JP2012235221A - Electric field communication device for installation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase signal intensity.SOLUTION: An electric field communication device 100 for installation comprises an auxiliary electrode 11' configured to receive a radiative electric field radiated from a portable electric field communication device 300 to space.

Description

  The present invention relates to a technique for performing electric field communication by inducing an electric field from an electrode into an electric field transmission medium.

  2. Description of the Related Art Conventionally, there has been an electric field communication apparatus that induces an electric field based on information (hereinafter referred to as data) to be transmitted to an electric field transmission medium from an electrode and detects an electric field induced in the electric field transmission medium by an electrode to perform communication. It has been proposed (see Patent Document 1).

  This electric field communication device includes a transmission circuit that generates an AC signal modulated according to data from an electrode, and a reception circuit that reads a weak AC electric field in the vicinity of the human body induced by the AC signal and demodulates data. Composed.

  Such an electric field communication device is used in various scenes depending on the application. In general, as shown in FIG. 7, for example, a portable electric field communication device 300 carried by a person H, a floor, a wall, etc. It is used as an installation electric field communication apparatus 100 installed in a predetermined area.

  As shown in FIG. 8, the portable electric field communication device 300 has the first electrode 32 and the second electrode 33 that induce an electric field in the electric field transmission medium, respectively, disposed on the opposing surfaces of the casing that forms the portable electric field communication device 300. The transceiver circuit 31 in the housing corresponding to the transmission circuit and the reception circuit described above induces an electric field based on data in an electric field transmission medium such as a human body to perform electric field communication.

  On the other hand, as shown in FIG. 7 and FIG. 9, the installation electric field communication apparatus 100 sandwiches an insulator between the first electrode 10 and the second electrode 11 that induce an electric field in the electric field transmission medium, etc. An electric field based on data transmitted from the CPU 13 via the I / O circuit 14 is induced by the transmission circuit 15 from the first electrode 10 to an electric field transmission medium such as a human body and output. The electric field received by the second electrode 11 is detected by the electric field detection circuit 161, the data is demodulated by the signal processing circuit 162, the waveform of the data is adjusted by the waveform shaping circuit 17, and then the I / O circuit 14 is used. Output to the CPU 13.

  Thereafter, the CPU 13 executes processing such as authentication based on the received data. The electric field detection circuit 161 and the signal processing circuit 162 constitute a receiving circuit 16 in the installation electric field communication apparatus 100.

  Such an electric field communication device is capacitively coupled to a human body as an electric field transmission medium by an electrode corresponding to an antenna of a normal wireless system, and reads and demodulates an electric field in the vicinity of the human body via this coupling. . Since the signal is transmitted to the human body surface due to capacitive coupling, the signal is transmitted through the human body surface even if the electric field communication device is in the pocket of clothes or installed under the carpet on the floor, and the transmission circuit of both devices And the receiving circuit.

  Here, as shown in FIG. 10, the point of the electric field communication technology is to suppress the radiated electric field radiated into the space from the first electrode 32 of the portable electric field communication device 300 held by the human body H, thereby suppressing mutual interference. Then, it is to realize intuitive communication that is connected by contact using a quasi-electrostatic field propagating on the surface of the human body (see Non-Patent Document 1).

  The radiated electric field is an electric field radiated from the portable electric field communication device 300 to the space, and is detected by the installation electric field communication device 100 before escaping to the earth ground. A stray capacitance C1 is formed between the first electrode 32 of the portable electric field communication device 300 and the second electrode 11 of the installation electric field communication device 100, and the stray capacitance C1 is an electric field communication path formed on the human body surface. The electric field is returned to the installation electric field communication device 100 to act as a capacity on the communication path forming a loop. By detecting this radiation electric field, electric field communication is realized between both devices (see Non-Patent Document 2).

  On the other hand, the quasi-electrostatic field is an electric field via the capacitor C5 or the human body H between the second electrode 33 of the portable electric field communication device 300 and the first electrode 10 of the installation electric field communication device 100.

