Biological information detection device

Abstract

This biological information detection device comprises: a linear first sensor provided to a support installed at a prescribed location, the first sensor sensing pressure that is applied in a radial direction and is received from a living body supported by the support; and a second sensor for sensing pressure received from the living body supported by the support.

Description

Biometric information detection device

[0001] The disclosed technology relates to a biological information detection device.

[0002] Conventionally, in order to determine whether a human body on a bed device has left the bed, a device has been disclosed in which a computer is capable of acquiring vibration data from a first sensor and a second sensor installed on the bed device, and if the vibration data acquired from the first sensor is substantially identical to the vibration data acquired from the second sensor, the computer determines that the human body has left the bed (see JP 2023-111447 A).

[0003] However, the device described in JP 2023-111447 A requires processes such as calculating differential data between the detection results of the first sensor and the second sensor and comparing the differential data with a threshold value, which may delay the determination of whether the person has left the bed.

[0004] In view of the above circumstances, the disclosed technique aims to provide a biological information detection device that can reliably and quickly determine whether a person has gotten out of bed or sat up.

[0005] The means for solving the above problems include the following embodiments.

[0006] <1> A biological information detection device having: a linear first sensor provided on a support installed at a predetermined location and detecting pressure applied in a radial direction from a living body supported on the support; and a second sensor detecting pressure from the living body supported on the support.

[0007] <2> The biological information detection device according to <1>, wherein the first sensor is a sensor capable of acquiring biological information based on pressure.

[0008] <3> The biological information detection device according to <1>, wherein the second sensor is a resistive pressure sensor.

[0009] <4> The biological information detection device described in <1>, wherein the support is a bed on which the living body lies, and the first sensor and the second sensor are arranged at least in an upper body region when the living body lies on the bed.

[0010] <5> The biological information detection device according to <1>, wherein the support is a bed on which the living body lies, and the first sensor and the second sensor are arranged along a width direction of the bed.

[0011] <6> The biological information detection device according to <1>, wherein the first sensor and the second sensor are arranged parallel to each other.

[0012] <7> The biological information detection device described in <1>, wherein the first sensor and the second sensor are arranged on the support along a pressure-receiving surface that receives pressure from the living body, and the second sensor is installed at a location farther from the living body than the first sensor.

[0013] <8> The biological information detection device according to <1>, wherein the first sensor includes: an elongated conductor; and an elongated piezoelectric body wound spirally in one direction around the conductor.

[0014] <9> The first sensor has a piezoelectric constant d １４ The biological information detecting device according to <8>, wherein the organic piezoelectric body is a long organic piezoelectric body including an organic piezoelectric material having the formula:

[0015] <10> The biological information detection device according to <8> or <9>, wherein the first sensor is an optically active helical chiral polymer (A).

[0016] <11> The biological information detection device according to <10>, wherein the helical chiral polymer (A) is polylactic acid.

[0017] According to the present disclosure, a biological information detection device is provided that can reliably and quickly determine whether a person has gotten out of bed or is sitting up.

[0018] FIG. 1 is an exploded perspective view of a bed apparatus according to an embodiment. FIG. 2 is a cross-sectional view (cross-sectional view along line A-A in FIG. 1) of a sensor unit of a biological information detection device according to an embodiment. FIG. 3 is a block diagram showing an example of a hardware configuration of a biological information detection device according to an embodiment. FIG. 4 is a block diagram showing an example of a functional configuration of a biological information detection device according to an embodiment. FIG. 5 is a front view showing one mode of a first pressure sensor according to an embodiment. FIG. 6 is a cross-sectional view along line V1-V1 in FIG. 5 according to an embodiment. FIG. 7 is a diagram showing an example of detection results of the first pressure sensor and the second pressure sensor when using a biological information detection device according to an embodiment. FIG. 8 is a diagram showing another example of detection results of the first pressure sensor and the second pressure sensor when using a biological information detection device according to an embodiment.

[0019] Hereinafter, a bed apparatus 100, which is a human body detection system according to the present disclosure, and a biological information detection device 50 included in the bed apparatus 100 will be described with reference to the drawings. Note that the same reference numerals are used to designate the same or equivalent components and parts in each drawing. Also, the dimensional proportions in the drawings are exaggerated for the sake of explanation and may differ from the actual proportions.

[0020] [Biometric Information Detection Device] As shown in Fig. 1, the bed device 100 of this embodiment includes a bed 200 with legs and a biological information detection device 50. The bed 200 includes a frame 210 placed on the floor, a floorboard 220 covering the center of the frame 210, and a mattress 230 placed on the floorboard 220. The mattress 230, which serves as a pressure applying unit, is a plate-shaped urethane foam covered with polyester fabric. The mattress 230 is placed on the floorboard 220 and a sensor unit 32 (described later), and a human body lies on the upper surface of the mattress 230. The bed 200 of this embodiment is an example of a support, and the sensor unit 32 is pressed by the human body lying on the mattress 230 via the mattress 230.

[0021] In this embodiment, the portion of the mattress 230 that receives pressure is made of polyurethane (urethane foam), but it is not limited to this and may also be made of fiber or latex. Furthermore, the pressure-applying portion does not necessarily have to be the mattress 230 provided in the bed 200, but may also be a sheet, a mat, or a futon mattress. The thickness of the mattress 230 is in the range of 0.005 to 50 mm, and the hardness of the mattress 230, when measured in accordance with Method A specified in JIS K6400-2, is in the range of 50 to 200 N, preferably 100 to 200 N, and more preferably 110 to 170 N.

[0022] In accordance with Method A of JIS K6400-2, the hardness of the mattress 230 of this embodiment is determined as follows. That is, the hardness of the mattress 230 is determined by placing the foam filling of the mattress 230 flat, placing a circular pressure plate with a diameter of 200 mm on it, and compressing the foam to a distance of 75% of its original thickness, then returning it to its original position and compressing it again to a distance of 40% of its original thickness, and allowing it to remain stationary for 30 seconds. The bed apparatus 100 of this embodiment functions as a bed 200 with the frame 210, floorboard 220, and mattress 230. However, by installing a sensor unit 32 between the floorboard 220 and the mattress 230, it is possible to detect a human body on the floor surface. Note that the sensor unit 32 is not limited to being installed between the floorboard 220 and the mattress 230; the sensor unit 32 may also be installed on the top surface of the mattress 230.

[0023] As shown in FIG. 1 , the biological information detection device 50 includes a sensor unit 32 and an information processing unit 40. The sensor unit 32 is disposed in an upper body region 200A when a human body lies on the bed 200. The sensor unit 32 is also installed between the mattress 230 and the floorboard 220 of the bed 200, along a pressure-receiving surface that receives pressure from the human body lying on the bed 200. When the human body lies on the upper surface of the mattress 230, the sensor unit 32 detects the pressure (see arrow P) received from the human body. As shown in FIG. 1 , the sensor unit 32 is disposed along the width direction of the bed 200. That is, the sensor unit 32 is installed in a direction crossing the lying human body.

[0024] The sensor unit 32 is configured so that the first pressure sensor and the second pressure sensor can detect pressure (see arrow P) applied from a direction intersecting the reference plane 33, with the mounting surface on a support plate 36 (described later) being a reference plane 33 (see FIG. 2). As shown in FIG. 2, the sensor unit 32 includes a support plate 36 placed on the floor board 220, an insulating member 38 bonded to the support plate 36, a second pressure sensor 20 on a sheet mounted on the upper surface of the insulating member 38, the insulating member 38 mounted on the upper surface of the second pressure sensor 20, a first buffer material 37A mounted on the upper surface of the insulating member, a second buffer material 37B mounted on the upper surface of the first buffer material 37A, the insulating member 38 mounted on the upper surface of the second buffer material 37B, a cable-shaped first pressure sensor 10 mounted on the upper surface of the insulating member 38, and the insulating member 38 mounted on the upper surface of the first pressure sensor 10. That is, the second pressure sensor 20 is placed at a location farther from the body of a person lying on the bed 200 than the first pressure sensor 10. Furthermore, each member is adhered with double-sided tape 34. Note that in this embodiment, the first pressure sensor 10 is covered by adhering insulating members 38 to which double-sided tape 34 has already been attached, but this is not limited to this. For example, opposing insulating members 38 may be adhered together using an adhesive so that the first pressure sensor 10 is sandwiched between them.

[0025] The support plate 36 serving as a holding plate is a plate-like member that supports the buffer material 37 and is made of, for example, aluminum. As an example, the dimensions of the support plate 36 can be set to a length of 650 mm and a width of 20 mm.

[0026] The first and second buffer materials 37A and 37B as buffers are sponge sheets provided to relieve pressure applied to the second pressure sensor. The first and second buffer materials 37A and 37B in this embodiment are made of the same material and have a density of 0.05 to 0.5 kg / m ３ and has an Asker C hardness in the range of 5 to 60 as specified in JIS K7312. Specific materials suitable for use as the first buffer material 37A and the second buffer material 37B include foamed rubber and foamed resin materials. Examples of foamed resin materials that can be used include soft polyurethane foam, hard polyurethane foam, polystyrene foam, polyethylene foam, polypropylene foam, EVA crosslinked foam, PET resin foam, phenol foam, silicone foam, polyvinyl chloride foam, urea foam, acrylic foam, polyimide foam, and EPDM foam.

[0027] The first buffer material 37A has dimensions of 630 mm in length, 20 mm in width, and 5 mm in thickness, while the second buffer material 37B has dimensions of 630 mm in length, 5 mm in width, and 5 mm in thickness. That is, the width of the second buffer material 37B is set narrower than that of the first buffer material. In other words, the buffer material 37 is formed so that the width on the first pressure sensor 10 side is narrower than the width on the support plate 36 (reference surface 33) side. Note that the thicknesses of the first buffer material 37A and the second buffer material 37B do not necessarily have to be the same.

[0028] The first pressure sensor 10 is a linear sensor that detects pressure applied radially by a human body lying on the mattress 230, and generates a voltage when subjected to pressure. The first pressure sensor 10 is electrically connected to the information processing unit 40 via a coaxial cable 110 serving as wiring. The detailed structure of the first pressure sensor 10 will be described later. By incorporating the structure described later, the first pressure sensor 10 functions as a sensor that can acquire biological information from pressure. Here, the biological information includes heart rate, respiratory rate, amount of body movement, blood pressure, amount of sweat, brain waves, body temperature, stress level, voice volume, and the like. Furthermore, by incorporating the structure described later, the first pressure sensor 10 is characterized by faster pressure detection than the second pressure sensor 20. Here, the first pressure sensor 10 is an example of a "first sensor."

