BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates generally to a connection device disposed on a mobile phone, PHS (Personal Handyphone System) and other mobile information terminals for connection with external devices such as peripherals, and, more particularly, to antistatic measures for a connection device and electronic equipment having the connection device.  
           [0003]    2. Description of the Related Art  
           [0004]    Mobile phone is provided with connection devices such as charge terminals and USB (Universal Serial Bus) connection terminals. With such connection devices, charge terminals are connected to a charger for charging the built-in secondary battery, whereas USB connection terminals and others are connected to external equipment such as personal computer for exchanging information. Connection terminals provided on a mobile phone are exposed outside the case to facilitate connection with the charger or external equipment and therefore subjected to an electrostatically charged environment such as human body.  
           [0005]    Japanese Utility Model Registration No. 3078521 and Japanese Patent Application Laid-Open Publication No. 2000-347790 are among prior patent documents in relation to these connection devices and antistatic measures thereof.  
           [0006]    Japanese Utility Model Registration No. 3078521 discloses, as a USB connector with upgraded grounding effect, one in which the connector&#39;s grounding effect has been upgraded by establishing electrical continuity between the metal case and the electrical conduction means through connection. Meanwhile, Japanese Patent Application Laid-Open Publication No. 2000-347790 relates to a keyboard apparatus and discloses, as a USB-compatible keyboard apparatus preventing defects caused by electrostatic noise such as malfunction and faulty operation, a construction in which a shield plate is provided covering the underside of the control circuit board and the shield plate is electrically connected to the USB connector&#39;s frame ground portion and to the shield wire of a cable connected to the PC main body.  
           [0007]    Incidentally, electrostatic discharge—resulting from static electricity from a human body, etc. acting on the USB and other connection terminals exposed on a mobile phone —leads to a high voltage being applied to the circuit board side of the mobile phone, possibly damaging the circuitry in the circuit board side or resulting in malfunction.  
           [0008]    While the aforementioned patent documents present the problem in respect of electrostatic countermeasures, they are not designed to ensure electrostatic damage prevention or lightning protection for connection devices used for external connection.  
         SUMMARY OF THE INVENTION  
         [0009]    It is an object of the present invention to prevent electrostatic damage to the connection device.  
           [0010]    It is another object of the present invention to prevent electrostatic damage to electronic equipment provided with the connection device.  
           [0011]    To achieve the above objects, the connection device of the present invention comprises conductive terminals and lightning conductor portions  34  provided adjacent to and insulated from the conductive terminals and maintained at the grounding potential through connection to a grounded conductor.  
           [0012]    If the connection device is exposed to an electrostatically charged environment such as human body, such a configuration allows static electricity to jump to the lightning conductor portions on the grounding potential side because the lightning conductor portions are provided adjacent to and insulated from the conductive terminals for external connection and maintained at the grounding potential through connection to a grounded conductor. That is, static electricity of the human body, etc. flows into the grounded conductor side through the lightning conductor portions, avoiding induction of static electricity into the conductive terminal side and protecting the circuit board and its mounted components from high voltage caused by static electricity.  
           [0013]    To achieve the above objects, the lightning conductor portions may be configured such that their conductor surface is positioned higher than the terminal surfaces of the conductive terminals. Such a configuration brings each of the lightning conductor portions closer to the static electricity source such as human body than the conductive terminals, inducing static electricity into the lightning conductor portions and improving lightning protection effect for the conductive terminals.  
           [0014]    To achieve the above objects, the lightning conductor portions may be configured such that their conductor surface is smaller in area than the terminal surfaces of the conductive terminals. It suffices even in such a configuration to provide the lightning conductor portions, maintained at the grounding potential, adjacent to the conductive terminals, providing lightning protection effect irrespective of the area thereof.  
           [0015]    To achieve the above objects, each of the lightning conductor portions may be provided with one, two or more protrusions on the conductor surface. Such a configuration allows static electricity to readily jump to the protrusions, improving lightning protection effect for the conductive terminals.  
           [0016]    To achieve the above objects, the electronic equipment of the present invention is provided with the aforementioned connection device. Such a configuration allows static electricity to jump to the lightning conductor portions, protecting the conductive terminals for external connection and preventing electrostatic damage to and malfunction of the electronic equipment.  
           [0017]    Features and advantages of the present invention are listed below.  
           [0018]    (1) According to the connection device of the present invention, it is possible to generate electrostatic discharge in the lightning conductor portions adjacent to the conductive terminals, thus avoiding electrostatic discharge to the conductive terminal side and protecting the circuit board and its electronic components connected to the conductive terminals from electrostatic damage.  
