Patent Publication Number: US-2009219134-A1

Title: Keyless entry device

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present invention contains subject matter related to Japanese Patent Application No. 2008-049261 filed in the Japanese Patent Office on Feb. 29, 2008, the entire contents of which is incorporated herein by reference. 
     BACKGROUND 
     1. Field of the Disclosure 
     The present invention relates to a keyless entry device which locks and unlocks a door by performing communication between a vehicle-side device and a portable device, and particularly to a keyless entry device which generates an electric field in a human body by a transmission signal and detects the generated electric field to perform communication between a vehicle-side device and a portable device. 
     2. Description of the Related Art 
     Keyless entry devices include a vehicle-side device provided in a vehicle such as an automobile, and perform wireless communication between the vehicle-side device and a portable device carried by a user, to lock and unlock a door when the identification succeeds. There have been proposed keyless entry devices which perform communication between a vehicle-side device and a portable device with a human body interposed therebetween. 
     As a keyless entry device employing electric field communication, the present applicant proposes a device described in Japanese Patent Application No. 2006-230014 (Cross-Referenced U.S. patent application Ser. No. 11/888,718). The keyless entry device includes different electrodes provided on the sides of a surface (outer side) and a back surface (inner side, vehicle body side) of a door handle provided on a door of a vehicle and performs communication via the finger of the human body during the operation of the door handle to perform the identification and the like between a portable device and a vehicle-side device. 
     As the door handle, a door handle in which a handle body having a flap shape is pulled up, a door handle in which a handle body having a flap shape as above is pulled in a right or left direction, a door handle in which a grip portion having a grip shape is held and pulled to the front side, or the like is generally employed. In the above Japanese Patent Application No. 2006-230014, the keyless entry device is applied to a door handle including a grip-type grip portion. 
     When the door is opened, the door handle including the grip-shaped grip portion is operated to be pulled by inserting the finger into the inner side of the grip portion, and when the door is closed, the door handle is operated to press the outer side of the grip portion with the hand.  FIG. 13  shows a circuit diagram of the case where the grip portion is operated. In this drawing, a portion indicated by a broken line is an equivalent circuit and a portion indicated by a full line is an actual wired portion. 
     As shown in  FIG. 13 , when the grip portion is touched with the hand to be operated such that a human body  52  and a vehicle-side electrode  55  provided in a grip portion  54  of the vehicle are made to be close to each other, an equivalent circuit having C 2  is formed between a portable device  51  carried by the user and a vehicle-side electrode  55  with the human body  52  interposed therebetween. At the same time, an equivalent circuit having C 1  is also formed between the vehicle-side electrode  55  and a vehicle body  53  with the human body  52  interposed therebetween. 
     When a signal is sent from the portable device  51 , the signal is transmitted to a vehicle-side device  50  via the human body  52  and the vehicle-side electrode  55 . However, since the equivalent circuit having C 1  is formed between the vehicle-side electrode  55  and the vehicle body  53 , the signal is also transmitted to the side of C 1 . In a conventional keyless entry device employing electric field communication, the electrode has a flat plate shape where a surface and a back surface of the grip portion  54  have the same size. Accordingly, when the grip portion is operated to be pulled by inserting the finger into the inner side of the grip portion  54 , the vehicle body and the electrode on the side of the back surface of the grip portion  54  are close to each other, and the human body  52  is present therebetween. Thus, C 1  shown in  FIG. 13  becomes large and most signals from the portable device  51  are transmitted to the equivalent circuit having C 1 . Accordingly, the vehicle-side device  50  cannot receive a sufficiently strong signal. In addition, the same problem occurs when the signal is sent to the portable device  51  from the vehicle-side device  50 . 
     SUMMARY 
     A keyless entry device according to the invention performs communication between a portable device and a vehicle-side device provided in a vehicle. The portable device includes a portable device controller which performs communication of a signal for identification and a portable device electrode which induces an electric field generated by the signal from the portable device controller in a human body. The vehicle includes on a door a door handle provided with a grip portion having a grip shape, the grip portion of the door handle is provided with a vehicle-side electrode which detects the electric field induced in the human body by the portable device electrode, and the vehicle is provided with a vehicle-side controller to which the signal is input by the electric field detected by the vehicle-side electrode and which performs the identification of the signal. The vehicle-side electrode has at least two of a first face, a second face, an upper face and a lower face, where the first face is opposed to a vehicle body face of the vehicle, the second face is opposed to the vehicle body face of the vehicle and disposed at a position more distant from the vehicle body than the first face, and the upper face and the lower face are orthogonal to the first face and the second face and parallel to each other. The vehicle-side electrode is composed of the faces other than the first face or formed to have the first face having a smaller area than other faces. 
