JP2018175419A - Biological micro-vibration sensor device and sensor input unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a biological micro-vibration sensor device and a sensor input unit in which noise being generated in a connection line with an outer conductor can be eliminated from a sensor signal more efficiently.SOLUTION: A biological micro-vibration sensor device comprises a sensor body for detecting micro-vibration emitted from a living body and outputting a sensor signal, a sensor input unit (4) where the sensor signal is input, and a connection line (3) for conducting the sensor signal from the sensor body to the sensor input unit. The connection line comprises two core lines (3a, 3b) and an outer conductor (3c) for covering a core line. The sensor input unit comprises an instrumentation amplifier part (10). The instrumentation amplifier part comprises a pair of differential input terminals (IN(+), IN (-)) to which a voltage of the core line is applied, and a reference terminal (E) to which a voltage of the outer conductor is applied.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a biological micro-vibration sensor device and a sensor input device.

  A living body is known to be a biological signal transmitted as minute vibration on the surface of a body by vibes, pulsation, eye movement and the like. A sensor detects and derives such a biosignal.

  For example, it is known to fix a piezoelectric element to an eyelid and detect eye movement (see, for example, Non-Patent Document 1).

  Conventionally, for example, when the sensitivity of the sensor is low, it has been difficult to extract only a necessary signal because external noise mixes in the biological signal due to AC noise or movement of a living body.

  As measures against such external noise, for example, it is performed to prevent noise from the outside of the shield line by using the shield line as a transmission path for transmitting the signal of the vibration sensor to the determination means (patented patent) Reference 1).

  It is described in patent document 1 that the impedance inside a shield wire changes and a noise is generated in the body vibration signal transmitted from a vibration sensor, when a shield wire shakes or moves.

  Further, as means for suppressing the generation of noise, it is described that an operational amplifier is provided between the vibration sensor and the judging means to reduce the output impedance of the vibration sensor.

JP, 2015-208513, A

Kenichi Ooyama, et al., “Operative eye movement monitoring using a piezoelectric element in sphenoid cavity surgery”, Journal of Japan Endocrine Society, Vol. 84 Suppl. June 2008, p. 40-42

  However, although it is described that noise is reduced by reducing the output impedance of the vibration sensor described in Patent Document 1, the details of the operational amplifier are not described.

  Further, Patent Document 1 detects a vibration generated by the movement of the body of a person sleeping in a bed or a person sitting in a chair. In order to detect biological micro-vibrations generated on the body surface due to vibrations, pulsations, eye movements, etc., it is required that the noise be further reduced, but an effective noise reduction method has not been proposed yet.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a living body vibration sensor device and a sensor input device capable of reducing noise generated in a connection line including an outer conductor.

  The living body micro-vibration sensor device according to one aspect of the present invention detects a micro-vibration generated by a living body and outputs a sensor signal, a sensor input unit to which the sensor signal is input, and the sensor input from the sensor body A connecting wire for conducting the sensor signal, the connecting wire including two core wires and an outer conductor for covering the core wires, and the sensor input unit includes an instrumentation amplifier The instrumentation amplifier unit includes a pair of differential input terminals to which a voltage of the core wire is applied, and a reference terminal to which a voltage of the outer conductor is applied.

  According to this configuration, even if the connection line becomes unstable and noise is superimposed on the sensor signal, the principle of the differential amplifier attenuates the in-phase signal superimposed on the sensor signal and reduces noise from the output signal. be able to.

  In the biological micro-vibration sensor device according to one aspect of the present invention, preferably, the sensor main body detects the micro-vibration on a body surface of the living body.

  The sensor input device according to one aspect of the present invention includes an instrumentation amplifier unit that amplifies a sensor signal that a sensor main body detects and outputs a minute vibration generated by a living body, and the instrumentation amplifier unit includes the sensor main body from the sensor main body. A pair of differential input terminals to which a voltage of a core wire of a connecting wire for transmitting a signal is applied, and a reference terminal of the connecting wire to which a voltage of an external conductor covering the core wire is applied Do.

  In the sensor input device according to one aspect of the present invention, it is preferable that the sensor main body detect the minute vibration on a body surface of the living body.

  According to the present invention, it is possible to provide a living body vibration sensor device and a sensor input device capable of reducing noise generated in a connecting line including an outer conductor.

