Biological information detection device

Abstract

To provide a biological information detection device capable of accurately detecting biological information in a situation where vibration from the outside other than a human body can be detected.SOLUTION: A biological information detection device includes: a first piezoelectric base material which is a piezoelectric base material provided in the support body installed at a predetermined place for detecting pressure received from a human body supported by the support body; a second piezoelectric base material which is a piezoelectric base material provided in the support body for detecting vibration of the support body; and a processor. The processor detects biological information on the basis of an output signal detected from each of the piezoelectric base materials.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a biological information detection device.

Background Art

[0002] In recent years, in order to detect the state of a driver driving a vehicle, a device has been disclosed that installs a sensor on the seat of the vehicle and detects the biological information of the driver from the seat.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Disclosure of the Invention

Problems to be Solved by the Invention

[0004] In the technology described in Patent Document 1, a biological information detection device is disclosed that includes a cover cushion having grooves on a pressure receiving surface that receives pressure from the human body, and a piezoelectric film sensor that detects biological information by receiving pressure from the human body through the cover cushion. The technology described in Patent Document 1 is characterized by accurately detecting biological information by providing grooves in the cover cushion.

[0005] However, in the biological information detection device described in Patent Document 1, since a piezoelectric film sensor is installed on a seat installed in a moving body such as a vehicle, vibration caused by the moving body may be detected. Further, the biological information detection device described in Patent Document 1 does not consider external vibration, and vibration caused by a moving body traveling in the vicinity may be detected. That is, the biological information detection device described in Patent Document 1 does not always accurately detect biological information in a situation where vibration from the outside other than the human body can be detected.

[0006] In view of the above circumstances, an object of the present invention is to provide a biological information detection device that can accurately detect biological information in a situation where vibration from the outside other than the human body can be detected.

Means for Solving the Problems

[0007] Means for solving the above problems include the following embodiments.

[0008] <1> A first piezoelectric substrate that is provided on a support installed at a predetermined location and that detects pressure received from a human body supported by the support, A second piezoelectric substrate that is provided on the support and that detects vibration of the support, A processor, and The processor is a biological information detection device that detects biological information based on output signals detected from each of the piezoelectric substrates.

[0009] <2> The support is fixed to a moving body as a predetermined location, The second piezoelectric substrate detects vibration of the support by the moving body The biological information detection device according to <1>.

[0010] <3> The first piezoelectric substrate and the second piezoelectric substrate are of the same type of piezoelectric substrate, The processor is Detecting a biological signal based on a differential signal between an output signal detected from the first piezoelectric substrate and an output signal detected from the second piezoelectric substrate The biological information detection device according to <1> or <2>.

[0011] <4> The processor is Identifying, as the biological information, data of a frequency at which a ratio between a first peak value in an analysis value of the FFT of an output signal detected from the first piezoelectric substrate and a second peak value corresponding to the first peak value in an analysis value of an output signal detected from the second piezoelectric substrate satisfies a predetermined condition The biological information detection device according to any one of <1> to <3>.

[0012] <5> The predetermined condition is when the ratio of the second peak value to the first peak value is 0.5 or less. The biological information detection device according to <4>.

[0013] <6> The first piezoelectric substrate is provided along the pressure receiving surface that receives pressure from the human body in the support. The biological information detection device according to any one of <1> to <5>.

[0014] <7> The second piezoelectric substrate is provided along the pressure receiving surface in the support and installed at a position farther from the human body than the first piezoelectric substrate. The biological information detection device according to <6>.

[0015] <8> The piezoelectric substrate is a long conductor, and a long piezoelectric body spirally wound in one direction around the conductor, and includes the biological information detection device according to any one of <1> to <7>.

[0016] <9> The piezoelectric body is a long organic piezoelectric body including an organic piezoelectric material having a piezoelectric constant d14. The biological information detection device according to <8>.

[0017] <10> The organic piezoelectric material is including an optically active polypeptide fiber indicating a fiber composed of an optically active polypeptide. The biological information detection device according to <9>.

[0018] <11> The piezoelectric body is an optically active helical chiral polymer (A). The biological information detection device according to any one of <8> to <10>.

[0019] <12> The helical chiral polymer (A) is polylactic acid <11> The biological information detection device according to the above.

Advantages of the Invention

[0020] According to the present invention, a biological information detection device capable of accurately detecting biological information in a situation where vibrations from the outside other than the human body can be detected is provided.

Brief Description of the Drawings

[0021]

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Figure 17

Embodiments for Carrying Out the Invention

[0022] Hereinafter, embodiments of the biological information detection device according to the present disclosure will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and the description will not be repeated.

[0023] [First Embodiment] [Biological Information Detection Device] With reference to FIG. 1, the biological information detection device 50 according to the embodiment of the present disclosure will be described. FIG. 1 is a schematic configuration diagram of the biological information detection device 50 according to the embodiment of the present disclosure.

[0024] As shown in FIG. 1, the biological information detection device 50 includes a first piezoelectric sensor 10A, a second piezoelectric sensor 10B, a first coaxial cable 20A, a second coaxial cable 20B, an instrumentation amplifier 30, and an information processing unit 40. The first piezoelectric sensor 10A is electrically connected to the instrumentation amplifier 30 via the first coaxial cable 20A. The second piezoelectric sensor 10B is electrically connected to the instrumentation amplifier 30 via the second coaxial cable 20B. The instrumentation amplifier 30 is electrically connected to the information processing unit 40. Here, the first piezoelectric sensor 10A is an example of the "first piezoelectric substrate", and the second piezoelectric sensor 10B is an example of the "second piezoelectric substrate".

[0025] The first piezoelectric sensor 10A has a first inner conductor 11A, a first piezoelectric body 12A, and a first outer conductor 13A. The first piezoelectric body 12A is located between the first inner conductor 11A and the first outer conductor 13A. The first inner conductor 11A and the first outer conductor 13A are not physically in contact. Details of the configuration of the first piezoelectric sensor 10A will be described later with reference to FIGS. 7 to 10.

[0026] When an external force F acts on the first piezoelectric body 12A, the first piezoelectric sensor 10A generates a first voltage between the first inner conductor 11A and the first outer conductor 13A due to the displacement of the first piezoelectric body 12A caused by the external force F. The first voltage indicates the potential difference of the first inner conductor 11A with respect to the first outer conductor 13A.

[0027] The external force F includes tension, pressure, and bending. The displacement of the first piezoelectric body 12A includes a recoverable deformation (hereinafter referred to as "non-plastic deformation") of the first piezoelectric body 12A corresponding to the external force F. The non-plastic deformation of the first piezoelectric body 12A includes partial or overall elongation and compression of the first piezoelectric body 12A.

[0028] The second piezoelectric sensor 10B has a second inner conductor 11B, a second piezoelectric body 12B, and a second outer conductor 13B. The second piezoelectric body 12B is located between the second inner conductor 11B and the second outer conductor 13B. The second inner conductor 11B and the second outer conductor 13B are not physically in contact. Details of the configuration of the second piezoelectric sensor 10B will be described later.

[0029] When an external force F acts on the second piezoelectric sensor 10B, a second voltage is generated between the second internal conductor 11B and the second external conductor 13B due to the displacement of the second piezoelectric body 12B caused by the external force F. The second voltage indicates the potential difference of the second internal conductor 11B with respect to the second external conductor 13B. The second voltage has the same positive and negative of the voltage as the first voltage.

[0030] The displacement of the second piezoelectric body 12B includes non-plastic deformation of the second piezoelectric body 12B corresponding to the external force F. The non-plastic deformation of the second piezoelectric body 12B includes partial or overall elongation and compression of the second piezoelectric body 12B.

[0031] In this embodiment, each of the first internal conductor 11A and the second internal conductor 11B extends in the direction D1. That is, the first internal conductor 11A and the second internal conductor 11B are substantially parallel. In other words, the first piezoelectric sensor 10A and the second piezoelectric sensor 10B are arranged substantially in parallel.

[0032] Substantially parallel means a relationship in which the first piezoelectric sensor 10A and the second piezoelectric sensor 10B can be regarded as parallel at first glance. Specifically, substantially parallel means that the angle formed by the first piezoelectric sensor 10A and the second piezoelectric sensor 10B is less than 10 degrees.

[0033] The first coaxial cable 20A has a first wire 21A, a first insulating layer 22A, and a first conductor layer 23A. The first wire 21A is electrically connected to the first internal conductor 11A of the first piezoelectric sensor 10A and the first differential input terminal V of the instrumentation amplifier 30 IN - . The first insulating layer 22A covers the first wire 21A. That is, the first wire 21A and the first conductor layer 23A are not physically in contact. The first conductor layer 23A is electrically connected to the first external conductor 13A of the first piezoelectric sensor 10A and the reference terminal V of the instrumentation amplifier 30 ref . The first conductor layer 23A covers the first insulating layer 22A.

[0034] Examples of materials for the first conductor 21A include copper. The material of the first insulating layer 22A can be any material with electrical insulation properties, such as fluororesin, polyethylene, polypropylene, amorphous polyolefin resin, polyethylene naphthalate, etc. Examples of materials for the first conductor layer 23A include copper, aluminum, etc. The first conductor layer 23A may be a braided wire. The first conductor layer 23A may be covered with a protective film. Examples of materials for the protective film include vinyl chloride resin, polyethylene terephthalate, polyimide, etc.

[0035] The second coaxial cable 20B has a second conductor 21B, a second insulating layer 22B, and a second conductor layer 23B. The second conductor 21B electrically connects the second internal conductor 11B of the second piezoelectric sensor 10B and the second differential input terminal V of the instrumentation amplifier 30. IN + That is, the second conductor 21B and the second conductor layer 23B are not physically connected. The second conductor layer 23B electrically connects the second external conductor 13B of the second piezoelectric sensor 10B and the reference terminal V of the instrumentation amplifier 30. The second conductor layer 23B covers the second insulating layer 22B. ref

[0036] Examples of materials for the second conductor 21B include the same materials as those exemplified for the material of the first conductor 21B. Examples of materials for the second insulating layer 22B include the same materials as those exemplified for the material of the first insulating layer 22A. Examples of materials for the second conductor layer 23B include the same materials as those exemplified for the material of the first conductor layer 23A. The second conductor layer 23B may be covered with a protective film. The configuration of the second coaxial cable 20B may be the same as or different from that of the first coaxial cable 20A.

[0037] The instrumentation amplifier 30 amplifies the potential difference between the input first voltage and second voltage and outputs the resulting differential voltage as a single output. The instrumentation amplifier 30 has a first differential input terminal V IN - and a second differential input terminal V IN + and a reference terminal V​ref and an output terminal V out and has. A first differential input terminal V IN - is an example of one differential input terminal. A second differential input terminal V IN + is an example of the other differential input terminal.

[0038] The information processing unit 40 converts the differential voltage output from the instrumentation amplifier 30 into a digital signal and performs data processing. The data processing includes display of the differential voltage, detection of the external force F, recording of the differential voltage, and the like. Details of the information processing unit 40 will be described later with reference to FIG. 2.

[0039] In the present embodiment, the first internal conductor 11A and the second internal conductor 11B are substantially parallel, but the present invention is not limited to this, and the first internal conductor 11A and the second internal conductor 11B may not be substantially parallel.

[0040] With reference to FIG. 2, the hardware configuration of the biological information detection device 50 according to the present embodiment will be described. FIG. 2 is a block diagram showing an example of the hardware configuration of the biological information detection device 50 according to the present embodiment.

[0041] As an example, as shown in FIG. 2, the biological information detection device 50 includes a first piezoelectric sensor 10A, a second piezoelectric sensor 10B, an instrumentation amplifier 30, and an information processing unit 40. The first piezoelectric sensor 10A, the second piezoelectric sensor 10B, the instrumentation amplifier 30, and the information processing unit 40 are electrically connected.

[0042] The first piezoelectric sensor 10A and the second piezoelectric sensor 10B are sensors that generate a voltage when pressure is input. The first piezoelectric sensor 10A detects the pressure received from the human body and the vibration of the support on which the first piezoelectric sensor 10A is provided, and the second piezoelectric sensor 10B detects the vibration of the support on which the second piezoelectric sensor 10B is provided.

[0043] The instrumentation amplifier 30 outputs a differential signal, which is a differential voltage obtained by amplifying the potential difference between the signals input from each of the first piezoelectric sensor 10A and the second piezoelectric sensor 10B.

[0044] The information processing unit 40 includes a processing PC 41 and an AD converter 42. The processing PC 41 includes a CPU (Central Processing Unit) 41A, a ROM (Read Only Memory) 41B, a RAM (Random Access Memory) 41C, a storage 41D, a communication I / F (Inter Face) 41E, a monitor 41F, and an input / output I / F 41G. The CPU 41A, the ROM 41B, the RAM 41C, the storage 41D, the communication I / F 41E, the monitor 41F, and the input / output I / F 41G are communicably connected to each other via a bus 41H.

[0045] The CPU 41A is a central processing unit that executes various programs and controls each part. That is, the CPU 41A reads a program from the ROM 41B or the storage 41D and executes the program using the RAM 41C as a work area. In the present embodiment, an execution program for executing various processes is stored in the storage 41D. By executing the execution program, the CPU 41A functions as a detection unit 71A, a conversion unit 72A, a specification unit 73A, a detection unit 74A, and an output unit 75A shown in FIG. 5.

[0046] The ROM 41B stores various programs and various data. The RAM 41C temporarily stores a program or data as a work area. The storage 41D as a storage unit is configured by an HDD (Hard Disk Drive) or an SSD (Solid State Drive) and stores various programs including an operating system and various data.

[0047] The communication I / F 41E is an interface for communicating with an external device, and communication standards such as 5G, LTE, and Wi-Fi (registered trademark) are used. The monitor 41F is a liquid crystal monitor for displaying the detected biological information. The input / output I / F 41G is an interface for communicating with each device constituting the biological information detection device 50.

[0048] The AD converter 42 converts the differential voltage, which is an analog signal output from the instrumentation amplifier 30, into a digital signal.

[0049] 〔Support〕 Next, with reference to FIG. 3, the support on which the first piezoelectric sensor 10A and the second piezoelectric sensor 10B are installed will be described. The support according to the present embodiment will be described in a form that is a vehicle seat 60 for a moving body installed on a moving body such as a vehicle. However, it is not limited thereto. The support may be any support as long as it is installed at a predetermined location and supports the human body. For example, supports such as a chair, a desk, a bed, a bed pad, and a sofa may be used.

[0050] The vehicle seat 60 is provided in a direction facing the front of the vehicle when the occupant is seated in the vehicle as a moving body. Therefore, the seat width direction coincides with the vehicle width direction, the seat depth direction coincides with the vehicle front-rear direction, and the seat height direction coincides with the vehicle up-down direction. Hereinafter, the seat direction will be simply referred to as the width direction, the seat depth direction will be simply referred to as the depth direction, and the seat height direction will be simply referred to as the height direction for explanation.

