Communication system

Communication Systems

Technical field

The present invention relates to a communication system and is preferably applicable to, for example, a communication system for transmitting and receiving information via an electric field.

Background technique

In general, communication systems have been adapted to use radiation fields (radio waves) to send and receive information between mobile phones, for example, as well as coils in data readers/writers on ticket inspection and ticket collectors provided at stations. It sends and receives information via electromagnetic induction with the coil in the IC card.

Recently, the following communication system has been proposed, which has a human-side communication device installed in contact with the human skin and an equipment-side communication device near the user, as shown in Table 1 below. In these communication systems, an AC voltage is applied to the human body via the electrodes of the human-side communication device. As a result, the device uses a capacitor that intervenes the human body as a medium between the electrodes of the human-side communication device and the equipment-side communication device. Electrostatic induction phenomenon is caused at the electrode of the side communication device. Using this electrostatic induction phenomenon, information is transmitted and received (for example, see Non-Patent Document 1).

Table 1

In addition to the communication systems shown in Table 1, there have also been proposed many communication systems suitable for transmitting and receiving information using the electrostatic induction phenomenon by using a capacitor that intervenes the human body between the transmitting electrode and the receiving electrode as a medium The effect is caused at the receiving electrode (see Patent Documents 1-9 and Non-Patent Documents 2-5).

[Patent Document 1] International Patent Application National Publication No. 11-509380 [Patent Document 2] Patent No. 3074644 [Patent Document 3] Japanese Patent Laid-Open No. 10-228524 [Patent Document 4] Japanese Patent Laid-Open No. 10-229357 [Patent Document 5] Japanese Patent Laid-Open No. 2001-308803 [Patent Document 6] Japanese Patent Laid-Open No. 2000-224083 [Patent Document 7] Japanese Patent Laid-Open No. 2001-223649 [Patent Document 8] Japanese Patent Laid-Open No. 2001-308803 [Patent Document 9] Japanese Patent Laid-Open No. 2002-9710 [Non-Patent Document 1] Internet <URL: http://www.mew.co.jp/press/0103/ 0103-7.htm>(Retrieved on January 20, 2003) [Non-Patent Document 2] "Development of Information Communication Device with Human Body Used as Transmission Line" by Keisuke Hachisuka, Anri Nakata, Kenji Shiba, Ken sasaki, Hiroshi Hosaka and Kiyoshi Itao (University of Tokyo); March 1, 2002 (Proceedings of Micromechatronics Academic Lectures, vol., 2002, Spring, pp.27-28) [Non-Patent Document 3] "Development of Communicaiton System within Organism (Bio Development of Intrabody Communication System" Authors Anrinakata, Keisuke Hachisuka, Kenji Shiba, Ken Sasaki, Hiroshi Hosaka, Kiyoshi Itao (University of Tokyo); 2002 (Proceedings of Academic Lectures at the Japan Precision Engineering Conference, Spring, p.640) [Non-Patent Literature 4] "Review on Modeling of Communicaiton System Utilizing Human Body as Transmission Line", author Katsuyuki Fujii (Chiba University), Koichi Date (Chiba University), Shigeru Tajima (Sony Computer Science Laboratory, Co., Ltd.); March 1, 2002 (Science and Technology Report Vol.26, No.20, pp.13-18 of the School of Image Information and Visual Engineering) [Non-Patent Document 5] "Development of Information Communication Device with Human Body Used as Transmission Line" by Keisuka Hachisuka, Anri Nakata, KentoTakeda, Ken Sasaki, Hiroshi Hosaka, Kiyoshi Itao (University of Tokyo, new field creation scientific research College), Kenji Shiba (Science and Engineering Course, Tokyo University of Science (Tokyo Institute of Technology Polytechnic Course); March 18, 2002 (Micromechatronics, Vol.46; No.2; pp.53-64) In these communication systems with this configuration, due to the use of intervening transmission electrodes and The function of the capacitor that receives the human body between the electrodes as a medium is a prerequisite for the physical function, so the communication strength in the communication between the electrodes depends on the area of the electrodes.

In addition, since the use of a capacitor that intervenes the human body between the transmitting electrode and the receiving electrode as a medium is a prerequisite for physical action, for example, when the transmitting electrode is installed on the right wrist of a person, it is not necessary to move from the right wrist to the tip of the finger. It is physically impossible to communicate in directions outside of the direction. When the transmitting electrode is installed near a person's chest, communication in a direction other than the forward direction from the person's chest is physically impossible.

As described above, in the communication system, since the use of a capacitor that intervenes the human body between the transmitting electrode and the receiving electrode as a medium is a prerequisite for physical action, there is the following problem: the communication direction is limited by the position where the electrode is installed on the human body And since the communication intensity depends on the electrode area, the degree of freedom in communication is low.

Summary of the invention

The present invention is proposed in consideration of the above problems, and the present invention proposes a communication system, communication device, and communication method capable of enhancing the degree of freedom in communication.

In the present invention, in order to solve the above-mentioned problems, a communication system is configured to have a first communication device for electrification by generating a quasi-electrostatic field modulated according to the information to be transmitted. The identification target of the attribute is charged; and the second communication device is used to detect a change in the charged state of the identification target and demodulate the information based on the change.

In this case, in the communication system, the identification target can be used as an antenna in a quasi-electrostatic field isotropic from the surface of the identification target by charging the identification target according to specific information. Thus, communication can be performed under the condition that the communication direction is not restricted by the position of the electrode of the first communication device and under the condition that the communication intensity does not depend on the electrode area, and thus the degree of freedom in communication can be enhanced.

In the present invention, even when the identification target is a human body, the human body can be used as an antenna in an isotropic quasi-electrostatic field from the surface of the human body, regardless of whether the human body moves or not. This is because the nature of the human body makes the human body Well charged.

In addition, in the present invention, by forming an electrode having a structure according to the reference frequency so that the intensity of the induction field of the electric field is lower than the noise floor specified according to the communication frequency band, it is possible to reduce the induction field components and radiation unnecessary for communication with the electrostatic field. The field component reduces the energy required for communication, and can prevent unnecessary propagation to enhance the spatial resolution, which makes the communication stable. In this way, the communication can be stabilized.

As described above, according to the present invention, an identification target having a charging attribute is charged by generating a quasi-electrostatic field modulated according to the information to be transmitted, and information is demodulated based on a change in the charged state of the identification target, so that the The marking target is charged so that the marking target serves as an antenna in a quasi-electrostatic field isotropic from the surface of the marking target. Thus, communication can be performed under the condition that the communication direction is not restricted by the position of the transmitting-side electrode and under the condition that the communication intensity does not depend on the electrode area, and thus the degree of freedom in communication can be enhanced.

In addition, according to the present invention, even when the identification target is a human body, the human body can be used as an antenna in a quasi-electrostatic field isotropic from the surface of the human body regardless of the presence or absence of human motion, because the nature of the human body makes The human body is well charged. In this way, the degree of freedom in communication can be enhanced.

In addition, according to the present invention, by forming an electrode having a structure according to the reference frequency so that the intensity of the induction field of the electric field is lower than the noise floor specified according to the communication frequency band, it is possible to reduce the induction field components and radiation fields unnecessary for aligning electrostatic field communication. Components to reduce the energy required for communication, and can prevent unnecessary propagation to enhance the spatial resolution, which makes the communication stable. In this way, the communication can be stabilized and the degree of freedom in the communication can be enhanced.

Description of the drawings

Fig. 1 is a schematic diagram for explaining the polar coordinate system; Fig. 2 is a diagram showing the relative intensity change of each electric field with respect to the distance (1); Fig. 3 is a diagram showing the relative intensity change of each electric field with respect to the distance (2 4 is a diagram showing the relationship between wavelength and distance; FIG. 5 is a schematic diagram showing the overall configuration of the communication system according to the first embodiment; FIG. 6 is a diagram showing the ticket inspection and ticket collection machine Schematic/block diagram of the configuration;

7 is a schematic diagram for explaining the role of the human body as an antenna; FIG. 8 is a schematic diagram showing the electrical connection relationship in the communication system; FIG. 9 is a circuit block diagram showing the configuration of the card device; FIG. 10 is for explaining the test The base surface of the ticket and the ticket collector (floor Fig. 11 is a schematic diagram showing the equipotential surface of the quasi-electrostatic field formed when the human body is used as an ideal dipole antenna; Fig. 12 is a schematic diagram showing the equipotential surface of the quasi-electrostatic field formed according to this embodiment Fig. 13 is a schematic diagram for explaining the prevention of leakage; Fig. 14 is a schematic diagram showing an example of installing a card device in another embodiment; Fig. 15 is a schematic diagram showing the configuration of a noise absorption/grounding line; Fig. 16 Is a schematic diagram/block diagram showing the configuration (1) of the ticket inspection and ticket collection machine in another embodiment; FIG. 17 is a schematic diagram showing the electrical connection relationship (1) in the communication system in another embodiment; 18 is a circuit block diagram showing the configuration of a card device in another embodiment; FIG. 19 is a schematic diagram/block diagram showing the configuration (2) of a ticket inspection and ticket collector in another embodiment; FIG. 20 is a diagram showing Fig. 21 is a block diagram showing the configuration of a sound reproducer; Fig. 22 is a block diagram showing the configuration of a headset device; Fig. 23 is a block diagram showing the configuration of a headset device; A schematic diagram of an example of a human body model simulated by the FDTD method; FIG. 24 is a schematic diagram showing the relationship between the electrode area on the receiving side and the potential between electrodes; FIG. 25 is a diagram showing the relationship between the distance between electrodes on the receiving side and the potential between electrodes Figure 26 is a schematic diagram showing the relationship between the electrode area on the transmitting side and the potential between electrodes on the receiving side; Figure 27 is a schematic diagram showing the relationship between the distance between electrodes on the transmitting side and the potential between electrodes on the receiving side; 28 is a schematic diagram showing the relationship between the electric field strength of the combined electric field and the distance from the electric field source; FIG. 29 is a schematic diagram showing the relationship between the electric field strength of the induction field and the distance from the electric field source; A schematic diagram of the relationship between potential and frequency; and FIG. 31 is a flowchart showing the design process.

detailed description

The present invention will now be described in detail with reference to the drawings.

