JP5331040B2 - Electric field communication system - Google Patents

Description

  The present invention relates to a technique for transmitting and receiving information using an electric field.

  2. Description of the Related Art An electric field communication device that transmits and receives data by inducing an electric field in an electric field transmission medium such as a human body has been developed (see Non-Patent Document 1).

  An electric field communication device that can use a human body as a transmission path can be used, for example, in a system that manages entry / exit. Specifically, an electric field communication device that transmits ID information is carried by a user, and an electrode of the electric field communication device that performs authentication by receiving ID information on a wall or floor near a gate or a gate that manages entrance and exit. Deploy. When the user approaches the electrodes arranged on the wall or floor, a transmission path through the user is established, and ID information is transmitted and received for authentication. When the user is authenticated, the door and gate are opened.

  FIG. 10 is a schematic diagram for explaining a conventional electric field communication system that manages entry / exit by transmitting / receiving ID information. An installation terminal 41 that performs electric field communication is installed on a wall near the door 5 that manages entry / exit, and the user 100 holds a portable terminal 42 that transmits ID information by electric field communication. ID information is transmitted and received between the installation terminal 41 and the portable terminal 42, authentication is performed using the ID information, and opening / closing of the door 5 is controlled. More specifically, the installation terminal 41 transmits a polling signal through the flat plate electrode 41 a connected to the installation terminal 41. The mobile terminal 42 that has received the polling signal transmits ID information. Then, the installation terminal 41 receives the ID information and performs authentication.

  As shown in FIG. 10, the plate electrode 41 a is disposed on the surface of the installation terminal 41. Alternatively, the flat plate electrode 41a may be disposed on the wall, and the installation terminal 41 may be disposed at a position away from the flat plate electrode 41a. In either case, the flat plate electrode 41 a is arranged in parallel to the door 5. The polling signal is radiated in the vertical direction of the plate electrode 11a as shown by the arrow in FIG. That is, the polling signal is radiated from the front of the door 5 toward the air.

"Human area network technology using the human body as a signal path" Red Tacton "", NTT Technical Journal, 2005, Vol. 17, No. 3, p.34-38

  However, in the conventional electric field communication system, when the user 100 holding the mobile terminal 42 does not intend to open the door 5 and passes the vicinity of the door 5 by about 1 to 2 m away, the polling transmitted by the installation terminal 41 is transmitted. There was a problem that the portable terminal 42 received the signal, the communication was started, and the installation terminal 41 malfunctioned.

  The present invention has been made in view of the above, and an object thereof is to prevent unintended communication between an installation terminal and a mobile terminal that use electric field communication.

An electric field communication system according to the present invention is an electric field communication system having an installation terminal that transmits and receives information using an electric field and a portable terminal, and the installation terminal is radiated from a flat plate electrode and a flat plate surface of the flat plate electrode. A potential-fixed metal member disposed in a space where the electric field is radiated so as to limit the reach of the electric field by changing the traveling direction of the electric field, and the portable terminal has an electric field radiated from the plate electrode. When the information request signal is detected and received, communication is started between the installation terminal and the portable terminal.

  In the electric field communication system, the flat plate electrode is an electrode in which an electric field radiation surface is inclined with respect to a horizontal direction.

  In the electric field communication system, the metal member is a metal plate arranged in a direction perpendicular to the flat plate electrode.

  ADVANTAGE OF THE INVENTION According to this invention, the communication which is not intended between the installation terminal and portable terminal using electric field communication can be prevented.

It is a schematic diagram which shows the structure of the electric field communication system in 1st Embodiment. It is a schematic diagram which shows the structure of another electric field communication system in 1st Embodiment. It is a schematic diagram which shows the structure of the electric field communication system in 2nd Embodiment. It is a schematic diagram which shows the structure of another electric field communication system in 2nd Embodiment. It is a schematic diagram which shows the structure of another electric field communication system in 2nd Embodiment. It is a schematic diagram which shows the structure of another electric field communication system in 2nd Embodiment. It is a schematic diagram which shows the structure of the electric field communication system in 3rd Embodiment. It is a schematic diagram which shows the structure of another electric field communication system in 3rd Embodiment. It is a perspective view which shows the structure of the metal plate of the electric field communication system of FIG. It is a schematic diagram for demonstrating the conventional electric field communication system.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a schematic diagram showing the configuration of the electric field communication system according to the first embodiment. The electric field communication system shown in the figure is a system that manages entry / exit by controlling the door 5 by transmitting / receiving ID information and authenticating it.

