JP2009239716A - Belt for electric field communication - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve communication quality of electric field communication and to make a communication state of the electric field communication stabler. <P>SOLUTION: A belt for electric field communication that can perform electric field communication by inducing an electric field in an electric field transmission medium from an electrode has a communication electrode for electric field communication provided on an inner surface of a buckle, and a ground electrode for electric field communication provided in a lining area from a belt hole to the tip of the belt, so the communication quality of electric field communication is improved and the communication state of electric field communication is made stabler. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a technique for improving communication quality of an electric field communication apparatus that performs communication by inducing an electric field in an electric field transmission medium.

  2. Description of the Related Art Conventionally, there has been proposed an electric field communication apparatus that induces an electric field based on data to be transmitted to an electric field transmission medium that transmits an electric field and performs data communication by detecting the electric field induced in the electric field transmission medium (patent) Reference 1).

  The conventional electric field communication device has a card shape as shown in FIG. 9 in order to facilitate connection to a card slot included in the information terminal. In the electric field communication device, in the slot-in state, the communication electrode 30 for transmitting and receiving data is disposed at the lower portion, and the ground electrode 50 for removing noise and the like is disposed at the upper portion. The communication circuit 20 that induces an electric field in the electric field transmission medium via the communication electrode 30 is arranged on the circuit board provided between the two.

Even in the case of a portable electric field communication device that can be carried by humans, an electric field is induced in a human body as an electric field transmission medium using a card-type electric field communication device similar to the shape shown in FIG. Data was transmitted and received by detecting an induced electric field transmitted.
JP 2003-324395 A

  However, in the case of such a card-type electric field communication device, since the distance between the communication electrode and the ground electrode (interelectrode gap) is very narrow, unnecessary electromagnetic waves generated in the communication circuit output from the ground electrode or There is a problem in that an electric field having an opposite phase is mixed into the communication electrode or the electric field transmission medium, and the force that the electric field induced from the communication electrode is coupled to the electric field transmission medium becomes weak.

  In addition, when a person has such a card-type portable electric field communication device, there is also a problem that the communication quality is not stable because the distance between the communication electrode and the human body changes depending on the operation state of the person. .

  This invention is made | formed in view of the above, and makes it a subject to improve the communication quality of electric field communication, and to stabilize the communication state of electric field communication more.

  The present invention according to claim 1 is an electric field communication belt capable of performing electric field communication by inducing an electric field from an electrode into an electric field transmission medium, and a communication electrode for electric field communication provided on an inner surface of a buckle. And a ground electrode for electric field communication provided in a surface area extending from the belt hole to the tip of the belt.

  In the present invention, an electric field communication belt capable of performing electric field communication by inducing an electric field from an electrode into an electric field transmission medium, the communication electrode for electric field communication provided on the inner surface of the buckle, and the belt hole Since it has the ground electrode for electric field communication provided in the surface covering area | region from the belt to the front-end | tip of a belt, the communication quality of electric field communication can be improved and the communication state of electric field communication can be stabilized more.

  That is, since the belt is usually used in a state of being wrapped around the waist and tightened, by providing the communication electrode on the inner surface of the buckle, the communication electrode can be brought close to the human body as an electric field transmission medium. The induced electric field can be more reliably induced in the human body. Therefore, the communication state of electric field communication can be further stabilized.

  In addition, by providing the ground electrode in the surface area from the belt hole to the tip of the belt, the distance between the communication electrode and the ground electrode can be secured at least twice the thickness of the belt. It is possible to prevent unnecessary electromagnetic waves generated in the output communication circuit and electric fields having opposite phases from being mixed into the communication electrode. Therefore, the communication quality of electric field communication can be improved.

  The gist of the present invention described in claim 2 is that the distance between the communication electrode and the ground electrode is at least 10 mm when the electric field communication belt is fastened.

  ADVANTAGE OF THE INVENTION According to this invention, the communication quality of electric field communication can be improved and the communication state of electric field communication can be stabilized more.

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

  FIG. 1 is a configuration diagram showing the configuration of the electric field communication belt in the present embodiment. The electric field communication belt includes a portable electric field communication device 10 having a communication circuit for inducing an electric field from the communication electrode 30 to an electric field transmission medium, and an electric field communication communication electrode provided on an inner surface of a buckle (fastener). 30 and a ground electrode 50 for electric field communication provided in a surface tension region from the belt hole to the tip of the belt. In addition, although illustration is abbreviate | omitted, the portable electric field communication apparatus 10 and the communication electrode 30 can be electrically connected, and the portable electric field communication apparatus 10 and the ground electrode 50 can be electrically connected. Lead wires are also provided.

