Patent Publication Number: US-2010112832-A1

Title: Connector

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to connectors. 
     2. Description of the Related Art 
     Recent developments in communications technologies have aroused a demand for connectors that enable transmission of signals at ultra-high speed. This type of connector has multiple signal contacts and multiple ground contacts, and shields the signal contacts by surrounding them with the corresponding ground contacts, thereby preventing noise from entering the signal contacts. (See, for example, Japanese Laid-Open Patent Application No. 2-223172.) 
     This type of connector is mounted on a board. Surface mounting, which makes it possible to reduce size, increase density, and lower cost, has become a mainstream method of mounting electronic components on boards. This has also promoted surface mounting of connectors on boards. For example, the contacts of a connector and corresponding interconnects (lands) of a wiring board are temporarily joined with solder cream and thereafter subjected to a reflow process so as to be soldered. 
     SUMMARY OF THE INVENTION 
     According to an aspect of the present invention, a connector includes a housing to be fixed to a board; and a contact provided in the housing, the contact being configured to be connected to a plug to be attached to the housing, the contact including a first contact part including a body part, a first terminal part provided at a first end of the body part and configured to connect to the plug, and a first connection part provided at a second end of the body part; one or more second contact parts each including a second terminal part at a first end thereof and a second connection part at a second end thereof, the second terminal part being configured to connect to an electrode provided on the board; and one or more third contact parts each including an elastically deformable elastic part having a first end thereof connected to the first contact part and a second end thereof connected to the second contact part, the third contact part being configured to hold the first connection part and the second connection part so that the first connection part and the second connection part face each other across a gap, wherein the second terminal part is configured to be brought into press contact with the electrode by an elastic force to be generated in the third contact part in response to fixation of the housing to the board, and the third contact part is configured to elastically deform in response to at least one of attachment of the plug to the housing and the fixation of the housing to the board, so as to cause the first connection part and the second connection part to come into contact and be electrically connected. 
     According to an aspect of the present invention, a connector includes a housing to be fixed to a board; and one or more contacts provided in the housing, the contacts being configured to be connected to corresponding plugs to be attached to the housing, wherein the contacts include a ground contact, the ground contact including a substantially cylindrical ground contact body part; a first terminal part provided at a first end of the ground contact body part to be connected to a corresponding one of the plugs; and a plurality of second terminal parts extending from a second end of the ground contact body part to be connected to the board, the second terminal parts each including a first member extending from the ground contact main body part toward the board; and a second member having a curved shape so as to have an end part thereof facing the first member across a gap, the second member being configured to be deformed to cause the end part thereof to come into contact with the first member and to be brought into press contact with an electrode of the board by an elastic force generated in the second member by fixation of the housing to the board. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other objects, features and advantages of the present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings, in which: 
         FIG. 1  is an exploded perspective view of a connector according to a first embodiment of the present invention; 
         FIG. 2  is a perspective view of the connector to which a plug is attached according to the first embodiment of the present invention; 
         FIG. 3  is a bottom-side perspective view of the connector according to the first embodiment of the present invention; 
         FIG. 4  is a bottom-side perspective view of the connector with a bottom plate according to the first embodiment of the present invention; 
         FIG. 5  is a cross-sectional view of part of the connector according to the first embodiment of the present invention; 
         FIG. 6  is a perspective view of a signal contact according to the first embodiment of the present invention; 
         FIGS. 7A and 7B  are enlarged views of a third signal contact part and its neighborhood of the signal contact according to the first embodiment of the present invention; 
         FIG. 8  is a perspective view of a ground contact according to the first embodiment of the present invention; 
         FIG. 9  is an enlarged perspective view of third ground contact parts and their neighborhood of the ground contact according to the first embodiment of the present invention; 
         FIG. 10  is an enlarged view of a pair of a signal terminal and a ground terminal formed on a board according to the first embodiment of the present invention; 
         FIG. 11  is an enlarged view of signal terminals and ground terminals formed on the board according to the first embodiment of the present invention; 
         FIG. 12  is a top-side perspective view of the connector according to the first embodiment of the present invention; 
         FIG. 13  is an enlarged perspective view of part of the bottom plate of a connector housing according to the first embodiment of the present invention; 
         FIG. 14  is an exploded perspective view of a connector according to a second embodiment of the present invention; 
         FIGS. 15A and 15B  are a top-side perspective view and a bottom-side perspective view, respectively, of the connector, illustrating its exterior, according to the second embodiment of the present invention; 
         FIG. 16  is a perspective view of a plug according to the second embodiment of the present invention; 
         FIG. 17  is a perspective view of a signal contact, illustrating its exterior, according to the second embodiment of the present invention; 
         FIG. 18  is a perspective view of a ground contact, illustrating its exterior, according to the second embodiment of the present invention; 
         FIG. 19  is a diagram illustrating how the plug is attached to the connector according to the second embodiment of the present invention; 
         FIG. 20  is an enlarged perspective view of part of the ground contact according to the second embodiment of the present invention; and 
         FIG. 21  is an enlarged view of part of the bottom surface of the connector according to the second embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As described above, the contacts of the conventional connector are soldered to the board. Therefore, if the board warps to generate a gap between the contacts and the interconnects of the board, this prevents the contacts from being soldered properly to the board, thus causing the problem of reduction in the reliability of the connection between the connector and the board. 