[0051] As an example, as shown in FIG. 3, the seat 60 for a moving body according to the present embodiment includes a seat cushion 61, a seat back 62, a first piezoelectric sensor 10A, and a second piezoelectric sensor 10B. The seat cushion 61 and the seat back 62 are pressurized when a vehicle occupant sits on and contacts them. Here, the seat cushion 61 and the seat back 62 are an example of a "support body" that supports the human body. In the present embodiment, a form in which the first piezoelectric sensor 10A and the second piezoelectric sensor 10B are provided on the seat cushion 61 will be described. However, it is not limited to this. The first piezoelectric sensor 10A and the second piezoelectric sensor 10B may be provided on the seat back 62, or the first piezoelectric sensor 10A and the second piezoelectric sensor 10B may be provided on an armrest (not shown).

[0052] As an example, as shown in FIG. 4, the seat cushion 61 includes a frame (not shown), an elastic body 63 such as urethane or sponge rubber provided on the frame, and a skin 64 that covers the surface of the elastic body 63.

[0053] The first piezoelectric sensor 10A and the second piezoelectric sensor 10B are placed on the elastic body 63 that constitutes the seat cushion 61, and can detect the biological information of the occupant sitting on the seat cushion 61 and the vibration of the seat cushion 61. Specifically, the first piezoelectric sensor 10A is placed directly below the skin 64 on the upper side of the seat cushion 61 and is sandwiched between the upper part of the elastic body 63. In other words, the first piezoelectric sensor 10A is arranged along the pressure receiving surface that receives the pressure P from the human body. Thereby, the first piezoelectric sensor 10A can mainly detect the pressure P of the occupant's human body received from the surface of the seat cushion 61. Note that the first piezoelectric sensor 10A can detect the pressure P by the human body and also detect the vibration of the seat cushion 61 due to vibrations from the vehicle and the outside.

[0054] Further, the second piezoelectric sensor 10B is placed directly above the skin 64 on the lower side of the seat cushion 61 and is sandwiched between the lower parts of the elastic bodies 63. The second piezoelectric sensor 10B is provided along the pressure receiving surface and is provided at a position away from the pressure receiving surface that receives the human pressure P as compared with the position where the first piezoelectric sensor 10A is placed. By being provided at a location away from the human body, the second piezoelectric sensor 10B can detect the vibration of the seat cushion 61 while suppressing the influence of the pressure P of the occupant's body received from the surface of the seat cushion 61. Note that the first piezoelectric sensor 10A and the second piezoelectric sensor 10B may be provided with cuts in the elastic body 63 and placed in the cuts.

[0055] The first piezoelectric sensor 10A and the second piezoelectric sensor 10B are provided in the width direction of the seat cushion 61 and are provided substantially in parallel. In the present embodiment, the form in which the second piezoelectric sensor 10B is placed at the lower part of the seat cushion 61 and provided substantially in parallel with the first piezoelectric sensor 10A has been described. However, the present invention is not limited to this. The second piezoelectric sensor 10B may be provided at any location on the seat cushion 61 as long as it is a location that is not easily affected by the human pressure P. For example, it may be provided at the lower part of the seat cushion 61 at a location where the occupant does not touch, such as the end in the depth direction.

[0056] (Operation of the biological information detection device) FIG. 5 is a block diagram showing an example of the functional configuration of the biological information detection device 50. As shown in FIG. 5, the biological information detection device 50 includes a detection unit 71A, a conversion unit 72A, a specification unit 73A, a detection unit 74A, and an output unit 75A. Each functional configuration is realized by the CPU 41A reading and executing an execution program stored in the storage 41D.

[0057] The detection unit 71A detects the differential signal in the instrumentation amplifier 30 via the input / output I / F 41G.

[0058] The conversion unit 72A uses a fast Fourier transform (FFT) to convert the differential signal detected by the detection unit 71A from a voltage signal for each time to a voltage signal for each frequency.

[0059] The specifying unit 73A specifies biological information using the analysis result of the FFT converted by the conversion unit 72A. Specifically, the specifying unit 73A specifies the peak value of the analysis value in the analysis result of the FFT to specify biological information. For example, the specifying unit 73A specifies the peak value of the analysis value related to the differential signal to specify biological information.

[0060] As an example, FIG. 6 shows the analysis value 80 of the differential signal as the analysis result of the FFT. For example, a voltage signal due to a heartbeat is detected at a frequency near 1 Hz. The specifying unit 73A specifies the peak value of the analysis value 80 shown in the range from 1 Hz to 1.2 Hz using the analysis result of the FFT shown in FIG. 6. The specifying unit 73A specifies the differential signal at the frequency related to the peak value as biological information derived from the heartbeat.

[0061] The detection unit 74A detects, as biological information, the differential signal related to the frequency specified from the differential signal for each time.

[0062] The output unit 75A outputs the biological information detected by the detection unit 74A to the monitor 41F. Note that the detected biological information may be output to an external device via the communication I / F 41E or may be stored in the storage 41D.

[0063] In the present embodiment, a mode has been described in which the frequency indicating biological information is specified from the analysis result of the FFT, and the biological information is detected from the voltage signal for each time using the specified frequency. However, the present invention is not limited to this. The differential signal related to the frequency specified as biological information from the analysis result of the FFT may be inverse Fourier-transformed to detect biological information.

[0064] (First piezoelectric sensor and second piezoelectric sensor) Next, with reference to FIGS. 1 and 7 to 10, the details of the first piezoelectric sensor 10A and the second piezoelectric sensor 10B will be described. FIG. 7 is a front view showing one aspect of the first piezoelectric sensor 10A according to the present embodiment. FIG. 8 is a sectional view taken along line VI-VI of FIG. 7. FIG. 9 is a front view showing another aspect of the first piezoelectric sensor 10A according to the present embodiment. FIG. 10 is a front view showing still another aspect of the first piezoelectric sensor 10A according to the present embodiment. In FIGS. 7, 9, and 10, the first external conductor 13A is omitted. Note that the second piezoelectric sensor 10B according to the present embodiment may have the same configuration as the first piezoelectric sensor 10A. Hereinafter, the description of the second piezoelectric sensor 10B will be omitted, and the first piezoelectric sensor 10A will be described.

[0065] As shown in FIG. 1, the first piezoelectric sensor 10A includes a first internal conductor 11A, a first piezoelectric body 12A, and a first external conductor 13A. The first internal conductor 11A extends in the direction D1. The first piezoelectric body 12A covers at least a part of the first internal conductor 11A. The first external conductor 13A is disposed on the outer periphery of the first piezoelectric body 12A.

[0066] The first piezoelectric sensor 10A is a linear object. The cross-sectional shape of the first piezoelectric sensor 10A in a plane orthogonal to the direction D1 is appropriately adjusted according to the use of the biological information detection device 50 and the like, and examples thereof include a circular shape, an elliptical shape, a rectangular shape, a cocoon shape, a four-leaf shape, a star shape, and an irregular shape. When the cross-sectional shape of the first piezoelectric sensor 10A is circular, the diameter of the first piezoelectric sensor 10A is preferably 0.1 mm or more and 10 mm or less. The length of the first piezoelectric sensor 10A in the direction D1 is appropriately adjusted according to the use of the biological information detection device 50 and the like, and is, for example, 1 mm or more and 100 mm or less.

[0067] <The first internal conductor> The first internal conductor 11A is a conductor for efficiently detecting an electrical signal from the first piezoelectric sensor 10A. As the first internal conductor 11A, it is preferably an electrically good conductor. For example, copper wire, aluminum wire, SUS (Steel Use Stainless) wire, metal wire coated with an insulating film, carbon fiber, resin fiber integrated with carbon fiber, brocade thread, organic conductive material, etc. may be mentioned. The brocade thread is formed by spirally winding a copper foil around a fiber. The outer diameter of the fiber is appropriately adjusted according to the desired characteristics of the first piezoelectric sensor 10A, and is preferably 0.1 mm or more and 10 mm or less. Among them, from the viewpoint of improving the piezoelectric sensitivity and the stability of the piezoelectric output and imparting high flexibility, the brocade thread or carbon fiber is preferable, and particularly, from the viewpoint of low electrical resistance, the brocade thread is preferable.

[0068] <First external conductor> The first external conductor 13A is a conductor paired with the first internal conductor 11A in order to detect an electrical signal from the first piezoelectric sensor 10A. The first external conductor 13A may be disposed on the outer periphery of the first piezoelectric body 12A, and may cover at least a part of the first piezoelectric body 12A. Specifically, the first external conductor 13A may cover a part of the outer peripheral surface of the first piezoelectric body 12A, or may cover the entire outer peripheral surface of the first piezoelectric body 12A. The first external conductor 13A is formed by winding a long conductor, for example. Examples of the cross-sectional shape of the long conductor include a circular shape, an elliptical shape, a rectangular shape, an irregular shape, etc. Among them, from the viewpoint of closely adhering to the first piezoelectric body 12A in a plane and efficiently generating the first voltage, the cross-sectional shape of the long conductor is preferably a rectangular shape. The material of the long conductor is not particularly limited, and mainly the following are mentioned depending on the cross-sectional shape. Examples of the long conductor having a rectangular cross-section include a copper foil ribbon obtained by rolling a copper wire having a circular cross-section into a flat plate shape, an aluminum foil ribbon, etc. Examples of the long conductor having a circular cross-section include copper wire, aluminum wire, SUS wire, metal wire coated with an insulating film, carbon fiber, resin fiber integrated with carbon fiber, brocade thread in which a copper foil is spirally wound around a fiber, etc. Alternatively, as the long conductor, one obtained by coating an organic conductive material with an insulating material may be used. Examples of the winding method of the long conductor include a method of spirally winding a copper foil or the like around the first piezoelectric body 12A, a method of forming a copper wire or the like into a cylindrical braid and wrapping the first piezoelectric body 12A therewith, and a method of integrally wrapping the first piezoelectric body 12A in a cylindrical shape.

[0069] <First piezoelectric body> When an external force F acts on the first piezoelectric body 12A, a first voltage is generated between the first internal conductor 11A and the first external conductor 13A. The first piezoelectric body 12A only needs to cover at least a part of the first internal conductor 11A, and may cover a part of the outer peripheral surface of the first internal conductor 11A or may cover the entire outer peripheral surface of the first internal conductor 11A.

[0070] The configuration of the first piezoelectric body 12A may be, for example, the following first configuration A, second configuration A, third configuration A, or fourth configuration A. In the first configuration A, as shown in FIG. 7, the first piezoelectric body 12A is formed by winding a first long organic piezoelectric body 121. The first long organic piezoelectric body 121 will be described later. In the second configuration A, as shown in FIG. 9, the first piezoelectric body 12A is formed by winding a first long organic piezoelectric body 121 and a second long organic piezoelectric body 122. The second long organic piezoelectric body 122 will be described later. In the third configuration A, as shown in FIG. 10, the first piezoelectric body 12A is formed by winding a braid structure. The braid structure is formed by alternately crossing a first long organic piezoelectric body 121 and a second long organic piezoelectric body 122. In the fourth configuration A, it is formed by winding a sheet-like piezoelectric body. The sheet-like piezoelectric body will be described later.

[0071] Hereinafter, the first long organic piezoelectric body 121, the first configuration A, the second long organic piezoelectric body 122, the second configuration A, the third configuration A, the sheet-like piezoelectric body, and the fourth configuration A will be described in this order.

[0072] (First long organic piezoelectric body) The first long organic piezoelectric body 121 is made of an organic piezoelectric material and has a piezoelectric constant d 14 .

[0073] Whether the "first long organic piezoelectric body 121 has a piezoelectric constant d 14 " is determined by the following first determination method. In the first determination method, a first piezoelectric sensor 10A and a first piezoelectric sensor 10B manufactured in accordance with Example 1 described later and a voltmeter are used.

[0074] Specifically, in the first determination method, a first piezoelectric sensor 10A and a first piezoelectric sensor 10B are manufactured in accordance with Example 1 described later. The rear end of the first internal conductor 11A of the first piezoelectric sensor 10A and the rear end of the first external conductor 13A of the first piezoelectric sensor 10A are electrically connected to the voltmeter. Next, a predetermined external force F is applied to the first piezoelectric sensor 10A to detect a determination voltage. Similarly, the rear end of the first internal conductor 11A of the second piezoelectric sensor 10B and the rear end of the first external conductor 13A of the second piezoelectric sensor 10B are electrically connected to the voltmeter. Next, the same external force F as the external force F applied to the first piezoelectric sensor 10A is applied to the second piezoelectric sensor 10B to detect a determination voltage.

[0075] In the first determination method, when the following condition (Y) is satisfied, it is determined that the "first long organic piezoelectric body 121 has a piezoelectric constant d 14 ". On the other hand, when the following condition (Y) is not satisfied, it is determined that the "first long organic piezoelectric body 121 has a piezoelectric constant d 14 " does not apply. (Y) The polarities of the determination voltages of the first piezoelectric sensor 10A and the second piezoelectric sensor 10B are opposite

[0076] The first long organic piezoelectric body 121 is a long object. Examples of the shape of the first long organic piezoelectric body 121 include a ribbon shape, a fiber shape, etc. The ribbon shape is a flat and elongated shape. The fiber shape may be in the form of a monofilament or a multifilament.

[0077] When the first long-strip organic piezoelectric body 121 is in a ribbon shape, the width of the first long-strip organic piezoelectric body 121 is preferably 0.1 mm or more and 30 mm or less. By the width being 0.1 mm or more, the strength of the first long-strip organic piezoelectric body 121 is ensured. Further, the manufacturing suitability of the first long-strip organic piezoelectric body 121 (for example, the manufacturing suitability in the slitting process described later) is also excellent. By the width being 30 mm or less, the degree of freedom (flexibility) of non-plastic deformation of the first long-strip organic piezoelectric body 121 is improved. When the first long-strip organic piezoelectric body 121 is in a ribbon shape, the thickness of the first long-strip organic piezoelectric body 121 is preferably 0.001 mm or more and 0.2 mm or less. By the thickness being 0.001 mm or more, the strength of the first long-strip organic piezoelectric body 121 is ensured. Further, the manufacturing suitability of the first long-strip organic piezoelectric body 121 is also excellent. By the thickness being 0.2 mm or less, the degree of freedom (flexibility) of non-plastic deformation in the thickness direction of the first long-strip organic piezoelectric body 121 is improved. When the first long-strip organic piezoelectric body 121 is in a ribbon shape, the ratio of the width of the first long-strip organic piezoelectric body 121 to the thickness of the first long-strip organic piezoelectric body 121 (hereinafter referred to as "ratio [width / thickness]") is preferably 2 or more. By the ratio [width / thickness] being 2 or more, the main surface of the first long-strip organic piezoelectric body 121 becomes clear. Therefore, the first long-strip organic piezoelectric body 121 is easily wound around the first external conductor 13A with the directions aligned over the length direction of the first long-strip organic piezoelectric body 121. For this reason, the first piezoelectric sensor 10A is excellent in piezoelectric sensitivity and also excellent in the stability of piezoelectric sensitivity.

