US20080310098A1 - Circuit board - Google Patents

Abstract

A circuit board is used in common for the first electronic apparatus as the first configuration and for the second electronic apparatus as the second configuration, and the circuit board includes an area which is used in common for installing the first electronic device in installing the circuit board into the first electronic apparatus, and for installing the second electronic device in installing the circuit board into the second electronic apparatus, wherein the first electronic device is used only for the first electronic apparatus, and the second electronic device is used only for the second electronic apparatus.

Description

• This application claims the right of priority under 35 U.S.C. § 119 based on Japanese Patent Application No. 2004-145504 filed on May 14, 2004, which is hereby incorporated by reference herein in its entirety as if fully set forth herein.
BACKGROUND OF THE INVENTION
• The present invention relates generally to a circuit board, a mounting structure, a mounting method, and an electronic apparatus, and more particularly to a circuit board that is used in common for domestic (i.e., Japanese) market and for overseas market. The present invention is suitable for a motherboard (main board) that is installed in, for example, notebook type computers, personal digital assistants (PDA), handy game instruments, handy electronic apparatuses such as drive units, space saving type electronic apparatuses such as desktop computers or word processors of display integrated type or slim type.
• The demand for electronic apparatuses such as personal computers is now growing. Particularly, handy data processing apparatuses such as notebook type personal computers (hereinafter, “note PCs”.) or PDAs are remarkably improving and widespreading, and they are demanded to be smaller and thinner. Furthermore various functions or apparatuses are installed in the handy data processing apparatuses so as to satisfy the demand for their to have higher performance and more various functions.
• However, the demand to be smaller and thinner is basically contrary to the demand to have higher performance and more various functions. The data processing apparatus becomes big in accordance with having more functions. Still more, the data processing apparatus (or electronic devices installed in the data processing apparatus) generally generates more heat in accordance with having higher performance or more functions. The data processing apparatus will become bigger in accordance with increasing the functions because it also needs cooling function. Therefore, to make the handy data processing apparatus be small, thin, lightweight, high performance, and various functions, the decision of installing the higher necessary performances and functions and not installing the lower necessary performances and functions in the data processing apparatus is needed.
• The necessity of the performances and functions often depends on the consumer targeted. The consumer targeted can be classified, for example, by consumer's age or market destination (domestic or overseas such as to the U.S.A. or to Europe). Therefore, the functions to be installed are differently selected in accordance with grade or market destination in the same series of the data processing apparatuses.
• In such case for example, a motherboard optimized only for Japanese domestic market is used for a note PC for Japanese domestic market, and a motherboard optimized only for overseas market is used for a note PC for overseas market.
• However, many kinds of motherboards should be manufactured for one series of the data processing apparatus in the exclusive motherboards are respectively used for every grade or destination. Thus, many kinds of production molds or production lines of the motherboards should be prepared and it results increase of the production cost. Many kinds of motherboards confuse the assembling process, and it results decrease of assembling performance.
BRIEF SUMMARY OF THE INVENTION
• Accordingly, it is an exemplary object to provide a novel and useful circuit board, a mounting structure, and an electronic apparatus having the same. Concretely, it is an exemplary object to provide a circuit board that can have performances or functions for many grade or destinations of electronic apparatuses and can be used in common for many grades or destinations, and can decrease the production cost and increase the assembling performance of the electronic apparatuses.
• To achieve above-mentioned objects, a circuit board of one aspect according to the present invention is used in common for the first electronic apparatus as the first configuration and for the second electronic apparatus as the second configuration. The circuit board includes an area which is used in common for installing the first electronic device in installing the circuit board into the first electronic apparatus, and for installing the second electronic device in installing the circuit board into the second electronic apparatus, wherein the first electronic device is particularly used for the first electronic apparatus, and the second electronic device is particularly used for the second electronic apparatus.
• Here, the electronic apparatus is, for example, a note PC. And a desktop type personal computer or handy data processing apparatus and the like is applicable to the electronic apparatus. For example, the first configuration and the second configuration means respectively for domestic marker and for overseas market or two different grades of the electronic apparatus. That is, the first electronic apparatus and the second electronic apparatus are the same series but different specifications (configurations). The first electronic device that is particularly used for the first electronic apparatus is, for example, a floppy disk drive unit, and the second electronic device that is particularly used for the second electronic apparatus is, for example, high performance VGA (Video Graphic Array) device which is higher resolution (higher performance) than a standard VGA device. For example, the standard VGA device can display in a resolution of at least 640×480 dots, and the high performance VGA device can display in a resolution of at least 1280×1024 dots.