     Further, according to the conventional configuration where the contacts and the board are soldered, removal of the connector from the board for repairing is accompanied by heating soldered points to melt solder. Therefore, there is also the problem of poor repairability. 
     A description is given below, with reference to the accompanying drawings, of embodiments of the present invention. 
     First Embodiment 
       FIG. 1  and  FIG. 2  are diagrams illustrating a connector  10  according to a first embodiment of the present invention.  FIG. 1  is an exploded perspective view of the connector  10 .  FIG. 2  is a perspective view of the connector  10 , illustrating its exterior. 
     The connector  10  includes a connector housing  20 , signal contacts  30 , and ground contacts  40 . The connector  10  is to be surface-mounted on a board  60  ( FIG. 5 ), and electrically connects a plug  50  inserted into the connector  10  and the board  60 . 
     The connector housing  20  is formed by molding thermoplastic resin such as LCP (liquid crystal polymer). The connector housing  20  includes a body part  21 . Multiple attachment holes  22  to which the signal contacts  30  and the ground contacts  40  are attached are formed through the body part  21 . Further, the connector housing  20  includes flange parts  23  on four peripheral sides. Each of the flange parts  23  has an insertion hole  24  into which a fixation screw (not graphically illustrated) is to be inserted that is used at the time of mounting the connector  10  on the board  60 . 
       FIG. 3  is a bottom-side perspective view of the connector  10 .  FIG. 4  is a bottom-side perspective view of the connector  10  without a bottom plate  29 . 
     Referring to  FIG. 4 , a step part  25  for attaching the bottom plate  29  (described below) is formed on the bottom surface of the connector housing  20 . Further, positioning projections  26  are provided and screw holes  27  are formed at predetermined positions of the step part  25 . 
     Here, a brief description is given of the plug  50 . Referring to  FIG. 1  and  FIG. 5 , the plug  50  includes a plug pin  51 , a ground member  52 , and an insulator  53 . For example, the plug pin  51  is press-fit into a small hole formed through the insulator  53 , and this insulator  53  is press-fit into the tubular ground member  52 . 
     This plug  50  is provided to a cable  54  for high-speed transmission ( FIG. 2 ). The high-speed transmission cable  54 , which is a coaxial cable, includes copper core wire serving as a signal line, a resin insulator, a shield line formed of braided wire, and a resin protection film, which are coaxially stacked in layers successively from the center position. The core wire of the cable  54  is connected to the plug pin  51 , and the shield line of the cable  54  is connected to the ground member  52 . 
     As illustrated in  FIG. 2  and  FIG. 5 , this plug  50  is inserted into and attached to the corresponding attachment hole  22  to be connected to the connector  10 .  FIG. 5  illustrates a state where the plug  50  is inserted into and attached to the left attachment hole  22  and no plug is attached to the right attachment hole  22  of the connector  10 . 
     As illustrated in  FIG. 5 , with the plug  50  being attached to the connector  10  (which state is hereinafter referred to as “attached state”), the plug pin  51  of the plug  50  is connected to the corresponding signal contact  30  of the connector  10 . Further, in the attached state, the ground member  52  of the plug  50  is connected to the corresponding ground contact  40  of the connector  10 . 
     Next, a description is given of the signal contact  30 . The signal contact  30  is connected to the plug pin  51  when the plug  50  is connected to the connector  10 . The plug pin  51  is connected to the signal line (core wire) of the cable  54 , so that a signal transmitted through the cable  54  is transmitted to the signal contact  30  through the plug pin  51 . 
       FIG. 6  is an enlarged perspective view of the signal contact  30 . The signal contact  30 , which is formed of a contact material such as phosphor bronze, includes a first signal contact part  31 , a second signal contact part  32 , and a third signal contact part  33 , which are formed into a unitary structure. The first signal contact part  31  may be a first contact part. The second signal contact part  32  may be a second contact part. The third signal contact part  33  may be a third contact part. 
     The first signal contact part  31  includes a signal contact body part  31 A, a plug signal terminal part  31 B, and a first signal connection part  31 C ( FIGS. 7A and 7B ). The plug signal terminal part  31 B may be a first terminal part. The first signal connection part  31 C may be a first connection part. The signal contact body part  31 A is press-fit into a contact holding part  21   a  ( FIG. 5 ) formed inside the corresponding attachment hole  22  provided in the connector housing  20 . The signal contact body part  31 A is press-fit into the contact holding part  21   a  so that the signal contact  30  is held by the connector housing  20 . 
     Further, the first signal contact part  31  has the plug signal terminal part  31 B provided at the upper end of the signal contact body part  31 A. The plug signal terminal part  31 B is connected to the plug pin  51  when the plug  50  is attached to the connector  10 . Further, the first signal contact part  31  has the first signal connection part  31 C provided at the lower end of the signal contact body part  31 A. 