[0078] When the first long-strip organic piezoelectric body 121 is in a fiber shape, examples of the cross-sectional shape of the first long-strip organic piezoelectric body 121 include a circular shape, an elliptical shape, a rectangular shape, a cocoon shape, a four-leaf shape, a star shape, an irregular shape, and the like. The major axis diameter of the cross-section of the first long-strip organic piezoelectric body 121 is preferably 0.0001 mm to 10 mm, more preferably 0.001 mm to 5 mm, and still more preferably 0.002 mm to 1 mm. The "major axis diameter of the cross-section" corresponds to the "diameter" when the cross-sectional shape of the first long organic piezoelectric body 121 is circular, and when the cross-sectional shape of the first long organic piezoelectric body 121 is not circular, it is the longest width among the widths of the cross-section. When the fiber shape is composed of multifilaments, the "major axis diameter of the cross-section" refers to the major axis diameter of the cross-section of the multifilaments.

[0079] The organic piezoelectric material may be any material as long as the first long organic piezoelectric body 121 has a piezoelectric constant d 14 Examples thereof include optically active polymers (A) and the like. Examples of the optically active polymer (A) include an optically active helical chiral polymer (A1) (hereinafter sometimes referred to as "helical chiral polymer (A1)"), an optically active polypeptide (A2) (hereinafter sometimes referred to as "optically active polypeptide (A2)"), and the like.

[0080] The "optically active helical chiral polymer (A1)" refers to a polymer having a helical structure in its molecular structure and having molecular optical activity. Examples of the helical chiral polymer (A1) include polylactic acid-based polymers, synthetic polypeptides, cellulose derivatives, polypropylene oxide, poly(β-hydroxybutyric acid), and the like. Examples of the polylactic acid-based polymer include a homopolymer of L-lactic acid (hereinafter referred to as "PLLA"), a homopolymer of D-lactic acid (hereinafter referred to as "PDLA"), and the like. PLLA has a left-handed helical structure in its molecular structure. PDLA has a right-handed helical structure in its molecular structure. Examples of the synthetic polypeptide include poly(γ-benzyl glutamate), poly(γ-methyl glutamate), and the like. Examples of the cellulose derivative include cellulose acetate, cyanoethyl cellulose, and the like. Details of each of the polylactic acid-based polymer and the helical chiral polymer (A1) will be described later.

[0081] "Optically active polypeptide (A2)" refers to a polypeptide that has an asymmetric carbon atom and has a bias in the abundance of optical isomers. From the viewpoints of piezoelectricity and strength, the optically active polypeptide (A2) preferably has a β-sheet structure. Examples of the optically active polypeptide (A2) include animal proteins having optical activity. Examples of the animal protein include fibroin, spider silk protein, etc. Fibers made of animal protein include silk, spider silk, etc. Details of the animal protein will be described later.

[0082] Among them, from the viewpoints of good piezoelectric properties, processability, easy availability, etc., the organic piezoelectric material preferably contains an optically active polymer (A), particularly a helical chiral polymer (A1) or an optically active polypeptide (A2). Further, the helical chiral polymer (A1) preferably contains a polylactic acid-based polymer. The optically active polypeptide (A2) preferably contains an animal protein. Each of the polylactic acid-based polymer and the optically active polypeptide (A2) is non-pyroelectric. By including the polylactic acid-based polymer or the optically active polypeptide (A2) in the organic piezoelectric material, the first piezoelectric sensor 10A has better stability of piezoelectric sensitivity and stability of piezoelectric output (stability against changes over time or temperature) compared to a piezoelectric sensor using pyroelectric PVDF. Also, the optically active polypeptide (A2) is excellent in hydrolysis resistance in a high-temperature and high-humidity environment. The first piezoelectric sensor 10A containing the optically active polypeptide (A2) suppresses a decrease in the first voltage, particularly in a high-temperature and high-humidity environment, compared to, for example, the first piezoelectric sensor 10A containing a polylactic acid-based polymer. Details of the helical chiral polymer (A) will be described later.

[0083] When the optically active polymer (A) is in a fiber shape, the shape of the first long organic piezoelectric body 121 may be a fiber shape or a ribbon shape. When the optically active polymer (A) is in a fiber shape and the shape of the first long organic piezoelectric body 121 is a fiber shape, the organic piezoelectric material may consist only of the optically active polymer (A). When the optically active polymer (A) is in a fibrous shape and the shape of the first long organic piezoelectric body 121 is a ribbon shape, the organic piezoelectric material may contain the optically active polymer (A) and a resin. In this case, the organic piezoelectric material can be formed into a ribbon shape by the resin. When the organic piezoelectric material contains a plurality of fibrous polymer materials (A), each of the plurality of optically active polymers (A) may be joined by the resin. The resin includes at least one of a thermoplastic resin and a thermosetting resin. Examples of the thermoplastic resin include polymethacrylic resins, polyacrylic resins, aromatic polyether ketones, polyarylene resins, etc. Examples of the polymethacrylic resin include polymethacrylic resins, polyolefin resins, methyl polymethacrylate resins, etc. Examples of the polyacrylic resin include methyl polyacrylate resins, etc. Examples of the aromatic polyether ketone include polystyrene resins, polyvinyl acetal resins, polycarbonate resins, polyphenylene ether resins, etc. Examples of the polyarylene resin include polyphenylene oxide resins, polyphenylene sulfide (PPS) resins, etc. These thermoplastic resins may be used alone or in combination of two or more. Examples of the thermosetting resin include epoxy resins, phenol resins, unsaturated polyester resins, thermosetting polyimide resins, bismaleimide triazine resins, benzoxazine resins, etc. These thermosetting resins may be used alone or in combination of two or more.

[0084] The first long organic piezoelectric body 121 preferably has a first composition. In the first composition, the organic piezoelectric material contains the optically active polymer (A), the length direction of the first long organic piezoelectric body 121 and the main orientation direction of the optically active polymer (A) contained in the first long organic piezoelectric body 121 are substantially parallel (the direction parallel to the double arrow D2 in FIG. 5), the orientation degree F of the first long organic piezoelectric body 121 obtained by the following formula (a) from X-ray diffraction measurement is in the range of 0.5 or more and less than 1.0. Orientation degree F = (180° - α) / 180° ··· (a) However, α represents the half-value width of the peak derived from orientation. The unit of α is °.

[0085] The orientation degree F of the first long-strip-shaped organic piezoelectric body 121 is an index indicating the degree of orientation of the optically active polymer (A) contained in the first long-strip-shaped organic piezoelectric body 121. The orientation degree F of the first long-strip-shaped organic piezoelectric body 121 is, for example, the c-axis orientation degree measured by a wide-angle X-ray diffractometer (RINT2550 manufactured by Rigaku Corporation, accessory device: rotating sample stage, X-ray source: CuKα, output: 40 kV 370 mA, detector: scintillation counter). The orientation degree F of the first long-strip-shaped organic piezoelectric body 121 is preferably 0.50 or more and 0.99 or less, more preferably 0.70 or more and 0.98 or less, and particularly preferably 0.80 or more and 0.97 or less. In the first long-strip-shaped organic piezoelectric body 121, the fact that the length direction of the first long-strip-shaped organic piezoelectric body 121 and the main orientation direction of the optically active polymer (A) contained in the first long-strip-shaped organic piezoelectric body 121 are substantially parallel also contributes to the manifestation of piezoelectricity. The fact that the length direction of the first long-strip-shaped organic piezoelectric body 121 and the main orientation direction of the optically active polymer (A) contained in the first long-strip-shaped organic piezoelectric body 121 are substantially parallel also has the advantage that the first long-strip-shaped organic piezoelectric body 121 is excellent in tensile strength in its length direction. Therefore, when the first long-strip-shaped organic piezoelectric body 121 is spirally wound around the first internal conductor 11A, the first long-strip-shaped organic piezoelectric body 121 is not easily broken.

[0086] "Substantially parallel" means that the angle formed by two line segments is 0° or more and less than 30°. The angle formed by the two line segments is preferably 0° or more and 22.5° or less, more preferably 0° or more and 10° or less, still more preferably 0° or more and 5° or less, and particularly preferably 0° or more and 3° or less. For example, when the organic piezoelectric material includes silk or spider silk, which is an example of a fiber made of an animal protein, in the process of producing silk or spider silk, the longitudinal direction of the silk or spider silk and the main orientation direction of the optically active polypeptide (A2) (for example, fibroin or spider silk protein, which is an example of an animal protein) are substantially parallel.

[0087] The main orientation direction of the optically active polymer (A) means the main orientation direction of the optically active polymer (A). The main orientation direction of the optically active polymer (A) can be confirmed, for example, by measuring the orientation degree F of the first elongated organic piezoelectric body 121. When the first elongated organic piezoelectric body 121 is manufactured by stretching a film and forming slits in the stretched film, the main orientation direction of the optically active polymer (A) in the first elongated organic piezoelectric body 121 means the main stretching direction. Here, the main stretching direction refers to the stretching direction in the case of uniaxial stretching, and in the case of biaxial stretching, it refers to the stretching direction with a higher stretching ratio.

[0088] Hereinafter, the case where the first elongated organic piezoelectric body 121 has the first composition and the optically active polymer (A) is the helical chiral polymer (A1) will be described.

[0089] The manufacturing method of the first elongated organic piezoelectric body 121 includes, for example, a method of forming a raw material (for example, the optically active polymer (A)) into a film shape to obtain an unstretched film, subjecting the obtained unstretched film to stretching and crystallization, and slitting the obtained organic piezoelectric film. Here, "slitting" means cutting the organic piezoelectric film into an elongated shape. Note that stretching and crystallization may be performed in any order. Also, a method of sequentially performing pre-crystallization, stretching, and crystallization (annealing) on the unstretched film may be used. The stretching may be uniaxial stretching or biaxial stretching. In the case of biaxial stretching, preferably, the stretching ratio in one direction (the main stretching direction) is increased. Regarding the manufacturing method of the organic piezoelectric film, known documents such as Japanese Patent No. 4934235, International Publication No. 2010 / 104196, International Publication No. 2013 / 054918, International Publication No. 2013 / 089148, etc. can be appropriately referred to. The first long organic piezoelectric body 121 will be described later.

[0090] [First Configuration of the First Piezoelectric Body] Next, with reference to FIGS. 7 and 8, the first configuration A of the first piezoelectric body 12A will be described.

[0091] In the first configuration A, as shown in FIG. 7, the first long organic piezoelectric body 121 is wound in the left direction (left-handed, i.e., counterclockwise) toward the direction D1. Specifically, along the outer peripheral surface of the first internal conductor 11A, it is spirally wound in the first spiral direction D2 toward the direction D1 at the first spiral angle β1 without a gap. This wound first long organic piezoelectric body 121 constitutes the first piezoelectric body 12A. The "spiral angle β1" means the angle formed by the axial direction AX of the first internal conductor 11A and the arrangement direction of the first long organic piezoelectric body 121 with respect to the axial direction AX of the first internal conductor 11A. The spiral angle β1 is preferably 15° or more and 75° or less (45° ± 30°), more preferably 35° or more and 55° or less (45° ± 10°). The "first spiral direction D2" refers to the direction in which the first long organic piezoelectric body 121 is wound toward the direction D1.

[0092] Next, the operation of the first configuration A will be described. For example, when tension (stress) acts in a direction parallel to the axial direction AX on the first piezoelectric sensor 10A, if shear strain is applied to the helical chiral polymer (A1) contained in the first elongated organic piezoelectric body 121, polarization of the helical chiral polymer (A1) occurs in the radial direction of the first piezoelectric sensor 10A. This polarization direction is such that when the first piezoelectric body 12A of the first configuration A in which the first elongated organic piezoelectric body 121 is helically wound is regarded as an aggregate of minute regions that can be regarded as a plane with respect to the axial direction AX, when a shear force due to tension (stress) acts on the helical chiral polymer (A1) in the plane of the minute regions that make it up, it is substantially in agreement with the direction of the electric field generated due to the piezoelectric constant d 14 Specifically, the polarization of the helical chiral polymer (A1) occurs in the radial direction of the first piezoelectric sensor 10A as indicated by the arrow in FIG. 8, and it is considered that the polarization directions are in phase. Thereby, the first piezoelectric sensor 10A can effectively generate a first voltage proportional to the external force F more easily. From the above, when the first piezoelectric body 12A is of the first configuration A, the first piezoelectric sensor 10A has excellent piezoelectric sensitivity and excellent stability of piezoelectric output.

[0093] In the first configuration A, when the helical chiral polymer (A1) is PLLA, when tension acts on the first piezoelectric sensor 10A in a direction parallel to the axial direction AX, an electric field (polarization) is generated in the outer direction from the center of a circle with a circular cross section perpendicular to the tension, parallel to the radial direction. That is, the sign of the first voltage becomes positive. In the first configuration A, when the helical chiral polymer (A1) is PLLA, when pressure acts on the first piezoelectric sensor 10A in a direction parallel to the axial direction AX, an electric field (polarization) is generated in the direction from the outside to the center of a circle with a circular cross section perpendicular to the pressure, parallel to the radial direction. That is, the sign of the first voltage becomes negative.

[0094] In the first configuration A, when the helical chiral polymer (A1) is PDLA, the sign of the first voltage is opposite to that when the helical chiral polymer (A1) is PLLA. Specifically, in the first configuration A, when the helical chiral polymer (A1) is PDLA and a tensile force acts on the first piezoelectric sensor 10A in a direction parallel to the axial direction AX, an electric field (polarization) is generated from the outside to the center of a circle with a circular cross-section parallel to the radial direction and perpendicular to the tensile force. That is, the sign of the first voltage becomes negative. In the first configuration A, when the helical chiral polymer (A1) is PDLA and a compressive force acts on the first piezoelectric sensor 10A in a direction parallel to the axial direction AX, an electric field (polarization) is generated from the center to the outside of a circle with a circular cross-section parallel to the radial direction and perpendicular to the compressive force. That is, the sign of the first voltage becomes positive.

[0095] Also, in the first configuration A, although the first elongated organic piezoelectric body 121 is wound counterclockwise in the direction D1, the configuration of the first piezoelectric body 12A may be such that the first elongated organic piezoelectric body 121 is wound clockwise in the direction D1 (hereinafter referred to as "the first configuration A'").