(1) Summary of the invention According to the present invention, an electric field is used to transmit and receive information. The outline of the present invention will now be described in terms of the relationship with the electric field.

(1-1) Electric field Normally, when current flows through an electric dipole (dipole antenna), the electric field E generated according to the distance r from the antenna can be given by the simplified formula shown below: E0=A(1r3+ jkr2+k2r1)...(1)]]> where A and j are constants, and k is the number of waves.

As shown in the above formula (1), the electric field E can be roughly divided into a component that is inversely proportional to the third power of the distance r (hereinafter, this component is referred to as a quasi-electrostatic field), and a component that is inversely proportional to the second power of the distance r (Hereinafter, this component is called the induction field), a component linearly inversely proportional to the distance r (hereinafter, this component is called the radiation field).

The radiation field is a component with superior propagation ability. Since it is only linearly inversely proportional to the distance r, it does not decay rapidly even when the distance r is long. Therefore, it has been used as a common information transmission medium in the field of information communication.

Although the induction field is a component with very weak propagation ability, it attenuates inversely proportional to the second power of the distance r when the distance r is lengthened, but it has recently been used as an information transmission medium in a part of the information communication field.

The quasi-electrostatic field is a component that decays rapidly in inverse proportion to the third power of the distance r, so it has no propagation ability and it only appears as a vibration near the vibration source. Therefore, it has not been used in the field of information communication where radiation field and induction field are the prerequisites.

The present invention is suitable for transmitting and receiving information in a nearby communication range using a proximity communication (hereinafter referred to as near field communication) method using a quasi-electrostatic field in an electric field.

(1-2) Quasi-electrostatic field The quasi-electrostatic field will now be described in more detail. First, as shown in FIG. 1, the electric field E shown in the above formula (1) is expressed as an electric field at a position P(r, θ, φ) at a predetermined distance from the origin.

In this case, if it is assumed that the charge q and the charge -q are separated from each other by a distance δ, and the charge q becomes "Qcosωt" at time t, the position of the charge q is taken as the origin, and the positions P(r, θ , Φ) The electric fields Er, Eθ, Eφ are expressed as the following formula: Er=Qcosωtσcosθ2πϵr3(1+jkr)exp(-jkr)]]>

Eθ=Qcosωtσsinθ2πϵr3(1+jkr+(jkr)2)exp(-jkr)]]>Eφ=0 ... (2) In formula (2), The electric field Eφ is "zero", and this means that no electric field is generated in the φ direction of the position P (Figure 1).

If the components linearly inversely proportional to the distance r (ie, the radiation field) are separated from the electric fields Er and Eθ expressed in formula (2), the radiation fields E1r and E1θ at the position P(r,θ,φ) are below The formula says: E1r=0E1θ=Qcosωtσsinθ4πϵr(jk)2exp(-jkr)...(3)]]>If the component is inversely proportional to the second power of the distance r (Ie, the induction field) is separated from the electric fields Er and Eθ expressed in formula (2), the induction fields E2r and E2θ at the position P(r,θ,φ) are expressed by the following formula: E2r=Qcosωtσcos&theta ;2πϵr2jk·exp(-jkr)]]>E2θ=Qcosωtσsinθ4πϵr2jk·exp(-jkr)...(4)]]>In addition, if the distance between The inversely proportional component of the third power of r (ie, the quasi-electrostatic field) is separated from the electric fields Er and Eθ expressed in formula (2), then the quasi-electrostatic fields E3r and E3θ at the position P(r, θ, φ) are as follows Formula: E3r=Qcosωtσcosθ2πϵr3]]>E3θ=Qcosωtσsinθ4πϵr3...(5)]]> In formula (3), only The radiation field E1r is "zero", which means that no radiation field is generated in the tangential direction of the position P (Figure 1).

Now, in order to show the components of the electric field strength of each of the radiation field, the induction field, and the quasi-electrostatic field at the distance r, the radiation field E1θ and the induction field E2θ in formulas (3) to (5) will now be described in more detail. And the quasi-electrostatic field E3θ.

The wave number k[m-1] conforms to the relationship shown in the following formula, where ω represents the angular frequency and c represents the speed of light: k=ωc...(6)]]> If the wave number k is substituted into the formula (6), Elimination of "j.exp(-jkr)" because it is beyond the scope of this article, and because the maximum time change between charge q and charge -q is to be considered, assuming that "cosωt" is one (1), the following can be obtained Formula: Radiation field E1θ=Qσsinθ4πϵr3(ωcr)2]]> induction field E2θ=Qσsinθ4πϵr3ωcr]]>quasi-electrostatic field E3θ =Qσsinθ4πϵr3...(7)]]>If the distance δ, charge q(=Q) and θ are substituted with one (1), 0.001[C] and π/2, respectively Reorganizing formula (7), the following formula is obtained: radiation field E1θ=0.0014πϵ0r(ωc)2]]> induction field E2θ=0.0014πϵ0r2ωc]]> Quasi-electrostatic field E3θ=0.0014πϵ0r3...(8)]]> Figures 2 and 3 show the qualitative drawing of radiation field E1θ, induction field E2θ, and quasi-electrostatic field E3θ based on formula (8). The result obtained by the component electric field strength.

However, in FIGS. 2 and 3, the component electric field intensity at a frequency of 1 [MHZ] is shown, and in FIG. 3, the index (index scale) shown in FIG. 2 is replaced by indexes (index scale). The component electric field strength.

It is particularly clear from Figure 3 that the component electric field strengths of the radiation field E1θ, the induced field E2θ, and the quasi-electrostatic field E3θ are equal at a certain distance r (hereinafter referred to as the boundary point), and are far away from the boundary point. The radiation field E1θ is dominant. On the contrary, in the vicinity before the boundary point, the quasi-electrostatic field E3θ is dominant.

At the boundary point, the following formula is established according to the above formula (8):

ωc·r=1...(9)]]>The speed of light c satisfies the relationship shown in the following formula, where λ represents the wavelength and f represents the frequency: c=λ·f ......(10) angle The frequency ω satisfies the relationship shown in the following formula: ω=2πf ......(11) Then, by substituting formula (10) and formula (11) into formula (9) and rearranging formula (9), we obtain The following formula: r=λ2π...(12)]]> According to formula (12), the distance r from the origin to the boundary point changes according to the wavelength λ. As shown in Fig. 4, the longer the wavelength λ, the wider the range in which the quasi-electrostatic field E3θ is dominant (the distance r from the origin to the boundary point).

Summarizing the above description, if the relative permittivity of air is assumed to be 1 and the wavelength in air is assumed to be λ, the quasi-electrostatic field E3θ dominates in the range where the distance r to the origin conforms to "r<λ/2π".

In the present invention, by selecting a range that satisfies the formula (12) when using the near field communication method to transmit and receive information, the information is transmitted and received in a space where the quasi-electrostatic field E3θ is dominant.

(1-3) Quasi-electrostatic field and human body Although it is necessary to apply current to the human body to generate a radiation field or an induction field, it is physically difficult to effectively apply current to the human body because the human body has a very high impedance. And physiologically, it is not desirable to apply electric current to the human body. However, for electrostatics, the situation is completely different.

That is, as shown by the empirical facts of feeling static electricity in our daily lives, the human body is often charged. As the well-known quasi-electrostatic field is generated by charging on the surface of the human body in response to the movement of the human body, there is no need to energize the human body to generate a quasi-electrostatic field, but it is necessary to charge the human body only.

That is, the human body is charged with very little electric charge movement (current); the charged change is instantly conducted around the surface of the human body; and the equipotential surface of the quasi-electrostatic field is basically formed isotropically from the surroundings. In addition, in the range where the above formula (12) is predominantly satisfied by the quasi-electrostatic field, the radiation field and the induction field do not have a great influence. As a result, the human body effectively functions as an antenna. This has been verified from the applicant's experimental results.

As a near field communication technology, this information is suitable for modulating a quasi-electrostatic field formed isotropically near the human body by charging the human body according to specific information, and as a result of the modulation, a quasi-electrostatic field with information is formed near the human body Field, through the quasi-electrostatic field with information to send and receive information.

Summarizing the present invention, as described above, the present invention utilizes the nature of the quasi-electrostatic field and the nature of the human body; by charging the human body in the range in which the quasi-electrostatic field is dominant, the human body is used as an antenna; The quasi-electrostatic field is used as an information transmission medium. The following describes embodiments to which the present invention is applied.