     Throughout the specification, the term “upper” refers to the side from which the plug  50  is inserted (the Z 1  side in the drawings), and the term “lower” refers to the side opposite to the “upper” side (the Z 2  side in the drawings). 
     Referring to  FIGS. 7A and 7B  as well as  FIG. 6 , the second signal contact part  32  has a substantially linear shape. The second signal contact part  32  has a board signal terminal part  32 A at its lower end and has a second signal connection part  32 B at its upper end. The board signal terminal part  32 A may be a second terminal part. The second signal connection part  32 B may be a second connection part. 
     The board signal terminal part  32 A is connected to a corresponding one of signal terminals  61  formed on the substrate  60  with the connector  10  mounted on the substrate  60 . In this case, the board signal terminal part  32 A is not soldered but is in press contact with the corresponding signal terminal  61  to be electrically connected to the signal terminal  61  (of which a description is given below). Further, the board signal terminal part  32 A is bent so as to establish good connection to the signal terminal  61 . 
     On the other hand, referring to  FIG. 7A , the second signal connection part  32 B is configured to face the first signal connection part  31 C of the first signal contact part  31  across a gap or space between them with the plug  50  being not attached to the connector  10 . As described below, when the plug  50  is attached to the connector  10  or the connector  10  is mounted on the board  60 , the first signal connection part  31 C and the second signal connection part  32 B are electrically connected. 
     The third signal contact part  33  includes an elastic deformation part  33 A, an upper end part  33 B, and a lower end part  33 C. The elastic deformation part  33 A is elastically deformable. The upper end part  33 B and the first signal contact part  31  are connected in a unitary structure. The lower end part  33 C and the second signal contact part  32  are connected in a unitary structure. The signal contact  30  is formed by working a plate material serving as a base material by press blanking and further bending the plate material into a predetermined shape as illustrated. The elastic deformation part  33 A is formed by bending a corresponding U-shaped portion of the blanked-out plate material so as to be substantially U-shaped when viewed along the Z-axis (the Z 1  and the Z 2  direction) as well. 
     The third signal contact part  33  is elastically deformable as described above so as to allow the second signal contact part  32  to be displaceable in the Z 1  and the Z 2  direction relative to the first signal contact part  31  in  FIG. 6 . Further, the elastic deformation of the third signal contact part  33  generates an elastic restoring force in the third signal contact part  33 . 
     Upward displacement of the second signal contact part  32  (in the Z 1  direction) relative to the first signal contact part  31  generates an elastic force (elastic restoring force) to urge the second signal contact part  32  in the downward (Z 2 ) direction in the elastic deformation part  33 A. This elastic force serves as a force to bring the board signal terminal part  32 A into press contact with the board  60  when the connector  10  is mounted on the board  60 . 
     On the other hand, as shown enlarged in  FIGS. 7A and 7B , the first signal connection part  31 C of the first signal contact part  31  extends in the Z 2  direction from the position of connection of the upper end part  33 B of the third signal contact part  33  and the first signal contact part  31 . Further, with no external force applied, the third signal contact part  33  keeps the first signal connection part  31 C and the second signal connection part  32 B of the second signal contact part  32  facing each other across a narrow gap (or in proximity to each other). 
     Therefore, if the plug  50  is attached to the connector  10  so as to cause the plug pin  51  to come into contact with the signal contact  30  to press and displace the plug signal terminal part  31 B in the direction indicated by arrow A (or the clockwise direction) in  FIG. 7B , the first signal contact part  31  is rotationally displaced, centered on the position of connection with the upper end part  33 B of the third signal contact part  33 . Therefore, the first signal connection part  31 C is displaced in the direction indicated by arrow A in  FIG. 7B  with the elastic deformation of the third signal contact part  33 . As a result, the first signal connection part  31 C comes into contact with the second signal connection part  32 B so as to establish electrical connection between them. 
     When the first signal connection part  31 C and the second signal connection part  32 B are thus connected electrically, there are two possible signal transmission routes formed between the first signal contact part  31  and the second signal contact part  32 : one is through the third signal contact part  33  and the other is through the position of connection of the first signal connection part  31 C and the second signal connection part  32 B. 
     In this case, since signals have the characteristic of being transmitted through a shorter route, a signal is transmitted through the route passing through the position of connection of the first signal connection part  31 C and the second signal connection part  32 B as indicated by a bold solid arrow in  FIG. 7B , which illustrates the case of transmitting a signal from the first signal contact part  31  to the second signal contact part  32 . Thus, according to this embodiment, compared with the case of transmitting a signal through the third signal contact part  33 , it is possible to reduce signal transmission distance so that it is possible to prevent the occurrence of transmission loss in the signal contact  30 . 
