Patent Publication Number: US-8542484-B2

Title: Electronic apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2008-235239 filed on Sep. 12, 2008, the entire contents of which are incorporated herein by reference. 
     FIELD 
     The embodiment described herein relates to an electronic apparatus including a housing for accommodating electronic components. 
     BACKGROUND 
     Recently, screws used in the assembling of an electronic apparatus are reduced in size due to the size reduction of the electronic apparatus. A personal computer, which is an electronic apparatus, accommodates various electronic components in a housing. The housing includes openings such as an exhaust opening for radiating heat generated in the electronic components and a loading opening for loading a small recording medium. The housing of an electronic apparatus is assembled by a plurality of parts connected by screws. 
     When a screw enters the electronic apparatus through a hole provided in the housing during the production or repair of the electronic apparatus, an operator needs to disassemble the assembled electronic apparatus to remove the screw, resulting in reduction of workability of production and repair of the electronic apparatus. Further, the screw may cause accidents such as breakage of electric components and short circuits. 
     With regard to the above problem, Japanese Patent Laid-Open Publication No. 2-161797 discloses that in order to prevent the components from entering the housing, the slit width of an exhaust opening is rendered smaller than other components such as a screw. Further, there has been known an electronic apparatus housing including an openable and closable shutter attached to, for example, a loading opening for a small recording medium. When the small recording medium is not loaded in the loading opening, the shutter closes the loading opening to prevent foreign matter such as dust from entering the housing. 
     The electronic components such as a battery pack and a hard disk drive may be attached to and detached from the electronic apparatus body even after shipment of the electronic apparatus. Thus, it is preferable that an operator can attach and detach electronic components to and from the electronic apparatus body without disassembling the housing fastened with screws. This requirement may be realized by providing, in a housing, an opening for loading the electronic components, such as a battery pack and a hard disk drive, and a lid for closing the opening. This technique may realize ease of exchange of the battery pack and the hard disk drive and may reduce problems caused by foreign matter entering the housing through the opening. 
     The battery pack and the hard disk drive are larger in size than other electronic components mounted in a personal computer which is an electronic apparatus. Therefore, a large opening for loading the battery pack and the hard disk drive is inevitably formed in the housing. Thus, when a lid is opened in the production or repair of the electronic apparatus, if a screw falls into the opening, the screw may enter the back of the housing. In this case, in order to remove the screw having fallen into the opening, an operator should remove screws to disassemble the housing. In many cases, the hard disk drive is inserted into the housing through an opening to be mounted on a substrate, and thereafter to be screwed onto the substrate. Thus, in particular, screws easily enter the housing through the opening for a hard disk. In the above example, although the electronic components are attached to the electronic apparatus with screws, the above problem may also occur with other fastener components using other structures, such as a press-fit pin. 
     SUMMARY 
     According to an aspect of an embodiment, an electronic apparatus includes a circuit board; a housing which incorporates the circuit board and includes, on the bottom surface of the housing, an opening, through which a portion of one surface of the circuit board is visible, and a fastening hole; an electronic component mounted in the opening and accommodated in the housing; and a fastening member inserted into the fastening hole and fixing the housing. The housing has a rib formed along the entire circumference of the opening, and the rib extends from the circumferential edge of the opening toward the circuit board and prevents the fastening member that has fallen into the opening from entering the housing. 
     Additional aspects and/or advantages will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the invention. 
     The above-described embodiments of the present invention are intended as examples, and all embodiments of the present invention are not limited to including the features described above. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  depicts an appearance of a personal computer which is a specific first embodiment of an electronic apparatus; 
         FIG. 2  depicts an appearance of a personal computer with a display unit closed; 
         FIG. 3  depicts a rear surface and a side surface of a personal computer; 
         FIG. 4  depicts a bottom view of a personal computer; 
         FIG. 5  depicts a state where a cover for a disk storage opening is removed from a main housing; 
         FIG. 6  depicts a state where a hard disk drive is removed from a disk storage opening; 
         FIG. 7  depicts a hard disk drive; 
         FIG. 8  depicts a rear side view of a lower cover; 
         FIG. 9  is an enlarged view near a disk storage opening in a lower cover; 
         FIG. 10  depicts an upper housing with a lower cover removed; 
         FIG. 11  is an enlarged view near a disk storage with a hard disk drive removed from a disk storage opening; 
         FIG. 12  is an enlarged view near a keyboard of a personal computer; 
         FIG. 13  depicts the keyboard removed from a personal computer; 
         FIG. 14  depicts a main unit when the keyboard is removed; 
         FIG. 15  is an enlarged view near a supporting portion of an upper housing; 
         FIG. 16  depicts a supporting portion; 
         FIG. 17  depicts a rear surface of an upper housing with the supporting portion attached; 
         FIG. 18  is a conceptual diagram depicting a keyboard mounted on a mounting plate; 
         FIG. 19  depicts a first surface (lower surface) of a circuit board mounted with connectors; 
         FIG. 20  depicts a second surface (upper surface) of a circuit board; 
         FIG. 21  depicts an optical disk drive accommodated in a main housing; 
         FIG. 22  depicts an optical disk drive; 
         FIG. 23  depicts a holding member; 
         FIG. 24  depicts an optical disk drive mounted with a holding member; 
         FIG. 25  is a view of an optical disk drive viewed from an oblique direction; 
         FIG. 26  depicts an area near an expansion card slot of an upper housing with a lower cover removed; 
         FIG. 27  depicts an upper surface of a circuit board with an expansion card holding member attached thereto; 
         FIG. 28  is a view of an expansion card holding member viewed obliquely downward; 
         FIG. 29  is a view explaining existing troubles occurring when an expansion card is loaded; 
         FIG. 30  is an outside view near an expansion card slot of an upper housing with a circuit board removed; 
         FIG. 31  is an inside view of the expansion card slot; 
         FIG. 32  depicts an inserted expansion card; 
         FIG. 33  depicts an expansion card held by an expansion card holding portion; 
         FIG. 34  is an enlarged view near a filter storage opening of a bottom surface of a personal computer; 
         FIG. 35  depicts a dust filter; 
         FIG. 36  depicts a filter storage opening with a dust filter removed; 
         FIG. 37  is an enlarged view of a portion corresponding to the filter storage opening in a main housing; 
         FIG. 38  depicts a mounted dust filter; 
         FIG. 39  depicts a heat radiating member and a fan connected by a supporting portion; 
         FIG. 40  is a cross-sectional view of a personal computer near a heat radiating member and a fan mounted on a personal computer, and 
         FIG. 41  is a view of a dust filter and heat radiating fins as viewed from the side of an inlet. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENT 
     Hereinafter, an embodiment will be described with reference to the drawings. 