     In the keyless entry device according to the invention, the vehicle-side electrode has the first face and the second face and the first face is formed to be shorter than the second face to reduce an area. 
     In the keyless entry device according to the invention, the grip portion is provided with supporting portions at both ends thereof, each of which is connected to the vehicle body, the supporting portion at one end of the grip portion includes a rotation center portion, the supporting portion at the other end of the grip portion is supported to be freely pulled out of the vehicle body to the outside, and the first face of the vehicle-side electrode is disposed to be close to the other end of the grip portion. 
     In the keyless entry device according to the invention, the vehicle-side electrode is composed of the faces other than the first face and has the upper face and the lower face, and the upper face and the lower face are connected to each other by a connecting face which is opposed to or orthogonal to the vehicle body. 
     In the keyless entry device according to the invention, the upper face and the lower face are formed in a triangle shape having an apex facing the vehicle body. 
     In the keyless entry device according to the invention, the grip portion is provided with supporting portions at both ends thereof, each of which is connected to the vehicle body, the supporting portion at one end of the grip portion includes a rotation center portion, the supporting portion at the other end of the grip portion is supported to be freely pulled out of the vehicle body to the outside, and apexes of the upper face and the lower face are disposed to be close to the other end of the grip portion. 
     In the keyless entry device according to the invention, the vehicle-side electrode has the second face and the second face has a slit formed at one end thereof. 
     In the keyless entry device according to the invention, the grip portion is provided with supporting portions at both ends thereof, each of which is connected to the vehicle body, the supporting portion at one end of the grip portion includes a rotation center portion, the supporting portion at the other end of the grip portion is supported to be freely pulled out of the vehicle body to the outside, and the slit of the second face is formed at one end of the grip portion. 
     According to the keyless entry device of the invention, the vehicle-side electrode has at least two faces from among the first face which is opposed to the vehicle body face of the vehicle, the second face which is opposed to the vehicle body face of the vehicle and disposed at a position more distant from the vehicle body than the first face, and the upper face and the lower face which are orthogonal to the first face and the second face and parallel to each other. Since the vehicle-side electrode is composed of the faces other than the first face or formed to have the first face having a smaller area than other faces, the face of the vehicle-side electrode, which is opposed to the vehicle body face, can be distantly positioned, and the face of the vehicle-side electrode, which is perpendicular to the vehicle body face, can be closely positioned, or the face of the vehicle-side electrode, which is opposed to the vehicle body face, can be reduced. In addition, capacitance generated between the vehicle body and the vehicle-side electrode with the finger interposed therebetween can be reduced and thus loss of the signal transmission can be reduced. 
     Further, according to the keyless entry device of the invention, the vehicle-side electrode has the first face and the second face and the first face is formed to be shorter than the second face to reduce an area. Accordingly, only by reducing the size of the face of the vehicle-side electrode, which is close to the vehicle body face, capacitance generated between the vehicle body and the vehicle-side electrode with the finger interposed therebetween can be reduced and the vehicle-side electrode can be easily formed. 
     Furthermore, according to the keyless entry device of the invention, the first face of the vehicle-side electrode is disposed to be close to the end opposite to the rotation center portion of the grip portion. Accordingly, the area of the electrode on the side that is not touched with the hand in the grip portion is reduced and the area opposed to the vehicle body is thus reduced, and the area of the electrode on the side that is held increases. Therefore, loss can be suppressed and the signal can be more efficiently transmitted. 
     Moreover, according to the keyless entry device of the invention, the vehicle-side electrode is composed of the faces other than the first face and has the upper face and the lower face, and the upper face and the lower face are connected to each other by a connecting face which is opposed to or orthogonal to the vehicle body. Accordingly, the vehicle-side electrode is easily formed by being bent. 
     In addition, according to the keyless entry device of the invention, the upper face and the lower face are formed in a triangle shape having an apex facing the vehicle body. Accordingly, by reducing as much as possible the portion of the vehicle-side electrode, which is close to the vehicle body face, loss of the signal transmission can be further reduced. 
