JP2005079900A - Data communication apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stabilize signal transmission between a transmitter and a receiver, and to prevent data reception in the receiver from becoming impossible. <P>SOLUTION: A pair of holding parts 5 which protrude from a transmitter body 4 and hold first and second electrodes 2 and 3 at tips are disposed. Impedance components Z4 and Z5 of an equivalent circuit are reduced compared to a conventional case, and signal transmission between a transmitter 1 and a receiver 10 can be stabilized. Thus, data reception is prevented from becoming impossible in the receiver 10. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a data communication apparatus that uses a human body as a signal transmission path.

  As a data communication apparatus using a human body as a signal transmission path, the present applicant has already proposed the one shown in FIG. 8 (see Patent Document 1). This data communication apparatus includes a transmitter 1 attached to a human body H and a receiver 10 that receives data transmitted from the transmitter 1 and transmits the data to an external device 20 that uses the data. . The transmitter 1 is a data transmitting means for transmitting data by applying a signal voltage between the first electrode 2 and the second electrode 3 that are in contact with the skin of the human body H, and the first and second electrodes 2 and 3. (Not shown), a first electrode 2, a second electrode 3, and a transmitter main body 4 for holding data transmission means, which are attached to, for example, the upper arm of a human body H. On the other hand, the receiver 10 includes a receiving electrode 11 that contacts the human body H (for example, a finger) and data receiving means (not shown) that receives data by receiving a signal voltage applied to the receiving electrode 11 via the human body H. ).

Here, FIG. 9 shows an equivalent circuit in a state where the person H wearing the transmitter 1 is touching the reception electrode 11 of the receiver 10 with his / her finger. 9, Z1 is the impedance component of the human body H between the first electrode 2 and the second electrode 3 of the transmitter 1, and Z2 is the second electrode 3 of the transmitter 1 and the reception electrode 11 of the receiver 10. Z3 is the impedance component of the human body H between the first electrode 2 of the transmitter 1 and the earth ground, and Z4 is the impedance at the interface between the first electrode 2 of the transmitter 1 and the human body H. The component Z5 represents an impedance component at the interface between the second electrode 3 of the transmitter 1 and the human body H, and Z6 represents an impedance component at the interface between the reception electrode 11 of the receiver 10 and the human body H. Further, since the AC signal transmitted from the transmitter 1 to the receiver 10 is capacitively coupled between the earth ground and between the earth earth and the human body H, the capacitance components are represented by Z7 and Z8, respectively. . Further, Vhs represents a transmission voltage in the transmitter 1, Vdr represents a reception voltage in the receiver 10, and Zd represents an input impedance of the receiver 10. The transmission voltage Vhs is constant current controlled by the data transmission means so that the signal current becomes constant.
JP 2001-77735 A

  By the way, according to the equivalent circuit of FIG. 9, the transmission voltage Vhs of the transmitter 1 is attenuated by the impedance components of Z4 and Z5. Therefore, when these impedance components Z4 and Z5 increase, the transmission voltage Vhs increases by constant current control. However, the transmission voltage Vhs has an upper limit value determined by the power supply (for example, battery) of the transmitter 1, and signal transmission between the transmitter 1 and the receiver 10 when the transmission voltage Vhs exceeds the upper limit value. Becomes unstable, and in the worst case, data transmitted from the transmitter 1 may not be received by the receiver 10.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a data communication apparatus that stabilizes signal transmission between a transmitter and a receiver and prevents the receiver from receiving data. There is to do.

  In order to achieve the above object, the invention of claim 1 is a data communication device that uses a human body as a signal transmission path, and receives a transmitter attached to the human body and data transmitted from the transmitter. The transmitter is configured by a receiver that transmits data to an external device that uses the data. The transmitter applies a signal voltage between the first and second electrodes that are in contact with the human body and the first and second electrodes. Data transmitting means for transmitting data, and a transmitter main body for holding the first electrode, the second electrode and the data transmitting means, and the receiver includes a receiving electrode with which the human body contacts, and a human body via the human body A data communication apparatus comprising a data receiving means for receiving data by receiving a signal voltage applied to a receiving electrode, comprising a signal transmission stabilizing means for stabilizing signal transmission between a transmitter and a receiver. It is characterized by.

  According to the present invention, the signal transmission stabilizing means stabilizes the signal transmission between the transmitter and the receiver, thereby preventing the receiver from receiving data.