• As the circuit board can be used in common for domestic market (the first configuration) and for overseas market (the second configuration), many kinds of the circuit board do not have to be produced for one series of the electronic apparatus (for example, note PC). Therefore, it can decrease the production cost and increase the assembling performance. The floppy disk drive unit (the first electronic device) is installed and the high performance VGA device (the second electronic device) is not installed in the electronic apparatus for Japanese domestic market. While, the high performance VGA device is installed and the floppy disk drive unit is not installed in the electronic apparatus for overseas market. A specific area is used in common for installing both devices. In accordance with the destination, the floppy disk drive unit or the high performance VGA device is selectively installed on the specific area. Therefore, the space in the electronic apparatus will be used more effectively, and the electronic apparatus will become smaller and thinner. The specific area is substantially rectangular shape on the circuit board and the size of the area is preferably 96 mm×126 mm or larger. Then, the floppy disk drive unit can be located in the area easily, and influence to other devices on the circuit board can be minimized.
• The third electronic device may be installed on the circuit board both in the first configuration and the second configuration, and the second electronic device may be used instead of the third electronic device alternatively. The third electronic device means, for example, the standard VGA device that is installed in the electronic apparatus for both domestic market and overseas market. The high performance VGA device is used instead of the standard VGA device in the electronic apparatus for overseas market so that it can display with high resolution to satisfy foreign consumer's demand.
• The circuit board may be a single board on which a processing circuit that processes a main control of the first electronic apparatus or the second electronic apparatus is installed. The single board may be a motherboard. The processing circuit may be a CPU. If the circuit board is the motherboard on which the CPU is installed, the space in the electronic apparatus will be used more effectively and the electronic apparatus will become smaller and thinner.
• The first electronic device may include a drive unit for portable storage media and the second electronic device may include a display circuit. For example, the floppy disk drive unit can be used as the drive unit for portable storage media and the high performance VGA device can be used as the display device. In this case, the floppy disk drive unit or the high performance VGA device can be selectively installed on the circuit board in accordance with the configuration (destination) of the electronic apparatus. Still, in the specific area on the circuit board in the electronic apparatus of the second configuration, at least a device to connect an external memory, a device to connect a IEEE1394 connector, a device to connect a video connector, a device to connect a USB (Universal Serial Bus) connector, a device for Bluetooth, and a connector to connect a cooler to cool the high performance VGA device may be installed with the high performance VGA device. Here, the device to connect the external memory means a drive unit that has a slot to insert the external memory such as SD (Secure Digital) memory, memory stick, and the like. The device to connect the IEEE1394 connector means, for example, a connection port based on IEEE1394 standard, and it can be connected with the digital video camera, and the like. The device to connect the video connector means, for example, a S-Video connection port, and it can be connected with the video unit that has the S-Video connector. The device to connect the USB connector means USB connection port, and it can be connected with various external apparatus that is based on the USB standard. A device for Bluetooth means, for example, a wireless communication device to transmit or receive the wireless data that is based on the Bluetooth standard. These devices are sometimes necessary for the electronic apparatus of the second configuration (for overseas market) and not necessary for that of the first configuration (for domestic market). Therefore, by arranging these devices in the specific area unitedly, there will be no devices in the specific area on the circuit board in the electronic apparatus of the first configuration. Thus, the specific area can be used effectively for other devices or functions.
• A cooler to cool the second electronic device may be installed on the circuit board. The high performance VGA device used as the second electronic device generates a lot of heat. However, installing the cooler can minimize a bad influence such as thermal runaway.
• The cooler may be installed in the specific area. The first electronic device is not installed in the second configuration, and the cooler can be easily arranged in the specific area. The size, especially the thickness of the electronic apparatus will merely increase.
• The cooler may be a heat sink unit that includes a heat receiving plate that receives heat from the second electronic device by contacting the second electronic device, a heat conductor that conducts heat from the heat receiving plate to a radiation plate, and a cooling fan that cools the radiation plate by blowing. Thus, the cooler can cool the second electronic device effectively.
• The heat sink unit may have a ventilator that exhausts air from the cooling fan, and the ventilator may be located near a device to connect an external memory that is installed on the circuit board. As the device to connect the external memory merely generates heat, the cooling efficiency does not decrease when the ventilator is located near or on the device. It is not difficult to design the height (i.e., the size along the thickness of the electronic apparatus) of the device to connect the external memory and of the ventilator be small. Therefore, it does not increase the thickness of the electronic apparatus.