  FIG. 2 is a cross-sectional view of the electric field communication belt shown in FIG. 1 as it is wound from around the waist of the human body as an electric field transmission medium and viewed from above. As shown in the figure, by providing the communication electrode 30 on the inner surface of the buckle, the communication electrode 30 can be brought close to the human body as the electric field transmission medium 70, so that the electric field induced from the communication electrode 30 is more reliably generated. It can be induced in the human body. Further, by providing the ground electrode 50 in the surface area from the belt hole to the tip of the belt, it is possible to secure at least twice the gap between the communication electrode 30 and the ground electrode 50 (interelectrode gap) as much as the thickness of the belt. Therefore, it is possible to prevent unnecessary electromagnetic waves generated in the communication circuit 20 output from the ground electrode 50 and electric fields having opposite phases from being mixed into the communication electrode 30 and the electric field transmission medium 70.

  Next, the operation of the communication electrode 30 will be described. FIG. 3 is a block diagram illustrating an example of a circuit configuration of an electric field communication device that performs electric field communication using the communication electrode 30. As shown in FIG. 3, the communication circuit 20 that connects the information terminal 15 and the communication electrode 30 is connected to the information terminal 15 via the interface circuit 21. When the communication circuit 20 receives transmission data for transmission from the information terminal 15 to another information terminal 15 via the interface circuit 21, the communication circuit 20 adjusts the signal amplitude of the transmission data by the level adjustment circuit 22, and then transmits the transmission circuit. 23 to supply to the transmission electrode 30a.

  When transmission data is supplied from the transmission circuit 23, the transmission electrode 30 a induces an electric field corresponding to the transmission data in the electric field transmission medium 70. The induced electric field is transmitted through the electric field transmission medium 70 and received by the receiving electrode 30b of the electric field communication device in the other information terminal 15.

  The electric field detection optical unit 24 is supplied with the electric field received by the reception electrode 30b, changes the polarization of laser light separately generated in the electric field detection optical unit 24 using the electric field optical technique, and converts it into an electric signal. This electric signal is supplied with the information terminal 15 via the interface circuit 21 after unnecessary noise is removed by the band limitation in the signal processing circuit 25 and the waveform is further shaped by the waveform shaping circuit 26. ing.

  Note that the transmission electrode 30a and the reception electrode 30b may be integrated to form each electrode with one communication electrode 30, but may have only one configuration of transmission or reception.

  Here, the ground electrode 50 shown in FIG. 2 is provided in the electric field detection optical unit 24 described with reference to FIG. FIG. 4 is a block diagram showing a configuration of the electric field detection optical unit 24 used in the communication circuit 20 shown in FIG. The electric field detection optical unit 24 detects an electric field by an electro-optic technique using laser light and an electro-optic crystal, and includes a laser diode 101 that constitutes a laser light source and an electro-optic element 102 made of an electro-optic crystal. The electro-optical element 102 is sensitive to an electric field coupled in a direction perpendicular to the traveling direction of the laser light from the laser diode 101, and the optical characteristics, that is, the birefringence changes depending on the electric strength. The polarization of the laser beam is changed by the change of the birefringence.

  A first electrode 103 and a second electrode 104 are provided on both side surfaces of the electro-optic element 102 facing in the vertical direction in the drawing. The first electrode 103 and the second electrode 104 sandwich the traveling direction of the laser light from the laser diode 101 in the electro-optic element 102 from both sides, and couple the electric field at right angles to the laser light. Yes.

  The electric field detection optical unit 24 illustrated in FIG. 4 includes the same communication electrode 30 as illustrated in FIG. 2 or 3, and the communication electrode 30 is connected to the first electrode 103. Also, the second electrode 104 facing the first electrode 103 is connected to the same ground electrode 50 as shown in FIG. 2 and is configured to function as a ground electrode with respect to the first electrode 103. That is, the ground electrode 50 is provided in order to release unnecessary electromagnetic waves generated in the communication circuit 20 or an anti-phase electric field to the outside to improve the quality of electric field communication. When the communication electrode 30 detects the electric field transmitted by being induced in the electric field transmission medium, the communication electrode 30 transmits the electric field to the first electrode 103 and is coupled to the electro-optic element 102 via the first electrode 103. Yes.