  According to a second aspect of the present invention, in the first aspect of the invention, the signal stabilization means includes a holding portion that protrudes from the transmitter body and holds the first and second electrodes at the tip.

  According to the present invention, the first and second electrodes are separated from the transmitter main body by the holding unit, whereby the impedance component at the interface between the first electrode of the transmitter and the human body, the second electrode of the transmitter, Signal transmission can be stabilized by reducing the impedance component at the interface with the human body to suppress the attenuation of the signal voltage.

  The invention of claim 3 is characterized in that, in the invention of claim 2, the protruding distance of the holding portion from the transmitter body is 0.8 to 1 mm.

  According to this invention, signal transmission can be stabilized while suppressing the protruding distance of the holding portion.

  According to a fourth aspect of the present invention, in the first aspect of the present invention, the signal stabilizing means includes at least one of a first electrode and a second electrode formed in a curved shape in which a contact surface with the human body is convex toward the human body. It consists of either of these and the press part which presses the said electrode formed in the curved surface shape to a human body.

  According to the present invention, the impedance component at the interface between the first electrode of the transmitter and the human body and the impedance component at the interface between the second electrode of the transmitter and the human body are reduced to suppress attenuation of the signal voltage. Signal transmission can be stabilized.

  The invention of claim 5 is characterized in that, in the invention of claim 4, the pressing portion can be pressed with a pressure of about 588 Newtons per square meter or more.

  The invention of claim 6 is characterized in that, in the invention of claim 1, the first and second electrodes are brought into contact with a human finger.

  According to the present invention, the impedance component of the human body between the first electrode and the second electrode increases, and the impedance component of the human body between the second electrode of the transmitter and the reception electrode of the receiver decreases. As a result, the reception voltage at the receiver increases, and as a result, the S / N ratio can be improved.

  The invention of claim 7 is characterized in that, in the invention of claim 1, at least a part of the receiving electrode is covered with a film made of an insulating material.

  According to the present invention, it is possible to improve the S / N ratio by preventing the propagation of noise from the human body to the receiver with the film covering the receiving electrode.

  According to the present invention, there is an effect that it is possible to prevent signal reception between the transmitter and the receiver by the signal transmission stabilizing means and prevent the receiver from receiving data.

  Hereinafter, embodiments of the present invention will be described in detail. However, since the basic configuration of the embodiment is the same as that of the conventional example, the same components are denoted by the same reference numerals, and illustration and description thereof are omitted as appropriate.

(Embodiment 1)
As described in the prior art, the impedance component at the interface between the first and second electrodes 2 and 3 of the transmitter 1 and the human body H, that is, the contact resistance Z4 between the first and second electrodes 2 and 3 and the human body H. , Z5 becomes large, signal transmission becomes unstable. Therefore, in order to stabilize signal transmission, it is necessary to reduce these impedance components (contact resistance) Z4, Z5.

  Therefore, in the present embodiment, as shown in FIG. 1, a pair of holding portions 5 that protrude from the transmitter body 4 and hold the first and second electrodes 2 and 3 are provided at the tips. The pair of holding portions 5 are provided so as to project apart from the surface of the transmitter body 4 facing the human body H, and the first and second electrodes 2 and 3 are fixed to the front end surfaces thereof by an appropriate method such as adhesion. ing. Although not shown, the transmitter body 4 is provided with a belt whose dimensions can be adjusted. The transmitter 1 is attached to the human body H by winding the belt around the arm or wrist of the human body H. It has come to be. Furthermore, the pressure by which the first and second electrodes 2 and 3 are pressed against the human body H can be adjusted by changing the length of the belt, and this belt allows the first and second electrodes 2 and 3 to be applied to the human body H. It is a pressing part to press.

Here, the pressure at which the first and second electrodes 2, 3 are pressed against the human body H while changing the protruding distance (hereinafter simply referred to as “distance”) L from the transmitter body 4 to the tip of the holding unit 5. An experiment was conducted to examine the relationship between the impedance components Z1 and Z4 and Z5 of the human body H between the first and second electrodes 2 and 3 of the transmitter 1, and the results are shown in FIG. It is shown in 2. In FIG. 2, the horizontal axis indicates the pressure [N / m ² ] at which the first and second electrodes 2 and 3 are pressed against the human body H, the vertical axis indicates the combined impedance Z [Ω], and the distance L is 0 mm and 0, respectively. The measured values at .5 mm, 1 mm, and 1.5 mm are indicated by ◇, □, Δ, and ○. Since the impedance component Z1 of the human body H between the first and second electrodes 2 and 3 is considered to be constant regardless of the distance L, from the result of FIG. It can be seen that Z4 and Z5 decrease.