• An extension connector part may be installed on the circuit board. Here, the extension connector may connect an extension unit that is removably attachable to the first electronic apparatus and the second electronic apparatus. As the extension unit or the external apparatus can be attachable to the electronic apparatus via the extension connector part, the expansivity of the electronic apparatus will be improved.
• The extension connector part may be installed substantially adjacent to both the install position of the second electronic device on the circuit board and the install position of the third electronic device on the circuit board. The further the extension connector part to connect the extension unit is from the VGA device, the longer the lead cable or the lead pattern between them is, and the bigger the influence of signal noise is. Therefore, the noise signal will be overlapped on the image signal transmitted by the lead cable or the lead pattern, and the VGA device cannot put out the performance sufficiently. Thus, the extension connector part is preferable to be near the VGA device. By locating the install position of the extension connector part substantially adjacent to the install position of the VGA device (the second electronic device or the third electronic device), the VGA device will put out its performance sufficiently.
• The second electronic device may be installed at a position in the area so that the distance between the extension connector part and the second electronic device is substantially the same as the distance between the extension connector part and the third electronic device. By equalizing the distance from the extension connector part to two VGA devices (the second and the third electronic devices), transmission quality of the image signal will not be different in the first configuration and in the second configuration.
• The extension connector part may be installed in an overlapped area that is used both when the circuit board is installed in the electronic apparatus in the first direction and when the circuit board is installed in the electronic apparatus in the second direction.
• Here, the first direction is, for example, the width direction of the electronic apparatus in using state (hereinafter, “width direction”.). The second direction is, for example, the depth direction of the electronic apparatus in using state (hereinafter, “depth direction”.). On reason for designing, there are two types of the motherboard installed in the electronic apparatus. One is a motherboard of width direction layout, and the other is that of depth direction layout. While, extension unit is used in common in a lot of electronic apparatuses in spite of the motherboard's layout direction. So, the position and the shape of the extension connector part are preferably the same in every kind of the electronic apparatus. By locating the extension connector part in the overlapped area, same extension connector part can be used both in the electronic apparatus having the motherboard of width direction layout and in the electronic apparatus having the motherboard of depth direction layout.
• An install position of the extension connector part may be within a specific distance from a back face of the electronic apparatus when the circuit board is installed in the electronic apparatus, and within a specific distance from a centerline of width of the electronic apparatus. For example, the install position of the extension connector part may be within 30 mm from the back face of the electronic apparatus, and within 30 mm from the centerline of width of the electronic apparatus when seen from a front face. Thus, the extension unit can be connected with the electronic apparatus at its back face easily. The arrangement of the circuit board in the electronic apparatus will become free.
• The extension unit may be a connection apparatus that has a plurality of connectors for peripheral apparatuses. For example, the connection apparatus may be a port replicator. By connecting the port replicator with the electronic apparatus, more external apparatuses can be connected with the electronic apparatus via the port replicator and the expansivity of the electronic apparatus improves.
• The connection apparatus that has a width substantially the same as the width of the electronic apparatus may be removably attachable to the back face of the electronic apparatus. The connection apparatus may have a projection part on which a connector being connectable to the extension connector part is located. As the width of the connection apparatus is substantially the same as the width of the electronic apparatus, feeling of use and portability of the electronic apparatus with the connection apparatus attached thereto will be good. The projection can make the size or the weight of the connection apparatus be reduced.
• An electronic apparatus of another aspect according to the present invention includes the above mentioned circuit board installed therein. Thus, in addition to the above mentioned effects, it can make the electronic apparatus be small, thin, lightweight, high performance, and various functions. If the circuit board is the motherboard, it will not be necessary to prepare the several different motherboards for every grade or every destination in one series of the electronic apparatus. Therefore, it can decrease the production cost and increase the assembling performance.
• The electronic apparatus may be used in common for the first configuration and for the second configuration, and may have a package being substantially rectangular parallelepiped shape. For example, the size of the package is 333 mm×285 mm×38 mm or smaller. It can decrease the production cost and increase the assembling performance because the package can be used in common for a plurality of the configurations. The size of 333 mm×285 mm×38 mm or smaller can make the notebook type computer be small.