  The laser light output from the laser diode 101 is converted into parallel light through the collimator lens 105, and the laser light that has become parallel light is adjusted in polarization state by the first wave plate 106 and enters the electro-optical element 102. The laser light incident on the electro-optic element 102 propagates between the first electrode 103 and the second electrode 104 in the electro-optic element 102. During the propagation of the laser light, the communication electrode 30 generates an electric field as described above. When an electric field induced and transmitted by the transmission medium is received and this electric field is coupled to the electro-optic element 102 via the first electrode 103, the electric field is connected to the ground electrode 50 from the first electrode 103. Since it is formed toward the electrode 104 and is perpendicular to the traveling direction of the laser light incident on the electro-optic element 102 from the laser diode 101, the birefringence, which is the optical characteristic of the electro-optic element 102, is changed. The polarization of light changes.

  In this way, the laser light whose polarization has been changed by the electric field from the first electrode 103 in the electro-optic element 102 is adjusted in polarization state by the second wavelength plate 107 and enters the polarization beam splitter 108. The polarization beam splitter 108 separates the laser light incident from the second wavelength plate 107 into P waves and S waves, and converts them into changes in light intensity. The laser light separated into the P wave component and the S wave component by the polarization beam splitter 108 is condensed by the first condenser lens 109a and the second condenser lens 109b, respectively, and then the first photodiode 110a and the second photodiode 110a. The first and second photodiodes 110a and 110b are supplied to the photodiode 110b and convert the P-wave optical signal and the S-wave optical signal into respective electric signals and output them.

  As described above, the electric signals output from the first photodiode 110a and the second photodiode 110b are subjected to signal processing such as amplification and noise removal in the signal processing circuit 25 shown in FIG. Then, the waveform is shaped and supplied to the information terminal 15 via the interface circuit 21.

  FIG. 5 is a block diagram illustrating another example of a circuit configuration of an electric field communication device that performs electric field communication using the communication electrode 30. In the block diagram shown in FIG. 5, the communication circuit 20 to which the information terminal 15 is connected, the electric field transmission medium 70 for mediating communication, the communication circuit 20 ′, and the information terminal 15 ′ connected to the communication circuit 20 ′. Is shown. A case where communication is performed between the communication circuit 20 and the communication circuit 20 ′, data is transmitted from the communication circuit 20 and received by the communication circuit 20 ′ is taken as an example.

  The communication circuit 20 and the communication circuit 20 'have the same configuration. Although there is no difference in configuration between the two, for convenience of explanation, the same number is assigned to the same component, and the component provided in the communication circuit 20 ′ is identified with “′”. Yes.

  The information terminal 15 sends transmission data and a transmission / reception switching signal to the communication circuit 20. The transmission data is arbitrary data transmitted to the communication terminal information terminal 15 '. The transmission / reception switching signal is a signal for instructing the communication circuit 20 to switch operation between transmission and reception.

  Further, the communication circuit 20 sends received data to the information terminal 15. This reception data is reception data obtained by receiving data transmitted from the communication terminal information terminal 15 ′ to the information terminal 15 via the communication circuit 20 ′ and the communication circuit 20. Note that transmission data, transmission / reception switching signals, and reception data are exchanged between the information terminal 15 ′ and the communication circuit 20 ′ as well as between the information terminal 15 and the communication circuit 20.

  Further, the communication circuit 20 includes a transmission unit for transmitting data and a reception unit for receiving data. The transmission unit includes a modulation circuit 40 for modulating transmission data with a carrier wave output from the oscillator 41 and an oscillator 41 for outputting the carrier wave. Further, the receiving unit includes a correction circuit 42 for determining and correcting whether the H level and the L level of the demodulated signal are inverted, a carrier wave reproduced by the carrier wave reproducing circuit 44, and the received signal. And a demodulating circuit 43 for reproducing data and a carrier wave reproducing circuit 44 for extracting a carrier wave from the received signal.

  In addition, the communication electrode 30 receives the data transmitted from the communication circuit 20 ′ and the function of transmitting the data transmitted from the communication circuit 20 to the communication circuit 20 ′, as in the case described with reference to FIG. It has a function. Even in the case of the electric field communication apparatus having the communication circuit 20 shown in FIG. 5, the transmission electrode 30a and the reception electrode 30b may be integrated to form each electrode by one communication electrode 30, or transmission or reception may be performed. It is good also as what has only any one structure.