       FIG. 1  depicts an appearance of a personal computer  10  which is a specific first embodiment of an electronic apparatus. 
     The personal computer  10  includes a main unit  20  and a display unit  30 . The display unit  30  is connected to the main unit  20  by a hinge  40  such that the display unit may be opened and closed.  FIG. 1  is a front view of the personal computer  10  with the display unit  30  opened. 
     The main unit  20  is used for executing various information processes. The main unit  20  includes a CPU and a hard disk device accommodated in a main housing  21 . The main housing  21  includes on its upper surface a keyboard  22 , a trackpad  23 , a left button  24 , and a right button  25 . The main housing  21  further includes a fingerprint sensor  26  provided between the left button  24  and the right button  25 . A fingertip is swept across the fingerprint sensor  26 , whereby fingerprint authentication is performed. 
     A result of the information processing performed by the main unit  20  is displayed on the display unit  30 . The display unit  30  includes a display housing  31 . The display housing  31  accommodates a thin liquid crystal panel, which has an image screen  32  on the front surface, a control circuit for the liquid crystal panel, and a communication antenna. 
       FIG. 2  depicts an appearance of the personal computer  10  with the display unit  30  closed. 
     When the display unit  30 , as depicted in  FIG. 2 , is closed with respect to the main unit  20  to shield the image screen  32  inside the display unit  30 , a user may compactly carry the personal computer  10  without contaminating or damaging the image screen  32 . 
       FIG. 3  depicts a rear surface and a side surface of the personal computer  10 . 
     The main unit  20  includes, on its rear surface, a radiation outlet  220  and connector openings  221   a  and  222   a  for connector fitting. A LAN cable connector  221  and a USB connector  222  are exposed by the connector openings  221   a  and  222   a , respectively. The main unit  20  further includes on its side surface an expansion card slot  210  and a modem connector  223 . The expansion card slot  210  is used for loading an expansion card for function expansion, such as a LAN card. The main unit  20  further includes, on the side surface opposite the side surface depicted in  FIG. 3 , an optical disk storage opening (not shown) for loading an optical disk such as a CD and a DVD. 
       FIG. 4  depicts the bottom surface of the personal computer  10 . 
     A keyboard  22  (see  FIG. 1 ) is fitted into the upper surface of the main housing  21  of the main unit  20 . The main housing  21  is made up of an upper housing  211  with a circuit board fixed to the rear surface of the keyboard  22  and a lower cover  212  mounted on the upper housing  211 . The main housing  21  includes a battery storage opening  231 , a disk storage opening  241 , and a filter storage opening  251 . A battery pack is inserted into the battery storage opening  231 . A hard disk drive is inserted into the disk storage opening  241 . A dust filter  252  is loaded in the filter storage opening  251 . A disk cover  242  is loaded in the disk storage opening  241 . A battery cover  232  is loaded in the battery storage opening  231 . 
     The personal computer  10  is basically configured as above. 
     Subsequently, each component of the personal computer  10  will be described in detail. 
     (Configuration of the Disk Storage Opening for Loading a Hard Disk Drive) 
     First, a configuration of the disk storage opening  241  loaded with a hard disk drive and the inside of the main housing  21  will be described. 
     The personal computer  10  includes: 
     a circuit board; 
     a housing which incorporates the circuit board and includes, on the bottom surface of the housing, an opening, through which a portion of one surface of the circuit board is visible, and a fastening hole; 
     an electronic component loaded into the opening and accommodated in the housing; and 
     a fastening member inserted into the fastening hole and fixing the housing. 
     The housing has a rib which extends from the circumferential edge of the opening toward the circuit board over the entire circumference of the opening and prevents the fastening member that has fallen into the opening from entering the housing. 
       FIG. 5  depicts a state where the disk cover  242  for the disk storage opening  241  is removed from the main housing  21 . 