[0096] In the first configuration A', when the helical chiral polymer (A1) is PLLA, the sign of the first voltage is opposite to that when the helical chiral polymer (A1) in the first configuration A is PLLA. Specifically, in the first configuration A', when the helical chiral polymer (A1) is PLLA and a tensile force acts on the first piezoelectric sensor 10A in a direction parallel to the axial direction AX, an electric field (polarization) is generated from the outside to the center of a circle with a circular cross-section parallel to the radial direction and perpendicular to the tensile force. That is, the sign of the first voltage becomes negative. In the first configuration A', when the helical chiral polymer (A1) is PLLA and a compressive force acts on the first piezoelectric sensor 10A in a direction parallel to the axial direction AX, an electric field (polarization) is generated from the center to the outside of a circle with a circular cross-section parallel to the radial direction and perpendicular to the compressive force. That is, the sign of the first voltage becomes positive.

[0097] In the first configuration A', when the helical chiral polymer (A1) is PDLA, the sign of the first voltage is opposite to that when the helical chiral polymer (A1) in the first configuration A is PDLA. Specifically, in the first configuration A', when the helical chiral polymer (A1) is PDLA and a tensile force acts on the first piezoelectric sensor 10A, an electric field (polarization) is generated in the radial direction, parallel to the tensile force and from the center of the circle of the circular cross-section perpendicular to the tensile force toward the outer direction. That is, the sign of the first voltage becomes positive. In the first configuration A', when the helical chiral polymer (A1) is PDLA and a compressive force acts on the first piezoelectric sensor 10A, an electric field (polarization) is generated in the radial direction, parallel to the compressive force and from the outer side of the circle of the circular cross-section toward the center direction. That is, the sign of the first voltage becomes negative.

[0098] (Second long organic piezoelectric body) The second long organic piezoelectric body 122 is made of an organic piezoelectric material and has a piezoelectric constant d 14 having it.

[0099] Whether the "second long organic piezoelectric body 122 has a piezoelectric constant d 14 having it" is determined, for example, by the first determination method described above.

[0100] The second long organic piezoelectric body 122 is a long object. Each of the shape, width, thickness, ratio [width / thickness], cross-sectional shape, and major axis diameter of the second long organic piezoelectric body 122 is the same as those exemplified for the first long organic piezoelectric body 121. Each of the width, thickness, and ratio [width / thickness] of the second long organic piezoelectric body 122 may be the same as or different from the width, thickness, and ratio [width / thickness] of the first long organic piezoelectric body 121.

[0101] Examples of the organic piezoelectric material of the second long organic piezoelectric body 122 include the same materials as those exemplified as the organic piezoelectric material of the first long organic piezoelectric body 121. The organic piezoelectric material of the second long organic piezoelectric body 122 may be the same as or different from the organic piezoelectric material of the first long organic piezoelectric body 121.

[0102] The second long organic piezoelectric body 122 preferably has the following second composition. In the second composition, the organic piezoelectric material contains an optically active polymer (A), The length direction of the second long-strip-shaped organic piezoelectric body 122 and the main alignment direction of the optically active polymer (A) contained in the second long-strip-shaped organic piezoelectric body 122 are substantially parallel. The degree of orientation F of the second long-strip-shaped organic piezoelectric body 122 obtained by the above formula (a) from X-ray diffraction measurement is in the range of 0.5 or more and less than 1.0.

[0103] The degree of orientation F of the second long-strip-shaped organic piezoelectric body 122 is an index indicating the degree of orientation of the optically active polymer (A) contained in the second long-strip-shaped organic piezoelectric body 122. "Substantially parallel" means that the angle formed by two line segments is 0° or more and less than 30°. The angle formed by the two line segments is preferably 0° or more and 22.5° or less, more preferably 0° or more and 10° or less, still more preferably 0° or more and 5° or less, and particularly preferably 0° or more and 3° or less.

[0104] Hereinafter, the case where the organic piezoelectric material of the second long-strip-shaped organic piezoelectric body 122 has a second composition and the optically active polymer (A) is a helical chiral polymer (A1) will be described.

[0105] Examples of the manufacturing method of the second long-strip-shaped organic piezoelectric body 122 include the same manufacturing methods as those exemplified as the manufacturing method of the first long-strip-shaped organic piezoelectric body 121. The second long-strip-shaped organic piezoelectric body 122 will be described later.

[0106] [Second Configuration of the First Piezoelectric Body] Next, with reference to FIG. 9, the second configuration A of the first piezoelectric body 12A will be described.

[0107] The second configuration A of the first piezoelectric body 12A is different from the first configuration A of the first piezoelectric body 12A in that it includes the second long-strip-shaped organic piezoelectric body 122. Specifically, as shown in FIG. 9, the second configuration A of the first piezoelectric body 12A includes the first long-strip-shaped organic piezoelectric body 121 and the second long-strip-shaped organic piezoelectric body 122. In the second configuration A, similar to the first configuration A, the first long organic piezoelectric body 121 is spirally wound along the outer peripheral surface of the first internal conductor 11A in the first spiral direction D2 without a gap toward the direction D1 at a spiral angle β1. That is, the first long organic piezoelectric body 121 is wound in the left direction (left-handed, i.e., counterclockwise) toward the direction D1. In the second configuration A, as shown in FIG. 9, the second long organic piezoelectric body 122 is spirally wound along the outer peripheral surface of the first long organic piezoelectric body 121 at a spiral angle β2 in a direction opposite to the winding direction of the first long organic piezoelectric body 121. The "spiral angle β2" has the same meaning as the aforementioned spiral angle β1. The spiral angle β2 is substantially the same angle as the spiral angle β1. Also, in FIG. 9, the main alignment direction of the helical chiral polymer (A1) included in the second long organic piezoelectric body 122 is indicated by the double arrow D3. That is, the main alignment direction of the helical chiral polymer (A1) included in the second long organic piezoelectric body 122 and the arrangement direction of the second long organic piezoelectric body 122 (the length direction of the second long organic piezoelectric body 122) are substantially parallel. It is preferable that the chirality of the helical chiral polymer (A1) included in the first long organic piezoelectric body 121 is different from the chirality of the helical chiral polymer (A1) included in the second long organic piezoelectric body 122 outside the body. Thereby, for example, when a tension in the axial direction AX acts on the first piezoelectric sensor 10A, polarization occurs in both the helical chiral polymer (A1) included in the first long organic piezoelectric body 121 and the helical chiral polymer (A1) included in the second long organic piezoelectric body 122. The polarization direction is in the radial direction of the first piezoelectric sensor 10A in both cases. As a result, a voltage signal (charge signal) due to the tension applied to the second piezoelectric sensor 10B corresponding to the tension applied to the first piezoelectric sensor 10A is detected. Therefore, the voltage signal due to the pressure and vibration received by the first piezoelectric sensor 10A and the voltage signal due to the vibration received by the corresponding second piezoelectric sensor 10B are detected.

[0108] Hereinafter, the operation of the first piezoelectric sensor 10A of the second configuration A will be described. For example, when tension is applied in a direction parallel to the direction D1 of the first piezoelectric sensor 10A, shear stress acts on both the helical chiral polymer (A1) contained in the first elongated organic piezoelectric body 121 and the helical chiral polymer (A1) contained in the second elongated organic piezoelectric body 122, and polarization occurs. The polarization direction is the radial direction of the first piezoelectric sensor 10A in both cases. As a result, a voltage signal proportional to the tension is effectively detected. From the above, according to the first piezoelectric sensor 10A of the second configuration A, the piezoelectric sensitivity and the stability of the piezoelectric output are improved compared to the first piezoelectric sensor 10A of the first configuration A. In particular, since the first piezoelectric body 12A includes the first elongated organic piezoelectric body 121 and the second elongated organic piezoelectric body 122 and has a two-layer structure, there are fewer gaps between the first elongated organic piezoelectric body 121 and the second elongated organic piezoelectric body 122 and they can be closely adhered to the first internal conductor 11A and the first external conductor 13A, and the electric field generated by the tension is easily transmitted to the first internal conductor 11A efficiently. Therefore, the first piezoelectric sensor 10A of the second configuration A can detect an external force with higher sensitivity.

[0109] [Third Configuration of the First Piezoelectric Body] Next, with reference to FIG. 10, the third configuration A of the first piezoelectric body 12A will be described.

[0110] The third configuration A of the first piezoelectric body 12A is different from the first piezoelectric sensor 10A of the second configuration A of the first piezoelectric body 12A in that it has a braided structure. Specifically, as shown in FIG. 10, the third configuration A of the first piezoelectric body 12A includes a first elongated organic piezoelectric body 121 and a second elongated organic piezoelectric body 122. In the third configuration A, the first elongated organic piezoelectric body 121 is wound helically to the left at a helical angle β1 with respect to the axial direction AX of the first internal conductor 11A, and the second elongated organic piezoelectric body 122 is wound helically to the right at a helical angle β2, and the first elongated organic piezoelectric body 121 and the second elongated organic piezoelectric body 122 are alternately crossed. The axial direction AX of the first internal conductor 11A and the direction D1 are in a substantially parallel relationship.

[0111] "Substantially parallel" means that the angle formed by two line segments is 0° or more and less than 30°. The angle formed by the two line segments is preferably 0° or more and 22.5° or less, more preferably 0° or more and 10° or less, still more preferably 0° or more and 5° or less, and particularly preferably 0° or more and 3° or less. In the lacing structure shown in FIG. 10, the main alignment direction (double arrow D2) of the helical chiral polymer (A1) contained in the first elongated organic piezoelectric body 121 and the arrangement direction of the first elongated organic piezoelectric body 121 are substantially parallel. Similarly, the main alignment direction (double arrow D2) of the helical chiral polymer (A1) contained in the second elongated organic piezoelectric body 122 and the arrangement direction of the second elongated organic piezoelectric body 122 are substantially parallel. The chirality of the helical chiral polymer (A1) contained in the first elongated organic piezoelectric body 121 and the chirality of the helical chiral polymer (A1) contained in the second elongated organic piezoelectric body 122 are preferably different from each other. Thereby, for example, when a tensile force in the axial direction AX acts on the first piezoelectric sensor 10A, polarization occurs in both the helical chiral polymer (A1) contained in the first elongated organic piezoelectric body 121 and the helical chiral polymer (A1) contained in the second elongated organic piezoelectric body 122. The polarization directions are both in the radial direction of the first piezoelectric sensor 10A. As a result, a voltage signal proportional to the tensile force is detected more effectively. As a result, the piezoelectric sensitivity and the stability of the piezoelectric output are further improved.

[0112] Hereinafter, the operation of the first piezoelectric sensor 10A of the third configuration A will be described. For example, when a tensile force in the axial direction AX acts on the first piezoelectric sensor 10A, polarization occurs in both the helical chiral polymer (A1) contained in the first elongated organic piezoelectric body 121 and the helical chiral polymer (A1) contained in the second elongated organic piezoelectric body 122. The polarization directions are both in the radial direction of the first piezoelectric sensor 10A. As a result, a voltage signal proportional to the tensile force is effectively detected. From the above, the first piezoelectric sensor 10A of the third configuration A can detect the external force applied to the first piezoelectric body 12A with higher sensitivity.

[0113] (Sheet-like piezoelectric body) The sheet-shaped piezoelectric body is made of a piezoelectric material and has piezoelectric constants d 33 and piezoelectric constant d 31 but does not have piezoelectric constant d 14 .

[0114] Whether the "sheet-shaped piezoelectric body has piezoelectric constants d 33 and piezoelectric constant d 31 but does not have piezoelectric constant d 14 " is determined by the following second determination method. In the second determination method, a first piezoelectric sensor 10A in which the first piezoelectric body 12A is the fourth configuration A described later (hereinafter sometimes referred to as "the first piezoelectric sensor 10A of the fourth configuration A"), a second piezoelectric sensor 10B in which the second piezoelectric body 12B is the fourth configuration B described later (hereinafter sometimes referred to as "the second piezoelectric sensor 10B of the fourth configuration B"), and a voltmeter are used.

[0115] Specifically, in the second determination method, the first piezoelectric sensor 10A of the fourth configuration A and the second piezoelectric sensor 10B of the fourth configuration B are manufactured. The first internal conductor 11A of the first piezoelectric sensor 10A of the fourth configuration A and the first external conductor 13A of the first piezoelectric sensor 10A of the fourth configuration A are electrically connected to the voltmeter. Then, a predetermined external force F is applied to the first piezoelectric sensor 10A of the fourth configuration A to detect a determination voltage. Similarly, the first internal conductor 11A of the second piezoelectric sensor 10B of the fourth configuration B and the first external conductor 13A of the second piezoelectric sensor 10B of the fourth configuration B are electrically connected to the voltmeter. Then, the same external force F as the external force F applied to the first piezoelectric sensor 10A of the fourth configuration A is applied to the second piezoelectric sensor 10B of the fourth configuration B to detect a determination voltage.

[0116] In the second determination method, when the following condition (Y) is satisfied, it is determined that it corresponds to "the sheet-shaped piezoelectric body has piezoelectric constants d 33 and piezoelectric constant d 31 but does not have piezoelectric constant d 14 ". On the other hand, when the following condition (Y) is not satisfied, "the sheet-shaped piezoelectric body has piezoelectric constants d 33 and piezoelectric constant d 31 but does not have piezoelectric constant d 14It is determined that it does not correspond to "having none". (Y) The polarity of the determination voltage of the first piezoelectric sensor 10A of the fourth configuration A and the polarity of the determination voltage of the second piezoelectric sensor 10B of the fourth configuration B are opposite.

[0117] The sheet-shaped piezoelectric body is sheet-shaped. The thickness of the sheet-shaped piezoelectric body is preferably 0.001 mm or more and 0.2 mm or less. By having a thickness of 0.001 mm or more, the strength of the sheet-shaped piezoelectric body is ensured. Further, by having a thickness of 0.2 mm or less, the degree of freedom (flexibility) of non-plastic deformation in the thickness direction of the sheet-shaped piezoelectric body is improved.

[0118] The piezoelectric material is such that the sheet-shaped piezoelectric body has piezoelectric constants d 33 and piezoelectric constant d 31 and does not have piezoelectric constant d 14 Any material can be used as long as it has this property, and examples include organic piezoelectric materials and inorganic piezoelectric materials. The organic piezoelectric material may be a low-molecular material or a high-molecular material. Examples of the organic piezoelectric material include at least one selected from the group consisting of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyvinyl fluoride (PVF), polychlorotrifluoroethylene (PCTFE), ethyl trifluoroacetate (EFA), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), chlorotrifluoroethylene-ethylene copolymer (ETFE), chlorotrifluoroethylene-ethylene copolymer (ECTFE), poly(vinylidene fluoride / hexafluoropropylene) copolymer (PVDF-HFP), and poly(vinylidene fluoride / trifluoroethylene). Examples of the inorganic piezoelectric material include materials obtained by molding powders of inorganic ceramic piezoelectric materials such as lead zirconate titanate (PZT)-based materials into a sheet shape using a polymer. Among them, from the viewpoints of light weight, high flexibility, and excellent processability, etc., it is preferable that the piezoelectric material contains PVDF.