Japanese Patent Application Laid-Open No. 2004-274452

Sasaki, 3 others, “Modeling of near-body electric field communication and communication quality evaluation”, NTT Technical Journal, January 2010, p.23-27 Mon, 1 outside, "Near body electric field communication technology" Red Tacton "and its application", NTT Technology Journal, January 2010, p.16-19

  However, the communication path between the first electrode 32 on the space side (non-contact side with respect to the human body) of the portable electric field communication device 300 and the electric field communication device 100 for installation has a long distance, and air having a low dielectric constant is between the distance. Since the stray capacitance C1 on the communication path is as small as several pF due to the presence of only, the impedance is large, only a weak electric field displacement occurs, and the signal strength from the portable electric field communication device 300 cannot be increased. there were.

  The present invention has been made in view of the above-mentioned problems, and the object of the present invention is to increase the signal strength.

  The electric field communication device for installation according to claim 1, wherein the electric field communication device for installation is capable of performing electric field communication by inducing an electric field in the electric field transmission medium, and a communication electrode that receives the electric field through the electric field transmission medium; And an auxiliary electrode that is disposed within a certain distance from the portable electric field communication device and that receives a radiated electric field radiated from the portable electric field communication device to the space.

  According to the present invention, since the auxiliary electrode for receiving the radiated electric field radiated into the space from the portable electric field communication device is provided, the stray capacitance on the communication path is increased, the impedance is decreased, The signal strength can be increased.

  The electric field communication device for installation according to claim 2 is the electric field communication device for installation according to claim 1, wherein the auxiliary electrode is arranged adjacent to the communication electrode or arranged to surround the communication electrode. It is characterized by that.

  The electric field communication device for installation according to claim 3 is the electric field communication device for installation according to claim 2, wherein the communication electrode is disposed on a floor of a passage through which the electric field transmission medium passes, and the auxiliary electrode is It is arrange | positioned adjacent to the said communication electrode on the side surface of a passage.

  5. The electric field communication device for installation according to claim 4, wherein the communication electrode is disposed on a door knob of a door through which the electric field transmission medium passes, and the auxiliary electrode is connected to the door knob. It is arrange | positioned adjacent to the said communication electrode on the door surface of the side.

  The electric field communication device for installation according to claim 5 is the electric field communication device for installation according to claim 4, wherein the auxiliary electrode is two auxiliary electrodes arranged so as to sandwich the door knob.

  The electric field communication device for installation according to claim 6 is the electric field communication device for installation according to any one of claims 1 to 5, wherein the portable electric field communication device has two different polarities based on information to be transmitted. It is characterized by further comprising a demodulating means for outputting a signal and demodulating information to be received from the difference signal between the two signals.

  According to the present invention, the signal strength can be increased.

It is a figure which shows the utilization form of the electric field communication apparatus which concerns on 1st Embodiment. It is a figure which shows the functional block structure of the electric field communication apparatus for installation. It is a figure which shows the characteristic of this invention roughly. It is a figure which shows the utilization form of the electric field communication apparatus which concerns on 2nd Embodiment. It is a figure which shows the utilization form of the electric field communication apparatus which concerns on 3rd Embodiment. It is a graph which shows the effect of an auxiliary electrode. It is a figure which shows the utilization form of a general electric field communication apparatus. It is a figure which shows the structure of a portable electric field communication apparatus. It is a figure which shows the structure of the electric field communication apparatus for installation. It is a figure which shows the capacitive coupling model of an electric field communication apparatus.

  Hereinafter, an embodiment for carrying out the present invention will be described with reference to the drawings. However, the present invention can be implemented in many different modes and should not be construed as being limited to the description of the present embodiment.