           [0019]    (2) In the connection device of the present invention, positioning its conductor surface higher than the terminal surfaces of the conductive terminals facilitates electrostatic discharge on the lightning conductor portions, thus providing improved lightning protection effect.  
           [0020]    (3) In the connection device of the present invention, reducing its conductor surface to be smaller in area than the terminal surfaces of the conductive terminals allows reducing the area occupied by the lightning conductor portions in the connection device while providing lightning protection effect.  
           [0021]    (4) In the connection device of the present invention, providing one, two or more protrusions on the conductor surface of the lightning conductor portions allows static electricity to readily jump to the protrusions, improving lightning protection effect for the conductive terminals.  
           [0022]    (5) According to the electronic equipment of the present invention, the connection device provided in the electronic equipment allows static electricity to jump to the lightning conductor portions, protecting the conductive terminals for external connection and preventing electrostatic damage to and malfunction of various electronic equipment such as mobile phone. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0023]    Other objects, features and advantages of the present invention will become more apparent from the accompanying drawings and embodiments.  
         [0024]    [0024]FIG. 1 is a perspective view of a mobile phone according to an embodiment of the present invention when it is open;  
         [0025]    [0025]FIG. 2 is a rear side view of a control portion in which the connection device is provided;  
         [0026]    [0026]FIG. 3 is a view showing the appearance of the connection device provided in the control unit;  
         [0027]    [0027]FIG. 4 is an exploded perspective view showing the connection device by disassembling the control unit;  
         [0028]    [0028]FIG. 5 is a sectional view of the connection device taken on line V-V of FIG. 4;  
         [0029]    [0029]FIG. 6 is a sectional view of the connection device taken on line VI-VI of FIG. 5;  
         [0030]    [0030]FIG. 7 is a view showing electrostatic discharge; and  
         [0031]    [0031]FIG. 8 is a view showing external connection of the mobile phone. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0032]    An embodiment of the connection device and electronic equipment of the present invention will be described with reference to FIGS.  1  to  3 . FIG. 1 is a perspective view of a mobile phone according to the embodiment when it is open, FIG. 2 is a rear side view of a control unit of the mobile phone, and FIG. 3 is a view showing a connection unit of the control unit.  
         [0033]    Having a fold-up structure, the mobile phone  2  is configured by a control unit  4  and a display unit  6  that are foldable by a hinge portion  8 , with a plurality of key buttons  10  including character keys provided in the control unit  4  and an LCD display  12  provided in the display unit  6 . A case  14  of the control unit  4  consists of a front case  16  and a rear case  18 , and a molded body of synthetic resin is, for example, employed for the front and rear cases  16  and  18 .  
         [0034]    A connection device  20  according to the embodiment of the present invention is provided at the edge portion of the control unit  4 , and a connector connection portion  22  is provided between charge terminals  24  and  26  in the connection device  20 , with the connector connection portion  22  and the charge terminals  24  and  26  being exposed from a window portion  28  of the case  14 .  
         [0035]    The connection device  20  also has, as conductive terminals for external connection, USB terminals  30 A,  30 B,  32 A and  32 B arranged with spacings, with a lightning conductor portion  34  constituting a lightning arrester provided between the USB terminals  30 A and  30 B and another between the USB terminals  32 A and  32 B. On the rear case  18 , window portions  36  and  38  are formed respectively in association with the USB terminals  30 A and  30 B and the lightning conductor portion  34  and the USB terminals  32 A and  32 B and the lightning conductor portion  34 , with the USB terminals  30 A and  30 B and the lightning conductor portion  34  exposed on the window portion  36  and the USB terminals  32 A and  32 B and the lightning conductor portion  34  exposed on the window portion  38 . Each of the window portions  36  and  38  is formed at the boundary portion between the rear surface portion and the end surface portion of the rear case  18 , with the USB terminals  30 A,  30 B,  32 A and  32 B provided inside the window portions  36  and  38 . The conductor surface of the top portion of each of the lightning conductor portions  34  projects outward more than the terminal surfaces of the USB terminals  30 A,  30 B,  32 A and  32 B and at the same time is located more backward on the inner surface side of the window portions  36  and  38  than the outer surface portion of the rear case  18 . A recessed portion  40  formed within the spacing between the window portions  36  and  38  is used to lock the connector cap not shown to the case  14 .  
         [0036]    Next, the connection device  20  of the mobile phone  2  will be described with reference to FIGS.  4  to  6 . FIG. 4 is a perspective view showing the connection device  20  extracted after disassembling the case  14 , and FIG. 5 is a sectional view of the connection device taken on line V-V of FIG. 4.  