[0119] Next, the case where the piezoelectric material is made of PVDF will be described.

[0120] Examples of the method for manufacturing the sheet-shaped piezoelectric body include a method in which a raw material (PVDF) is formed into a sheet shape, subjected to a stretching treatment to obtain a stretched sheet, and the obtained stretched sheet is subjected to a poling treatment. In the poling treatment, for example, while heating the stretched sheet, a positive voltage is applied to one surface of the stretched sheet, and a negative voltage is applied to the other surface of the stretched sheet. As a result, in the film thickness direction of the stretched sheet, a dipole moment is formed from one surface of the stretched sheet toward the other surface due to the difference in the electrical attractiveness of fluorine atoms and carbon atoms. That is, the sheet-shaped piezoelectric body has spontaneous polarization.

[0121] [Fourth Configuration of the First Piezoelectric Body] Next, the fourth configuration A of the first piezoelectric body 12A will be described.

[0122] In the fourth configuration A, the sheet-shaped piezoelectric body is wound into a cylindrical shape along the outer peripheral surface of the first internal conductor 11A such that the polymer chains of PVDF are oriented along the axial direction AX. One surface of the sheet-shaped piezoelectric body is on the side of the first internal conductor 11A. This wound sheet-shaped piezoelectric body constitutes the first piezoelectric body 12A. "The polymer chains of PVDF are oriented along the axial direction AX" means that the stretching direction in the stretching process of the manufacturing process of the sheet-shaped piezoelectric body and the axial direction AX are parallel.

[0123] Next, the operation of the fourth configuration A will be described. For example, when an external force acts on the first piezoelectric sensor 10A and the first piezoelectric body 12A contracts, an electric field (polarization) from the center of the circle with a circular cross-section toward the outer side direction is generated in parallel with the radial direction. That is, the positive and negative of the first voltage become positive. For example, when an external force acts on the first piezoelectric sensor 10A and the first piezoelectric body 12A extends, an electric field (polarization) from the outer side to the center direction of the circle with a circular cross-section is generated in parallel with the radial direction. That is, the positive and negative of the first voltage become negative.

[0124] <Adhesive layer> The first piezoelectric sensor 10A may have an adhesive layer. The adhesive layer is disposed, for example, between the first internal conductor 11A and the first piezoelectric body 12A. Thereby, even when a tension caused by an external force acts on the first piezoelectric sensor 10A in the axial direction AX of the internal conductor 11A, the occurrence of displacement of the relative positions of the first piezoelectric body 12A and the first internal conductor 11A can be suppressed. The axial direction AX and the direction D1 are parallel. Further, the first long organic piezoelectric body 121 is more likely to be acted on by a tension caused by an external force. Examples of the material of the adhesive for forming the adhesive layer include epoxy adhesives, urethane adhesives, vinyl acetate resin emulsion adhesives, ethylene vinyl acetate (EVA) emulsion adhesives, acrylic resin emulsion adhesives, styrene-butadiene rubber latex adhesives, silicone resin adhesives, α-olefin (isobutene-maleic anhydride resin) adhesives, vinyl chloride resin solvent adhesives, rubber adhesives, elastic adhesives, chloroprene rubber solvent adhesives, nitrile rubber solvent adhesives, etc., and cyanoacrylate adhesives.

[0125] <First insulator> The first piezoelectric sensor 10A may have a first insulator. The first insulator is disposed, for example, at least one of between the first piezoelectric body 12A and the first internal conductor 11A and between the first piezoelectric body 12A and the first external conductor 13A. Thereby, the occurrence of a short circuit between the first internal conductor 11A and the first external conductor 13A can be further suppressed. The first insulator is formed, for example, by winding a long object spirally along the outer peripheral surface of the first internal conductor 11A. As the material of the first insulator, any material having electrical insulation properties may be used. For example, vinyl chloride resin, polyethylene resin, polypropylene resin, ethylene tetrafluoroethylene copolymer (ETFE), tetrafluoroethylene hexafluoropropylene copolymer (FEP), tetrafluoroethylene resin (PTFE), tetrafluoroethylene perfluoropropyl vinyl ether copolymer (PFA), fluororubber, polyester resin, polyimide resin, polyamide resin, polyethylene terephthalate resin (PET), rubber (including elastomers), etc. can be mentioned.

[0126] <Second insulator> The first piezoelectric sensor 10A may have a second insulator. The second insulator is disposed on the outer periphery of the first external conductor 13A. The second insulator may cover the entire outer periphery of the first external conductor 13A. Thereby, it becomes possible to electrostatically shield the first internal conductor 11A, and it is possible to suppress a voltage change of the first voltage due to the influence of external static electricity. The material of the second insulator may be any material having electrical insulation properties, and examples thereof include the same materials as those exemplified as the material of the first insulator.

[0127] <Functional layer> The first piezoelectric sensor 10A may have a functional layer. The functional layer is disposed, for example, at least between the first piezoelectric body 12A and the first internal conductor 11A and between the first piezoelectric body 12A and the first external conductor 13A. Examples of the layer constituting the functional layer (hereinafter referred to as "constituent layer") include an easy adhesion layer, a hard coat layer, a refractive index adjustment layer, an anti-reflection layer, an anti-glare layer, a lubricity imparting layer, an anti-blocking layer, a protective layer, an adhesive layer, an antistatic layer, a heat dissipation layer, an ultraviolet absorption layer, an anti-Newton ring layer, a light scattering layer, a polarizing layer, a gas barrier layer, a hue adjustment layer, an electrode layer, etc. The functional layer may have a single-layer structure composed of a single layer of the constituent layer, or may have a multiple-layer structure composed of two or more constituent layers. When the functional layer has a multiple-layer structure, each of the multiple constituent layers may be the same constituent layer or different constituent layers. When the first piezoelectric sensor 10A has a functional layer between the first piezoelectric body 12A and the first internal conductor 11A and between the first piezoelectric body 12A and the first external conductor 13A, the functional layer between the first piezoelectric body 12A and the first internal conductor 11A and the functional layer between the first piezoelectric body 12A and the first external conductor 13A may be the same or different. The film thickness of the functional layer is not particularly limited, and a range of 0.01 μm or more and 10 μm or less is preferable. The material of the functional layer is appropriately selected according to the functions required for the functional layer. Examples include inorganic substances such as metals and metal oxides; organic substances such as resins; composite compositions containing resins and fine particles; and the like. Examples of the resin include cured products obtained by curing with temperature or active energy rays.

[0128] (Helical chiral polymer (A1)) Next, the helical chiral polymer (A1) will be described.

[0129] From the viewpoint of further improving the piezoelectricity, the helical chiral polymer (A1) preferably has an optical purity of 95.00% ee or more. From the viewpoint of further improving the piezoelectricity, the helical chiral polymer (A1) preferably consists of the D-form or the L-form. From the viewpoint of further improving the piezoelectricity, the content of the helical chiral polymer (A1) is preferably 80% by mass or more based on the total amount of the first long-chain organic piezoelectric body 121.

[0130] The optical purity of the helical chiral polymer (A1) is preferably 95.00% ee or more, more preferably 96.00% ee or more, still more preferably 99.00% ee or more, particularly preferably 99.99% ee or more, and desirably 100.00% ee, from the viewpoint of improving the piezoelectric properties of the first long-chain organic piezoelectric body 121. By setting the optical purity of the helical chiral polymer (A1) within the above range, the packing property of the polymer crystal exhibiting piezoelectric properties is increased, and as a result, it is considered that the piezoelectric properties are enhanced.

[0131] The optical purity of the helical chiral polymer (A1) is a value calculated by the following formula. Optical purity (%ee) = 100 × |L amount - D amount| / (L amount + D amount) That is, the optical purity of the helical chiral polymer (A1) is The value obtained by multiplying 100 by the value obtained by dividing (dividing) the "difference in amount (absolute value) between the amount [mass%] of the L-form of the helical chiral polymer (A1) and the amount [mass%] of the D-form of the helical chiral polymer (A1)" by the "total amount of the amount [mass%] of the L-form of the helical chiral polymer (A1) and the amount [mass%] of the D-form of the helical chiral polymer (A1)".

[0132] Note that the amount [mass%] of the L-form of the helical chiral polymer (A1) and the amount [mass%] of the D-form of the helical chiral polymer (A1) are values obtained by a method using high performance liquid chromatography (HPLC). Specific details of the measurement will be described later.

[0133] - Weight average molecular weight - The weight average molecular weight (Mw) of the helical chiral polymer (A1) is preferably 50,000 or more and 1,000,000 or less. When the Mw of the helical chiral polymer (A1) is 50,000 or more, the mechanical strength of the first long-chain organic piezoelectric body 121 and the second long-chain organic piezoelectric body 122 (hereinafter sometimes collectively referred to as "the first long-chain organic piezoelectric body 121 etc.") is improved. The above Mw is preferably 100,000 or more, and more preferably 200,000 or more. When the Mw of the helical chiral polymer (A1) is 1,000,000 or less, the moldability is improved when obtaining the first long organic piezoelectric body 121 or the like by molding (for example, extrusion molding, melt spinning). The Mw of the helical chiral polymer (A1) is preferably 800,000 or less, and more preferably 300,000 or less.

[0134] From the viewpoint of the strength of the first long organic piezoelectric body 121 or the like, the molecular weight distribution (Mw / Mn) of the helical chiral polymer (A1) is preferably 1.1 or more and 5 or less, and more preferably 1.2 or more and 4 or less. Further, it is preferably 1.4 or more and 3 or less.

[0135] The weight average molecular weight (Mw) and the molecular weight distribution (Mw / Mn) of the helical chiral polymer (A1) refer to the values measured using gel permeation chromatography (GPC). Here, Mn is the number average molecular weight of the helical chiral polymer (A1). Hereinafter, an example of a method for measuring Mw and Mw / Mn of the helical chiral polymer (A1) by GPC is shown.

[0136] -GPC measuring device- GPC-100 manufactured by Waters -Column- Shodex LF-804 manufactured by Showa Denko KK -Sample preparation- The first long organic piezoelectric body 121 or the like is dissolved in a solvent (for example, chloroform) at 40°C to prepare a sample solution with a concentration of 1 mg / ml. -Measurement conditions- 0.1 ml of the sample solution is introduced into the column at a flow rate of 1 ml / min with a solvent [chloroform] at a temperature of 40°C.

[0137] The sample concentration in the sample solution separated by the column is measured with a differential refractometer. A universal calibration curve is prepared using a polystyrene standard sample, and the weight average molecular weight (Mw) and the molecular weight distribution (Mw / Mn) of the helical chiral polymer (A1) are calculated.

[0138] As the polylactic acid-based polymer which is an example of the helical chiral polymer (A1), commercially available polylactic acid can be used. Examples of commercially available products include, for example, PURASORB (PD, PL) manufactured by PURAC, LACEA (H-100, H-400) manufactured by Mitsui Chemicals, and Ingeo TM biopolymer, etc. manufactured by NatureWorks LLC. When using a polylactic acid-based polymer as the helical chiral polymer (A1), in order to make the weight average molecular weight (Mw) of the polylactic acid-based polymer 50,000 or more, it is preferable to produce the polylactic acid-based polymer by the lactide method or the direct polymerization method.

[0139] The first long organic piezoelectric body 121 or the like may contain only one kind of the helical chiral polymer (A1) or may contain two or more kinds. The content of the helical chiral polymer (A1) in the first long organic piezoelectric body 121 or the like (total content in the case of two or more kinds) is preferably 80% by mass or more based on the total amount of the first long organic piezoelectric body 121.

[0140] (Polylactic acid-based polymer) Next, the polylactic acid-based polymer will be described.

[0141] As the polylactic acid-based polymer, from the viewpoint of increasing the optical purity and improving the piezoelectricity, it preferably has a main chain containing a repeating unit represented by the following formula (1).

[0142]

Chemical formula

[0143] The polylactic acid-based polymer refers to "a polymer composed only of repeating units derived from monomers selected from polylactic acid (L-lactic acid and D-lactic acid)", "a copolymer of L-lactic acid or D-lactic acid and a compound copolymerizable with the L-lactic acid or D-lactic acid", or a mixture of both. Among polylactic acid-based polymers, polylactic acid is preferred, and PLLA or PDLA is most preferred.

[0144] Polylactic acid is a polymer in which lactic acid is polymerized by an ester bond to form a long chain. Examples of the method for producing polylactic acid include the lactide method via lactide; the direct polymerization method in which lactic acid is heated under reduced pressure in a solvent and polymerized while removing water. Examples of polylactic acid include block copolymers and graft copolymers. The block copolymer includes a homopolymer of L-lactic acid, a homopolymer of D-lactic acid, and a polymer of at least one of L-lactic acid and D-lactic acid. The graft copolymer includes a polymer of at least one of L-lactic acid and D-lactic acid.

[0145] Examples of the "compound copolymerizable with L-lactic acid or D-lactic acid" include hydroxycarboxylic acids such as glycolic acid, dimethylglycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxypropanoic acid, 3-hydroxypropanoic acid, 2-hydroxyvaleric acid, 3-hydroxyvaleric acid, 4-hydroxyvaleric acid, 5-hydroxyvaleric acid, 2-hydroxycaproic acid, 3-hydroxycaproic acid, 4-hydroxycaproic acid, 5-hydroxycaproic acid, 6-hydroxycaproic acid, 6-hydroxymethylcaproic acid, mandelic acid; cyclic esters such as glycolide, β-methyl-δ-valerolactone, γ-valerolactone, ε-caprolactone; polyvalent carboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, terephthalic acid and their anhydrides; polyhydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, tetramethylene glycol, 1,4-hexanedimethanol; polysaccharides such as cellulose; aminocarboxylic acids such as α-amino acid; and the like.

[0146] Examples of the "copolymer of L-lactic acid or D-lactic acid and a compound copolymerizable with the L-lactic acid or D-lactic acid" include block copolymers or graft copolymers having a polylactic acid sequence capable of forming helical crystals.

[0147] The concentration of the structure derived from the copolymer component in the polylactic acid-based polymer is preferably 20 mol% or less. For example, with respect to the total number of moles of the structure derived from lactic acid and the structure derived from a compound copolymerizable with lactic acid (copolymer component) in the polylactic acid-based polymer, the concentration of the structure derived from the copolymer component is preferably 20 mol% or less.