It is a schematic diagram which shows the biological micro-vibration sensor apparatus of this Embodiment. It is a circuit diagram showing the instrumentation amplifier part in the living body minute vibration sensor device of this embodiment.

  Hereinafter, the biological micro-vibration sensor device of the present embodiment will be described with reference to the attached drawings. FIG. 1 is a schematic view showing a biological micro-vibration sensor device of the present embodiment. The schematic view of the biological micro-vibration sensor device shown in FIG. 1 is simplified to explain the present invention, and it is assumed that the configuration of the biological micro-vibration sensor device is generally provided.

  As shown in FIG. 1, the biological micro-vibration sensor device 1 includes a piezoelectric element 2 which is an example of a sensor body of the present invention. The piezoelectric element 2 includes an upper electrode 2a, a piezoelectric member 2b, and a lower electrode 2c, and is configured to sandwich the piezoelectric member 2b between the upper electrode 2a and the lower electrode 2c.

  Furthermore, the periphery of the upper electrode 2a, the piezoelectric member 2b and the lower electrode 2c can be covered with an insulating case 2d made of an insulator. In this case, in the portion of the insulating case 2d corresponding to the lower electrode 2c, the thickness of the insulator is increased, and the pressing portion 2e protruding in the downward direction in the drawing is provided to transmit stress to the lower electrode 2c. it can.

  In the present embodiment, although the case of using piezoelectric ceramics as the piezoelectric element 2 has been described as an example, the present invention is not limited to this. For example, a piezoelectric film (piezo film) is covered with an insulating film Various types of things such as things can be used.

  The sensor main body such as the piezoelectric element 2 is configured to detect a micro-vibration (hereinafter referred to as a biological micro-vibration) generated by a living body and output an electric signal (hereinafter referred to as a sensor signal).

  The biological microvibration is not particularly limited as long as it is generated by the living body, but the effect of the present invention is most pronounced, for example, on the body surface of the living body by biological activity such as IBIKI, pulsation or eye movement. It is a minute vibration that appears.

  Here, the living body includes not only humans but animals other than humans. Moreover, although a body surface is skin, for example, it is not particularly limited.

  The method of attaching the sensor body to the living body is not particularly limited. For example, when the sensor body is the piezoelectric element 2 as shown in FIG. 1, it is attached to the body surface of the living body by sticking or the like. At this time, the pressing portion 2e side of the piezoelectric element 2 is directed to the body surface side. There may be nothing between the skin and the piezoelectric element 2 and it may be directly attached, or hair, clothes, gauze, bandages, etc. may be attached between the skin and the skin.

  The piezoelectric element 2 is connected to an input box 4 which is an example of a sensor input device of the present invention via a two-core shield wire 3 which is an example of a connection line of the present invention. The two-core shield wire 3 has two core wires 3a and 3b, and a shield sheath 3c covering the core wires 3a and 3b.

  The core wires 3a and 3b are, for example, electric wires in which a metal conductive wire (for example, a copper wire) is covered with an insulating material such as polyvinyl chloride (PVC). Here, core wires 3a and 3b are also referred to as central conductors or signal lines.

  The shield cover 3c, which is an example of the outer conductor of the present invention, is made of, for example, horizontal winding, a braid, or a tape made of a conductive metal (for example, copper wire, copper foil). A conductive resin layer (for example, a resin layer containing carbon) may be provided between the core wires 3a and 3b and the shield sheath 3c.

  The outer periphery of the shield sheath 3c of the two-core shield wire 3 is covered with an insulating layer (not shown) made of an insulating material such as polyvinyl chloride (PVC), for example.

  The ends of the core wires 3a and 3b of the two-core shield wire 3 on the piezoelectric element 2 side (input side) are connected to parts of the upper electrode 2a and lower electrode 2c of the piezoelectric element 2 by soldering, for example It is comprised so that conduction | electrical_connection is mutually possible.

  Plugs 5a and 5b are connected to ends of core wires 3a and 3b of the two-core shield wire 3 on the input box 4 side (output side), respectively. The plugs 5a and 5b are detachably connectable to the jack (minus side) 4a and the jack (plus side) 4b provided at the input terminal (IN) of the input box 4.

  One end of the lead wire 6 is connected to the shield cover 3c, and the shield cover 3c is configured to be conductive to each other. The plug 6 a is connected to the other end of the lead wire 6. The plug 6 a is configured to be detachably connectable to the jack 4 c provided to the reference terminal (E) of the input box 4.