[0029] The second pressure sensor 20 is a sheet-like sensor that detects pressure exerted by a human body lying on the mattress 230. The second pressure sensor 20 may be any pressure sensor that detects pressure exerted by a human body, and the pressure to be detected may be air pressure or resistive pressure. Specifically, the second pressure sensor 20 is a so-called resistive pressure sensor in which the resistance value changes when pressure is applied to the second pressure sensor 20, and the output voltage changes in accordance with the change in resistance value. For example, the SF15-600 manufactured by LEANSTAR or the FSR (Force Sensing Resistor)-408 manufactured by Interlink Electronics, Inc. are preferably used. The second pressure sensor 20 is a sensor capable of detecting steady pressure. The second pressure sensor 20 is electrically connected to the information processing unit 40 via a coaxial cable 110 as wiring. Here, the second pressure sensor 20 is an example of a "second sensor."

[0030] In this embodiment, the first pressure sensor 10 and the second pressure sensor 20 each extend in the direction D1. That is, the first pressure sensor 10 and the second pressure sensor 20 are arranged parallel to each other. Here, "parallel" includes a state in which the first pressure sensor 10 and the second pressure sensor 20 are in a relationship that can be seen as parallel at a glance. Specifically, "approximately parallel" means that the angle between the first pressure sensor 10 and the second pressure sensor 20 is less than 10 degrees.

[0031] Examples of the insulating member 38 include commercially available adhesive tape, flexible insulating film, adhesive film, etc. As the insulating member 38 in this embodiment, for example, a biaxially oriented nylon film, polyimide film, polyethylene terephthalate film, polyphenylene sulfide film, polysulfene sulfide film, polyester film, polystyrene film, etc., having a Young's modulus of 2.0 to 10 GPa and a thickness of 4 to 50 μm, can be used.

[0032] As described above, in the sensor unit 32 of this embodiment, the mattress 230, the insulating member 38, the first pressure sensor 10, the insulating member 38, the buffer material 37, the insulating member 38, the second pressure sensor 20, the insulating member 38, and the support plate 36 are arranged in this order along the direction of pressure applied by the body of the person in bed (i.e., the direction of arrow P). The first pressure sensor 10 is installed closer to the body of the person lying on the bed 200 than the second pressure sensor 20 because the first pressure sensor 10 functions as a sensor that can acquire biological information using pressure, and therefore the closer the first pressure sensor 10 is to the human body, the more accurately it can acquire the biological information.

[0033] The information processing unit 40 detects the output signal from the sensor unit 32. As shown in Fig. 3, the information processing unit 40 includes an AD converter 42 that converts the analog voltage signal output from the first pressure sensor 10 through the amplifier circuit 43 and the analog voltage signal output from the second pressure sensor 20 through the voltage conversion circuit 44 and the amplifier circuit 43 into digital signals, and a processing PC 50 that detects the converted digital signals of the first pressure sensor 10 and the second pressure sensor 20. The AD converter 42 has a plurality of input terminals for inputting analog signals, and the first pressure sensor 10 and the second pressure sensor 20 are electrically connected to each input terminal. Note that a filter circuit may be provided between the first pressure sensor 10 and the AD converter 42, particularly between the amplifier circuit 43 and the AD converter 42, as needed. 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 (Interface) 41E, a monitor 41F, and an input / output I / F 40G. The CPU 41A, ROM 41B, RAM 41C, storage 41D, communication I / F 41E, monitor 41F, and input / output I / F 40G are connected to each other via a bus 41H so as to be able to communicate with each other. The processing PC 41 may include a personal computer as well as a computer such as a smartphone.

[0034] The CPU 41A is a central processing unit that executes various programs and controls each component. That is, the CPU 41A reads programs from the ROM 41B or the storage 41D and executes the programs using the RAM 41C as a work area. In this embodiment, the storage 41D stores execution programs for executing various processes. By executing the execution programs, the CPU 41A functions as the detection unit 55, determination unit 56, and notification unit 57 shown in FIG. 4. The ROM 41B stores various programs and various data. The RAM 41C temporarily stores programs or data as a work area. The storage 41D, which serves as a storage unit, is configured with an HDD (Hard Disk Drive) or an SSD (Solid State Drive) and stores various programs, including an operating system, and various data.

[0035] The communication I / F 41E is an interface for communicating with a mobile terminal such as a smartphone, and uses standards such as Ethernet (registered trademark), FDDI, Wi-Fi (registered trademark), and Bluetooth (registered trademark). The input / output I / F 40G is an interface for communicating with each device that constitutes the information processing unit 40. An AD converter 42 is connected to the processing PC 41 of this embodiment via the input / output I / F 40G.

[0036] Fig. 4 is a block diagram showing an example of the functional configuration of the CPU 41A. As shown in Fig. 4, the CPU 41A has a detection unit 55, a determination unit 56, and a notification unit 57. Each functional configuration is realized by the CPU 41A reading and executing an execution program stored in the storage 41D.

[0037] The detection unit 55 has a function of detecting the digital signals related to the first pressure sensor 10 and the second pressure sensor 20 output from the AD converter 42 via the communication I / F 41E.

[0038] The determination unit 56 has a function of determining whether the human body is lying in bed 200 or sitting up, based on the detection results of the first pressure sensor 10 and the second pressure sensor 20 detected by the detection unit 55. For example, when the voltage output of the first pressure sensor 10 fluctuates beyond a predetermined threshold, the determination unit 56 determines whether the human body has transitioned from a lying state to a sitting up state, or from a sitting up state to a lying down state. In addition, in this embodiment, the determination unit 56 determines that the human body has transitioned from a sitting up state to a lying down state when the voltage output of the second pressure sensor 20 decreases beyond a predetermined threshold. In addition, the determination unit 56 determines that the human body has transitioned from a lying down state to a sitting up state when the voltage output increases beyond a predetermined threshold. Note that the determination unit 56 causes the notification unit 57 to notify the determination result when the detection results of the first pressure sensor 10 and the second pressure sensor 20 match, but is not limited to this. For example, the notification unit 57 may issue a notification based on the detection result of the first pressure sensor 10 without waiting for the detection result of the second pressure sensor 20. In this case, it is desirable to cancel the notification if the determination based on the detection result of the second pressure sensor 20 differs from the determination based on the detection result of the first pressure sensor 10. Furthermore, if the determinations based on the detection results of the first pressure sensor 10 and the second pressure sensor 20 differ, it may be set in advance to give priority to one of the determination results.

[0039] The notification unit 57 has a function of notifying the result of the determination by the determination unit 56. For example, the notification unit 57 can output text information related to the determination result to the monitor 41F or output audio information related to the determination result to a speaker (not shown). The notification unit 57 can also transmit the determination result to an external device, such as a caregiver's mobile phone, via the communication I / F 41E. Here, the notification is made when it is determined that the human body has left the bed and is in a sitting-up state as described below, but it may also be made when it is determined that the human body is in a sleeping state.

[0040] (First Pressure Sensor) Next, the first pressure sensor 10 will be described in detail with reference to Fig. 5 and Fig. 6. Fig. 5 is a front view showing one aspect of the first pressure sensor 10 according to this embodiment. Fig. 6 is a cross-sectional view taken along line VI-VI in Fig. 5.

[0041] 5 and 6 , the first pressure sensor 10 has an internal conductor 11, a piezoelectric body 12, and an external conductor 13. The internal conductor 11 extends in a direction D1. The piezoelectric body 12 covers at least a portion of the internal conductor 11. The external conductor 13 is disposed on the outer periphery of the piezoelectric body 12. When an external force F acts on the piezoelectric body 12, the first pressure sensor 10 generates a first voltage between the internal conductor 11 and the external conductor 13 due to the displacement of the piezoelectric body 12 caused by the external force F. The first voltage indicates the potential difference of the internal conductor 11 relative to the external conductor 13.

[0042] The external force F includes tension, pressure, and bending. The displacement of the piezoelectric body 12 includes restorable deformation (hereinafter referred to as "non-plastic deformation") of the piezoelectric body 12 in response to the external force F. The non-plastic deformation of the piezoelectric body 12 includes partial or total extension and compression of the piezoelectric body 12.

[0043] The pressure sensor 10 is a linear object. The cross-sectional shape of the pressure sensor 10 in a plane perpendicular to the direction D1 is adjusted as appropriate depending on the application of the bioinformation detection device 50, and may be, for example, a circle, an ellipse, a rectangle, a cocoon, a four-leaf clover, a star, or an irregular shape. When the cross-sectional shape of the pressure sensor 10 is circular, the diameter of the pressure sensor 10 is preferably 0.1 mm or more and 10 mm or less. The length of the pressure sensor 10 in the direction D1 is adjusted as appropriate depending on the application of the bioinformation detection device 50, and may be, for example, 1 mm or more and 100 mm or less.

[0044] <Internal Conductor> The internal conductor 11 is a conductor for efficiently detecting an electrical signal from the pressure sensor 10. The internal conductor 11 is preferably a good electrical conductor, such as copper wire, aluminum wire, SUS (Steel Use Stainless Steel) wire, metal wire coated with an insulating film, carbon fiber, resin fiber integrated with carbon fiber, tinsel wire, or organic conductive material. The tinsel wire is formed by spirally winding copper foil around a fiber. The outer diameter of the fiber is adjusted appropriately depending on the desired characteristics of the first pressure sensor 10, and is preferably 0.1 mm or more and 10 mm or less. Among these, tinsel wire or carbon fiber is preferred for the internal conductor 11 from the viewpoints of improving piezoelectric sensitivity and piezoelectric output stability and providing high flexibility, and tinsel wire is particularly preferred from the viewpoint of low electrical resistance.

[0045] <Outer Conductor> The outer conductor 13 is a conductor that pairs with the inner conductor 11 to detect an electrical signal from the first pressure sensor 10. The outer conductor 13 may be disposed on the outer periphery of the piezoelectric body 12 and may cover at least a portion of the piezoelectric body 12. Specifically, the outer conductor 13 may cover a portion of the outer periphery of the piezoelectric body 12, or may cover the entire outer periphery of the piezoelectric body 12. The outer conductor 13 is formed, for example, by winding a long conductor. Examples of the cross-sectional shape of the long conductor include a circular shape, an elliptical shape, a rectangular shape, and an irregular shape. Among these, a rectangular cross-sectional shape is preferable from the viewpoint of being in close contact with the piezoelectric body 12 in a flat plane and efficiently generating a voltage. The material of the long conductor is not particularly limited, and examples of the cross-sectional shape include the following. Examples of long conductors having a rectangular cross section include copper foil ribbons and aluminum foil ribbons, which are obtained by rolling a copper wire with a circular cross section into a flat plate. Examples of long conductors 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, and tinsel wire in which copper foil is spirally wound around fiber. Furthermore, an organic conductive material coated with an insulating material may also be used as the long conductor. Examples of methods for winding the long conductor include a method of spirally winding copper foil around the piezoelectric body 12, a method of braiding copper wire into a cylindrical shape and enveloping the piezoelectric body 12, and a method of enclosing the piezoelectric body 12 in a cylindrical shape.

