US20070097021A1 - Information processing device - Google Patents

Abstract

There is provided an information processing apparatus which occupies a small space and which is capable of supplying image information having high definition and high resolution. An information processing apparatus of the invention employs a head mount display (HMD) utilizing compact flat panel displays as a display device for displaying information. The use of a head mount display as the display device of the information processing apparatus prevents any reduction in a work space. It also makes it possible to change the size of a virtual display screen freely. In addition, the information processing apparatus of the invention is capable of displaying a plurality of pieces of information on the virtual display screen at a time.

Description

BACKGROUND OF THE INVENTION
• 1. Field of the Invention:
• The presents invention relates to an information processing device and a system utilizing a head mount display (HMD).
• 2. Description of the Related Art:
• Users who deal with electronic information have carried out information processing operations using an information processing apparatus as schematically shown inFIG. 20. In the context of this specification, “information processing operation” means input, acquisition, transmission, exchange, storage, administration and the like of information carried out using a computer or the like.
• An input terminal2001 which is a keyboard, mouse or the like is a device to allow a user to perform an operation of inputting information. Acontroller2002 such as a computer connected to the input terminal2001 is a device to perform processes such as storage, calculation and communication of information. Adisplay device2003 such as a CRT is a device for outputting information and displaying the same as an image.
• In a conventional information processing apparatus, adisplay device2003 such as a CRT occupies a large part of a space on a work desk on which the information processing apparatus is operated. Further, the recent increase in the amount of information (characters, images and the like) has resulted in a need for displaying a plurality of pieces of information at a time.
• In order to recognize a plurality of pieces of information with reliability, attempts have been made to increase the size of the screens of display devices. However, the volume and weight of a conventional display device such as a CRT have become considerably large with an increase in the screen size, which has made the display device unsuitable for daily use. Further, continued use for a long period of time has been avoided because it has bad influence on human eyes (fatigue, amblyopia and the like).
• This has resulted in the spread of flat panel display devices whose bodies are smaller in depth and lighter than those of CRTs. Especially, products utilizing a liquid crystal panel are widely used among such flat panel displays.
• Compact liquid crystal panels are portable because they are very light. Liquid crystal panels are advantageous also in that they have less influence on human eyes compared to CRTs. However, they are expensive as display devices for daily use when they are in large screen sizes because they suffer from bad yield of production.
• Although flat panel displays such as liquid crystal displays have recently come in practice to replace CRTs as described above, a display of an information processing apparatus still occupies a large part of a space on a work desk.
• The present invention has been conceived taking the above-described problem into consideration, and it is an object of the present invention to provide a novel information processing apparatus in which the above-describe problem is solved.
SUMMARY OF THE INVENTION
• In an information processing apparatus (device) according to the present invention, a head mount display (HMD) utilizing a compact flat panel display (typically a liquid crystal display) is used as a display for displaying information. The use of a head mount display as a display device for an information processing apparatus makes it possible to solve the problem of the size of a display device encountered in the prior art. A head mount display is advantageous in that it does not reduce an operating space because it is mounted on an operator's head during use and in that the size of a virtual display screen thereof can be freely changed.
• A head mount display (HMD) displays an image in a position a few centimeters ahead the user's eyes using an optical system to cause the user's eyes to recognize the image with a sense of virtual reality as if it is displayed on a large display device.
• An HMD used in an information processing apparatus according to the present invention has high resolution unlike those in the prior art which have low display resolution, can be driven at a high speed and can display a plurality of pieces of information on a virtual display screen thereof.
• Since conventional HMDs have had low resolution, it has been difficult in practice to recognize characters with them. Further, conventional HMDs give fatigue of a considerable degree when used a few hours continuously. In addition, they can result in symptoms that resemble car sickness. Therefore, they are unsuitable as display devices for information processing apparatuses. It is believed that such problems with conventional HMDs can adversely affect eyes and are very much serious from the viewpoint of health.
• One of the most significant problems of HMDs is flickers in images provided by HMDs. Such flickers in images are caused by alternating driving performed to prevent the deterioration of liquid crystal materials and to maintain the quality of display. When the inversion period of the positive and negative polarities of a voltage applied to each pixel (inversion period) is in a frequency band which is visible to human eyes (on the order of about 30 Hz), a flicker is visually recognized as a result of a slight difference between a display from an image signal that appears when the signal has the positive polarity and a display that appears when the signal has the negative polarity.
• An HMD utilizing a liquid crystal panel having high definition and resolution will have a very high driving frequency. For example, the NTSC and HDTV standards specify required numbers of pixels of about 400,000 and about 2,000,000, respectively. Therefore, the maximum frequency of an input image signal is at about 6 MHz according to the NTSC standard and is in the range from about 20 MHz to about 30 MHz according to the HDTV standard. In order to display such an image signal accurately, a clock signal is required which is at a frequency several times higher than that of the image signal (e.g., within the range from about 50 MHz to about 60 MHz).
• In a conventional HMD, it has been difficult to drive the liquid crystal display by accurately alternating such an image signal and clock signal having a high frequency band. The reason is that it has been impossible to manufacture thin film transistors (TFTs) that can accurately operate in such a high frequency from amorphous silicon or polycrystalline silicon.
• When an image signal having a dot clock at a very high speed is to be displayed, conventional TFTs have had in a problem in that inaccurate display results from phase shift, noises, the rounding of a signal waveform and the like because periods for writing the image signal in display pixels become short.
• An HMD used in an information processing apparatus according to the present invention utilizes TFTs that can be driven at a high speed in a liquid crystal panel incorporated therein. This makes it possible to provide an HMD having high definition and resolution that is free from flickers in images.
• Configurations of an information processing apparatus according to the present invention will now be described.
• According to an embodiment of the present invention, there is provided an information processing apparatus characterized in that it comprises:
• a display device having flat panel displays for right and left eyes mounted on the head of a user;
• a controller connected to the display device; and
• an input operation device connected to the controller and in that the flat panel displays are capable of displaying a plurality of pieces of information at a time. Thus, the above-described object is achieved.
• According to another embodiment of the invention, there is provided an information processing apparatus characterized in that it comprises:
• a display device having flat panel displays for right and left eyes mounted on the head of a user;
• a controller; and
• an input operation device connected to the controller, in that controller transmits a signal in the form of an electric wave to the display device and in that the flat panel displays are capable of displaying a plurality of pieces of information at a time. The above-described object is thus achieved.
• According to still another embodiment of the invention, there is provided an information processing apparatus characterized in that it comprises:
• a display device having flat panel displays for right and left eyes mounted on the head of a user;
• a controller;
• an image pick-up device; and
• an input operation device connected to the controller, in that controller transmits a signal in the form of an electric wave to the display device, in that the image pick-up device converts at least images of the input operation device and a hand of the user into electrical signals and supplies the electrical signals to the controller and in that the flat panel displays display a plurality of pieces of information including at least the images of the input operation device and the hand of the user at a time. The above-described object is thus achieved.
• Channel formation regions of TFTs connected to pixel electrodes of the flat panel displays of the display device may be constituted by a semiconductor thin film formed by a collection of a plurality of bar-shaped or planar bar-shaped crystals formed on an insulating surface.
• The plane of the channel formation regions may be oriented substantially in a {110}-direction.
• In grain boundaries in the channel formation regions, 90% or more of the crystal lattices may have continuity.
• The flat panel displays may have a display device on which one screen is written at frequencies in the range from 30 Hz to 180 Hz and on which screen display is carried out with the polarity of the voltage applied to the pixel electrodes inverted for each screen.
