Abstract:
A shield member for an electronic apparatus comprises a contact portion that extends outwardly from the shield member. The shield member is attached to an electronic apparatus slot unit and spans between the slot unit and a radiation unit via the contact portion. The contact portion creates a grounding potential between the slot unit and the radiation member.

Description:
This application claims a priority based on Japanese Patent Application No. 11-257787 filed on Sep. 10, 1999, the entire contents of which are incorporated herein by reference for all purposes. 
     BACKGROUND OF THE INVENTION 
     This invention relates to an electronic apparatus having a slot portion to which connectors etc. of peripheral machines are joined. 
     A housing of an electronic apparatus is provided with a shield adapted to prevent electromagnetic waves generating in an electronic circuit in the interior of the electronic apparatus from leaking to the outside. In the case of an electronic apparatus having a slot portion to which the connectors of peripheral machines are joined, a shield is also provided on the slot portion so as to prevent electromagnetic waves from leaking from an opening of the slot portion to the outside. In general, a shield for a slot portion is grounded by screwing the shield of a shield for the housing. The screwing operation serves also as screwing for fixing a slot portion body to the housing in a certain case. 
     SUMMARY OF THE INVENTION 
     As described above, a shield for a slot portion is generally grounded by screwing the shield together with a slot portion body to a housing of an electronic apparatus. In an electronic apparatus having a certain inner structure, a shield for the housing is not provided around the slot portion or a shield for the housing, even when it is provided, is not so formed that the shield for housing can be fastened by screws. In such cases, how to ground the shield for the slot portion becomes a problem. 
     In order to ground the shield for the slot portion by bringing the shield into electrical contact with a structure other than the shield for the housing, it is necessary that the function of the object structure with which the shield to be grounded is brought into electrical contact is not spoiled. 
     It is an object of the present invention to provide an electronic apparatus having a structure capable of grounding a shield for a slot portion reliably without using a screwing method. 
     To attain the above-mentioned object, according to the present invention, there is provided the electronic apparatus including a slot unit adapted to connect external machines thereto, a shield member provided with the slot unit, and a ground potential member, the shield member having at least one contacting portion adapted to establish contact with a ground potential member so as to obtain a grounding potential therefrom. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view showing an external appearance of a shield  801  fixed to a slot unit  301  according to an embodiment of the present invention; 
     FIG. 2 is a partial sectional view of a slot unit  301  and a shield  801  of an entertainment system according to an embodiment of the present invention; 
     FIG. 3 is a sectional view showing the general construction of the entertainment system according to an embodiment of the present invention; 
     FIG. 4 is a sectional view of the shield according to an embodiment of the present invention; 
     FIG. 5A is a top view of the shield according to an embodiment of the present invention; 
     FIG. 5B is a front view of the shield according to an embodiment of the present invention; 
     FIG. 5C is a bottom view of the shield according to an embodiment of the present invention; 
     FIG. 6 is a front view of a housing of the entertainment system according to an embodiment of the present invention, and a top view of an operating devices  220 ; 
     FIG. 7 illustrates an explanatory view of the shapes of three constituent members of the housing  100  of the entertainment system according to an embodiment of the present invention; 
     FIG. 8 is a perspective view showing the entertainment system according to an embodiment of the present invention with an upper portion of the housing  100  taken away; 
     FIG. 9 is a perspective view showing a rear surface of the housing  100  of the entertainment system according to an embodiment of the present invention; and 
     FIG. 10 is a front view showing an inner construction of the slot unit  301  of the entertainment system according to an embodiment of the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     An embodiment of the present invention will now be described with reference to the drawings. In the following embodiment, an entertainment system, being an electronic apparatus will be described. 
     A housing  100  of embodiment of the entertainment system includes three parts as shown in FIG.  7 . Namely, the housing  100  is formed of an upper housing member  110 , an intermediate chassis  140  and a lower housing member  170 . Both of the upper and lower housing members  110 ,  170  have a substantially flat, rectangular parallelopipedal shape. The upper housing member  110 , intermediate chassis  140  and lower housing member  170  are fixed to one another by bolts (not shown) and thereby integrated. 