[0046] <Piezoelectric Body> When an external force F is applied to the piezoelectric body 12, a voltage is generated between the internal conductor 11 and the external conductor 13. The piezoelectric body 12 only needs to cover at least a part of the internal conductor 11, and may cover a part of the outer circumferential surface of the internal conductor 11 or the entire outer circumferential surface of the internal conductor 11.

[0047] In the configuration A of the piezoelectric body 12, the piezoelectric body 12 is formed by winding a long organic piezoelectric body 121 as shown in FIG.

[0048] (Long Organic Piezoelectric Material) The long organic piezoelectric material 121 is made of an organic piezoelectric material and has a piezoelectric constant d １４ It has.

[0049] The long organic piezoelectric material 121 is a long object. Examples of the shape of the long organic piezoelectric material 121 include a ribbon shape and a fiber shape. The ribbon shape is a flat and elongated shape. The fiber shape may be in the form of a monofilament or a multifilament.

[0050] When the long organic piezoelectric material 121 is ribbon-shaped, the width of the long organic piezoelectric material 121 is preferably 0.1 mm or more and 30 mm or less. A width of 0.1 mm or more ensures the strength of the long organic piezoelectric material 121. Furthermore, the manufacturability of the long organic piezoelectric material 121 (for example, manufacturability in the slitting process described below) is also excellent. A width of 30 mm or less improves the degree of freedom (flexibility) of non-plastic deformation of the long organic piezoelectric material 121. When the long organic piezoelectric material 121 is ribbon-shaped, the thickness of the long organic piezoelectric material 121 is preferably 0.001 mm or more and 0.2 mm or less. A thickness of 0.001 mm or more ensures the strength of the long organic piezoelectric material 121. Furthermore, the manufacturability of the long organic piezoelectric material 121 is also excellent. A thickness of 0.2 mm or less improves the degree of freedom (flexibility) of non-plastic deformation in the thickness direction of the long organic piezoelectric material 121. When the long organic piezoelectric material 121 is ribbon-shaped, the ratio of the width of the long organic piezoelectric material 121 to the thickness of the long organic piezoelectric material 121 (hereinafter referred to as the "ratio [width / thickness]") is preferably 2 or more. A ratio [width / thickness] of 2 or more makes the main surfaces of the long organic piezoelectric material 121 clear. Therefore, the long organic piezoelectric material 121 is easily wound around the first outer conductor 13 with the orientation aligned along the length of the long organic piezoelectric material 121. Therefore, the first pressure sensor 10 has excellent piezoelectric sensitivity and excellent stability of the piezoelectric sensitivity.

[0051] When the long organic piezoelectric material 121 is in a fibrous form, the cross-sectional shape of the long organic piezoelectric material 121 may be, for example, a circle, an ellipse, a rectangle, a cocoon shape, a four-leaf shape, a star shape, or an irregular shape. The long axis diameter of the cross section of the long organic piezoelectric material 121 is preferably 0.0001 mm to 10 mm, more preferably 0.001 mm to 5 mm, and even more preferably 0.002 mm to 1 mm. When the cross-sectional shape of the long organic piezoelectric material 121 is circular, the "long axis diameter of the cross section" corresponds to the "diameter," and when the cross-sectional shape of the long organic piezoelectric material 121 is not circular, the "longest width of the cross section" is the longest width of the cross section. When the fiber shape is made of multifilaments, the "long axis diameter of the cross section" is the long axis diameter of the cross section of the multifilament.

[0052] The organic piezoelectric material is a long organic piezoelectric material 121 having a piezoelectric constant d １４ Any material may be used as long as it has the above structure, and examples thereof include an optically active polymer (A). 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.

[0053] "Optically active helical chiral polymer (A1)" refers to a polymer whose molecular structure is helical and has molecular optical activity. Examples of helical chiral polymer (A1) include polylactic acid-based polymers, synthetic polypeptides, cellulose derivatives, polypropylene oxide, and poly(β-hydroxybutyric acid). Examples of polylactic acid-based polymers include homopolymers of L-lactic acid (hereinafter referred to as "PLLA") and homopolymers of D-lactic acid (hereinafter referred to as "PDLA"). PLLA has a left-handed helical molecular structure. PDLA has a right-handed helical molecular structure. Examples of synthetic polypeptides include poly(γ-benzyl glutarate) and poly(γ-methyl glutarate). Examples of cellulose derivatives include cellulose acetate and cyanoethyl cellulose. Details of polylactic acid-based polymers and helical chiral polymers (A1) will be described later.

[0054] "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 viewpoint of piezoelectricity and strength, the optically active polypeptide (A2) preferably has a β-sheet structure. Examples of the optically active polypeptide (A2) include optically active animal proteins. Examples of animal proteins include fibroin and spider silk protein. Examples of fibers made from animal proteins include silk and spider silk. Details of animal proteins will be described later.

[0055] Among these, the organic piezoelectric material preferably contains an optically active polymer (A), particularly a helical chiral polymer (A1) or an optically active polypeptide (A2), from the viewpoints of good piezoelectric properties, processability, and availability. Furthermore, the helical chiral polymer (A1) preferably contains a polylactic acid-based polymer. The optically active polypeptide (A2) preferably contains animal protein. Both the polylactic acid-based polymer and the optically active polypeptide (A2) are non-pyroelectric. By including a polylactic acid-based polymer or an optically active polypeptide (A2) in the organic piezoelectric material, the first pressure sensor 10 exhibits improved stability of piezoelectric sensitivity and piezoelectric output (stability over time or with respect to temperature changes) compared to pressure sensors using pyroelectric PVDF. Furthermore, the optically active polypeptide (A2) exhibits excellent hydrolysis resistance in high-temperature, high-humidity environments. The first pressure sensor 10 containing the optically active polypeptide (A2) exhibits a suppressed decrease in the first voltage, particularly in high-temperature, high-humidity environments, compared to, for example, a first pressure sensor 10 containing a polylactic acid-based polymer. The helical chiral polymer (A) will be described in detail later.

[0056] When the optically active polymer (A) is fibrous, the long organic piezoelectric material 121 may be fibrous or ribbon-shaped. When the optically active polymer (A) is fibrous and the long organic piezoelectric material 121 is fibrous, the organic piezoelectric material may consist solely of the optically active polymer (A). When the optically active polymer (A) is fibrous and the long organic piezoelectric material 121 is ribbon-shaped, the organic piezoelectric material may contain the optically active polymer (A) and a resin. In this case, the organic piezoelectric material may be molded into a ribbon shape using the resin. When the organic piezoelectric material contains multiple fibrous polymer materials (A), the multiple optically active polymers (A) may be bonded together using the resin. The resin may include at least one of a thermoplastic resin and a thermosetting resin. Examples of thermoplastic resins include polymethacrylic resins, polyacrylic resins, aromatic polyether ketones, and polyarylene resins. Examples of polymethacrylic resins include polymethacrylic resins, polyolefin resins, and polymethyl methacrylate resins. Examples of polyacrylic resins include polymethyl acrylate resins. Examples of aromatic polyether ketones include polystyrene resins, polyvinyl acetal resins, polycarbonate resins, and polyphenylene ether resins. Examples of polyarylene resins include polyphenylene oxide resins and polyphenylene sulfide (PPS) resins. These thermoplastic resins may be used alone or in combination of two or more. Examples of thermosetting resins include epoxy resins, phenolic resins, unsaturated polyester resins, thermosetting polyimide resins, bismaleimide triazine resins, and benzoxazine resins. These thermosetting resins may be used alone or in combination of two or more.

[0057] The long organic piezoelectric 121 preferably has the following first composition. In the first composition, the organic piezoelectric material contains an optically active polymer (A), the length direction of the long organic piezoelectric 121 and the main orientation direction of the optically active polymer (A) contained in the long organic piezoelectric 121 are approximately parallel (the direction parallel to the double-headed arrow D2 in FIG. 5 ), and the degree of orientation F of the long organic piezoelectric 121 calculated from X-ray diffraction measurement using the following formula (a) is in the range of 0.5 or more and less than 1.0: Degree of orientation F = (180° - α) / 180° (a), where α represents the half-width of the peak derived from the orientation. The unit of α is degrees.

[0058] The degree of orientation F of the long organic piezoelectric material 121 is an index showing the degree of orientation of the optically active polymer (A) contained in the long organic piezoelectric material 121. The degree of orientation F of the long organic piezoelectric material 121 is the degree of c-axis orientation measured, for example, using a wide-angle X-ray diffractometer (Rigaku Corporation, RINT2550, accessory equipment: rotating sample stage, X-ray source: CuKα, output: 40 kV 370 mA, detector: scintillation counter). The degree of orientation F of the long organic piezoelectric material 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 long organic piezoelectric material 121, the fact that the length direction of the long organic piezoelectric material 121 and the main orientation direction of the optically active polymer (A) contained in the long organic piezoelectric material 121 are approximately parallel also contributes to the expression of piezoelectricity. The fact that the length direction of the long organic piezoelectric material 121 and the main orientation direction of the optically active polymer (A) contained in the long organic piezoelectric material 121 are substantially parallel also has the advantage that the long organic piezoelectric material 121 has excellent tensile strength in the length direction thereof, and therefore the long organic piezoelectric material 121 is less likely to break when being wound spirally around the internal conductor 11.

[0059] "Substantially parallel" means that the angle between the two line segments is 0° or more and less than 30°. The angle between the two line segments is preferably 0° or more and 22.5° or less, more preferably 0° or more and 10° or less, even 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 contains silk or spider silk, which is an example of a fiber made of animal protein, during the production process of the silk or spider silk, the length 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.

[0060] The main orientation direction of the optically active polymer (A) refers to 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 degree of orientation F of the long organic piezoelectric material 121. When the long organic piezoelectric material 121 is produced by stretching a film and slitting the stretched film, the main orientation direction of the optically active polymer (A) in the long organic piezoelectric material 121 refers to the main stretching direction. Here, the main stretching direction refers to the stretching direction in the case of uniaxial stretching, and refers to the stretching direction with a higher stretch ratio in the case of biaxial stretching.

[0061] Hereinafter, a case where the long organic piezoelectric material 121 has the first composition and the optically active polymer (A) is a helical chiral polymer (A1) will be described.

[0062] Examples of methods for manufacturing the long organic piezoelectric material 121 include forming a raw material (e.g., an optically active polymer (A)) into a film to obtain an unstretched film, stretching and crystallizing the unstretched film, and slitting the resulting organic piezoelectric film. Here, "slitting" refers to cutting the organic piezoelectric film into a long shape. Note that either stretching or crystallization may be performed first. Alternatively, a method may be used in which the unstretched film is subjected to pre-crystallization, stretching, and crystallization (annealing) sequentially. The stretching may be uniaxial or biaxial. In the case of biaxial stretching, the stretching ratio in one direction (the main stretching direction) is preferably high. For methods for manufacturing organic piezoelectric films, reference may be made to known documents such as Japanese Patent No. 4934235, WO 2010 / 104196, WO 2013 / 054918, and WO 2013 / 089148. The long organic piezoelectric material 121 will be described later.

