Biometric information detection device and seating determination device

Abstract

This biological information detection device is provided with: a bag-shaped first member which is filled with air and which has a first surface and a second surface facing one another; a bag-shaped second member which is filled with air and which has a third surface and a fourth surface facing one another, the third surface facing the second surface; a module provided with a first pusher that is located at the center of the first surface as seen from the direction of stacking of the first member and the second member, and a second pusher that is in contact with at least the center of the fourth surface; and a detector for detecting the difference between the gas pressure inside the first member and the gas pressure inside the second member. The distance between the first surface and a fifth surface, which is a surface of the first pusher and faces the first surface, decreases going from the peripheral edge toward the center. Vibrations can be transmitted between the first surface and the fifth surface.　

Description

[Technical Field]

[0001] The present invention relates to a biological information detection device and a seating determination device, and more particularly to a biological information detection device and a seating determination device that detect vital vibrations, for example. [Background technology]

[0002] There are known biological information detection devices that detect vibrations of the human body's vital signs, such as pulse waves and breathing (for example, Patent Documents 1 to 6). It is also known that a bag-shaped member filled with air is used to detect the vibrations of vital signs by detecting the air pressure inside the bag-shaped member (for example, Patent Documents 4 and 5). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-219341 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-218068 [Patent Document 3] Japanese Patent Application Laid-Open No. 2006-42904 [Patent Document 4] Japanese Patent Application Publication No. 2018-47862 [Patent Document 5] Japanese Patent Application Laid-Open No. 2009-82585 [Patent Document 6] Japanese Patent Application Laid-Open No. 2009-104599 Summary of the Invention [Problem to be solved by the invention]

[0004] However, highly sensitive vibration detectors are susceptible to external vibration disturbances. For example, large external vibration disturbances such as drive noise occur when a vehicle is running. The signal saturates when the output signal from the sensor element that detects the vibration is amplified and converted to an analog voltage. This is because the amplifier output is within the range of the power supply voltage, and if the output signal from the sensor element is large, the amplified signal exceeds the range of the power supply voltage. When the signal saturates, it becomes impossible to detect minute vital vibrations inherent in large vibrations.

[0005] The present invention has been made in view of the above-mentioned problems, and has an object to improve detection accuracy. [Means for solving the problem]

[0006] The present invention provides a biometric information detection device comprising: a bag-shaped first member having a first surface and a second surface facing each other and filled with gas; a bag-shaped second member having a third surface and a fourth surface facing each other, the third surface facing the second surface, and filled with gas; a module comprising a first pressing portion located in the center of the first surface when viewed in the stacking direction of the first member and the second member; and a second pressing portion contacting at least the center of the fourth surface; and a detector that detects the difference between the gas pressure in the first member and the gas pressure in the second member, wherein the distance between the first surface and a fifth surface of the first pressing portion facing the first surface becomes shorter from the peripheral portion toward the center, and vibrations can be transmitted between the first surface and the fifth surface.

[0007] In the above configuration, the surface of the first pressing portion facing the first surface may have a central portion that protrudes more toward the first surface than a peripheral portion.

[0008] In the above configuration, the first surface may have a central portion that protrudes toward the first pressing portion relative to a peripheral edge portion.

[0009] In the above configuration, the second surface and the third surface may be in contact with each other.

[0010] In the above configuration, the module may be configured to include a separator provided between the second surface and the third surface and in contact with the peripheral edges of the second surface and the third surface, and the second surface and the third surface may be separated by the separator.

[0011] In the above configuration, the module may include a support member that surrounds the first member and the second member and connects the first pressing portion and the second pressing portion.

[0012] In the above configuration, the module can be configured to include a plate-shaped member located away from the first pressing portion on the opposite side of the first member from the first pressing portion, and an axial core member that connects the center of the plate-shaped member to the center of the first pressing portion and has a planar area smaller than the planar area of ​​the plate-shaped member.

[0013] In the above configuration, the first surface, the second surface, the third surface, and the fourth surface may be arranged in a direction substantially perpendicular to the vertical direction.

[0014] In the above configuration, the module may include a third member provided on the opposite side of the first member from the first pressing portion, and a third pressing portion located on the periphery of the first surface between the first surface and the third member and in contact with the first surface and the third member, and may be configured such that vibrations can be transmitted between the first surface and the third member via the first pressing portion.

