivingcomponent82b, the third light-receivingcomponent82c, and the fourth light-receivingcomponent82d.
• It is the +X plane (the upper left side) of the parting line DY at the +Y plane of the parting line DX.[0350]
• The +X plane (the upper right side) of the parting line DY by the first light-receiving[0351]component82aand −Y plane of the parting line DX of the second light-receivingcomponent82b.
• Let the −X plane (the lower left side) of the parting line DY be the fourth light-receiving[0352]component82dfor the −X plane (the lower right side) of the parting line DY by the −Y plane of the parting line DX by the third light-receivingcomponent82cand +Y plane of the parting line DX.
• And the photo-electric-conversion signal in each partial light-receiving component is outputted to the[0353]measurement control device83.
• The intersection of each parting line is made into the origin/datum in this preferred embodiment, and the location based on the intensity of the light-receiving light beam shall be shown by making Y axis direction into the Y coordinate, making X axis direction as the X coordinate.[0354]
• The[0355]drive unit88 is attached in the angle-of-divergence adjustment lens70 atstep405.
• This[0356]drive unit88 drives the angle-of-divergence adjustment lens70 to X axis direction and Y-axis direction based on directions of themeasurement control device83.
• The[0357]measurement control device83 provide the output signals from the first light-receivingcomponent82a, as shown in FIG. 27.
• Converting into the electrical-potential-difference signal S[0358]82a, and the output signal from the second light-receivingcomponent82bis converted into the electrical-potential-difference signal S82b.
• The output signal from the third light-receiving[0359]component82cis converted into the electrical-potential-difference signal S82c.
• The[0360]I-V conversion circuit83afor changing the output signal from the fourth light-receivingcomponent82dinto the electrical-potential-difference signal S82d.
• The[0361]adder83bprovides addition of the signal S82aand signal S82b, and theadder83cprovides addition of the signal S82cand signal S82d. Theadder83eprovides addition of the signal S82band signal82c, and theadder83dprovides addition of the signal S82aand signal S82d.
• The[0362]subtractor83fprovides the difference signal of the output-signal S83cof theadder83cand the output-signal S83bof theadder83b.
• The subtractor[0363]83gprovides the difference signal of the output-signal S83dof theadder83dand the output-signal S83eof theadder83e.
• The[0364]compensation computation circuit83hcalculate the amount of location compensation of the angle-of-divergence adjustment lens70 based on the output signal SPx of thesubtractor83fand the output signal SPy of the subtractor83g.
• In the[0365]non-volatile memory83i, various information required for the operation of thecompensation computation circuit83hand the amount of location compensation are stored, and thedriver83jwhich outputs the drive signal to thedrive unit88 based on the operation results of thecompensation computation circuit83h.
• The[0366]compensation computation circuit83halso controls the on/off switching of each semiconductor laser.
• The signal SPx is computed by the operation processing of the following formula (1), and the signal SPy is computed by the operation processing of the following formula (2).[0367]
• SPx=(S82a+S82b)−(S82c+S82d)  (1)
• Spy=(S82a+S82d)−(S82b+S82c)  (2)
• The location compensation of the angle-of-[0368]divergence adjustment lens70 is directed to themeasurement control device83. Thereby, in themeasurement control device83, location compensation processing of the following steps407-step419 is performed.
• At[0369]step407, thefirst semiconductor laser51ais set in ON state by thecompensation computation circuit83h, so that the first light beam is output from thelight source unit51.
• This first light beam is received by the light-receiving[0370]component82 for detection through thecollimator lens81, after the angle of divergence is expanded by the negative-meniscus-lens70a.
• From each partial light-receiving component which constitutes the light-receiving[0371]component82 for detection, the signal according to the amount of the received light is outputted to themeasurement control device83.
• In the[0372]measurement control device83, the above-mentioned operation processing is performed and the signal SPx and signal SPy are computed.
• At[0373]step409, based on the signal SPx and signal SPy, the coordinates (Px1, Py1) of the intensity center location of the first light beam in the light-receiving side of the light-receivingcomponent82 for detection are computed, and the result is stored in thenon-volatile memory83iby thecompensation computation circuit83h.
• The[0374]first semiconductor laser51ais set in OFF state by thecompensation computation circuit83h, and the emission of the first light beam is stopped.
• At[0375]step411, thesecond semiconductor laser51bis set in ON state by thecompensation computation circuit83h, and the second light beam is output from thelight source unit51.
• This second light beam is received by the light-receiving[0376]component82 for detection through thecollimator lens81, after the angle of divergence is reduced by the positive-meniscus-lens70b.
• From each partial light-receiving component which constitutes the light-receiving[0377]component82 for detection, the signal according to the amount of the received light is outputted to themeasurement control device83.
• In the[0378]measurement control device83, the above-mentioned operation processing is performed and the signal SPx and signal SPy are computed.
• At[0379]step413, the coordinates (Px2, Py2) of the intensity center location of the second light beam in the light-receiving side of the light-receivingcomponent82 for detection is computed by thecompensation computation circuit83hbased on the signal SPx and signal SPy.
• The[0380]second semiconductor laser51bis set in OFF state by thecompensation computation circuit83h, and the emission of the second light beam is stopped.
• At[0381]step415, the coordinates (Px1, Py1) of the intensity center location of the first light beam and the coordinates (Px2, Py2) of the intensity center location of the second light beam are in agreement with thecompensation computation circuit83h.
• Based on the following formula (3), the amount Mx of location compensation of the angle-of-[0382]divergence adjustment lens70 about X axis direction is computed, and the amount My of location compensation of the angle-of-divergence adjustment lens70 about Y axis direction is computed based on the following formula (4).
• Mx=Rx×(Px2−Px1)  (3)
• My=Ry×(Py1−Py2)  (4)
• where Rx is a value acquired by the following formula (5) when the angle-of-[0383]divergence adjustment lens70 is moved by a distance Tx in X axis direction and the amount of movement in X axis direction of the intensity center location of the light beam received by the light-receivingcomponent82 is indicated by tx.
• Rx=Tx/tx  (5)
• Moreover, Ry is a value acquired by the following formula (6) when the angle-of-[0384]divergence adjustment lens70 is moved by a distance Ty in Y axis direction and the amount of movement in Y axis direction of the intensity center location of the light beam received by the light-receivingcomponent82 is indicated by ty.
• Ry=Ty/ty  (6)
• Rx and Ry are beforehand calculated by theoretical calculation or the experiment, and are stored in the[0385]non-volatile memory83i.
• The amounts Mx and My of location compensation of the angle-of-[0386]divergence adjustment lens70 are outputted to thedriver83jfrom thecompensation computation circuit83h.
• At[0387]step417, based on the amounts Mx and My of location compensation of the angle-of-divergence adjustment lens70, the drive signal is generated by thedriver83jand it is outputted to thedrive unit88.
• At[0388]step419, thedrive unit88 drives the angle-of-divergence adjustment lens70 based on the drive signal. Thereby, location compensation processing of the angle-of-divergence adjustment lens70 by themeasurement control device83 is completed.
• And the angle-of-[0389]divergence adjustment lens70 is fixed to thehousing50 with the screws.
• At[0390]step421, thecollimator lens81 and the light-receivingcomponent82 for detection are removed from the optical path.
• Moreover, the[0391]drive unit88 is also removed from the angle-of-divergence adjustment lens70.
• At[0392]step423, after attaching the remaining optical parts (thecollimator lens52 in FIG. 21, thebeam splitter54, theobject lens60, the detection lens58) and the remainingphotodetector59 which are not attached until now according to the design value in thehousing50, the manufacture of optical-pickup-device23A is completed by the processing attaching the lid (covering) of the housing.
• At this time, the optical system, the[0393]light source unit51, and thephotodetector59 are attached by the ideal location relation.
• Next, processing operation in the case of recording data on the[0394]optical disk15 is briefly explained using the above-mentioned optical-disk-drive20A.
• It can be distinguished from the intensity of the received light from the recording surface whether the[0395]optical disk15 is CD or DVD.
• Usually, this distinction is performed at the time of loading, when the[0396]optical disk15 is set to the predetermined location of optical-disk-drive20A.
• It is also possible to distinguish the kind of[0397]optical disk15 based on TOC (Table Of Contents) information, PMA (Program Memory Area) information, the wobble signal, etc. which are beforehand recorded on theoptical disk15.
• The distinction result is notified to the[0398]laser control circuit24, and the semiconductor laser of the control object is chosen by thelaser control circuit24.
• Therefore, it is assumed that one of the semiconductor laser is already chosen here.[0399]
• The[0400]CPU40 notifies the purport that the command of the record request is received from the host to the reproductionsignal processing circuit28 while outputting the control signal for controlling rotation of thespindle motor22 based on the specified record rate to themotor driver27, if the command of the record request is received from the host system.
• Moreover, the[0401]CPU40 accumulates the data received from the host to thebuffer RAM34 through thebuffer manager37.
• If rotation of the[0402]optical disk15 reaches the predetermined linear velocity, based on the output signal of thephotodetector59, the reproductionsignal processing circuit28 will detect the track error signal and the focal error signal, and will output them to theservo controller33.
• Based on the track error signal, the[0403]servo controller33 drives the tracking actuator of optical-pickup-device23A through themotor driver27, and corrects the tracking error.
• Based on the focal error signal, the[0404]servo controller33 drives the focusing actuator of the optical-pickup-device23A through themotor driver27, and corrects the focusing error.
• Thus, the tracking control and focusing control are performed.[0405]
• The reproduction[0406]signal processing circuit28 acquires address information based on the output signal of thephotodetector59, and notifies it to theCPU40.
• And the[0407]CPU40 outputs the specified signal which controls the seeking motor of the optical-pickup-device23A so that it writes in and optical-pickup-device23A is located in the start point to themotor driver27 based on address information.
• If the notice that the amount of data accumulated from the[0408]buffer manager37 at thebuffer RAM34 exceeded the predetermined value is received, theCPU40 is written in theencoder25 and directs creation of data.
• If the[0409]CPU40 determines that the location of optical-pickup-device23A writes in based on address information, and it is the start point, it will be notified to theencoder25.
• The[0410]encoder25 records write-in data on theoptical disk15 through thelaser control circuit24 and optical-pickup-device23A.
• Next, processing operation in the case of reproducing the data currently recorded on the[0411]optical disk15 using optical-disk-drive20A mentioned above is explained briefly.
• In addition, it is assumed that one of the semiconductor laser is already chosen like record processing.[0412]
• The[0413]CPU40 notifies the purport that the command of the reproduction request is received from the host to the reproductionsignal processing circuit28 while outputting the control signal for controlling rotation of thespindle motor22 based on the reproduction rate to themotor driver27, if the command of the reproduction request is received from the host.
• If rotation of the[0414]optical disk15 reaches the predetermined linear velocity, tracking control and focal control will be performed like the case of the above-mentioned record processing.
• Like the case of the above-mentioned record processing, the reproduction[0415]signal processing circuit28 detects address information, and notifies it to theCPU40.
• The[0416]CPU40 outputs the specified signal which controls the seeking motor so that it reads and optical-pickup-device23A is located in the start point to themotor driver27 based on address information.
• If the[0417]CPU40 determines that the location of optical-pickup-device23A reads, and it is the start point based on address information, it will be notified to the reproductionsignal processing circuit28.
• After the reproduction[0418]signal processing circuit28 detects RF signal based on the output signal of thephotodetector59 and performs error-correction processing etc., it is accumulated to thebuffer RAM34.
• The[0419]buffer manager37 transmits to the host through theinterface38, when the reproduction data accumulated at thebuffer RAM34 are assembled as sector data.
• In addition, tracking control and focal control are performed at any time until record processing and the regeneration are completed.[0420]
• In this preferred embodiment, the information acquisition process of the manufacture approach concerning the present invention is carried out by processing of[0421]step403 of FIG. 24—step415, and the compensation process is carried out by processing ofstep417 of FIG. 24, and step419 so that clearly from the above explanation.
• Moreover, the processor is realized in optical-disk-[0422]drive20A concerning this preferred embodiment by the reproductionsignal processing circuit28 and the program performed by theCPU40 and this theCPU40.
• As explained above, according to the manufacture approach of the optical pickup device concerning this preferred embodiment, it is the phase which attached the[0423]light source unit51 and the angle-of-divergence adjustment lens70.
• The[0424]first semiconductor laser51aandsecond semiconductor laser51bare made to emit light one by one, the first light beam to which the angle of divergence is expanded by negative-meniscus-lens70a, and the second light beam to which the angle of divergence is reduced by positive-meniscus-lens70bare received with the light-receivingcomponent82 for detection, respectively, and the intensity center location of each light beam is detected, respectively.
• When the intensity center location of each light beam is not in agreement, the mounting location of the angle-of-[0425]divergence adjustment lens70 is corrected so that the intensity center location of each light beam may be in agreement.
• Even if the outgoing direction of the first light beam when it is output from the[0426]light source unit51 and the outgoing direction of the second light beam are not mutually in agreement, when the angle-of-divergence adjustment lens70 is passed, the outgoing direction of each light beam is mutually in agreement.
• Therefore, it is possible to correct the deviation of the outgoing direction of each light beam output from the plurality of light sources.[0427]
• Moreover, since cheap 4 division light-receiving component is used as a light-receiving[0428]component82 for detection, location compensation processing of the angle-of-divergence adjustment lens70 can be performed at low cost.
• The preferred embodiment of FIG. 28 has the description at the point using the filter for choosing either the first light beam and the second light beam while making[0429]first semiconductor laser51aandsecond semiconductor laser51bemit light simultaneously in the case of location compensation processing of the angle-of-divergence adjustment lens mentioned above.
• In addition, in addition to this, the composition of the optical pickup device and the optical disk drive etc. is the same as that of the preferred embodiment of FIG. 24 mentioned above.[0430]
• Therefore, the explanation shall be omitted while using the sign same about the component equivalent to the first preferred embodiment mentioned above while explaining difference with the preferred embodiment of FIG. 24 below.[0431]
• The procedure of manufacturing optical-pickup-[0432]device23A in the preferred embodiment is shown to FIG. 28 by the flow chart.
• At[0433]step501, the same processing as the above-mentionedstep401 is performed.