[0063] [Configuration A of Piezoelectric Body] Next, configuration A of the piezoelectric body 12 will be described with reference to FIGS. 5 and 6. FIG.

[0064] As shown in FIG. 5 , the elongated organic piezoelectric material 121 is wound counterclockwise (left-handed, i.e., counterclockwise) toward direction D1. Specifically, it is spirally wound in a spiral direction D2 along the outer peripheral surface of the internal conductor 11 toward direction D1 at a spiral angle β1 so as to form no gaps. This wound elongated organic piezoelectric material 121 constitutes the piezoelectric material 12. The "spiral angle β1" refers to the angle between the axial direction AX of the internal conductor 11 and the arrangement direction of the elongated organic piezoelectric material 121 relative to the axial direction AX of the internal conductor 11. 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 "spiral direction D2" refers to the direction in which the elongated organic piezoelectric material 121 is wound toward direction D1.

[0065] Next, the function of the piezoelectric structure A will be described. For example, in the first pressure sensor 10, when tension (stress) is applied in a direction parallel to the axial direction AX, shear strain is applied to the helical chiral polymer (A1) contained in the long organic piezoelectric material 121, and polarization of the helical chiral polymer (A1) occurs in the radial direction of the first pressure sensor 10. If the piezoelectric material 12 of structure A, in which the long organic piezoelectric material 121 is wound in a spiral shape, is considered to be an aggregate of minute regions that can be regarded as flat with respect to the axial direction AX, this polarization direction is such that when a shear force due to tension (stress) is applied to the helical chiral polymer (A1) on the plane of the constituent minute regions, the piezoelectric constant d １４ The direction of the electric field generated by the external force F is approximately the same as the direction of the electric field generated by the external force F. Specifically, the polarization of the helical chiral polymer (A1) occurs in the radial direction of the first pressure sensor 10, as shown by the arrows in FIG. 6, and it is considered that the polarization direction occurs in phase with each other. This makes it easier for the first pressure sensor 10 to effectively generate a first voltage proportional to the external force F. From the above, with the piezoelectric body having the configuration A, the first pressure sensor 10 has excellent piezoelectric sensitivity and excellent stability of the piezoelectric output.

[0066] In the configuration A, when the helical chiral polymer (A1) is PLLA, when tension acts on the first pressure sensor 10 in a direction parallel to the axial direction AX, an electric field (polarization) is generated parallel to the radial direction from the center of the circle of the circular cross section perpendicular to the tension toward the outside. In other words, the first voltage has a positive sign. In the configuration A, when the helical chiral polymer (A1) is PLLA, when pressure acts on the first pressure sensor 10 in a direction parallel to the axial direction AX, an electric field (polarization) is generated parallel to the radial direction from the outside to the center of the circle of the circular cross section perpendicular to the pressure. In other words, the first voltage has a negative sign.

[0067] In the structure A, when the helical chiral polymer (A1) is PDLA, the sign of the first voltage is reversed from that when the helical chiral polymer (A1) is PLLA. Specifically, in the structure A, when the helical chiral polymer (A1) is PDLA, when tension acts on the first pressure sensor 10 in a direction parallel to the axial direction AX, an electric field (polarization) is generated parallel to the radial direction from the outside to the center of the circle of the circular cross section perpendicular to the tension. In other words, the sign of the first voltage is negative. In the structure A, when the helical chiral polymer (A1) is PDLA, when pressure acts on the first pressure sensor 10 in a direction parallel to the axial direction AX, an electric field (polarization) is generated parallel to the radial direction from the center to the outside of the circle of the circular cross section perpendicular to the pressure. In other words, the sign of the first voltage is positive.

[0068] Furthermore, in configuration A, the long organic piezoelectric material 121 is wound counterclockwise in direction D1, but the configuration of the piezoelectric material 12 may also be a configuration in which the long organic piezoelectric material 121 is wound clockwise in direction D1 (hereinafter referred to as "configuration A'").

[0069] In structure A', when the helical chiral polymer (A1) is PLLA, the sign of the first voltage is reversed from that in structure A when the helical chiral polymer (A1) is PLLA. Specifically, in structure A', when the helical chiral polymer (A1) is PLLA, when tension acts on the first pressure sensor 10 in a direction parallel to the axial direction AX, an electric field (polarization) is generated parallel to the radial direction from the outside to the center of the circle of the circular cross section perpendicular to the tension. In other words, the sign of the first voltage is negative. In structure A', when the helical chiral polymer (A1) is PLLA, when pressure acts on the first pressure sensor 10 in a direction parallel to the axial direction AX, an electric field (polarization) is generated parallel to the radial direction from the center to the outside of the circle of the circular cross section perpendicular to the pressure. In other words, the sign of the first voltage is positive.

[0070] In the structure A', when the helical chiral polymer (A1) is PDLA, the sign of the first voltage is reversed from that in the structure A when the helical chiral polymer (A1) is PDLA. Specifically, in the structure A', when the helical chiral polymer (A1) is PDLA, tension applied to the first pressure sensor 10 generates an electric field (polarization) parallel to the radial direction from the center of the circle of the circular cross section perpendicular to the tension toward the outside. In other words, the sign of the first voltage is positive. In the structure A', when the helical chiral polymer (A1) is PDLA, pressure applied to the first pressure sensor 10 generates an electric field (polarization) parallel to the radial direction from the outside to the center of the circle of the circular cross section perpendicular to the pressure. In other words, the sign of the first voltage is negative.

[0071] The piezoelectric body 12 is not limited to the above-described configuration A, and may have other configurations. For example, the piezoelectric body 12 may have a second long organic piezoelectric body wound around it in addition to the long organic piezoelectric body 121. The second long organic piezoelectric body is spirally wound around the outer circumferential surface of the long organic piezoelectric body 121 in the opposite direction to the winding direction of the long organic piezoelectric body 121. The piezoelectric body 12 may also have a braided cord structure wound around it. The braided cord structure is formed by alternately crossing the long organic piezoelectric body 121 and the second long organic piezoelectric body.

[0072] <Adhesive Layer> The first pressure sensor 10 may have an adhesive layer. The adhesive layer is disposed, for example, between the internal conductor 11 and the piezoelectric body 12. This can prevent the relative positional deviation between the piezoelectric body 12 and the internal conductor 11 from occurring even if tension caused by an external force acts on the first pressure sensor 10 in the axial direction AX of the internal conductor 11. The axial direction AX and the direction D1 are parallel. Furthermore, the elongated organic piezoelectric body 121 is more susceptible to tension caused by an external force. Examples of adhesive materials that form 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, and cyanoacrylate adhesives.

[0073] <First Insulator> The first pressure sensor 10 may include a first insulator. The first insulator may be disposed, for example, between the piezoelectric body 12 and the internal conductor 11 or between the piezoelectric body 12 and the external conductor 13. This can further prevent short circuits between the internal conductor 11 and the external conductor 13. The first insulator may be formed, for example, by spirally winding a long member around the outer circumferential surface of the internal conductor 11. The material for the first insulator may be any electrically insulating material, such as polyvinyl 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), and rubber (including elastomer).

[0074] <Second Insulator> The first pressure sensor 10 may have a second insulator. The second insulator is disposed on the outer periphery of the outer conductor 13. The second insulator may cover the entire outer periphery of the outer conductor 13. This makes it possible to electrostatically shield the inner conductor 11, thereby suppressing voltage changes in the first voltage due to the influence of external static electricity. The material of the second insulator may be any material that has electrical insulating properties, and examples of the material include the same materials as those exemplified as the material of the first insulator.

[0075] <Functional Layer> The first pressure sensor 10 may have a functional layer. The functional layer is disposed, for example, between the piezoelectric body 12 and the internal conductor 11 and / or between the piezoelectric body 12 and the external conductor 13. Examples of layers constituting the functional layer (hereinafter referred to as "constituent layers") include an easy-adhesion layer, a hard coat layer, a refractive index adjustment layer, an anti-reflection layer, an anti-glare layer, an easy-slip layer, an anti-blocking layer, a protective layer, an adhesive layer, an antistatic layer, a heat dissipation layer, an ultraviolet absorbing layer, an anti-Newton ring layer, a light scattering layer, a polarizing layer, a gas barrier layer, a hue adjustment layer, and an electrode layer. The functional layer may have a single-layer structure consisting of a single constituent layer, or a multiple-layer structure consisting 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 or different. When the first pressure sensor 10 has a functional layer between the piezoelectric body 12 and the internal conductor 11 and between the piezoelectric body 12 and the external conductor 13, the functional layer between the piezoelectric body 12 and the internal conductor 11 and the functional layer between the piezoelectric body 12 and the external conductor 13 may be the same or different. The film thickness of the functional layer is not particularly limited, and is preferably in the range of 0.01 μm to 10 μm. The material of the functional layer is appropriately selected depending on the function required of the functional layer, and examples thereof include inorganic substances such as metals and metal oxides; organic substances such as resins; and composite compositions containing resins and fine particles. Examples of resins include cured products obtained by curing with temperature or active energy rays.

[0076] (Helical Chiral Polymer (A1)) Next, the helical chiral polymer (A1) will be described.

[0077] 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 a D- or L-isomer 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 long organic piezoelectric material 121 from the viewpoint of further improving the piezoelectricity.

[0078] The optical purity of the helical chiral polymer (A1) is preferably 95.00% ee or more, more preferably 96.00% ee or more, even 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 piezoelectricity of the long organic piezoelectric material 121. By setting the optical purity of the helical chiral polymer (A1) within the above range, it is thought that the packing of the polymer crystals that exhibit piezoelectricity is improved, resulting in increased piezoelectricity.

[0079] The optical purity of the helical chiral polymer (A1) is a value calculated by the following formula: Optical purity (% ee) = 100 × |Amount of L-isomer - Amount of D-isomer| / (Amount of L-isomer + Amount of D-isomer) That is, the optical purity of the helical chiral polymer (A1) is the value obtained by dividing the difference (absolute value) between the amount (% by mass) of the L-isomer of the helical chiral polymer (A1) and the amount (% by mass) of the D-isomer of the helical chiral polymer (A1) by the total amount (% by mass) of the L-isomer of the helical chiral polymer (A1) and the amount (% by mass) of the D-isomer of the helical chiral polymer (A1) and then multiplying this value by 100.

[0080] The amount (% by mass) of the L-isomer of the helical chiral polymer (A1) and the amount (% by mass) of the D-isomer 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.

[0081] -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 long organic piezoelectric material 121 is improved. The 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 when obtaining the long organic piezoelectric material 121 by molding (e.g., extrusion molding, melt spinning) is improved. The Mw of the helical chiral polymer (A1) is preferably 800,000 or less, and more preferably 300,000 or less.