[0015] In the above configuration, the module may include a support member that surrounds the first member and the second member and connects the third member and the second pressing portion.

[0016] In the above configuration, the module may be configured to include a separator provided between the second surface and the third surface and in contact with the peripheral edges of the second surface and the third surface, and the second surface and the third surface may be separated by the separator.

[0017] In the above configuration, the module may be configured to include a plate-shaped member disposed on the opposite side of the third member from the first member and spaced apart from the third member, and an axial core member connecting the center of the plate-shaped member to the center of the third member.

[0018] The present invention provides a biological information detection device comprising: a module including a bag-shaped first member having a first surface and a second surface facing each other and filled with gas; a bag-shaped second member having a third surface and a fourth surface facing each other, the third surface facing the second surface, and filled with gas; a first pressing portion contacting at least the center of the first surface; a second pressing portion contacting at least the center of the fourth surface; a plate-shaped member provided on the opposite side of the first pressing portion from the first member and away from the first pressing portion; an axial member connecting the center of the plate-shaped member to the center of the first pressing portion and having a planar area smaller than the planar area of ​​the plate-shaped member; and a detector for detecting the difference between the gas pressure in the first member and the gas pressure in the second member.

[0019] The present invention is a biometric information detection device comprising: a bag-shaped first member having a first surface and a second surface facing each other and filled with gas; a bag-shaped second member having a third surface and a fourth surface facing each other, the third surface facing the second surface, and filled with gas; a module including a first pressing portion in contact with at least the center of the first surface; and a second pressing portion in contact with at least the center of the fourth surface; and a detector that detects the difference between the gas pressure in the first member and the gas pressure in the second member, wherein the first surface, the second surface, the third surface, and the fourth surface are arranged in a direction approximately perpendicular to the vertical direction.

[0020] In the above configuration, the second surface and the third surface may be in contact with each other.

[0021] In the above configuration, the module may be configured to be installed in a seat of a vehicle.

[0022] The present invention is a seating determination device comprising the above-mentioned biometric information detection device and a determination unit that determines whether or not a passenger is seated in a seat of a vehicle in which the module is installed based on the output of the detector. [Effects of the Invention]

[0023] According to the present invention, it is possible to improve detection accuracy. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 1 is a schematic diagram illustrating a module and a differential pressure sensor according to a first embodiment. [Figure 2] FIG. 2 is a block diagram illustrating the detection device according to the first embodiment. [Figure 3] FIG. 3 is a diagram illustrating an example in which the module according to the first embodiment is arranged on a seat. [Figure 4] 4(a) is a plan view of the pad in Example 1, FIG. 4(b) is a cross-sectional view taken along line AA in FIG. 4(a), and FIGS. 4(c) and 4(d) are cross-sectional views of the pad and the pressing portion. [Figure 5] FIG. 5 is a diagram showing pressure changes relative to the amount of vibration applied to the pad. [Figure 6] 6(a) and 6(b) are cross-sectional views of the module in the first embodiment. [Figure 7] 7(a) to 7(c) are cross-sectional views of the module in the first embodiment. [Figure 8] 8(a) and 8(b) are diagrams showing another example of the first embodiment. [Figure 9] 9(a) and 9(b) are diagrams showing another example of the first embodiment. [Figure 10] FIG. 10 is a cross-sectional view of a module according to a second embodiment. [Figure 11] 11(a) to 11(d) are plan views of a module according to a second embodiment. [Figure 12] FIG. 12 shows the detector output signal versus time in Experiment 1. [Figure 13] 13(a) and 13(b) are cross-sectional views of modules according to first and second modifications of the second embodiment, respectively. [Figure 14] FIG. 14 is a cross-sectional view of a module according to a third modification of the second embodiment. [Figure 15] FIG. 15 is a cross-sectional view of a module according to a third embodiment. [Figure 16] 16(a) to 16(d) are plan views of a module according to a third embodiment. [Figure 17] FIG. 17 shows the detector output signal versus time in Experiment 2. [Figure 18] FIG. 18(a) is a cross-sectional view of the module according to the fourth embodiment, and FIGS. 18(b) and 18(c) are plan views of the module according to the fourth embodiment. [Figure 19] FIG. 19(a) is a diagram showing the output signal of the sensor 20a over time in Experiment 3, and FIG. 19(b) is a diagram showing the spectrum obtained by Fourier transforming the output signal for period 72 in FIG. 19(a). [Figure 20] FIG. 20 is a cross-sectional view of a module according to a first modification of the fourth embodiment. [Figure 21] 21(a) is a cross-sectional view of a module in Comparative Example 5, and FIG. 21(b) is a cross-sectional view of a module in Example 5. As shown in FIG. [Figure 22] 22(a) and 22(b) are cross-sectional views of a car seat in which a module according to the fifth embodiment is installed. [Figure 23] 23(a) to 23(d) are diagrams showing the output signal of the differential pressure sensor over time in Experiment 4. [Figure 24] 24(a) to 24(g) are diagrams showing the results of the spectral analysis of FIG. 23(a) in Experiment 4. [Figure 25] 25(a) to 25(g) are diagrams showing the results of the spectral analysis of FIG. 23(b) in Experiment 4. [Figure 26]26(a) to 26(g) are diagrams showing the results of the spectral analysis of FIG. 23(c) in Experiment 4. [Figure 27] 27(a) to 27(g) are diagrams showing the results of the spectral analysis of FIG. 23(d) in Experiment 4. [Figure 28] 28(a) and 28(b) are flowcharts showing the processing of the processing unit in the sixth embodiment. [Figure 29] FIG. 29 is a flowchart showing a detection method in the sixth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0025] Hereinafter, an embodiment will be described with reference to the drawings. [Example]