• The flat panel display may have a display device which is a liquid crystal display using a liquid crystal material which is antiferroelectric liquid crystals or ferroelectric liquid crystals substantially having no threshold.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a schematic view of an embodiment of an information processing apparatus according to the present invention.
• FIG. 2 illustrates a virtual display screen of the information processing apparatus according to the present invention.
• FIGS. 3A and 3B show examples of the head mount display used in the information processing apparatus according to the present invention.
• FIG. 4 is a schematic view of a liquid crystal panel incorporated in a head mount display used in an information processing apparatus according to the present invention.
• FIG. 5 illustrates a circuit configuration of a liquid crystal panel incorporated in a head mount display used in an information processing apparatus according to the present invention.
• FIG. 6 is a schematic view of another embodiment of an information processing apparatus according to the present invention.
• FIG. 7 is a schematic view of still another embodiment of an information processing apparatus according to the present invention.
• FIG. 8 illustrates a virtual display screen of an information processing apparatus according to the present invention.
• FIG. 9 is a schematic view of still another embodiment of an information processing apparatus according to the present invention.
• FIG. 10 is a schematic view of still another embodiment of an information processing apparatus according to the present invention.
• FIG. 11 is a schematic view of still another embodiment of an information processing apparatus according to the present invention.
• FIG. 12 illustrates a virtual display screen of an information processing apparatus according the present invention.
• FIGS. 13A through 13D show an example of steps for fabricating a liquid crystal panel incorporated in a head mount display used in an information processing apparatus according to the present invention.
• FIG. 14 shows an example of a structure of a liquid crystal display incorporated in a head mount display used in an information processing apparatus according to the present invention.
• FIG. 15 is a perspective view of a liquid crystal panel incorporated in a head mount display used in an information processing apparatus according to the present invention.
• FIG. 16 shows a TEM photograph of CGS.
• FIG. 17 shows a TEM photograph of high temperature polysilicon.
• FIGS. 18A and 18B show electron beam diffraction patterns in CGS and high temperature polysilicon, respectively.
• FIGS. 19A and 19B show TEM photographs of CGS and high temperature polysilicon, respectively.
• FIG. 20 is a schematic view of a conventional information processing apparatus.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
• FIG. 1 is a schematic view of an information processing apparatus according to the present invention. With the information processing apparatus according to the invention, auser100 can perform information processing operations using aninput terminal101 and acontroller102 while watching avirtual display screen104 with a display device (head mount display (HMD))103 mounted on his or her head.
• The display device (HMD)103 used in the information processing apparatus according to the invention can provide display with high definition and resolution. As a result, a plurality of pieces of information can be displayed at a time on thevirtual display screen104 observed by theuser100 as shown inFIG. 2.FIG. 2 shows thevirtual display screen104. As shown inFIG. 2, thevirtual display screen104 shows various pieces of information on a plurality ofwindow screens201 through203.
• Flat panel displays for right and left eyes are incorporated in thedisplay device103 used in the information processing apparatus of the invention. This is not to limit the present invention, and it is possible to use any display device incorporating flat panel displays for right and left eyes which can be mounted on the head of a user to provide a virtual display screen (a display screen for two-dimensional images or three-dimensional images) having resolution at which characters can be recognized.
• The flat panel displays used as the display device used in the information processing apparatus of the invention may be flat panel displays in which the semiconductor films for the switching elements are formed from continuous grain silicon (CGS).
• The display device used in the information processing apparatus of the present invention is driven using frame inversion driving wherein the positive and negative polarities of a voltage applied to all pixels are inverted for each frame (screen) at a frequency band (about 30 Hz or more) which is invisible to human eyes even if the distance between the flat panel displays and the eyes is as small as a few centimeters. There is no limitation on the flat panel displays incorporated in the display device used in the information processing apparatus according to the present invention as long as they are liquid crystal panels which perform line sequential scanning of pixel TFTs and which use A.C. drives (alternating drives) at a frequency band (about 30 Hz or more) which is invisible to human eyes.
• There is no limitation on theinput terminal101 of the information processing apparatus according to the present invention as long as it is a device with which a user can input information to the controller. Typical devices include keyboards, mice, controllers, cameras and microphones.
• There is no limitation on thecontroller102 as long as it is a device which includes at least means for receiving information from the input terminal, means for storing electronic information and means for transmitting image information to the display device.
• Wiring using electrical cords and optical fibers may be used as the means for inputting information to the controller and the means for transmitting image information to the display device. Further, a cordless configuration may be employed wherein information is transmitted in the form of light or electric waves.
• While several embodiments of the present invention will be described below, the information processing apparatus of the invention is not limited to those embodiments.
• A first embodiment of the present invention will now be described.
• FIG. 1 is a schematic view of an information processing apparatus of the present invention.FIG. 2 shows avirtual display screen104.FIGS. 3A and 3B show the appearance of display devices (head mount displays)103. Thedisplay devices103 of the present embodiment display 2D (two-dimensional) images.
• As shown inFIG. 1, thedisplay103 is electrically connected to aninput terminal101 and a controller102 (computer or the like). Those elements collectively form an information processing apparatus and an information processing system.
• FIG. 2 also shows avirtual display screen104. As shown inFIG. 2, various pieces of information such as a plurality ofwindow screens201 through203 are displayed on thevirtual display screen104.
• FIGS. 3A and 3B show display devices (head mount displays)103. Referring toFIG. 3A, theHMD104 has a configuration including aband303 for fixing amain body201 on a head and two active matrix type compactliquid crystal panels302 in a dimension in the range from 0.2 to 2.6 inches for displaying images. In the present embodiment, transmission type active matrix liquid crystal panels of 1.4 inches are used.FIG. 3B shows adisplay device104 which feels like eyeglasses or sunglasses when worn.
• Oneliquid crystal panel302 or305 is provided for each of right and left eyes of a user. Referring to the arrangement of theliquid crystal panels302 or305, in addition to the configuration shown inFIG. 2, a configuration may be employed in which an image which has been optically modulated by theliquid crystal panels302 or305 is projected upon a mirror or a half mirror to be viewed by the user. In this case, theliquid crystal panels302 or305 are also provided on amain body301 or304, respectively. The optical system used in the present embodiment has the same functions as those in the prior art.
• While transmission type active matrix liquid crystal panels are used as theliquid crystal panels302 and305 of the present embodiment, reflection type active matrix liquid crystal panels may be used instead.
• Further, an optical system (concave half mirror or the like) may be provided in themain body201 to increase the size of an image for virtual display. In this case, diffusers (diffusing plates) are preferably provided in front of the liquid crystal panels to eliminate roughness from a magnified image. It is possible to employ a configuration including a back light, a configuration having a function of adjusting the eye gap and a configuration in which an acoustic device is incorporated in themain body301 or304.
• The liquid crystal panels described in the present embodiment have a configuration including color filters for forming a color image on an RGB (red, green and blue) basis. The primary colors required for color display are not limited to them, and appropriate colors may be set.
• A configuration may also be employed in which red (R), green (G) and blue (B) light emitting diodes are used as back lights incorporated in themain body301 or304 to provide color images. In this case, each of the R, G and B light emitting diodes is blinked such that they are repeated in a sequence of R, G, B, R, G, B, R, in a time series at a frequency which is three times the writing period for one screen (frame frequency), which causes human eyes to recognize a color image. In this case, since no color filter is needed, bright display can be achieved.
• In the configuration described in the present embodiment, the structure of the two liquid crystal display panels indicated by302 or305, especially the structure associated with the arrangement of pixels is as shown inFIG. 4. The size of the pixels is preferably in the range from 4 μm×4 μm to 45 μm×30 μm. In the present embodiment, the pixel size is 28 μm×28 μm. The pixels inactive matrix regions403 and406 are preferably defined such that they occupy a small area to improve the numerical aperture.