         [0037]    The connection device  20 , installed on a circuit board  42  incorporated in the case  14 , is provided with an enclosure portion  44  formed with an insulating material such as synthetic resin. The enclosure portion  44  is provided with a protruding portion  46  that is inserted into the window portion  28  of the case  14  and also with protruding portions  48  and  50  that are inserted into the window portions  36  and  38  at its upper portion. A connector connection portion  22  is installed on the protruding portion  46 , with the charge terminals  24  and  26  provided on each side of the connector connection portion  22 . The flat terminal surfaces of the charge terminals  24  and  26  are provided within rectangular window portions  52  and  54  formed on the protruding portion  46 .  
         [0038]    On the protruding portions  48  and  50 , there are formed opening portions  56  and  58  respectively in association with the USB terminals  30 A and  30 B, and there are formed opening portions  60  and  62  respectively in association with the USB terminals  32 A and  32 B. The opening portions  56 ,  58 ,  60  and  62  are open extending from the upper surface sides of the protruding portions  48  and  50  to the end surface side of the case  14 , with a vertical wall portion  64  formed between the opening portions  56  and  58  for partitioning the opening portions  56  and  58  from each other and a vertical wall portion  66  formed between the opening portions  60  and  62  for partitioning the opening portions  60  and  62  from each other, and with the top portions of the vertical wall portions  64  and  66  curved on the end surface side of the case  14 . The terminal surfaces of the USB terminals  30 A,  30 B,  32 A and  32 B are arranged extending from the upper surface side to the side surface side of the case  14  and in a curved manner in association with the opening shapes of the opening portions  56 ,  58 ,  60  and  62 . The USB terminals  30 A,  30 B,  32 A and  32 B are connected to circuit conductors provided on the circuit board  42 .  
         [0039]    The lightning conductor portions  34  are individually supported by the vertical wall portions  64  and  66 , with the conductor surfaces at the top portions of the lightning conductor portions  34  exposed at the top portions of the vertical wall portions  64  and  66 . As shown in FIG. 5, therefore, a height h 1  of the conductor surfaces of the lightning conductor portions  34  relative to the circuit board  42  is higher than a height h 2  of the terminal surfaces of the USB terminals  30 A,  30 B,  32 A and  32 B and exposed on the opening surface sides of the window portions  36  and  38 . For this reason, the lightning conductor portions  34  are located closer to the static electricity source such as human body than the terminal surfaces of the USB terminals  30 A,  30 B,  32 A and  32 B.  
         [0040]    Next, the shape of the lightning conductor portions  34  will be described with reference to FIG. 6. FIG. 6 is a sectional view of the connection device  20  taken on line VI-VI of FIG. 5 by cutting through the connection device  20  at the vertical wall portion  66 .  
         [0041]    The enclosure portion  44  at which the lightning conductor portion  34  is grounded is formed with an insulator such as insulating synthetic resin and provided with a fitting protruding portion  68  at the bottom portion. As a result of fitting of the fitting protruding portion  68  into a fitting hole  70  of the circuit board  42 , the enclosure portion  44  of the connection device  20  is positioned on and firmly secured to the circuit board  42 .  
         [0042]    The lightning conductor portions  34 , formed with a conductor plate such as copper or brass plate, is provided with an exposed portion  72  that is supported by the vertical wall portion  66  of the enclosure portion  44  and whose conductor surface is exposed, an upright portion  74  that penetrates the enclosure portion  44  and a connection portion  76  that sticks out on the lower surface side of the enclosure portion  44  for connection with the circuit board  42 . In the exposed portion  72 , there are formed a projecting portion  78  that is exposed in association with the shape of the vertical wall portion  66  and a projecting portion  80  that is exposed in association with the front side of the vertical wall portion  66 . At the top portion of the exposed portion  72 , there are formed protruding portions  82  and  84  respectively at the rear edge and middle portions. The upright portion  74  is formed narrower than the exposed portion  72 , whereas the connection portion  76  is formed thinner than the upright portion  74 . Thus, the exposed portion  72  of the lightning conductor portion  34  spans from the rear portion to the front portion via the top portion, securing a wide conductor surface and facilitating or upgrading, thanks to the protruding portions  82  and  84 , static electricity jumping to the exposed portion  72 .  
         [0043]    The lightning conductor portion  34  is supported by the enclosure portion  44  as a result of the upright portion  74  penetrating through the vertical wall portion  66  that is an insulator. The connection portion  76  of the lightning conductor portion  34  penetrates to a penetration hole  86  of the circuit board  42 , with a frame ground  88 , a grounded conductor, electrically connected via a solder  90  to the connection portion  76  sticking out on the rear side of the circuit board  42 . Thus, the lightning conductor portion  34  is coated on the side surface portion with the vertical wall portion  66 , an insulator, providing insulation from the adjacent USB terminals  32 A and  32 B and maintaining the portion  34  at the same potential as the frame ground  88  of the circuit board  42  through connection to the frame ground  88  via the connection portion  76 . The same configuration is applied to the lightning conductor portion  34  on the side of the vertical wall portion  64 .  