     Next, a description is given of the ground contact  40 . The ground contact  40  is connected to the ground member  52  when the plug  50  is attached to the connector  10 . The ground member  52  is connected to the shield line of the cable  54 , and the ground contact  40  is connected to corresponding ground terminal  62  ( FIG. 5 ) of the board  60 . Therefore, the ground contact  40  and the ground member  52  are at ground potential. This prevents entry of a disturbance into the plug pin  51  and the signal contact  30  at the position of connection of the connector  10  and the plug  50 . 
       FIG. 8  is an enlarged view of the ground contact  40 . The ground contact  40 , which is formed of a contact material such as phosphor bronze, includes a first ground contact part  41 , second ground contact parts  42 , and third ground contact parts  43 , which are formed into a unitary structure. The first ground contact part  41  may be a first contact part. The second ground contact parts  42  may be a second contact part. The third ground contact parts  43  may be a third contact part. 
     The first ground contact part  41  includes a ground contact body part  41 A, a pair of plug ground terminal parts  41 B, and first ground connection parts  41 C. The plug ground terminal parts  41 B may be a first terminal part. The first ground connection parts  41 C may be a first connection part. The ground contact body part  41 A is press-fit into the corresponding attachment hole  22  provided in the connector housing  20 . The ground contact body part  41 A is press-fit into the attachment hole  22  so that the ground contact  40  is held by the connector housing  20 . 
     The ground contact body part  41 A has a substantially tubular or cylindrical shape. The plug ground terminal parts  41 B extend from the upper end of the ground contact body part  41 A. The plug ground terminal parts  41 B are connected to the ground member  52  of the plug  50  when the plug  50  is inserted into the connector  10 . Further, the first ground connection parts  41 C are formed at the lower end of the ground contact body part  41 A so as to extend linearly in the downward (Z 2 ) direction. (See also  FIG. 9 .) 
     Further, slits  41 A- 1  are formed in the ground contact body part  41 A so as to be open between the plug ground terminal parts  41 B at the upper end of the ground contact body part  41 A. A support part (not graphically illustrated) to support the above-described contact holding part  21   a  ( FIG. 5 ) is inserted into the slits  41 A- 1 . This support part is formed as part of the connector housing  20  with one end of the support part joined to the contact holding part  21   a  and the other end of the support part joined to the internal wall of the attachment hole  22 . As a result, the contact holding part  21   a  is supported at the substantial center of the attachment hole  22 . Thus, providing the slits  41 A- 1  in the ground contact  40  makes it possible for the ground contact  40  to be inserted into and attached at the attachment hole  22  with the support part formed inside. 
     Referring to  FIG. 9  as well as  FIG. 8 , each second ground contact part  42  has an inverse T-letter shape. The second ground contact part  42  includes a board ground terminal part  42 A in its lower portion and a second ground connection part  42 B in its upper portion. The board ground terminal part  42 A may be a second terminal part. The second ground connection part  42 B may be a second connection part. 
     The board ground terminal part  42 A is connected to a corresponding one of the ground terminals  62  formed on the board  60  with the connector  10  mounted on the board  60 . In this case, the board ground terminal part  42 A is not soldered but is in press contact with the corresponding ground terminal  62  to be electrically connected to the ground terminal  62  (of which a description is given below). 
     Further, according to this embodiment, multiple, for example, three second ground contact parts  42  are provided for each first ground contact part  41 . In a bottom view of the ground contact  40 , the three second ground contact parts  42  are provided at intervals of 120 degrees, so that the ground connection parts  41 C are also provided at intervals of 120 degrees at the lower end of the ground contact body part  41 A in a bottom view of the ground contact  40 . 
     Further, as indicated by double-headed arrows in  FIG. 9 , for good electrical connection between the second ground contact parts  42  and the corresponding ground terminal  62 , the board ground terminal part  42 A has a width W 1  greater than a width W 2  of the second ground connection part  42 B in each second ground contact part  42 . As a result of this configuration, the second ground contact parts  42  have an inverse T-letter shape as described above. Further, each board ground terminal part  42 A is provided with a connection projection  42 C projecting downward (in a direction to face the corresponding ground terminal  62  or the Z 2  direction) from the board ground terminal part  42 A. 
     According to the above-described configuration of the second ground contact parts  42 , even if the board ground terminal parts  42 A are inclined relative to the ground terminal  62  in the contact, at least one of the second ground contact parts  42  and at least one of the connection projections  42 C are connected to the corresponding ground terminal  62  without fail, so that it is possible to ensure electrical connection between the ground contacts  40  and the board  60 . 
     Implementation of one or more of providing each first ground contact part  41  with multiple second ground contact parts  42 , making the width W 1  of the board ground terminal part  42 A greater than the width W 2  of the second ground connection part  42 B, and providing the board ground terminal part  42 A with the connection projections  42 C improves the connection between the ground contacts  40  and the board  60 . 
     On the other hand, the second ground connection part  42 B is configured to face the first ground connection part  41 C formed in the corresponding first ground contact part  41  across a gap or space between them with the plug  50  being not attached to the connector  10 . As described below, when the plug  50  is attached to the connector  10  or the connector  10  is mounted on the board  60 , the first ground connection part  41 C and the second ground connection part  42 B are electrically connected. 