     A hard disk drive unit  310  is fitted into the disk storage opening  241 . The hard disk drive unit  310  is loaded into the disk storage opening  241 , and thereafter, fixed to the main housing  21  by a plurality of screws  312 . The hard disk drive unit  310  includes a hard disk drive  320  and a mounting member  330  for fixing the hard disk drive  320  to the main housing  21 . After the hard disk drive unit  310  is fixed to the main housing  21 , a disk cover  242  depicted in  FIG. 4  is attached to the main housing  21 . The main housing  21  is an example of the housing. The disk storage opening  241  is an example of the opening. The screws  312  are examples of the fastening member. The hard disk drive unit  310  is an example of the electronic component. 
       FIG. 6  depicts a state where the hard disk drive unit  310  is removed from the disk storage opening  241  illustrated in  FIG. 5 .  FIG. 7  depicts the hard disk drive unit  310 . 
     As depicted in  FIG. 6 , when the hard disk drive unit  310  is not mounted, a portion of a circuit board  400  is exposed from the disk storage opening  241  of the main housing  21 . As described above, the hard disk drive unit  310  includes the hard disk drive  320  and the mounting member  330 . As depicted in  FIG. 7 , the mounting member  330  is attached to the hard disk drive  320  by a screw penetrating through a hole, provided in the side surface of the mounting member  330 , to be fastened into a threaded hole provided in the side surface of the hard disk drive  320 . The mounting member  330  includes plates  331  and  332  at the both ends in the longitudinal direction of the hard disk drive  320 . The plate  331  includes a plurality of holes  311 . The main housing  21  includes threaded holes  411  in positions corresponding to the plurality of holes  311  of the plate  331 . The screws  312  depicted in  FIG. 5  penetrate the holes  311  of the mounting member  330  to be fastened into the threaded holes  411  of the main housing  21 , whereby the hard disk drive unit  310  is fixed to the main housing  21 . The circuit board  400  is an example of the circuit board. The threaded hole  411  of the main housing  21  is an example of the fastening hole. 
     The main housing  21  further includes a rib  412  provided by extending an edge of the disk storage opening  241  toward the circuit board  400 . 
     Holes  413  provided in the lower cover  212  are used for attaching the lower cover  212  to the upper housing  211  by a screw penetrating through the hole  413  and a hole  414  of the circuit board  400  depicted in  FIG. 10  to be fastened into a hole provided in the upper housing  211 . 
     As described above, the plate  331 , which is one end of the mounting member  330 , is fixed to the main housing  21  by the screws  312 , and the plate  332 , which is the other end, is pressed by the disk cover  242  so as to be fixed to the main housing  21 . 
       FIG. 8  depicts a rear surface side of the lower cover  212 .  FIG. 9  is an enlarged view near the disk storage opening  241  in the lower cover  212 . 
     As illustrated in  FIGS. 8 and 9 , the rib  412  is formed on the lower cover  212  around the entire circumference of the disk storage opening  241 . Since the rib  412  extends toward the circuit board  400 , the space connecting the disk storage opening  241  to the inside of the main housing  21  is narrow. The rib  412  is an example of the rib. 
       FIG. 10  depicts the upper housing  211  with the lower cover  212  removed. 
     As illustrated in  FIG. 10 , the circuit board  400  is fitted into the upper housing  211 . A heat radiating member  430  for radiating heat generated in various electronic components and a fan  420  for blowing air are disposed on the circuit board  400  next to a position P on the circuit board  400  mounted with the hard disk drive unit  310 . Namely, the heat radiating member  430  and the fan  420  are disposed at a position where the rib  412  is located between them and the hard disk drive unit  310 . 
       FIG. 11  is an enlarged view near the disk storage opening with the hard disk drive unit  310  removed from the disk storage opening  241  illustrated in  FIG. 6 . 
     As depicted in  FIG. 11 , the rib  412  extends from the edge of the disk storage opening  241  toward the circuit board  400 . Even if the screw  312  falls into the disk storage opening  241 , the rib  412  prevents the screw  312  from entering the main housing  21 . According to this configuration, an operator can immediately find the screw  312  and remove the screw from the main housing  21 . 
     In this embodiment, the electronic component is preferably a hard disk drive. 
     The hard disk drive  320  may be attached and detached after shipment of the personal computer  10 . Therefore, the disk storage opening  241  is provided in the main housing  21 , and the hard disk drive  320  is inserted into the disk storage opening  241  to be thereafter fastened by screws. Therefore, the screws  312  may easily fall into the disk storage opening  241  during the production or repair of the personal computer  10 . However, in this embodiment, a path from the inside of the opening to the inside of the housing is closed or narrowed by the rib  412 , and trouble caused by the screws  312  entering the main housing  21  may be reduced if not prevented, and thus the need to disassemble the main housing  21  in order to find the screws  312  is greatly reduced if not prevented. 
     It is preferable that a gap is provided between the circuit board and the rib. It is further preferable that a fan forming an air flow through the gap is provided at a position so that the rib is between the fan and the electronic component. 
     In this embodiment, as illustrated in  FIG. 11 , a gap S is provided between the rib  412  and the circuit board  400 . The hard disk drive  320  usually generates more heat than other electronic components mounted in the personal computer  10 . In this embodiment, air containing the heat generated in the hard disk drive  320  is guided through the gap S to the heat radiating member  430  by the fan  420  depicted in  FIG. 10 , and then is discharged outside the main housing  21 . In this way, this embodiment achieves highly efficient radiation. 