[0148] Examples of the method for producing the polylactic acid-based polymer include a method of directly dehydrating and condensing lactic acid as described in JP-A-59-096123 and JP-A-7-033861; a method of ring-opening polymerization using lactide, which is a cyclic dimer of lactic acid, as described in U.S. Patent No. 2,668,182; and the like.

[0149] Furthermore, in order to make the optical purity of the polylactic acid-based polymer 95.00% ee or more, for example, when producing polylactic acid by the lactide method, it is preferable to polymerize lactide whose optical purity has been improved to 95.00% ee or more by a crystallization operation.

[0150] (Animal protein) Hereinafter, an animal protein, which is an example of the optically active polypeptide (A2), will be described.

[0151] Examples of animal proteins include sericin, collagen, keratin, elastin, etc., in addition to the above-described fibroin and spider silk protein. Among them, the optically active polypeptide (A2) preferably contains at least one of fibroin and spider silk protein, and more particularly preferably consists of at least one of fibroin and spider silk protein.

[0152] The spider silk protein may be a natural spider silk protein or one derived from or similar to a natural spider silk protein (hereinafter, these are collectively referred to as "derived"), and is not particularly limited. "One derived from a natural spider silk protein" means one having an amino acid sequence similar to or the same as the repeating sequence of amino acids of the natural spider silk protein. Examples of "one derived from a natural spider silk protein" include recombinant spider silk proteins, variants of natural spider silk proteins, analogs of natural spider silk proteins, and derivatives of natural spider silk proteins.

[0153] From the viewpoint of excellent toughness, the spider silk protein is preferably a major ampullate spidroin protein produced in the major ampullate gland of a spider or a spider silk protein derived from the major ampullate spidroin protein. Examples of the major ampullate spidroin protein include MaSp1 or MaSp2, which is a major ampullate spidroin derived from Nephila clavipes, and ADF3 or ADF4 derived from Araneus diadematus.

[0154] The spider silk protein may also be a minor ampullate spidroin protein produced in the minor ampullate gland of a spider or a spider silk protein derived from the minor ampullate spidroin protein. Examples of the minor ampullate spidroin protein include MiSp1 and MiSp2, which are minor ampullate spidroins derived from Nephila clavipes.

[0155] In addition, the spider silk protein may also be a flagelliform silk protein produced in the flagelliform gland of a spider or a spider silk protein derived from this flagelliform silk protein. Examples of the cross-thread protein include, for example, flagelliform silk protein derived from Nephila clavipes (American golden orb-weaving spider).

[0156] Examples of the spider silk protein derived from the major ampullate gland spidroin protein described above include, for example, a recombinant spider silk protein containing a unit of the amino acid sequence represented by the following formula (2). The recombinant spider silk protein may contain two or more (preferably four or more, more preferably six or more) units of the amino acid sequence represented by the following formula (2). When the recombinant spider silk protein contains two or more units of the amino acid sequence represented by the following formula (2), the two or more units of the amino acid sequence may be the same or different.

[0157] REP1-REP2 … Formula (2) [In formula (2), REP1 is a polyalanine region mainly composed of alanine and represented by (X1)p, and REP2 is an amino acid sequence consisting of 10 to 200 residues.]

[0158] In formula (2), REP1 is a polyalanine region mainly composed of alanine and represented by (X1)p. Preferably, REP1 is polyalanine. In (X1)p, p is not particularly limited, but preferably represents an integer of 2 to 20, more preferably an integer of 4 to 12. In (X1)p, X1 represents alanine (Ala), serine (Ser), or glycine (Gly). In the polyalanine region represented by (X1)p, it is preferable that the total number of alanine residues is 80% or more (more preferably 85% or more) of the total number of amino acid residues in the polyalanine region. In REP1 in formula (2), the alanines arranged consecutively are preferably two or more residues, more preferably three or more residues, still more preferably four or more residues, and particularly preferably five or more residues. In REP1 in formula (2), the alanines arranged consecutively are preferably 20 residues or less, more preferably 16 residues or less, still more preferably 12 residues or less, and particularly preferably 10 residues or less.

[0159] In formula (2), REP2 is an amino acid sequence consisting of 10 to 200 amino acid residues. The total number of residues of glycine, serine, glutamine, proline, and alanine contained in this amino acid sequence is preferably 40% or more, more preferably 50% or more, and particularly preferably 60% or more based on the total number of the above amino acid residues.

[0160] Examples of the spider silk protein derived from the above-mentioned small spinning duct silk protein include recombinant spider silk proteins containing the amino acid sequence represented by the following formula (3).

[0161] REP3-REP4-REP5 … Formula (3) 〔In formula (3), REP3 is an amino acid sequence represented by (Gly-Gly-Z)m, REP4 is an amino acid sequence represented by (Gly-Ala)l, and REP5 is an amino acid sequence represented by (Ala)r. In REP3, Z means any one amino acid. In REP3, m is 1 to 4, in REP4, l is 0 to 4, and in REP5, r is 1 to 6.〕

[0162] In REP3, Z means any one amino acid, but is preferably one amino acid selected particularly from the group consisting of Ala, Tyr, and Gln.

[0163] The above-mentioned recombinant spider silk proteins (for example, recombinant spider silk proteins containing units of the amino acid sequence represented by formula (2), recombinant spider silk proteins containing the amino acid sequence represented by formula (3), etc.) can be produced using a host transformed with an expression vector containing a gene encoding a natural-type spider silk protein to be recombined.

[0164] The first long-shaped organic piezoelectric body 121 and the like preferably contain fibers made of an optically active polypeptide (A2) from the viewpoint of piezoelectricity. Examples of the fibers made of the optically active polypeptide (A2) include fibers made of an animal protein having optical activity. Examples of the fibers made of an animal protein having optical activity include silk, wool, mohair, cashmere, camel, llama, alpaca, vicuna, angora, spider silk, and the like. The fibers made of the optically active polypeptide (A2) preferably contain at least one of silk and spider silk from the viewpoint of piezoelectricity, and more preferably consist of at least one of silk and spider silk.

[0165] Examples of silk include raw silk, degummed silk, regenerated silk, fluorescent silk, and the like. As silk, raw silk or degummed silk is preferable, and refined silk is particularly preferable. Degummed silk means silk obtained by removing sericin from raw silk, which has a double structure of sericin and fibroin, and degumming means an operation of removing sericin from raw silk. The color of raw silk is dull white, but by removing sericin from raw silk (i.e., degumming), it changes from dull white to shiny silver-white. Also, degumming increases the soft texture.

[0166] The first long-shaped organic piezoelectric body 121 and the like preferably contain long fibers made of an optically active polypeptide (A2) from the viewpoint of piezoelectricity. This is presumably because the stress applied to the first piezoelectric sensor 10A is more likely to be transmitted to the first piezoelectric body 12A in the case of long fibers than in the case of short fibers. "Long fiber" means a fiber having a length that can be continuously wound from one end to the other end in the long direction of the first piezoelectric sensor 10A. Silk, wool, mohair, cashmere, camel, llama, alpaca, vicuna, angora, and spider silk all correspond to long fibers. Among the long fibers, silk and spider silk are preferable from the viewpoint of piezoelectricity.

[0167] When the first long organic piezoelectric body 121 contains the above fibers, the first long organic piezoelectric body 121 preferably contains at least one thread composed of at least one of the above fibers. As an aspect where the first long organic piezoelectric body 121 contains the above thread, there are an aspect where the first long organic piezoelectric body 121 is composed of one of the above threads, an aspect where the first long organic piezoelectric body 121 is an aggregate of a plurality of the above threads, and the like. The above thread may be a twisted thread or an untwisted thread, but from the viewpoint of piezoelectricity, it is preferably a thread having a twist number of 500 T / m or less (that is, a twisted thread or an untwisted thread (twist number 0 T / m) having a twist number of 500 T / m or less). Examples of the untwisted thread include one raw yarn, an aggregate of a plurality of raw yarns, and the like.

[0168] (First long organic piezoelectric body, and second long organic piezoelectric body) Next, the first long organic piezoelectric body 121 and the like will be further described.

[0169] <Stabilizer> The first long organic piezoelectric body 121 and the like preferably further contain a stabilizer (B) having a weight average molecular weight of 200 or more and 60,000 or less and having one or more functional groups selected from the group consisting of a carbodiimide group, an epoxy group, and an isocyanate group in one molecule. Thereby, the heat and humidity resistance can be further improved.

[0170] As the stabilizer (B), the "stabilizer (B)" described in paragraphs 0039 to 0055 of International Publication No. 2013 / 054918 can be used.

[0171] Examples of the compound containing a carbodiimide group in one molecule (carbodiimide compound) that can be used as the stabilizer (B) include a monocarboxylic diimide compound, a polycarboxylic diimide compound, and a cyclic carbodiimide compound. As the monocarboxylic diimide compound, dicyclohexylcarbodiimide, bis-2,6-diisopropylphenylcarbodiimide, and the like are suitable. In addition, as the polycarbodiimide compound, those produced by various methods can be used. Those produced by conventional polycarbodiimide production methods (for example, U.S. Patent No. 2,941,956, Japanese Patent Publication No. 47-33279, J. Org. Chem. 28, 2069-2075 (1963), Chemical Review 1981, Vol. 81 No. 4, p619-621) can be used. Specifically, the carbodiimide compound described in Japanese Patent No. 4,084,953 can also be used. Examples of the polycarbodiimide compound include poly(4,4'-dicyclohexylmethane carbodiimide), poly(N,N'-di-2,6-diisopropylphenylcarbodiimide), poly(1,3,5-triisopropylphenylene-2,4-carbodiimide), and the like. The cyclic carbodiimide compound can be synthesized based on the method described in Japanese Patent Application Laid-Open No. 2011-256337 and the like. As the carbodiimide compound, commercially available products may be used. For example, those manufactured by Tokyo Chemical Industry Co., Ltd., B2756 (trade name), those manufactured by Nisshinbo Chemicals, Inc., Carbodilite (registered trademark) LA-1 (trade name), those manufactured by Rhein Chemie, Stabaxol P, Stabaxol P400, Stabaxol I (all trade names), etc. can be mentioned.

[0172] Examples of the compound containing an isocyanate group in one molecule (isocyanate compound) that can be used as the stabilizer (B) include 3-(triethoxysilyl)propyl isocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, and the like.

[0173] Examples of the compound containing an epoxy group in one molecule (epoxy compound) that can be used as the stabilizer (B) include phenyl glycidyl ether, diethylene glycol diglycidyl ether, bisphenol A-diglycidyl ether, hydrogenated bisphenol A-diglycidyl ether, phenol novolak type epoxy resin, cresol novolak type epoxy resin, epoxidized polybutadiene, and the like.

[0174] As described above, the weight average molecular weight of the stabilizer (B) is 200 or more and 60,000 or less, more preferably 200 or more and 30,000 or less, and even more preferably 300 or more and 18,000 or less. If the molecular weight is within the above range, the stabilizer (B) is more likely to move, and the effect of improving the heat and humidity resistance is more effectively exhibited. It is particularly preferable that the weight average molecular weight of the stabilizer (B) is 200 or more and 900 or less. Note that a weight average molecular weight of 200 or more and 900 or less substantially coincides with a number average molecular weight of 200 or more and 900 or less. Further, when the weight average molecular weight is 200 or more and 900 or less, the molecular weight distribution may be 1.0. In this case, "weight average molecular weight of 200 or more and 900 or less" can be simply rewritten as "molecular weight of 200 or more and 900 or less".

[0175] When the first long organic piezoelectric body 121 or the like contains the stabilizer (B), the first long organic piezoelectric body 121 or the like may contain only one kind of stabilizer or two or more kinds of stabilizers. When the first long organic piezoelectric body 121 or the like contains the stabilizer (B), the content of the stabilizer (B) is preferably 0.01 part by mass or more and 10 parts by mass or less, more preferably 0.01 part by mass or more and 5 parts by mass or less, even more preferably 0.1 part by mass or more and 3 parts by mass or less, and particularly preferably 0.5 part by mass or more and 2 parts by mass or less with respect to 100 parts by mass of the helical chiral polymer (A1). When the content of the stabilizer (B) is 0.01 part by mass or more, the heat and humidity resistance is further improved. In addition, when the above content is 10 parts by mass or less, the decrease in transparency is more suppressed.

[0176] As a preferred embodiment of the stabilizer (B), there is a stabilizer (B1) having one or more functional groups selected from the group consisting of a carbodiimide group, an epoxy group, and an isocyanate group, and having a number average molecular weight of 200 or more and 900 or less, and a stabilizer (B2) having two or more functional groups selected from the group consisting of a carbodiimide group, an epoxy group, and an isocyanate group in one molecule and having a weight average molecular weight of 1000 or more and 60000 or less. The weight average molecular weight of the stabilizer (B1) having a number average molecular weight of 200 or more and 900 or less is generally 200 or more and 900 or less, and the number average molecular weight and the weight average molecular weight of the stabilizer (B1) are substantially the same value. When the stabilizer (B1) and the stabilizer (B2) are used in combination as the stabilizer, it is preferable to contain a large amount of the stabilizer (B1) from the viewpoint of improving transparency. Specifically, with respect to 100 parts by mass of the stabilizer (B1), it is preferable that the stabilizer (B2) is in the range of 10 parts by mass or more and 150 parts by mass or less from the viewpoint of achieving both transparency and heat and humidity resistance, and more preferably in the range of 50 parts by mass or more and 100 parts by mass or less.

[0177] Hereinafter, specific examples of the stabilizer (B) (stabilizers (B-1) to (B-3)) are shown.

[0178]

Chemical formula

[0179] Hereinafter, for the stabilizers (B-1) to (B-3), the compound names, commercially available products, etc. are shown. · Stabilizer (B-1)… The compound name is bis-2,6-diisopropylphenylcarbodiimide. The weight average molecular weight (equal to simply "molecular weight" in this example) is 363. Commercially available products include "Stabaxol I" manufactured by Rhein Chemie and "B2756" manufactured by Tokyo Chemical Industry. · Stabilizer (B-2)… The compound name is poly(4,4'-dicyclohexylmethane carbodiimide). As a commercially available product, one with a weight-average molecular weight of about 2000 is "Carbodilite (registered trademark) LA-1" manufactured by Nisshinbo Chemical Co., Ltd. · Stabilizer (B-3)… The compound name is poly(1,3,5-triisopropylphenylene-2,4-carbodiimide). As a commercially available product, one with a weight-average molecular weight of about 3000 is "Stabaxol P" manufactured by Rhein Chemie. Also, one with a weight-average molecular weight of 20000 is "Stabaxol P400" manufactured by Rhein Chemie.