• At[0434]step503, thecollimator lens81 is stationed in the predetermined location like the above-mentionedstep403.
• Next, as shown in FIG. 29A, the[0435]filter84 is arranged to the −Z plane of thecollimator lens81.
• In this step, it is arranged so that the light beam is converted into the parallel light beam by the[0436]collimator lens81 and it is incident to a part of the filter84 (the lower half of FIG. 29A).
• As shown in FIG. 29B, the[0437]filter84 has a disk configuration and is divided into two penetration ranges (first penetration range84a,second penetration range84b) by the straight line passing through the center.
• The[0438]first penetration range84ahas the property of making the first light beam penetrating alternatively, and thesecond penetration range84bhas the property of making the second light beam penetrating alternatively.
• The[0439]filter84 comprises the rotation drive mechanism, and can be rotated within XY plane with directions of measurement control-device83′ by setting the axis of rotation as the shaft of Z-axis direction passing through the center.
• Then, the light-receiving[0440]component82 for detection is arranged to the −Z plane of thefilter84.
• As shown in FIG. 29A, the measurement control-[0441]device83′ is connected to theoptical element82 for detection.
• As shown in FIG. 30, the[0442]measurement control device83′ uses, instead of the above-mentionedcircuit83hof themeasurement control device83, thecompensation computation circuit83h′ having the additional function to control thefilter84.
• Other composition is the same as that of the[0443]measurement control device83, and a description thereof will be omitted.
• At[0444]step505, the same processing as the above-mentionedstep405 is performed.
• And location compensation of the angle-of-[0445]divergence adjustment lens70 is directed to the measurement control-device83′.
• Thereby, in the measurement control-[0446]device83′, location compensation processing of the following steps507-521 is performed.
• At[0447]step507, rotation of thefilter84 is controlled by thecompensation computation circuit83h′ so that the light beam is converted into the parallel light beam by thecollimator lens81 and it is incident to thefirst penetration range84a.
• At[0448]step509, thefirst semiconductor laser51aandsecond semiconductor laser51bare set in ON state by thecompensation computation circuit83h′, and the first light beam and second light beam are output from thelight source unit51.
• After the angle of divergence is expanded by the negative-meniscus-[0449]lens70a, the first light beam is incident to thefilter84 through thecollimator lens81.
• After the angle of divergence is reduced by the positive-meniscus-[0450]lens70b, the second light beam is incident to thefilter84 through thecollimator lens81.
• In the[0451]filter84, only the first light beam passes through it, and the first light beam is received by the light-receivingcomponent82 for detection.
• From each partial light-receiving component which constitutes the light-receiving[0452]component82 for detection, the signal according to the amount of the received light is outputted to the measurement control-device83′.
• In the measurement control-[0453]device83′, the signal SPx and signal SPy are computed as in the previous preferred embodiment.
• At[0454]step511, the same processing as the above-mentionedstep409 is performed.
• At[0455]step513, rotation of thefilter84 is controlled by thecompensation computation circuit83h′ so that thefilter84 is rotated by 180 degrees, the light beam is converted into the parallel light beam by thecollimator lens81 and it is incident to thesecond penetration range84b.
• Thereby, in the[0456]filter84, only the second light beam passes through it, and the second light beam is received by the light-receivingcomponent82 for detection.
• From each partial light-receiving component which constitutes the light-receiving[0457]component82 for detection, the signal according to the amount of the received light is outputted to the measurement control-device83′.
• In the measurement control-[0458]device83′, the signal SPx and signal SPy are computed as in the previous preferred embodiment.
• At steps[0459]515-521, the same processing as the above-mentioned steps413-419 is performed.
• The location compensation processing of the angle-of-[0460]divergence adjustment lens70 by the measurement control-device83′ is thus completed.
• At[0461]step523, thecollimator lens81, thefilter84, and the light-receivingcomponent82 for detection are removed from the optical path. Thedrive unit88 is also removed from the angle-of-divergence adjustment lens70.
• At[0462]step525, the same processing as the above-mentionedstep423 is performed, and the manufacture of the optical-pickup-device23A is completed.
• At this time, the optical system, the[0463]light source unit51, and thephotodetector59 are attached by the ideal location relation.
• In this preferred embodiment, the information acquisition process of the manufacture approach concerning the present invention is carried out by the processing of steps[0464]503-517, and the compensation process is carried out by the processing ofsteps519 and521.
• Moreover, in the optical-disk-[0465]drive20A of this preferred embodiment, the processing is realized like the preferred embodiment of FIG. 24 by the reproductionsignal processing circuit28 and the program performed by theCPU40, and the recording processing and the reproduction processing are performed as in the preferred embodiment of FIG. 24.
• The preferred embodiment of FIG. 31 is characterized by using the dichroic prism as a branch optical element for separating the first light beam and the second light beam while controlling the[0466]first semiconductor laser51aandsecond semiconductor laser51bto emit light simultaneously in the case of location compensation processing of the angle-of-divergence adjustment lens70.
• In addition, the composition of the optical pickup device and the optical disk drive etc. is the same as that of the preferred embodiment of FIG. 24.[0467]
• Therefore, the explanation shall be omitted while using the sign same about the component equivalent to the first preferred embodiment mentioned above while explaining focusing on difference with the preferred embodiment of FIG. 24 below.[0468]
• The procedure of manufacturing optical-pickup-[0469]device23A in this preferred embodiment is shown to FIG. 31 by the flow chart.
• At[0470]step601, the same processing as the above-mentionedstep401 is performed.
• At[0471]step603, thecollimator lens81 is first stationed like the above-mentionedstep403.
• Next, as shown in FIG. 32A, the[0472]dichroic prism85 is arranged to the −Z plane of thecollimator lens81.
• The first light beam is made into the parallel light beam by the[0473]collimator lens81 and it passes through thedichroic prism85, and the second light beam is set up so that it may be reflected in the direction of +X by thedichroic prism85.
• The light-receiving[0474]component82 for detection for receiving the first light beam through thedichroic prism85 is arranged to the −Z plane of thedichroic prism85, and the light-receivingcomponent86 for detection as the second position transducer for receiving the second light beam reflected in the direction of +X by thedichroic prism85 is arranged to the +X plane of thedichroic prism85.
• Each light-receiving component for detection is arranged through the slide guide of the shape of the U character formed in the housing in the predetermined location, respectively.[0475]
• As a light-receiving[0476]component86 for detection, as shown in FIG. 32B, the four-division light-receiving components (the first light-receivingcomponent86a, the second light-receivingcomponent86b, the third light-receivingcomponent86c, and the fourth light-receivingcomponent86d) as well as the light-receivingcomponent82 for detection is used.
• As shown in FIG. 32A, measurement control-[0477]device83″ is connected to theoptical element82 for detection, and theoptical element86 for detection.
• As the above-mentioned measurement control-[0478]device83″ is shown in FIG. 33, the adder and the subtractor from which signal SPy′ is obtained for signal SPx′ based on the following formula (8) based on the following formula (7) are added.
• The signal S[0479]86ais the electrical-potential-difference signal which changed the output signal of the first light-receivingcomponent86a.
• The signal S[0480]86bis the electrical-potential-difference signal which changed the output signal of the second light-receivingcomponent86b, signal S86cis the electrical-potential-difference signal which changed the output signal of the third light-receivingcomponent86c, and signal S86dis the electrical-potential-difference signal which changed the output signal of the fourth light-receivingcomponent86d.
• The signal SPx′ and signal SPy′ are outputted to the[0481]compensation computation circuit83h″ with the signal SPx and signal SPy.
• SPx′=(S86a+S86b)−(S86c+S86d)  (7)
• SPy′=(S86a+S86d)−(S86b+S86c)  (8)
• Other composition is the same as that of the[0482]measurement control device83.
• The explanation is omitted while using the same reference numeral for the below about the component equivalent to the[0483]measurement control device83.
• At[0484]step605, the same processing as the above-mentionedstep405 is performed.
• And location compensation of the angle-of-[0485]divergence adjustment lens70 is directed to the measurement control-device83″.
• Thereby, in the measurement control-[0486]device83″, location compensation processing of the following steps607-617 is performed.
• At[0487]step607, thefirst semiconductor laser51aandsecond semiconductor laser51bare made the ON state by thecompensation computation circuit83h″, and the first light beam and second light beam are output from thelight source unit51.
• After the angle of divergence is expanded in negative-meniscus-[0488]lens70a, the first light beam is incident to thefilter84 through thecollimator lens81.
• After the angle of divergence is reduced in positive-meniscus-[0489]lens70b, incidence of the second light beam is carried out to thedichroic prism85 through thecollimator lens81.
• The first light beam through the[0490]dichroic prism85 is received with the light-receivingcomponent82 for detection.
• From each partial light-receiving component which constitutes the light-receiving[0491]component82 for detection, the signal according to the amount of the received light is outputted to the measurement control-device83″.
• In the measurement control-[0492]device83″, the signal SPx and signal SPy are computed like the first preferred embodiment of the above.
• The second light beam reflected by the[0493]dichroic prism85 is received with the light-receivingcomponent86 for detection.
• From each partial light-receiving component which constitutes the light-receiving[0494]component86 for detection, the signal according to the amount of the received light is outputted to measurement control-device83″.
• In the measurement control-[0495]device83″, the signal SPx′ and signal SPy′ are computed as mentioned above.
• At[0496]step609, the coordinates (Px1, Py1) of the intensity center position of the first light beam are computed by thecompensation computation circuit83h″ based on the signal SPx and signal SPy.
• At[0497]step611, the coordinates (Px2, Py2) of the intensity center location of the second light beam are computed by thecompensation computation circuit83h″ based on the signal SPx′ and signal SPy′.
• At steps[0498]613-617, the same processing as the above-mentioned steps415-419 is performed.
• And location compensation processing of the angle-of-[0499]divergence adjustment lens70 by the measurement control-device83″ is completed.
• At[0500]step619, thecollimator lens81, thedichroic prism85, and the light-receivingcomponents82 and86 for detection are removed from the optical path.
• Moreover, the[0501]drive unit88 is also removed from the angle-of-divergence adjustment lens70.
• At[0502]step621, the same processing as the above-mentionedstep423 is performed, and the manufacture of the optical-pickup-device23A is completed.
• At this time, the optical system, the[0503]light source unit51, and thephotodetector59 are attached by the ideal location relation.
• In this preferred embodiment, the information acquisition process of the manufacture approach concerning the present invention is carried out by the processing of steps[0504]603-613, and the compensation process is carried out by processing ofsteps615 andstep617.
• Moreover, in the optical-disk-[0505]drive20A of this preferred embodiment, the processing is realized like the preferred embodiment of FIG. 24 by the reproductionsignal processing circuit28 and the program performed by theCPU40, and recording processing and reproduction are performed like the preferred embodiment of FIG. 24.
• As explained above, according to the manufacture approach of the optical pickup device concerning the present invention, the deviation of the outgoing direction of each of the light beams output from the plurality of light sources can be corrected with sufficient accuracy.[0506]
• Moreover, according to the optical pickup device of the present invention, generating of the wavefront aberration resulting from the deviation of the outgoing direction of each of the light beams output from the plurality of light sources, and the reduction of optical efficiency can be controlled.[0507]
• According to the optical disk drive concerning the present invention, it can respond to two or more kinds of information storage mediums, and it is stabilized with sufficient accuracy and access at the high speed to each information storage medium can be performed.[0508]
• Next, FIG. 34 shows the composition of the optical disk drive in another preferred embodiment of the present invention in which the optical pickup device of another preferred embodiment is provided.[0509]
• The[0510]optical disk drive20B in FIG. 34 comprises thespindle motor22 for carrying out the rotation drive of theoptical disk15 as an information storage medium, theoptical pickup device23B, thelaser control circuit24, theencoder25, thedriver27, the reproductionsignal processing circuit28, theservo controller33, thebuffer RAM34, thebuffer manager37, theinterface38, theROM39, theCPU40, theRAM41 etc.
• Moreover, in this preferred embodiment, the[0511]optical disk drive20B can respond to the-two kinds of optical disks, CD and DVD.
• The[0512]optical pickup device23B is provided for receiving the received light from the recording surface and for irradiating laser light to the recording surface of theoptical disk15 in which the tracks in the spiral or concentric formation are formed.
• The reproduction[0513]signal processing circuit28 of FIG. 34 converts into the electrical-potential-difference signal the current signal which is the output signal of theoptical pickup device23B, and detects the wobble signal, the RF signal, the servo signal (the focusing error signal, tracking error signal), etc. based on this electrical-potential-difference signal.
• The reproduction[0514]signal processing circuit28 extracts address information, the synchronizing signal, etc. from the wobble signal.
• The address information extracted here is outputted to the[0515]CPU40, and the synchronizing signal is outputted to theencoder25.
• Furthermore, after the reproduction[0516]signal processing circuit28 performs error-correction processing etc. to RF signal, it is stored in thebuffer RAM34 through thebuffer manager37.
• Moreover, the servo signal is outputted to the[0517]servo controller33 from the reproductionsignal processing circuit28.
• The[0518]servo controller33 generates the control signal which controls theoptical pickup device23B based on the servo signal, and outputs it to thedriver27.
• The[0519]buffer manager37 will notify to theCPU40, if I/O of the data to thebuffer RAM34 is managed and the accumulated amount of data becomes the predetermined value.
• The[0520]driver27 controls theoptical pickup device23B and thespindle motor22 based on directions of the control signal from theservo controller33, and theCPU40.
• The[0521]encoder25 takes out the data accumulated at thebuffer RAM34 through thebuffer manager37 based on directions of theCPU40, performs addition of the error correction code etc., and creates the write-in signal to theoptical disk15.
• The[0522]encoder25 outputs the write-in signal to thelaser control circuit24 synchronizing with the synchronizing signal from the reproductionsignal processing circuit28 based on the directions from theCPU40.
• The[0523]laser control circuit24 controls the laser light output from theoptical pickup device23B based on the write-in signal from theencoder25.
• In addition, the[0524]laser control circuit24 makes the control object one side of the two light sources of theoptical pickup device23B later mentioned based on directions of theCPU40.
• The[0525]interface38 is the bi-directional communication interface with the host (for example, personal computer), and is based on the standard interfaces, such as ATAPI (AT Attachment Packet Interface) and SCSI (Small Computer System Interface).