(2) First embodiment (2-1) Overall configuration of the communication system according to the first embodiment In FIG. 5, reference numeral 1 generally denotes the overall configuration of the communication system according to the first embodiment. The communication system includes a ticket inspection and receipt machine 2 provided at a specific site, and a card-shaped mobile device (hereinafter referred to as a card device) 3, which is inserted into the human body using the ticket inspection and receipt machine 2 ( Hereinafter referred to as the user's clothing pocket.

The ticket checking and collecting machine 2 has an entrance/exit passage part 4 installed at a predetermined position of the station as a user passage, and a switchable exit door 5 provided on the exit side of the entrance/exit passage part 4. An electrode (hereinafter referred to as a side electrode) 7 is provided on the side surface of the entrance side of the entrance/exit passage portion 4.

The card device 3 has an electrode 8 (hereinafter referred to as an internal electrode) on one surface thereof and an electrode (hereinafter referred to as an external electrode) 9 on the other surface.

The communication system 1 is adapted to activate the card device 3 of a user passing through the entrance/exit passage section 4, perform near field communication between the card device 3 and the ticket inspection and ticket collector 2, and open the exit door in a closed state if necessary 5.

(2-2) Near Field Communication The following describes in detail the near field communication performed in the communication system 1 using a diagram showing the internal configuration of the ticket inspection and ticket collector 2 and the internal configuration of the card 3.

(2-2-1) Activation of the card device As shown in Figure 6, the control section 20 of the ticket inspection and ticket collection machine 2 is adapted to perform the overall control of the ticket inspection and ticket collection machine 2 according to a predetermined communication processing program, and is suitable The switching part 21a of the route switching device 21 is switched to the transmission connection terminal 21b and the reception connection terminal 21c based on a predetermined communication clock pre-stored in the information storage memory.

The transmitting section 23 supplies the alternating signal S1 of a predetermined frequency generated based on the AC power source 15 to the side electrode 7 via the route switching device 21 at the transmission timing based on the communication clock to generate static electricity which vibrates according to the alternating signal S1 via the side electrode 7 field.

Specifically, as described above with reference to FIGS. 2 and 3, by generating an alternating signal S1 with a frequency f and supplying the signal S1 to the side electrode 7, the transmitting part 23 is adapted to generate a quasi-electrostatic field from the side electrode 7 while preventing the radiation field And the induction field, where the frequency f satisfies the following formula obtained by substituting the above formula (10) into the above formula (12) and rearranging 12 after the substitution, and assuming that the relative permittivity ε of air is 1, The wavelength in the air is represented by λ. When the card device 3 and the ticket inspection and ticket collector 2 communicate with each other, the maximum distance between the external electrode 9 and the side electrode 7 is represented by r, and the frequency of the alternating signal S1 is represented by f: f< ;c2π·r...(13)]]>In this case, when the user enters the quasi-electrostatic field generated from the side electrode 7 (that is, when the user tries to pass through the entrance/exit passage portion 4) , The user in the quasi-electrostatic field is charged according to the displacement (displacement) of the side electrode 7 and thus used as an antenna. At the same time, the quasi-electrostatic field (hereinafter referred to as AC quasi-electrostatic field) TD according to the displacement is all around the surface of the user. Spread to the same sex.

In this case, as shown in FIG. 7, the internal electrode 8 of the card device 3 carried by the user is statically coupled with the user to form a capacitor c2, while the external electrode 9 is statically coupled with the ground to form a capacitor C3 and is connected to the side via the user. Electrode 7 (having a potential equal to ground) is statically coupled to form a capacitor C1.

As a result, as shown in FIG. 8, a circuit line is formed via the side electrode 7, the user, the internal electrode 8, and the external electrode 9 in sequence, and the external electrode 9 provides a reference potential for the AC power supply 15 in the card device 3 via the charged user. . Thereby, the voltage of the AC power supply 15 on the side of the ticket inspection and receipt machine 2 is applied between the internal electrode 8 and the external electrode 9 in the card device 3 via the charged user.

In this case, as shown in FIG. 9, the card device 3 connects the switching portion 31a on the internal electrode 8 side with the receiving connection terminal 31c, and connects the switching portion 31b of the external electrode 9 with the receiving connection terminal 31e; through the rectifier circuit 33 performs full-wave rectification of the alternating signal (current) S1 generated between the outer electrode 9 and the inner electrode 8; and stores the resulting direct current S2 as electric power in a smoothing capacitor HC.

The power supply control section 32 is adapted to activate the card device 3 when it detects that the power stored in the smoothing capacitor HC has reached a predetermined voltage level.

In this way, in the communication system 1, by electrifying the user to obtain power for the card device 3 from the user as a large antenna (electrode), it is possible to help supply power from the ticket inspection and ticket collecting machine 2 and in the card The device 3 side can obtain power without depending on the electrode area of the internal electrode 8 and the external electrode 9 and does not need to provide a battery for the card device 3.

In the process of achieving this task, the communication system 1 is suitable for enhancing the efficiency of power supply from the ticket inspection and ticket collecting machine 2 to the card device 3, and can realize the miniaturization of the entire system and the card device 3 itself.

Based on the frequency f of the alternating signal S1 provided by the ticket inspection and ticket collector 2, the card device 3 uses the clock generator 4 to generate a synchronization clock S3 corresponding to the communication clock of the ticket inspection and ticket collector 2, and synchronizes the clock S3 Provided to the control section 30.

The control section 30 is adapted to perform overall control of the card device 3 according to a predetermined communication processing program, and switch the switching parts 31a and 31b of the receiving connection terminal 31 based on the synchronized clock S3 provided by the clock generator 4.

The control section 30 is adapted to connect the switching section 31a to the receiving connection terminal 31d and connect the switching section 31b to the ground connection terminal 31f in the case of the transmission timing based on the synchronous clock S3, and to connect the switching section 31a to the ground connection terminal 31f in the case of the reception timing The receiving connection terminal 31c is connected and connects the switching portion 31b with the receiving connection terminal 31e.

(2-2-2) Near field communication from the card device to the ticket inspection and ticket collector. At the transmission timing based on the synchronized clock S3, the control section 30 reads the flag from the internal information storage memory (not shown) whether the user is allowed to enter Or identification information S4 of the departure station, such as the station name or train fare, for example, and the information is provided to the transmission section 35.

The transmitting section 35 generates an alternating signal with the same frequency as the ticket inspection and ticket collector 2 based on the electric power stored in the smoothing capacitor HC; performs modulation processing on the alternating information according to a predetermined modulation method to place the identification information S4 thereon; And the resultant identification signal S5 is provided between the internal electrode 8 and the external electrode 9 via the receiving connection terminal 31.

In this case, the internal electrode 8 vibrates according to the frequency of the identification signal S5 and generates a quasi-electrostatic field (identification signal S5) according to the vibration. As a result, the user is charged in response to the vibration of the internal electrode 8, thereby forming an isotropic quasi-electrostatic field (hereinafter referred to as an information transfer quasi-electrostatic field) DTD of the identification signal S5 around the user according to the vibration.

In this case, the user and the side electrode 7 are coupled to each other by the same role as in the case described with reference to FIGS. 7 and 8, and the information transfer quasi-electrostatic field DTD is detected by the side electrode 7.

In this way, in the emission part 35, the user's charging is changed according to the quasi-electrostatic field (identification signal S5) generated from the internal electrode 8 in the space in which the radiation field and the induction field are prevented as described above with respect to Equation 12. Status, can make the user use as an antenna and form an information transmission quasi-electrostatic field DTD.

In this case, the reception timing based on the communication clock is set for the ticket inspection and ticket collector 2 (FIG. 6), and the field effect transistor (hereinafter referred to as FET) 28 detects the information transmission accuracy detected by the side electrode 7 The intensity displacement of the electrostatic field DTD serves as a change in the potential via the gate of the FET 28, and it is supplied as an identification signal S6 to the receiving section 24 via an amplifier (not shown).

The receiving section 24 performs a demodulation process on the identification signal S6 according to a predetermined demodulation method to extract the identification information S7 and provides the identification information S7 to the channel determination section 25 of the control section 20.

Receiving the identification information S7 from the receiving section 24, the passage determination section 25 performs predetermined determination processing based on the identification information S7 and the determination information pre-stored in the information storage memory, and determines whether an attempt to pass through the entrance/exit passage section 4 (FIG. 5) The user passed.

When a positive result that the user should be allowed to pass is obtained, the passage determination section 25 gives a passage permission instruction to the exit gate control section 26 and the information providing section 27. Conversely, when a negative result that the user should not be allowed to pass is obtained, the passage determination section 25 gives a pass rejection instruction to the exit gate control section 26 and the information providing section 27.

When receiving the passage permission instruction from the passage determination part 25, the exit door control part 26 opens the exit door 5 of the entrance/exit passage part 4 (FIG. 5) to allow the user to pass. In contrast, when receiving the passage rejection instruction from the passage determination section 25, the exit door control section 26 keeps the exit door 5 of the entrance/exit passage section 4 closed to prevent the user from passing.

(2-2-3) Receiving the pass permission instruction from the passage determination section 25 or through the rejection instruction from the near field communication from the ticket inspection and ticket collector to the card device, the information providing section 27 generates notification information to be notified to the user S8 , Such as permission or rejection and other information, and then provide the notification information to the transmission section 23 at the transmission timing based on the communication clock.