     In this embodiment, the screws are used as an example of the fastening member; however, other kinds of fasteners such as a press-fit pin may be used. 
     The description of the configuration of the disk storage opening  241  ends here. 
     (Method for Mounting a Keyboard) 
     Subsequently, a method for mounting the keyboard  22  to the main housing  21  will be described. 
     The personal computer  10  includes: 
     a keyboard having a plurality of keys arranged on an upper surface and a rib, a long side of the keyboard extending in left and right directions, the rib protruding from the long side of the keyboard except at left and right ends; 
     a supporting portion to support a lower surface at the left and right ends of the keyboard; and 
     a fixing portion to fix the rib of the keyboard, 
     wherein the supporting portion supports the lower surface at the left and right ends of the keyboard so that the lower surface of the keyboard protrudes downward. 
       FIG. 12  is an enlarged view near the keyboard  22  of the personal computer  10 . 
     The upper housing  211  of the main housing  21  includes an opening  511  on the upper surface. The keyboard  22  is mounted in the opening  511 . The keyboard  22  is an example of the keyboard. 
       FIG. 13  depicts the keyboard  22  removed from the personal computer  10 .  FIG. 14  depicts the main unit  20  with the keyboard  22  removed from the personal computer  10 . 
     The keyboard  22  is formed of a generally soft flexible resin. The keyboard  22  includes a sheet and a plurality of keys  22   a  disposed on the sheet in a predetermined arrangement. The keyboard  22  further includes a thin metal plate on the lowermost surface of the keyboard for reinforcement. The keyboard  22  further includes a plurality of ribs  22   b  in a central portion other than the left and right ends on the circumferential edges of the front and back sides of the keyboard  22 . The ribs  22   b  are used for mounting the keyboard  22  to the upper housing  211  of the main unit  20 . The rib  22   b  is an example of the rib. 
     As depicted in  FIG. 14 , the upper housing  211  includes an opening  511  on the upper surface. A mounting plate  501  for fixing the keyboard  22  is fixed into the opening  511 . The mounting plate  501  includes rib holes  541 . The ribs  22   b  of the keyboard  22  are fixed into the rib holes  541 . The mounting plate  501  further includes a plastic bulkhead portion  530  and a metal supporting portion  520 . The bulkhead portion  530  partitions various electronic components and the keyboard  22 . The supporting portion  520  is detachably attached to the left and right ends of the bulkhead portion  530 . The rib holes  541  are an example of the fixing portion. The supporting portion  520  is an example of the supporting portion. 
     The supporting portion is preferably a metal material. The support portion further preferably includes a second supporting portion for supporting the lower surface of the keyboard in a area closer to the center than the left and right ends supported by the supporting portion. 
     In this embodiment, the central portion of the mounting plate  501  is made up of the plastic bulkhead portion  530  so that the personal computer  10  is reduced in weight. Further, in this embodiment, the left and right ends of the mounting plate  501  are made up of the metal supporting portion  520  so that the supporting strength of the keyboard  22  is enhanced, and when the keys are pressed, a good clicking feeling is realized. The bulkhead portion  530  is an example of the second supporting portion. 
     The configurations of the upper housing  211  and the supporting portion  520  will be described in detail. 
       FIG. 15  is an enlarged view near the supporting portion  520  of the upper housing  211 . 
     The bulkhead portion  530  includes the rib holes  541  into which the ribs  22   b  of the keyboard  22  are fixed. The bulkhead portion  530  further includes a plurality of openings  531   a  and  531   b . The supporting portion  520  further includes a plurality of protrusions  521  projecting upward and provided at a portion closer to the end of the upper housing  211  than the endmost rib hole  541  in the arrangement direction. 
       FIG. 16  depicts the supporting portion  520 .  FIG. 17  depicts a rear surface side of the upper housing with the supporting portion  520  attached. 
     The supporting portion  520  includes a housing fixing portion  523  and a hinge fixing portion  522 . The housing fixing portion  523  is fixed to the upper housing  211 . The hinge fixing portion  522  is fixed to the hinge  40 . As depicted in  FIG. 17 , the hinge fixing portion  522  of the supporting portion  520  is connected to the hinge  40  and extends in a direction away from the hinge  40 . In this embodiment, the metal supporting portion  520  and the hinge  40  are connected to each other so that other metal components for fixing the hinge  40  and the upper housing  211  are not required to be provided, and the fixing strength of the hinge  40  is enhanced while reducing the number of components. 
       FIG. 14  will be described again. 
     As depicted in  FIG. 14 , the mounting plate  501  has such a structure that the metal supporting portion  520  is attached to the left and right sides of the light and soft bulkhead portion  530 . Further, in the mounting plate  501 , an optical disc drive  810 , a holding member  811  for the optical disc drive  810 , the circuit board  400 , a connector stiffening member  820 , and the fan  420  are partially visible from a plurality of openings  531   a ,  531   b ,  531   c ,  531   d ,  531   e , and  531   f  provided in the bulkhead portion  530 . 
       FIG. 18  is a conceptual diagram depicting the keyboard  22  mounted on the mounting plate  501 . 