[0082] From the viewpoint of the strength of the long organic piezoelectric material 121, the molecular weight distribution (Mw / Mn) of the helical chiral polymer (A1) is preferably 1.1 or more and 5 or less, more preferably 1.2 or more and 4 or less, and further preferably 1.4 or more and 3 or less.

[0083] The weight-average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the helical chiral polymer (A1) are values ​​measured using gel permeation chromatography (GPC). Here, Mn is the number-average molecular weight of the helical chiral polymer (A1). An example of a method for measuring Mw and Mw / Mn of the helical chiral polymer (A1) by GPC is shown below.

[0084] - GPC measurement device - GPC-100 manufactured by Waters - Column - Shodex LF-804 manufactured by Showa Denko K.K. - Sample preparation - A sample solution with a concentration of 1 mg / ml is prepared by dissolving the long organic piezoelectric material 121 in a solvent (e.g., chloroform) at 40°C. - Measurement conditions - 0.1 ml of the sample solution is introduced into the column in a solvent (chloroform) at a temperature of 40°C and a flow rate of 1 ml / min.

[0085] The sample concentration in the sample solution separated in the column is measured using a differential refractometer. A universal calibration curve is prepared using a polystyrene standard sample, and the weight-average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the helical chiral polymer (A1) are calculated.

[0086] 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 polylactic acid include PURASORB (PD, PL) manufactured by PURAC Corporation, LACEA (H-100, H-400) manufactured by Mitsui Chemicals, Inc., and Ingeo manufactured by NatureWorks LLC. ＴＭ When a polylactic acid-based polymer is used 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.

[0087] The long organic piezoelectric material 121 may contain only one type of helical chiral polymer (A1), or may contain two or more types. The content of the helical chiral polymer (A1) in the long organic piezoelectric material 121 (the total content when two or more types are used) is preferably 80 mass% or more relative to the total amount of the long organic piezoelectric material 121.

[0088] (Polylactic Acid Polymer) Next, the polylactic acid polymer will be described.

[0089] From the viewpoint of increasing the optical purity and improving the piezoelectricity, the polylactic acid polymer preferably has a main chain containing a repeating unit represented by the following formula (1).

[0090]

[0091] The polylactic acid polymer refers to "polylactic acid (a polymer consisting only of repeating units derived from monomers selected from L-lactic acid and D-lactic acid)," "a copolymer of L-lactic acid or D-lactic acid and a compound copolymerizable with said L-lactic acid or D-lactic acid," or a mixture of both. Among polylactic acid polymers, polylactic acid is preferred, with PLLA or PDLA being most preferred.

[0092] Polylactic acid is a polymer in which lactic acid is polymerized through ester bonds and linked together in long chains. Methods for producing polylactic acid include the lactide method, which involves the conversion to lactide; and 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. Block copolymers include homopolymers of L-lactic acid, homopolymers of D-lactic acid, and polymers of at least one of L-lactic acid and D-lactic acid. Graft copolymers include polymers of at least one of L-lactic acid and D-lactic acid.

[0093] 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, and mandelic acid; cyclic esters such as glycolide, β-methyl-δ-valerolactone, γ-valerolactone, and ε-caprolactone; oxalic acid, malonic acid, succinic acid, and glutaric acid. polycarboxylic acids such as methyl acrylate, adipic acid, pimelic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, and terephthalic acid, and anhydrides thereof; 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, and 1,4-hexanedimethanol; polysaccharides such as cellulose; and aminocarboxylic acids such as α-amino acids.

[0094] The "copolymer of L-lactic acid or D-lactic acid and a compound copolymerizable with said L-lactic acid or D-lactic acid" includes a block copolymer or a graft copolymer having a polylactic acid sequence capable of forming a helical crystal.

[0095] The concentration of the structure derived from the copolymer component in the polylactic acid-based polymer is preferably 20 mol % or less. For example, the concentration of the structure derived from the copolymer component is preferably 20 mol % or less relative to the total number of moles of the structure derived from lactic acid and the structure derived from the compound copolymerizable with lactic acid (copolymer component) in the polylactic acid-based polymer.

[0096] Examples of methods for producing polylactic acid polymers include the method of directly dehydrating and condensing lactic acid described in Japanese Patent Laid-Open Nos. 59-096123 and 7-033861; and the method of ring-opening polymerization using lactide, a cyclic dimer of lactic acid, described in U.S. Pat. No. 2,668,182, etc.

[0097] Furthermore, in order to ensure that the polylactic acid-based polymer obtained by each of the above production methods has an optical purity of 95.00% ee or more, for example, when polylactic acid is produced 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 procedure.

[0098] (Animal Protein) Hereinafter, an animal protein, which is an example of the optically active polypeptide (A2), will be described.

[0099] Examples of animal proteins include, in addition to the above-mentioned fibroin and spider silk protein, sericin, collagen, keratin, elastin, etc. Among these, the optically active polypeptide (A2) preferably contains at least one of fibroin and spider silk protein, and more preferably consists of at least one of fibroin and spider silk protein.

[0100] The spider silk protein is not particularly limited as long as it is 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"). "Those derived from natural spider silk proteins" are those that have an amino acid sequence that is the same as or similar to the amino acid repeat sequence found in natural spider silk proteins. Examples of "those derived from natural spider silk proteins" include recombinant spider silk proteins, mutants of natural spider silk proteins, analogs of natural spider silk proteins, and derivatives of natural spider silk proteins.

[0101] From the viewpoint of excellent toughness, the spider silk protein is preferably a major spindle silk protein produced in the major ampullate gland of spiders, or a spider silk protein derived from a major spindle silk protein. Examples of major spindle silk proteins include MaSp1 or MaSp2, which are major ampullate gland spidroins derived from the orb spider (Nephila clavipes), and ADF3 or ADF4, which are derived from the garden spider (Araneus diadematus).

[0102] The spider silk protein may be a minor spindle dragline silk protein produced in the minor ampullate gland of a spider, or a spider silk protein derived from a minor spindle dragline silk protein. Examples of the minor spindle dragline silk protein include MiSp1 and MiSp2, which are minor ampullate gland spidroins derived from the American orb spider (Nephila clavipes).

[0103] Alternatively, the spider silk protein may be a weft protein produced in the flagelliform gland of a spider, or a spider silk protein derived from this weft protein, such as flagelliform silk protein derived from the orb spider (Nephila clavipes).

[0104] An example of a spider silk protein derived from the major spindle dragline silk protein described above is a recombinant spider silk protein containing units of the amino acid sequence shown in formula (2) below. 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 shown in formula (2) below. When the recombinant spider silk protein contains two or more units of the amino acid sequence shown in formula (2) below, the two or more amino acid sequence units may be the same or different.

[0105] REP1-REP2 Formula (2) (In formula (2), REP1 is a polyalanine region composed mainly of alanine and represented by (X1)p, and REP2 is an amino acid sequence consisting of 10 to 200 amino acid residues.)

[0106] In formula (2), REP1 is a polyalanine region represented by (X1)p, which is composed mainly of alanine. REP1 is preferably polyalanine. In (X1)p, p is not particularly limited, but is preferably 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, the total number of alanine residues is preferably 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 number of consecutive alanine residues lined up is preferably two or more, more preferably three or more, even more preferably four or more, and particularly preferably five or more. In addition, in REP1 in formula (2), the number of consecutive alanine residues lined up is preferably 20 or less, more preferably 16 or less, even more preferably 12 or less, and particularly preferably 10 or less.

[0107] In formula (2), REP2 is an amino acid sequence consisting of 10 to 200 amino acid residues. The total number of glycine, serine, glutamine, proline, and alanine residues contained in this amino acid sequence is preferably 40% or more, more preferably 50% or more, and particularly preferably 60% or more, of the total number of amino acid residues.

[0108] An example of the spider silk protein derived from the minor spinule dragline silk protein is a recombinant spider silk protein comprising the amino acid sequence shown in formula (3) below.

[0109] 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 represents 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.)

[0110] In REP3, Z represents any one amino acid, and is particularly preferably an amino acid selected from the group consisting of Ala, Tyr and Gln.

[0111] The above-mentioned recombinant spider silk proteins (e.g., recombinant spider silk proteins containing units of the amino acid sequence shown in formula (2), recombinant spider silk proteins containing the amino acid sequence shown in formula (3), etc.) can be produced using a host transformed with an expression vector containing a gene encoding the native spider silk protein to be recombined.

[0112] From the viewpoint of piezoelectricity, the long organic piezoelectric material 121 preferably includes fibers made of an optically active polypeptide (A2). Examples of fibers made of an optically active polypeptide (A2) include fibers made of an animal protein having optical activity. Examples of fibers made of an animal protein having optical activity include silk, wool, mohair, cashmere, camel, llama, alpaca, vicuna, angora, and spider silk. From the viewpoint of piezoelectricity, the fibers made of an optically active polypeptide (A2) preferably include at least one of silk and spider silk, and more preferably consist of at least one of silk and spider silk.

[0113] Examples of silk include raw silk, refined silk, regenerated silk, and fluorescent silk. Raw silk or refined silk is preferred, with refined silk being particularly preferred. Refined silk refers to silk obtained by removing sericin from raw silk, which has a double structure of sericin and fibroin, and refining refers to the process of removing sericin from raw silk. Raw silk is a dull white color, but removing sericin from raw silk (i.e., refining) changes the color from dull white to a lustrous silvery white. Refining also enhances the softness of the silk.

[0114] From the viewpoint of piezoelectricity, it is preferable that the long organic piezoelectric material 121 contains long fibers made of the optically active polypeptide (A2). The reason for this is thought to be that long fibers transmit stress applied to the first pressure sensor 10 to the piezoelectric material 12 more easily than short fibers. "Long fibers" refers to fibers that are long enough to be continuously wound around the first pressure sensor 10 from one end to the other in the longitudinal direction. Silk, wool, mohair, cashmere, camel, llama, alpaca, vicuna, angora, and spider silk all fall under the category of long fibers. Among long fibers, silk and spider silk are preferable from the viewpoint of piezoelectricity.

[0115] When the long organic piezoelectric material 121 includes the above-mentioned fiber, it is preferable that the long organic piezoelectric material 121 includes at least one thread made of at least one of the above-mentioned fibers. When the long organic piezoelectric material 121 includes the above-mentioned thread, it can be configured such that the long organic piezoelectric material 121 is made of one of the above-mentioned threads, or such that the long organic piezoelectric material 121 is an assembly of a plurality of the above-mentioned threads. The above-mentioned thread may be a twisted thread or an untwisted thread, but from the viewpoint of piezoelectricity, it is preferable that the thread has a twist number of 500 T / m or less (i.e., a twisted thread with a twist number of 500 T / m or less or an untwisted thread (twist number 0 T / m)). Examples of the untwisted thread include a single raw thread and an assembly of a plurality of raw threads.

[0116] (Long Organic Piezoelectric Material) Next, the long organic piezoelectric material 121 will be further described.