[0026] [Explanation of the two stacked pads and differential pressure sensor] Example 1 is an example of a biological information detection device. FIG. 1 is a schematic diagram showing a module and a differential pressure sensor in the biological information detection device in Example 1. As shown in FIG. 1, module 10 includes pad 12 (first member) and pad 14 (second member). Pad 12 overlaps pad 14. Pads 12 and 14 may be in contact with each other or may be spaced apart and not in contact with each other. Pads 12 and 14 are bag-like members having spaces 11 and 13 filled with a gas such as air. Pads 12 and 14 are bags made of a resin material, and the pressure in spaces 11 and 13 is maintained at a pressure that will not collapse under the weight of a human body. Pads 12 and 14 may be made of a flexible material or a relatively hard material as long as the pressure in spaces 11 and 13 changes due to vibration. Pads 12 and 14 are made of a resin such as polyethylene or polycarbonate. The outer shape of pads 12 and 14 is a thin rectangular parallelepiped, for example, the shape of a small air mattress or cushion, or the shape of a circular or oval edible pie dough in a plan view, and pads 12 and 14 have a hollow, bag-like structure. As mentioned above, spaces 11 and 13 within pads 12 and 14 may be filled with gases or liquids other than air. In other words, the vibrations mentioned above are fluctuations in pressure, and this force is applied to pads 12 and 14. The target biological information (vital vibrations) is then detected by a differential pressure sensor, which will be described below.

[0027] The differential pressure sensor 20 includes a housing 22, a diaphragm 24, and a sensor element 25. A force applied to the diaphragm 24 causes distortion in the diaphragm 24. The sensor element 25 converts the distortion of the diaphragm 24 into an electrical signal. Here, the differential pressure sensor 20 is shown in which a piezoelectric element is mounted on the diaphragm 24 as the sensor element 25. The differential pressure sensor 20 may be any differential pressure sensor that detects pressure. The sensor element 25 may be a capacitance sensor, an electret condenser microphone, a piezo-resistance sensor, a differential transformer, or the like.

[0028] The housing 22 is a rigid body, and spaces 21 and 23 are defined within the housing 22, with the vibrating membrane 24 as the boundary. The differential pressure sensor 20 may be a commercially available differential pressure sensor having a sensor element 25 other than a piezoelectric element and a built-in vibrating membrane 24. In this case, the sensor element 25 is provided with a case (or housing) to protect the sensor body. Instead of the vibrating membrane 24, the size of the opening surrounded by the protrusion 22a may be the same as the size of the case for the sensor element 25, and the case for the sensor element 25 may be tightly inserted (fitted) into the opening. In this way, the sensor element 25 and the protrusion 22a may define the spaces 21 and 23. It is preferable that the shapes and sizes of the spaces 21 and 23 are, for example, almost the same. The shape of the housing 22 is, for example, a cylindrical or box-like shape, and the housing 22 is made primarily of metal or resin. The housing 22 in FIG. 1 is, for example, cylindrical, with a circular upper surface, a circular lower surface, and side surfaces connecting the upper and lower surfaces.