[First Embodiment]
FIG. 1 is a diagram illustrating a usage pattern of the electric field communication device according to the first embodiment. This electric field communication device includes an electric field communication device 100 for installation installed around a passageway through which a person H as an electric field transmission medium passes, and a portable electric field communication device 300 possessed (provided) by the person H. Is done.

  First, the configuration and function of the installation electric field communication apparatus 100 will be described.

  The electric field communication device for installation 100 can perform electric field communication by inducing an electric field in an electric field transmission medium. As shown in FIGS. 1 and 2, the communication electrode 11, the auxiliary electrode 11 ′, The signal reception unit 20, the second signal reception unit 21, the differential amplification unit 22, and the demodulation unit 23 are mainly configured. Each part shown in FIG. 2 is configured by an electric circuit in which electric elements such as a resistor, an inductor, a capacitor, a switch, a diode, and a transistor are connected by an electric conductor.

  The communication electrode 11 is arranged on the floor of the passageway through which the person H passes, and is output from the portable electric field communication device 300 possessed by the person H when contacted by the human body H as the electric field transmission medium. The polarity signal is received by the electric field through the person H. The communication electrode 11 corresponds to the second electrode 11 shown in FIG.

  The auxiliary electrode 11 ′ is disposed adjacent to the communication electrode 11 on the side surface (wall surface) of the passage, and receives the radiated electric field radiated from the portable electric field communication device 300 to the space, and the portable electric field communication device 300. The other polarity signal output from is received by the electric field.

  As shown in FIG. 1, the auxiliary electrode 11 ′ is preferably disposed at a height close to or at the same height as the possessed position of the portable electric field communication device 300. Thereby, since the distance between the portable electric field communication device 300 and the auxiliary electrode 11 ′ can be close, the stray capacitance C1 on the communication path shown in FIG. 10 further increases, and the signal from the portable electric field communication device 300 is increased. Strength can be increased reliably.

  Further, in consideration of the arbitrary nature of the place where the portable electric field communication device 300 is carried, such as the front pocket and the rear pocket, two people H are sandwiched when the person H stands and contacts the communication electrode 11. The auxiliary electrode may be disposed on the side surface. Furthermore, the area of the auxiliary electrode 11 ′ may be increased by arranging it in the entire region instead of in one region of the side surface. As a result, the stray capacitance C1 is further increased, and the signal intensity from the portable electric field communication device 300 can be more reliably increased.

  The first signal receiving unit 20 is electrically connected to the communication electrode 11 through a connection cable, and receives a signal of one polarity received by the communication electrode 11.

  The second signal receiving unit 21 is electrically connected to the auxiliary electrode 11 ′ through a connection cable, and receives the radiated electric field and the signal of the other polarity received by the auxiliary electrode 11 ′. These signals having different polarities are 180 degrees out of phase with each other.

  The differential amplifier 22 takes a difference between two signals having different polarities respectively received by the first signal receiver 20 and the second signal receiver 21 and amplifies the signal of the difference.

  The demodulator 23 demodulates information (hereinafter referred to as data) to be received from the difference signal amplified by the differential amplifier 22, and transmits the demodulated information to the CPU 13 shown in FIG. The demodulator 23 corresponds to the signal processing circuit 162 shown in FIG.

  The configuration and the like of the installation electric field communication apparatus 100 have been described above. Note that the installation electric field communication apparatus 100 also includes a transmission circuit 15 that transmits a signal using an electric field, as shown in FIG. 9, but the description thereof in this embodiment is omitted. In addition, the electric field communication processing technology for receiving these two signals by the electric field using the radiated electric field received by the auxiliary electrode 11 ′ is the same as that described in the background art and Patent Document 1, and thus described. Is omitted.

  Next, the configuration and function of the portable electric field communication device 300 will be described.

  The portable electric field communication device 300 can perform electric field communication by inducing an electric field from an electrode to the electric field transmission medium. As shown in FIG. 8, the first electric field 32 that induces an electric field in the electric field transmission medium, The second electrode 33 is disposed on the opposing surface of the casing forming the outer shape of the portable electric field communication device 300, and the electric field based on the data is transmitted to the electric field transmission medium such as a human body by the transceiver circuit 31 stored inside. And output from the first electrode 32 and the second electrode 33 as two signals having different polarities.