[0117] <Stabilizer> The long organic piezoelectric material 121 preferably further contains a stabilizer (B) 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 and a weight average molecular weight of 200 to 60,000. This can further improve the moist heat resistance.

[0118] As the stabilizer (B), the "stabilizer (B)" described in paragraphs 0039 to 0055 of WO 2013 / 054918 can be used.

[0119] Compounds containing a carbodiimide group in one molecule (carbodiimide compounds) that can be used as the stabilizer (B) include monocarbodiimide compounds, polycarbodiimide compounds, and cyclic carbodiimide compounds. Suitable monocarbodiimide compounds include dicyclohexylcarbodiimide and bis-2,6-diisopropylphenylcarbodiimide. Furthermore, polycarbodiimide compounds produced by various methods can be used. Polycarbodiimide compounds produced by conventional methods (e.g., U.S. Pat. No. 2,941,956; Japanese Patent Publication No. 47-33279; J. Org. Chem. 28, 2069-2075 (1963); Chemical Review 1981, Vol. 81, No. 4, pp. 619-621) can be used. Specifically, the carbodiimide compounds described in Japanese Patent Publication No. 4,084,953 can also be used. Examples of polycarbodiimide compounds include poly(4,4'-dicyclohexylmethanecarbodiimide), poly(N,N'-di-2,6-diisopropylphenylcarbodiimide), and poly(1,3,5-triisopropylphenylene-2,4-carbodiimide). Cyclic carbodiimide compounds can be synthesized based on the method described in JP 2011-256337 A. Commercially available carbodiimide compounds may be used, and examples thereof include B2756 (trade name) manufactured by Tokyo Chemical Industry Co., Ltd., Carbodilite (registered trademark) LA-1 (trade name) manufactured by Nisshinbo Chemical Inc., and Stabaxol P, Stabaxol P400, and Stabaxol I (all trade names) manufactured by Rhein Chemie.

[0120] Examples of compounds containing an isocyanate group in one molecule (isocyanate compounds) 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, and isophorone diisocyanate.

[0121] Examples of compounds containing an epoxy group in one molecule (epoxy compounds) 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 novolac epoxy resins, cresol novolac epoxy resins, and epoxidized polybutadiene.

[0122] As described above, the weight-average molecular weight of the stabilizer (B) is 200 to 60,000, more preferably 200 to 30,000, and even more preferably 300 to 18,000. If the molecular weight is within the above range, the stabilizer (B) becomes more mobile, and the moist heat resistance improving effect is more effectively achieved. The weight-average molecular weight of the stabilizer (B) is particularly preferably 200 to 900. A weight-average molecular weight of 200 to 900 is almost the same as a number-average molecular weight of 200 to 900. Furthermore, when the weight-average molecular weight is 200 to 900, the molecular weight distribution may be 1.0. In this case, "weight-average molecular weight of 200 to 900" can be simply rephrased as "molecular weight of 200 to 900."

[0123] When the long organic piezoelectric material 121 contains a stabilizer (B), the long organic piezoelectric material 121 may contain only one type of stabilizer, or may contain two or more types of stabilizers. When the long organic piezoelectric material 121 contains a stabilizer (B), the content of the stabilizer (B) is preferably 0.01 to 10 parts by mass, more preferably 0.01 to 5 parts by mass, even more preferably 0.1 to 3 parts by mass, and particularly preferably 0.5 to 2 parts by mass, per 100 parts by mass of the helical chiral polymer (A1). When the content of the stabilizer (B) is 0.01 parts by mass or more, the moist heat resistance is further improved. Furthermore, when the content is 10 parts by mass or less, the decrease in transparency is further suppressed.

[0124] A preferred embodiment of the stabilizer (B) is a combination of a stabilizer (B1) having one or more functional groups selected from the group consisting of carbodiimide groups, epoxy groups, and isocyanate groups and having a number average molecular weight of 200 to 900, and a stabilizer (B2) having two or more functional groups selected from the group consisting of carbodiimide groups, epoxy groups, and isocyanate groups per molecule and having a weight average molecular weight of 1,000 to 60,000. The weight average molecular weight of the stabilizer (B1) having a number average molecular weight of 200 to 900 is approximately 200 to 900, and the number average molecular weight and weight average molecular weight of the stabilizer (B1) are approximately the same. When the stabilizer (B1) and the stabilizer (B2) are used in combination as stabilizers, it is preferable to contain a large amount of the stabilizer (B1) from the viewpoint of improving transparency. Specifically, from the viewpoint of achieving both transparency and moist heat resistance, it is preferable that the amount of stabilizer (B2) is in the range of 10 parts by mass or more and 150 parts by mass or less, and more preferably in the range of 50 parts by mass or more and 100 parts by mass or less, per 100 parts by mass of stabilizer (B1).

[0125] Specific examples of the stabilizer (B) (stabilizers (B-1) to (B-3)) are shown below.

[0126]

[0127] The following lists the compound names, commercially available products, etc. for stabilizers (B-1) to (B-3). Stabilizer (B-1): The compound name is bis-2,6-diisopropylphenylcarbodiimide. The weight-average molecular weight (equivalent to the simple "molecular weight" in this example) is 363. Commercially available products include "Stabaxol I" manufactured by Rhein Chemie and "B2756" manufactured by Tokyo Chemical Industry Co., Ltd. Stabilizer (B-2): The compound name is poly(4,4'-dicyclohexylmethanecarbodiimide). Commercially available products with a weight-average molecular weight of approximately 2000 include "Carbodilite (registered trademark) LA-1" manufactured by Nisshinbo Chemical Inc. Stabilizer (B-3): The compound name is poly(1,3,5-triisopropylphenylene-2,4-carbodiimide). Commercially available products include "Stabaxol P" manufactured by Rhein Chemie, which has a weight-average molecular weight of about 3,000, and "Stabaxol P400" manufactured by Rhein Chemie, which has a weight-average molecular weight of 20,000.

[0128] <Other Components> The long organic piezoelectric element 121 may contain other components as needed. 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; and stabilizers other than the stabilizer (B). Examples of inorganic fillers and crystal nucleating agents include the components described in paragraphs 0057 to 0058 of WO 2013 / 054918.

[0129] (Orientation degree F) As described above, the orientation degree F of the long organic piezoelectric material 121 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 long organic piezoelectric material 121 is 0.5 or more, many molecular chains of the helical chiral polymer (A1) (e.g., polylactic acid molecular chains) are aligned in the stretching direction, resulting in a higher rate of oriented crystal formation and enabling the development of higher piezoelectric properties. If the orientation degree F of the long organic piezoelectric material 121 is less than 1.0, the longitudinal tear strength is further improved.

[0130] (Crystallization degree) The crystallinity of the long organic piezoelectric material 121 is a value measured by the above-mentioned X-ray diffraction measurement (wide-angle X-ray diffraction measurement). The crystallinity of the long organic piezoelectric material 121 is preferably 20% or more and 80% or less, more preferably 25% or more and 70% or less, and even more preferably 30% or more and 60% or less. A crystallinity of 20% or more maintains high piezoelectricity. A crystallinity of 80% or less maintains high transparency of the long organic piezoelectric material 121. A crystallinity of 80% or less makes it easy to manufacture the long organic piezoelectric material 121, for example, because whitening and breakage are unlikely to occur when the organic piezoelectric film that serves as the raw material for the long organic piezoelectric material 121 is produced by stretching. Furthermore, since the crystallinity is 80% or less, for example, when the raw material of the long organic piezoelectric material 121 (e.g., polylactic acid) is melt-spun and then stretched to produce a fiber with high flexibility, the long organic piezoelectric material 121 can be easily produced.

[0131] An example of the operation of the bioinformation detection device 50 will be described below. In this embodiment, the bioinformation detection device 50 is disposed on, for example, a bed 200. A human body lies down, sits, and stands up on the bioinformation detection device 50. In this state, when tension is applied to the bioinformation detection device 50 due to biosignals (body movement, periodic vibrations (pulse, breathing, etc.)) emitted from the human body, polarization occurs in the helical chiral polymer (A1) contained in the pressure sensor, generating a potential proportional to the tension. This potential changes over time in accordance with the biosignal emitted from the human body. For example, if the biosignal emitted from the human body is a periodic vibration such as a pulse or breathing, the potential generated in the bioinformation detection device 50 also changes periodically. The change over time in the potential generated in accordance with the application of tension to the bioinformation detection device 50 is acquired as a voltage signal by the measurement module. The acquired change over time in the potential (voltage signal) is a composite wave of multiple biosignals (pulse wave signal (heart rate signal), breathing signal, and body movement signal). This composite wave is separated into frequencies by Fourier transform to generate separated signals, and each of the separated signals is then subjected to an inverse Fourier transform to obtain a corresponding biological signal.

[0132] For example, if the biosignal emitted by the subject is a composite wave of a heartbeat signal and a respiratory signal, the potential generated by the application of tension to the bioinformation detection device 50 changes periodically over time. Generally, a person's pulse rate is 50 to 100 beats per minute, with a period of 0.83 Hz to 1.67 Hz. Generally, a person's breathing rate is 12 to 20 beats per minute, with a period of 0.20 Hz to 0.33 Hz. Generally, a person's body movement is 10 Hz or higher. Based on these guidelines, the composite wave of multiple biosignals can be separated into individual biosignals. Furthermore, a velocity pulse wave signal can also be obtained from the heartbeat signal. Separating the composite wave of multiple biosignals into individual biosignals can be performed, for example, using a biosignal notification program, using Fourier transform and inverse Fourier transform.

[0133] In this manner, the composite wave of a plurality of biological signals can be separated into each of the plurality of biological signals.

[0134] Furthermore, biosignal data may be generated based on at least one of the biosignals separated as described above. The biosignal data is not particularly limited as long as it is calculated based on the biosignals. Examples of the biosignal data include the number of biosignals per unit time and the average number of past biosignals.

[0135] Next, an example of a detection result when the biological information detection device 50 of the present disclosure is used will be described with reference to FIGS. 7 and 8. FIG.

[0136] Figure 7 shows an example of the detection results of the first pressure sensor 10 and the second pressure sensor 20 when transitioning from the initial state, which is a sitting state (a state in which the upper body is raised and sitting on the bed), to a sleeping state (a state in which the body is lying on its back), and then transitioning from the sleeping state to the sitting state.

[0137] As shown in Figure 7, when the patient transitions from a sitting up state to a sleeping state around 30 seconds, the first pressure sensor 10 first detects a pressure fluctuation exceeding the threshold (the graph moves up and down). Then, about one second later, the second pressure sensor 20 detects a pressure fluctuation exceeding the threshold (the graph moves down). The first pressure sensor 10 detects large pressure changes for several seconds, but once the sleeping state stabilizes, the pressure detection becomes slight. After detecting pressure from the human body, the second pressure sensor 20 continues to detect pressure.