         [0044]    According to the configuration, if the mobile phone  2  is placed near the static electricity source such as human body, and for example, if part of the electrostatically charged human body is brought close to the USB terminals  32 A and  32 B, static electricity jumps to the exposed portions  72  of the lightning conductor portions  34  because the lightning conductor portions  34  provided near the USB terminals  32 A and  32 B are maintained at the grounding potential, thus causing static electricity, i.e., charge to flow into the frame ground  88  of the circuit board  42  via the upright portion  74  and the connection portion  76 . In FIG. 7, 92 indicates electrostatic discharge. In this case, the conductor surface formed by the exposed portion  72  of the lightning conductor portion  34  is more elevated and larger in area than the USB terminals  32 A and  32 B, causing electrostatic discharge to jump to the side of the lightning conductor portion  34 , allowing the lightning conductor portion  34  to form a lightning protection barrier on the side of the USB terminals  32 A and  32 B and eventually avoiding electrostatic discharge to the USB terminals  32 A and  32 B. Such a lightning protection effect ensures avoiding electrostatic discharge similarly on the side of the USB terminals  30 A and  30 B thanks to the lightning conductor portion  34 . This protects the circuit conductors and electronic components of the circuit board  42  connected to the USB terminals  30 A,  30 B,  32 A and  32 B from electrostatic discharge, preventing electrostatic damage to the circuit board  42  and internal circuitry of the mobile phone  2  and their malfunction.  
         [0045]    The lightning conductor portion  34  is provided adjacent to the USB terminals  30 A and  30 B or  32 A and  32 B, and in the case of the embodiment, provided between the USB terminals  30 A and  30 B or  32 A and  32 B, forming a grounding barrier on the USB terminals  30 A and  30 B or  32 A and  32 B and providing, through an extremely simple structure, lightning protection capability.  
         [0046]    In the case of the present mobile phone  2 , the built-in secondary battery is charged by installing the mobile phone  2  to a cradle  94  for charging and external connection, connecting an AC/DC converter  100  to the charge terminals  24  and  26  of the connection device  20  via connection terminals  96  and  98  of the cradle  94  and applying DC output obtained by rectifying AC current from an AC power supply  102 . On the other hand, peripheral equipment such as personal computer (not shown) is connected to the USB terminals  30 A,  30 B,  32 A and  32 B of the connection device  20  via a USB cable  108  connected to connection terminals  104  and  106  of the cradle  94 , thus enabling information exchange between the mobile phone  2  and external equipment. In this case, the lightning conductor portion  34  is grounded, making it possible to avoid electrostatic discharge to the USB terminals  30 A,  30 B,  32 A and  32 B during use.  
         [0047]    Next, modifications and other technical extensions of the embodiment of the aforementioned connection device and electronic equipment will be listed below.  
         [0048]    (1) While the above embodiment was described with reference to a mobile phone, the connection device and electronic equipment of the present invention include mobile phone, PHS, PDA (Personal Digital Assistant), PC (Personal Computer), handheld PC (handheld Personal Computer) and other mobile information terminals, and the present invention is applicable to connection devices and electronic equipment including digital camera having conductive terminals such as USB terminals and are not limited to the mobile phone of the embodiment.  
         [0049]    (2) While the above embodiment was described with reference to USB terminals, the present invention is applicable to connection devices having conductive terminals other than USB terminals and is not limited to USB terminals.  
         [0050]    (3) While the above embodiment was described with reference to the case in which the case  14  is a joined body of the front and rear cases  16  and  18 , the case may be configured by a single case with a cover portion.  
         [0051]    While a description was given, as described above, of the most preferred embodiments of the present invention, the present invention is not limited thereto and may, needless to say, be modified or changed variously by those skilled in the art based on the concept of the present invention described in the appended claims and disclosed in the detailed description of the present invention, and, of course, it includes such a modification or change.  
         [0052]    The entire disclosure of Japanese Patent Application No. 2003-169820 including specification, claims, drawings and summary are incorporated herein by reference.
The present invention relates to a connection device of electronic equipment and provides a connection device preventing electrostatic damage and electronic equipment provided with the connection device. The connection device comprises conductive terminals and lightning conductor portions disposed adjacent to and insulated from the conductive terminals, the lightning conductor portions being kept at the grounding potential through connection to a grounded conductor, thus causing static electricity discharge in the lightning conductor portions and avoiding discharge toward the conductive terminals.