• The program described in code decipherable by the[0526]CPU40 is stored in theROM39.
• And the[0527]CPU40 temporarily stores the data required for control in theRAM41 while controlling operation of each part of the above according to the program stored in theROM39.
• Next, the composition of the above-mentioned[0528]optical pickup device23B will be explained with based on FIG. 35A and FIG. 35B.
• The[0529]optical pickup device23B outputs the laser light whose wavelength is 660 nm or the laser light whose wavelength is 785 nm alternatively, as shown in FIG. 35A.
• The[0530]optical pickup device23B comprises the optical module LM which receives the return light beam from the recording surface of theoptical disk15, the first angle-of-divergence adjustment component M1, the second angle-of-divergence adjustment component M2, thecoupling lens52, theobject lens60, and the drive system (the focusing actuator, the tracking actuator, and seeking motor).
• The optical module LM comprises the light-emission portion EL and the light-receiving portion RL as shown in FIG. 35B.[0531]
• The light-emission portion EL comprises the[0532]first semiconductor laser53 which outputs the laser light whose wavelength is 660 nm, and thesecond semiconductor laser54 which outputs the laser light whose wavelength is 785 nm.
• The light-receiving portion RL comprises the light-receiving[0533]component59 as a photodetector which branched by thehologram61 as a branch optical element which branches the return light beam from the recording surface of theoptical disk15, and thehologram61 and which returns and receives the light beam.
• The[0534]first semiconductor laser53 is chosen when theoptical disk15 is DVD, and thesecond semiconductor laser54 is chosen when theoptical disk15 is CD.
• Let the outgoing direction of maximum intensity of the light beam output from each semiconductor laser be the −Z direction in this preferred embodiment.[0535]
• In this preferred embodiment, as shown in FIG. 36, the[0536]first semiconductor laser53 and thesecond semiconductor laser54 are arranged so that the activation layers AL1 and AL2 may become parallel to XZ plane.
• Therefore, the light beam output from each semiconductor laser is divergence light with the optical intensity distribution of the ellipse form which makes Y-axis direction the direction of the transverse.[0537]
• The light beam (the first outgoing beam) with the angle of divergence θ1Y in YZ plane and the angle of divergence θ1Z in XZ plane, output from the[0538]first semiconductor laser53, has the relation of θ1Y>θ1Z, rather than is the same, as shown in FIG. 37A and FIG. 37B.
• Similarly, the light beam (the second outgoing beam) with the angle of divergence θ2Y in YZ plane and the angle of divergence θ2Z in XZ plane, output from the[0539]second semiconductor laser54, has the relation of θ2Y>θ2Z, rather than is the same, as shown in FIG. 38A and FIG. 38B.
• Referring to FIG. 35B, the above-mentioned[0540]hologram61 fixed to the output aperture is arranged at the −Z plane of each semiconductor laser.
• The[0541]photodetector59 contains two or more light-receiving components which output the optimal signal for detecting the wobble signal, the reproduction signal, and the servo signal.
• Referring to FIG. 35A, the angle-of-divergence adjustment component M[0542]1 of the first is arranged at the −Z plane of the optical module LM.
• The first angle-of-divergence adjustment component M[0543]1 has wavelength-selection nature, and adjusts the angle of divergence of the first outgoing beam alternatively.
• The angle-of-divergence adjustment component M[0544]2 of the second is arranged at the −Z plane of the first angle-of-divergence adjustment component M1.
• This second angle-of-divergence adjustment component M[0545]2 has wavelength-selection nature, and adjusts the angle of divergence of the second outgoing beam alternatively.
• As the first angle-of-divergence adjustment component M[0546]1 and the second angle-of-divergence adjustment component M2, the optical element using the ingredient from which the index of refraction differs with wavelength, for example like the polymer liquid crystal is used.
• When the focal distance of the[0547]coupling lens52 is set to fcl, the diameter of beam φ dvd of the first outgoing beam through thecoupling lens52 can be calculated by the following formula (31), as shown in FIG. 39. Here, θ1 is the angle of divergence of the first outgoing beam incident to thecoupling lens52.
• φdvd=2×fcl×sin(θ1/2)  (31)
• The diameter of beam φ cd of the second outgoing beam through the[0548]coupling lens52 can be calculated by the following formula (32).
• Here, θ2 is the angle of divergence of the second outgoing beam incident to the[0549]coupling lens52.
• 100cd=2×fcl×sin(θ2/2)  (32)
• The rim intensity will become high, if the correlation is between the angles of divergence of the light beam and the rim intensity, which is incident to the[0550]coupling lens52, and the angle of divergence becomes large, as shown in FIG. 40.
• When designing more highly than the rim intensity in the case of CD the rim intensity in the case of DVD, it is necessary to satisfy the following formula (33).[0551]
• φdvd>φcd  (33)
• That is, it is necessary to satisfy the following formula (34).[0552]
• θ1>θ2  (34)
• For example, θ1 will become 7.7 degrees if the focal distance fcl of the[0553]coupling lens52 is 11 mm in order to make the rim intensity in the case of CD into 15% (optical efficiency=about 50%) for the rim intensity in the case ofDVD 30% (optical efficiency=about 45%), θ2 will become 11 degrees.
• Although the light beam Bdvd incorporated by the[0554]object lens60 among the first outgoing beam is the rim intensity=30% mostly about Y axis direction in this preferred embodiment when there is no first angle-of-divergence adjustment component M1 as shown in FIG. 41A, about X axis direction, it shall be the rim intensity<30%.
• As shown in FIG. 41B, when there is no second angle-of-divergence divergence adjustment component M[0555]2, although the light beam Bcd incorporated by theobject lens60 among the second outgoing beam is rim intensity=15% about X axis direction, it shall be rim intensity>15% about Y axis direction.
• The first angle-of-divergence adjustment component M[0556]1 doubles the angle of divergence θ1Z within XZ plane of the first outgoing beam (θ1Y/θ1Z>1).
• Thereby, as shown in FIG. 42A, the angle of divergence within XZ plane of the first outgoing beam through the first angle-of-divergence adjustment component M[0557]1 becomes larger than the angle of divergence θ1Z, and becomes almost equal to the angle of divergence θ1Y within YZ plane.
• The light beam incorporated by the[0558]object lens60 becomes rim intensity=30% about X-axis direction.
• The second angle-of-divergence adjustment component M[0559]2 doubles the angle of divergence θ2Y within YZ plane of the second outgoing beam (θ2Z/θ2Y <1).
• Thereby, as shown in FIG. 42B, the angle of divergence within YZ plane of the second outgoing beam through the second angle-of-divergence adjustment component M[0560]2 becomes smaller than the angle of divergence θ2Y, and becomes almost equal to the angle of divergence θ2Z within XZ plane.
• The light beam incorporated by the[0561]object lens60 becomes the rim intensity=15% about Y-axis direction.
• The[0562]coupling lens52 is arranged at the −Z plane of the second angle-of-divergence adjustment component M2, and makes the first outgoing beam and the second outgoing beam parallel light, respectively.
• The above-mentioned[0563]object lens60 is arranged at the −Z plane of thecoupling lens52.
• The[0564]object lens60 condenses the light beam through thecoupling lens52, and forms the optical spot on the recording surface of theoptical disk15.
• The action of the[0565]optical pickup device23B constituted as mentioned above is explained.
• First, the case where the[0566]optical disk15 is DVD is explained.
• The light beam output from the[0567]first semiconductor laser53 is incident to thehologram61.
• The angle of divergence in XZ plane of the first angle-of-divergence adjustment component M[0568]1 in the light beam through thehologram61 is expanded.
• After this light beam penetrates the second angle-of-divergence adjustment component M[0569]2 as it is and serves as parallel light with thecoupling lens52, it is focused on the recording surface of theoptical disk15 as a minute spot through theobject lens60.
• Let again the received light reflected in respect of record of the[0570]optical disk15 be parallel light with theobject lens60 as a return light beam.
• After this return light beam penetrates the[0571]collimator lens52, incidence of it is carried out to thehologram61 through the second angle-of-divergence adjustment component M2 and the first angle-of-divergence adjustment component M1.
• The return light beam diffracted by the[0572]hologram61 is received by thephotodetector59.
• Each light-receiving component which constitutes the[0573]photodetector59 outputs the current signal according to the amount of the received light to the reproductionsignal processing circuit28, respectively.
• Next, the case where the[0574]optical disk15 is CD is explained.
• The light beam output from the[0575]second semiconductor laser54 is incident to thehologram61.
• The light beam through the[0576]hologram61 penetrates the first angle-of-divergence adjustment component M1 as it is, and it carries out incidence to the second angle-of-divergence adjustment component M2.
• After the angle of divergence in YZ plane is reduced with the second angle-of-divergence adjustment component M[0577]2 and this light beam serves as parallel light with thecoupling lens52, it is focused on the recording surface of theoptical disk15 as a minute spot through theobject lens60.
• Let again the received light reflected in respect of record of the[0578]optical disk15 be parallel light with theobject lens60 as a return light beam.
• After this return light beam penetrates the[0579]collimator lens52, incidence of it is carried out to thehologram61 through the second angle-of-divergence adjustment component M2 and the first angle-of-divergence adjustment component M1.
• The return light beam diffracted by the[0580]hologram61 is received by thephotodetector59.
• Each light-receiving component which constitutes the[0581]photodetector59 outputs the current signal according to the amount of the received light to the reproductionsignal processing circuit28, respectively.
• It can be distinguished from the intensity of the received light from the optical disk whether the[0582]optical disk15 is CD or DVD.
• Usually, this distinction is performed when the[0583]optical disk15 is intercalated in the predetermined location of theoptical disk drive20B (at the time of loading).
• It is also possible to distinguish the kind of[0584]optical disk15 based on TOC (Table Of Contents) information, PMA (Program Memory Area) information, the wobble signal, etc. which are beforehand recorded on theoptical disk15.
• The distinction result is notified to the[0585]laser control circuit24, and either thefirst semiconductor laser53 and thesecond semiconductor laser54 are chosen by thelaser control circuit24.
• Next, processing operation in the case of recording data on the[0586]optical disk15 is briefly explained using the above-mentionedoptical disk drive20B.
• In addition, selection of the semiconductor laser shall already have been performed.[0587]
• The[0588]CPU40 notifies the purport that the command of the record request is received from the host to the reproductionsignal processing circuit28 while outputting the control signal for controlling rotation of thespindle motor22 based on the record rate to thedriver27, if the command of the record request is received from the host system.
• The[0589]CPU40 accumulates the data received from the host to thebuffer RAM34 through thebuffer manager37.
• If rotation of the[0590]optical disk15 reaches the predetermined linear velocity, based on the output signal of thephotodetector59, the reproductionsignal processing circuit28 will detect the tracking error signal and the focusing error signal, and will output them to theservo controller33.
• In the[0591]servo controller33, the tracking actuator and focusing actuator of theoptical pickup device23B are driven through thedriver27 based on the tracking error signal and focusing error signal from the reproductionsignal processing circuit28.
• The track gap and the focal gap are corrected.[0592]
• The reproduction[0593]signal processing circuit28 acquires address information based on the output signal of thephotodetector59, and notifies it to theCPU40.
• The[0594]CPU40 outputs the specified control signal which controls the seeking motor of theoptical pickup device23B so that it writes in and theoptical pickup device23B is located in the start point to thedriver27 based on the address information.
• If the notice that the amount of data accumulated from the[0595]buffer manager37 at thebuffer RAM34 exceeded the predetermined value is received, theCPU40 is written in theencoder25 and directs creation of the signal.
• If the[0596]CPU40 determines that the location of theoptical pickup device23B writes in based on address information, and it is the start point, it will be notified to theencoder25.
• The[0597]encoder25 records the write-in signal on the optical disk through thelaser control circuit24 and theoptical pickup device23B.
• Next, processing operation in the case of reproducing the data currently recorded on the[0598]optical disk15 using theoptical disk drive20B mentioned above is explained briefly.
• In addition, selection of the semiconductor laser shall be carried out as described above, and shall already have been performed.[0599]
• The[0600]CPU40 notifies the purport that the command of the reproduction request is received from the host to the reproductionsignal processing circuit28 while outputting the control signal for controlling rotation of thespindle motor22 based on the reproduction rate to thedriver27, if the command of the reproduction request is received from the host system.
• If rotation of the[0601]optical disk15 reaches the predetermined linear velocity, tracking control and focal control of theobject lens60 will be performed like the case of the above-mentioned record processing.
• Like the case of the above-mentioned record processing, the reproduction[0602]signal processing circuit28 detects address information, and notifies it to theCPU40.
• The[0603]CPU40 outputs the specified control signal which controls the seeking motor so that it reads and theoptical pickup device23B is located in the start point to thedriver27 based on address information.
• If the[0604]CPU40 determines that the location of theoptical pickup device23B reads and it is the start point based on address information, it will be notified to the reproductionsignal processing circuit28.
• After the reproduction[0605]signal processing circuit28 detects RF signal based on the output signal of theoptical pickup device23B and performs error-correction processing etc., it is accumulated to thebuffer RAM34.
• The[0606]buffer manager37 transmits to the host through theinterface38, when the reproduction data accumulated at thebuffer RAM34 are assembled as sector data.
• In addition, as mentioned above, the reproduction[0607]signal processing circuit28 detects the focusing error signal and the tracking error signal based on the output signal from theoptical pickup device23B, and corrects the focal gap and the track gap at any time through theservo controller33 and thedriver27, until record processing and the regeneration are completed.
• In the optical disk drive concerning this preferred embodiment, the processor is realized by the program performed by the reproduction[0608]signal processing circuit28, theCPU40, and this theCPU40 so that clearly from the above explanation.
• However, the present invention is not limited to this example.[0609]
• It is appropriate also to constitute a part of the composition realized by the processing according to the program by the[0610]CPU40 by hardware. Or it is appropriate also to constitute all the composition by hardware.
• As explained above, according to the optical pickup device concerning this preferred embodiment, the angle of divergence θ1Z within XZ plane of the light beam output from the[0611]first semiconductor laser53 is expanded twice (θ1Y/θ1Z>1) using the first angle-of-divergence adjustment component M1.
• The light beam incorporated by the[0612]object lens60 among the light beams which are output from thefirst semiconductor laser53 becomes rim intensity=30% mostly also about X axis direction.
• Therefore, it is possible to form the optimal optical spot for DVD on the recording surface thereof.[0613]
• According to this preferred embodiment, the angle of divergence θ2Y within YZ plane of the light beam output from the[0614]second semiconductor laser54 is reduced twice (θ2Z/θ2Y <1) using the second angle-of-divergence adjustment component M2.