[0180] <Other Components> The first long organic piezoelectric body 121 etc. may contain other components as required. Examples of other components include known resins such as polyvinylidene fluoride, polyethylene resin, and polystyrene resin; known inorganic fillers such as silica, hydroxyapatite, and montmorillonite; known crystal nucleating agents such as phthalocyanine; stabilizers other than stabilizer (B); etc. As the inorganic filler and crystal nucleating agent, the components described in paragraphs 0057 to 0058 of International Publication No. 2013 / 054918 can also be cited.

[0181] (Orientation Degree F) As described above, the orientation degree F of the first long organic piezoelectric body 121 etc. is 0.5 or more and less than 1.0, preferably 0.7 or more and less than 1.0, and more preferably 0.8 or more and less than 1.0. If the orientation degree F of the first long organic piezoelectric body 121 etc. is 0.5 or more, there are many molecular chains (for example, polylactic acid molecular chains) of the helical chiral polymer (A1) arranged in the stretching direction. As a result, the rate of formation of oriented crystals increases, and it becomes possible to exhibit higher piezoelectricity. If the orientation degree F of the first long organic piezoelectric body 121 etc. is less than 1.0, the longitudinal splitting strength is further improved.

[0182] (Crystallinity) The crystallinity of the first long, rod-shaped organic piezoelectric body 121 or the like is a value measured by the above-described X-ray diffraction measurement (wide-angle X-ray diffraction measurement). The crystallinity of the first long, rod-shaped organic piezoelectric body 121 or the like is preferably 20% or more and 80% or less, more preferably 25% or more and 70% or less, and still more preferably 30% or more and 60% or less. When the crystallinity is 20% or more, the piezoelectricity is maintained at a high level. When the crystallinity is 80% or less, the transparency of the first long, rod-shaped organic piezoelectric body 121 or the like is maintained at a high level. When the crystallinity is 80% or less, for example, when manufacturing an organic piezoelectric film as a raw material for the first long, rod-shaped organic piezoelectric body 121 or the like by stretching, whitening and breakage are less likely to occur, so it is easy to manufacture the first long, rod-shaped organic piezoelectric body 121 or the like. Further, when the crystallinity is 80% or less, for example, when manufacturing a raw material (e.g., polylactic acid) for the first long, rod-shaped organic piezoelectric body 121 or the like by stretching after melt spinning, the fiber has high flexibility and a flexible property, making it easy to manufacture the first long, rod-shaped organic piezoelectric body 121 or the like.

[0183] The biological information detection device 50 of the present embodiment is a device for acquiring biological information of a subject or a test animal (hereinafter, these are collectively referred to as "subject") by detecting a biological signal of the subject. Examples of the biological signal here include a pulse wave signal (heartbeat signal), a respiration signal, a body movement signal, a cardiac ejection, a body tremor, and the like. Body tremor refers to the rhythmic involuntary movement of a body part (such as a finger, hand, forearm, upper arm, etc.).

[0184] In addition, the detection of the above cardiac ejection includes the detection of the effect of the force due to the cardiac function of the body. That is, when the heart pumps blood into the aorta and pulmonary artery, the body receives a reaction force in the direction opposite to the blood flow. The magnitude and direction of this reaction force change with the functional stage of the heart. This reaction force is detected by sensing the cardiac ejection outside the body.

[0185] The biological information detection device 50 is disposed on various articles such as sofas, chairs, desks, tables, sheets, seats, toilets, massage chairs, beds, bed pads, carpets, baskets, masks, bandages, ropes, various nets, bathtubs, floor materials, wall materials, personal computers, mice, etc. and used. As articles on which the biological information detection device 50 is disposed, articles on which the weight of the subject is applied, such as footwear, insoles, sheets, zabutons, cushions, futons, futon covers, pillows, pillow covers, sofas, chairs, sheets, seats, toilets, beds, carpets, bathtubs, floor materials, etc., are preferable. More specifically, seats, seat parts, wheels of baby strollers for infants, stoppers for preventing infants from falling, etc.; seats, seat parts of wheelchairs, etc.; mats of medical incubators, etc. are preferable.

[0186] Hereinafter, an example of the operation of the biological information detection device 50 will be described. The biological information detection device 50 is disposed, for example, on a bed or on the seat surface of a chair. The subject lies down, sits, or stands up on this biological information detection device 50. In this state, when tension is applied to the biological information detection device 50 by a biological signal (body movement, periodic vibration (pulse, respiration, etc.), heart rate changed due to sensibilities such as "cute" or "scary" of humans, etc.) emitted from the subject, polarization occurs in the helical chiral polymer (A1) included in the piezoelectric sensor, and a potential proportional to the tension is generated. This potential changes with time along with the biological signal emitted from the subject. For example, when the biological signal emitted from the subject is a periodic vibration such as a pulse or respiration, the potential generated by the biological information detection device 50 also changes periodically. The time-dependent change in the potential generated with the application of tension to the biological information detection device 50 is acquired by the measurement module as a voltage signal. The time-dependent change in the acquired potential (voltage signal) is a composite wave of a plurality of biological signals (pulse wave signal (heartbeat signal), respiration signal, body movement signal). This composite wave is separated for each frequency by Fourier transform to generate a separated signal. By performing inverse Fourier transform on each of the generated separated signals, biological signals corresponding to each of the separated signals are obtained respectively.

[0187] For example, when the biological signal emitted from the subject is a composite wave of a heartbeat signal and a respiration signal, the potential generated with the application of tension to the biological information detection device 50 changes periodically over time. Generally, a person's pulse is 50 or more and 90 or less times per minute, and the period is 0.6 Hz or more and 3 Hz or less. Also, generally, a person's respiration is 16 or more and 18 or less times per minute, and the period is 0.1 Hz or more and 1 Hz or less. Also, generally, a person's body movement is 10 Hz or more. Based on these guidelines, a composite wave of a plurality of biological signals can be separated into each of the biological signals. Furthermore, a signal of a velocity pulse wave can also be obtained from the heartbeat signal. Separation of the composite wave of a plurality of biological signals into each of the biological signals is performed, for example, using a biological signal notification program and by the above Fourier transform and inverse Fourier transform.

[0188] As described above, a composite wave of a plurality of biological signals can be separated into each of the plurality of biological signals.

[0189] Furthermore, biological signal data may be generated based on at least one of the biological signals separated as described above. The biological signal data is not particularly limited as long as it is calculated based on the biological signal. Examples of the biological signal data include, for example, the number of biological signals per unit time, the average value of the number of past biological signals, and the like.

[0190] [Second Embodiment] In the first embodiment, a mode of detecting biological information using a differential signal obtained by differentially amplifying each voltage signal related to the first piezoelectric sensor 10A and the second piezoelectric sensor 10B has been described. In this embodiment, a mode of detecting biological information using the voltage signals related to the first piezoelectric sensor 10A and the second piezoelectric sensor 10B will be described.

[0191] Note that the schematic configuration diagram showing the support according to this embodiment (see FIG. 3), the cross-sectional view showing an example of the piezoelectric substrate (see FIG. 4), the graph showing the analysis result of FFT (see FIG. 6), and the front view showing the first piezoelectric sensor (see FIG. 7) are the same as those in the first embodiment, and thus the description thereof is omitted. Also, the cross-sectional view showing the cross-section of the first piezoelectric sensor (see FIG. 8) and the front view showing another aspect of the first piezoelectric sensor (see FIGS. 9 and 10) are the same as those in the first embodiment, and thus the description thereof is omitted.

[0192] Referring to FIG. 11, the biological information detection device 50 according to this embodiment will be described. FIG. 11 is a schematic configuration diagram of the biological information detection device 50 according to the embodiment of the present disclosure. Note that the same components as those of the biological information detection device 50 shown in FIG. 1 in FIG. 11 are denoted by the same reference numerals as those in FIG. 1, and the description thereof is omitted.

[0193] As shown in FIG. 11, the biological information detection device 50 includes a first piezoelectric sensor 10A, a second piezoelectric sensor 10B, a first coaxial cable 20A, a second coaxial cable 20B, and an information processing unit 40. The first piezoelectric sensor 10A is electrically connected to the information processing unit 40 via the first coaxial cable 20A. The second piezoelectric sensor 10B is electrically connected to the information processing unit 40 via the second coaxial cable 20B.

[0194] The first coaxial cable 20A includes a first conductor 21C, a first insulating layer 22A, and a first conductor layer 23C. The first conductor 21C electrically connects the first internal conductor 11A of the first piezoelectric sensor 10A and the information processing unit 40. The first insulating layer 22A covers the first conductor 21C. That is, the first conductor 21C and the first conductor layer 23C are not physically in contact. The first conductor layer 23C is electrically connected to the first external conductor 13A of the first piezoelectric sensor 10A. Also, the first conductor layer 23C is grounded. The first conductor layer 23C covers the first insulating layer 22A.

[0195] The second coaxial cable 20B has a second conductor 21D, a second insulating layer 22B, and a second conductor layer 23D. The second conductor 21D electrically connects the second internal conductor 11B of the second piezoelectric sensor 10B and the information processing unit 40. The second insulating layer 22B covers the second conductor 21D. That is, the second conductor 21D and the second conductor layer 23D are not physically connected. The second conductor layer 23D is electrically connected to the second external conductor 13B of the second piezoelectric sensor 10B. Also, the second conductor layer 23D is grounded. The second conductor layer 23D covers the second insulating layer 22B.

[0196] The information processing unit 40 converts the voltage signals output from the first piezoelectric sensor 10A and the second piezoelectric sensor 10B into digital signals and performs data processing. The data processing includes display of the voltage signals, detection of the external force F, recording of the voltage signals, etc. Details of the information processing unit 40 will be described later with reference to FIG. 12.

[0197] Referring to FIG. 12, the hardware configuration of the biological information detection device 50 according to the second embodiment will be described. FIG. 2 is a block diagram showing an example of the hardware configuration of the biological information detection device 50 according to the present embodiment.

[0198] As an example, as shown in FIG. 12, the biological information detection device 50 includes a first piezoelectric sensor 10A, a second piezoelectric sensor 10B, and an information processing unit 40. The first piezoelectric sensor 10A, the second piezoelectric sensor 10B, and the information processing unit 40 are electrically connected.

[0199] The information processing unit 40 includes a processing PC 41 and an AD converter 42. The processing PC 41 includes a CPU 41A, a ROM 41B, a RAM 41C, a storage 41D, a communication I / F 41E, a monitor 41F, and an input / output I / F 41G. The CPU 41A, the ROM 41B, the RAM 41C, the storage 41D, the communication I / F 41E, the monitor 41F, and the input / output I / F 41G are communicably connected to each other via a bus 41H.

[0200] The CPU 41A is a central processing unit that executes various programs and controls each part. That is, the CPU 41A reads a program from the ROM 41B or the storage 41D and executes the program using the RAM 41C as a work area. In the present embodiment, an execution program for executing various processes is stored in the storage 41D. By executing the execution program, the CPU 41A functions as a detection unit 71B, a conversion unit 72B, a specification unit 73B, a detection unit 74B, and an output unit 75B shown in FIG. 13.

[0201] The AD converter 42 converts a voltage signal, which is an analog signal output from the first piezoelectric sensor 10A and the second piezoelectric sensor 10B, into a digital signal.

[0202] (Operation of the biological information detection device) FIG. 13 is a block diagram showing an example of the functional configuration of the biological information detection device 50. As shown in FIG. 13, the biological information detection device 50 includes a detection unit 71B, a conversion unit 72B, a specification unit 73B, a detection unit 74B, and an output unit 75B. Each functional configuration is realized by the CPU 41A reading and executing an execution program stored in the storage 41D.

[0203] The detection unit 71B detects voltage signals in the first piezoelectric sensor 10A and the second piezoelectric sensor 10B via the input / output I / F 41G.

[0204] The conversion unit 72B uses fast Fourier transform (FFT) to convert the voltage signals related to the first piezoelectric sensor 10A and the second piezoelectric sensor 10B detected by the detection unit 71B from voltage signals for each time to voltage signals for each frequency.

[0205] The specific part 73B identifies the biological information using the analysis result of the FFT converted by the conversion part 72B. Specifically, the specific part 73B identifies the peak value of the analysis value in the analysis result of the FFT to identify the biological information. For example, when the ratio of the peak value of the analysis value related to the first piezoelectric sensor 10A and the peak value of the analysis value of the second piezoelectric sensor 10B corresponding to the peak value is 0.5 or less, the voltage signal of the frequency is identified as biological information. Specifically, when the ratio of the peak value of the analysis value of the second piezoelectric sensor 10B corresponding to the peak value to the peak value of the analysis value related to the first piezoelectric sensor 10A is 0.5 or less, the voltage signal of the frequency is identified as biological information.

[0206] As an example, FIG. 14 shows the analysis value 81 of the voltage signal related to the first piezoelectric sensor 10A and the analysis value 82 of the voltage signal related to the second piezoelectric sensor 10B as the analysis result of the FFT. The specific part 73B identifies, for example, the peak value of the analysis value 81 shown in the range of 1 Hz to 1.2 Hz using the analysis result of the FFT shown in FIG. 14. When the ratio of the peak value of the analysis value 82 corresponding to the peak value and the peak value of the analysis value 81 is 0.5 or less, the voltage signal of the frequency related to the peak value is identified as biological information indicating the heartbeat. Specifically, when the ratio of the peak value of the analysis value 82 to the peak value of the analysis value 81 is 0.5 or less, the voltage signal of the frequency is identified as biological information.

[0207] The detection part 74B detects the voltage signal related to the identified frequency from the voltage signal for each time as biological information.

[0208] The output part 75B outputs the biological information detected by the detection part 74B to the monitor 41F. Note that the detected biological information may be output to an external device via the communication I / F 41E or stored in the storage 41D.

[0209] In the present embodiment, a form of specifying biological information using the analysis result of FFT has been described. However, the present invention is not limited to this. Biological information may be specified using the voltage signals for each time detected by the first piezoelectric sensor 10A and the second piezoelectric sensor 10B. For example, the first piezoelectric sensor 10A detects biological information and vibrations caused by the seat cushion 61, and the second piezoelectric sensor 10B detects vibrations caused by the seat cushion 61. Therefore, the difference between the voltage signal for each time in the first piezoelectric sensor 10A and the voltage signal for each time in the second piezoelectric sensor 10B indicates biological information. That is, the specifying unit 73B may specify biological information by deriving the difference between the voltage signal for each time in the first piezoelectric sensor 10A and the voltage signal for each time in the second piezoelectric sensor 10B.