  FIG. 6 shows a configuration diagram for explaining the configuration of the correction circuit 42 and the correction circuit 42 ′ shown in FIG. 5. The communication circuit 20 and the communication circuit 20 ′ shown in FIG. 5 are provided with a correction circuit 42 and a correction circuit 42 ′ for the purpose of preventing inversion of the H level and the L level at the output of the reception unit. ing. Since the correction circuit 42 of the communication circuit 20 and the correction circuit 42 'of the communication circuit 20' are the same, only the correction circuit 42 'included in the communication circuit 20' will be described here.

  The correction circuit 42 'has an inversion / non-inversion switching circuit 61 for inverting the signal when the H level and L level of the demodulated signal are inverted, and the H level and L level of the demodulated signal are inverted. A sampling circuit 62 for determining whether or not there is a switching signal, a detector 63 for detecting a reproduced carrier wave and generating a sampling signal, and until the determination of the H level and L level of the demodulated signal can be sufficiently distinguished And a delay unit 64 for delaying the sampling signal.

  Here, the ground electrode 50 shown in FIG. 2 is connected to the modulation circuit 40 and the demodulation circuit 43 described with reference to FIG. FIG. 7 is a configuration diagram showing a connection configuration between the modulation circuit 40 and the ground electrode 50. The modulation circuit 40 is connected to the communication electrode 30 including the transmission electrode 30a and the reception electrode 30b, and to the ground electrode 50 having the function described with reference to FIG. The ground electrode 50 connected to the modulation circuit 40 functions during data transmission, and the ground electrode 50 connected to the demodulation circuit 43 functions during data reception. One ground electrode 50 may be connected to the modulation circuit 40 and the demodulation circuit 43, or a different ground electrode 50 may be connected to each circuit.

Subsequently, measurement results of communication performance in the electric field communication belt in the present embodiment described with reference to FIGS. 1 to 7 and the conventional electric field communication device described in FIG. 9 will be described. As shown in FIG. 8A, the measurement of the communication performance of the electric field communication belt is carried out by placing a human body as an electric field transmission medium 70 around which the electric field communication belt is wound and fastened on the floor electrode 130. It is assumed that the intensity of the signal transmitted from the electric field communication belt is measured using the spectrum analyzer 90 connected to the electrode 130. The electrode area of the communication electrode 30 is 18 [cm ² ] (= vertical width 3.0 [cm] × horizontal width 6.0 [cm]), and the electrode area of the ground electrode 50 is the same. The width of the belt is 3 [cm] and the thickness is about 5 [mm]. Therefore, when the belt is fastened, the inter-electrode gap between the communication electrode 30 and the ground electrode 50 is about 10 [mm] (corresponding to about twice the thickness of the belt).

On the other hand, the communication performance of the conventional electric field communication device is measured by placing a human body as an electric field transmission medium 70 in which the conventional electric field communication device is placed in a breast pocket on the floor electrode 130 as shown in FIG. Then, the intensity of the signal transmitted from the electric field communication device is measured using the spectrum analyzer 90 connected to the floor electrode 130. Further, the electrode area of the communication electrode is 18 [cm ² ] (= vertical width 4.5 [cm] × horizontal width 4.0 [cm]), similar to the electrode area of the communication electrode 30 of the electric field communication belt. The electrode area of the ground electrode is the same. The interelectrode gap shown in FIG. 9 is 4 [mm].

  The signal strength in the electric field communication belt obtained under the measurement conditions as described above was -57.8 [dBm], and the signal strength in the conventional electric field communication device was -62.3 [dBm]. . From this measurement result, the electric field communication belt in the present embodiment has a signal strength of +4.5 [dBm] higher than that of the conventional electric field communication device, so that the communication quality of the electric field communication is improved and the electric field communication is improved. The communication state can be further stabilized.