  An installation terminal 11 that performs electric field communication is installed on the door 5 or a wall near the door 5. A user 100 holds a portable terminal 12 that transmits ID information by electric field communication. The plate electrode 11 a is disposed on the surface of the installation terminal 11. The installation terminal 11 is installed with a slight inclination with respect to the front surface of the door 5 so that the flat plate electrode 11a faces obliquely upward. In addition, the flat electrode 11a may be inclined and installed on the door 5 or the wall, and the installation terminal 11 may be installed at a position away from the flat electrode 11a.

  Although not shown, the installation terminal 11 includes a transmission circuit that transmits an electric field based on information to be transmitted through the plate electrode 11a, a reception circuit that receives the signal by detecting the electric field using the plate electrode 11a, and an ID included in the received signal. A control circuit that authenticates information and controls the door 5 is provided. Although not shown, the portable terminal 12 reads out the ID information from the electrode for electric field communication, the storage means storing the ID information for identifying the user 100, and the storage means, and transmits the electric field based on the ID information through the electrode. And a receiving circuit for detecting an electric field by an electrode and receiving a signal.

  When the user 100 holding the mobile terminal 12 approaches the door 5, the mobile terminal 12 receives a polling signal transmitted from the installation terminal 11. The polling signal is a signal for requesting transmission of ID information. And the portable terminal 12 transmits ID information. When the installation terminal 11 receives the ID information and the authentication is successful, the door 5 is opened.

In the present embodiment, since the flat plate electrode 11a is disposed slightly inclined with respect to the front surface of the door 5, the electric field radiated from the flat plate electrode 11a proceeds not diagonally but diagonally upward , and further, the arrow in FIG. As shown in FIG. 6, the electric field does not reach far away from the metal part of the door 5 or the building as compared with the conventional example. The angle at which the plate electrode 11a is tilted is set according to the arrangement position of the plate electrode 11a and the surrounding environment so that the electric field does not reach beyond a desired range. By limiting the reach of the electric field, it is possible to increase the reception sensitivity and improve the degree of design freedom while suppressing the false authentication rate. In FIG. 1, the radiation surface of the electric field of the flat plate electrode 11a is inclined upward, but it may be inclined downward with respect to the horizontal direction.

FIG. 2 is a schematic diagram showing a configuration of another electric field communication system according to the first embodiment. In contrast to the one shown in FIG. 1, a door 5 or a metal plate 13 is provided on the wall. The potential of the metal plate 13 is fixed by grounding. As shown in FIG. 2, by providing the metal plate 13 in the electric field emission direction, a part of the electric field is absorbed by the metal plate 13 and the reach distance of the polling signal transmitted by the installation terminal 11 is suppressed. As a result, since the mobile terminal 12 does not receive the polling signal unless the user 100 is closer to the door 5 than before, it is possible to suppress erroneous authentication.

  As described above, according to the present embodiment, the flat plate electrode 11 a connected to the installation terminal 11 installed in the vicinity of the door 5 is installed with a slight inclination with respect to the front direction of the door 5. Since the electric field radiated by 11a proceeds not in the horizontal direction but in an inclined direction and further toward the metal part such as the door 5 or the building, the reach of the polling signal transmitted by the installation terminal 11 can be suppressed, and the user Communication which 100 does not intend can be prevented.

  According to the present embodiment, by providing the metal plate 13 in the direction in which the flat plate electrode is inclined (electric field emission direction), the electric field radiated by the flat plate electrode 11a is absorbed by the metal plate 13, so the reach distance of the polling signal Is suppressed.

[Second Embodiment]
FIG. 3 is a schematic diagram illustrating a configuration of the electric field communication system according to the second embodiment. The electric field communication system shown in the figure is a system that manages entry / exit by controlling the door 5 by transmitting / receiving ID information and authenticating, as in the first embodiment.