     The intermediate chassis  140  is provided with a rear wall portion  141 , and a floor portion  142 . This floor portion  142  divides an inner space of the housing  100  into a storage space on the side of the upper housing member  110 , and a storage space on the side of the lower housing member  170 . The floor portion  142  is mounted with various kinds of machines housed in the upper housing member  110 . The machines mounted on the floor portion  142  are, for example, a disk unit  310 , a slot unit  301 , a power source unit  302 , and a switch inlet unit  304  as shown in FIG.  8 . The floor portion  142  is provided with a through hole  142   b  (refer to FIG.  7 ). Radiation fins  306  (refer to FIG. 8) set on the lower housing member  170  extend through the through hole  142   b  and project into the storage space on the side of the upper housing member  110 . The floor portion  142  is further provided with a nick  142   a , in which an exhaust fan  305  is provided. 
     The slot unit  301  is screwed on a projection provided on an upper surface of the floor portion  142  and thereby fixed to the floor portion  142 . A shield  801  is fitted to a rear surface of the slot unit  301 . The shield  801  is provided with spring members  811 ,  812 ,  813 ,  814  supported in a cantilevered manner at their respective lower ends as shown in FIG.  1 . The spring members  811 - 814  are bent in the doglegged shape at a free end portion of each thereof. The free end portions of the spring members  811 ,  812 ,  813 ,  814  are pressed against the radiation fins  306 , i.e., brought into electrical contact therewith. Thus, the shield  301  obtains a grounding potential from the radiation fins  306 . Since this structure is the most characteristic part of the embodiment, a detailed description thereof will be given later. 
     The disk unit  310  is a recording medium driving unit for carrying out the reproduction of a disk type recording medium, such as a CD and a DVD, and has a tray  315  which is capable of projecting and retracting and a unit body  316 . The tray is mounts thereon a disk type recording medium. The disk unit body  316  holds therein a reproducing unit that retracts the tray  315  and reproduces a disk, such as a CD and a DVD placed in the tray  315 . 
     The rear wall portion  141  of the intermediate chassis  140  is provided with a nick  143   a  as shown in FIG.  9 . The switch inlet unit  304  is exposed to the outside from this nick  143   a . The rear wall portion  141  is provided with an exhaust hole  143   b  at a position opposed to the exhaust fan  305 . A lower rear wall member  144  is provided with various kinds of communication terminals  521   a ,  521   b , a card inserting slot  521   c  and a slot operating switch  524  as shown in FIG.  9 . 
     The lower housing  170  is provided therein with a main board  381  having a CPU  380  mounted thereon as shown in FIG. 3. A metal pipe type heat sink  383  is fixed on an upper surface of the CPU  380  with an adhesive. The CPU  380  and the pipe type heat sink  383  are covered with a shield  384  made of a metal plate. The shield  384  is provided with an opening  385 , in which the radiation fins  306  are inserted and fixed to an upper surface of the pipe type heat sink  384 . The shield  384 , the pipe-type heat sink  383  and the radiation fins  306  electrically contact to each other, and have a equal grounding potential to each other. 
     The lower housing member  170  is provided with a vent hole  190  as shown in FIG. 6 which constitutes an intake port for the outside air, i.e. a flow of the air generated by the exhaust fan  305 . As shown in FIG. 2, the floor portion  142  at a lower section of the slot unit  301  is also provided with a vent hole  191 . The lower housing  170  is also provided with a connector unit  400  as shown in FIG. 6, for joining connectors thereto. 