• The electronic apparatus may be a notebook type computer. Thus, the notebook type computer will be small, thin, lightweight, high performance, and various functions. And it can decrease the production cost and increase the assembling performance of the notebook type computer.
• A circuit board of still another aspect according to the present invention is for an electronic apparatus. The circuit board has a plurality of electronic devices installed on the surface of the circuit board, and is used in common for at least two configurations. An install position of at least two electronic devices on the surface of the circuit board is in a united area. The at least two devices are not installed on the surface of the circuit board in the first configuration of the at least two configurations, and are installed on the surface of the circuit board in the second configuration of the at least two configurations.
• An electronic apparatus of still another aspect according to the present invention includes a circuit board that has a plurality of electronic devices installed on the surface of the circuit board, and is used in common for at least two configurations. An install position of at least two electronic devices on the surface of the circuit board is in a united area. The at least two devices are not installed on the surface of the circuit board in the first configuration of the at least two configurations, and are installed on the surface of the circuit board in the second configuration of the at least two configurations. Here, the electronic apparatus includes at least either the first electronic apparatus or the second electronic apparatus.
• As the circuit board is used in common for the domestic market (the first configuration) and for the overseas market (the second configuration), it is not necessary to produce many kinds of circuit boards for one series of the electronic apparatus. Therefore it can decrease the production cost and increase the assembling performance. If a function is not installed in the electronic apparatus for domestic market and the same function is installed in that for overseas market, a plurality of the electronic devices in relation to the function are not installed on the circuit board for domestic market and are installed on that for overseas market. Arranging these electronic devices in the specific area unitedly can generate an empty area that has no electronic devices on the circuit board for domestic market. Thus, it will be easy to install other functions or other units that is necessary for domestic market but not necessary for overseas market in the empty area on the circuit board. Here, the united specific area means, for example, a rectangular shape area of a specific extent which has no electronic devices on the circuit board.
• Other objects and further features of the present invention will become readily apparent from the following description of the preferred embodiments with reference to accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a perspective view of a notebook type personal computer including 2 motherboard of one embodiment according to the present invention.
• FIG. 2 is a bottom view of the notebook type personal computer shown inFIG. 1.
• FIG. 3 is a whole perspective view of a port replicator used with the notebook type personal computer shown inFIG. 1.
• FIG. 4A is a perspective view seen from front face in the state of connecting the port replicator with the notebook type personal computer shown inFIG. 1.FIG. 4B is a perspective view seen from back face in the state of connecting the port replicator with the notebook type personal computer shown inFIG. 1.
• FIG. 5 is a whole perspective view of the motherboard installed in a main unit of the notebook type personal computer shown inFIG. 1.
• FIG. 6A is a perspective view of top face of a heat sink unit to be installed in the notebook type personal computer shown inFIG. 1.FIG. 6B is a perspective view of bottom face of the heat sink unit to be installed in the notebook type personal computer shown inFIG. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
• [The Explanation of a Notebook Type Personal Computer For Overseas Market]
• Referring now to the accompanied drawings, a description will be now given of a circuit board of one embodiment according to the present invention.FIG. 1 is a perspective view of a notebook type personal computer1 (note PC1) as an electronic apparatus including a motherboard (single board) as one embodiment of a circuit board according to the present invention. Thenote PC1 has adisplay part2 and amain unit4. Thedisplay part2 is rotatably connected with themain unit4 by a hinge, and in can be open and close. Thisnote PC1 is a computer (the second electronic apparatus) for overseas market (the second configuration), and a computer (the first electronic apparatus) for domestic market (the first configuration) in the same series will be explained later.
• Thedisplay part2 is for displaying various information such as movies, pictures, or characters, and uses for example a liquid crystal display unit (LCD) of 15 inches or 17 inches. Thenote PC1 is folded b) rotating thedisplay part2 toward themain unit4 around the hinge when a user does not use thenote PC1. Thedisplay part2 is opened and raised from themain unit4 when the user uses thenote PC1.
• Themain unit4 has most of basic functions of thenote PC1. For example, themain unit4 includes akeyboard6, atouch panel8, and asub display9 on its surface. Thekeyboard6 is an input device by using the keys for the user to input information to thenote PC1. The touch panel is also a kind of input devices, and uses for example an electrostatic touch sensor. A mouse cursor moves in thedisplay part2 in accordance with the movement of the user's finger on thetouch panel8. Thesub display9 indicates a status of thenote PC1 such as a power on/off, a hard disk status, and a battery charge status. For example, thesub display9 uses LEDs or monochrome LCD.