     Each third ground contact part  43  has substantially the same configuration as the above-described third signal contact part  33 . The third ground contact part  43  includes an elastic deformation part  43 A, an upper end part  43 B, and a lower end part  43 C. The elastic deformation part  43 A is elastically deformable. The upper end part  43 B and the first ground contact part  41  (the corresponding first ground connection part  41 C) are connected in a unitary structure. The lower end part  43 C and the second ground contact part  42  are connected in a unitary structure. The third ground contact part  43  is elastically deformable so as to allow the second ground contact part  42  to be displaceable in the Z 1  and the Z 2  direction relative to the first ground contact part  41  in  FIG. 9 . Further, the elastic deformation of the third ground contact part  43  generates an elastic restoring force in the third ground contact part  43 . 
     Upward displacement of the second ground contact part  42  (in the Z 1  direction) relative to the first ground contact part  41  generates an elastic force (elastic restoring force) to urge the second ground contact part  42  in the downward (Z 2 ) direction in the elastic deformation part  43 A. This elastic force serves as a force to bring the board ground terminal part  42 A into press contact with the board  60  when the connector  10  is mounted on the board  60 . 
     On the other hand, as shown enlarged in  FIG. 9 , the first ground connection part  41 C of the first ground contact part  41  extends in the Z 2  direction from the position of connection of the upper end part  43 B of the third ground contact part  43  and the first ground contact part  41 . Further, with no external force applied, the third ground contact part  43  keeps the first ground connection part  41 C and the second ground connection part  42 B of the second ground contact part  42  facing each other across a narrow gap (or in proximity to each other). 
     Therefore, if the plug  50  is attached to the connector  10  so as to cause the ground member  52  to come into contact with the ground contact  40  so that the ground contact  40  is pressed and displaced, the first ground connection parts  41 C are also displaced to come into contact with the corresponding second ground connection parts  42 B. Thereby, the first ground connection parts  41 C and the second ground connection parts  42 B are electrically connected. 
     Next, a description is given of the board  60  on which the connector  10  having the above-described configuration is mounted. 
     The board  60 , which is a multilayer printed wiring board, has the signal terminals  61  and the ground terminals  62  provided on its surface.  FIG. 10  and  FIG. 11  illustrate a structure of the signal terminals  61  and the ground terminals  62 .  FIG. 10  illustrates a signal terminal  61  and a corresponding ground terminal  62  corresponding to a pair of a signal and a ground contact  30  and  40 .  FIG. 11  illustrates multiple signal and ground terminals  61  and  62  provided on the board  60 . 
       FIG. 12  is a top-side perspective view of the connector  10 . Referring to  FIG. 12  as well as  FIG. 1  and  FIG. 5 , one signal contact  30  and one ground contact  40  are attached in a pair to each attachment hole  22  of the connector housing  20 . Accordingly, in correspondence to the contacts  30  and  40  attached at each attachment hole  22 , a signal terminal  61  corresponding to the signal contact  30  and a ground terminal  62  corresponding to the ground contact  40  are formed in a pair on the board  60 . 
     Referring to  FIG. 10 , the ground terminal  62  has an annular shape corresponding to the tubular shape of the ground contact body part  41 A of the first ground contact part  41 . The ground terminal  62  is shaped like a hexagonal nut to have a hexagonal outer shape with a circular hole inside. The signal terminal  61  is formed at the center position of the region inside the ground terminal  62 . The signal terminal  61  and the ground terminal  62  include a via connection part  61 A and via connection parts  62 A, respectively, which are electrically connected to corresponding vias formed in the board  60 . Thereby, the terminals  61  and  62  are electrically connected to internal layer interconnects (not graphically illustrated) formed in the board  60 . 
     Positioning holes  63  ( FIG. 5 ) into which the corresponding projections  26  for positioning the connector  10  are inserted and insertion holes (not graphically illustrated) into which fixation screws for fixing the connector  10  to the board  60  are inserted are provided in the board  60 . 
     Next, a description is given of a method of assembling the connector  10  having the above-described configuration and a method of mounting the assembled connector  10  on the board  60 . 
     Before assembling the connector  10 , the connector housing  20 , the signal contacts  30 , the ground contacts  40 , and the bottom plate  29 , manufactured in advance in separate processes to be shaped as described above, are prepared. Then, the signal contacts  30  and the ground contacts  40  are inserted into and attached to the corresponding attachment holes  22  from the bottom side of the connector housing  20 . At this point, as described above, the signal contacts  30  are attached to the corresponding contact holding parts  21   a , and the ground contacts  40  are press-fit into the corresponding attachment holes  22 . 
       FIG. 4  and  FIG. 12  are a bottom-side perspective view and a top-side perspective view, respectively of the connector housing  20  where a signal contact  30  and a ground contact  40  are attached at each of the attachment holes  22  formed in the connector housing  20 . 