  The jack 4 d provided at the output terminal (OUT) of the input box 4 is configured so that the plug 7 a provided at one end of the connection line 7 can be detachably connected. On the other hand, the plug 7 b provided at the other end of the connection line 7 is detachably connectable to the jack 8 a provided at the input terminal (IN) of the data processing device 8.

  The connection wire 7 is, for example, a wire in which a metal wire (for example, a copper wire) is covered with an insulating material such as polyvinyl chloride (PVC).

  With such a configuration, the sensor signal output from the piezoelectric element 2 is input to the input terminal (IN) of the input box 4 through the core wires 3 a and 3 b of the two-core shield wire 3. The input sensor signal is amplified by the input box 4 and output as an output signal from the output terminal (OUT). The output signal is input to the input terminal (IN) of the data processing device 8 through the connection line 7.

  The sensor signal (output signal) amplified by the input box 4 is subjected to data processing in the data processor 8. The data processing performed by the data processor 8 includes, for example, recording, storing, analyzing, analyzing, printing, displaying, amplifying and filtering sensor signals. The data processing device 8 includes, for example, an operation unit (CPU etc.), a storage unit (memory, hard disk etc.), a display unit (display etc.), a printing unit (printer etc.) and a user interface (keyboard, button, mouse, touch panel etc.) including. The data processing device 8 may be, for example, an information processing terminal device such as a personal computer, a smartphone, or a tablet.

  Next, an instrumentation amplifier unit included in the input box 4 of the biological micro-vibration sensor device 1 according to the present embodiment will be described with reference to FIG. FIG. 2 is a circuit diagram showing an instrumentation amplifier unit in the biological micro-vibration sensor device of the present embodiment. The instrumentation amplifier unit 10 shown in FIG. 2 includes a pair of operational amplifiers 11 and 12 constituting an input stage, and an operational amplifier 13 for amplifying a voltage difference between outputs of the operational amplifiers 11 and 12.

The non-inverting input terminal (+) of the operational amplifier 11 is configured to be applied with a voltage Vin ⁻ of the core wire 3 a of the two-core shield wire 3 connected to the input terminal IN (−) as a differential input terminal. ing. Therefore, the sensor signal output from the upper electrode 2a of the piezoelectric element 2 (see FIG. 1) is input to the non-inverting input terminal (+) of the operational amplifier 11.

  The inverting input terminal (-) of the operational amplifier 11 is connected to the inverting input terminal (-) of the operational amplifier 12 through the resistor R1. The inverting input terminal (-) of the operational amplifier 11 is connected to the output of the operational amplifier 11 via the resistor R2.

The non-inverting input terminal (+) of the operational amplifier 12 is configured to be applied with a voltage Vin ⁺ of the core wire 3b of the two-core shield wire 3 connected to the input terminal IN (+) as a differential input terminal. ing. Therefore, the sensor signal output from the lower electrode 2c of the piezoelectric element 2 (see FIG. 1) is input to the non-inverting input terminal (+) of the operational amplifier 12.

  The inverting input terminal (-) of the operational amplifier 12 is connected to the output of the operational amplifier 12 via the resistor R3.

  The output of the operational amplifier 11 is connected to the non-inverting input terminal (+) of the operational amplifier 13 via the resistor R4. The output of the operational amplifier 12 is input to the inverting input terminal (-) of the operational amplifier 13 via the resistor R5. The noninverting input terminal (+) of the operational amplifier 13 is connected to the output of the operational amplifier 13 via the resistor R6.

  The reference potential Vref is input to the inverting input terminal (−) of the operational amplifier 13 via the resistor R7.

  The output of the operational amplifier 13 is output as the output voltage Vout of the instrumentation amplifier unit 10.

  In the present embodiment, in the in-amp unit 10, the operational amplifiers 11 and 12 take the potential difference between the voltages applied through the core wires 3a and 3b to obtain the same phase of the sensor signal input from the core wires 3a and 3b. The signal can be removed, noise of the sensor signal can be reduced, amplified by the operational amplifier 13, and the reference potential Vref applied via the reference terminal (E) can be output as the output voltage Vout as the potential reference.

  Next, generation of noise in the two-core shield wire 3 of the biological micro-vibration sensor device 1 configured as described above will be described.

  The shield sheath 3c of the two-core shield wire 3 is useful for suppressing the influence of externally generated noise on the sensor signal passing through the core wires 3a and 3b. In general, the shield skin 3c is grounded (grounded).