• InFIG. 4, 407 designates a substrate (glass substrate or quartz substrate) for the liquid crystal panel for the left eye.Peripheral driving circuits401 and402 are provided on thesubstrate407. Further, the pixel matrix region (active matrix region)403 is provided.
• 408 designates a substrate (glass substrate or quartz substrate) for the liquid crystal panel for the right eye.Peripheral driving circuits404 and405 are provided on thesubstrate408. Further, the pixel matrix region (active matrix region)406 is provided.
• The two liquid crystal panels413 (for the left eye) and414 (for the right eye) correspond to theliquid crystal panels302 and305 inFIGS. 3A and 3B.
• In the active matrix region, gate signal lines (scan lines)409 andsource signal lines410 are provided in the form of a grid, andpixel TFTs411 are provided in the vicinity of intersections thereof. A structure is employed in which apixel TFT411 controls the amount of charge maintained at apixel electrode412 to control the intensity of light transmitted through the liquid crystal layer, thereby providing an image on the liquid crystal panel as a whole in combination with other pixels.
• The peripheral driving circuits of the left and right liquid crystal displays are arranged in line symmetry about anaxis400 extending therebetween. In general, theaxis400 substantially coincides with a line which vertically extends in the middle of the face of a user to divide it in two.
• This makes it possible to establish symmetry between the apparent structure of the right-hand side liquid crystal panel as viewed by the right eye and the apparent structure of the left-hand side liquid crystal panel as viewed by the left eye. It is also possible to arrange the liquid crystal panels in symmetry about an axis of symmetry300.
• This is important in maintaining the balance of the structure. This is important especially in a head mount display in which the liquid crystal panels are located close to the eyes of a user.
• FIG. 5 shows an example of an internal block diagram of thedisplay device103. Thedisplay device103 includesliquid crystal controllers501L and501R, atiming generation circuit503 and the like.
• Thetiming generation circuit503 forms a synchronization signal such as a clock signal for adjusting the timing of display. In the present embodiment, an external device (controller or the like) performs a process of separating the signal into two to form signals for the left and rightliquid crystal panels413 and414. Theliquid crystal controllers501L and501R primarily performs a process of converting signals from the outside (a controller (a computer or the like) and image information signals from a storage device (an magneto-optical storage medium, magnetic storage medium or the like) that stores images, a television tuner and the like into signals which can be displayed on the left and rightliquid crystal panels413 and414. The order of the signal processing in thedisplay device103 may be appropriately changed depending on the circuit design.
• A lighter weight and a higher level of integration can be achieved by forming theliquid crystal controllers501L and501R and thetiming generation circuit503 on the same substrate as peripheral circuits of the liquid crystal panels.
• A configuration may also be employed in which thedisplay device103 has a function of shutting out information on the state of the environment and a function of displaying virtual screens in an overlapping relationship with the surrounding scenery. A user can concentrate on virtual display screens by shutting out the state of the environment during an information processing operation. He or she can relax because of isolation from the environment. obviously, a configuration is preferred in which both of the above-described functions are provided along with a switching device that allows a user to freely switch them. Further, a configuration may be employed in which the display device is provided with a function of automatically switching in accordance with an image signal input thereto.
• The method for image display in the present invention is the same for animage signal502R for the right eye and animage signal502L for the left eye because a 2D (two-dimensional) image is to be displayed.
• The liquid crystal panels (theliquid crystal panel414 for the right eye and theliquid crystal panel413 for the left eye) used in thedisplay device103 according to the invention performs line sequential scanning of the pixel TFTs, and the number of the pixels is so enormous as to be compatible with ATVs (advanced televisions) in the future. Therefore, they have resolution equal to or higher than that in the XGA mode, e.g., 1920 (horizontal)×1280 (vertical). The display device used in the information processing apparatus according to the invention is not limited to this resolution.
• Thedisplay device103 of the invention is driven using frame inversion driving wherein the positive and negative polarities of a voltage applied to all pixels are inverted for each frame (screen) at a frequency band (about 60 Hz or more) which is invisible to human eyes even if the distance between theliquid crystal panels413 and414 and the eyes is as small as a few centimeters. In the present embodiment, the positive and negative polarities of a voltage applied to all pixels are inverted for each frame (screen) at a frequency of 60 Hz. Alternatively, it may be driven using source line inversion driving wherein the positive and negative polarities of a voltage applied to pixels are inverted for each source line.
• A description will now be described on an example of a method for fabricating the liquid crystal panels used in the information processing apparatus of the present embodiment. The method for fabricating liquid crystal panels described below is merely an example and the method for fabricating the liquid crystal panels used in the information processing apparatus of the present embodiment is not limited thereto.
• The present embodiment refers to an example of a method for integrating an active matrix region and peripheral driving circuits on one glass substrate or quartz substrate and fabricating a liquid crystal panel with reference toFIGS. 13A and 13B.
• As shown inFIG. 13A, asilicon oxide film1302 as an underlying film is formed on an insulatingsubstrate1301 to a thickness of 3000 Å using a sputtering process.
• Next, an amorphous silicon film (not shown) is formed to a thickness of 400 Å using a low pressure thermal CVD process. Further, this amorphous silicon film is crystallized to obtain a crystalline silicon film referred to as “continuous grain silicon (CGS)”. A method for fabricating CGS will be described later. The crystalline silicon film is patterned to form the island-shaped semiconductor layers indicated by1303,1304 and1305 inFIG. 13A.
• The island-shaped semiconductor layers become the active layers of thin film transistors. The region indicated by1303 becomes the active layer of an NMOS (N-channel type thin film MOS transistor) that forms a part of a CMOS circuit in a peripheral driving circuit.
• The region indicated by1304 becomes the active layer of a PMOS (P-channel type thin film MOS transistor) that forms a part of a CMOS circuit in a peripheral driving circuit.
• The region indicated by1305 become the active layer of an NMOS (N-channel type thin film MOS transistor) provided at a pixel.
• The state shown inFIG. 13A is thus achieved. A pattern of a gate electrode is formed from aluminum.
• First, a aluminum film including 0.18 percent by weight of scandium is formed to a thickness of 4000 Å using a sputtering process. Scandium is included here in order to prevent the formation of protrusions such as hillocks and whiskers attributable to abnormal growth of aluminum at a subsequent step.
• After the aluminum film is formed, an anodic oxide film having dense film quality (not shown) is formed on the surface thereof to a thickness on the order of 100 Å.
• The electrolytic solution used here is an ethylene glycol solution including 3% tartaric acid neutralized by ammonia water. An anodic oxide film can be formed on the surface of the aluminum film by applying a current between platinum as a cathode and aluminum as an anode in the electrolytic solution.
• This anodic oxide film has dense and rigid film quality and has a function of improving adhesion between a resist mask to be formed later and the aluminum film. The thickness of the anodic oxide film can be generally controlled by a voltage applied thereto.
• When the aluminum film (not shown) having an anodic oxide film (not shown) formed thereon is provided, a resist mask is formed on the surface thereof to perform patterning using the mask. As a result, gate electrode patterns indicated by1307,1308 and1309 inFIG. 13B are provided.
• When the gate electrode patterns indicated by1307,1308 and1309 are provided, anodic oxide films are formed again. The anodic oxide films are also formed using an ethylene glycol solution including 3% tartaric acid neutralized with ammonia water.
• Here, the thickness of theanodic oxide films1310,1311 and1312 is 1000 Å. The anodic oxide films have a function of protecting the surface of the gate electrodes formed from aluminum electrically and physically.
• Next, doping is carried out with impurities that provide a conductivity type using the gate electrodes and the anodic oxide films on the surface thereof as a mask. At this step, doping with P (phosphorus) and B (boron) is alternately and selectively carried out using a plasma doping process with resist masks applied selectively to form N-type regions1313,1316,1321 and1324. P-type regions1317 and1320 are also formed.1314,1318 and1322 represent low-concentration impurity regions.
• After the doping is completed, the impurities used for doping are irradiated with laser beams to activate the same and to anneal damage that has occurred during doping.1313 represents the source region of an NMOS;1316 represents the drain region of the NMOS;1317 represents the drain region of a PMOS; and1320 represents the source region of the PMOS.1321 represents the drain region of an NMOS, and1324 represents the source region of the NMOS.1315,1319 and1323 represent the channel formation regions of the respective thin film transistors.
• The state shown inFIG. 13B is thus achieved. Then, asilicon nitride film1325 to constitute a layer insulation film is formed to a thickness of 2000 Å using a plasma CVD process (FIG. 13C).