[0210] As described above, even when using the voltage signals related to the first piezoelectric sensor 10A and the second piezoelectric sensor 10B, the same operational effects as those of the first embodiment can be achieved. That is, in a situation where vibrations from the outside other than the human body can be detected, biological information can be accurately detected.

[0211] [Remarks] In the above-described embodiments, in the first embodiment, a form of detecting biological information using the differential signal detected from the instrumentation amplifier 30 has been described. In the second embodiment, a form of detecting biological information using the voltage signals detected from the first piezoelectric sensor 10A and the second piezoelectric sensor 10B has been described. However, the present invention is not limited to this. The first embodiment and the second embodiment may be combined. That is, voltage signals and differential signals may be detected from the first piezoelectric sensor 10A, the second piezoelectric sensor 10B, and the instrumentation amplifier 30, respectively. For example, using the analysis result of FFT in the voltage signal of the differential voltage, the peak value of the analysis value is specified, and the ratio of the analysis value 81 related to the first piezoelectric sensor 10A corresponding to the peak value to the analysis value 82 related to the second piezoelectric sensor 10B (the analysis value 82 with respect to the analysis value 81) is derived. When the derived ratio is 0.5 or less, the voltage signal of the frequency may be specified as biological information.

Example

[0212] [Example 1] (Fabrication of the First and Second Piezoelectric Sensors) 10 parts by mass of the following stabilizer A, 70 parts by mass of the following stabilizer B, and 20 parts by mass of the following stabilizer C were mixed to obtain stabilizer D. Next, 1.0 part by mass of stabilizer D was added to 100 parts by mass of the following polylactic acid and dry-blended to prepare a raw material.

[0213] The following products were used for the polylactic acid, stabilizer A, stabilizer B, and stabilizer C. Polylactic acid: “IngeoTM biopolymer 4032D” (manufactured by NatureWorks LLC, helical chiral polymer (A)) Stabilizer A: “Stabaxol P400” (manufactured by Rhein Chemie, weight-average molecular weight: 20,000) Stabilizer B: “Stabaxol I” (manufactured by Rhein Chemie, weight-average molecular weight: 363) Stabilizer C: “Carbodilite (registered trademark) LA-1” (manufactured by Nisshinbo Chemical Inc., weight-average molecular weight: 2,000)

[0214] The prepared raw material was put into the hopper of an extrusion molding machine, extruded from a T-die while heating to 210°C, and brought into contact with a casting roll at 50°C for 0.3 minutes to form a pre-crystallized sheet with a thickness of 150 μm (pre-crystallization step). The obtained pre-crystallized sheet was heated to 70°C and stretched in the machine direction (MD) at a stretching speed of 10 m / min in a roll-to-roll manner to start stretching and uniaxially stretched 3.5 times in the MD direction (stretching step).

[0215] Thereafter, the uniaxially stretched film was brought into contact with a roll heated to 145°C for 15 seconds in a roll-to-roll manner for annealing treatment and then rapidly cooled to fabricate an organic piezoelectric film (annealing treatment step).

[0216] Next, using a slitting machine, the organic piezoelectric film was slit so that the slitting direction of the organic piezoelectric film was substantially parallel to the stretching direction of the organic piezoelectric film, to obtain a slit ribbon (first long organic piezoelectric body 121) of the organic piezoelectric film with a width of 0.6 mm and an average thickness of 50 μm.

[0217] A left-wound first piezoelectric sensor 10A made of the slit ribbon of the organic piezoelectric film and a left-wound second piezoelectric sensor 10B made of the slit ribbon of the organic piezoelectric film were prepared as follows.

[0218] As the first internal conductor 11A and the second internal conductor 11B, silk threads with a radius of 0.135 mm and a length of 100 mm were prepared. The silk threads used were those in which copper foil was wound around a polyester thread in a right-handed manner. The obtained slit ribbon of the organic piezoelectric film was wound spirally to the left at an angle of 45° (helix angle) with respect to the long axis direction of the silk thread without any gaps so that the silk thread was not visible (not exposed), thereby encapsulating the silk thread. As a result, a coaxial line structure composed of the silk thread and the slit ribbon (first piezoelectric body 12A and second piezoelectric body 12B) was obtained. The number of turns of the slit ribbon around the silk thread at this time was 17 turns / cm.

[0219] Next, as the first external conductor 13A and the second external conductor 13B, copper foil ribbons slit to a width of 0.6 mm and a thickness of 100 mm were prepared. This copper foil ribbon was wound and encapsulated around the slit ribbon of the coaxial line structure in the same manner as the slit ribbon of the above-described organic piezoelectric film without any gaps so that the slit ribbon of the organic piezoelectric film was not visible. In this way, the first piezoelectric sensor 10A and the second piezoelectric sensor 10B were obtained. The average radius of the silk thread and the average thickness of the slit ribbon of the first piezoelectric sensor 10A and the second piezoelectric sensor 10B were measured by the method described above. The average radius of the silk thread of the first piezoelectric sensor 10A and the second piezoelectric sensor 10B was 0.135 mm, and the average thickness of the slit ribbon was 0.05 mm.

[0220] <Fabrication of Sensor Mat> The first piezoelectric sensor 10A and the second piezoelectric sensor 10B cut to a length of 400 mm were prepared, and the first piezoelectric sensor 10A and the second piezoelectric sensor 10B were electrically connected to the 2 m first coaxial cable 20A and the second coaxial cable 20B (3C2V) with jack connectors, respectively.

[0221] Specifically, when connecting the first piezoelectric sensor 10A to the female connector, the rear end of the first internal conductor 11A of the first piezoelectric sensor 10A and the center-side terminal of the female connector were soldered, and the rear end of the first external conductor 13A of the first piezoelectric sensor 10A and the outer terminal of the female connector were soldered, and a metal cover was screwed on and attached.

[0222] In the first coaxial cable 20A, the first conductor 21A and the male connector terminal corresponding to the female connector terminal to which the first internal conductor 11A was connected were soldered and connected. In the first coaxial cable 20A, the first conductor layer 23A and the male connector terminal corresponding to the female connector terminal to which the first external conductor 13A was connected were soldered and prepared, and the connector was inserted and connected. Also, at the connection part of the connector, taking care not to short-circuit, it was wound with a copper foil as a shield and soldered and fixed to the terminal side connected to the external copper foil. The second piezoelectric sensor 10B was also connected to the connector in the same manner as the first piezoelectric sensor 10A.

[0223] Next, the first piezoelectric sensor 10A was attached to the upper side of the cushion with Kapton tape. Here, a Nitto low-rebound sheet cushion "Bresa" was used for the cushion. Specifically, as shown in FIG. 15, the cover outside the cushion was removed, and when a person sits, the first piezoelectric sensor 10A was installed so as to be parallel to the width direction at the position where the thigh comes (the upper part of the cushion and about 4 cm from the front end in the depth direction), and attached with Kapton tape so as not to shift. Also, the second piezoelectric sensor 10B was attached and fixed to the lower part of the cushion with Kapton tape so as not to shift and be substantially parallel to the first piezoelectric sensor. In the first piezoelectric sensor 10A and the second piezoelectric sensor 10B fixed to the cushion, the side to which the first coaxial cable 20A and the second coaxial cable 20B were not connected was covered with the cushion cover again. The first coaxial cable 20A and the second coaxial cable 20B were taken out from the position where the zipper in the cushion cover was opened, and the female connectors of the first coaxial cable 20A and the second coaxial cable 20B were electrically connected to the instrumentation amplifier 30 housed in the metal housing. "INA128" (manufactured by TI) was used for the instrumentation amplifier 30.

[0224] The first differential input terminal V of the instrumentation amplifier 30 IN - was connected to the first conductor 21A of the first coaxial cable 20A related to the first piezoelectric sensor 10A installed on the upper part of the cushion. The second differential input terminal V of the instrumentation amplifier 30 IN + was connected to the second conductor 21B of the second coaxial cable 20B related to the second piezoelectric sensor 10B installed on the lower part of the cushion. After passing this output through a buffer amplifier, the magnification was set to 10 times with an operational amplifier for gain adjustment (manufactured by TI, LM358AD), and the reference terminal V of the instrumentation amplifier 30 ref was connected to the first conductor layer 23A of the first coaxial cable 20A, the second conductor layer 23B of the second coaxial cable 20B, and the metal housing that houses the instrumentation amplifier 30.

[0225] That is, the first internal conductor 11A of the first piezoelectric sensor 10A was connected to the first differential input terminal V of the instrumentation amplifier 30 IN- is electrically connected. The internal conductor 11B of the second piezoelectric sensor 10B is connected to the second differential input terminal V of the instrumentation amplifier 30 IN + is electrically connected. The first external conductor 13A of the first piezoelectric sensor 10A and the second external conductor 13B of the second piezoelectric sensor 10B are connected to the reference terminal V of the instrumentation amplifier 30 ref is electrically connected.

[0226] Next, this cushion is set on the chair, the output terminal V of the instrumentation amplifier 30 OUT is connected to a voltmeter, and a person as a subject sits on it. During the measurement, weak irregular vibrations were transmitted to the chair. The voltage signal of the sensor was measured in this state. Using the "USB-6002" manufactured by National Instrument, voltage measurement was performed, data was captured into a PC (Personal Computer), and using the software of LabView, the time change of the voltage was captured into the personal computer and displayed. As shown in FIG. 16, the peak waveform of the voltage at a timing close to a 1-second cycle was read, and the biological information derived from the heartbeat was obtained.

[0227] Here, the output related to the first piezoelectric sensor 10A is input to Ch2 and the output related to the second piezoelectric sensor 10B is input to Ch3 at the input terminal of the USB-6002, and the respective voltage signals are subjected to FFT analysis to evaluate the frequency characteristics. The FFT analysis was performed using the spectrum measurement configuration ExpressVI of LabView under the conditions of amplitude measurement, Hanning window, number of samples: 32768, and rate 1 kHz. In the peak waveform of the FFT analysis obtained from the first piezoelectric sensor 10A arranged near the subject, the frequency of the maximum peak value with a high detection level near 1 Hz derived from the heartbeat was 1.19 Hz, and the peak value was 41.7 mV. The peak value of the second piezoelectric sensor 10B at this frequency was 16.6 mV. The intensity ratio derived using each peak value was 0.40.

[0228] In the voltage signals of the first piezoelectric sensor 10A and the second piezoelectric sensor 10B to be measured, depending on the signal levels other than the biological signal, by differentially detecting while changing the amplification factors respectively, the biological signal is clearly detected.

[0229] [Comparative Example 1] In the same setting as in Example 1, in order to detect the biological signal of the first piezoelectric sensor 10A, after adjusting the amplification factor to 10 times, the output of the voltage signal was measured, and the measurement results shown in Fig. 17(a) were obtained. Since the obtained measurement results are considered to contain signals different from the biological signal such as vibrations from the chair in addition to the biological signal, the biological information is unclear.

[0230] [Comparative Example 2] In the same setting as in Example 1, in order to detect the signal of the second piezoelectric sensor 10B, after adjusting the magnification to 10 times, the output of the signal was taken out, and the detection signal data shown in Fig. 17(b) were obtained. Since the obtained detection signal data are considered to mainly detect signals different from the biological signal such as vibrations from the chair, the biological signal is unclear.

[0231] The measurement results in Example 1 described above are the results of measuring the differential signal between the first piezoelectric sensor 10A that detects the biological signal and a signal different from the biological signal, and the second piezoelectric sensor 10B that detects a signal different from the biological signal, at the same timing. That is, the measurement results of Example 1 show that the biological signal becomes clear and the biological information is detected by canceling the signal different from the biological signal in the first piezoelectric sensor 10A with the signal different from the biological signal in the second piezoelectric sensor 10B.

[0232] Regarding one embodiment of the technology disclosed in the present application described above, the following additional remarks are further disclosed.

[0233] (Additional Remark 1) The piezoelectric body has piezoelectric constants d 33 and piezoelectric constant d 31 and has piezoelectric constant d 14The sheet-like piezoelectric body containing a piezoelectric material having no The biological information detection device according to <8>.

[0234] (Appendix 2) The sheet-like piezoelectric body contains polyvinylidene fluoride The biological information detection device according to Appendix 1.

Explanation of symbols

[0235] 10A First piezoelectric sensor 10B Second piezoelectric sensor 11A First internal conductor 11B Second internal conductor 12A First piezoelectric body 12B Second piezoelectric body 121 First long organic piezoelectric body 13A First external conductor 13B Second external conductor 30 Instrumentation amplifier 50 Biological information detection device V IN- First differential input terminal V IN+ Second differential input terminal V ref Reference terminal

Claims

1. A first piezoelectric substrate provided on a support installed at a predetermined location and detecting pressure received from a human body supported by the support; A second piezoelectric substrate provided on the support and detecting vibration of the support; A processor; and The processor detects biological information based on output signals detected from each of the piezoelectric substrates. The processor identifies, as the biological information, data of a frequency at which a ratio of a first peak value in an analysis value of an FFT of an output signal detected from the first piezoelectric substrate to a second peak value at the same frequency as the frequency of the first peak value in the analysis value of the FFT of the output signal detected from the second piezoelectric substrate satisfies a predetermined condition. A biological information detection device.

2. The support is fixed to a moving body as the predetermined location. The second piezoelectric substrate detects vibration of the support caused by the moving body. The biological information detection device according to Claim 1.

3. The first piezoelectric substrate and the second piezoelectric substrate are of the same type of piezoelectric substrate. The processor detects a biological signal based on a differential signal between an output signal detected from the first piezoelectric substrate and an output signal detected from the second piezoelectric substrate. The biological information detection device according to Claim 1 or Claim 2.

4. The predetermined condition is a case where a ratio of the second peak value to the first peak value is 0.5 or less. The biological information detection device according to any one of Claims 1 to 3.

5. The first piezoelectric substrate is provided along a pressure-receiving surface that receives pressure from the human body on the support. The biological information detection device according to any one of Claims 1 to 4.

6. The second piezoelectric substrate is provided along the pressure-receiving surface on the support and is installed at a location farther from the human body than the first piezoelectric substrate. The biological information detection device according to Claim 5.

7. The piezoelectric substrate includes a long conductor and a long piezoelectric body spirally wound around the conductor in one direction. The biological information detection device according to any one of Claims 1 to 6.

8. The piezoelectric body is a long organic piezoelectric body including an organic piezoelectric material having a piezoelectric constant d14. The biological information detection device according to Claim 7.

9. The organic piezoelectric material includes an optically active polypeptide fiber indicating a fiber made of an optically active polypeptide. The biological information detection device according to Claim 8.

10. The piezoelectric body is a helical chiral polymer (A) having optical activity The biological information detection device according to any one of claims 7 to 9. **Claim 11** The helical chiral polymer (A) is polylactic acid The biological information detection device according to claim 10.

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