     As illustrated in  FIG. 4 , the step part  25  is formed in the connector housing  20  on its bottom side, and the positioning projections  26  and the screw holes  27  are formed in the step part  25 . The board signal terminal parts  32 A of the signal contacts  30  and the board ground terminal parts  42 A of the ground contacts  40  project from (the bottom surface part of) the step part  25  with the contacts  30  and  40  attached to the connector housing  20 . 
     After the contacts  30  and  40  are attached to the connector housing  20  as described above, the bottom plate  29  is attached to the step part  25 . The bottom plate  29  has through holes formed at positions corresponding to the positioning projections  26  and positions opposed to the screw holes  27 . The bottom plate  29  further includes terminal holes  29 A ( FIG. 3 ) formed at positions corresponding to the board signal terminal parts  32 A and the board ground terminal parts  42 A. Screws  28  are screwed into the screw holes  27  through the corresponding through holes of the bottom plate  29  attached to the step part  25 , so that the bottom plate  29  is fixed to the connector housing  20 . 
     At this point, the board signal terminal parts  32 A and the board ground terminal parts  42 A project from the bottom plate  29  fixed to the step part  25  as well.  FIG. 13  is an enlarged view of part of the bottom plate  29 , illustrating positions where terminal holes  29 A are formed. As illustrated in  FIG. 13 , the board signal terminal parts  32 A and the board ground terminal parts  42 A project in the downward (Z 2 ) direction from the bottom plate  29  through the corresponding terminal holes  29 A. 
     Further, the terminal parts  32 A and  42 A are not fixed but loosely fit in the terminal holes  29 A so as to be displaceable (movable) in the terminal holes  29 A. The positioning projections  26  also project from the bottom plate  29  fixed to the step part  25 . 
     As described above, the contacts  30  and  40  are attached to the connector housing  20  by simply inserting them into the corresponding attachment holes  22 . This facilitates manufacturing of the connector  10 . Further, attachment of the bottom plate  29  to the connector housing  20  prevents removal of the contacts  30  and  40 . This increases the reliability of the connector  10 . 
     Next, a description is given of a method of mounting the connector  10  on the board  60 . In mounting the connector  10  on the board  60 , first, the positioning projections  26  are inserted into the positioning holes  63  formed in the board  60  so as to position the connector  10  relative to the board  60 . (See, for example,  FIG. 5 .) In this state, the board signal terminal parts  32 A and the board ground terminal parts  42 A projecting from the bottom plate  29  are positioned relative to the signal terminals  61  and the ground terminals  62 , respectively. 
     Next, fixation screws (not graphically illustrated) are inserted into the insertion holes  24  formed in the flange parts  23  of the connector housing  20 , and the connector  10  is fixed to the board  60  using these fixation screws. As a result of screwing (fixing) the connector  10  to the board  60 , the board signal terminal parts  32 A and the board ground terminal parts  42 A projecting from the bottom plate  29  are relatively pressed. As a result, the elastic deformation parts  33 A of the third signal contact parts  33  and the elastic deformation parts  43 A of the third ground contact parts  43  deform elastically so as to press the board signal terminal parts  32 A and the board ground terminal parts  42 A against the signal terminals  61  and the ground terminals  62 , respectively, with their elastic restoring forces. 
     Thus, the electrical connection between the signal and the ground contacts  30  and  40  and the board  60  is established by pressing the terminal parts  32 A and  42 A against the terminals  61  and  62 , respectively, with the elastic restoring forces of the elastic deformation parts  33 A and  43 A. Therefore, even if there is attachment error in attaching the signal contacts  30  and/or the ground contacts  40  to the connector housing  20  or even if the connector housing  20 , the signal contacts  30 , and/or the ground contacts  40  include manufacturing error, such error is absorbed by the elastic deformation of the elastic deformation parts  33 A and/or the elastic deformation parts  43 A. Further, since the terminal parts  32 A and  42 A are pressed against the terminals  61  and  62 , respectively, electrical connection is ensured. Therefore, the connection reliability of the connector  10  and the board  60  is increased. 
     Further, according to this embodiment, the electrical connection between the terminal parts  32 A and  42 A and the terminals  61  and  62  is established by pressing the terminal parts  32 A and  42 A against the terminals  61  and  62 , respectively, without using soldering, which is a common method of connecting a connector and a board. Accordingly, the connector  10  is removed with ease from the board  60  when it is necessary to remove the connector  10  from the board  60  for purposes such as repairs. Therefore, the repairability of the connector  10  is improved. 
     Second Embodiment 
     A description is given of a second embodiment according to the present invention. 
       FIG. 14  is an exploded perspective view of a connector  100  according to the second embodiment.  FIGS. 15A and 15B  are a top-side perspective view and a bottom-side perspective view, respectively, of the connector  100 , illustrating its exterior. 
     Like the connector  10  of the first embodiment, the connector  100  is to be surface-mounted on a board (not graphically illustrated), and electrically connects inserted plugs  150  and the board. The connector  100  includes a connector housing  120 , signal contacts  130 , and ground contacts  140 . 