• Themain unit4 further has a power switch (not shown), a PCcard drive unit10, an optical disk drive unit12 (see alsoFIG. 4B), SD card drive unit (a device to connect an external memory)14, aIEEE1394 port16, a S-Video connection port18, and aUSB port20 on its side face. The PCcard drive unit10 is for inserting and connecting the card devices that is based on the PC card standard and have various functions. The opticaldisk drive unit12 is for reading the data from CD-ROM. It can have functions of reading from or writing to CD-R. CD-RW, DVD-ROM, DVD-R, DVD-RW, or DVD-RAM. The SDcard drive unit14 is for inserting and connecting the SD card as an external memory. Themain unit4 can include a compact flash memory drive unit or memory stick drive unit instead of the SDcard drive unit14. TheIEEE1394 port16 is for connecting various apparatuses based on IEEE1394 standard. For example, a digital video camera is connected with theIEEE1394 port16. The S-Video connection port18 is for connecting imaging apparatuses that output S-Video signal. TheUSB port20 is for connecting various apparatuses based on USB standard.
• FIG. 2 is a bottom view of themain unit4 seen from bottom face. As shown inFIG. 2, themain unit4 has anextension connector part22 on its bottom face to connect a port replicator (a connection apparatus)23 as an extension unit (see alsoFIG. 3). Theextension connector part22 is located within 30 mm as a specific distance from aback face1aof thenote PC1. When seen from afront face1bin using state of thenote PC1, theextension connector part22 is located within 30 mm as a specific distance to the left (to the right inFIG. 2) from a centerline of width of thenote PC1. Thus, shown inFIGS. 4A and 4B, theport replicator23 can be attached to or removed from theback face1aof thenote PC1 easily. As theextension connector part22 can be installed on the motherboard both in the depth direction layout and in the width direction layout which will be explained later, the arrangement of the motherboard in themain unit4 becomes free.
• FIG. 3 is a whole perspective view of theport replicator23 as the extension unit. Theport replicator23 includes aconnector23ato be connected electrically with theextension connector part22 on themain unit4, a connectingpart23bto be connected mechanically with theback face1aof themain unit4, and arelease button23cthat is used to release theport replicator23 from themain unit4. Theconnector23ais arranged on aprojection23dpartially projected from amain body23e. The width of themain body23eis approximately the same as the width of thenote PC1. Theport replicator23 is a connection apparatus that can connect various apparatuses with thenote PC1 by expanding the function of thenote PC1. As shown inFIG. 4B, a lot of ports (connectors for peripheral apparatuses) such as aLAN port23j, an analog RGB output port23k, an opticaldigital output port23f, aserial port23g, aparallel port23h, and aUSB port23iare located on the back face of theport replicator23. By connecting external apparatuses with these ports via cables, thenote PC1 can further expand the functions.
• Themain unit4 includes amotherboard24 as a circuit board therein.FIG. 5 is a whole perspective view of themotherboard24. On the one side of themotherboard24, a CPU (a processing circuit)26, a memory as an information storage device (not shown), a standard VGA device (the third electronic device, a display circuit)28, a high performance VGA device (the second electronic device, a display circuit)30, a Bluetooth unit (a device for Bluetooth)32, and a connector for heat sink unit (connector for cooler)34 are installed. And theextension connector part22 for the port replicator is installed on the other side of themotherboard24. A lot of other devices are installed on themotherboard24, and the PCcard drive unit10, abattery36, and the opticaldisk drive unit12 are also arranged on themotherboard24.
• Themotherboard24 is, for example, a rectangular shape. If themotherboard24 is arranged with its long side along the width direction (the first direction) of themain unit4, it is called “width direction layout”. If themotherboard24 is arranged with its long side along the depth direction (the second direction) of themain unit4, it is called “depth direction layout”. There are width directionlayout type motherboard24 and depth directionlayout type motherboard24. An area that is overlapped by width direction layout type motherboard and depth direction layout type motherboard in themain unit4 is called an overlapped area B (the area enclosed by thick line inFIG. 5). Theextension connector part22 is located in the overlapped area B. Thus, theport replicator23 can be used in common for thenote PC1 including the width direction layout type motherboard and for thenote PC1 including the depth direction layout type motherboard because the position of theextension connector part22 does not change.
• Thestandard VGA device28 and the highperformance VGA device30 are both electronic devices for displaying graphics. They has a function of processing the positions or colors in displaying movies pictures, or characters on thedisplay part2. Thestandard VGA device28 is, for example, for displaying the movies etc. on thedisplay part2 with 640×480 dots. The highperformance VGA device30 is, for example, for displaying the movies etc. on thedisplay part2 with 1280×1024 dots and has a resolution higher than the standard VGA device does. TheBluetooth unit32 is a wireless communication device to transmit or receive the wireless data that is based on the Bluetooth standard. Theconnector34 for heat sink unit is a power supply connector that supplies electric power to the heat sink unit (the cooler)38 for the highperformance VGA device30, explained later.