     Further, according to the keyless entry device of the invention, the apexes of the upper face and the lower face are disposed to be close to the end opposite to the rotation center portion of the grip portion. Accordingly, the area of the electrode on the side that is not touched with the hand in the grip portion is reduced and the area of the electrode on the side that is held increases. Therefore, signal loss can be suppressed and the signal can be more efficiently transmitted. 
     Further, according to the keyless entry device of the invention, the vehicle-side electrode has the second face and the second face has a slit formed at one end thereof. Accordingly, the area which is opposed to the vehicle body can be reduced, and the face of the vehicle-side electrode, which is opposed to the finger, can be increased. Therefore, signal loss is reduced and the transmission efficiency can be balanced. 
     Furthermore, according to the keyless entry device of the invention, the slit of the second face is formed at the end on the side of the rotation center portion of the grip portion. Accordingly, the area of the electrode on the side that is not touched with the hand in the grip portion is reduced and the area opposed to the vehicle body is thus reduced, and the area of the electrode on the side that is held with the hand in the grip portion increases. Therefore, signal loss can be suppressed and the signal can be more efficiently transmitted. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view of a keyless entry device according to an embodiment; 
         FIG. 2  is a perspective view of a portable device; 
         FIG. 3  is a schematic view of a door handle provided outside a door; 
         FIG. 4  is a schematic view of the case where the door is opened from the state of  FIG. 3 ; 
         FIG. 5  is a block diagram of the keyless entry device according to the embodiment; 
         FIG. 6  is a schematic side view of a vehicle and a grip portion; 
         FIG. 7  is a perspective view of a vehicle-side electrode of a first example; 
         FIG. 8  is a perspective view of a vehicle-side electrode of a second example; 
         FIG. 9  is a perspective view of a vehicle-side electrode of a third example; 
         FIG. 10  is a perspective view of a vehicle-side electrode of a fourth example; 
         FIG. 11  is a perspective view of a vehicle-side electrode of a fifth example; 
         FIG. 12  is a perspective view of a vehicle-side electrode of a sixth example; and 
         FIG. 13  is a circuit diagram of the case where the grip portion is operated. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     An embodiment of the invention will be described in detail on the basis of the drawings.  FIG. 1  shows a schematic view of a keyless entry device according to this embodiment. As shown in the drawing, in the keyless entry device according to this embodiment, communication is performed via a human body between a vehicle-side device  2  provided in a vehicle  1  and a portable device  3  carried by a user to lock and unlock a door  1   a  by the identification of ID. 
     In  FIG. 2 , a perspective view of the portable device  3  is shown. As shown in the drawing, the portable device  3  is formed in a generally thin box shape and provided with a power source switch  21  at a side portion thereof. On a surface of the portable device  3 , a portable device electrode  22  is disposed at an area indicated by hatching in the drawing. In the case where the portable device electrode  22  and the human body come into contact with or close to each other, an electric field can be induced in the human body from the portable device electrode  22 . By allowing the electric field induced in the human body to be detected by vehicle  1 , the portable device  3  can perform communication with the vehicle-side device  2  via the human body. The arrangement of the portable device electrode  22  is not limited to that shown in  FIG. 2 , and the size and the area at which the portable device electrode is disposed can be arbitrarily set. The portable device electrode  22  may be disposed on the surface of the portable device  3  to be exposed and may be provided on an inner face near the surface of the portable device  3  to the extent that the electric field can be induced in the human body. 
       FIG. 3  is a schematic view showing a door handle  30  provided outside the door  1   a . As shown in the drawing, the door handle  30  includes a grip portion  31  which has a grip shape and is exposed on an outer face of the door  1   a , and supporting portions  32  and  33  which protrude from both ends of the grip portion  31  to the door  1   a  constituting a part of a vehicle body and are supported by the door  1   a . A vehicle-side electrode  12  made of metal is provided in the grip portion  31 . 
     The supporting portion  32  provided at one end of the grip portion  31  is supported rotatably about a rotation center portion  32   a  in the door  1   a . The supporting portion  33  provided at the other end of the grip portion  31  is supported to be freely pulled out of the door  1   a .  FIG. 4  is a schematic view showing the case where the door  1   a  is opened from the state of  FIG. 3 . When the door  1   a  is opened, the user holds and operates the grip portion  31  to be pulled to the front side. At this time, the grip portion  31  is rotated about one end thereof by a predetermined angle, such that the other end separates from the door  1   a . Accordingly, the user performs the operation by mostly holding the grip portion  31  with the hand at a portion near the other end in which the supporting portion  33  of the grip portion  31  is provided. When the door  1   a  is closed, the user operates the grip portion  31  to press an outer face thereof. 