• The state shown inFIG. 13C is thus realized. Then, contact holes are formed to formelectrodes1326 through1330 constituted by multi-layer films comprising a titanium film, an aluminum film and another titanium film.
• The thickness of the titanium films is 1000 Å, and the thickness of the aluminum film is 2000 Å. Each of the films is formed using a sputtering process.
• At this point, a CMOS circuit that constitutes a peripheral driving circuit is formed.
• Further, a spin coating process is performed to form afilm1331 made of polyimide resin that constitutes a first layer insulation film. Polyamide, polyimideamide, or the like may be used instead of polyimide resin. A resin material is used for the layer insulation film because it allows the surface to be planarized.
• The state shown inFIG. 13C is thus realized. Next, a black matrix made of titanium is formed.
• Next, a secondlayer insulation film1333 made of polyimide resin is formed. Then, contact holes are formed to formpixel electrodes1334 made of ITO.
• The state shown inFIG. 13D is thus realized. When the state shown inFIG. 13D is realized, a heating process is performed for one hour in a hydrogen atmosphere at 350° C. In this manner, a TFT is formed.
• While the gate electrodes are formed from aluminum in the present embodiment, silicon may be used for the gate electrodes.
• While the present embodiment has referred to an example of top-gate type TFTs, a configuration using bottom-gate type TFTs may be employed.FIG. 14 shows an example of a structure of a bottom-gate type TFT in which1401 represents a substrate;1402 represents an underlying film,1403 represents a gate electrode;1404 represents a gate insulation film;1405 represents a source region;1406 represents a drain region;1407 represents an LDD region;1408 represents a channel formation region;1409 represents a channel protection film;1410 represents a layer insulation film;1411 represents a source electrode; and1412 represents a drain electrode.
• When a TFT is to have a bottom-gate type structure, thechannel formation region1408 is similarly formed using a continuous grain silicon film referred to as “CGS”.
• Referring now toFIG. 15, a plurality of TFTs formed of CGS constitute apixel matrix circuit1503, a gate-side driving circuit1504, a source-side driving circuit1505 and a logic circuit1506 (which are collectively referred to as “peripheral circuit” on the substrate. Acounter substrate1507 is put together with such an active matrix substrate. A liquid crystal layer (not shown) is sandwiched between the active matrix substrate and thecounter substrate1507.
• In the configuration shown inFIG. 15, all side surfaces of the active matrix circuit and counter substrate are preferably aligned except one particular side. This makes it possible to increase the number of parts obtained from a large substrate efficiently. At one side as described above, a part of the counter substrate is removed to expose a part of the active matrix substrate where an FPC (flexible printed circuit)1508 is mounted. An IC chip (a semiconductor circuit constituted by MOSFETs formed on single crystal silicon) may be loaded in this region as needed.
• Since a TFT whose active region is CGS has a very high operating speed, it is possible to form a signal processing circuit for driving at a high frequency in the range from several hundred MHz to several GHz integrally with a pixel matrix circuit on the same substrate. That is, the liquid crystal panel shown inFIG. 15 is specific form of a system on panel.
• The present invention may be applied not only to liquid crystal display devices integrated with driving circuits but also to the so-called external type display device in which driving circuits are formed on a substrate different from that for the liquid crystal panel.
• While the present embodiment discloses an application of the present invention to a liquid crystal display device, it is possible to configure an active matrix EL (electro-luminescence) display device or the like. It is also possible to form an image sensor having a photoelectric conversion layer or the like on the same substrate.
• [Method for Fabricating CGS and Structure of the Same]
• A description will now be made with reference toFIGS. 8 through 10 on a method for fabricating “continuous grain silicon (CGS)” used for the present invention and a structure of the same.
• [Steps for Fabricating CGS]
• First, an amorphous semiconductor thin film is formed on an insulating substrate using a low pressure CVD process, plasma CVD process or sputtering process.
• Typically, an amorphous silicon film may be used as the amorphous semiconductor thin film. A compound of silicon and germanium expressed by Si_XGe_1-X(O<X<1) may be used as the semiconductor thin film. The thickness of the amorphous semiconductor thin film is in the range from 25 to 100 nm (preferably in the range from 30 to 60 nm).
• It is preferable to reduce impurities such as carbon, oxygen and nitrogen mixed in the film thoroughly because they can hinder subsequent crystallization. Specifically, the concentration of both of carbon and nitrogen is preferably 5×10¹⁸atoms/cm³or less (typically, less than 5×10¹⁷atoms/cm³), and the concentration of oxygen is preferably 1.5×10¹⁹atoms/cm³or less (typically, less than 1×10¹⁸atoms/cm³). By keeping the concentrations within the above-described ranges during the formation of the film, the impurity concentration of finished TFTs can be also kept within the above ranges.
• It is advantageous to add an impurity element (an element selected from the column III which is typically boron or an element selected from the column V which is typically phosphorus) to control the threshold voltage (Vth) of the TFTs during the formation of the film. The dose must be determined in consideration to the threshold voltage Vth which is achieved without the above-described impurity for controlling the threshold voltage Vth.
• Next, a step of crystallizing the amorphous semiconductor thin film is carried out. The techniques disclosed by the inventors in Japanese unexamined patent publication No. H7-130652 is used as the means for crystallization. While either of the means disclosed in the first and second embodiments in the same publication may be used, it is preferable to use the technique disclosed in the second embodiment (detailed in Japanese unexamined patent publication No. H8-78329) for the present invention.
• According to the technique disclosed in Japanese unexamined patent publication No. H8-78329, a mask insulation film is formed first to select regions to be doped with a catalytic element. A solution including the catalytic element for promoting the crystallization of the amorphous semiconductor thin film is applied using a spin coating process to form a layer including the catalytic element.
• The catalytic element used may be one element or a plurality of element selected from among nickel (Ni), cobalt (Co), iron (Fe), palladium (Pd), platinum (Pt), copper (Cu), gold (Au), germanium (Ge) and lead (Pb). It is especially preferred to use nickel which is excellent in lattice matching with silicon.
• The above-described step of adding a catalytic element is not limited to a spin coating process, and an ion implantation process or plasma doping process utilizing a mask may be used. This technique will be effective in forming fine circuits because it facilitates reduction of the area occupied by the doped regions and control over the growing distance of laterally grown regions.
• When the step of adding a catalytic element is completed, hydrogen purging is carried out for about two hours at 500° C. and, thereafter, a heating process is carried out at a temperature in the range from 500° C. to 700° C. (typically in the range from 550° C. to 650° C. and preferably at 570° C.) in a hydrogen atmosphere or oxygen atmosphere to crystallize the amorphous semiconductor thin film.
• At this point, the crystallization of the amorphous semiconductor thin film proceeds from nuclei generated in the regions doped with the catalytic element in precedence to other regions to form crystalline regions which are grown substantially in parallel with the surface of the substrate. The inventors refer to such crystalline regions as “laterally grown regions”. A laterally grown region is advantageous in that it has high crystallinity as a whole because individual crystals are concentrated at a relatively high level of alignment with each other.
• When the heating process for crystallization is completed, a heating process is carried out after removing the mask insulation film to eliminating the catalytic element (a process of gettering the catalytic element). This heating process is to introduce a halogen element in the processing atmosphere to utilize an effect of gettering metal elements exhibited by a halogen element.
• In order to utilize the gettering effect of the halogen element sufficiently, the above-described processing temperature is preferably increased above 700° C. The gettering effect may not be demonstrated at a lower temperature because of difficulty in decomposition of halogenides in the processing atmosphere. For this reason, it is preferred that the temperature for the heating process is kept in the range from 800 to 1000° C. (typically at 950° C.) and that the processing time is in the range from 0.1 to 6 hours and typically in the range from 0.5 to 1 hour.
• Typically, a heating process may be performed for 30 minutes at 950° C. in an oxygen atmosphere including hydrogen chloride (HCl) at a concentration in the range from 0.5 to 10% by volume (preferably 3% by volume). An HCl concentration higher than the above-described concentration is not preferable because it results in irregularities having a thickness on the order of the film thickness on the surface of a laterally grown region.
• Referring to the compound including a halogen element, in addition to. HCl gas, it is possible to use one or a plural kinds of compounds selected from among compounds including a halogen element such as HF, NF₃, HBr, Cl₂, ClF₃, BCl₃, F₂and Br₂.
• At this step, a catalytic element in a laterally grown region is gettered by the action of chlorine and escapes as a volatile chloride into the air to be removed. After this step, the concentration of the catalytic element in the laterally grown region is reduced to 5×10¹⁷atoms/cm³or less (typically 2×10¹⁷atoms/cm³or less).