  An installation terminal 21 that performs electric field communication is installed on the door 5 or a wall near the door 5. The user 100 holds the portable terminal 22 that transmits ID information by electric field communication. The flat plate electrode 21 a is disposed on the surface of the installation terminal 21. The flat plate electrode 21a may be installed on the door 5 or the wall, and the installation terminal 21 may be installed at a position away from the flat plate electrode 21a. In addition, a metal plate 23 whose potential is fixed by grounding or the like is disposed on the floor in front of the door 5 in a direction perpendicular to the plate electrode 21a. The metal plate 23 has such a size that the user 100 holding the mobile terminal 22 spreads in a range in which the user 100 can contact the flat plate electrode 21a.

  As in the first embodiment, the installation terminal 21 includes a transmission circuit that transmits a signal using an electric field, a reception circuit that detects the electric field and receives a signal, and a control circuit that controls the door 5 based on the received information. Have. The portable terminal 22 also has a storage unit that stores electrodes for performing electric field communication, a transmission circuit, a reception circuit, and ID information for identifying the user 100. Communication between the installation terminal 21 and the mobile terminal 22 is started when the mobile terminal 22 receives the polling signal transmitted by the installation terminal 21.

  In the second embodiment, the plate electrode 21a radiates an electric field in the front direction of the door 5, but the radiated electric field proceeds toward the metal plate 23 and is absorbed. As a result, the polling signal transmitted by the installation terminal 21 can be received in a range where the plate terminal 21a can be contacted in the vicinity of the door 5. As shown in FIG. 3, when the user 100 stands at a position slightly away from the door 5, communication is not performed between the installation terminal 21 and the portable terminal 22 held by the user 100, so that the door A user 200 who does not hold a mobile terminal existing in the vicinity of 5 cannot open the door 5.

  FIG. 4 is a schematic diagram showing a configuration of another electric field communication system according to the second embodiment. It differs from what was shown in FIG. 3 by the point which has arrange | positioned the metal plate 24 on the ceiling instead of the metal plate 23 arrange | positioned on the floor. The potential of the metal plate 24 is fixed by being grounded or the like, and the metal plate 24 has a size that spreads in a range in which the user 100 holding the mobile terminal 22 can contact the flat plate electrode 21a.

  Even when the metal plate 24 is arranged on the ceiling, since the electric field radiated from the flat plate electrode 21a goes to the metal plate 24, the reach of the polling signal transmitted by the installation terminal 21 can be suppressed.

  FIG. 5 is a schematic diagram showing a configuration of still another electric field communication system according to the second embodiment. In the electric field communication system shown in FIG. 5, the potential-fixed metal plate 25 is disposed so as to face the door 5 and delimit a position where the user 100 holding the mobile terminal 22 can contact the flat plate electrode 21 a.

  In the case of the configuration shown in FIG. 5, since the electric field radiated from the flat plate electrode 21 a does not reach the mobile terminal 22 beyond the metal plate 25, the user 200 who does not hold the mobile terminal is prevented from opening the door 5. Is possible. Instead of the metal plate 25, a metal member such as a metal column may be installed.

  The size and arrangement position of the metal plates 23, 24, and 25 are determined by the arrangement position of the plate electrode 21a and the surrounding environment so that the electric field does not reach beyond a desired range.

  Moreover, as shown in FIG. 6, the structure provided with the metal plate 26 also in the upper part of the position which can contact the flat plate electrode 21a may be sufficient.

  As described above, according to the present embodiment, by arranging the potential-fixed metal plate 23 in the electric field radiation direction of the flat plate electrode 21a, the range in which the electric field radiated by the flat plate electrode 21a reaches can be suppressed and used. Communication that is not intended by the person 100 can be prevented. In the second embodiment, the flat plate electrode 21a connected to the installation terminal 21 installed in the vicinity of the door 5 as shown in FIG. The range in which the electric field radiated by the plate electrode 21a reaches can be suppressed.

[Third Embodiment]
FIG. 7 is a schematic diagram showing the configuration of the electric field communication system according to the third embodiment. As in the first and second embodiments, the electric field communication system shown in the figure is a system that manages entry / exit by controlling the door 5 by transmitting and receiving ID information and authenticating it.