  When the piezoelectric element 2 is attached to the body surface of a living body and microvibration is detected, the shield envelope 3c has no electric charge in a stable state, so that its potential can be regarded as zero. However, when the two-core shield wire 3 bends or shakes (unstable state) and a noise signal is superimposed, the shield sheath 3c comes to have a charge. As a result, the sensor signal input to the input box 4 through the core wires 3a and 3b is similarly superimposed as an in-phase signal, which causes noise.

  Therefore, in the present embodiment, the shield sheath 3c and the reference terminal (E) of the input box 4 are connected by the lead wire 6, and the voltage of the shield sheath 3c is obtained by the reference terminal (E of the instrumentation amplifier unit 10). ) Is applied as the reference potential Vref and input to the inverting input terminal (−) of the operational amplifier 13 via the resistor R7.

  Thereby, in the living body vibration sensor device 1 according to the present embodiment, when the two-core shield wire 3 is in the stable state and the potential of the shield sheath 3c is zero potential, the output voltage Vout is equal to the reference potential Vref. It becomes a subtracted voltage and noise is not superimposed.

  Further, even if the two-core shield wire 3 becomes unstable and noise is superimposed on the sensor signal, the in-amp unit 10 attenuates the in-phase signal superimposed on the sensor signal according to the principle of the differential amplifier. Noise disappears from the output voltage Vout. As a result, it is possible to reduce the noise generated in the two-core shield wire 3 provided with the shield sheath 3c.

  The embodiments of the present invention are not limited to the above-described embodiments, and various changes, substitutions, and modifications may be made without departing from the scope of the technical idea of the present invention. Furthermore, if technical progress of the technology or another technology derived therefrom can realize the technical concept of the present invention in another way, it may be implemented using that method. Therefore, the claims cover all the embodiments that can be included within the scope of the technical idea of the present invention.

  In the above embodiment, the two-core shield wire 3 is described as an example of the connection wire of the present invention, but two or more core wires may be used. Also, a coaxial cable may be used as a connection line.

  Although the case where the input box 4 and the data processing device 8 are connected by the connection line 7 is described as an example, the connection may be performed wirelessly.

  In addition, the data processing device 8 may be provided with communication means, and may be configured to transmit data to a server device that is an example of another data processing device connected via a network, and the server device processes the data. .

  Further, the instrumentation amplifier unit 10 is not limited to the configuration shown in FIG. 2 and may be configured of, for example, two operational amplifiers, or may be a monolithic instrumentation amplifier.

  As described above, the present invention can more efficiently remove from the sensor signal the noise generated in the connecting line provided with the outer conductor, so that in addition to the IBIKI measuring device, the pulsation measuring device and the eye movement measuring device, the living body is It is useful for the apparatus which measures the fine vibration to emit.

1 Biological microvibration sensor device 2 Piezoelectric element (sensor body)
3 2 core shield wire (connection wire)
3a, 3b core wire 3c shield skin (external conductor)
4 Input box (Sensor input device)
Reference Signs List 6 lead wire 7 connection wire 8 data processing device 10 instrumentation amplifier unit 11, 12, 13 operational amplifier

Claims (4)

A sensor body that detects a minute vibration generated by a living body and outputs a sensor signal;
A sensor input unit to which the sensor signal is input;
A connecting line for conducting the sensor signal from the sensor body to the sensor input;
Equipped with
The connection line includes two core wires and an outer conductor covering the core wires,
The sensor input unit includes an instrumentation amplifier unit,
The in-amp unit is
A pair of differential input terminals to which the voltage of the core wire is applied;
A reference terminal to which a voltage of the outer conductor is applied;
A biological micro-vibration sensor device characterized by including.   The biological micro-vibration sensor device according to claim 1, wherein the sensor main body detects the micro-vibration on a body surface of the living body. It has an in-amp unit that amplifies the sensor signal that the sensor body detects and outputs the minute vibration generated by the living body,
The in-amp unit is
A pair of differential input terminals to which a voltage of a core of a connecting wire for transmitting the sensor signal from the sensor body is applied;
A reference terminal of the connection line to which a voltage of an outer conductor covering the core wire is applied;
A sensor input device characterized by including.   The sensor input device according to claim 3, wherein the sensor body detects the slight vibration on a body surface of the living body.

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