     When the user carrying the portable device  3  holds and operates the grip portion  31  to be pulled in order to open the door  1   a  from the outside of the vehicle, the electric field induced in the human body by the portable device electrode  22  of the portable device  3  can be detected by the vehicle-side electrode  12  in the grip portion  31 . When the identification succeeds, the door  1   a  is unlocked. On the other hand, when the user carrying the portable device  3  operates the grip portion  31  to be pressed in order to close the door  1   a , the electric field induced in the human body by the portable device electrode  22  of the portable device  3  can be detected by the vehicle-side electrode  12  in the grip portion  31 . When the identification succeeds and the door  1   a  is closed, the door  1   a  is locked. In this case, the vehicle-side device  2  performs an unlocking operation when the door  1   a  is locked, and performs a locking operation when the door  1   a  is closed while being unlocked. 
       FIG. 5  shows a block diagram of the keyless entry device according to this embodiment. As shown in the drawing, the vehicle-side device  2  provided in the vehicle  1  includes a vehicle-side controller  10  which performs a variety of control operations, a memory  11  which stores data used for the vehicle-side controller  10 , the above-described vehicle-side electrode  12 , and a locking and unlocking mechanism  13  which performs locking and unlocking operations of the door  1   a . In addition, the portable device  3  includes a portable device controller  20  which stores ID consisting of predetermined bits, performs a variety of control operations and modulates a signal to be output, a power source switch  21 , a portable device electrode  22  and a power source  23 . A modulated signal containing the ID is constantly and repeatedly output to the portable device electrode  22 . 
     The vehicle-side controller  10  includes a determination portion  10   a  which identifies the signal from the portable device  3 , storage means  10   b  which temporarily stores data, and an input portion  1   c  which demodulates the signal on the basis of the detection of the electric field that is performed by each electrode and causes the storage means  10   b  to store the signal. The vehicle-side controller  10  can always receive the signal from the vehicle-side electrode  12 . 
     The memory  11  provided in the vehicle-side device  2  stores a unique ID of the portable device  3  for the vehicle  1 . The determination portion  10   a  of the vehicle-side controller  10  matches the ID included in the signal temporarily stored in the storage means  10   b  with the ID stored in the memory  11 . When the IDs are matched, the determination portion determines that the identification succeeds, and when the IDs are not matched, the determination portion determines that the identification does not succeed. 
     Next, the structure of the vehicle-side electrode  12  provided in the grip portion  31  will be described in detail.  FIG. 6  shows a schematic side view of the vehicle  1  and the grip portion  31 . The vehicle-side electrode  12  is formed to have a plurality of faces in the grip portion  31 . However, the vehicle-side electrode  12  has at least two of four faces intersecting with each other in the grip portion  31 . Four broken lines shown in  FIG. 6  indicate the positions of the faces, respectively, and each of the faces is a face perpendicular to the page including each of the broken lines of  FIG. 6 . 
     As shown in  FIG. 6 , the two faces among the four faces are opposed to the door  1   a  constituting the vehicle body. Among them, one face close to the door  1   a  is a first face  40  and the other face distant from the door  1   a  is a second face  41 . The first face  40  and the second face  41  are opposed to each other. Further, the remaining two faces are an upper face  42  and a lower face  43  orthogonal to the first face  40  and the second face  41  and are parallel to each other. 
     The vehicle-side electrode  12  can obtain larger output by increasing as much as possible an area of a face opposed to the finger while the grip portion  31  is held with the hand to be operated, or reducing the distance with the finger. On the other hand, capacitance generated between a vehicle body face and the vehicle-side electrode with the finger interposed therebetween can be reduced and thereby reducing the loss of signal transmission by not making or reducing a face opposed to the vehicle body face or keeping the face as far away from the vehicle body face as possible. Accordingly, the vehicle-side electrode  12  according to this embodiment is constituted by faces other than the first face  40  among the four faces shown in  FIG. 6 . When the vehicle-side electrode includes the first face  40 , it is formed to have an area of the first face  40 , which is smaller than them of other faces. Specifically, in this embodiment, one of the following first to sixth examples of the vehicle side-electrode  12  is employed. 