       FIG. 18A  is an upper view of the mounting plate  501  and the keyboard  22 . As depicted in  FIG. 18A , the ribs  22   b  of the keyboard  22  are inserted into the rib holes  541  of the bulkhead portion  530  so that the keyboard  22  is mounted on the mounting plate  501 . The keyboard  22  has elasticity. According to this configuration, the ribs  22   b  are fixed to the rib holes  541 , and the left and right ends of the keyboard  22  are pressed upward by the protrusions  521  of the supporting portion  520  so that the central portion of the keyboard  22  is pressed downward against the mounting plate  501 . In this embodiment, the central portion of the keyboard  22  is pressed against the mounting plate  501  by utilizing the elasticity of the keyboard  22  to suppress floating of the keyboard  22 . According to this configuration, this embodiment prevents the sinking of the key when the keyboard is pressed and provides good key operability for a long period of time. 
     It is preferable that the supporting portion has, on its upper surface, a plurality of protrusions aligned in the short side direction of the keyboard, and that the keyboard is supported with the lower surfaces of the left and right ends of the keyboard raised by the protrusions. 
     The protrusions  521  press up both ends of the keyboard  22  to thereby increase the contact between the keyboard  22  and the metal supporting portion  520 , whereby the keyboard  22  is reliably electrically connected. 
     Here, there will be described another method for pressing up the left and right ends of the keyboard  22  and supporting the keyboard so that the lower surface of the keyboard is protruding downward. 
       FIGS. 18B ,  18 C, and  18 D are cross-sectional views of a mounting plate and a keyboard different from those of  FIG. 18A . 
     The supporting portion has on its upper surface a rib extending in the short side direction of the keyboard, and the keyboard may be supported so that the lower surfaces of the left and right ends of the keyboard are lifted by the rib. 
     In  FIG. 18B , instead of the protrusions  521 , a rib  5211  extending in a depth direction (short side direction of the keyboard  22 ) is provided on a supporting portion  5201 . The rib  5211  lifts the left and right ends of the keyboard  22 . The rib  5211  extending in the depth direction is formed in the supporting portion  5201  so that the left and right ends of the keyboard  22  may be reliably pushed upward. 
       FIG. 18C  depicts a mounting plate  5012  in which a metal supporting portion  5202  is placed on a plastic bulkhead portion  5302 . Although protrusions are not provided in the supporting portion  5202 , the supporting portion  5202  has a step with respect to the bulkhead portion  5302 . The step presses up the left and right ends of the keyboard  22 . The mounting plate  5012  has a step at portions facing the left and right ends of the keyboard  22  to thereby prevent the deflection of the keyboard  22 . 
     It is also preferable that the supporting portion has on its upper surface slopes that slope upward from the central portion of the keyboard toward the left and right ends, and that the keyboard is supported so that the lower surfaces of the left and right ends of the keyboard are pushed upward by the slopes. 
     In  FIG. 18D , the mounting plate  5013  is made up of only the plastic bulkhead portion  5303 , and the bulkhead portion  5303  has slopes that slope upward formed from the central portion of the keyboard  22  toward the left and right ends. The slope of the bulkhead portion  5303  may push the left and right ends of the keyboard  22  upward. 
     The description of the method for mounting the keyboard ends here. 
     (Connector Stiffening Member) 
     Subsequently, the connector stiffening member  820  also depicted in  FIG. 14  will be described. 
     The personal computer  10  includes: 
     a circuit board including a connector mounted at an end edge and a metal member reinforcing the connector, the connector including a fitting surface of the connector facing outside; 
     a housing which accommodates the circuit board and includes a first opening for a keyboard arrangement formed in an upper surface thereof and a second opening for fitting with a mating connector formed on a side surface thereof, the second opening facing the fitting surface of the connector mounted on the circuit board; and 
     a keyboard exposed to the outside from the first opening and having a plurality of keys arranged on an upper surface thereof. 
     The metal member extends under the keyboard and supports a portion of the lower surface of the keyboard. 
       FIG. 19  depicts a first surface (lower surface) of the circuit board  400  mounted with connectors  221  and  222 . 
     The connectors  221  and  222  are mounted on the first surface (lower surface) side of the circuit board  400  so that the fitting surfaces of the connectors face outward. The connector stiffening member  820  for preventing trouble due to static electricity and reinforcing the connectors  221  and  222  is attached to the connectors  221  and  222 . The connectors  221  and  222  are fitted into the connector openings  221   a  and  222   a  for the connector fitting depicted in  FIG. 3 . The connectors  221  and  222  are examples of the connectors. The connector stiffening member  820  is an example of the metal member. The connector openings  221   a  and  222   a  for connector fitting are examples of the second opening. The opening  511  for the arrangement of the keyboard  22  depicted in  FIG. 14  is an example of the first opening. 
       FIG. 20  depicts a second surface (upper surface) of the circuit board  400  depicted in  FIG. 19 . 
     As depicted in  FIG. 20 , the connector stiffening member  820  wraps around the first surface (lower surface) side of the circuit board  400  and extends to the second surface (upper surface). The circuit board  400  is mounted into the main housing  21  so that the second surface faces upward. Consequently, as depicted in  FIG. 14 , the circuit board  400  is disposed at a position facing the lower surface of the keyboard  22 , and a portion of the connector stiffening member  820  is exposed from an opening  531   f  provided in the mounting plate  501 . 
     As a preferred embodiment, the connector is mounted on a first surface of the circuit board facing the bottom surface side of the housing, and the metal member includes a first portion reinforcing the connector on the first surface side and a second portion which wraps around and extends from the first surface side to the second surface side of the circuit board and supports the keyboard. 