• A laterally grown region thus obtained has a unique crystal structure formed by a collection of bar-shaped or planar bar shaped crystals. The characteristics of the same will be described below.
• [Findings on the Crystal Structure of a Laterally Grown Region]
• A laterally grown region formed with the above-described steps of fabrication has a crystal structure in which a plurality of bar-shaped (or planar bar-shaped) crystals are regularly arranged in a predetermined direction substantially in parallel with each other when viewed microscopically. This can be easily conformed through observation using TEM (transmission type electronic microscopy).
• The inventors have closely observed the grain boundary of a semiconductor thin film obtained according to the above-described method of fabrication using HR-TEM (high resolution transmission type electronic microscopy) (seeFIG. 16). In the context of the present specification, it is defined that the term “grain boundary” means a grain boundary formed at a boundary where different bar-shaped crystals contact each other unless otherwise specified. It is therefore regarded different from a boundary in a macroscopic sense of the word which is formed as a result of, for example, collision between separate laterally grown regions.
• The above-described HR-TEM (high resolution transmission type electronic microscopy) is a technique wherein electron beams are vertically applied to a sample and the arrangement of the atoms and molecules is evaluated based on electrons transmitted therethrough or the interference of elastically scattered electrons. The use of this technique makes it possible to observe the arrangement of crystal lattices as lattice fringes. Thus, the observation of a grain boundary makes it possible to assume the state of atom bonding at the grain boundary.
• A TEM photograph taken by the inventors (FIG. 16) allowed clear observation of a state in which two different crystal grains (bar-shaped crystal grains) contacted with each other at a grain boundary. Further, it has been recognized from the diffraction of electron beams that the two crystal grains were oriented substantially in a {110} direction with a slight offset between the crystal axes thereof.
• On the above-described TEM photograph, a lattice fringe corresponding to a {111} plane was observed in the {110} plane. A lattice fringe corresponding to the {111} plane is a lattice fringe where the {111} plane appears when the crystal grain is cut along the lattice fringe. An easy way to know to what kinds of planes lattice fringes correspond is to know the distance between the lattice fringes.
• The inventors found a very interesting fact as a result of close observation on a TEM photograph taken on a semiconductor thin film obtained using the above-described method of fabrication. Lattice fringes corresponding to the {111} plane were seen on both of two different crystal grains seen on the photograph. It was observed that those lattice fringes extended obviously in parallel with each other.
• Further, lattice fringes of two different crystal grains that were continuous to each other as if they extended across a grain boundary therebetween regardless of a grain boundary existed or not. In other words, it was observed that most of lattice fringes that seemed as if they extended across a grain boundary were in linear continuity in spite of the fact that they were lattice fringes of different crystal grains. This was the same for any grain boundary.
• Such a crystal structure (exactly, the structure of a grain boundary) shows that two different crystal grains are bonded at a very high level of alignment at a grain boundary. That is, it is a configuration in which crystal lattices are arranged continuously at a grain boundary and in which there is a very small possibility of the formation of a trap level attributable to a crystal defect or the like. In other words, crystal lattices are continuous at a grain boundary.
• Referring toFIG. 17, the inventor also analyzed a conventional polycrystalline silicon film (a so-called high temperature polysilicon film) as a reference based on observation utilizing electron beam diffraction and HR-TEM. As a result, crystal fringes in two different crystal grains extended completely differently from each other and substantially no bonding between crystal grains where lattice fringes were continuous at a high level of alignment. That is, it was revealed that lattice fringes are discontinuous in many places at a grain boundary, which results in many crystal defects.
• According to the inventors, a state of atomic bond in which lattice fringes are associated with each other at a high level of alignment as seen in a semiconductor thin film used in a liquid crystal panel of an information processing apparatus of the invention is referred to as “matched bond”, and bonding hands at that time are referred to as “matched bonding hands”. Conversely, a state of atomic bonding in which lattice fringes are not associated with each other at a high level of alignment as frequently seen in conventional polycrystalline silicon films is referred to as “unmatched bond”, and bonding hands at that time are referred to as “unmatched bonding hands (or unpaired bonding hands)”.
• A semiconductor thin film used in the present invention has a very small number of unmatched bonding hands as described above because it exhibits a very high level of alignment at grain boundaries. An observation of a plurality of grain boundaries conducted by the inventors revealed that the ratio of unmatched bonding hands to the entire bonding hands was 10% or less (preferably 5% or less and more preferably 3% or less). That is, 90% or more (preferably 95% or more and more preferably 97% or more) of the bonding hands are matched bonding hands.
• FIG. 18A shows the result of observation based on electron beam diffraction made on a laterally grown region fabricated with the above-described steps.FIG. 18B shows an electron beam diffraction pattern of a conventional polysilicon film (which is referred to as “high temperature polysilicon film) observed for comparison.
• The electron beam diffraction patterns shown inFIGS. 18A and 18B resulted from areas irradiated with electron beams having a diameter of 4.25 μm, and information was collected from sufficiently large areas. The photographs shown here are typical diffraction patterns obtained as a result of an examination on a plurality of arbitrary points.
• FIG. 18A relatively clearly shows diffraction spots (diffraction stigmata) associated with <110> incidence and proves that substantially all crystal grains in the area irradiated with electron beams are aligned in the {110}-direction. In the case of the conventional high temperature polysilicon film shown inFIG. 18B, no regularity was seen on the diffraction spots, and it was revealed that crystal grains orientated in planes other than the {110}-plane were included with irregularity.
• Thus, the semiconductor thin film used in the present invention is characterized in that it exhibits an electron beam diffraction pattern having regularity unique to {110}-orientation in spite of the fact that it is a semiconductor thin film having grain boundaries and is clearly distinguished from conventional semiconductor thin films when compared thereto with respect to electron beam diffraction patterns.
• As described above, the semiconductor thin film fabricated with the above-described fabrication steps was a semiconductor thin film having a crystal structure (exactly speaking, a structure of grain boundaries) completely different from those of conventional semiconductor thin films. The inventors have described the results of analysis on a semiconductor thin film used in the present invention in Japanese patent applications No. H9-55633, No. H9-165216 and No. H9-212428.
• Grain boundaries in a semiconductor thin film used in the present invention as described above substantially have no function of a barrier for blocking carrier movement because 90% or more of the same are constituted by a matched bonding hand. That is, a semiconductor thin film used in the present invention may be substantially regarded as having no grain boundary.
• While grain boundaries have acted as barriers to block carrier movement in conventional semiconductor thin films, high carrier mobility can be achieved in a semiconductor thin film used in the present invention because there is substantially no grain boundary as described above. Therefore, a TFT fabricated using a semiconductor thin film according to the invention has excellent electrical characteristics, which will be described later.
• [Findings on TFT Electrical Characteristics]
• Since a semiconductor thin film used in the present invention may be substantially regarded as a single crystal (no grain boundary substantially exists), a TFT utilizing the same as the active layer has electrical characteristics comparative to those of a MOSFET utilizing single crystal silicon. The following data was obtained from TFTs prototyped by the inventors.
• (1) Referring to subthreshold coefficients to serve as indices of the switching performance of TFTs (quickness in switching between on/off operations), both of an n-channel type TFT and a p-channel type TFT had a small coefficient in the range from 60 to 100 mV/decade (typically in the range from 60 to 85 mV/decade).
• (2) Referring to field effect mobility (μ_FE) to serve as an index of the operation speed of TFTs, the n-channel type TFT and p-channel TFT exhibited great values in the range from 200 to 650 cm²/V_S(typically in the range from 250 to 300 cm²/V_S) and in the range from 100 to 300 cm²/V_S(typically in the range from 150 to 200 cm²/V_S), respectively.
• (3) Referring to threshold voltages (Vth) to serve as indices of the driving voltage of TFTs, the n-channel type TFT and p-channel type TFT had small values in the range from −0.5 to 1.5 V and in the range from −1.5 to 0.5 V, respectively.
• As described above, it was confirmed that quite excellent switching characteristics and high speed operation characteristics can be achieved.
• During the formation of CGS, the above-described annealing step at a temperature (in the range from 700 to 1100° C.) equal to or higher than the crystallization temperature plays an important roll in reducing defects in a crystal grain, which will be described below.