       FIG. 7  shows a perspective view of the vehicle-side electrode  12  of the first example. Hereinafter, in  FIGS. 7 to 12 , the grip portion  31  accommodating the vehicle-side electrode  12  is indicated by a broken line. In addition, although not shown in the drawings, the door  1   a  is disposed on the rear side, the supporting portions  32  is disposed on the right side, and the supporting portion  33  is disposed on the left side. In  FIG. 7 , the vehicle-side electrode  12  of the first example is constituted to have the first face  40  and the second face  41  among the four faces shown in  FIG. 6 . The first face  40  and the second face  41  are connected to each other by a side face  45  orthogonal to the first and second faces and the surface of the door  1   a . The vehicle-side electrode  12  is formed by bending a metal plate. 
     In this example, the vehicle-side electrode  12  has the first face  40  and the first face is shorter than the second face  41 . That is, the first face  40  is formed to have a smaller area than the second face  41 . Accordingly, the face of the vehicle-side electrode  12  opposed to the vehicle body face is made relatively small and capacitance generated between the vehicle body and the vehicle-side electrode with the finger interposed therebetween can be reduced. Thus, loss of the signal transmission can be reduced. In addition, since the vehicle-side electrode  12  of this example has both of the first face  40  and the second face  41 , the vehicle-side electrode is closely opposed to a finger in either of the case where the grip portion  31  is held while the door  1   a  is opened, and the case where the grip portion  31  is pressed in order to close the door  1   a . Therefore the communication can be securely performed. 
     In  FIG. 7 , the grip portion  31  is provided with the supporting portion  32  which includes the rotation center portion  32   a  at one end on the right side of the drawing and the supporting portion  33  which is brought near to or away from the door  1   a  at the other end on the left side of the drawing. As described above, the user performs the operation mostly by holding with the hand the portion near the other end in which the supporting portion  33  of the grip portion  31  is provided. Since the vehicle-side electrode  12  is bent backward at the side in which the supporting portion  33  is provided, the first face  40  shorter than the second face  41  is disposed to be close to the side in which the supporting portion  33  of the grip portion  31  is provided. Accordingly, the first face  40  is disposed at a position held with the hand while the grip portion  31  is operated and thus the area of the vehicle-side electrode  12  opposed to the finger can be sufficiently ensured. 
       FIG. 8  shows a perspective view of the vehicle-side electrode  12  of the second example. In  FIG. 8 , the vehicle-side electrode  12  of the second example is constituted to have the second face  41 , the upper face  42  and the lower face  43  among the four faces shown in  FIG. 6 . That is, in this example, the vehicle-side electrode  12  is formed not to have the first face  40 . The second face  41 , the upper face  42  and the lower face  43  of the vehicle-side electrode  12  are formed in a frame shape and the upper face  42  and the lower face  43  are bent so as to extend toward the door  1   a  from upper and lower ends of the second face  41 , respectively. 
     As described above, when the vehicle-side electrode  12  is constituted by only the faces other than the first face  40  closely opposed to the vehicle body face, capacitance generated between the vehicle body and the vehicle-side electrode with the finger interposed therebetween can be reduced. Thus, loss of the signal transmission can be reduced. In addition, since the second face  41  is distant from the vehicle body face, the capacitance generated between the vehicle body and the vehicle-side electrode with the finger interposed therebetween is small. Furthermore, since the upper face  42  and the lower face  43  are faces in a direction perpendicular to the vehicle body face, the capacitance generated between the vehicle body and the vehicle-side electrode with the finger interposed therebetween is also small. While the vehicle-side electrode  12  of this example does not include the first face  40 , it includes the second face  41 , the upper face  42  and the lower face  43 . Therefore, the vehicle-side electrode is opposed to the finger and can perform the communication when the door  1   a  is opened and closed. 
       FIG. 9  shows a perspective view of the vehicle-side electrode  12  of the third example. The vehicle-side electrode  12  of the third example is constituted to have the second face  41 , the upper face  42  and the lower face  43  among the four faces shown in  FIG. 6 , like the vehicle-side electrode  12  of the second example. The second face  41  is constituted as in the second example, but the upper face  42  and the lower face  43  are formed to have a triangle shape and have an apex  44  opposed to the door  1   a , respectively. That is, as compared to the vehicle-side electrode  12  of the second example, the vehicle-side electrode  12  of this example has a shape such that the area on the side of the vehicle body face is cut, and loss of the signal transmission can be further reduced by reducing as much as possible the portion of the vehicle-side electrode  12 , which is close to the vehicle body face. Also in this example, the vehicle-side electrode has the second face  41 , the upper face  42  and the lower face  43 , and thus, while being opposed to the finger, the vehicle-side electrode can perform the communication when the door  1   a  is opened and closed. 