  The configuration of the portable electric field communication device 300 has been described above. Note that the electric field communication processing technique by the transceiver circuit 31 is the same as that described in Patent Document 1, and thus the description thereof is omitted.

  Subsequently, the overall operation of the installation electric field communication apparatus 100 and the portable electric field communication apparatus 300 having such functions will be described. However, it is assumed that the first electrode 32 of the portable electric field communication device 300 faces toward the space and the second electrode 33 faces toward the human body.

  The portable electric field communication device 300 outputs a positive polarity signal and a negative polarity signal based on data modulated at a predetermined frequency from the first electrode 32 and the second electrode 33 arranged to face each other. . Moreover, as shown in FIG. 3, the radiation electric field is radiated | emitted from the 1st electrode 32 in space.

  At this time, when the person H touches the communication electrode 11, the radiated electric field radiated from the portable electric field communication device 300 is received by the auxiliary electrode 11 ′ of the installation electric field communication device 100. Can perform electric field communication with the portable electric field communication apparatus 300.

  Thereby, the negative signal output from the second electrode 33 of the portable electric field communication device 300 via the person H as the electric field transmission medium and the communication electrode 11 is the first electric field communication device 100 for installation. A positive signal received by the signal receiving unit 20 and output from the first electrode 32 via the auxiliary electrode 11 ′ is received by the second signal receiving unit 21.

  Thereafter, the differential amplifier 22 obtains and amplifies the difference between the positive signal and the negative signal received by the first signal receiver 20 and the second signal receiver 21, respectively.

  Finally, the demodulator 23 demodulates the data from the amplified difference signal and transmits it to the CPU 13.

  Note that the CPU 13 authenticates, for example, using identification information in the transmitted data, and determines whether or not permission is permitted for the passage (determined to be permitted if authentication is successful, and not permitted if authentication is unsuccessful). In the case of permission, a permission signal is output to a gate mechanism or the like installed in a passage or a door knob. In case of permission, a permission signal is output. Thereby, passability of passers passing through the passage is controlled.

  That is, according to the present embodiment, the installation electric field communication device 100 includes the auxiliary electrode 11 ′ that receives the radiated electric field radiated from the portable electric field communication device 300 to the space. The signal strength from the portable electric field communication device 300 can be increased.

[Second Embodiment]
FIG. 4 is a diagram illustrating a usage pattern of the electric field communication device according to the second embodiment. Instead of disposing the auxiliary electrode 11 ′ of the installation electric field communication device 100 on the side surface (wall surface) of the passage, it is disposed so as to surround the communication electrode 11 disposed on the floor of the passage with the gap G interposed therebetween. doing. Other configurations are the same as those of the first embodiment.

  Although the communication electrode 11 has an elliptical shape, it may be a perfect circle, a rectangle, a square, a rhombus, a trapezoid, or the like, and the shape of the electrode is not limited at all. The auxiliary electrode 11 ′ has a donut shape, but may be any shape that surrounds the communication electrode 11.

  Even in the present embodiment, since the installation electric field communication device 100 includes the auxiliary electrode 11 ′ that receives the radiated electric field radiated into the space from the portable electric field communication device 300, the floating electric field communication device 100 is floating. The capacity increases, and the signal strength from the portable electric field communication device 300 can be increased.

  Moreover, according to this Embodiment, since the communication electrode 11 and auxiliary electrode 11 'are arrange | positioned on the same surface (on the same channel | path), two electrodes can be installed easily.

[Third Embodiment]
FIG. 5 is a diagram illustrating a usage pattern of the electric field communication device according to the third embodiment. Instead of arranging the communication electrode 11 of the installation electric field communication device 100 on the floor of the passage, the communication electrode 11 is arranged on the doorknob of the door through which the person H as the electric field transmission medium passes.