     A front wall  114  of the upper housing member  110  is provided which four openings  132 ,  133  at a position corresponding to the slot unit  301  (FIG. 7) for forming parts receiving portions  320 ,  330 . The front wall  114  is also provided with an opening  131  for the disk unit  310 . The front wall  114  of the upper housing  110  is provided with a projected switch  341  for the disk unit  310 , and a reset switch  351  (FIG. 6) in addition to these parts. 
     Next, the construction of the slot unit  301  and its shield  801  will be described in detail. 
     As shown in FIGS. 1,  2  and  8 , the slot unit  301  has a unit body  1600  and a circuit board  1300 . The unit body  1600  is provided with two memory device receiving portions  320  and two operating device receiving portions  330 . The memory device receiving portions  320  are arranged laterally, and the operating device receiving portions  330  are arranged thereunder. The operating device receiving portions  330  are adapted to hold connectors  221  of the operating devices  220  of FIG.  6  and establish the electrical connection therewith. The memory device receiving portions  320  are adapted to hold card type external memories for storing information, such as the progress of the game played and establish the electrical connection therewith. 
     Specifically, each of the memory device receiving portions  320  is provided with an opening  1500  made in the unit body  1600 , three base seats  1511  formed in the opening  1500 , and terminals  1501  fixed to the base seats  1511  as shown in FIGS. 2 and 10. The terminals  1501  are connected to wiring on the circuit board  1300 . Each of the operating device receiving portions  330  is provided with an opening  1400 , three base seats  1411  projecting from the opening  1400 , and cylindrical terminals  1401  set in inner portions of the base seats  1411 . The opening  1400  is also provided at an upper portion thereof with three metal retainers  1403 , some of which serve also as electric terminals. The cylindrical terminals  1401  and metal retainers  1403  are connected to the wiring of the circuit board  1300 . 
     The shield  801  is provided on a rear surface of the slot unit  301  as shown in FIGS. 1 and 2. The shield works to prevent the electromagnetic waves occurring in the housing  100  from leaking to the outside, and the electrostatic noise occurring in the vicinity of a connector  221  of an operating device  220  from exerting influence upon the CPU  380  in the housing  100 . As shown in FIGS. 1,  2 ,  4 ,  5 A,  5 B and  5 C, the shield  801  is formed by bending a phosphor bronze plate to a three-sided angular shape, and has a top plate  503 , a front plate  504  and a bottom plate  505 . 
     As shown in FIGS. 1 and 5A, the top plate  503  is provided at both sides thereof with locking portions  501  which are engaged with upper portions of the circuit board  1300  as shown in FIG. 2, so as to fix the shield  801  to the slot unit  301 . The top plate  503  is also provided with projections  506  which are in pressure contact with a grounding wiring pad on the circuit board  1300 . Free ends of the projections  506  are sharpened, and capable of breaking through a flux layer and an oxide film of the grounding wiring pad and thereby contacting with the same pad with a low impedance. 
     The front plate  504  is provided with four slits  511 - 514  as shown in FIGS. 1 and 5B. Metal plate in the slits are cut and raised at a certain angle and cantilevered, whereby four spring members  811 - 814  are formed. Free end portions of the spring members  811 - 814  are bent in the doglegged shape. 
     The bottom plate  505  is formed like three teeth of a comb as shown in FIG.  5 C. Free end portions of the comb teeth are provided with non-slip projections  521 . 
     The top and bottom plates  503 ,  505  respectively contact with top and bottom surfaces respectively of the unit body  1600 . The front plate  504  is opposed to the circuit board  1300  via a clearance  522 . 
     The free end portions of the spring members  811 - 814  of the front plate  504  are pressed against end surfaces  307  of the radiation fins  306 , whereby the spring members electrically contact with the radiation fins. 
     The shield  801  obtains a grounding potential by pressing the spring members  811 - 814  against the radiation fins  306 . Since the projections  506  of the shield  801  are pressed against the grounding wiring pad on the circuit board  1300 , the radiation fins  306 , the shield  801  and the grounding wiring of the circuit board  1300  come to have a grounding potential respectively. This enables the shield  801  to function as an electromagnetic shield and an electrostatic shield. 