     The apexes  44  are arranged to be close to one side in one of the right and left directions of the vehicle-side electrode  12 . That is, among three sides constituting each of the upper face  42  and the lower face  43 , one of two sides, other than the side in contact with the second face  41 , is shorter than the other. Also in  FIG. 9 , the supporting portion  32  which includes the rotation center portion  32   a  is disposed on the right side of the drawing and thus the user performs the operation by mostly holding with the hand the portion near the left side of the drawing in which the supporting portion  33  of the grip portion  31  is provided. Since the upper face  42  and the lower face  43  of the vehicle-side electrode  12  are formed such that the apexes  44  are close to the side in which the supporting portion  33  is provided, the area of the vehicle-side electrode  12  opposed to the finger can be sufficiently ensured. 
       FIG. 10  shows a perspective view of the vehicle-side electrode  12  of the fourth example. The structure of the vehicle-side electrode  12  of this example is substantially the same as that of the vehicle-side electrode  12  of the third example shown in  FIG. 9 . A different point is that a slit  46  is formed over the range from one end to the center in a horizontal direction in the second face  41 . As described above, since the slit  46  is formed in the second face  41  of the vehicle-side electrode  12  of this example, the area of the second face  41  opposed to the vehicle body face can be reduced and thus capacitance generated between the vehicle body and the vehicle-side electrode with the finger interposed therebetween is reduced, further reducing the loss of the signal transmission. The loss of the signal transmission can be reduced even further as the slit  46  is made to be larger. However, since the area of the vehicle-side electrode  12  opposed to the human body is also reduced, the intensity of the signal detected by the vehicle-side electrode  12  and the signal transmission loss reduction can be balanced by properly setting the size of the slit  46 . 
     Furthermore, the slit  46  is formed on the side in which the supporting portion  32  including the rotation center portion  32   a  in the grip portion  31  is provided and the second face  41  is disposed to be close to the left side of the drawing in which the supporting portion  33  is provided. As described above, the user performs the operation by mostly holding with the hand the portion near the left side of the drawing in which the supporting portion  33  of the grip portion  31  is provided. Accordingly, the area of the vehicle-side electrode  12  opposed to the finger can be sufficiently ensured by the second face  41  disposed to be close to one side. 
       FIG. 11  shows a perspective view of the vehicle-side electrode  12  of the fifth example. In this example, the vehicle-side electrode  12  is constituted to have the upper face  42  and the lower face  43  among the four faces shown in  FIG. 6  and not to have the first face  40  and the second face  41 . The upper face  42  and the lower face  43  are connected to each other by the side face  45  orthogonal to the first and second faces and the surface of the door  1   a . The vehicle-side electrode  12  is formed by bending a metal plate. According to the vehicle-side electrode  12  of this example, since the vehicle-side electrode does not have the first face  40  and the second face  41 , the area opposed to the finger is slightly reduced when the door  1   a  is opened and closed. However, since there is no face opposed to the vehicle body face, capacitance generated between the vehicle body and the vehicle-side electrode with the finger interposed therebetween can be further reduced and loss of the signal transmission can be reduced. 
       FIG. 12  shows a perspective view of the vehicle-side electrode  12  of the sixth example. In the vehicle-side electrode  12  of this example, the upper face  42  and the lower face  43  are formed in a triangle shape and the second face  41  is formed to have a very narrow width. Since the upper face  42  and the lower face  43  are formed such that the apexes  44  of the upper face  42  and the lower face  43  are close to the side in which the supporting portion  33  is provided as in the case of the vehicle-side electrode  12  of the third example, the area of the vehicle-side electrode  12  opposed to the finger can be sufficiently ensured. 
     The embodiments of the invention have been described as above. The invention is not limited to the embodiments and can be modified in various forms without departing from the technical spirit and scope of the invention. For example, in this embodiment, the first face  40 , the second face  41 , the upper face  42  and the lower face  43  intersect with each other in the grip portion  31 , as shown in  FIG. 6 , and the vehicle-side electrode  12  is accommodated in the grip portion  31 . 
     However, one or more of the first face  40 , the second face  41 , the upper face  42  and the lower face  43  may overlap with the surface of the grip portion  31  and the vehicle-side electrode  12  may be exposed to the surface of the grip portion  31 .