• The light beam incorporated by the[0615]object lens60 among the light beams which are output from thesecond semiconductor laser54 becomes rim intensity=15% mostly also about Y axis direction.
• Therefore, most light beams which are output from the[0616]second semiconductor laser54 will be incorporated by theobject lens60, and it becomes possible to raise optical efficiency of it.
• Therefore, it is possible to form the optimal optical spot for CD in the recording surface thereof, and this can respond to improvement in the speed of the access rate.[0617]
• Since the light beam by which incidence is carried out to the[0618]coupling lens52 has the optimal optical intensity distribution for the wavelength according to this preferred embodiment, the light beam incorporated by theobject lens60 can secure the optimal rim intensity for the wavelength.
• Therefore, without causing enlargement and high cost, it can respond to two or more kinds of optical disks, and the optimal optical spot for each optical disk can be formed on the recording surface thereof.[0619]
• According to this preferred embodiment, since the optical intensity distribution serves as the circle configuration mostly, the light beam through the[0620]coupling lens52 can become possible [extracting the light beam to the diameter of the beam mostly made into the ideal], and can raise optical efficiency further.
• According to this preferred embodiment, since the first angle-of-divergence adjustment component and the second angle-of-divergence adjustment component are arranged between the hologram and the coupling lens, the thing which diffracted by the hologram and which it returns and interferes in the light beam with the first angle-of-divergence adjustment component and the second angle-of-divergence adjustment component can be prevented.[0621]
• Therefore, it becomes possible to stabilize the signal outputted from the photodetector.[0622]
• According to the optical disk drive of this preferred embodiment, the optimal optical spot can be formed on the recording surface of each optical disk (DVD and CD), and it is possible to stably perform recording and reproduction of exact information. Furthermore, the miniaturization of the optical disk drive itself can also be promoted by the miniaturization of the[0623]optical pickup device23.
• For example, when used as a portable device, carrying the optical pickup device of the present invention becomes easy and becomes usable for a long time.[0624]
• Although the above-mentioned preferred embodiment explained the case where the first angle-of-divergence adjustment component M[0625]1 and the second angle-of-divergence adjustment component M2 are arranged individually, it is not limited to this example.
• The first angle-of-divergence adjustment component M[0626]1 and the second angle-of-divergence adjustment component M2 may be unified.
• The components mark at the time of attachment can decrease, attachment work and tuning can be simplified, and it becomes possible to reduce work cost.[0627]
• Although the above-mentioned preferred embodiment explained the case where the first angle-of-divergence adjustment component M[0628]1 is arranged at the light source side, it is not limited to this example.
• The second angle-of-divergence adjustment component M[0629]2 may be arranged at the light source side.
• Although the above-mentioned preferred embodiment explained the case where the optical element (the first angle-of-divergence adjustment component M[0630]1, second angle-of-divergence adjustment component M2) which has wavelength-selection nature as an optical element for changing the angle of divergence is used, it is not limited to this example.
• As shown in FIG. 43A, it is possible to arrange the first lens LI which changes the angle of divergence θ1Z within XZ plane twice (θ1Y/θ1Z>1) to the −Z plane of the[0631]first semiconductor laser53.
• As shown in FIG. 43B, it is possible to arrange the second lens L[0632]2 which changes the angle of divergence θ2Y within YZ plane twice (θ2Z/θ2Y <1) to the −Z plane of thesecond semiconductor laser54.
• In this case, as shown in FIG. 44, the first lens L[0633]1 and the second lens L2 may be mounted in the optical module LM1, respectively.
• Instead of the first angle-of-divergence adjustment component M[0634]1 and the second angle-of-divergence adjustment component M2, as shown in FIG. 45, it is possible to use the third angle-of-divergence adjustment component M3 which can control the amount of adjustments of the angle of divergence by the supply voltage.
• When the optical disk is DVD, as shown in FIG. 46A, the electrical potential difference V[0635]1 is impressed to the third angle-of-divergence adjustment component M3 through thedriver27 by directions of theCPU40, and the angle of divergence θ1Z within XZ plane is expanded twice (θ1Y/θ1Z>1).
• When the optical disk is CD, as shown in FIG. 46B, the electrical potential difference V[0636]2 is impressed to the third angle-of-divergence adjustment component M3 through thedriver27 by directions of theCPU40, and the angle of divergence θ2Y within YZ plane is reduced twice (θ2Z/θ2Y <1).
• As the third angle-of-divergence adjustment component M[0637]3, the crystalline-liquid lens as disclosed in Japanese Laid-Open Patent Application No. 5-54414 can be used.
• Although the case where the rim intensity of Y axis direction in the light beam incorporated by the[0638]object lens60 among the light beams which are output from thefirst semiconductor laser53 is about 30% is explained by the above-mentioned preferred embodiment when there is no first angle-of-divergence adjustment component M1, it is not limited to this example.
• For example, the rim intensity of Y-axis direction may be smaller than 30%.[0639]
• In this case, the optical element which has the action which enlarges both the angle of divergence θ1Y in YZ plane of the light beam output from the[0640]first semiconductor laser53, and the angle of divergence θ1Z in XZ plane instead of the first angle-of-divergence adjustment component M1 needs to use so that it may become the rim intensity=30% mostly about Y axis direction and X axis direction.
• Although the case where the rim intensity of X axis direction in the light beam incorporated by the[0641]object lens60 among the light beams which are output from thesecond semiconductor laser54 is about 15% is explained by the above-mentioned preferred embodiment when there is no second angle-of-divergence adjustment component M2, it is not limited to this example.
• For example, the rim intensity of X-axis direction may be larger than 15%.[0642]
• In this case, the optical element which has the action which makes small both the angle of divergence θ2Y in YZ plane of the light beam output from the[0643]second semiconductor laser54, and the angle of divergence θ2Z in XZ plane instead of the second angle-of-divergence adjustment component M2 needs to use so that it may become the rim intensity=15% mostly about Y axis direction and X axis direction.
• Although the above-mentioned preferred embodiment explained the case where the second angle-of-divergence adjustment component M[0644]2 which makes small the first angle-of-divergence adjustment component M1 which enlarges the angle of divergence of the first outgoing beam, and the angle of divergence of the second outgoing beam is used, it is not limited to this example.
• For example, when the optimal coupling lens for the first outgoing beam is used, the first angle-of-divergence adjustment component M[0645]1 is unnecessary.
• In this case, since the amount of adjustments of the angle of divergence becomes large to the second outgoing beam, it is necessary to use the different optical element from the second angle-of-divergence adjustment component.[0646]
• Moreover, when the optimal coupling lens for the second outgoing beam is used for example, the second angle-of-divergence adjustment component M[0647]2 is unnecessary.
• In this case, since the amount of adjustments of the angle of divergence becomes large to the first outgoing beam, it is necessary to use the different optical element from the first angle-of-divergence adjustment component M[0648]1.
• Although the above-mentioned preferred embodiment explained the case where the angle of divergence of the light beam output from each semiconductor laser is adjusted, and incidence is carried out to the coupling lens, it is not limited to this example.[0649]
• When the light beam output from each semiconductor laser has satisfied the upper formula (34), it is not necessary to adjust the angle of divergence.[0650]
• There may not be the first angle-of-divergence adjustment component M[0651]1 and the second angle-of-divergence adjustment component M2.
• Even if it is this case, when rim intensity is greatly shifted from the value made into the ideal, it is possible to adjust the angle of divergence.[0652]
• Although the above-mentioned preferred embodiment explained the case where the wavelength of the light beam output from the light source is the two kinds, the present invention is not limited to this.[0653]
• Although the above-mentioned preferred embodiment explained the case where it comprises the light source which outputs the light beam whose wavelength is 660 nm, and the light source which outputs the light beam whose wavelength is 785 nm, the present invention is not limited to this.[0654]
• For example, it is possible to use the light source which outputs the light beam whose wavelength is 405 nm, instead of one of the two light sources.[0655]
• Although the above-mentioned preferred embodiment explained the case where the hologram is used as a branch optical element for branching the return light beam, it is not limited to this example.[0656]
• For example, it is possible to use the polarization hologram.[0657]
• By this, incidence of the light beam output from each semiconductor laser will be carried out to the[0658]coupling lens52, without the quantity of light almost falling.
• Therefore, high-speed access to the[0659]optical disk15 is attained.
• Moreover, since the amount of the received light in the[0660]photodetector59 increases, the signal level and the S/N ratio of the signal which are outputted from each light-receiving component which constitutes thephotodetector59 can be raised.
• In this case, the phase difference plate for giving optical phase difference like the quarter-wave plate is arranged between the[0661]coupling lens52 and theobject lens60.
• Moreover, it is possible to use the beam splitter instead of the hologram.[0662]
• Although the above-mentioned preferred embodiment explained the case where the light-emission portion EL and the light-receiving portion RL unified, it is not limited to this example.[0663]
• The light-emission portion EL and the light-receiving portion RL may be arranged individually, respectively.[0664]
• Although the above-mentioned preferred embodiment explained the case where each semiconductor laser approached mutually and is arranged, it is not limited to this example.[0665]
• Although the above-mentioned preferred embodiment explained the case where it is the divergence light in which the configuration of the light beam of are outputting from the light source has the optical intensity distribution of the ellipse form, it is not limited to this example.[0666]
• It is possible to be the divergence light in which the configuration of the light beam of are outputting from the light source has the optical, almost circular intensity distribution.[0667]
• Although the case where target rim intensity is 15% is explained by the above-mentioned preferred embodiment when target rim intensity is 30% when the optical disk is DVD, and the optical disk is CD, it is not limited to this example.[0668]
• As for rim intensity, it is desirable that it is 10% or more, and is 70% or less.[0669]
• If the rim intensity exceeds 70%, it will become difficult to secure the required quantity of light.[0670]
• It is for enlarging the numerical aperture of the coupling lens, for considering as less than 10% of rim intensity, and causing the cost rise.[0671]
• In the above-mentioned preferred embodiment, although the light beam output from each semiconductor laser explained the case where the angle of divergence is adjusted and the light beam is incident to the coupling lens so that the optical intensity distribution might serve as the circular configuration mostly, it is not limited to this example.[0672]
• Although the above-mentioned preferred embodiment explained the case where the[0673]hologram61 is one of the composition components of the optical module, it is not limited to this example.
• It may dissociate with the optical module and the[0674]hologram61 may be arranged.
• Without causing enlargement and high cost according to the optical pickup device concerning the present invention, as explained above, it can respond to two or more kinds of information storage mediums, and is effective in the ability to form the optimal optical spot for each information storage medium.[0675]
• According to the optical disk drive concerning the present invention, it can respond to two or more kinds of information storage mediums, and is effective in being stabilized and being able to perform access at the high speed.[0676]
• The composition of the[0677]optical disk drive120 of the preferred embodiment of the present invention is shown in FIG. 47.
• The[0678]optical disk drive120 shown in FIG. 47 comprises thespindle motor22 for carrying out the rotation drive of theoptical disk15 as an information storage medium, theoptical pickup device123, thelaser control circuit24, theencoder25, themotor driver27, the reproductionsignal processing circuit28, theservo controller33, thebuffer RAM34, thebuffer manager37, theinterface38, theROM39, theCPU40, and theRAM41.
• In addition, the arrow in FIG. 47 does not show the flow of the typical signal or information, and does not express connection-related all of each block.[0679]
• The[0680]optical pickup device123 is equipment for receiving the received light from the recording surface of the optical disk while irradiating laser light to the recording surface of the optical disk in which the tracks in the spiral or concentric formation are formed.
• The reproduction[0681]signal processing circuit28 changes into the electrical-potential-difference signal the current signal which is the output signal of theoptical pickup device123, and detects the wobble signal, the RF signal, and the servo signal (the focusing error signal, tracking error signal) based on this electrical-potential-difference signal.
• The reproduction[0682]signal processing circuit28 extracts address information, the synchronizing signal, etc. from the wobble signal.
• The extracted address information is outputted to the[0683]CPU40 and the synchronizing signal is outputted to theencoder25.
• After the reproduction[0684]signal processing circuit28 performs error-correction processing etc. to RF signal, it is stored in thebuffer RAM34 through thebuffer manager37.
• Moreover, the servo signal is outputted to the[0685]servo controller33 from the reproductionsignal processing circuit28.
• The[0686]servo controller33 generates the control signal which controls theoptical pickup device123 based on the servo signal, and outputs it to themotor driver27.
• The[0687]buffer manager37 will notify to theCPU40, if I/O of the data to thebuffer RAM34 is managed and the accumulated amount of data becomes the predetermined value.
• The[0688]motor driver27 controls theoptical pickup device123 and thespindle motor22 based on directions of the control signal from theservo controller33, and theCPU40.
• The[0689]encoder25 takes out the data accumulated at thebuffer RAM34 through thebuffer manager37 based on directions of theCPU40, performs addition of the error correction code etc., and creates the write-in data to theoptical disk15.
• The[0690]encoder25 outputs write-in data to thelaser control circuit24 synchronizing with the synchronizing signal from the reproductionsignal processing circuit28.
• The[0691]laser control circuit24 controls the output of the laser light output from theoptical pickup device123 based on directions of the write-in data from theencoder25, and theCPU40.
• Let one side of the two light sources of the[0692]optical pickup device123 based on directions of theCPU40 be the control object in thelaser control circuit24.
• The[0693]interface38 is the bi-directional communication interface with the host system (for example, a personal computer), and is in conformity with the standards, such as ATAPI (AT Attachment Packet Interface) or SCSI (Small Computer System Interface).
• The program described in code decipherable by the[0694]CPU40 is stored in theROM39.
• The[0695]CPU40 controls operation of each part of the above according to the program stored in theROM39.
• The[0696]CPU40 temporarily stores the data required for control on theRAM41.
• Next, the composition of the above-mentioned[0697]optical pickup device123 will be described with reference to FIG. 48.
• The[0698]optical pickup device123 outputs the light beam whose wavelength is 650 nm, as shown in FIG. 48. It outputs the light beam the firstoptical module151 which receives the return light beam (650 nm return light beam) whose wavelength is 650 nm, and whose wavelength is 780 nm.