[0138] In this example, the determination unit 56 can first determine that the human body has transitioned from the initial state, the sitting state, to the sleeping state based on the detection result of the first pressure sensor 10 around 30 seconds. That is, the determination unit 56 can determine that the human body has transitioned to the sleeping state, which is a state different from the initial state, the sitting state, by detecting a fluctuation in the voltage output of the first pressure sensor 10 exceeding a threshold value. Then, the determination unit 56 can determine that the human body has transitioned from the sitting state to the sleeping state and is maintaining the sleeping state based on the detection result of the second pressure sensor 20. That is, the determination unit 56 can determine that the human body has transitioned to the sleeping state, which is a state different from the initial state, the sitting state, by detecting a decrease in the voltage output of the second pressure sensor 20 exceeding a threshold value, and that the human body is maintaining the sleeping state by continuing to detect the decreased voltage output. In this example, the determination unit 56 can determine that the human body has transitioned from the initial state, the sitting state, to the sleeping state based on the detection result of the first pressure sensor 10 and the detection result of the second pressure sensor 20.

[0139] Additionally, when the person transitions from the sleeping state to the sitting up state around 60 seconds, the first pressure sensor 10 first detects a pressure fluctuation exceeding the threshold (the graph moves up and down). Then, approximately two seconds later, the second pressure sensor 20 detects a pressure fluctuation exceeding the threshold (the graph rises). The first pressure sensor 10 detects large pressure changes for several seconds, but after the sitting up state stabilizes, the detected pressure becomes slight. Because the human body is no longer resting on the second pressure sensor 20, the detected pressure becomes slight and continues to be detected.

[0140] In this example, the determination unit 56 can first determine whether the human body has gotten out of bed or is sitting up based on the detection results of the first pressure sensor 10. That is, by detecting a fluctuation in the voltage output of the first pressure sensor 10 exceeding a threshold value, the determination unit 56 can determine that the human body has transitioned to a sitting up state, which is a state different from the sleeping state, which was the previous determination result by the determination unit 56 made around 30 seconds ago. Then, based on the detection results of the second pressure sensor 20, the determination unit 56 can determine that the human body has transitioned from a sleeping state to a sitting up state and is maintaining the sitting up state. That is, by detecting an increase in the voltage output of the second pressure sensor 20 exceeding a threshold value, the determination unit 56 can determine that the human body has transitioned from a sleeping state to a sitting up state, and by continuing to detect the increased voltage output, the determination unit 56 can determine that the human body is maintaining the sitting up state. In this example, the determination unit 56 can determine that the human body has transitioned from a sleeping state to a sitting up state based on the detection results of the first pressure sensor 10 and the detection results of the second pressure sensor 20.

[0141] In other words, whether the human body is in an upright state or a sleeping state is ultimately determined based on the detection results of the second pressure sensor 20, but since the detection by the first pressure sensor 10 is earlier than the detection by the second pressure sensor, the primary determination is made based on the detection results of the first pressure sensor 10.

[0142] Figure 8 shows an example of the detection results of the first pressure sensor 10 and the second pressure sensor 20 when transitioning from the initial sleeping state (lying on one's back) to a right rolling state (sleeping on one's right side), from the right rolling state to the sleeping state, from the sleeping state to the left rolling state (sleeping on one's left side), from the left rolling state to the sleeping state, and from the sleeping state to a sitting up state (sitting on the bed with the upper body raised).

[0143] As shown in Figure 8, when the patient transitions from the sleeping state to the right tossing state around 29 seconds, the first pressure sensor 10 first detects a pressure fluctuation exceeding the threshold (the graph moves up and down). Then, approximately one second later, the second pressure sensor 20 detects a pressure fluctuation exceeding the threshold (the graph rises). The first pressure sensor 10 detects large pressure changes for several seconds, but after the patient stabilizes in the right tossing state, the pressure detection becomes slight. Because the pressure from the human body is less when the patient is tossing to the right than when the patient is sleeping, the second pressure sensor 20 detects less pressure than when the patient is sleeping, and then continues to detect the pressure.

[0144] In this example, the determination unit 56 can first determine that the human body has transitioned from the initial state, the sleeping state, to a state other than the sleeping state, such as a sitting up state or a turning over state, based on the detection result of the first pressure sensor 10 around 29 seconds. That is, the determination unit 56 can determine that the human body has transitioned to a state other than the sleeping state, such as a sitting up state or a turning over state, by detecting a fluctuation in the voltage output of the first pressure sensor 10 exceeding a threshold value. Then, the determination unit 56 can determine that the human body has transitioned from the sleeping state to a turning over state and is maintaining the turning over state based on the detection result of the second pressure sensor 20. That is, the determination unit 56 can determine that the human body has transitioned from the sleeping state to a turning over state by detecting an increase in the voltage output of the second pressure sensor 20 exceeding a threshold value, and that the human body is maintaining the turning over state by continuing to detect the increased voltage output. Here, the reason why it is determined that the human body has transitioned from the sleeping state to the turning state rather than the sitting up state based on the detection result of the second pressure sensor 20 is that the detection result of the second pressure sensor 20 does not increase to the voltage output of the sitting up state, but is not the voltage output of the sleeping state, so it is determined that the human body is in the turning state, which is a pressure between the sleeping state and the sitting up state. In this example, the determination unit 56 can determine that the human body has transitioned from the sleeping state, which is the initial state, to the turning state, based on the detection result of the first pressure sensor 10 and the detection result of the second pressure sensor 20.

[0145] Additionally, around 60 seconds into the sleep state, when the patient transitions from a right rollover state to a sleeping state, the first pressure sensor 10 first detects a pressure fluctuation exceeding the threshold (the graph moves up and down). Then, approximately one second later, the second pressure sensor 20 detects a pressure fluctuation exceeding the threshold (the graph moves down). The first pressure sensor 10 detects large pressure changes for several seconds, but once the sleeping state stabilizes, the detected pressure becomes slight. After detecting pressure from the human body, the second pressure sensor 20 continues to detect pressure.

[0146] In this example, the determination unit 56 can first determine, based on the detection result of the first pressure sensor 10, that the human body has transitioned from the tossing state to a sleeping state or an upright state other than the tossing state. That is, by detecting a fluctuation in the voltage output of the first pressure sensor 10 exceeding the threshold, the determination unit 56 can determine that the human body has transitioned to a sleeping state or an upright state, which is a state different from the tossing state, which was the previous determination result by the determination unit 56 made around 29 seconds above. Then, based on the detection result of the second pressure sensor 20, the determination unit 56 can determine that the human body has transitioned from the tossing state to a sleeping state and is maintaining the sleeping state. That is, the determination unit 56 can determine that the human body has transitioned from the tossing state to a sleeping state by detecting a decrease in the voltage output of the second pressure sensor 20 exceeding the threshold, and that the human body is maintaining the sleeping state by continuing to detect the decreased voltage output. In this example, the determination unit 56 can determine that the human body has transitioned from a turning-over state to a sleeping state based on the detection results of the first pressure sensor 10 and the detection results of the second pressure sensor 20 .

[0147] Additionally, around 90 seconds into the test, when the patient transitions from the sleeping state to the left-side rolling state, the first pressure sensor 10 first detects a pressure fluctuation exceeding the threshold (the graph moves up and down). Then, approximately one second later, the second pressure sensor 20 detects a pressure fluctuation exceeding the threshold (the graph rises). The first pressure sensor 10 detects large pressure changes for several seconds, but once the patient stabilizes in the right-side rolling state, the pressure detection becomes slight. Because the pressure from the human body is less when the patient rolls over to the right than when the patient is sleeping, the second pressure sensor 20 detects less pressure than when the patient is sleeping, and then continues to detect the pressure.

[0148] In this example, the determination unit 56 can first determine that the human body has transitioned from the initial state, the sleeping state, to a state other than the sleeping state, such as a sitting up state or a turning over state, based on the detection result of the first pressure sensor 10 around 90 seconds. That is, the determination unit 56 can determine that the human body has transitioned to a sitting up state or a turning over state, which are states different from the sleeping state, which is the result of the previous determination by the determination unit 56 made around 60 seconds, by detecting a fluctuation in the voltage output of the first pressure sensor 10 exceeding the threshold value. Then, the determination unit 56 can determine that the human body has transitioned from the sleeping state to a turning over state and is maintaining the turning over state, based on the detection result of the second pressure sensor 20. That is, the determination unit 56 can determine that the human body has transitioned from the sleeping state to a turning over state by detecting an increase in the voltage output of the second pressure sensor 20 exceeding the threshold value, and that the human body is maintaining the turning over state by continuing to detect the increased voltage output. Here, the reason why it is determined that the human body has transitioned from the sleeping state to the turning state rather than the sitting up state based on the detection result of the second pressure sensor 20 is that the detection result of the second pressure sensor 20 does not increase to the voltage output of the sitting up state, but is not the voltage output of the sleeping state, so it is determined that the human body is in the turning state, which is a pressure between the sleeping state and the sitting up state. In this example, the determination unit 56 can determine that the human body has transitioned from the sleeping state to the turning state based on the detection result of the first pressure sensor 10 and the detection result of the second pressure sensor 20.

[0149] Additionally, around 120 seconds into the sleep state, when the patient transitions from a right rollover state to a sleeping state, the first pressure sensor 10 first detects a pressure fluctuation exceeding the threshold (the graph moves up and down). Then, approximately one second later, the second pressure sensor 20 detects a pressure fluctuation exceeding the threshold (the graph moves down). The first pressure sensor 10 detects large pressure changes for several seconds, but once the sleeping state stabilizes, the detected pressure becomes slight. After detecting pressure from the human body, the second pressure sensor 20 continues to detect pressure.

[0150] In this example, the determination unit 56 can first determine, based on the detection result of the first pressure sensor 10, that the human body has transitioned from the tossing state to a sleeping state or a sitting state other than the tossing state. That is, by detecting a fluctuation in the voltage output of the first pressure sensor 10 exceeding a threshold, the determination unit 56 can determine that the human body has transitioned to a sleeping state or a sitting state, which is a state different from the tossing state, which was the previous determination result by the determination unit 56 made around 90 seconds above. Then, based on the detection result of the second pressure sensor 20, the determination unit 56 can determine that the human body has transitioned from the tossing state to a sleeping state and is maintaining the sleeping state. That is, the determination unit 56 can determine that the human body has transitioned from the tossing state to a sleeping state by detecting a decrease in the voltage output of the second pressure sensor 20 exceeding a threshold, and that the human body is maintaining the sleeping state by continuing to detect the decreased voltage output. In this example, the determination unit 56 can determine that the human body has transitioned from a turning-over state to a sleeping state based on the detection results of the first pressure sensor 10 and the detection results of the second pressure sensor 20 .