On the other hand, considering the usage status of the transmitter 1, it is a problem that the distance L from the transmitter body 4 to the tip of the holding portion 5 is too large. Therefore, the standard value of the pressure with which the first and second electrodes 2 and 3 are pressed against the human body H is approximately 294 to 588 [N / m ² ], and the intermediate value thereof is 441 [N / m ² ]. FIG. 3 shows the result of examining the synthetic impedance Z [Ω] when the distance L is changed in the pressure range from 0.5 mm to 1.1 mm. As is apparent from FIG. 3, it was found that when the distance L is 0.8 to 1 mm, a synthetic impedance Z (contact resistance Z4, Z5) comparable to the distance L = 1.5 mm can be obtained.

  Accordingly, the holding unit 5 having a protrusion distance L of 0.8 to 1 mm is provided in the transmitter body 4 and the first and second electrodes 2 and 3 are held at the tip of the holding unit 5, thereby comparing with the conventional example. Thus, impedance components (contact resistance) Z4 and Z5 can be reduced to stabilize signal transmission between the transmitter 1 and the receiver 10, and as a result, it is possible to prevent the receiver 10 from receiving data. It can be done.

By the way, when the first and second electrodes 2 and 3 of the transmitter 1 are formed of copper foil (width 5 mm, length 40 mm) and composite impedance when formed of copper wire (diameter 4 mm, length 40 mm). The result of examining the relationship between Z and the pressure with which the first and second electrodes 2 and 3 are pressed against the human body H is shown in FIG. However, in FIG. 4, the case where ● is a copper foil and the case where □ is a copper wire is shown. As apparent from FIG. 4, if the pressure is 588 "N / m ^2] or more, towards the case of the copper wire composite impedance Z (contact resistance Z4, Z5) is small. That is, the first and When the second electrodes 2 and 3 are formed in a curved shape in which the contact surface with the human body H is convex toward the human body H, the contact resistances Z4 and Z5 are smaller than in the case of a planar shape such as a copper foil. It can be seen that the decrease is advantageous for stabilization of signal transmission.

  In any of the forms of the electrodes 2 and 3 shown in the present embodiment, the electrode is slightly curved along the human body H (for example, the longitudinal direction of the electrode is curved in the direction wound around the arm or wrist). Shape), there is an advantage that the degree of adhesion to the human body H is increased, contributing to the reduction of the contact resistances Z4 and Z5, and the wearing feeling is also improved.

(Embodiment 2)
In the data communication apparatus according to the present invention, there is a possibility that the S / N ratio of signal transmission may be reduced due to the influence of radiation noise or conduction noise from a power line. According to the equivalent circuit shown in FIG. 9, in order to improve the S / N ratio, the impedance component Z1 of the human body H between the first electrode 2 and the second electrode 3 is increased, or the transmitter 1 It is effective to reduce the impedance component Z2 of the human body H between the second electrode 3 and the reception electrode 11 of the receiver 10. That is, increasing the impedance component Z1 increases the reception voltage Vdr and improves the S / N ratio, and decreasing the impedance component Z2 also increases the reception voltage Vdr and improves the S / N ratio.

  Accordingly, when the first and second electrodes 2 and 3 (for example, disposable electrodes manufactured by Nihon Kohden Co., Ltd.) are brought into contact with the finger and the wrist by a distance R, the impedance component Z1 is examined. The results as shown in 5 were obtained. However, ◆ indicates a finger and ■ indicates a wrist. Here, the slope of the straight line connecting the measurement points of each distance R corresponds to Z1 per unit length. When the slope is obtained from FIG. 5, it is 1.46 [Ω / mm] for the wrist and 9.88 [Ω for the finger. / Mm]. Therefore, by bringing the first and second electrodes 2 and 3 into contact with the finger, the reception voltage Vdr in the receiver 10 is increased, and the S / N ratio can be improved.