• The second[0699]optical module161 receives the return light beam (780 nm return light beam) whose wavelength is 780 nm. Theoptical pickup device123 further includes thefirst hologram153, thesecond hologram156, thebeam splitter154, thecollimator lens152, themicro lens157 as an optical element, thewavelength filter158, theobject lens160, and the drive system (the focusing actuator, the tracking actuator, and seeking motor).
• In addition, the first[0700]optical module151 is chosen when theoptical disk15 is DVD, and the secondoptical module161 is chosen when theoptical disk15 is CD.
• The first[0701]optical module151 containsfirst semiconductor laser151awhich outputs the light beam whose wavelength is 650 nm, and thefirst photodetector151bas a photodetector which receives 650 nm return light beam.
• The second[0702]optical module161 contains thesecond semiconductor laser161aas a light source which outputs the light beam whose wavelength is 780 nm, and thesecond photodetector161bas a photodetector which receives 780 nm return light beam.
• The[0703]first semiconductor laser151ais arranged in the location which acts in the direction of +Z as the outgoing light beam, and thesecond semiconductor laser161ais arranged in the location which acts in the direction of +X as the outgoing light beam.
• The light beam (650 nm outgoing beam) whose wave length output from the[0704]first semiconductor laser151ais 650 nm has the elliptical intensity distribution which makes the perpendicular direction (X axis direction) the direction of the transverse to the activation layer AL1 offirst semiconductor laser151a, as shown in FIG. 49A.
• Moreover, the light beam (780 nm outgoing beam) whose wave length output from the[0705]second semiconductor laser161ais 780 nm has the elliptical intensity distribution which makes the perpendicular direction (Z axis direction) the direction of the transverse to the activation layer AL2 ofsecond semiconductor laser161a, as shown in FIG. 49B.
• The[0706]first hologram153 is arranged on common 650 nm optical path length of the outgoing beam and 650 nm return light beam, and branches 650 nm return light beam in the direction of the light-receiving side offirst photodetector151bfrom the common optical path length.
• The[0707]second hologram156 is arranged on common 780 nm optical path length of the outgoing beam and 780 nm return light beam, and branches 780 nm return light beam in the direction of the light-receiving side ofsecond photodetector161bfrom the common optical path length.
• The[0708]beam splitter154 has high reflectivity to the light beam whose wavelength is 650 nm, comprises the dichroic mirror which has high permeability to the light beam whose wavelength is 780 nm, and is arranged at the light source side of thecollimator lens152.
• The[0709]wavelength filter158 is arranged between thecollimator lens152 and theobject lens160, and specifies the magnitude of the light beam received by theobject lens160 among the light beams output from the semiconductor lasers.
• This[0710]wavelength filter158 includes the three regions (the first region158a, thesecond region158b, and thethird region158c) as shown in FIG. 50.
• The first region[0711]158ais a circular region which is located in a part for the central part of the wave-length filter158, and has diameter φ cd.
• The first region[0712]158ahas high permeability to both the light beams one having the wavelength 650 nm, and the other having the wavelength 780 nm.
• The[0713]second region158bis the region of the shape of a doughnut which touches the periphery of first region158a.
• The[0714]second region158bhas high permeability only to the light beam whose wavelength is 650 nm.
• The[0715]third region158cis a range included by neither the first range158anor thesecond range158b, and has high reflectivity to both the light beams one having the wavelength 650 nm, and the other having the wavelength 780 nm.
• Therefore, the light beam whose wavelength is 650 nm penetrates the inside of the circular range of diameter φ dvd which includes the first range[0716]158aand thesecond range158b, and the light beam whose wavelength is 780 nm penetrates only the inside of first range158a.
• As shown in FIG. 51A, the focal distance of the[0717]collimator lens152 is set up so that the minimum value of RIM in the light beam (650 nm received light beam) Bdvd whose wave length which penetrates the wave-length filter158 and is incorporated by theobject lens160 is 650 nm may become about 30%.
• In this case, when there is no[0718]micro lens157, as shown in FIG. 51B, the minimum value of RIM in the light beam (780 nm received light beam) Bcd whose wavelength which penetrates thewavelength filter158 and is incorporated by theobject lens160 is 780 nm becomes about 40%.
• The[0719]micro lens157 has the convex-lens configuration, is arranged between the secondoptical module161 and thebeam splitter154, and makes small the angle of divergence of 780 nm outgoing beam.
• As shown in FIG. 52, the focal distance and numerical aperture of the[0720]micro lens157 are set up so that the minimum value of RIM in 780 nm received light beam Bcd may become about 13%.
• The aberration compensation of the[0721]object lens160 is carried out to the light beam the light beam whose wave length is 650 nm, and whose wavelength are 780 nm, respectively.
• The arrangement location of the first[0722]optical module151 is optimized so that 650 nm outgoing beam may serve as parallel light by thecollimator lens152.
• Similarly, the second[0723]optical module161 and the arrangement location of themicro lens157 are optimized, respectively so that 780 nm outgoing beam may serve as parallel light by thecollimator lens152.
• The[0724]first photodetector151bandsecond photodetector161bcontain two or more light-receiving components which output the optimal signal for detecting the wobble signal, RF signal, the servo signal, etc. in the reproductionsignal processing circuit28, respectively.
• The action of the[0725]optical pickup device123 constituted as mentioned above is explained.
• First, the case where the[0726]optical disk15 is DVD will be described.
• The light beam which is output in the +Z direction from the[0727]first semiconductor laser151ais incident to thefirst hologram153.
• The light beam through the[0728]first hologram153 is incident to thebeam splitter154.
• After the light beam is reflected in the direction of +X by the[0729]beam splitter154, it is converted into the parallel light beam by thecollimator lens152, and it is incident to thewavelength filter158.
• The light beam through the[0730]wavelength filter158 is focused on the recording surface of the optical disk15 (here DVD) as a minute light spot through theobject lens160.
• After the received light (return light beam) reflected in respect of record of the[0731]optical disk15 is again made into parallel light with theobject lens160 and penetrates the wave-length filter158 and thecollimator lens152, incidence of it is carried out to thebeam splitter154.
• The return light beam reflected in −Z direction by the[0732]beam splitter154 is incident thefirst hologram153.
• The return light beam diffracted by the[0733]first hologram153 is received byfirst photodetector151b.
• Each light-receiving component which constitutes[0734]first photodetector151boutputs the current signal according to the amount of the received light to the reproductionsignal processing circuit28, respectively.
• Next, the case where the[0735]optical disk15 is CD will be described.
• The light beam which is output in the direction of +X from the[0736]second semiconductor laser161ais incident to thesecond hologram156.
• The angle of divergence is reduced by the[0737]micro lens157, and the light beam through thesecond hologram156 is incident to thebeam splitter154.
• After the light beam passes through the[0738]beam splitter154, it is converted into the parallel light beam by thecollimator lens152, and it is incident to thewavelength filter158.
• The light beam through the[0739]wavelength filter158 is focused on the recording surface of the optical disk15 (here CD) as a minute light spot through theobject lens160.
• After the received light beam (return light beam) reflected from the recording surface of the[0740]optical disk15 is again made into the parallel light beam by theobject lens160 and passes through thewavelength filter158 and thecollimator lens152. The light beam is incident to thebeam splitter154.
• The return light beam through the[0741]beam splitter154 is incident to thesecond hologram156 through themicro lens157.
• The return light beam diffracted by the[0742]second hologram156 is received by thesecond photodetector161b.
• Each light-receiving component which constitutes the[0743]second photodetector161boutputs the current signal according to the amount of the received light to the reproductionsignal processing circuit28, respectively.
• It can be distinguished from the intensity of the received light from the recording surface of the optical disk whether the[0744]optical disk15 is CD or DVD.
• Usually, this distinction is performed by the[0745]CPU40 when theoptical disk15 is loaded to the predetermined location of theoptical disk drive120.
• Moreover, it is also possible to distinguish the kind of[0746]optical disk15 based on the TOC (Table Of Contents) information, the PMA (Program Memory Area) information, the wobble signal, etc. which are beforehand recorded on theoptical disk15.
• The distinction result is notified to the[0747]laser control circuit24 from theCPU40, and either the firstoptical module151 and the secondoptical module161 is chosen by thelaser control circuit24.
• Next, processing operation in the case of recording data on the[0748]optical disk15 is briefly explained using the above-mentionedoptical disk drive120.
• Selection of the optical module shall be carried out and shall already have been performed.[0749]
• The[0750]CPU40 notifies the purport that the command of the record request is received from the host system to the reproductionsignal processing circuit28 while outputting the control signal for controlling rotation of thespindle motor22 based on the specified record rate to themotor driver27, if the command of the record request is received from the host system.
• The[0751]CPU40 accumulates the data received from the host system to thebuffer RAM34 through thebuffer manager37.
• If rotation of the[0752]optical disk15 reaches the predetermined linear velocity, the reproductionsignal processing circuit28 will detect the focusing error signal and the tracking error signal based on the output signal from theoptical pickup device123, and will output them to theservo controller33.
• Based on the focusing error signal and tracking error signal from the reproduction[0753]signal processing circuit28, theservo controller33 drives the focusing actuator and tracking actuator of theoptical pickup device123 through themotor driver27, and corrects the focal gap and the track gap.
• The reproduction[0754]signal processing circuit28 acquires address information based on the output signal from theoptical pickup device123, and notifies it to theCPU40.
• The[0755]CPU40 outputs the signal which is specified based on address information and which directs the seeking operation of theoptical pickup device123 that it writes in and theoptical pickup device123 is located in the start point to themotor driver27.
• If the notice that the amount of data accumulated from the[0756]buffer manager37 at thebuffer RAM34 exceeded the predetermined value is received, theCPU40 is written in theencoder25 and directs creation of data.
• Moreover, if the[0757]CPU40 determines that the location of theoptical pickup device123 writes in based on address information, and it is the start point, it will be notified to theencoder25.
• The[0758]encoder25 records write-in data on theoptical disk15 through thelaser control circuit24 and theoptical pickup device123.
• Next, processing operation in the case of reproducing the data currently recorded on the[0759]optical disk15 using theoptical disk drive120 mentioned above is explained briefly.
• Selection of the optical module shall be carried out, and shall already have been performed.[0760]
• The[0761]CPU40 notifies the information that the command of the reproduction request is received from the host system to the reproductionsignal processing circuit28 while outputting the control signal for controlling rotation of thespindle motor22 based on the reproduction rate to themotor driver27, if the command of the reproduction request is received from the host system.
• Like the case of the above-mentioned record, the reproduction[0762]signal processing circuit28 corrects the focal gap and the track gap while notifying address information to theCPU40.
• The[0763]CPU40 outputs the signal which is specified based on address information and which directs the seeking operation that it reads and theoptical pickup device123 is located in the start point to themotor driver27.
• If the[0764]CPU40 determines that the location of theoptical pickup device123 reads based on address information, and it is the start point, it will be notified to the reproductionsignal processing circuit28.
• After the reproduction[0765]signal processing circuit28 detects RF signal based on the output signal of theoptical pickup device123 and performs error-correction processing etc., it is accumulated to thebuffer RAM34.
• The[0766]buffer manager37 transmits to the host system through theinterface38, when the reproduction data accumulated at thebuffer RAM34 are assembled as sector data.
• As mentioned above, the reproduction[0767]signal processing circuit28 detects the focusing error signal and the tracking error signal based on the output signal from theoptical pickup device123, and corrects the focal gap and the track gap at any time through theservo controller33 and themotor driver27, until record processing and the regeneration are completed.
• The processor is realized in the optical disk drive of this preferred embodiment by the program performed by the reproduction[0768]signal processing circuit28, and theCPU40.
• However, the present invention is not limited to this example.[0769]
• It is good also as constituting some processors realized by processing according to the program by the[0770]CPU40 by hardware. Or it is good also as constituting all the processors by hardware.
• As explained above, according to the optical pickup device of this preferred embodiment, the angle of divergence of the light beam output from the[0771]second semiconductor laser161ais made small by themicro lens157 so that the minimum value of RIM in 780 nm received light beam may become about 13%.
• Even if the[0772]collimator lens152 by which wavelength is optimized by this to the light beam which is 650 nm is used, most light beams which are output from thesecond semiconductor laser161awill be incorporated by theobject lens160, and it raises optical efficiency.
• Since the light beam by which incidence is carried out to the[0773]collimator lens152 has the optimal optical intensity distribution for the wavelength, it can secure the optimal RIM for the wavelength in the light beam incorporated by theobject lens160.
• According to the optical pickup device of this preferred embodiment, by the case where they are the case where the[0774]optical disk15 is DVD, and CD, since thecollimator lens152 and theobject lens160 are communalized, the miniaturization of the optical pickup device and low cost are promoted.
• Therefore, according to the optical pickup device of this preferred embodiment, without causing enlargement and high cost, it can respond to two or more kinds of optical disks, and it is possible to form the optimal optical spot for each optical disk on the recording surface thereof.[0775]
• According to the optical disk drive of this preferred embodiment, the optimal optical spot can be formed on the recording surface of each optical disk (DVD and CD), and it is possible to stably perform the high-speed access to each optical disk.[0776]
• When the miniaturization of the optical disk drive itself and reduction of the demand can also be promoted, for example, the optical disk drive is used as portable by the miniaturization of the[0777]optical pickup device123, and lightweight, carrying becomes easy and usable.
• Although the above-mentioned preferred embodiment explained the case where the[0778]micro lens157 is arranged between thebeam splitter154 and thesecond hologram156, it is not limited to this example.
• For example, the[0779]micro lens157 may be arranged between thesecond hologram156 and the secondoptical module161.
• The preferred embodiment of FIG. 53 has the description at the point of changing the angle of divergence of the light beam output from the[0780]first semiconductor laser151aby the micro lens.
• As shown in FIG. 53, instead of the[0781]micro lens157 in the first preferred embodiment of the above, it has the concave-lens configuration and themicro lens162 for enlarging the angle of divergence of the light beam output from thefirst semiconductor laser151ais arranged between thebeam splitter154 and thefirst hologram153.