The transmitting section 23 performs modulation processing on the alternating signal S1 according to a predetermined modulation method to place the notification information S8 thereon, and supplies the resultant notification signal S9 to the side electrode 7 via the route switching device 21 to be generated from the side electrode 7 A quasi-electrostatic field vibrating according to the notification signal S9.

Thus, the transmitting section 23 can change the charged state of the user according to the quasi-electrostatic field (notification signal S9) so that the user functions as an antenna, and prevent the radiation field and induction due to the induction of the quasi-electrostatic field described above with reference to FIGS. 7 and 8 In the space of the field, an information transmission quasi-electrostatic field DTD is formed in the vicinity of the user.

In this case, in the card device 3 (FIG. 9), the reception timing based on the synchronous clock S3 is set, and the internal electrode 8 detects the information transfer quasi-electrostatic field DTD formed in the vicinity of the user. The FET 37 detects the intensity displacement of the information transfer quasi-electrostatic field DTD detected by the internal electrode 8 as a change in the potential via the gate of the FET 37, and supplies it as a notification signal S9 to the receiving section via an amplifier (not shown) twenty four.

The receiving section 24 performs a demodulation process on the identification signal S9 according to a predetermined demodulation method to extract the identification information S10 and provides the identification information S10 to the control section 30.

In this case, the control section 30 notifies the user about the content of the notification information S10, for example, by displaying the content via a display section (not shown) based on the notification information S10.

In this way, the ticket checking and collecting machine 2 (card device 3) can avoid receiving via the side electrode by performing a half-duplex method of alternately switching the transmission route and the reception route based on the communication clock (synchronized clock S3) to send and receive information. 7. Notification signal S9 (identification signal S5) sent by (internal electrode 8) (so-called signal sneaking).

In this case, the ticket checking and collecting machine 2 (card device 3) can use only one side electrode 7 (internal electrode 8) to use the following two functions, that is, the function of the electric induction electrode for charging the user And the function of the detection electrode for detecting the change in the charged state of the user caused by the card device 3 (the ticket inspection and receipt machine 2), whereby the ticket inspection and receipt machine 2 can be miniaturized.

In addition, the ticket inspection and ticket collecting machine 2 can use an alternating signal S1 for both power supply and information communication so that one side electrode 7 can be used as both a transmitting electrode for power supply signals and an information communication signal. There is no need to provide such electrodes separately, so that the ticket inspection and ticket collector 2 can be miniaturized.

(2-3) In addition to the above configuration of the auxiliary device in the near field communication, as shown in FIG. 10, in the communication system 1, the floor surface of the entrance/exit passage portion 4 (hereinafter referred to as the route) The base surface) Y1 is provided so that the base surface Y1 is not connected to the ground (hereinafter referred to as the building base surface) Y2 but is separated from the building base surface at a predetermined interval dx (gap).

In this case, the electrostatic capacitance between the user's foot and the building base Y2 can be reduced to be less than the electrostatic capacitance between the user and the side electrode 7 corresponding to the distance between the route base Y1 and the building base Y2 The amount of dx can prevent the leakage of the information transmission quasi-electrostatic field DTD (alternating quasi-electrostatic field TD) from the foot to the building base surface Y2.

In addition, it can also prevent the noise (hereinafter referred to as environmental noise) KN caused by the inconsistency of the building base Y2 from being induced to the user from the route base Y1. The environmental noise KN is, for example, caused by the steel in the building base Y2. Discharge noise caused by electrical instability caused by gaps in the connection surface or the rust of the steel.

In this way, in the communication system, the information transmission quasi-electrostatic field DTD (alternating quasi-electrostatic field) can be formed in a more stable state when the user is charged and the electrical change is conducted on the periphery of the user's surface. Field TD) equipotential surface, which can stabilize near-field communication.

From the comparison between Fig. 11 showing the equipotential surface of the quasi-electrostatic field when the human body is used as an ideal dipole antenna and Fig. 12 showing the experimental result according to the present embodiment, it will be very clear visually .

In addition, as shown in FIG. 13, the ticket checking and collecting machine 2 of the communication system 1 is adapted to prevent the leakage of signals on the route from the side electrode 7 to the receiving portion 24 via the FET 28. Specifically, first, the housing 28A, that is, a conductor covering the periphery of the FET 28, is provided in a state of being electrically separated from the FET 28; secondly, only the receiving portion 24 is grounded on the receiving route.

Furthermore, as a means to prevent such leakage, compared with the electrostatic capacity SC2 on the route from the FET 28 to the receiving section 24 via the receiving section 24, the ticket inspection and ticket collecting machine 2 is suitable for example by adding the FET 28 and the ground. The distance (height) between the FET 28 and the ground reduces the electrostatic capacitance SC1 between the FET 28 and the ground.

In this way, the ticket checking and collecting machine 2 can effectively transmit the information detected by the side electrodes 7 to the quasi-electrostatic field DTD (alternating quasi-electrostatic field TD) via the FET 28 to induce the receiving portion 24, thereby receiving the information from the user with high sensitivity. The resulting information transmits a quasi-electrostatic field DTD (Figure 5).

(2-4) Operation and effect In the communication system 1 with the above configuration, the nature of the quasi-electrostatic field and the nature of the user (human body) are used to charge the user to act as an antenna, and thus a quasi-electrostatic field is formed near the user Used as an information transmission medium.

Specifically, as described above with reference to FIGS. 6 and 9, on the side of the card device 3 (ticket inspection and ticket collector 2) in the communication system 1, the identification signal S5 ( The quasi-electrostatic field of the notification signal S9) is generated from the internal electrode 8 (side electrode 7) to charge the user. In the ticket checking and collecting machine 2 (card device 3), the isotropic information transmission quasi-electrostatic field DTD (Figure 5) formed in the vicinity of the user sequentially passes through the side electrode 7 (internal electrode 8). And the FET 28 (FET 37) are detected, and the identification information S4 (notification information S8) is demodulated based on the detection result.

Therefore, in the communication system 1, it is possible to form an information transmission quasi-electrostatic field DTD that is sufficiently isotropically propagated from the surface of the user based on the identification signal S5 (notification signal S9) under the condition that the user is very well charged. In addition, transmission and reception are possible without depending on the manner in which the card device 3 is carried or installed, and without depending on whether the internal electrode 8 of the card device 3 is in contact with the user.

In addition, in the communication system 1, since a charged user is used as an antenna, it is possible to form a quasi-electrostatic field for information transmission isotropically propagating from the user's surface, regardless of the user's movement, and thus, without forcing the user to perform communication In the case of a scheduled action, you can send and receive information.

In addition, in the communication system 1, since a charged user is used as an antenna, and information is transmitted and received via a non-propagating information transmission quasi-electrostatic field DTD formed in the vicinity of the user, it is possible to avoid interaction with other radio waves (inductive field). Or radiation field) and avoid the interception from outside the communication space to ensure the confidentiality of the communication content.

In this way, in the communication system 1, the user intervening between the transmitting electrode and the receiving electrode can be used as an antenna, instead of treating the user as a medium as is conventionally done, the transmission and reception of information can be realized. There are no directional restrictions in the vicinity of the user, and confidentiality can be ensured without forcing the user to perform predetermined actions.

In addition to the above configuration, in the communication system 1, as described above with reference to formula (12), the relationship between the maximum distance r of the signal to be supplied to the side electrode 7 and the frequency f is selected to satisfy the above formula (13 ).

Therefore, in the communication system 1, when a user who is going to pass through the entrance/exit passage portion 4 is made to use as an antenna to perform near field communication, the communication space can be formed as a space in which a non-propagating quasi-electrostatic field E3θ always dominates ( Substantial enclosed space). As a result, the communication output can be reduced to the extent that the communication content does not spread outside the communication space, thereby more fully ensuring the confidentiality of the communication content.

According to the above configuration, in the communication system 1, the nature of the quasi-electrostatic field and the nature of the human body are used to charge the user to function as an antenna, and the information transmission quasi-electrostatic field DTD thus formed in the vicinity of the user is used as the information transmission medium. In this way, the transmission and reception of information can be realized without directional restrictions in the vicinity of the user, and confidentiality is ensured and the user does not need to be forced to perform predetermined actions, thereby enhancing the degree of freedom in the use of quasi-electrostatic field communication.

(2-5) Other Embodiments In the above-mentioned first embodiment, the description has been made on the case in which the card device 3 as the first communication device is inserted into the pocket of the user's clothes. However, the present invention is not limited to this, and the card device 3 may be installed around the arm as shown in FIG. 14. Alternatively, it can be incorporated in a mobile phone or pedometer, or it can be placed in a bag. That is, as described above, the card device 3 can be provided in the vicinity of the human body for transmission and reception without depending on the way of carrying or installing it and without depending on whether the internal electrode 8 of the card device 3 is in contact with the user. Ultimately, the only requirement is that the card device 3 should be in the vicinity of the user.

In the above-mentioned first embodiment, the description has been made on the case where the card device 3 has card formation. However, the present invention is not limited to this, and the card device 3 may have other various shapes.

In addition, in the above-mentioned first embodiment, the case where the route base Y1 is provided for the entrance/exit passage portion 4 in a state where it is separated from the building base Y2 (FIG. 10) by a predetermined interval dx The description. However, the present invention is not limited to this, and a member with a low relative dielectric constant can be filled between the route base surface Y1 and the building base surface Y2.