     The connector housing  120  is formed by molding thermoplastic resin such as LCP (liquid crystal polymer). Multiple attachment holes  121  at which the signal contacts  130  and the ground contacts  140  are attached to the connector housing  120  are formed through the connector housing  120 . Further, insertion holes  124 , into which bolts  123  (or screws) are to be inserted that are used at the time of mounting the connector  100  on the board, are formed in the corresponding four corners of the connector housing  120 . Further, a step part  122  for attaching the bottom plate  29  (described above in the first embodiment) is formed on the bottom surface of the connector housing  120 . 
     A description is given of the plugs  150  to be attached to the connector  100 . The plugs  150  are those to be attached to a high-speed transmission cable such as a coaxial cable. 
       FIG. 16  is a perspective view of the plug  150 , illustrating its exterior. 
     Referring to  FIG. 16 , the plug  150  includes a plug pin  151  and a ground member  152 . The core wire and the shield line of a coaxial cable (not graphically illustrated) to which the plug  150  is attached are connected to the plug pin  151  and the ground member  152 , respectively. 
     As illustrated in  FIG. 16 , the ground member  152  has multiple slits  152 A formed from its end toward its base, so that the end of the ground member  152  is divided into multiple portions. This shape allows the ground member  152  to be pressed and elastically deformed toward the plug pin  151  side in response to external pressure. 
       FIG. 17  is a perspective view of the signal contact  130 , illustrating its exterior. 
     The signal contact  130 , which is formed of a contact material such as phosphor bronze, includes a signal contact first terminal part  131  for connection to the plug pin  51 , a signal contact body part  132 , and a signal contact second terminal part  133  for connection to the board, which are formed into a unitary structure. The signal contact first terminal part  131  may be a third terminal part. The signal contact second terminal part  133  may be a fourth terminal part. 
     The signal contact first terminal part  131  establishes electrical connection to the plug pin  151  by holding the plug pin  151  when the plug  150  is attached to the connector  100 . The signal contact first terminal part  131  is not limited to this configuration, and may be configured to be electrically connected to the plug pin  151  by coming into press contact with the plug pin  151  from one side. Since the plug pin  151  is connected to the signal line (core wire) of the cable as described above, a signal transmitted through the cable is transmitted to the signal contact  130  through the plug pin  151 . A description is given below of the signal contact second terminal part  133 . 
       FIG. 18  is a perspective view of the ground contact  140 , illustrating its exterior. 
     The ground contact  140 , which is formed of a contact material such as phosphor bronze, includes ground contact first terminal parts  141  for connection to the ground member  152 , a substantially cylindrical ground contact body part  142 , and ground contact second terminal parts  143  for connection to the board, which are formed into a unitary structure. The ground contact first terminal parts  141  may be a first terminal part. The ground contact second terminal parts  143  may be a second terminal part. 
     Referring to  FIG. 18 , for example, four ground contact first terminal parts  141  are formed at predetermined circumferential intervals on one end of the ground contact body part  142 , and three ground contact second terminal parts  143  are formed at predetermined circumferential intervals (such as 120° angular intervals) on the other end of the ground contact body part  142 . Providing three or more ground contact second terminal parts  143  in this manner stabilizes transmission of a ground signal. 
     When the plug  150  is attached to the connector  100 , the ground contact first terminal parts  141  are pressed outward by the ground member  152 , and establish electrical connection to the ground member  152  by holding it with the restoring force of the ground contact first terminal parts  141 . The ground member  152  is connected to the shield line of the cable, and the ground contact  140  is connected to a ground terminal on the board. Accordingly, the ground contact  140  and the ground member  152  are at ground potential. A description is given below of the ground contact second terminal parts  143 . 
     Like the signal contact  30  of the first embodiment, the signal contact  130  is contained and held inside the ground contact body part  142  of the ground contact  140 . A description of this structure is omitted. This structure prevents entry of a disturbance into the plug pin  151  and the signal contact  130  at the position of connection of the connector  100  and the plug  150 . 
       FIG. 19  is a schematic diagram illustrating how the plug  150  is connected to the connector  100 . 
     When the plug  150  is connected to the connector  100 , the ground member  152  elastically deforms toward the plug pin  151  side and the ground contact first terminal parts  141  elastically deform outward, so that the plug  150  is stably fixed by their respective restoring forces. 
     At this point, the connection of the ground contact first terminal parts  141  to the ground member  152  is ensured at two points: one on the entrance side and the other on the base side. This avoids generation of a stub to the ground signal transmission line and prevents entry of noise in high-frequency transmission. 
     A description is given below of connection of the connector  100  and the board. 
     In the connector  100  of this embodiment, like in the connector  10  of the first embodiment, contact members elastically deform upon attachment of the connector housing  120  to the board with screws or bolts, so as to come into press contact with corresponding electrodes on the board with their restoring forces, thereby establishing stable electrical connection. Reference may be made to the first embodiment for the board-side electrode structure of this embodiment, and a description thereof is omitted. 