[0151] Furthermore, when the person transitions from the sleeping state to the sitting up state around 150 seconds, the first pressure sensor 10 first detects a pressure fluctuation exceeding the threshold (the graph moves up and down). Then, about one second later, the second pressure sensor 20 detects a pressure fluctuation exceeding the threshold (the graph rises). The first pressure sensor 10 detects large pressure changes for several seconds, but after the sitting up state stabilizes, the pressure detection becomes slight. Because the human body is no longer resting on the second pressure sensor 20, the pressure detection becomes slight and the pressure detection continues.

[0152] In this example, the determination unit 56 can first determine that the human body has transitioned from the sleeping state to a state other than the sleeping state, such as a sitting up state or a turning over state, based on the detection result of the first pressure sensor 10 around 150 seconds. That is, by detecting a fluctuation in the voltage output of the first pressure sensor 10 exceeding the threshold, the determination unit 56 can determine that the human body has transitioned to a sitting up state or a turning over state, which is a state different from the sleeping state, which was the previous determination result by the determination unit 56 made around 120 seconds. Then, based on the detection result of the second pressure sensor 20, the determination unit 56 can determine that the human body has transitioned from the sleeping state to the sitting up state and is maintaining the sitting up state. That is, the determination unit 56 can determine that the human body has transitioned from the sleeping state to the sitting up state by detecting an increase in the voltage output of the second pressure sensor 20 exceeding the threshold, and that the human body is maintaining the sitting up state by continuing to detect the increased voltage output. Here, the reason why it is determined that the person has transitioned from a sleeping state to a sitting up state, rather than a turning-over state, based on the detection result of the second pressure sensor 20 is that the detection result of the second pressure sensor 20 has increased to a voltage output in a state where the pressure of the human body is hardly detected, and so it is determined that the person is in a sleeping state. In this example, the determination unit 56 can determine that the person has transitioned from a sleeping state to a sitting up state based on the detection result of the first pressure sensor 10 and the detection result of the second pressure sensor 20.

[0153] In this example, the first pressure sensor 10 detects a pressure fluctuation exceeding the threshold value around 130 seconds. Therefore, the determination unit 56 can determine that the patient has transitioned from the sleeping state to a turning-over state or a sitting-up state based on the detection result of the first pressure sensor 10. However, because the second pressure sensor 20 does not detect a pressure fluctuation exceeding the threshold value, the determination unit 56 can determine that the pressure fluctuation around 130 seconds does not indicate a transition from the sleeping state to another turning-over state or a sitting-up state.

[0154] (Note) As in the present embodiment, by determining whether a person has left the bed based on the detection results of both the first pressure sensor 10 and the second pressure sensor 20, it is possible to reliably determine whether a person has left the bed. For example, the second pressure sensor 20, which is a resistive pressure sensor, alone cannot distinguish whether the pressure is being applied by a human body or an object. That is, the second pressure sensor 20 cannot distinguish whether a person has fallen asleep when luggage is placed on the bed 200. Furthermore, the second pressure sensor 20 cannot distinguish whether a person has left the bed when luggage is removed from the bed 200. Therefore, by combining the detection results of the second pressure sensor 20 with the detection results of the pulse wave signal and respiratory signal obtained from the first pressure sensor 10, which is a biological sensor, it is possible to reliably detect whether a person has left the bed.

[0155] (Other) The bed apparatus 100 may be a so-called electric bed powered by electricity and capable of changing the angle of the bed plate 220 of the upper body side region 200A. The bed apparatus 100 may also be equipped with a sensor, such as an acceleration sensor, that can detect the angle of the bed plate 220 of the bed apparatus 100, more specifically, the angle of the bed plate 220 of the upper body side region 200A. In other words, if the angle of the upper body side region 200A changes, the pressure applied to the pressure sensor may fluctuate, making it possible to reliably detect bed exit even when the angle changes. Furthermore, by combining biometric information obtained from the first pressure sensor 10, which is a biometric sensor, with angle information obtained from the acceleration sensor, it is possible to detect changes in load and biometric information due to the bed angle. This makes it possible to calculate optimal sleep onset angles and breathing angles, and to suggest these optimal sleep onset angles and breathing angles to the user of the bed apparatus 100.

[0156] In the above-described embodiment, the first pressure sensor 10 and the second pressure sensor 20 are configured as an integrated sensor unit 32, but this is not limiting. For example, the first pressure sensor 10 and the second pressure sensor 20 may be configured as separate sensor units, and may be arranged parallel to each other on the upper surface of the floorboard 220 to detect pressure at different points on the human body.

[0157] The biological information detection device 50 of this embodiment may be incorporated into an existing bed 200 to form the bed device 100, or may be installed and used on a carpet, flooring, tatami, etc. The biological information detection device 50 installed on a carpet, flooring, tatami, etc. also achieves the same effects as the above-mentioned bed device 100. Since the biological information detection device 50 of this embodiment can be combined with existing bedding, it is possible to use existing bedding as is and to prevent deterioration of sleeping comfort.

[0158] In the bed apparatus 100 of this embodiment, the greater the foaming ratio of the foamed rubber or resin used as the cushioning material 37, the greater the variations in density and rubber hardness, resulting in greater variations in the sensor sensitivity of the first pressure sensor 10. Furthermore, materials such as natural rubber exhibit significant changes in rubber hardness over time, resulting in greater variations in sensor sensitivity. EPDM foam, which exhibits less variation over time, is preferred. Furthermore, when using the cushioning material 37 in the bed 200, flame resistance is often required. In such cases, the cushioning material 37 is preferably made of foamed plastic foam mixed with various flame-retardant additives, or polyvinyl chloride foam or polyimide foam, which are flame-retardant resins themselves.

[0159] Furthermore, in the bed apparatus 100 of each embodiment, the support plate 36 is not necessarily required, and a buffer material 37 may be provided on the bed board 220. The insulating member 38, which is the covering member in this embodiment, is, but is not limited to, an adhesive tape or an adhesive film. For example, the insulating member 38 may be in the form of a laminate, a heat-shrinkable tube, or a covering made of an insulating material (for example, wrapping PET or fluorine tape around the piezoelectric line), etc.

[0160] In the above embodiment, the processes related to the detection unit 55, the determination unit 56, and the notification unit 57, which are executed by loading software (programs) by the CPU 41A, may be executed by various processors other than a CPU. Examples of such processors include programmable logic devices (PLDs) (such as field-programmable gate arrays (FPGAs)) whose circuit configuration can be changed after manufacture, and dedicated electrical circuits, such as application-specific integrated circuits (ASICs), which are processors with circuit configurations specifically designed to execute specific processes. Furthermore, the various processes may be executed by one of these various processors, or by a combination of two or more processors of the same or different types (e.g., multiple FPGAs, or a combination of a CPU and an FPGA). Furthermore, the hardware structure of these various processors is, more specifically, an electrical circuit combining circuit elements such as semiconductor devices.

[0161] In the above embodiment, the execution programs are pre-stored (installed) in the storage 41D, but this is not limiting. Each program may be provided in a form recorded on a recording medium such as a CD-ROM (Compact Disc Read Only Memory), a DVD-ROM (Digital Versatile Disc Read Only Memory), or a USB (Universal Serial Bus) memory. The programs may also be downloaded from an external device via a network.

[0162] The disclosure of Japanese Patent Application No. 2023-221559, filed on December 27, 2023, is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards mentioned herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference.

[0163] The following supplementary notes are further provided regarding one embodiment of the technology disclosed in the present application.

[0164] (Appendix 1) A biological information detection device having: a linear first sensor provided on a support installed at a predetermined location and detecting radial pressure applied by a living body supported on the support; and a second sensor detecting pressure applied by the living body supported on the support.

[0165] (Supplementary Note 2) The biological information detection device according to Supplementary Note 1, wherein the first sensor is a sensor capable of acquiring biological information by pressure.

[0166] (Supplementary Note 3) The biological information detection device according to Supplementary Note 1 or Supplementary Note 2, wherein the second sensor is a resistive pressure sensor.

[0167] (Appendix 4) The support is a bed on which the living body lies, and the first sensor and the second sensor are positioned at least in the upper body region when the living body lies on the bed. A biological information detection device described in any one of Appendices 1 to 3.

[0168] (Appendix 5) The biological information detection device according to any one of Appendices 1 to 4, wherein the support is a bed on which the living body lies, and the first sensor and the second sensor are arranged along the width direction of the bed.

[0169] (Supplementary Note 6) The biological information detection device according to any one of Supplementary Note 1 to Supplementary Note 5, wherein the first sensor and the second sensor are arranged parallel to each other.

[0170] (Appendix 7) A biological information detection device described in any one of Appendices 1 to 6, wherein the first sensor and the second sensor are arranged on the support along a pressure-receiving surface that receives pressure from the living body, and the second sensor is installed at a location farther from the living body than the first sensor.

[0171] (Appendix 8) A biometric information detection device described in any one of Appendices 1 to 7, wherein the first sensor comprises: a long conductor; and a long piezoelectric element wound spirally in one direction around the conductor.

[0172] (Supplementary Note 9) The first sensor has a piezoelectric constant d １４ The biological information detection device according to claim 8, wherein the organic piezoelectric element is a long organic piezoelectric element including an organic piezoelectric material having the formula:

[0173] (Supplementary Note 10) The biological information detection device according to Supplementary Note 8 or Supplementary Note 9, wherein the first sensor is an optically active helical chiral polymer (A).

[0174] (Appendix 11) The biological information detection device according to Appendix 10, wherein the helical chiral polymer (A) is polylactic acid.

Claims

1. A biological information detection device comprising: a linear first sensor provided on a support installed at a predetermined location and detecting a radially applied pressure received from a living body supported by the support; and a second sensor supported by the support and detecting the pressure received from the living body supported by the support.

2. The biological information detection device according to claim 1, wherein the first sensor is a sensor capable of acquiring biological information by pressure.

3. The biological information detection device according to claim 1, wherein the second sensor is a resistive pressure sensor.

4. The support is a bed on which the living body lies, and the first sensor and the second sensor are arranged at least in the upper body side region when the living body lies on the bed. The biological information detection device according to claim 1.

5. The support is a bed on which the living body lies, and the first sensor and the second sensor are arranged along the width direction of the bed. The biological information detection device according to claim 1.

6. The biological information detection device according to claim 1, wherein the first sensor and the second sensor are arranged parallel to each other.

7. The first sensor and the second sensor are provided along a pressure receiving surface that receives pressure from the living body on the support, and the second sensor is installed at a location farther from the living body than the first sensor. The biological information detection device according to claim 1.

8. The first sensor includes a long conductor and a long piezoelectric body spirally wound in one direction around the conductor. The biological information detection device according to claim 1.

9. The first sensor is a long organic piezoelectric body including an organic piezoelectric material having a piezoelectric constant d １４ The biological information detection device according to claim 8, which is an organic piezoelectric body including an organic piezoelectric material having a piezoelectric constant d 10. The first sensor is a helical chiral polymer (A) having optical activity. The biological information detection device according to claim 8 or claim 9.

11. The helical chiral polymer (A) is polylactic acid. The biological information detection device according to claim 10.

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