• FIG. 19A is a TEM photograph at a magnification of 250,000 showing a crystalline silicon film at a point in time at until when steps up to the above-described crystallization step have been completed. A defect that appears zigzag can be seen in the crystal grain (the black and white regions appear as a result of a difference in contrast) as indicated by the arrow.
• While such a defect is primarily a stacking fault which is an error in the order of atoms stacked on a silicon crystal lattice plane, it may be dislocation or the like. It seems thatFIG. 19A shows a stacking defect in which a defective plane extends in parallel with the {111}-plane. This can be recognized from the fact that the zigzag defect is bent at an angle of about 70° C.
• Referring now toFIG. 19B, substantially no defect attributable to a stacking fault, dislocation or the like is found in a crystal grain of a crystalline silicon film used in the present invention viewed at the same magnification, and it can be recognized that there is very high crystallinity. This holds true throughout the film surface. Although it is currently difficult to eliminate defects completely, they can be reduced to a degree that can be substantially regarded zero.
• That is, a crystalline silicon film used in a liquid crystal panel of an information processing apparatus may be regarded monocrystalline or substantially monocrystalline because defects in the crystal grains are reduced to a substantially negligible degree and the grain boundaries can not act as barriers against carrier movement thanking to high continuity between them.
• Although both of the crystalline silicon films shown in the photographs inFIGS. 19A and 19B have substantially the same level of continuity at their grain boundaries, there is a big difference between them with respect to the number of defects in the crystal grains. Such a difference in the number of defects is the major reason for the fact that the crystalline silicon film shown inFIG. 19B has electrical characteristics much higher than those of the crystalline silicon film shown inFIG. 19A.
• It is apparent from above that the process of gettering a catalytic element is an indispensable step in the fabrication of CGS. The inventors have contemplated a model as described below for phenomena caused by this step.
• First, in the state shown inFIG. 19A, the catalytic element (which is typically nickel) has been segregated at the defect (which is primarily a stacking fault) in the crystal grain. Specifically, it is considered that there are many bonds such as Si—Ni—Si.
• However, the process of gettering the catalytic element removes Ni present in the defect to break Si—Ni bonds. As a result, the redundant bonding hands of silicon immediately form Si—Si bonds to be stabilized. This eliminates the defect.
• While it is of course known that thermal annealing at a high temperature eliminates defects in a crystalline silicon film, it can be assumed that the breakage of bonding with nickel produces a great number of uncombined hands to allow smooth recombination of silicon.
• Further, the inventors have an idea of a model in which a heating process at a temperature (in the range from 700 to 1100° C.) equal to or higher than the crystallization temperature secures a crystalline silicon film to the base thereof to increase the degree of adhesion therebetween, thereby eliminating defects.
• A crystalline silicon film (FIG. 19B) thus obtained is characterized in that it has defects in the crystal grains in a quantity much smaller than that of a crystalline silicon film which has been simply crystallized. (FIG. 19A). The difference in the number of defects takes the form of a difference in spin density identified by an analysis on electron spin resonance (ESR).
• Presently, the spin density of a crystalline silicon film used in the present invention is at least 1×10¹⁸pcs./cm³or less (typically 5×10¹⁷pcs./cm³or less).
• A crystalline silicon film used in the present invention having the above-described crystal structure and characteristics is referred to as “continuous grain silicon (CGS)”.
• A second embodiment of the present invention will now be described.
• The present embodiment refers to an example in which a display device (head mount display) is used to provide a virtual display of a 3D (three-dimensional) image. The present embodiment will be described referring again toFIG. 5. There is no particular limitation liquid crystal panels of the display device as long as they are liquid crystal panels-which performs line sequential scan of pixel TFTs and which use A.C. drives (alternating drives) at a frequency band (in the range from about 30 Hz to about 180 Hz) invisible to human eyes.
• As the 3D (three dimensional) images, there is provided two pieces of different image information, i.e., animage signal502R for the right eye and animage signal502L for the left eye. The present embodiment employs a configuration in which an external device (controller, storage device or the like) forms the two different image signals and inputs them to aliquid crystal panel414 for the right eye and aliquid crystal panel413 for the left eye to simplify the configuration of the display device.
• When the twoimage signals502R and502L are obtained using two image pick-up devices to pick up a three-dimensional image, image information thus obtained may be directly used.
• 3D (three-dimensional) images can be obtained by respectively inputting the above-described two different image signals502R and502L toliquid crystal controllers501R and501L which form signals to be input to the liquid crystal panels for the right and left eyes, respectively. Specifically, theliquid crystal controllers501R and501L converts the image information signals502R and502L into signals that cause images displayed on the liquid crystal panels to be recognized by human eyes as 3D (three-dimensional) images. Obviously, the order of the processes on the signals in themain body103 of the display device may be changed appropriately depending on the circuit design.
• In addition, a configuration is preferred in which a select switch or the like is provided in the display devicemain body103 to make it possible also to display 2D (two-dimensional) images.
• The liquid crystal panels of the display device used in the information processing apparatus of the present embodiment can be also provided according to the method of fabrication described in the first embodiment.
• A third embodiment of the present invention will now be described.
• The present embodiment describes to another mode of carrying out the invention with reference toFIG. 6.FIG. 6 is a schematic view of an information processing apparatus of the present embodiment.
• As shown inFIG. 6, the information processing apparatus of the present embodiment comprises an input terminal601, a controller (a computer or the like)602, atransmitter603, a display device (HMD)605 and the like.607 designates a virtual display screen which is actually observed by a user600. Thecontroller602 is electrically connected to thetransmitter603 which outputs image signals, information signals and the like from thecontroller602 through anantenna604 as electric waves. The output electric waves are received by anantenna606 of thedisplay device605 to supply the image signals and information signals to thedisplay device605. Although not shown, thedisplay device605 incorporates a receiver. The internal structure of the display device is the same as that of the first embodiment.
• In the information processing apparatus of the present embodiment, complicated wiring can be eliminated because thedisplay device605 and controller transmit and receive information on a cordless basis.
• Liquid crystal panels of the display device used in the information processing apparatus of the present embodiment may be also provided according to the method of fabrication described in the first embodiment.
• A fourth embodiment of the present invention will now be described.
• The present embodiment describes to still another mode of carrying out the invention with reference toFIG. 7.FIG. 7 is a schematic view of an information processing apparatus of the present embodiment.
• As shown inFIG. 7, the information processing apparatus of the present embodiment comprises an input terminal701, a controller (a computer or the like)702, aCCD camera703, atransmitter704, a display device (HMD)706 and the like. While only one CCD camera is illustrated according to the present embodiment, a plurality of CCD cameras may be provided. The present invention is not limited to theCCD camera703, and any image pick-up device may be employed.
• 708 designates a virtual display screen which is actually observed by a user700. Thecontroller702 is electrically connected to thetransmitter704 which outputs image signals, information signals and the like from thecontroller702 through anantenna705 as electric waves. The output electric waves are received by anantenna707 of the display device706 to supply the image signals and information signals to the display device706. Although not shown, the display device706 incorporates a receiver. The internal structure of the display device is the same as that of the first embodiment.
• TheCCD camera703 picks up images around a keyboard and a work desk and converts them into electric signals to supply information to thecontroller702. Thecontroller702 performs image processing on the information from theCCD camera703 and supplies the information along with other information to the display device706 through thetransmitter704. In the present embodiment, the display device706 and controller transmit and receive information on a cordless basis as in the third embodiment.
• Reference is now made toFIG. 8.FIG. 8 shows avirtual display screen801. Thevirtual display screen801 is capable of displaying a plurality of pieces of information at a time. InFIG. 8, a plurality ofwindows802 through804 are displayed. Thewindow802 displays a word processor screen; thewindow803 displays an image of a keyboard picked up by theCCD camera703; and thewindow804 displays an image of a reference article or the like picked up by theCCD camera703.
• The image of a keyboard displayed in thewindow803 may be an image picked up by theCCD camera703 displayed without image processing thereon. Some kind of image processing may be performed to supply a clear image. Instead of information from the CCD camera, information may be provided using the keyboard as a touch sensor.