     Referring to  FIG. 17 , the signal contact second terminal part  133  includes a signal contact first member  133 A and a signal contact second member  133 B. The signal contact first member  133 A may be a third member. The signal contact second member  133 B may be a fourth member. 
     The signal contact first member  133 A extends substantially linearly from the signal contact body part  132  toward the board side. Further, the signal contact second member  133 B, which has a curved shape so that an end part  133 Ba thereof faces the signal contact first member  133 A across a gap, is elastically deformable. The signal contact first member  133 A and the signal contact second member  133 B are formed by working a plate material serving as a base material by press blanking and further bending the plate material into a predetermined shape as illustrated. 
     When the connector  100  is attached to the board with screws or bolts, the signal contact second member  133 B elastically deforms so that its end part  133 Ba comes into press contact with the signal contact first member  133 A. Further, a board-side end part  133 Bb of the signal contact second member  133 B, which is designed to come into contact with a board-side electrode, comes into press contact with a corresponding board-side electrode with the restoring force of the signal contact second member  133 B. 
     Signals have the characteristic of being transmitted through a shorter route. Therefore, a signal flows to the board through a transmission path from the signal contact first terminal part  131  to the board-side end part  133 Bb via the signal contact body part  132 , the signal contact first member  133 A, and the end part  133 Ba of the signal contact second member  133 B. 
     On the other hand, as illustrated in  FIG. 20 , which is an enlarged perspective view of part of the ground contact  40 , each of the ground contact second terminal parts  143  includes a ground contact first member  143 A and a ground contact second member  143 B. The ground contact first member  143 A may be a first member. The ground contact second member  143 B may be a second member. 
     The ground contact first member  143 A extends substantially linearly from the ground contact body part  142  toward the board side. Further, the ground contact second member  143 B, which has a curved shape so that an end part  143 Ba thereof faces the ground contact first member  143 A across a gap, is elastically deformable. The ground contact first member  143 A and the ground contact second member  143 B are formed by working a plate material serving as a base material by press blanking and further bending the plate material into a predetermined shape as illustrated. 
     When the connector  100  is attached to the board with screws or bolts, the ground contact second member  143 B elastically deforms so that its end part  143 Ba comes into press contact with the ground contact first member  143 A. Further, a board-side end part  143 Bb of the ground contact second member  143 B, which is designed to come into contact with a board-side electrode, comes into press contact with a corresponding board-side electrode with the restoring force of the ground contact second member  143 B. The board-side end parts  133 Bb and  143 Bb are also illustrated in  FIG. 21 , which is an enlarged view of part of the bottom surface of the connector  100 . 
     Signals have the characteristic of being transmitted through a shorter route. Therefore, a signal flows to the board through a transmission path from the ground contact first terminal parts  141  to the board-side end parts  143 Bb via the ground contact body part  142 , the ground contact first members  143 A, and the end parts  133 Ba of the ground contact second members  143 B. 
     Thus, according to the connector  100  of this embodiment, contact members are stably connected to the board without being soldered. This facilitates checking or repairing the connector  100 . 
     Further, even if there is attachment error in attaching the signal contacts  130  and/or the ground contacts  140  to the connector housing  120  or even if the connector housing  120 , the signal contacts  130 , and/or the ground contacts  140  include manufacturing error, such error is absorbed by the elastic deformation of the signal contact second members  133 B and/or the ground contact second members  143 B. 
     Further, since the contact points are formed by press contact, it is possible to ensure electrical connection. As a result, the reliability of the connection of the connector  100  and the board is increased. 
     Further, as illustrated in  FIG. 17  and  FIG. 20 , while the curved members (the signal contact second members  133 B and the ground contact second members  143 B) may have a certain size to have elastic forces, the signal transmission path may be relatively short. Accordingly, transmission loss, which may be generated depending on transmission path length, is controlled. This makes it possible to respond to high-frequency signal transmission. 
     The present invention may be applied to the manufacture of computers and their peripheral devices. 
     According to an aspect of the present invention, a connector is provided whose connection to a board is more reliable and whose mounting on the board is more simplified. 
     According to an aspect of the present invention, between a first contact part and a second contact part, an elastically deformable third contact part is provided between the first contact part and the second contact part in a contact. Accordingly, even if a board warps or there is manufacturing error in connector components, the third contact part elastically deforms to absorb such a warping of the board or manufacturing error. This increases the reliability of the electrical connection between the contact and the board. 
     Further, the (second) terminal part of the second contact part is electrically connected to an interconnect of the board by coming into press contact with the interconnect through the elastic force of the third contact part. This makes it unnecessary to fix the terminal part to the interconnect of the board by such a process as soldering, thus facilitating the mounting of the connector onto the board as well as improving the repairability of the connector. 
     The present invention is not limited to the specifically disclosed embodiments, and variations and modifications may be made without departing from the scope of the present invention. 
     The present application is based on and claims the benefit of priority of Japanese Priority Patent Applications No. 2008-284133, filed on Nov. 5, 2008, and No. 2009-164113, filed on Jul. 10, 2009, the entire contents of which are incorporated herein by reference.