In this case, if it is assumed that the relative permittivity of the member filled between the route base plane Y1 and the building base plane Y2 is ε, and the gap between the route base plane Y1 and the building base plane Y2 is assumed to be dx, suppose The permittivity of vacuum electric constant (permittivity of vacuum electric constant) is ε0, and assuming that the area of the user's sole is S, the capacitance CY2 between the user's foot and the building base surface Y2 is approximately the value obtained from the relationship expressed by the following formula: CY2=ϵ0·ϵSdx...(14)]]> Therefore, if you consider the above relationship to choose the distance dx between the route base Y1 and the building base Y2 and fill it in the route base Y1 and the building The relative dielectric constant ε of the member between the base surface Y2, the electrostatic capacitance CY2 between the user's foot and the building base surface Y2 can definitely be smaller than the electrostatic capacitance between the user and the side electrode 7. Thus, it is possible to more safely prevent the information transmission quasi-electrostatic field DTD (alternating quasi-electrostatic field TD) from leaking from the user's foot to the building base surface Y2, and it is possible to more safely stabilize the near field communication.

In the above-mentioned first embodiment, the description has been made on the case where the route base Y1 is provided for the entrance/exit passage portion 4 in a state where it is separated from the building base Y2 (FIG. 10) by a predetermined interval dx , Wherein the route base Y1 is used as a coupling preventing device to prevent the marking target and the building base from being electrically coupled to each other. However, the present invention is not limited to this, but as shown in FIG. 16, it is possible to provide a noise absorbing ground line 40 laid on the route base Y1 and grounded to the building base Y2.

In this case, similar to the first embodiment described above, it is possible to prevent noise (hereinafter referred to as environmental noise) KN caused by the inconsistency of the building base plane Y2 from being induced to the user from the route base plane Y1 and thereby Stabilize near field communication. In addition, if not only the spacing dx but also the noise absorbing ground line 40 is provided between the route base Y1 (FIG. 10) and the building base Y2, the stability of the near field communication can be further enhanced.

Furthermore, in the above-mentioned first embodiment, the description has been made on the case where the side electrode 7 as the detection electrode and the power supply electrode uses one alternating signal S1 as both the power supply signal and the carrier signal. However, the present invention is not limited to this, but an electrode for power supply and an electrode for information communication may be separately provided.

Specifically, as shown in FIGS. 16, 17, and 18 in which the parts corresponding to the parts in FIGS. 6, 8, and 9 are represented by the same reference numerals and characters, in the ticket checking and collecting machine 2, at the entrance side A power supply electrode 51 separate from the side electrode 7 is newly provided on the inner surface of the inlet/outlet passage portion 4 of the, and an AC power source 15 is provided between the power supply electrode 51 and the ground. The side electrode 7 is only used for near field communication. In the card device 3, instead of the route switching device 31, the internal receiving electrode 52 and the internal transmitting electrode 53 are provided on one surface, and the external receiving electrode 54 and the external transmitting electrode 55 are provided on the other surface. If the transmission and reception on the power supply route and the transmission and reception on the information communication route are separately performed between the ticket inspection and ticket collector 2 and the card device 3 as described above, the same as the above-mentioned embodiment can be obtained. effect.

In addition, in the above-mentioned first embodiment, the description has been made regarding the case where the change in the charged state of the user (the information transmission quasi-electrostatic field DTD) that has been detected by the side electrode 7 as the detection electrode is The identification information S7 is detected by the FET 28 as the detection means, and the identification information S7 is demodulated by the receiving section 24 as the modulation means. However, the present invention is not limited to this, but the identification information S7 can be demodulated by measuring the change in the impedance of the information transmission quasi-electrostatic field DTD.

Specifically, as shown in FIG. 19 in which the components corresponding to those in FIG. 6 are denoted by the same reference numerals, the ticket checking and collecting machine 2 uses the transmitting section 23 to convert the alternating current with a predetermined frequency generated by the AC power supply 15 The signal S1 is supplied to the side electrode 7 via the route switching device 21 to generate a quasi-electrostatic field. Therefore, the receiving section 60 as the demodulation and impedance measurement device can obtain the same effects as the above-mentioned embodiment.

Furthermore, in the above-mentioned first embodiment, the description has been made on the case where the change in the charged state of the user is detected by the FET 28 or 37 as the identification signal S6 (notification signal S9). However, the present invention is not limited to this, but the change in the charged state of the user can be detected by various other detection devices, such as the use of a sensing electrode type having a transistor or FET configuration for measuring the voltage induced by the induced voltage Field meter, an induction electrode type modulation amplifier system field meter for AC conversion of DC signals obtained by induction electrodes using circuit breakers, vibration capacitors, etc., used to apply an electric field to a substance with a photoelectric effect to measure the substance The photoelectric effect type field meter, which is used only for the card device 3, the photoelectric effect type field meter, the shunt resistance type field meter, the current collection type field meter, etc., which change the light propagation characteristics caused by the

In addition, in the first embodiment, description has been made on the case where the alternating signal S1 is continuously supplied to the side electrode 7 by the transmitting section 23 as the modulation and power supply device. However, the present invention is not limited to this, and the signal may be altered only when the side electrode 7 as the detection electrode detects the field displacement caused by the user according to the user's walking motion when the user is approaching the entrance/exit passage portion 4 S1 is provided to the side electrode 7.

Specifically, the ticket checking and collecting machine 2 connects the switching section 21a of the route switching device 21 with the receiving connection terminal 21c under the control of the control section 20 until it is sequentially detected that it is passing through the entrance/pass through the side electrodes 7 and the FET 28. The user of the exit passage part 4 (FIG. 5) detects the displacement of the traveling quasi-electrostatic field caused by the user approaching the entrance/exit passage part 4, and the control part 20 switches when the detection result is sent to the sending part 23 The portion 21a is connected to the transmission connection terminal to send the alternating signal S1 to the side electrode 7. On the other hand, when the ticket checking and collecting machine 2 cannot detect the displacement of the traveling quasi-electrostatic field caused by the user walking away from the entrance/exit passage portion 4 via the side electrodes 7 and the FET 28 in sequence, it will no longer transmit When the detection result reaches the transmitting part 23, it connects the switching part 21a to the receiving connection terminal 21c through the control part 20 again and stops the supply of the alternating signal S1 to the side electrode 7. In this way, the ticket inspection and ticket collector 2 does not provide the alternating signal S1 to the side electrode 7 except when it detects the displacement of the traveling quasi-electrostatic field (electric) caused by the user's walking motion. Compared with the embodiment, energy saving can be enhanced more.

In addition, in the above-mentioned first embodiment, the card device 3 as the mobile first communication device provided near the user and the ticket inspection and receipt machine 2 as the second communication device provided at the predetermined control target The case of near-field communication between them is described. However, the present invention is not limited to this, and near field communication can be performed between the card device 3 provided on one user and the card device 3 provided on another card device 3 via the user or another user. In this case, the number of users via which the card device 3 provided on one user performs the near field communication from the card device 3 provided on another user may be any number. In this case, the same effect as the above-mentioned embodiment can be obtained.

In addition, in the above-mentioned first embodiment, the description has been made on the case where the ticket inspection and ticket collector 2 is applied to the present invention as the second communication device provided at the predetermined control target. However, the present invention is not limited to this. For example, the second communication device may be provided on or near video recorders, televisions, electronic devices such as mobile phones or personal computers, medical equipment, automobiles, desks, and other control targets to be controlled. In this case, the same effect as the above-mentioned embodiment can be obtained.

In addition, in the above-mentioned first embodiment, the description has been made on the case where the human body as the identification target is applicable to the present invention. However, the present invention is not limited to this, and organisms such as mammals, reptiles, plants, and even predetermined conductive materials and any other objects with charged properties to be identified can be widely applied to the present invention as identification targets.

In addition, in the above-mentioned first embodiment, the description is made on the case where the present invention is applied to the following communication system 1, which opens the exit door 5 as necessary to allow entry or exit from the entrance/exit passage 4 as a communication route . However, the present invention is not limited to this but can be widely applied to communication systems for various other purposes, such as communication systems used to open doors when necessary to allow entrance/exit passages for entering or leaving the company, with a desk A communication system with a nearby communication route for opening the door of the desk if necessary when the user approaches the desk, a communication system with a communication route near the personal computer for opening the personal computer when the user approaches the personal computer, the communication system for opening the personal computer when the user approaches the personal computer The transportation channel that transports the predetermined identification target is used as a communication route when the identification target is transported to the predetermined location if it is necessary to switch the communication system of the transportation channel, that is, the human body is charged so that the human body is used as an antenna and the quasi static electricity formed near the human body is used Any communication system in which the field is used as an information transmission medium to send and receive information.

(3) Second embodiment (3-1) Overall configuration of the communication system according to the second embodiment In FIG. 20, reference numeral 100 denotes the overall configuration of the communication system according to the second embodiment, which includes the buttocks inserted into human clothes The sound reproducer 102 in the pocket and the headset device 103 worn on the human head.

The sound reproducer 102 has a card shape, and a parallel plate type electrode portion (hereinafter referred to as a transmission electrode portion) 105 is provided in the sound reproducer 102. The transmission electrode portion 105 includes a transmission electrode 105a and a reference paired with the transmission electrode 105apole105b.

In this case, the sound reproducer 102 reproduces a sound signal from the sound storage medium and generates a quasi-electrostatic field modulated according to the reproduced sound signal from the transmission electrode portion 105 and thereby charges the human body.