     The shield  801  in this embodiment serves the purpose by merely bringing the spring members  811 - 814  into contact with object members (the radiation fins  306  in this embodiment) of a grounding potential. Accordingly, it is unnecessary that the spring members be screwed on the object members for the purpose of obtaining a grounding potential. Thus, a grounding potential can be obtained by merely bringing the spring members into contact with the object members (the radiation fins  306 ), irrespective of the strength of the spring members and irrespective of whether the spring members are structurally screw-fixable or not. This enables a range of selection of object members for obtaining a grounding potential to expand. In this embodiment, the radiation fins  306  are selected as the object members which the spring members contact. Since the air is supplied from the front vent holes  190 ,  191  toward the exhaust fan  305 , the radiation fins  306  are disposed perpendicularly to the shield  801 . Therefore, end surfaces of a small area of the radiation fins  306  are opposed to the spring members  811 - 814 . The spring members cannot be screwed on the end surfaces of a small area of the radiation fins  306 . However, the spring members  811 - 814  in this mode of embodiment may have only to be brought into contact with the radiation fins  306 , so that a grounding potential can be obtained without any trouble from the radiation fins  306 . 
     A contact surface area between the spring members  811 - 814  and object members is smaller than that between screws and object members in the case of a screw-fixed structure. Therefore, the quantity of heat transmitted from the object members to the slot unit via the spring members  811 - 814  becomes small. Accordingly, even the members the temperature of which becomes high, such as the radiation fins  306  does not transmit such a large quantity of heat that exerts influence upon the slot unit  301  in the structure of the shield  801 . Moreover, since the spring members  811 - 814  are cut and raised from the front plate  504  at a certain angle, the clearance  523  is provided between the front plate  504  and heat sink  307 . A clearance  522  is also provided between the front plate  504  and circuit board  1300 , and the clearances  522 ,  523  communicate with on another via the slits  511 - 514  of the front plate  504 . Accordingly, a flow of the air from the front vent holes  190 ,  191  toward the exhaust fan  305  passes through the clearances  522 ,  523  and slits  511 - 514 . This enables the quantity of heat of the radiation fins  306  transmitted to the circuit board  1300  and unit body  1600  to be minimized. At the same time, the shield  801  does not prevent the radiation of heat of the radiation fins  306 . 
     Since the free end portions of the spring members  811 - 814  are bent in the shape of a hook, the angular portions thereof which contact the radiation fins  306  are round and smooth. Therefore, when the radiation fins  306  are put into the opening  142   b  of the floor portion  142 , to which the slot unit  301  is fixed, during the assembling work of the housing  100 , the insertion of the radiation fins  306  can be done smoothly as the end portions thereof are kept in contact with the spring members  811 - 814 . Since the radiation fins  306  may have only to be inserted in this manner into the opening  142   b , and do not require to be screw-fixed, a screw-fixing operation for attaining the electrical contact of parts becomes unnecessary, and the assembling of the housing can be done simply. Owing to the insertion of the radiation fins  306 , the spring members  811 - 814  receive a force by which the shield  801  is urged toward the circuit board  1300 . Consequently, the projections  506  of the shield  801  are pressed against the grounding wiring pad of the circuit board  1300 , and the free ends of the projections  506  break through the flux layer and the oxide layer on a surface portion of the grounding wiring pad to be connected to the grounding wiring pad with a low impedance. 
     The spring members  811 - 814  of the shield  801  can be designed so that the intervals thereof are at a desired level in accordance with a wavelength of the electromagnetic waves which are desired to be effectively screened. Accordingly, the number of the spring members  811 - 814  is not limited to four. The intervals of the spring members can be reduced by increasing the number of the spring members, and increased by reducing the number thereof. 