• The image of a keyboard displayed in thewindow803 may be drawn using computer graphics. In this case, image processing may be performed on an image of a hand of the user picked up by theCCD camera703 to draw the user's hand on a computer graphics basis.
• The image of a reference article displayed in thewindow804 may be the image picked up by theCCD camera703 displayed without image processing thereon. Some kind of image processing may be performed to supply a clear image. For example, when the user needs to recognize characters only, image processing may be performed on the image picked up by theCCD camera703 to display only characters in thewindow804.
• Liquid crystal panels of the display device used in the information processing apparatus of the present embodiment may be also provided according to the method of fabrication described in the first embodiment.
• A fifth embodiment of the present invention will now be described.
• The present embodiment describes still another mode of carrying out the invention with reference toFIG. 9.FIG. 9 is a schematic view of an information processing apparatus of the present embodiment.
• As shown inFIG. 9, the information processing apparatus of the present embodiment comprises an input terminal901, a controller (a computer or the like)902, aCCD camera903, atransmitter904, a display device (HMD)906, amicrophone908 and the like. While only one CCD camera is illustrated according to the present embodiment, a plurality of CCD cameras may be provided.
• In the present embodiment, the voice of a user900 is picked up by themicrophone908 and the same information is supplied to the display906. The display device906 supplies the information from a transmitter incorporated therein to thetransmitter904 connected to thecontroller902. Thecontroller902 recognizes the voice of the user and performs various processes thereon.
• Liquid crystal panels of the display device used in the information processing apparatus of the present embodiment may be also provided according to the method of fabrication described in the first embodiment.
• A sixth embodiment of the present invention will now be described.
• The present embodiment describes still another mode of carrying out the invention with reference toFIG. 10.FIG. 10 is a schematic view of an information processing apparatus of the present embodiment.
• As shown inFIG. 10, the information processing apparatus of the present embodiment comprises aninput terminal1001, a controller (a computer or the like)1002, aCCD camera1003, atransmitter1004, a display device (HMD)1006, areceiver1007, amicrophone1009 and the like. While only one CCD camera is illustrated according to the present embodiment, a plurality of CCD cameras may be provided.
• The information processing apparatus of the present embodiment is characterized in that the receiver incorporated in the display device of the information processing apparatus described in the fifth embodiment is externally provided. This allows some reduction of the weight of the display device.
• Liquid crystal panels of the display device used in the information processing apparatus of the present embodiment may be also provided according to the method of fabrication described in the first embodiment.
• A seventh embodiment of the present invention will now be described.
• The present embodiment describes still another mode of carrying out the invention with reference toFIG. 11. InFIG. 11, there is shown a schematic view of the information processing apparatus according to the present embodiment.
• As shown inFIG. 11, the information processing apparatus of the present embodiment comprises a display device (HMD)1101, a receiver (not shown), a transmitter (not shown), anantenna1102, amicrophone1103 and the like.1104 designates a virtual display screen which is actually observed by a user. While the transmitter and receiver of the present embodiment are incorporated in thedisplay device1101, they may be provided externally as in the sixth embodiment.
• The information processing apparatus of the present embodiment has a function of displaying a virtual display screen in an overlapping relationship with the surrounding scene as described in the first embodiment. This allows a user to go out with the information processing apparatus of the present embodiment worn by him or her. If the view of the environment is shut out, the user can concentrate on the virtual display screen. This also allows the user to relax because the user is isolated from the environment surrounding him or her. Needless to say, a switching device is provided to allow the user to switch such modes. The display device may have a configuration including a function of automatic switching depending on image signals input thereto.
• Reference is now made toFIG. 12.FIG. 12 shows avirtual display screen1104 according to the present embodiment.FIG. 12 shows a situation in which a user actually observes the information processing apparatus of the present invention in use while the user is walking.
• When a traffic light turns red as the user approaches it, information from abeacon1203 installed on the street is received by the receiver of the display device, which causes awindow1202 showing information such as “red signal!” to appear on thevirtual display screen1104 on the display device. This allows even a user with a weak sight to notice the red signal quickly.
• It is also possible to alert a user with low hearing ability by displaying a window showing information indicating that a train is approaching in thevirtual display screen1104 based on information from a beacon installed at a train station.
• Awindow1201 showing date and time may be always shown.
• Liquid crystal panels of the display device used in the information processing apparatus of the present embodiment may be also provided according to the method of fabrication described in the first embodiment.
• An eighth embodiment of the present invention will now be described.
• While the above-described first through seventh embodiments have referred to the use of liquid crystal panels as display devices used in information processing apparatuses according to the invention, an active matrix type EL (electro-luminescence) display device or the like may alternatively be used. Furthermore, an image sensor or the like having a photoelectric conversion layer may be formed on the same substrate.
• A ninth embodiment of the present invention will now be described.
• In the display devices of the first through seventh embodiments, the writing period must be short to achieve high resolution. The present embodiment refers to an example in which antiferroelectric liquid crystal having substantially no threshold is used as the material of the liquid crystal panels used in each of the embodiments when image information with relatively high image quality is used.
• A liquid crystal material used in a conventional LCD suffers from a low speed of response to the application of a voltage (in the range from several tens ms to several hundred ms) and, even if a driving circuit is formed, for example, by TFTs operable at a high frequency band using crystalline silicon (CGS), the liquid crystal material can not respond to such a high speed operation.
• In the present embodiment, however, crystalline silicon (CGS) is used; TFTs operable at a high frequency band are used as switching elements for liquid crystal panels; and antiferroelectric liquid crystal is used which has a high speed of response to the application of a voltage and which has substantially no threshold. This makes it possible to provide a display device having high definition and high resolution free from flickers.
• This is advantageous also in a case wherein ferroelectric liquid crystal is used as the material of liquid crystal panels and a special alignment layer is used to eliminate a memory effect of the ferroelectric liquid crystal.
• A tenth embodiment of the present invention will now be described.
• The present embodiment refers to an example of a configuration wherein red (R), green (G) and blue (B) light emitting diodes are used as back lights and incorporated in the main body of a display device. Referring to color display in this case, for example, each of the R, G and B light emitting diodes is blinked such that they are repeated in a sequence of R, G, B, R, G, B, R, in a time series at a frequency which is three times the writing period for one screen (frame frequency), which causes human eyes to recognize a color image. In the present embodiment, one screen was written at 60 Hz and each of the R, G and B light emitting diodes was blinked such that they were repeated in a sequence of R, G, B, R, G, B, R, in a time series at a frequency of 180 Hz which was three times the same. There is no special limitation on the writing period for one screen (referred to as “frame frequency”) as long as it is 45 Hz or more and preferably 60 Hz or more. In this case, since no, color filter is needed, bright display can be achieved.
• The back lights may be configured using light emitting elements such as EL elements instead of light emitting diodes.
• An eleventh embodiment of the present invention will now be described.
• While the first embodiment has referred to the fabrication of a liquid crystal panel by using Ni as a catalytic element, according to the present embodiment, a liquid crystal panel is fabricated using Ge (germanium) as a catalytic element.
• A liquid crystal panel fabricated according to the present embodiment may obviously be used in the above-described second through tenth embodiments.
• An information processing apparatus according to the present invention employs a head mount display (HMD) as means for providing a user with an image and can display a plurality of pieces of information at a time on a virtual display screen provided by the head mount display. This makes it possible to reduce the size of an information processing apparatus while providing images having high definition and high resolution.
• In addition, while it has been difficult to read small characters on a conventional HMD because of its low resolution, a liquid crystal panel used in an information processing apparatus according to the present invention allows accurate information processing operations because it allows even small characters on it to be clearly recognized. That is, the HMD disclosed in this specification is optimum as a display device of an information processing apparatus.