     It is also preferable to provide an opening from which the metal member facing the lower surface of the keyboard is partially exposed, and to provide a mounting member which supports the keyboard in cooperation with the metal member with the lower surface of the keyboard placed on the mounting member. 
     When the keyboard  22  is mounted on the mounting plate as depicted in  FIG. 14 , the connector stiffening member  820  exposed by the opening  531 f is in contact with the lower surface of the keyboard  22 . Thus, the connector stiffening member  820  for reinforcing the connectors  221  and  222  extends under the keyboard  22  to support the lower surface of the keyboard  22 . Therefore, in this embodiment, the strength for supporting the keyboard  22  may be enhanced without increasing the number of components, and a good clicking feeling may be provided. Further, the metal connector stiffening member  820  is in contact with the keyboard  22 , whereby the keyboard  22  is reliably electrically connected. 
     The description of the connector stiffening member ends here. 
     (Optical Disc Drive) 
     Subsequently, the optical disc drive  810  also depicted in  FIG. 14  will be described. 
       FIG. 21  depicts the optical disc drive  810  accommodated in the main housing  21 . 
     The metal holding member  811  is attached to the optical disc drive  810 . The holding member  811  is fixed to the lower cover  212  of the main housing  21  to be thereby mounted on the lower cover  212 . 
       FIG. 22  depicts the optical disc drive  810 .  FIG. 23  depicts the holding member  811 .  FIG. 24  depicts the optical disc drive  810  mounted with the holding member  811 . 
     The optical disc drive  810  has a thin plate shape. The holding member  811  has a side portion  811   a , an upper surface portion  811   c , and a fixing portion  811   b . The side portion  811   a  holds the side surface of the optical disc drive  810 . The upper surface portion  811   c  holds the upper surface of the optical disc drive  810 . The fixing portion  811   b  is fixed to the lower cover  212 . When the holding member  811  is mounted on the optical disc drive  810 , the upper surface portion  811   c  of the holding member  811  wraps around and extends onto the upper surface of the optical disc drive  810 . 
       FIG. 25  is a view depicting the optical disc drive  810  depicted in  FIG. 21  as viewed from the oblique direction. 
     When the optical disc drive  810  is mounted on the lower cover  212  of the main housing  21 , the upper surface portion  811   c  of the holding member  811  is positioned higher than the upper surface of the optical disc drive  810 . The upper housing  211  is mounted on the lower cover  212  as depicted in  FIG. 25 , and the keyboard  22  is mounted on the mounting plate  501 . According to this configuration, as depicted in  FIG. 14 , the holding member  811  exposed by the opening  531   b  supports the lower surface of the keyboard  22 , and therefore, the fixing strength of the keyboard  22  may be enhanced. 
     The description of the optical disc drive ends here. 
     (Expansion Card Slot) 
     Subsequently, the configuration of the expansion card slot  210  also depicted in  FIG. 3  will be described. 
     The personal computer  10  includes: 
     a circuit board; 
     a housing accommodating the circuit board and having a card insertion slot on a side surface thereof; and 
     a card holding portion fixed on the circuit board and having a card receiving slot facing the card insertion slot and provided closer to a center side of the circuit board than a side edge of the circuit board on the card insertion slot side. 
     The card holding portion receives a card, inserted through the card insertion slot, from the card receiving slot and holding the card. 
     The housing has a guiding rib which extends from the card insertion slot to the vicinity of the card receiving slot and guides the card, inserted into the card insertion slot, to the card receiving slot. 
       FIG. 26  depicts an area near the expansion card slot  210  of the upper housing  211  with the lower cover  212  detached. 
     The expansion card slot  210  is provided in the side surface of the upper housing  211 . An expansion card is inserted through the expansion card slot  210  and mounted in parallel along the circuit board  400 . The expansion card slot  210  is an example of the card insertion slot. 
       FIG. 27  depicts the upper surface of the circuit board  400  with an expansion card holding member.  FIG. 28  is a view of the expansion card holding member viewed obliquely downward. 
     As depicted in  FIG. 27 , the expansion card holding member  610  is fixed onto the circuit board  400  so that the card receiving slot  611  faces the expansion card slot  210  of the upper housing  211 . The card receiving slot  611  is an example of the card receiving slot. The expansion card holding member  610  is an example of the card holding portion. As depicted in  FIG. 28 , a gap S is provided between the expansion card holding member  610  and the circuit board  400 . A processor chip  400   a  (see  FIG. 27 ) is mounted in the mounting region of the expansion card holding member  610  of the circuit board  400  by utilizing the gap S. 
     It is preferable that the card holding portion holds a card with a gap between the card holding portion and a circuit board. 
     The processor chip  400   a  is mounted in the gap S provided between the expansion card holding member  610  and the circuit board  400  so that the entire device size is reduced. 
     As depicted in  FIG. 28 , the expansion card holding member  610  is disposed closer to the inside than an edge Q of the circuit board  400 , and a gap is formed between the card receiving slot  611  and the expansion card slot  210 . 
       FIG. 29  is a view explaining existing trouble occurring when the expansion card is loaded. 