The headset device 103 includes a hair band part 103A and a pair of ear pad parts 103L, 103R provided at the ends of the hair band part 103A. The hair band portion 103A has a parallel plate electrode portion (hereinafter referred to as a receiving electrode portion) 106. The receiving electrode portion 106 includes a receiving electrode 106a generally located at the center thereof and a reference electrode 106b paired with the receiving electrode 106a.

In this case, the headset device 103 detects the change in the charged state of the human body charged by the sound reproducer 102 as a change in the electric field close to the receiving electrode portion 106, specifically the electrodes 106a and 106a of the receiving electrode portion 106 The potential difference between 106b demodulates the sound signal obtained as a result, and then outputs a sound based on the sound signal from a speaker (not shown) included in the ear pad portions 102L, 102R.

As described above, the communication system 100 is adapted to detect the quasi-electrostatic field generated from the transmitting electrode portion 105 of the sound reproducer 102 as the potential difference between the electrodes 106a and 106b of the receiving electrode portion 106 of the headset device 103 in order to achieve the The human body performs near field communication of sound signals.

In the above-mentioned first embodiment, the near field communication utilizes a connection between an electrode (internal electrode 8) provided on the human body and an electrode (side electrode 7) provided at a predetermined position (on the entrance/exit passage portion 4). Implementation of the potential difference. However, since the phase of the signal reaching the device on the receiving side via the human body and the phase of the signal received from the electrode of the device on the receiving side via the electric field formed in the air are physically opposite, these signals counteract each other. ) And therefore sometimes cannot receive them.

Especially on the transmitting side, compared with the quasi-electrostatic field, the induction field and radiation field, which are not easily attenuated with respect to the distance, cause a waste of transmission power, and because of these fields, it is impossible to obtain the "difficult to propagate far" characteristic of near-field communication. advantage.

Therefore, in this embodiment, in the communication 100, the sound reproducer 102 as the transmitter and the headset device 103 as the receiver are designed so that the radiation field and the induction field are lower than the noise floor level. level) and assume that the potential difference between the electrodes 106a and 106b of the receiving electrode portion 106 at the position where the receiving electrode portion 106 is used exceeds the level that can be detected by the preamplifier 121.

Thereby, the communication system 100 can optimize the energy required for near field communication performed by the transmitter and receiver (the sound reproducer 102 and the headset device 103), and can prevent unnecessary propagation and improve the spatial resolution to Enhance the stability of communication.

(3-2) Configuration of the sound reproducer As shown in FIG. 21, the sound reproducer 102 includes a sound reproduction section 111, a modulation processing section 112, an amplifier 113, and a transmission electrode section 105.

The transmitting electrode portion 105 has an electrode structure (electrode shape, electrode area, and distance between electrodes) selected according to a design method for the transmitter and receiver and transmitter described later. Specifically, it is formed with an electrode structure according to the reference frequency, so that the intensity of the induced field component of the generated electric field is lower than the noise floor specified according to the communication frequency band.

The sound reproduction section 111 reproduces the sound signal S1 from a sound storage medium installed in an unshown installation section, and sends the reproduced sound signal S1 to the modulation processing section 112.

The modulation processing section 112 includes a signal supply section 112a and a modulation section 112b. For the signal supply portion 112a, the potential corresponding to the pre-designated start frequency (operating frequency) is set as the potential of the voltage signal to be applied to the transmission electrode portion 105.

The signal supply section 112a is adapted to supply a voltage signal having a designated start frequency and potential to the modulation section 112b at a predetermined timing. The modulation section 112b is adapted to perform modulation processing on the voltage signal according to a predetermined modulation method to place the sound signal S1 thereon and apply the resulting modulated signal to the transmission electrode 105a of the transmission electrode section 105 via the amplifier 113.

In this case, the transmitting electrode 105a vibrates according to the initial frequency of the modulated signal S2; the quasi-electrostatic field generated in response to the vibration charges the human body; as a result, the vibration is almost isotropically formed around the human body. The quasi-electrostatic field.

In this way, the sound reproducer 102 is adapted to transmit information (sound signals) via the human body.

(3-3) The configuration of the headset device is shown in FIG. 22. The headset device 103 includes a receiving electrode part 106, a preamplifier 121, a demodulation part 122, a sound amplifying part 123 (123L and 123R), Speaker 124 (124L and 124R).

The receiving electrode portion 106 is formed with an electrode structure selected according to a design method for the receiver and transmitter described later. Specifically, the receiving electrode portion 106 is formed without depending on the electrode area and having the distance between the electrodes according to the reference frequency so that the intensity of the induced field component of the generated electric field is lower than the noise floor specified according to the communication frequency band.

The preamplifier 121 detects the potential difference between the electrodes 106a and 106b of the receiving electrode part 106 and sends it to the demodulation part 122 as a modulated signal S2. Since the input signal of the preamplifier is generally weak, it is desirable to use a preamplifier having a high input impedance as the preamplifier 121.

The demodulation section 122 performs demodulation processing on the modulated signal S2 supplied from the demodulation section 122 according to a predetermined demodulation method, and thereby generates a sound signal S1. It then sends the sound signal S1 to the speaker 124 (124L and 124R) via the sound amplifying part 123 (123L and 123R).

As a result, the sound based on the sound signal S1 is output from the speaker 124 (124L and 124R).

As described above, the headset device 103 is adapted to emit sound based on the sound signal S1 transmitted from the sound reproducer 102.

(3-4) Design method of transmitter and receiver The design method of the sound reproducer 102 as a transmitter and the headset device 103 as a receiver will now be described.

(3-4-1) Design parameters First, the design parameters in designing the transmitter and the receiver (the sound reproducer 102 and the headset device 103) are described below.

Design the transmitter and receiver using the following (A) and (B) as guidelines (hereinafter referred to as design guidelines): (A) The induced field generated from the transmitting electrode section 105 should be controlled to be lower than the noise floor; and ( B) The potential obtained between the electrodes 106a and 106b of the receiving electrode portion 106 should be higher than the noise of the preamplifier 121 (FIG. 16) installed on the receiver (headset device 103).

In order to design transmitters and receivers that meet the design guidelines, as the preprocessing part of the design, the following design parameters are selected in descending order of importance: (a) starting frequency and communication frequency band, (b) transmitting electrode part 105 The electrode area (including the electrode shape; the same below) and the distance between the electrodes, as well as the electrode area in the receiving electrode portion 106 and the distance between the electrodes, (c) the receiving electrode portion 106 and the transmitting electrode portion 105 are on the human body , And (d) Preamplifier 121.

In fact, in the process of selecting various design parameters (a) to (d), various conditions (hereinafter referred to as design conditions) are considered, such as the purpose of the communication system, the communication application used for communication, and even sufficient The size of the space for mounting the transmitting electrode portion 105 (receiving electrode portion 106) to the sound reproducer 102 (headset device 103).

(3-4-2) Potential between the electrodes in the receiving electrode portion The potential generated between the receiving electrode 106a and the reference electrode 106b of the receiving electrode portion 106 (hereinafter referred to as the inter-electrode potential) will be described below.

The inter-electrode potential of the receiving electrode portion 106 is an important element that can be said to mean communication performance. The FDTD method (Finite Difference Time Domain: a method that uses finite difference and time domain to solve Maxwell's equation as the basic electromagnetic equation) is used to simulate the potential between the electrodes.

Specifically, under the condition that the transmitting electrode portion 105 is placed at a position corresponding to the hip pocket of the human body model and the receiving electrode portion 106 is placed at a position corresponding to the top of the head as shown in FIG. It is assumed that a voltage of 1 [V] of 100 [MHz] is applied between, and simulations are performed under various other conditions. Figures 24 to 27 show the results of the simulation.

FIG. 24 shows the relationship between the electrode area of the receiving electrode portion 106 and the inter-electrode potential of the receiving electrode portion 106. In this case, the electrode area of the transmitting electrode section 105 is fixed at 8×4 [cm2]; the distance between the electrodes of the transmitting electrode section 105 is fixed at 2 [cm]; and the distance between the electrodes of the receiving electrode section 106 is fixed at 1 [ cm].

It is clear from FIG. 24 that even if the electrode area of the receiving electrode portion 106 changes, the potential between the electrodes hardly changes. This means that even if the electrode area of the receiving electrode portion 106 on the receiver side is reduced in the process of designing the transmitter and the receiver, the stability of communication can be ensured.

FIG. 25 shows the relationship between the inter-electrode distance of the receiving electrode portion 106 and the inter-electrode potential of the receiving electrode portion 106. The electrode area of the transmitting electrode section 105 is fixed at 8×4 [cm2], the distance between the electrodes of the transmitting electrode section 105 is fixed at 2 [cm]; and the electrode area of the receiving electrode section 106 is fixed at 4×4 [cm2].

It is clear from FIG. 25 that if the distance between electrodes of the receiving electrode portion 106 is represented by dR [m] and the potential between electrodes of the receiving electrode portion 106 is represented by VR [V], the distance between electrodes dR and the potential between electrodes VR conform to the following The relationship expressed by the formula.

VR(dR)=0.0005·dR... (15) In addition, FIG. 26 shows the relationship between the electrode area of the transmitting electrode portion 105 and the inter-electrode potential of the receiving electrode portion 106. In this case, the distance between electrodes of the transmitting electrode section 105 is fixed at 2 [cm]; the electrode area of the receiving electrode section 106 is fixed at 4×4 [cm2]; and the distance between electrodes of the receiving electrode section 106 is fixed at 1 [cm2] cm].