  An installation terminal 31 that performs electric field communication is installed on the floor in front of the door 5 so that the flat plate electrode 31a is on the upper surface. A user 100 holds a portable terminal 32 that transmits ID information by electric field communication. A metal plate 33 whose potential is fixed by grounding or the like is disposed on the ceiling facing the flat plate electrode 31a. The metal plate 33 is large enough to allow the user 100 holding the portable terminal 32 to come into contact with the flat plate electrode 31a. The third embodiment is different from the first and second embodiments in that a flat plate electrode 31a is arranged on the floor.

  As in the first and second embodiments, the installation terminal 31 includes a transmission circuit that transmits a signal using an electric field, a reception circuit that detects the electric field and receives a signal, and a control that controls the door 5 based on the received information. It has a circuit. The portable terminal 32 also has storage means that stores electrodes for performing electric field communication, a transmission circuit, a reception circuit, and ID information for identifying the user 100. Communication between the installation terminal 31 and the portable terminal 32 is started when the portable terminal 32 receives the polling signal transmitted by the installation terminal 31.

  The flat plate electrode 31 a radiates an electric field toward the ceiling as indicated by an arrow in FIG. 7, and the radiated electric field advances toward the metal plate 33. Therefore, the polling signal transmitted by the installation terminal 31 can be received within a range where the flat electrode 31a can be contacted in the vicinity of the door 5. Even when the metal plate 33 is arranged on the door 5 or the wall, the radiated electric field is directed to the metal plate 33, so that the same effect can be expected.

  FIG. 8 is a schematic diagram illustrating a configuration of another electric field communication system according to the third embodiment. The electric field communication system shown in FIG. 1 has an installation terminal 31 arranged in a closed space surrounded by a metal member 34. FIG. 9 shows a perspective view of the metal member 34. As shown in the figure, a metal member 34 is disposed so as to surround the flat plate electrode 31a, thereby creating a closed space where a user can enter. The metal member 34 is provided with a door so that a user can enter and exit the closed space. Since the electric field radiated by the plate electrode 31a does not go out of the closed space, communication is performed between the installation terminal 31 and the mobile terminal 32 only when the user 100 holding the mobile terminal 32 enters the closed space. Is done. In addition, by surrounding the flat electrode 31a with the metal member 34, good communication is performed between the installation terminal 31 and the portable terminal 32 without being affected by the radiated electromagnetic field.

  In addition, the metal member 34 may be shaped like a rope, and the flat plate electrode 31a may be enclosed to partition a space in which the user 100 can communicate.

  As described above, according to the present embodiment, the flat plate electrode 31a is installed on the floor in front of the door 5, and the potential-fixed metal plate 33 is installed on the ceiling. Can proceed toward the metal plate 33 and prevent unintended communication by the user 100 located away from the door 5.

  According to the present embodiment, since the flat plate electrode 31a is surrounded by the metal member 34, communication is performed between the installation terminal 31 and the portable terminal 32 only in the enclosed space surrounded by the metal member 34. Communication that is not intended by the person 100 can be prevented. Further, in the enclosed space, good communication can be performed between the installation terminal 31 and the portable terminal 32 without being affected by the radiated electromagnetic field.

11, 21, 31, 41 ... Installation terminal 11a, 21a, 31a, 41a ... Flat plate electrode 12, 22, 32, 42 ... Mobile terminal 13, 23, 24, 25, 26, 33 ... Metal plate 34 ... Metal member 100, 200 ... User

Claims (3)

An electric field communication system having an installation terminal and a mobile terminal that transmit and receive information using an electric field,
The installation terminal is a plate electrode,
A potential-fixed metal member disposed in a space where the electric field is radiated so as to limit the reach by changing the traveling direction of the electric field radiated from the flat plate surface of the flat plate electrode,
An electric field communication system, wherein communication is started between the installation terminal and the portable terminal when the portable terminal detects an electric field radiated from the plate electrode and receives an information request signal.   The electric field communication system according to claim 1, wherein the flat plate electrode is an electrode in which an electric field radiation surface is inclined with respect to a horizontal direction.   3. The electric field communication system according to claim 1, wherein the metal member is a metal plate arranged in a direction perpendicular to the flat plate electrode.

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