• Moreover, instead of the above-mentioned[0782]collimator lens152, as shown in FIG. 54B, thecollimator lens163 to which the focal distance is set so that the minimum value of RIM in 780 nm received light beam Bcd might become about 13% is used.
• The composition of the other optical pickup devices and the optical disk drive etc. is the same as that of the above-mentioned preferred embodiment.[0783]
• While explaining focusing on difference with the above-mentioned preferred embodiment below, about the component equivalent to the above-mentioned preferred embodiment, the explanation is omitted using the same sign.[0784]
• In the[0785]collimator lens163, since wave length is optimized to the light beam which is 780 nm, as is shown in FIG. 54A as an example, the minimum value of RIM in 650 nm received light beam Bdvd in case there is nomicro lens162 becomes about 13%.
• As shown in FIG. 55, the focal distance and numerical aperture of the[0786]micro lens162 are set up so that the minimum value of RIM in 650 nm received light beam Bdvd may become about 30%.
• The action of the[0787]optical pickup device123 constituted as mentioned above is explained.
• First, the case where the[0788]optical disk15 is DVD is explained.
• The light beam which is output in the +Z direction from the[0789]first semiconductor laser151ais incident to thefirst hologram153.
• The angle of divergence is enlarged by the[0790]micro lens162, and the light beam through thefirst hologram153 is incident to thebeam splitter154.
• After the light beam is reflected in the direction of +X by the[0791]beam splitter154, it is converted to the parallel light beam by thecollimator lens163, and it is incident to thewavelength filter158.
• The light beam through the[0792]wavelength filter158 is focused on the recording surface of the optical disk.15 (here DVD) as a minute light spot through theobject lens160.
• After the received light (return light beam) is reflected from the recording surface of the[0793]optical disk15, it is again made into the parallel light beam by theobject lens160 and penetrates thewavelength filter158 and thecollimator lens163. It is incident to thebeam splitter154.
• The return light beam reflected in the −Z direction is incident to the[0794]first hologram153 through themicro lens163 by thebeam splitter154.
• The return light beam diffracted by the[0795]first hologram153 is received by thefirst photodetector151b.
• Each light-receiving component which constitutes the[0796]first photodetector151boutputs the current signal according to the amount of the received light to the reproductionsignal processing circuit28, respectively.
• Next, the case where the[0797]optical disk15 is CD will be explained.
• The light beam output in the direction of +X from the[0798]second semiconductor laser161ais incident to thesecond hologram156.
• The light beam through the[0799]second hologram156 is incident to thebeam splitter154.
• After the light beam through the[0800]beam splitter154 is converted into the parallel light beam by thecollimator lens163, it is incident to thewavelength filter158.
• The light beam through the[0801]wavelength filter158 is focused on the recording surface of the optical disk15 (here CD) as a minute light spot through theobject lens160.
• After the received light (return light beam) reflected from the[0802]optical disk15 is again made into the parallel light beam by theobject lens160 and passes through the wave-length filter158 and thecollimator lens163, it is incident to thebeam splitter154.
• The return light beam through the[0803]beam splitter154 is incident to thesecond hologram156.
• The return light beam diffracted by the[0804]second hologram156 is received by thesecond photodetector161b.
• Each light-receiving component which constitutes the[0805]second photodetector161boutputs the current signal according to the amount of the received light to the reproductionsignal processing circuit28, respectively.
• In the[0806]optical disk drive120 of this preferred embodiment, reproduction of the data currently recorded on theoptical disk15 and recording of the data to theoptical disk15 are performed like the above-mentioned preferred embodiment.
• The recording and reproduction processing is realized in the optical disk drive of this preferred embodiment by the program performed by the reproduction[0807]signal processing circuit28 and theCPU40.
• However, the present invention is not limited to this. Alternatively, some of the processing according to the program by the[0808]CPU40 may be realized by the hardware. Or all the processing may be realized by the hardware.
• As explained above, according to the optical pickup device of this preferred embodiment, the[0809]collimator lens163 is optimized to the light beam whose wavelength is 780 nm.
• Moreover, the angle of divergence of the light beam output from the[0810]first semiconductor laser151ais enlarged by themicro lens162 so that the minimum value of RIM in 650 nm received light beam may become 30%.
• The light beam by which incidence is carried out to the[0811]collimator lens163 has the optimal optical intensity distribution for the wavelength.
• In the light beam incorporated by the[0812]object lens160, the optimal RIM for the wavelength is securable.
• Therefore, it is possible to respond to two or more kinds of optical disks, and to form the optimal optical spot for each optical disk on the recording surface thereof without causing enlargement and high cost.[0813]
• According to the optical pickup device of this preferred embodiment, in DVD and CD, since the[0814]collimator lens163 and theobject lens160 are communalized, the miniaturization of the optical pickup device and low cost can be promoted.
• According to the optical disk drive of this preferred embodiment, the optimal optical spot can be formed on the recording surface of each optical disk (CD and DVD). It is possible to acquire the same effectiveness as the optical disk drive of the above-mentioned preferred embodiment.[0815]
• Although this preferred embodiment explained the case where the[0816]micro lens162 is arranged between thebeam splitter154 and thefirst hologram153, it is not limited to this example.
• For example, the[0817]micro lens162 may be arranged between thefirst hologram153 and the firstoptical module151.
• Although the above-mentioned preferred embodiment explained the case where the first[0818]optical module151 andfirst hologram153 are arranged individually, it is not limited to these examples.
• The first[0819]optical module151 andfirst hologram153 may be unified.
• Although similarly the above-mentioned preferred embodiment explained the case where the second[0820]optical module161 andsecond hologram156 are arranged individually, it is not limited to these examples.
• The second[0821]optical module161 andsecond hologram156 may be unified.
• It becomes possible to promote the miniaturization of the optical pickup device.[0822]
• The attachment process and the adjustment process can be simplified and work cost can be reduced.[0823]
• The preferred embodiment of FIG. 56 has the description at the point which unified[0824]first semiconductor laser151aandsecond semiconductor laser161a.
• As shown in FIG. 56, the third[0825]optical module171 with whichfirst semiconductor laser151aandsecond semiconductor laser161ahave been arranged by approaching- mutually is used instead of the firstoptical module151 in the above-mentioned preferred embodiment, and the secondoptical module161.
• And the[0826]third photodetector171bwhich receives 650 nm return light beam and 780 nm return light beam is used instead offirst photodetector151bandsecond photodetector161b.
• The[0827]third photodetector171band themicro lens157 are mounted in the thirdoptical module171.
• It is unified and the[0828]first hologram153 andsecond hologram156 are arranged between thecollimator lens152 and the thirdoptical module171.
• In this preferred embodiment, the[0829]beam splitter154 in the above-mentioned preferred embodiment is unnecessary.
• The composition of the other optical pickup devices and the optical disk drive is the same as that of the above-mentioned preferred embodiment.[0830]
• While explaining focusing on difference with the above-mentioned preferred embodiment below, about the component equivalent to the above-mentioned preferred embodiment, the explanation is omitted using the same sign.[0831]
• First, the action of the[0832]optical pickup device123 is explained about the case where theoptical disk15 is DVD.
• The light beam outgoing in the direction of +X from the[0833]first semiconductor laser151ais incident to thesecond hologram156.
• The light beam through the[0834]second hologram156 is incident to thefirst hologram153.
• After the light beam through the[0835]first hologram153 serves as parallel light by thecollimator lens152, it is incident to thewavelength filter158.
• The light beam through the[0836]wavelength filter158 is focused on the recording surface of the optical disk15 (here DVD) as a minute light spot through theobject lens160.
• After the received light (return light beam) reflected in respect of record of the[0837]optical disk15 is again made into parallel light with theobject lens160 and penetrates the wave-length filter158 and thecollimator lens152, incidence of it is carried out to thefirst hologram153.
• It diffracts by the[0838]first hologram153 and the return light beam through thesecond hologram156 is received bythird photodetector171b.
• Each light-receiving component which constitutes[0839]third photodetector171boutputs the current signal according to the amount of the received light to the reproductionsignal processing circuit28, respectively.
• Next, the case where the[0840]optical disk15 is CD is explained.
• The angle of divergence becomes small by the[0841]micro lens157, and incidence of the light beam come out of and put in the direction of +X from thesecond semiconductor laser161ais carried out to thesecond hologram156.
• The light beam through the[0842]second hologram156 is further incident to thefirst hologram153.
• After the light beam through the[0843]first hologram153 serves as parallel light by thecollimator lens152, it is incident to thewavelength filter158.
• The light beam through the[0844]wavelength filter158 is focused on the recording surface of the optical disk15 (here CD) as a minute light spot through theobject lens160.
• After the received light (return light beam) reflected in respect of record of the[0845]optical disk15 is again made into parallel light with theobject lens160 and penetrates the wave-length filter158 and thecollimator lens152, incidence of it is carried out to thefirst hologram153.
• The return light beam through the[0846]first hologram153 is incident to thesecond hologram156.
• The return light beam diffracted by the[0847]second hologram156 is received by thethird photodetector171b.
• Each light-receiving component which constitutes[0848]third photodetector171boutputs the current signal according to the amount of the received light to the reproductionsignal processing circuit28, respectively.
• In the[0849]optical disk drive120 of this preferred embodiment, reproduction of the data currently recorded on record and theoptical disk15 of the data to theoptical disk15 is performed like the above-mentioned preferred embodiment.
• The processing is realized in the optical disk drive of this preferred embodiment by the program performed by the reproduction[0850]signal processing circuit28 and theCPU40. However, the present invention is not limited to this example.
• Hardware may constitute a part of the processing according to the program by the[0851]CPU40. Or hardware may constitute all the processing.
• As explained above, according to the optical pickup device of this preferred embodiment, the[0852]collimator lens152 optimizes the light beam whose wavelength is 650 nm.
• Moreover, the angle of divergence of the light beam output from the[0853]second semiconductor laser161ais made small by themicro lens157 so that the minimum value of RIM in 780 nm received light beam may become about 13%.
• In DVD and CD, the[0854]collimator lens152 and theobject lens160 are commonized.
• Therefore, it becomes possible to acquire the same effectiveness as the optical pickup device of the above-mentioned preferred embodiment.[0855]
• According to the optical pickup device of this preferred embodiment, since each semiconductor laser is contained and arranged in the same housing, it can promote the miniaturization of the optical pickup device.[0856]
• Since each semiconductor laser is positioned with accuracy sufficient in the case of packaging, it can simplify attachment work and tuning. Low cost is promoted. The stability of the optical spot to mechanical vibration or the temperature change is raised by the light source unit package.[0857]
• According to the optical pickup device of this preferred embodiment,[0858]third photodetector171bis contained in the same housing as each semiconductor laser.
• The miniaturization of the optical pickup device is promoted further.[0859]
• The[0860]third photodetector171band each semiconductor laser are positioned with accuracy sufficient in the case of packaging. Attachment work and tuning are simplified. It becomes possible to promote low cost. The stability of the various signals outputted to the reproductionsignal processing circuit28 by the packaging to mechanical vibration or the temperature change is raised.
• According to the optical disk drive of this preferred embodiment, the optimal light spot can be formed on the recording surface of each optical disk, and it is possible to acquire the same effectiveness as the optical disk drive of the above-mentioned preferred embodiment.[0861]
• Although this preferred embodiment has explained the case where each semiconductor laser is arranged in parallel mutually, and the outgoing directions of the light beams are made the same direction (the direction of +X), it is not limited to this example.[0862]
• For example, as shown in FIG. 57A, while the light-emission point arranges each semiconductor laser in the location which counters mutually, it is possible to use the[0863]optical module172 equipped with triangle-likereflective mirror172awhich reflects the light beam output from each semiconductor laser in the same direction instead of the thirdoptical module171.
• In this example, the light beam which is output in the +Z direction from the[0864]first semiconductor laser151ais reflected in the direction of +X by thereflective mirror172a.
• On the other hand, the angle of divergence becomes small by the[0865]micro lens157, and the light beam which is output in the −Z direction from thesecond semiconductor laser161ais reflected in the direction of +X by thereflective mirror172a.
• In this example, it becomes possible to narrow spacing of the intensity center of 650 nm outgoing beam and the intensity center of 780 nm outgoing beam which carry out incidence to the[0866]collimator lens152.
• The configuration of the optical spot of each wavelength is improvable, respectively.[0867]
• Moreover, as shown in FIG. 57B, the outgoing direction of each semiconductor laser is arranged in the location which intersects perpendicularly mutually, and the light beam which is output from one semiconductor laser may be made to penetrate, and the light beam which is output from the semiconductor laser of another side may use the[0868]optical module173 including thedichroic prism173ato reflect, instead of the thirdoptical module171.
• In this example, the light beam outgoing in the direction of +X from the[0869]first semiconductor laser151apasses through thedichroic prism173a.
• On the other hand, the angle of divergence is reduced by the[0870]micro lens157, and the light beam which is output in the −Z direction from thesecond semiconductor laser161ais reflected in the direction of +X by thedichroic prism173a.
• In this example, it becomes possible to make mostly in agreement the intensity center of 650 nm outgoing beam and the intensity center of 780 nm outgoing beam which carry out incidence to the[0871]collimator lens152.
• The configuration of the optical spot of each wavelength is improvable, respectively.[0872]
• The first reflective film M[0873]1 which reflects alternatively the light beam output from thefirst semiconductor laser151awhen it has further thethird semiconductor laser174awhich outputs the light beam whose wavelength is 400 nm as shown in FIG. 58.
• The[0874]dichroic prism174bincluding the second reflective film M2 which reflects alternatively the light beam output from thefirst semiconductor laser151a, and the light beam output from thesecond semiconductor laser161acan be used.
• The intensity center of the light beam of are outputting from each semiconductor laser can be made mostly in agreement.[0875]
• In this example, it is reflected in −Z direction by the first reflective film M[0876]1, and the light beam come out of and put in the direction of +X from thefirst semiconductor laser151ais reflected in the direction of +X by the second reflective film M2.