It is clear from FIG. 26 that the inter-electrode potential of the receiving electrode portion 106 is proportional to the electrode area of the transmitting electrode portion 105.

FIG. 27 shows the relationship between the distance between the electrodes of the transmission electrode portion 105 and the potential between the electrodes of the reception electrode portion 106. In this case, the electrode area of the transmitting electrode section 105 is fixed at 8×4 [cm2]; the electrode area of the receiving electrode section 106 is fixed at 4×4 [cm2]; and the distance between the electrodes of the receiving electrode section 106 is fixed at 1. [cm].

It is clear from FIG. 27 that the inter-electrode potential of the receiving electrode portion 106 is proportional to the distance between the electrodes of the transmitting electrode portion 105.

From the above simulation results [Figures 24 to 27], if the distance between electrodes of the receiving electrode portion 106 is represented by dR[m], the electrode area of the transmitting electrode portion 105 is represented by AS[m2], and the distance between electrodes of the transmitting electrode portion 105 Expressed by dS[m], and the potential to be applied between the transmitting electrode 105a and the reference electrode 105b of the transmitting electrode section 105 (hereinafter referred to as the applied potential) is expressed by VS[V], then the electrode of the receiving electrode section 106 The inter-potential VR[V] is shown by the following formula: VR=α×VS×AS×dS×dR...... (16) The electrode area of the receiving electrode portion 106 is not considered in the above formula (16) The reason is that the inter-electrode potential VR [V] of the receiving electrode portion 106 does not depend on the electrode area as shown in FIG. 24.

In the above formula (16), the constant α is the potential gradient between the electrodes of the receiving electrode portion 106 with respect to the potential applied to the transmitting electrode portion 105 and is dependent on the setting parameters (b) and ( c) The constant (hereinafter referred to as the parameter-dependent constant).

The potential VS applied to the transmission electrode portion 105 depends on the frequency f, and thus is actually expressed by the following formula.

VR(f)=a×VS(f)×AS×dS×dR As described above, the inter-electrode potential of the receiving electrode portion 106 can be formulated as shown in formula (17) as relative to the potential applied to the transmitting electrode portion 105 The relative potential according to the design parameter (b).

(3-4-3) Determination of parameter-dependent constants Therefore, only when the setting parameters (b) and (c) are selected can the parameter-dependent constants be determined by performing the simulation as shown in Fig. 23 with a predetermined electric field simulator α.

That is, the human body model is defined in the electromagnetic field simulator and each of the contents of the parameters (b) and (c) is set, and then, the transmission between the electrodes 105a and 105b of the electrode portion 105 is caused by using a signal having a certain frequency and a predetermined amplitude. The excitation of, the inter-electrode potential VR(f) generated at the receiving electrode portion 106 is calculated by simulation.

Here, since all the elements of formula (17) are known except for the parameter-dependent constant α, the parameter-dependent constant α can be determined by substituting the known value into the formula (17).

For example, in the following cases, as various conditions for the simulations in FIGS. 24 to 27, it is assumed that the electrode area AS of the transmitting electrode portion 105 is 8×4 [cm2], and the inter-electrode distance dS of the transmitting electrode portion 105 is assumed to be 2[cm], assuming that the distance dR between the electrodes of the receiving electrode portion 106 is 2[cm], assuming that the potential VS(f) to be applied to the transmitting electrode portion 105 is 1[V] of a single frequency, assuming that the transmitting electrode portion 105 is located At the hip pocket, and assuming that the receiving electrode portion 106 is located on the top of the human body, the inter-electrode potential VR(f) generated at the receiving electrode portion 106 is 0.0005 in the simulation result in Fig. 25 and as shown in formula (15) [ V]. Then, by substituting the corresponding value into the formula (17), 0.0005=α×1×0.0032×0.02×0.01 is obtained, so that the parameter-dependent constant α can be determined to be 781.25.

As described above, the parameter-dependent constant α based on the selected setting parameters (b) and (c) can be determined from the electric field simulator and formula (17). However, there is a certain corresponding relationship between the frequency and the distance between the transmitting side and the receiving side. Therefore, once the starting frequency of the setting parameter (a) is determined, the setting parameter (c) is determined to some extent. .

(3-4-4) The maximum potential that can be applied to the transmitting electrode section. When designing the transmitter and receiver with the setting parameters (a) to (c), determine the setting parameter (d) (to be provided to the transmitting electrode section 105). Potential) such that the intensity of the induced field component of the electric field generated from the transmitting electrode portion 105 is lower than the noise floor. Here, the maximum potential that can be applied to the transmission electrode portion 105 will be described.

By assuming "cosωt = 1" (the electric field intensity E is the largest at this time) and for simplifying the discussion, under the assumption that θ = π/2, formula (2) is rearranged, the electric field source in free space at time t (Transmitting electrode portion 105) The electric field intensity E at the position r near the position can be expressed as the following formula: E=Eθ=ql4πϵr3·(1+jkr+(jkr)2)·exp(-jkr). ..(18)]]> The received power p[W] received by the antenna (receiving electrode section 106) with the opening area K[m2] is expressed by the following formula: p=SK4π...(19)] ]>The received power density is represented by S[W/m2]. The relationship between the received power density S[W/m2] and the received electric field strength E is expressed by the following formula: S=E2120π...(20)]]> Therefore, the received power p[mW] is replaced by the formula (20) The following formula obtained by formula (19) is expressed as: p=SK4π=E2K480π2=1000·E2K480π2[mW]...(21)]]> By substituting formula (18) into formula (21) "E" determines the product ql of the charge q and the distance l of the charge to the minute dipole so that the product ql is 10 [dB] smaller than the noise floor nf [dBm] at the position r near the electric field source (transmitting electrode portion 105) , Get the following formula: 1000·E2K480π2=1000·(ql4πϵr3·|jkr·exp(-jkr)|)2·K480π2<10nf-1010...(22)]]>below The formula shows the maximum value of the product ql (hereinafter referred to as the maximum product) qlmax: 1000·(qlmax4πϵr2&

Actually, for example, in which the frequency f is 4 [MHz], the noise figure NF is 10 [dB], the communication frequency band B is 100 [kHz], the opening area K of the receiving electrode portion 106 is 0.03 [m2], and θ= In the case of π/2, it is clear from equation (24) that if the maximum product qlmax is 1.5×10-16, the output of the induction field at a distance of 105 0.05 [m] from the transmitting electrode part can be lower than the noise floor nf (=- 174+10+10log(1000000)=114[dBm]. However, in fact, if the product ql satisfies "ql<qlmax", the induced field component at a position r near the transmitting electrode portion 105 0.05 [m] can be lower To the noise floor nf.

Here, the following will confirm the relationship between the communication distance and the electric field strength of the combined electric field including the quasi-electrostatic field, the induction field, and the radiation field, and only the electric field strength of the induction field.

That is, by substituting θ=π/2 and qlmax=1.5×10-16 into the formula (18), the electric field strength E(Eθ) of the combined electric field is expressed by the following formula: E=Eθ=qlmax4πϵr3( 1+jkr+(jkr)2)·exp(-jkr)=1.5×10-164πϵr3(1+j2πfcr+(j2πfc)2)·exp(-jkr)...( 26)]]> By substituting the vacuum dielectric constant ε=8.85e-12, the frequency f=4, and the wavelength k=2πf/c (c: the speed of light) into the formula (26), the combined electric field intensity E and the electric field The near distance r of the source can be plotted by the relationship shown in FIG. 28.

The electric field intensity E of the induced field component defined by the following formula: E=qlmax4πϵr3(jkr)·exp(-jkr)...(27)]]> and the nearby distance r from the electric field source can be The relationship shown in Figure 29 is drawn.

It is clear from the comparison between FIG. 28 and FIG. 29 that, at the position r near the electric field source (transmission electrode portion 105), the intensity of the induced field is sufficiently smaller than that of the quasi-electrostatic field. Since the intensity of the radiation field not shown in FIGS. 28 and 29 is smaller than that of the induction field at the nearby position r, it is obviously smaller than the intensity of the quasi-electrostatic field.

In this way, if the frequency f, the noise index NF, the communication frequency band B, the opening area K of the receiving electrode portion 106, and the nearby distance r from the transmitting electrode portion 105 are specifically determined, the charge q is compared with the charge from the micro dipole. The maximum product qlmax of the distance l can be determined from equation (24).

The maximum product qlmax corresponds to the maximum potential that can be applied to the transmission electrode portion 105. Therefore, if the applied potential VS(AS, dS, f) to be applied to the transmitting electrode portion 105 can be determined using an electric field simulator so that the electrode area AS selected as the setting parameter (b) and the electrode area generated from the transmitting electrode portion 105 The electric field of the distance dS substantially corresponds to the curve in FIG. 28 obtained as a result of drawing based on the formula (26), then the limit position rneighbor (= the nearby distance r) in the communication range with the transmitting electrode portion 105 as its center The intensity of the induction field can be lower than the noise floor nf.

For example, when the electrode area AS is 4×4 [cm2] and the distance between the electrodes dS is 4 [cm] of the transmitting electrode portion 105 is arranged in the free space, and a single frequency f0 potential 1 [V] is applied to the transmitting electrode In the case of section 105, the electric field generated from the transmitting electrode section 105, which is multiplied by 0.002, almost corresponds to the curve of FIG. 28.