Claims (36)

1-18. (canceled)

19. An information processing device comprising:

an image pick-up device which picks up an image of a hand of a user;

a controller connected to the image pick-up device; and

a display device having a flat panel display mounted on a head of the user,

wherein the image pick-up device converts at least the image of the hand of the user into an electrical signal and supplies the electrical signal to the controller,

wherein the controller transmits the electrical signal in the form of an electric wave to the flat panel display.

20. The information processing device according toclaim 19, wherein the flat panel display comprises a TFT including a channel formation region.

21. The information processing device according toclaim 20, wherein 90% or more of crystal lattices at grain boundaries of the channel formation region have continuity.

22. The information processing device according toclaim 19, wherein the flat panel display comprises a liquid crystal display device including a liquid crystal material.

23. The information processing device according toclaim 19, wherein the image pick-up device is a CCD camera.

24. An information processing device comprising:

an input operation device;

an image pick-up device which picks up an image of a hand of a user;

a controller connected to the input operation device and the image pick-up device; and

a display device having a flat panel display mounted on a head of the user,

wherein the image pick-up device converts at least the image of the hand of the user into an electrical signal and supplies the electrical signal to the controller,

wherein the controller transmits the electrical signal to the flat panel display.

25. The information processing device according toclaim 24, wherein the flat panel display comprises a TFT including a channel formation region.

26. The information processing device according toclaim 25, wherein 90% or more of crystal lattices at grain boundaries of the channel formation region have continuity.

27. The information processing device according toclaim 24, wherein the flat panel display comprises a liquid crystal display device including a liquid crystal material.

28. The information processing device according toclaim 24, wherein the image pick-up device is a CCD camera.

29. The information processing device according toclaim 24, wherein the controller transmits the electrical signals in the form of an electric wave to the flat panel display.

30. An information processing device comprising:

an input operation device;

an image pick-up device which picks up an image of a hand of a user;

a controller connected to the input operation device and the image pick-up device; and

a display device having a flat panel display mounted on a head of the user,

wherein the image pick-up device converts at least the image of the hand of the user into an electrical signal and supplies the electrical signal to the controller,

wherein the controller transmits the electrical signal to the flat panel display, and

wherein image processing is performed on the image of the hand of the user to draw the hand on the flat panel display on a computer graphics basis.

31. The information processing device according toclaim 30, wherein the flat panel display comprises a TFT including a channel formation region.

32. The information processing device according toclaim 31, wherein 90% or more of crystal lattices at grain boundaries of the channel formation region have continuity.

33. The information processing device according toclaim 30, wherein the flat panel display comprises a liquid crystal display device including a liquid crystal material.

34. The information processing device according toclaim 30, wherein the image pick-up device is a CCD camera.

35. The information processing device according toclaim 30, wherein the controller transmits the electrical signals in the form of an electric wave to the flat panel display.

36. An information processing device comprising:

an image pick-up device which picks up an image of a hand of a user;

a controller connected to the image pick-up device; and

a display device having a flat panel display mounted on a head of the user,

wherein the image pick-up device converts at least the image of the hand of the user into an electrical signal and supplies the electrical signal to the controller,

wherein the controller transmits the electrical signal to the flat panel display, and

wherein the flat panel display displays a plurality of pieces of information including the image of the hand of the user at a time.

37. The information processing device according toclaim 36, wherein the flat panel display comprises a TFT including a channel formation region.

38. The information processing device according toclaim 37, wherein90% or more of crystal lattices at grain boundaries of the channel formation region have continuity.

39. The information processing device according toclaim 36, wherein the flat panel display comprises a liquid crystal display device including a liquid crystal material.

40. The information processing device according toclaim 36, wherein the image pick-up device is a CCD camera.

41. The information processing device according toclaim 36, wherein the controller transmits the electrical signals in the form of an electric wave to the flat panel display.

42. An information processing device comprising:

an input operation device;

an image pick-up device which picks up an image of a hand of a user;

a controller connected to the input operation device and the image pick-up device; and

a display device having a flat panel display mounted on a head of the user,

wherein the image pick-up device converts at least images of the input operation device and the hand of the user into electrical signals and supplies the electrical signals to the controller,

wherein the controller transmits the electrical signals to the flat panel display, and

wherein the flat panel display displays a plurality of pieces of information including images of the input operation device and the hand of the user at a time.

43. The information processing device according toclaim 42, wherein the flat panel display comprises a TFT including a channel formation region.

44. The information processing device according toclaim 43, wherein 90% or more of crystal lattices at grain boundaries of the channel formation region have continuity.

45. The information processing device according toclaim 42, wherein the flat panel display comprises a liquid crystal display device including a liquid crystal material.

46. The information processing device according toclaim 42, wherein the image pick-up device is a CCD camera.

47. The information processing device according toclaim 42, wherein the controller transmits the electrical signals in the form of an electric wave to the flat panel display.

48. An information processing device comprising:

an input operation device;

an image pick-up device which picks up an image of a hand of a user;

a controller connected to the input operation device and the image pick-up device; and

a display device having a flat panel display mounted on a head of the user,

wherein the image pick-up device converts at least images of the input operation device and the hand of the user into electrical signals and supplies the electrical signals to the controller,

wherein the controller transmits the electrical signals to the flat panel display, and

wherein the flat panel display displays a plurality of pieces of information including images of the input operation device and the hand of the user at a time, and

wherein image processing is performed on the images of the hand of the user and the input operation device to draw the hand and the input operation device on the flat panel display on a computer graphics basis.

49. The information processing device according toclaim 48, wherein the flat panel display comprises a TFT including a channel formation region.

50. The information processing device according toclaim 49, wherein 90% or more of crystal lattices at grain boundaries of the channel formation region have continuity.

51. The information processing device according toclaim 48, wherein the flat panel display comprises a liquid crystal display device including a liquid crystal material.

52. The information processing device according toclaim 48, wherein the image pick-up device is a CCD camera.

53. The information processing device according toclaim 48, wherein the controller transmits the electrical signals in the form of an electric wave to the flat panel display.

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