• The light beam which is output in the −Z direction from the[0877]second semiconductor laser161apenetrates the first reflective film M1, and is reflected in the direction of +X by the second reflective film M2. The light beam output in the direction of +X from thethird semiconductor laser174apenetrates the second reflective film M2.
• It is possible to make mostly in agreement the intensity center of 400 nm outgoing light beam and the intensity center of 650 nm outgoing light beam which is incident to the[0878]collimator lens152, and the intensity center of 780 nm outgoing light beam.
• The configuration of the optical spot of each wavelength is improvable, respectively.[0879]
• In this case, it is possible to add the micro lens for changing the angle of divergence of the light beam output from the[0880]third semiconductor laser174aif needed.
• It may be made to penetrate without changing the angle of divergence of incoming beams, as shown in FIG. 59A, and it is possible to use the[0881]lens unit175 in which the lens portion LA which has the lens action equivalent to themicro lens157 by etching etc. in the transparent substrate BP of predetermined thickness is formed instead of themicro lens157.
• In this case, incidence of the light beam output from the[0882]first semiconductor laser151ais carried out to the ranges other than the lens portion LA of the lens unit175 (penetration portion), and each semiconductor laser and thelens unit175 are arranged so that incidence of the light beam output from thesecond semiconductor laser161amay be carried out to the lens portion LA of thelens unit175.
• Thereby, the emitting light point spacing L2 of[0883]first semiconductor laser151aandsecond semiconductor laser161aabout Z axis direction becomes possible to make it narrower than the emitting light point spacing L1 (FIG. 59C) at the time of using themicro lens157.
• Moreover, since the[0884]lens unit175 is the configuration where themicro lens157 and the transparent substrate BP which does not influence the angle of divergence of incoming beams are unified, it can raise the workability of the attachment process and the adjustment process, and becomes possible to reduce work cost.
• In addition, the[0885]lens unit175 is easily producible compared with themicro lens157.
• In this preferred embodiment, as shown in FIG. 59B, it is possible to use the[0886]lens unit176 by which the lens portion LB which has the lens action equivalent to themicro lens157 by etching etc. is formed on one field of the transparent substrate BP which does not influence the angle of divergence of incoming beams instead of themicro lens157.
• While arranging the field in which the lens portion LB is formed to the light source side, the light beam output from the[0887]first semiconductor laser151ais incident to the regions other than the lens portion LB of the lens unit176 (penetration portion), and each semiconductor laser and thelens unit176 are arranged so that the light beam output from thesecond semiconductor laser161amay be incident to the lens portion LB of thelens unit176.
• In this case, it becomes possible to make it still narrower than the emitting light point spacing L2 which mentioned above the emitting light point spacing L3 of[0888]first semiconductor laser151aandsecond semiconductor laser161aabout Z axis direction.
• Although this preferred embodiment explained the case where the distance of the light-emission point location of each semiconductor laser and the[0889]collimator lens152 is almost equal, it is not limited to this example.
• The light-emission point location of each semiconductor laser may be mutually shifted about the outgoing direction.[0890]
• For example, the light beam which came out of[0891]second semiconductor laser161a, and is put may not serve as the predetermined divergence light by thecollimator lens152 with the change action of the angle of divergence by themicro lens157, the color aberration of thecollimator lens152, etc.
• In this case, as shown in FIG. 60B, the light-emission point location of[0892]second semiconductor laser161acan be shifted to X axis direction, and let the light beam output from thesecond semiconductor laser161abe the predetermined divergence light by thecollimator lens152.
• Thereby, even if the[0893]optical disk15 is CD, it is stabilized and the optimal optical spot can be formed on the recording surface thereof.
• Moreover, as shown at FIG. 60A in the above-mentioned case, it is possible to use the[0894]lens unit177 instead of themicro lens157.
• The[0895]lens unit177 has the function which makes almost equal the distance Da about X axis direction of the point of the appearance of 650 nm outgoing beam which carries out incidence to thecollimator lens152 emitting light, and the actual light-emission point, and distance Db about X axis direction of the point of the appearance of 780 nm outgoing beam which carries out incidence to thecollimator lens152 emitting light, and the actual light-emission point.
• In the optical pickup device used for the optical disk drive which performs only reproduction of CD, since it is seldom necessary to make optical efficiency high, it may be necessary to change the angle of divergence of the light beam output from the[0896]second semiconductor laser161a.
• In the optical pickup device used for the optical disk drive which records on CD on the other hand, since it is necessary to make optical efficiency high, you have to change the angle of divergence of the light beam output from the[0897]second semiconductor laser161a.
• In this case, after mounting each semiconductor laser in the location optimized in consideration of the color aberration of the[0898]collimator lens152, in the optical pickup device used for the optical disk drive which records on CD, thelens unit177 can be intercalated and attachment accuracy predetermined only by performing positioning of the direction of the optical axis of thecollimator lens152 can be acquired.
• In this case, by the case where the optical pickup device is used for record of CD, and the case where it is used only for reproduction of CD, it becomes possible to mount each semiconductor laser with the same production line, and the manufacturing cost can be reduced.[0899]
• Moreover, it is possible to correct the color aberration of the[0900]collimator lens152 by optimizing the configuration (for example, radius of curvature) and arrangement location of the micro lens instead of shifting the light-emission point location of each semiconductor laser.
• This becomes possible to make mostly the light-emission point location of each semiconductor laser into the equal distance from the[0901]collimator lens152, and the workability at the time of mounting each semiconductor laser improves.
• In this preferred embodiment, the light beam output from the[0902]second semiconductor laser161ais incident to theobject lens160 in response to the influence of the lens system of the two groups of themicro lens157 and thecollimator lens152.
• On the other hand, in response to the influence only of the[0903]collimator lens152, the light beam output from thefirst semiconductor laser151ais incident to theobject lens160.
• Therefore, the allowable error of each arrangement location in the[0904]second semiconductor laser161aand the attachment work of themicro lens157 becomes very small compared with the allowable error of the arrangement location offirst semiconductor laser151a.
• By arranging the[0905]micro lens157 and thecollimator lens152 so that the mutual optical axis may be mostly in agreement, it can consider that the lens system which consists of themicro lens157 and thecollimator lens152 is the one group, and it becomes possible to enlarge the allowable error of the arrangement location ofsecond semiconductor laser161a.
• The attachment process and the adjustment process can be simplified and reduction of work cost is attained.[0906]
• In addition, when the collimator lens is not used, the effectiveness mentioned above can be acquired by making the optical axis of the micro lens, and the optical axis of the object lens mostly in agreement.[0907]
• Although this preferred embodiment explained the case where the third[0908]optical module171 and each hologram are arranged individually, it is not limited to this example.
• The third[0909]optical module171 and each hologram may be unified. Thereby, the miniaturization of the optical pickup device can be promoted.
• Although this preferred embodiment explained the case where each of 650 nm return light beams and 780 nm return light beams is received by[0910]third photodetector171b, it is not limited to this example.
• The photodetector which receives 650 nm return light beam, and the photodetector which receives 780 nm return light beam may be arranged individually, respectively.[0911]
• The required signal should just be outputted from the[0912]optical pickup device123 in the reproductionsignal processing circuit28.
• Although the above-mentioned preferred embodiment explained the case where the focal distance of the[0913]collimator lens152 is set up so that the minimum value of RIM in 650 nm received light beam might become about 30%, it is not limited to this example.
• For example, it is possible to use the collimator lens set up so that the minimum value of RIM in 780 nm received light beam might become about 13%.[0914]
• In this case, the[0915]micro lens163 which enlarges the angle of divergence of the light-beam output from thefirst semiconductor laser151alike the above-mentioned preferred embodiment is used.
• As shown in FIG. 61A, it is possible to use the[0916]lens unit178 in which the lens portion LC which has the lens action equivalent to themicro lens163 by etching etc. in the transparent substrate BP of predetermined thickness which does not influence the angle of divergence of incoming beams is formed instead of themicro lens163.
• Moreover, it is etching etc. to the transparent substrate BP of predetermined thickness which does not influence the angle of divergence of incoming beams as the minimum value of RIM in 650 nm received light beam is 30% or less, and it is shown in FIG. 61B, when using the collimator lens (collimator lens currently optimized by neither 650 nm outgoing beam nor 780 nm outgoing beam) set up so that the minimum value of RIM in 780 nm received light beam might become 13% or more.[0917]
• It is possible to use the[0918]lens unit179 in which the second lens portion LA2 which has the lens action which makes small the firstlens portion LA1 which has the lens action which enlarges the angle of divergence of the light beam output from thefirst semiconductor laser151a, and the angle of divergence of the light beam output from thesecond semiconductor laser161ais formed instead of themicro lens163.
• Although each above-mentioned preferred embodiment explained the case where the semiconductor laser and the photodetector are mounted in the same housing, it is not limited to these examples.[0919]
• The semiconductor laser and the photodetector may be mounted individually, respectively.[0920]
• Although each above-mentioned preferred embodiment explained the case where the non-polarized hologram for which the diffraction efficiency does not depend in the polarization direction of incoming beams, respectively is used as the[0921]first hologram153 and thesecond hologram156, it is not limited to these examples.
• It is possible to use for either [at least] the[0922]first hologram153 or thesecond hologram156 the polarization hologram from which the diffraction efficiency differs by the polarization direction of incoming beams.
• For example, to the polarization direction of the light beam output from the semiconductor laser, the diffraction efficiency is low, and incidence of the light beam output from the semiconductor laser by using the polarization hologram set up so that the diffraction efficiency might become high to the polarization direction of the return light beam is carried out to the[0923]collimator lens152, without the quantity of light almost falling.
• Therefore, access at the high speed to the[0924]optical disk15 is attained.
• Moreover, since the amount of the received light in the photodetector increases, the signal level and the S/N ratio of the signal which are outputted from the photodetector can be raised.[0925]
• In this case, it is necessary to arrange phase difference grant means, such as the quarter-wave plate, between the[0926]collimator lens152 and theobject lens160.
• Instead of either the[0927]first hologram153 or thesecond hologram156, it is possible to use the beam splitter, the polarization beam splitter, etc.
• In each above-mentioned preferred embodiment, it is possible to use the anamorphic lens for the micro lens.[0928]
• For example, in the above-mentioned preferred embodiment, instead of the[0929]micro lens157, as shown in FIG. 62A and FIG. 62B, it is possible to use theanamorphic lens180.
• The configuration of XY cross section of this[0930]anamorphic lens180 is almost the same as themicro lens157, as shown in FIG. 62A.
• As shown in FIG. 62B, unlike the[0931]micro lens157, light with the more large angle of divergence can also incorporate the configuration of XZ cross section.
• The[0932]anamorphic lens180 is designed so that the angle of divergence in the field containing the transverse of the780 outgoing beams and the angle of divergence in the field containing the branch axis may become almost equal,
• As for the light beam incorporated by the[0933]object lens160 among the light beams which came out of thesecond semiconductor laser161a, and are put, as shown in FIG. 62C, compared with the case where themicro lens157 is used, the beam intensity distribution becomes close to the circle configuration, and raises optical efficiency Moreover, the astigmatism can be suppressed by designing theanamorphic lens180 so that the point Pa of the appearance in XY flat surface emitting light and the point Pb of the appearance in XZ flat surface emitting light may turn into the almost same point.
• It is possible to use the lens unit which unified the transparent substrate and the[0934]anamorphic lens180.
• In each above-mentioned preferred embodiment, it is possible to use the diffraction grating and hologram which have the equivalent angle-of-divergence change action instead of the micro lens.[0935]
• For example, since it is cheap and small compared with the micro lens, the diffraction grating promotes the miniaturization of the optical pickup device and the lightweight structure with low cost.[0936]
• Although each above-mentioned preferred embodiment explained the case where the wavelength of the light beam output from the light source is 650 nm and 780 nm, it is not limited to these examples.[0937]
• It is possible to use the light source which outputs the light beam whose wavelength is 400 nm instead of one of the two light sources.[0938]
• Although each above-mentioned preferred embodiment has explained the case where the wavelengthes of the light beams output from the light sources are the two kinds, the present invention is not limited to these examples.[0939]
• Although each above-mentioned preferred embodiment has explained the case where it is the divergence light in which the configuration of the light beam output from the light source has the elliptical intensity distribution, it is not limited to these examples.[0940]
• It is possible to be the divergence light in which the configuration of the light beam output from the light source has the intensity distribution of the circle configuration mostly.[0941]
• Although each above-mentioned preferred embodiment explained the case where the target minimum value of RIM in 650 nm received light beam is 30%, the present invention is not limited to these examples.[0942]
• Moreover, although each above-mentioned preferred embodiment explained the case where the target minimum value of RIM in 780 nm received light beam is 13%, the present invention is not limited to these examples.[0943]
• Without causing enlargement and high cost according to the optical pickup device of the present invention, as explained above, it can respond to two or more kinds of information storage mediums, and the optimal optical spot for each information storage medium can be formed.[0944]
• Moreover, according to the optical disk drive of the present invention, it can respond to two or more kinds of information storage mediums, and it is stabilized and access at the high speed can be performed.[0945]
• The present invention is not limited to the above-described embodiments, and variations and modifications may be made without departing from the scope of the present invention.[0946]
• Further, the present invention is based on Japanese priority applications No. 2002-111544, filed on Apr. 15, 2002; No. 2002-134002, filed on May 9, 2002; No. 2002-134012, filed on May 9, 2002; No. 2002-216446, filed on Jul. 25, 2002; and No. 2002-253737, filed on Aug. 30, 2002, the entire contents of which are hereby incorporated by reference.[0947]