     As depicted in  FIG. 28 , when the card receiving slot  611  and the expansion card slot  210  are provided with a distance therebetween, the expansion card is not guided from the expansion card slot  210  to the card receiving slot  611 . Therefore, the expansion card may obliquely enter the expansion card slot  210 , whereby, as depicted in  FIG. 29 , the expansion card  620  may not enter the card receiving slot  611  but enter a gap between the expansion card holding member  610  and the circuit board  400 . The expansion card  620  entering the gap may be caught by the expansion card holding member  610 , whereby the expansion card  620  may be difficult to remove from the expansion card slot  210 . In this embodiment, such a trouble is prevented by a guiding rib  630  (see  FIG. 30 ) which guides the expansion card  620 , inserted into the expansion card slot  210 , to the card receiving slot  611 . 
       FIG. 30  is an outside view of the vicinity of the expansion card slot  210  of the upper housing  211  with the circuit board  400  removed.  FIG. 31  is an inside view of the expansion card slot  210 . 
     As depicted in  FIGS. 30 and 31 , the upper housing  211  includes the guiding rib  630  extending from the expansion card slot  210  to the inside of the housing. The guiding rib  630  extends from the edge, which is closer to the circuit board  400  of the expansion card slot  210 , to a position near the card receiving slot  611  of the expansion card holding member  610 . 
       FIG. 32  depicts the insertion of the expansion card  620  in this embodiment.  FIG. 33  depicts the expansion card  620  held by the expansion card holding member  610 . 
     In this embodiment, the expansion card  620  inserted into the expansion card slot  210  is guided to the card receiving slot  611  by the guiding rib  630 , and held parallel to the circuit board  400  by the expansion card holding member  610 . Therefore, the trouble that the expansion card  620  is obliquely inserted into the expansion card slot  210  to be caught in the gap S (see  FIG. 28 ) between the expansion card holding member  610  and the circuit board  400  is reduced if not prevented, and the expansion card  620  is easily and properly loaded. Further, since the guiding rib  630  is formed in the housing, increases in the device size and cost due to an increase in the number of components is reduced. 
     It is preferable that the card holding portion holds a card parallel to a substrate, and that the guiding rib extends between the card held by the card holding portion and the substrate. 
     The guiding rib  630  is formed on the side of the expansion card slot  210 , which is closer to the circuit board  400 , whereby the guiding rib  630  is positioned between the expansion card  620  held by the expansion card holding member  610  and the circuit board  400 . According to this configuration, since the guiding rib  630  blocks the path to the gap S depicted in  FIG. 28 , such a trouble that the expansion card  620  enters the gap S may be reliably prevented. 
     The description of the configuration of the expansion card slot  210  ends here. 
     (Mounting Configuration of Dust Filter) 
     Subsequently, the mounting configuration of the dust filter  252  also depicted in  FIG. 4  will be described. 
     The personal computer  10  includes: 
     a housing including an outlet formed in a first surface thereof and a filter storage opening formed in a second surface thereof extending to intersect with the first surface; 
     a heating electronic component disposed in the housing; 
     a heat radiating member disposed closer to the outlet than the filter storage opening in the housing, the heat radiating member having an inlet on the filter storage opening side and an outlet on the outlet side and radiating heat received from the heating electronic component to the air flowing through the inlet; 
     a filter member inserted into the housing through the filter storage opening and disposed on the front surface of the inlet; 
     a filter receiving portion; and 
     a fan disposed at a position in the housing where the filter member is held between the fan and the heat radiating member and feeding air in the housing into the inlet. 
     The filter member includes: 
     a filter portion disposed on the front surface of the inlet and forming a plurality of vents; 
     a tip supporting portion to support the front end of the filter portion; and 
     a lid portion to support the rear end of the filter portion and to close the filter storage opening when the filter member is inserted through the filter storage opening. 
     The filter receiving portion receiving, at a position away from the inlet, the tip supporting portion passing through the front of the inlet when the filter member is inserted through the filter storage opening. 
     The lid portion has such a dimension that the filter storage opening is closed when the tip supporting portion is supported by the filter receiving portion. 
       FIG. 34  is an enlarged view of the vicinity of the filter storage opening  251  on the bottom surface of the personal computer  10  depicted in  FIG. 4 .  FIG. 35  depicts the dust filter  252 . 
     As depicted in  FIG. 34 , the main housing  21  of the personal computer  10  includes the outlet  220  provided on the rear surface side. The main housing  21  includes, on its bottom surface, the filter storage opening  251  through which the dust filter  252  is inserted. The outlet  220  is an example of the outlet. The filter storage opening  251  is an example of the filter storage opening. 
     As depicted in  FIG. 35 , the dust filter  252  includes a lid portion  710 , a tip supporting portion  720 , and a plurality of plate members  730 . The lid portion  710  has a handle  710   a . The tip supporting portion  720  is inserted into the filter storage opening  251 . The plate members  730  are arranged between the lid portion  710  and the tip supporting portion  720  so as to be parallel to each other, and a plurality of vents Q are formed by the plate members  730 . When the dust filter  252  is loaded into the filter storage opening  251  depicted in  FIG. 34 , the filter storage opening  251  is closed by the lid portion  710 . The dust filter  252  is an example of the filter member. The plate members  730  are an example of the filter portion. The tip supporting portion  720  is an example of the tip supporting portion. The lid portion  710  is an example of the lid portion. 
       FIG. 36  depicts the filter storage opening  251  with the dust filter  252  removed. 