     When there is a scatter of the electric potential of the object members (end surfaces of the radiation fins  306 ) which the spring members contact, a spring member contacting an object member of a non-desired electric potential can be removed by breaking off the same, or such a spring member can be left not cut and raised from the first, so as to bring the spring members into contact with only the portions of a desired electric potential. In this case, a spring member which is not to be brought into contact with an object member can be decided by examining the distribution of electric potential of the radiation fins in each apparatus. Therefore, the spring members can be brought into contact with the portions of a desired electric potential reliably in each apparatus. 
     When the user plays a game with the entertainment system according to the embodiment, an external display is joined to the connecting portion  521  of the housing  100 , and the connector  221  of the operating device  220  is joined to the receiving portion  330 . The power source of the switch inlet unit  304  is then turned on, and an optical disk is loaded into the tray  315  of the disk unit  311 . Consequently, the CPU  380  in the housing  100 -receives a game program and image information etc., which are recorded in the optical disk from the disk unit  311 , and shows an image on the external display. The CPU  380  communicates with the operating device  220 , and receives the details of the user&#39;s operation namely how the switches  219 ,  218 ,  224 - 229  were operated by the user. The CPU  380  executes the game program in accordance with the details of the user&#39;s operation received, to vary the image displayed. When a card type memory device is held in the receiving portion  320 , the CPU  380  communicates with the card type memory device to read the game information stored therein, and reflect the information upon the execution of the game program. In accordance with the game program, the game information is stored in the card type memory device. 
     Due to such operations of the CPU  380 , heat generates therein, which is transmitted to the pipe type heat sink  383  and then to the radiation fins  306 . While the air taken in from the vent holes  190 ,  191  flows toward the exhaust fan  305 , it passes spaces among the radiation fins  306  to remove the heat thereof. Owing to this operation, the heat of the CPU  380  is discharged from the exhaust fan  305  to the outside. The shield  801  contacts the radiation fins  306  but the contacting surface area therebetween is small as mentioned above. Moreover, the air flows through the clearance  523  between the shield  801  and radiation fins  306 , so that the heat of the radiation fins  306  is not substantially transmitted to the slot unit  301 . 
     Since the spring members  811 - 814  of the shield  801  contact the radiation fins  306  as described above, the shield  801  obtains a grounding potential from the radiation fins  306 , and works as an electromagnetic shield and an electrostatic shield. This prevents the electromagnetic waves in an inner portion of the housing  100  from leaking from the slot unit  301  to the outside. It is also possible to prevent the electrostatic noise occurring in the vicinity of the connector  221  from exerting an ill influence upon the CPU  380 . The electric potential of the grounding wiring on the electric circuit  1300  also becomes equal to that of the shield  801 . 
     In the above-described mode of embodiment, the spring members  811 - 814  of the shield  801  are projected rearward, and brought into contact with the radiation fins  306  to obtain a grounding potential. When the object members from which a grounding potential is obtained are positioned on an upper or side surfaces of the slot unit  301 , the spring members  811 - 814  can be cut, raised and projected toward the object members. 
     In this embodiment, parts of the metal plate forming the shield  801  are cut and raised to form the spring members  811 - 814 . It is also possible to prepare spring-like metal members separately from the metal plate of the shield  801 , and fix these metal members to the metal plate of the shield  801 . 
     The free end portions of the spring members  811 - 814  may not necessarily bent in the shape of a hook. The free end portions can be sharpened as those of the projections  506  so that the spring members can break through the oxide films in the surface portions of the object members (radiation fins  306 ) and thereby contact the same. 
     Furthermore, in this embodiment, the CPU  380  is disposed in a position in which the quantity of the electromagnetic waves leaking from the side surfaces of the slot unit  301  is small. Accordingly, the shield  801  does not cover the side surfaces of the slot unit  301 . The shield can, of course, be formed so as to cover the side surfaces as well of the slot unit. 
     The present invention can provide an electronic apparatus of a structure capable of grounding the shield of the slot unit reliably without using a screwing method.