  Further, the auxiliary electrode 11 ′ is arranged on the door surface on the door knob side adjacent to the communication electrode 11 ′ instead of being arranged on the floor or side surface (wall surface) of the passage.

  Even in the present embodiment, since the installation electric field communication device 100 includes the auxiliary electrode 11 ′ that receives the radiated electric field radiated into the space from the portable electric field communication device 300, the floating electric field communication device 100 is floating. The capacity increases, and the signal strength from the portable electric field communication device 300 can be increased.

  Note that the two auxiliary electrodes 11 ′ may be arranged so as to sandwich the door knob in consideration of the arbitrary location where the portable electric field communication device 300 is carried. In that case, you may arrange | position to the right and left of a doorknob, and may arrange | position to upper and lower sides.

  Further, as described in the second embodiment, one donut-shaped auxiliary electrode 11 ′ may be arranged on the door surface so as to surround the communication electrode 11 arranged on the door knob. The shapes of the communication electrode 11 and the auxiliary electrode 11 'are not limited at all.

  Finally, the effect of the auxiliary electrode 11 ′ described in the first to third embodiments will be described. FIG. 6 shows the received signal strength in the installation electric field communication apparatus 100 with respect to the change in the stray capacitance C1 on the communication path.

  As a result of the experiment, when there was no auxiliary electrode 11 ', the stray capacitance C1 on the communication path was about 0.01 to 0.1 pF. On the other hand, when the auxiliary electrode 11 ′ is present, it is about 0.6 to 8 pF. From this experimental result, it can be understood that the signal intensity is enhanced by about 15 dB (six times) by providing the auxiliary electrode 11 ′.

DESCRIPTION OF SYMBOLS 100 ... Electric field communication apparatus for installation 10 ... 1st electrode 11 ... 2nd communication, communication electrode 11 '... Auxiliary electrode 13 ... CPU
DESCRIPTION OF SYMBOLS 14 ... I / O circuit 15 ... Transmission circuit 16 ... Reception circuit 161 ... Electric field detection circuit 162 ... Signal processing circuit 17 ... Waveform shaping circuit 20 ... 1st signal receiving part 21 ... 2nd signal receiving part 22 ... Differential amplification part 23 ... demodulator 300 ... portable electric field communication device 31 ... transceiver circuit 32 ... first electrode 33 ... second electrode C1 ... stray capacitance G ... gap H ... human body

Claims (6)

In an electric field communication device for installation capable of performing electric field communication by inducing an electric field in an electric field transmission medium,
A communication electrode for receiving a signal transmitted from the portable electric field communication device provided in the electric field transmission medium by an electric field via the electric field transmission medium;
An auxiliary electrode that receives a radiated electric field radiated into the space from the portable electric field communication device;
An electric field communication device for installation characterized by comprising: The auxiliary electrode is
2. The electric field communication device for installation according to claim 1, wherein the electric field communication device for installation is disposed adjacent to the communication electrode or disposed so as to surround the communication electrode. The communication electrode is disposed on a floor of a passage through which the electric field transmission medium passes;
3. The installation electric field communication device according to claim 2, wherein the auxiliary electrode is disposed adjacent to the communication electrode on a side surface of the passage. The communication electrode is disposed on a door knob of a door through which the electric field transmission medium passes,
3. The installation electric field communication device according to claim 2, wherein the auxiliary electrode is disposed adjacent to the communication electrode on a door surface on the door knob side. The auxiliary electrode is
5. The installation electric field communication device according to claim 4, wherein the two auxiliary electrodes are arranged so as to sandwich the door knob. The portable electric field communication device outputs two signals having different polarities based on information to be transmitted,
6. The installation electric field communication apparatus according to claim 1, further comprising demodulation means for demodulating information to be received from a difference signal between the two signals.

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