     When the dust filter  252  is removed from the filter storage opening  251 , some heat radiating fins  431  (see  FIG. 37 ) of the heat radiating member  430  depicted in  FIG. 10  are exposed by the filter storage opening  251 . 
       FIG. 37  is an enlarged view of a portion corresponding to the filter storage opening  251  in the main housing  21 .  FIG. 38  depicts the mounted dust filter  252 . 
     The heat radiating member  430  and the fan  420  are provided in the main housing  21 . The heat radiating member  430  is disposed closer to the outlet  220  than a filter mounting position P corresponding to the filter storage opening  251 . The fan  420  is disposed further toward the inside of the main housing  21  than the heat radiating member  430 . The heat radiating member  430  and the fan  420  are connected by a supporting portion  910 . The supporting portion  910  includes, at the filter mounting position P, a filter receiving portion  911  to which the tip supporting portion  720  of the dust filter  252  is mounted. 
     The heat radiating member  430  includes an inlet  431   a  and an outlet  431   b . The inlet  431   a  includes a plurality of the heat radiating fins  431  arranged in a row, and the air sent from the fan  420  flows into the inlet  431   a . The outlet  431   b  faces the outlet  220  of the main housing  21 . The heat radiating member  430  is an example of the heat radiating member. The fan  420  is an example of the fan. The inlet  431   a  is an example of the inlet. The outlet  431   b  is an example of the outlet. 
     As depicted in  FIG. 38 , the dust filter  252  is disposed between the fan  420  and the inlet  431   a  of the heat radiating member  430 , and the tip supporting portion  720  is fitted into the filter receiving portion  911 . 
     The air sent from the fan  402  passes through the vents Q formed by the plate members  730  of the dust filter  252  to reach the inlet  431   a  of the heat radiating member  430 . The heat generated in various electronic components is absorbed by a heatsink  433  and transferred to the air flowing through the inlet  431   a . The air absorbing the heat passes through spaces, respectively held by the heat radiating fins  431 , to be discharged outside the housing through the outlet  220 . 
       FIG. 39  depicts the heat radiating member  430  and the fan  420  coupled by the supporting portion  910 . 
     As depicted in  FIG. 39 , the supporting portion  910  has the filter receiving portion  911  provided at a position lower than the lower ends of the heat radiating fins  431  of the heat radiating member  430  and formed in the shape of a groove. The tip supporting portion  720  of the dust filter  252  is fitted into the filter receiving portion  911 . 
     It is preferable to provide a supporting portion which supports the heat radiating member and the fan and includes the filter receiving portion, and it is preferable that the filter receiving portion is formed in the shape of a groove and receives the tip supporting portion. 
     The filter receiving portion  911  is easily formed by forming the shape of a groove in the supporting portion  910  supporting the heat radiating member  430  and the fan  420 . The supporting portion  910  is an example of the supporting portion. 
       FIG. 40  is a cross-sectional view of the personal computer  10  near the heat radiating member  430  and the fan  420  mounted on the personal computer  10 . 
       FIG. 40  depicts the bottom surface of the personal computer  10  turned upward. As depicted in  FIG. 40 , the tip supporting portion  720  of the dust filter  252  enters the filter receiving portion  911  so that the plate members  730  of the dust filter  252  are positioned lower than the heat radiating fins  431  of the heat radiating member  430 . The plate members  730  of the dust filter  252  are longer than the heat radiating fins  431  of the heat radiating member  430 . 
     It is preferable that the heat radiating member has a plurality of heat radiating fins aligned so that the end surfaces of the heat radiating members are positioned at the inlet and the outlet, and that the filter portion includes a plurality of members that extend to a position between the lid portion and the tip supporting portion so as to be parallel to each other and are aligned at a wider interval than the alignment interval of the heat radiating fins. 
     According to the above configuration, the entry of dust into the inlet can be efficiently reduced if not prevented, whereby the blocking of air flow due to the dust filter  252  may be reduced if not prevented. 
       FIG. 41  is a view of the dust filter  252  and the heat radiating fins  431  as viewed from the side of the inlet  431   a.    
     As depicted in  FIG. 41 , an alignment interval W 2  of the plate members  730  of the dust filter  252  is larger than an alignment interval W 1  of the heat radiating fins  431 . Since the plate members  730  of the dust filter  252  are positioned further outside than the both ends of the heat radiating fins  431 , an air flow path formed by the heat radiating fins  431  is not impeded by the lid portion  710  and the tip supporting portion  720  of the dust filter  252 . The air sent by the fan  42  passes through gaps between the plate members  730  of the dust filter  252  to reach the inlet  431   a , and passes through the outlet  431   b  to be discharged from the outlet  220 . Since the blocking of the air flow due to the dust filter  252  is reduced if not prevented, reduction of the heat radiating efficiency due to the mounting of the dust filter  252  is suppressed, and problems caused by dust entering the inlet  431   a  may be reduced if not prevented. 
     In the above embodiment, the personal computer is used as an example of an electronic apparatus. However, the electronic apparatus may be various apparatuses such as a notebook computer, a PDA, a game machine, a television, or a portable telephone. 
     In the above embodiment, although the dust filter uses a plurality of the plate members aligned parallel, a filter portion of the filter member may be formed into, for example, a net. 
     All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the invention and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although the embodiment of the present inventions has been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.