• On themotherboard24, the SDcard drive unit10, theIEEE1394 port16, S-Video connection port18, theUSB port20, the highperformance VGA device30, theBluetooth unit32, theconnector34 for heat sink unit as electronic devices (hereinafter, these seven electronic devices are generically called “the electronic devices for overseas only”) are unitedly installed in the specific area A of approximately rectangular shape shown inFIG. 5 as a hatching part. And above the specific area A, theheat sink unit38 is arranged so as to cover the electronic devices for overseas only.FIG. 6A is a perspective view of top face of theheat sink38 andFIG. 6B is a perspective view of bottom face of theheat sink38. Theheat sink unit38 includes aheat receiving plate38a, a heat pipe (a heat conductor)38b, a heat radiation plate (not shown), a coolingfan38c, and aventilator38d. Theheat receiving plate38areceives the heat from the highperformance VGA device30 by contacting to the top face of the highperformance VGA device30, the heat is conducted by theheat pipe38bto the heat radiation plate located near theventilator38d, and the radiation plate is cooled by blowing of the coolingfan38c. The blowing air is exhausted to out of thenote PC1 through theventilation38d. Theventilation38dis provided on aslot38efor inserting the SD card into the SDcard drive unit14.
• Thisnote PC1 is for overseas market (the second configuration) that needs high performance VGA function and Bluetooth function. Therefore, the highperformance VGA device30 and theBluetooth unit32 are installed on themotherboard24 in thenote PC1. And more, the heat sink unit for cooling the highperformance VGA device30 is also installed in thenote PC1. As shown inFIG. 6B, there are not so many devices near the bottom face of theheat sink unit38, and theheat sink unit38 arranged above themotherboard24 so as to cover the electronic devices for overseas only does not interfere to theBluetooth unit32 or theconnector34 for heat sink unit. Therefore, themain unit4 of thenote PC1 for overseas market can be thin. Theheat sink unit38 is a thin rectangular parallelepiped shape, and the rectangular area projected on themotherboard24 is approximately the same as that of a floppy disk drive unit (a first electronic device, a drive unit for portable storage media)40 explained later. The projected area is in accordance with the area of the specific area A. Concretely, the projected area is not more than the area of the specific area A. Thus, theheat sink unit38 can be arranged in the range of the specific area A. The size of the specific area is preferably 96 mm×126 mm or smaller to arrange theheat sink unit38 or the floppydisk drive unit40 in the range of the specific area A and to secure the install area for other devices on themotherboard24.
• Thestandard VGA device28 and the highperformance VGA device30 are installed at the position substantially adjacent to theextension connector part22 for the port replicator. These VGA devices can put out their performance more sufficiently when they are closer to theextension connector part22. TwoVGA devices28,30 are substantially adjacent to theextension connector part22 in thenote PC1, the VGA devices can put out their performance sufficiently without suffering bad influence of the noise signal. The distance from thestandard VGA device28 to theextension connector part22 and the distance from the highperformance VGA device30 to theextension connector part22 are approximately the same. Thus, the transmission quality of the image signal is approximately the same in the note PC for domestic market and in that for overseas market.
• [The Explanation of a Notebook Type Personal Computer For Domestic Market]
• As anote PC1 for domestic (Japanese) market does not need high performance VGA function and Bluetooth function, the electronic devices for overseas only are not installed on themotherboard24. The floppydisk drive unit40 is installed in themain unit4, because it is demanded instead of the electronic devices for overseas only. As the highperformance VGA device30 is not installed, theheat sink unit38 is not installed either. The floppydisk drive unit40 is installed above the specific area A. As the devices for overseas only are not installed, the floppydisk drive unit40 can be arranged right above and very close to themotherboard24, themain unit4 of thenote PC1 for domestic market can be thin. As the results, the package of themain unit4 can be used in common for domestic market and for overseas market. The size of the package can be reduced to approximately 333 mm×285 mm×38 mm. The area of the specific area A is more than the area of the floppydisc drive unit40 projected to themotherboard24. Therefore, the floppydisk drive unit40 can be arranged in the range of the specific area A.
• By arranging the electronic devices for overseas only in the specific area A unitedly as previously explained, the floppydisk drive unit40 can be arranged in the range of the specific area A with achieving the thin main unit of thenote PC1 for domestic market that does not include the electronic devices for overseas only. Therefore, themotherboard24 can be used in common in thenote PC1 for overseas market and for domestic market.
• Further, the present invention is not limited to this preferred embodiment, and various variations and modifications may be made without departing from the scope of the present invention. For example, the present invention is not limited to the notebook type personal computer, but can be applied to other various electronic apparatuses such as different types of computers or handy data processing units.
• According to the present invention, the circuit board can be used in common, for example, for a plurality of grades or for domestic market and for overseas market. It is not necessary to produce many kinds of the circuit boards for one series of the electronic apparatus. Therefore, it can decrease the production cost and increase the assembling performance. If a function is not installed in the electronic apparatus for domestic market and the same function is installed in that for overseas market, a plurality of the electronic devices in relation to the function are not installed on the circuit board for domestic market and are installed on that for overseas market. Arranging these electronic devices in the specific area unitedly can generate an empty area that has no electronic devices on the circuit board for domestic market. Thus, it will be easy to install other functions or other units that is necessary for domestic market but not necessary for overseas market in the empty area on the circuit board.