  The electric field communication belt having such an effect is used in a processing system that needs to transmit and receive data with high reliability. For example, application to JR (abbreviation of Japan Reilway) and subway ticket gates is a suitable example. Specifically, the electric field communication belt includes, in addition to the configuration described in this embodiment, a storage unit that stores an ID for identifying a user who owns the electric field communication belt, and a human body. And a transmission unit that transmits the ID stored in the storage unit from the communication electrode 30 described above. The ticket gate electric field communication apparatus includes a storage unit that stores a plurality of IDs registered in advance, a reception unit that receives IDs via reception electrodes arranged in a passage provided with a gate, and FIG. Alternatively, the communication circuit 20 described with reference to FIG. 5, the authentication unit that authenticates whether the received ID matches the plurality of IDs stored in the storage unit, and the plurality of received IDs stored in the storage unit. And a control unit that opens the gate in the case of matching with the ID (in the case of authentication OK). When a user who has tightened the electric field communication belt passes the ticket gate, the ID transmitted from the communication electrode 30 of the electric field communication belt via the user is the reception electrode of the electric field communication device for ticket gate. If the authentication with the ID received and stored in the storage unit is OK, the gate is opened.

  Many office workers and students use the train as a means of transportation, but if the PASMO (Supa) or Suica (watermelon) as a non-contact medium trapped at the ticket gate is not recognized well, the gate will close and the following people will be There is a possibility that homes are mixed depending on the timing. In such a case, by using the above-mentioned electric field communication belt, the reliability of communication between the electric field communication belt and the electric field communication device for ticket gates is increased, so that traffic congestion at the ticket gates can be more reliably alleviated. It becomes possible.

  According to the present embodiment, in the electric field communication belt capable of performing electric field communication by inducing an electric field from the electrode in the electric field transmission medium, the communication electrode 30 for electric field communication provided on the inner surface of the buckle; Since it has the ground electrode 50 for electric field communication provided in the surface area from the belt hole to the tip of the belt, the communication quality of electric field communication can be improved and the communication state of electric field communication can be further stabilized. .

It is a block diagram which shows the structure of the electric field communication belt in this Embodiment. It is sectional drawing at the time of seeing the state which wound the belt for electric field communication shown in FIG. 1 around the waist | hip | lumbar of the human body as an electric field transmission medium, and was tightened. It is a block diagram which shows an example of the circuit structure of the electric field communication apparatus which performs electric field communication using a communication electrode. It is a block diagram which shows the structure of the electric field detection optical part used for the communication circuit shown in FIG. It is a block diagram which shows another example of the circuit structure of the electric field communication apparatus which performs electric field communication using a communication electrode. It is a block diagram for demonstrating the structure of the correction circuit shown in FIG. It is a block diagram which shows the connection structure of a modulation circuit and a ground electrode. It is explanatory drawing for demonstrating the measurement structure of the communication performance in the electric field communication belt in this Embodiment, and the conventional electric field communication apparatus. It is sectional drawing which shows the cross section of the conventional electric field communication apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Portable electric field communication apparatus 15 ... Information terminal 20 ... Communication circuit 21 ... Interface circuit 22 ... Level adjustment circuit 23 ... Transmission circuit 24 ... Electric field detection optical part 25 ... Signal processing circuit 26 ... Waveform shaping circuit 30 ... Communication electrode 30a ... Transmission electrode 30b ... Reception electrode 40 ... Modulation circuit 41 ... Oscillator 42 ... Correction circuit 43 ... Demodulation circuit 44 ... Carrier wave recovery circuit 50 ... Ground electrode 61 ... Inversion / non-inversion switching circuit 62 ... Sampling circuit 63 ... Detector 64 ... Delay device DESCRIPTION OF SYMBOLS 70 ... Electric field transmission medium 90 ... Spectrum analyzer 101 ... Laser diode 102 ... Electro-optic element 103 ... 1st electrode 104 ... 2nd electrode 105 ... Collimating lens 106 ... 1st wavelength plate 107 ... 2nd wavelength plate 108 ... Polarizing beam splitter 109a ... first condenser lens 109b ... second condenser lens 110a ... 1st photodiode 110b ... 2nd photodiode 130 ... Floor electrode

Claims (2)

In an electric field communication belt capable of performing electric field communication by inducing an electric field from an electrode into an electric field transmission medium,
A communication electrode for electric field communication provided on the inner surface of the buckle;
A ground electrode for electric field communication provided in a surface area from the belt hole to the tip of the belt;
An electric field communication belt comprising:   2. The electric field communication belt according to claim 1, wherein an interval between the communication electrode and the ground electrode is at least 10 mm when the electric field communication belt is fastened.

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