  On the other hand, in order to reduce the impedance component Z2, the distance between the second electrode 3 of the transmitter 1 and the reception electrode 11 of the receiver 10 may be reduced. This is because the second electrode 3 is placed on the finger of the human body H. This can be achieved by bringing them into contact.

  If the first and second electrodes 2 and 3 of the transmitter 1 are in contact with the finger of the human body H as described above, the impedance component Z1 is increased and the impedance component Z2 is decreased to reduce the S / N ratio. It can be improved. If the distance between the first electrode 2 and the second electrode 3 is secured, for example, about the length of the finger, the impedance component Z1 increases in proportion to the distance, so that the S / N ratio is further improved. I can plan.

  The S / N ratio can also be improved by covering at least a part of the receiving electrode 11 with a film made of an insulating material. For example, a lighting fixture M that covers the surface of the receiving electrode 11 with a film formed of an insulating material such as PET (polyethylene terephthalate) and generates radiation noise at a position separated from the human body H by a distance K as shown in FIG. When the distance K at the communicable limit between the transmitter 1 and the receiver 10 was examined by changing the presence or absence of the film and the thickness of the film, the distance K without the film was 17 cm. The distance K when covered with a film with a thickness of 50 [μm] is 6 cm, the distance K when covered with a film with a thickness of 100 [μm] is 0 cm, and the receiving electrode 11 is covered with the film to radiate noise. It was found that the S / N ratio can be improved, and the effect of improving the S / N ratio increases as the film thickness increases.

  Furthermore, the waveform of the received signal in the receiver 10 in each of the cases of no film, 50 [μm] film, and 100 [μm] film with the distance K between the human body H and the lighting apparatus M fixed at 17 cm. The results of measuring are shown in FIGS. However, the scale on the vertical axis in FIGS. 7A to 7C is the largest in (a) and the smallest in (c). As can be seen from FIG. 7, the noise component is reduced by covering the receiving electrode 11 with a film. That is, while the film covering the receiving electrode 11 prevents the propagation of noise from the human body H to the receiver 10, the data signal transmitted from the transmitter 1 to the receiver 10 is only the contact point between the human body H and the receiving electrode 11. It is considered that the S / N ratio is improved because the attenuation of the data signal is suppressed because it is propagated through the space as well.

It is a top view of the transmitter in Embodiment 1 of the present invention. It is operation | movement explanatory drawing same as the above. It is operation | movement explanatory drawing same as the above. It is operation | movement explanatory drawing same as the above. FIG. 9 is an operation explanatory diagram of the second embodiment. It is operation | movement explanatory drawing same as the above. It is operation | movement explanatory drawing same as the above. It is a schematic diagram of a prior art example. It is an equivalent circuit diagram same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transmitter 2 1st electrode 3 2nd electrode 4 Transmitter main body 5 Holding part 10 Receiver 11 Reception electrode H Human body

Claims (7)

  A data communication device using a human body as a signal transmission path, a transmitter attached to the human body, a receiver that receives data transmitted from the transmitter and transmits the data to an external device that uses the data; The transmitter comprises: first and second electrodes that contact the human body; data transmission means for transmitting data by applying a signal voltage between the first and second electrodes; and the first electrode, A transmitter main body holding a second electrode and a data transmission means, and the receiver receives the data by receiving the reception electrode in contact with the human body and the signal voltage applied to the reception electrode through the human body. A data communication apparatus comprising a data receiving means, comprising: signal transmission stabilizing means for stabilizing signal transmission between a transmitter and a receiver.   2. The data communication apparatus according to claim 1, wherein the signal stabilization means includes a holding portion that protrudes from the transmitter body and holds the first and second electrodes at the tip.   3. The data communication apparatus according to claim 2, wherein a protrusion distance of the holding unit from the transmitter main body is set to 0.8 to 1 mm.   The signal stabilizing means includes at least one of the first and second electrodes formed in a curved shape in which the contact surface with the human body is convex toward the human body, and the electrode formed in the curved shape. The data communication device according to claim 1, further comprising: a pressing portion that presses the head.   5. The data communication apparatus according to claim 4, wherein the pressing portion can be pressed with a pressure of about 588 Newtons per square meter or more.   2. The data communication apparatus according to claim 1, wherein the first and second electrodes are brought into contact with a human finger.   2. The data communication apparatus according to claim 1, wherein at least a part of the receiving electrode is covered with a film made of an insulating material.

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