Claims (8)

1-10. (canceled)

11. A circuit board which is used in common for a first electronic apparatus having a first configuration and for a second electronic apparatus having a second configuration different from the first configuration, said circuit board comprising:

a common area on the circuit board that is mounted with a CPU and a standard display device that are commonly used for the first and second electronic apparatuses; and

an optional area on the circuit board different from the common area on the circuit board, the optional area on the circuit board being mounted with one of a first electronic device that is unique to the first electronic apparatus and a second electronic device that is unique to the second electronic apparatus;

wherein an extension connector part is installed on the circuit board, said extension connector connects an extension unit that is removably attachable to the first electronic apparatus and the second electronic apparatus.

12. The circuit board according toclaim 11, wherein the extension connector part is installed substantially adjacent to both the install position of the second electronic device on the circuit board and the install position of the third electronic device on the circuit board.

13. The circuit board according toclaim 12, wherein the second electronic device is installed at a position in the area so that the distance between the extension connector part and the second electronic device is substantially the same as the distance between the extension connector part and the third electronic device.

14-15. (canceled)

16. The circuit board according toclaim 11, wherein the extension unit is a connection apparatus that has a plurality of connectors for peripheral apparatuses.

17. The circuit board according toclaim 16, wherein the connection apparatus that has a width substantially the same as the width of the electronic apparatus is removably attachable to the back face of the electronic apparatus, and said connection apparatus has a projection part on which a connector being connectable to the extension connector part is located.

18-22. (canceled)

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