Claims (57)

What is claimed is:

1. A light source unit comprising:

a plurality of light sources outputting light beams respectively, the plurality of light sources being arranged in proximity to each other; and

a divergence-angle changing unit changing an angle of divergence of a light beam output from at least one of the plurality of light sources.

2. The light source unit according toclaim 1 wherein the light beams output from the plurality of light sources have different wavelengths respectively.

3. The light source unit according toclaim 1 wherein the changing unit is provided to change the angle of divergence of the light beam in a predetermined plane including an outgoing direction of the light beam having a maximum intensity.

4. The light source unit according toclaim 1 wherein the changing unit is provided to change respective angles of divergence of two light beams among the light beams output from the plurality of light sources, in two orthogonal planes each including an outgoing direction of one of the two light beams having a maximum intensity.

5. The light source unit according toclaim 1 wherein the changing unit comprises an optical element.

6. The light source unit according toclaim 5 wherein said optical element includes a marking for positioning of said optical element with one of the plurality of light sources.

7. The light source unit according toclaim 5 wherein said optical element includes a marking for positioning of said optical element with said at least one of the plurality of light sources.

8. The light source unit according toclaim 5 wherein said optical element is provided to change an outgoing direction of the light beam having a maximum intensity in addition to the angle of divergence.

9. The light source unit according toclaim 5 wherein said optical element is provided such that astigmatism of said optical element is corrected.

10. The light source unit according toclaim 5 wherein said optical element of the changing unit includes at least one of a positive meniscus lens which reduces the angle of divergence and a negative meniscus lens which enlarges the angle of divergence.

11. The light source unit according toclaim 5 wherein said optical element is provided to change an angle of divergence of a light beam output from a specific one of the plurality of light sources, and said optical element being arranged at a location where the light beams output from the light sources other than the specific light source are not incident to said optical element.

12. The light source unit according toclaim 11 wherein said optical element is arranged at the location so that a distance z from a light-emission point of the specific light source to an outgoing plane of said optical element in a Z-axis direction of an XYZ orthogonal coordinate system with an XY plane being the outgoing plane meets requirement conditions:

d≦z≦(x−φ)/{tan(θ1/2)+tan(θ2/2)}

where x indicates a distance in an X axis direction between the light-emission point of the specific light source and a light-emission point of an adjacent light source in proximity to the specific light source, θ1 indicates an angle of divergence of a first light beam output in the Z axis direction from the specific light source, θ2 indicates an angle of divergence of a second light beam output in the Z axis direction from the adjacent light source, d indicates a thickness in the Z axis direction of the optical element, and ε indicates a width of a region in the x axis direction, the region being interposed between an optical path of the first light beam and an optical path of the second light beam, and neither the first light beam nor the second light beam passing through the region.

13. The light source unit according toclaim 1 wherein the changing unit comprises a plurality of optical elements arranged for the plurality of light sources respectively, and each of the plurality of optical elements changing an angle of divergence of a light beam output from a corresponding one of the plurality of light sources, respectively.

14. The light source unit according toclaim 13 wherein at least two optical elements of the plurality of optical elements are unified.

15. A light source unit package including a light source unit, a branch optical element reflecting a light beam, incident to the light source unit, in a predetermined direction, and a photodetector receiving the reflected light beam from the branch optical element, wherein the light source unit, the branch optical element and the photodetector are unified, and the light source unit comprising:

a plurality of light sources outputting light beams respectively, the plurality of light sources being arranged in proximity to each other; and

a divergence-angle changing unit changing an angle of divergence of a light beam output from at least one of the plurality of light sources.

16. The light source unit package according toclaim 15 wherein the photodetector receives the reflected light beam from the branch optical element without being influenced by the changing unit.

17. An optical element comprising:

a transparent substrate;

a first lens portion provided on the substrate to change an angle of divergence of a first incoming light beam to the optical element; and

a second lens portion provided on the substrate to change an angle of divergence of a second incoming light beam to the optical element.

18. The optical element according toclaim 17 wherein the first lens portion is provided to change the angle of divergence of the first incoming light beam in a first plane including an outgoing direction of the first incoming light beam having a maximum intensity, and the second lens portion is provided to change the angle of divergence of the second incoming light beam in a second plane including an outgoing direction of the second incoming light beam having a maximum intensity.

19. The optical element according toclaim 18 wherein the first plane is orthogonal to the second plane.

20. The optical element according toclaim 17 wherein the first lens portion and the second lens portion are unified.

21. An optical pickup device which focuses a light beam on a recording surface of a corresponding one of two or more storage media of different types and receives a return light beam from the recording surface, the optical pickup device comprising: a light source unit; an optical system which leads the return light beam to a predetermined light-receiving location and includes an object lens focusing each light beam from the light source unit to the recording surface of the corresponding storage medium; and a photodetector arranged at the light-receiving location,

the light source unit comprising:

a plurality of light sources outputting light beams respectively, the plurality of light sources being arranged in proximity to each other; and

a divergence-angle changing unit changing an angle of divergence of a light beam output from at least one of the plurality of light sources.

22. An optical pickup device which focuses a light beam on a recording surface of a corresponding one of two or more storage media of different types and receives a return light beam reflected from the recording surface, the optical pickup device comprising: a light source unit package; and an optical system which leads the return light beam to a predetermined light-receiving location and includes an object lens focusing each light beam from the light source unit package to the recording surface of the corresponding storage medium,

the light source unit package comprising: a light source unit, a branch optical element reflecting a light beam incident to the light source unit, in a predetermined direction, and a photodetector arranged at the light-receiving location and receiving the reflected light beam from the branch optical element, wherein the light source unit, the branch optical element and the photodetector are unified,

the light source unit comprising:

a plurality of light sources outputting light beams respectively, the plurality of light sources being arranged in proximity to each other; and

a divergence-angle changing unit changing an angle of divergence of a light beam output from at least one of the plurality of light sources.

23. An optical disk drive which performs recording, reproduction and erasing of information with a corresponding one of two or more optical disks of different types, the optical disk drive including: an optical pickup device and a reproduction signal processing unit performing reproduction of information based on a signal output by the optical pickup device,

the optical pickup device focusing a light beam on a recording surface of the corresponding optical disk and receiving a return light beam from the recording surface, the optical pickup device comprising: a light source unit; an optical system which leads the return light beam to a predetermined light-receiving location and includes an object lens focusing each light beam from the light source unit to the recording surface of the corresponding storage medium; and a photodetector arranged at the light-receiving location,

the light source unit comprising:

a plurality of light sources outputting light beams respectively, the plurality of light sources being arranged in proximity to each other; and

a divergence-angle changing unit changing an angle of divergence of a light beam output from at least one of the plurality of light sources.

24. An optical pickup device which focuses a light beam on a recording surface of a corresponding one of two or more storage media of different types and receives a return light from the recording surface, the optical pickup device comprising:

a plurality of light sources respectively outputting light beams to the storage media individually, and the respective light beams having different wavelengths;

an optical system which leads the return light beam to a predetermined light-receiving location and includes an object lens and an optical element, the object lens focusing each light beam from the plurality of light source on the recording surface of a corresponding storage medium, and the optical element converting each light beam directed toward the object lens into a parallel light beam; and

a photodetector arranged at the light-receiving location and receiving the return light beam,

wherein each light beam incident to the optical element has an angle of divergence that is inversely proportional to a wavelength of the light beam.

25. The optical pickup device according toclaim 24 wherein each light beam focused with the object lens has a rim intensity that is inversely proportional to a wavelength of the light beam, the rim intensity indicating a ratio of an intensity in a pupil edge of the object lens to a maximum intensity in an entrance pupil of the object lens.

26. The optical pickup device according toclaim 25 wherein the rim intensity is above 10% and below 70%.

27. The optical pickup device according toclaim 24 wherein each light beam output from the plurality of light sources has an angle of divergence that is inversely proportional to a wavelength of the light beam.

28. The optical pickup device according toclaim 24 wherein each light beam output from the plurality of light sources is a divergent light having an intensity distribution in an elliptical cross section of an outgoing direction of the light beam having a maximum intensity, and each light beam has an angle of divergence in a plane including a minor axis of the elliptical cross section, the angle of divergence being inversely proportional to a wavelength of the light beam.

29. The optical pickup device according toclaim 24 wherein the optical system comprises an adjustment optical element which adjusts an angle of divergence of a light beam output from at least one of the plurality of light sources and directed toward the optical element.

30. The optical pickup device according toclaim 29 wherein the adjustment optical element is provided to select a specific wavelength of the light beam with which the angle of divergence is adjusted.

31. The optical pickup device according toclaim 30 wherein the plurality of light sources includes a first light source which outputs a first light beam with a first wavelength and a second light source which outputs a second light beam with a second wavelength longer than the first wavelength.

32. The optical pickup device according toclaim 31 wherein the adjustment optical element includes a first adjustment optical element and a second adjustment optical element which are mutually laminated and unified.

33. The optical pickup device according toclaim 29 wherein the adjustment optical element is provided to change the magnitude of adjustment of the angle of divergence according to an applied voltage.

34. The optical pickup device according toclaim 29 wherein the optical system includes a branch optical element which branches the return light beam, and the adjustment optical element is arranged between the branch optical element and the optical element.

35. An optical disk drive which performs recording, reproduction and erasing of information with a corresponding one of two or more optical disks of different types, the optical disk drive including: an optical pickup device and a reproduction signal processing unit performing reproduction of information based on a signal output by the optical pickup device, the optical pickup device focusing a light beam on a recording surface of the corresponding optical disk and receiving a return light beam from the recording surface, the optical pickup device comprising:

a plurality of light sources respectively outputting light beams to the storage media individually, and the respective light beams having different wavelengths;

an optical system which leads the return light beam to a predetermined light-receiving location and includes an object lens and an optical element, the object lens focusing each light beam from the plurality of light source on the recording surface of a corresponding storage medium, and the optical element converting each light beam directed toward the object lens into a parallel light beam; and

a photodetector arranged at the light-receiving location and receiving the return light beam,

wherein each light beam incident to the optical element has an angle of divergence that is inversely proportional to a wavelength of the light beam.

36. An optical pickup device which focuses a light beam on a recording surface of a corresponding one of two or more storage media of different types and receives a return light from the is recording surface, the optical pickup device comprising:

a plurality of light sources respectively outputting light beams to the storage media individually, and the respective light beams having different wavelengths;

an optical system which leads the return light beam to a predetermined light-receiving location and includes an object lens and an optical element, the object lens focusing each light beam from the plurality of light source on the recording surface of a corresponding storage medium, and the optical element changing an angle of divergence of a light beam output from at least one of the plurality of light sources and directed toward the object lens; and

a photodetector arranged at the light-receiving location and receiving the return light beam.

37. The optical pickup device according toclaim 36 wherein each light beam focused with the object lens has a rim intensity that is inversely proportional to a wavelength of the light beam, the rim intensity indicating a ratio of an intensity in a pupil edge of the object lens to a maximum intensity in an entrance pupil of the object lens.

38. The optical pickup device according toclaim 37 wherein the rim intensity is above 10% and below 70%.

39. The optical pickup device according toclaim 36 wherein each light beam output from the plurality of light sources has an angle of divergence that is inversely proportional to a wavelength of the light beam.

40. The optical pickup device according toclaim 36 wherein each light beam output from the plurality of light sources is a divergent light having an intensity distribution in an elliptical cross section of an outgoing direction of the light beam having a maximum intensity, and each light beam has an angle of divergence in a plane including a minor axis of the elliptical cross section, the angle of divergence being inversely proportional to a wavelength of the light beam.

41. The optical pickup device according toclaim 36 wherein the optical system comprises an adjustment optical element which adjusts an angle of divergence of a light beam output from at least one of the plurality of light sources and directed toward the optical element.

42. The optical pickup device according toclaim 41 wherein the adjustment optical element is provided to select a specific wavelength of the light beam with which the angle of divergence is adjusted.

43. The optical pickup device according toclaim 42 wherein the plurality of light sources includes a first light source which outputs a first light beam with a first wavelength and a second light source which outputs a second light beam with a second wavelength longer than the first wavelength.

44. The optical pickup device according toclaim 43 wherein the adjustment optical element includes a first adjustment optical element and a second adjustment optical element which are mutually laminated and unified.

45. The optical pickup device according toclaim 41 wherein the adjustment optical element is provided to change the magnitude of adjustment of the angle of divergence according to an applied voltage.

46. The optical pickup device according toclaim 41 wherein the optical system includes a branch optical element which branches the return light beam, and the adjustment optical element is arranged between the branch optical element and the optical element.

47. The optical pickup device according toclaim 36 wherein each light beam incident to the optical element has an angle of divergence that is inversely proportional to a wavelength of the light beam.

48. A method of manufacture of an optical pickup device which has a plurality of light sources including a first light source and a second light source arranged in proximity, while leading each light beam which are outputs the angle of divergence of each light beam output from the first and the second light source from each light source including the optical element adjusted, respectively to the recording surface of the corresponding optical disk, comprising the steps of:

acquiring information about an outgoing direction of each light beam which is output from the first and second light sources passes through the optical element, respectively; and

compensating for the outgoing direction of each light beam by correcting a location of the optical element based on the acquired information about the outgoing direction.

49. The method of manufacture according toclaim 48 further comprising the step of arranging the optical element for converting the light beam into a parallel light beam in an optical path of the light beam through the optical element.

50. The method of manufacture according toclaim 48 wherein the first light source and the second light source are set in ON state to emit the light beams simultaneously in the acquisition step.

51. The method of manufacture according toclaim 50 wherein the light beam output from first light source has an intensity different from an intensity of the light beam output from the second light source in the acquisition process.

52. The method of manufacture according toclaim 50 further comprising the step of arranging a first filter which converts the light beam output from the first light source, or a second filter which converts the light beam output from the second light source.

53. The method of manufacture according toclaim 48 wherein a photodetector which detects at the light-receiving location the light beam through the optical element is used in the acquisition step.

54. The method of manufacture according toclaim 50 wherein the light beam output from the first light source is reflected by a branch optical element which reflects the light beam output from the second light source is arranged on the optical path of the light beam through the optical element.

55. The method of manufacture according toclaim 48 wherein the first and the second light sources output each light beam one by one in the acquisition step.

56. The method of manufacture according toclaim 48 further comprising the step of displaying the information about the outgoing direction acquired in the acquisition step.

57. The method of manufacture according toclaim 48 wherein the optical element is a meniscus lens.

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