This means that if a potential VS (0.04×0.04, 0.04, f0) of 0.002 [V] is applied to the transmitting electrode portion 105, the sensing at the limit position rneighbor in the communication range with the transmitting electrode portion 105 as its center The intensity of the field is lower than the noise floor nf.

Thus, the maximum potential (hereinafter referred to as the maximum applicable potential) AVsmax(AS, dS, f) that can be applied to the transmitting electrode portion 105 and corresponding to the maximum qlmax(f) dependent on f is expressed by the following formula: AVSmax(AS,dS,f)=10-174+10+10log(B)-1010·480π21000·K·4πϵ·rneighbour3|j2πfcrneighbourπfcrneigh;exp(-j2πfcrneighbour)|&time VS(AS,dS,f0)qlmax(f0)...(28)]]> where the single frequency used by the electric field simulator in the simulation is denoted by f0, and the potential obtained by the simulation is denoted by VS(AS, dS, f0) said.

As an example, when applying each value to the corresponding term in the formula (28), the simulation result of the transmitting electrode portion 105 with an electrode area AS of 4×4 [cm2] and an electrode-to-electrode distance dS of 4 [cm] is applied ( The condition that the potential VS (0.04×0.04, 0.04, 4)) is 0.002 [V] is added to it. It is assumed that the maximum product qlmax obtained from equation (24) is 1.5×10-16 (a single frequency F0 is 4 [MHz], When the noise figure NF is 10 [dB], the communication band B is 100 [kHz], the opening area K of the receiving electrode portion 106 is 0.03 [m2], and θ=π/2), the maximum applicable potential is Use the following formula to express AVSmax(0.04×0.04,0.04,f)=10-174+10+10log(100000)10·480π21000·0.032·4πϵ·0.053|j2πfc0.05· exp(-j2πfc0.05)×0.002ql(4×106)...(29)]]> Figure 30 based on the above formula (29) shows the frequency f and the maximum applicable potential AVSmax(0.04× The relationship between 0.04, 0.04, f). It is clear from FIG. 30 that the electric field intensity of the induced field at a distance of 5 [cm] from the electric field source (transmitting electrode portion 105) can be lower than the noise floor at any frequency f.

As described above, the maximum applicable potential AVsmax (AS, dS, f) according to the selected setting parameters (a) to (c) can be obtained from the electric field simulator and equation (28).

(3-4-5) The choice of preamplifier will have When the preamplifier 121 of voltage noise is installed on the headset device 103, the preamplifier 121 can detect the potential with respect to the communication frequency band B [Hz] signal of.

Therefore, the preamplifier 121 can be selected to satisfy the following formula: VR(f)=α×VS(f)×AS×dS×dR>n/B...(30)]]>(3- 4-6) Conclusion To summarize the above description, the transmitter and receiver (sound reproducer 102 and headset device 103) can be designed according to the design process RT in FIG. 31.

That is, first, as a pre-processing of the design, (a) the starting frequency f and the communication frequency band B, (b) the distance between electrodes dS and the electrode area AS of the transmitting electrode portion 105 and the distance between electrodes dR of the receiving electrode portion 106, (c ) The positions of the transmitting electrode portion 105 and the receiving electrode portion 106 on the human body, and (d) the selection of the voltage noise n of the preamplifier 121 (step SP1).

Then, the human body model and the transmitting electrode section 105 and the receiving electrode section 106 with setting parameters (b) are defined in the electric field simulator; the transmitting electrode section 105 and the receiving electrode section 106 are placed corresponding to the setting parameters on the human body (c) The position on the human body model; when the excitation is induced between the electrodes 105a and 105b of the transmitting electrode section 105 by a predetermined applied potential VS(f) with the starting frequency f, the inter-electrode potential of the receiving electrode section 106 is shown VR(f) is determined (step SP2).

After that, the defined terms are replaced with the corresponding parts of equation (17) to determine the parameter-dependent constant α (SP3) in the case of designing the transmitter and the receiver with the setting parameters (b) and (c).

Then, the opening area K of the receiving electrode portion 106, the noise index NF, and the limit position rneighbor in the communication range with the transmitting electrode portion 105 as its center are determined, and the determined items and setting parameters (a) are used in the formula (24 ) To determine the maximum product qlmax.

The applied potential VS(AS, dS, f0) to be applied to the transmission electrode portion 105 is determined in the electrical simulator so that the transmission electrode portion 105 having the electrode area AS selected as the setting parameter (b) and the inter-electrode distance dS The generated electric field substantially corresponds to the electric field intensity E(Eθ) of the combined electric field obtained as a result of substituting the term regarding the determined maximum product qlmax into the formula (18) (step SP4).

Then, by substituting the predetermined applied potential VS (AS, dS, f0) into the formula (28), such a maximum applicable potential AVSmax (AS, dS, f) makes the communication range with the transmitting electrode portion 105 as its center The intensity of the induction field at the limit position rneighbor in the free space is smaller than the noise floor nf (step SP5).

Finally, confirm whether there is a condition that is lower than the maximum applicable potential AVSmax (AS, dS, f) and meets the condition that the inter-electrode potential VR(f) of the receiving electrode portion 106 is equal to or higher than the voltage noise of the selected preamplifier 121 Any applied potential VS(f) is used as the applied potential VS(f) to be supplied to the transmission electrode portion 105 (step SP6).

If there is no such applied potential VS(f) that satisfies these conditions, all or part of the setting parameters (a) to (d) are checked again, and based on the checked and changed setting parameters, the steps SP2 to SP2 are repeated. The process of step SP6.

On the contrary, if the applied potential VS(f) that satisfies these conditions exists, it means that the design of the transmitter and receiver is successful. The setup process is now over.

By performing the design process RT shown in FIG. 31 as described above, it is possible to determine the applied potential VS(f) to be applied to the transmitting electrode portion 105 according to arbitrarily selected setting parameters so as to be within a predetermined range of the electric field generated from the electric field source The intensity of the induced field component is lower than the noise floor level.

When it is assumed that the transmitter and the receiver can be attached at multiple positions, it is possible to determine the basis for each of the transmitter and the receiver at these positions by sequentially performing the process from step SP1 to step SP6 for all these positions Set the parameter to be applied applied potential VS(f).

(3-5) Operation and Effect In the above configuration, in the communication system 100, the transmitting electrode portion 105 is formed in a structure according to the reference frequency so that the intensity of the induced field component of the electric field is lower than the noise floor specified according to the communication frequency band.

Therefore, in the communication system 100, the energy required for communication is reduced by reducing the components of the induction field and the radiation field unnecessary for the electrostatic field communication, and the spatial resolution is increased due to the prevention of unnecessary propagation. In this way, the stability of communication can be enhanced.

In addition, in the communication system 100, the stability of communication can be more enhanced by limiting the voltage to be applied between the transmitting electrodes according to the reference frequency.

According to the above configuration, the transmitting electrode portion 105 is formed in a structure according to the reference frequency so that the intensity of the induced field component of the electric field is lower than the noise floor specified according to the communication frequency band. Therefore, the energy required for communication is reduced by reducing the components of the induction field and the radiation field that are unnecessary for communication with the electrostatic field, and the spatial resolution is increased due to the prevention of unnecessary propagation. In this way, the stability of communication can be enhanced and the degree of freedom in communication can be enhanced.

(3-6) Other embodiments In the second embodiment described above, the electric structure according to the reference frequency is selected based on the formula (16) so that the intensity of the induced field component of the electric field is lower than the noise floor specified according to the communication frequency band. The description. However, the present invention is not limited to this, and the structure can be selected based on any formula other than formula (16), such as a formula improved on the basis of formula (16).

In addition, in the second embodiment described above, as the generating means for generating the signal to be applied to the electrode having the electrode structure according to the frequency used, a setting corresponding to the pre-designated start frequency (operating frequency) is provided. The case where a signal with the set potential is generated and applied is described. However, the present invention is not limited to this. It is also possible to keep a plurality of frequencies and potentials corresponding to the frequencies in the table, refer to the table to determine the potentials corresponding to the frequencies used, and switch the predetermined potentials at a predetermined timing. The potential is applied to sequentially generate signals having a predetermined potential.

In this case, since multiple frequencies can be used to perform communication with the headset device 103, it is possible to enhance communication efficiency while maintaining the stability of communication.

In addition, in the above-mentioned second embodiment, regarding the positions of the transmitter and receiver, the case where the sound reproducer 102 is placed in the hip pocket of the human bodys clothing and the headset 103 is placed on the top of the human head are described. . However, the present invention is not limited to this, and the transmitter and receiver (the sound reproducer 102 and the headset device 103) may be placed in various other positions.

In addition, regarding the combination of the transmitter and the receiver, various other combinations of the transmitter and the receiver can be adopted, including the case of communication between a mobile phone and a personal computer. In this case, a set of the transmitting electrode part 105 and the receiving electrode part 106 are installed on both the transmitter and the receiver.

In addition, in this case, the information to be sent and received can be any information except sound; the number of human bodies through which the information is transmitted can be any number, and organisms such as mammals, reptiles, and plants can be used to replace the human body. Body, even predetermined conductive materials and various other targets.

Industrial Applicability The present invention can be applied to a case where near field communication is performed using a potential difference between the electrodes of a transmitter and a receiver, and is particularly applicable to a case where information is transmitted and received via the human body.