[0029] [Vital vibration and external vibration] Generally, there are cases where a vibration to be detected is difficult to detect due to disturbance vibrations (hereinafter also referred to as noise) entering from the surroundings. Example 1 is capable of detecting the desired vibration with a simple configuration in such an environment. In the examples of this specification, the vibration to be detected is, as an example, vital vibrations of a vehicle occupant, such as breathing or pulse. On the other hand, disturbance vibrations are vibrations that enter as noise when detecting vital vibrations. In the case of a vehicle, disturbance vibrations are drive noise or road noise. Drive noise includes, for example, road noise, mechanical sounds such as drive noise, air conditioning breeze, engine noise (motor noise in an EV), and human body movement sounds. Road noise is noise generated when a vehicle driven by an engine or motor travels on a road, and is generally noise from the road and tires. Body movement sounds are noise generated by the driver's movements. In the following description, the vehicle will be driven by an engine.

[0030] In the embodiments of this specification, an example will be described in which vital vibrations are detected while a vehicle is traveling. However, there are various cases in which detection of vital vibrations of a human body is required. For example, vital vibrations from a human body in a wheelchair, bed, or mobile bed, or vital vibrations from a person running or walking, etc. When an object picked up by a person or a person moves, noise is superimposed on the vibrations to be detected, as with a person in a vehicle, making it difficult to detect the vital vibrations of the human body.

[0031] The purpose of the embodiments of this specification is to efficiently detect vibrations that you want to detect in an environment where there are both vibrations you want to detect and external disturbance vibrations that you want to eliminate. For example, there are various cases where you might want to detect vital vibrations of a person in a noisy factory, or the sound of a good engine or processing motor.

[0032] [Silent case and noisy case] For example, when considering the driving of a car, there are cases where loud noises, such as road noise, occur and cases where no road noise occurs. The former is called the N (Noise) case, as it is a case where disturbance vibrations such as road noise occur, and the latter is called the S (Silent) case, as it is a quiet environment.

[0033] These S and N cases are classified as follows from the perspective of extracting the vital signs of the car occupants: Case 1: The car engine is off and the passengers are sitting in their seats. Case 2: A passenger is sitting in the seat and the car's engine is running, but the car is parked and not moving. Case 3: A passenger sits in the seat, the engine is running, and the car is traveling slowly on a road, especially on flat asphalt. Case 4: A passenger is sitting in the seat, the car's engine is running, and the vehicle is traveling at high speed, on a gravel road, or on a road with large bumps.

[0034] The following explanations and experiments can be broadly divided into two cases. When large noises such as road noise and external vibrations are present, these are cases 3 and 4, and are called N cases. When other noises are present but are small, cases 1 to 3 are called S cases. Here, case 3 may be either the S case or the N case, depending on the noise level.

[0035] [Case] Here, the housings are divided into two types. The first is housing 52 (see FIG. 7(c)) that houses pads 12 and 14. The second is housing 22 that houses sensor element 25 that detects pressure and vibrations within pads 12 and 14.

[0036] As mentioned above, the housing 22 that houses the sensor element 25 is described as a rigid body. A rigid body is a virtual object whose volume and shape do not change, and is made of, for example, strong plastic or metal. Using a rigid body for the housing 22 minimizes the amount of noise from outside the housing 22 that enters the housing 22. The housing 22 is a box made of a rigid material and surrounded by a strong plate. Anything that can eliminate bending components when external vibrations are applied is described as a rigid body. This point will be discussed later. On the other hand, the housing 52 that houses the pads is divided into two parts, and when vibrations are transmitted from the top, bottom, or side plates, it is more flexible than a rigid body.

[0037] [Sensor element for differential pressure sensor] Each type of sensor element 25 has its own advantages and disadvantages. Piezoelectric sensors have high resolution and detection accuracy. However, because they are mounted on a vibrating part, there is a possibility of poor connection over time. On the other hand, capacitive sensors are designed to generate capacitance between two opposing electrodes. For example, the capacitance changes when at least one of the electrodes vibrates. Since no element is located on the diaphragm or diaphragm, there is little possibility of poor connection due to adhesion or other factors. Thus, while each type of sensor element 25 has its own advantages and disadvantages, it is possible to use various sensor elements 25 in the differential pressure sensor 20. Therefore, the usage pattern should be selected taking into account the installation environment. Note that the following explanation mainly uses piezoelectric elements.

[0038] [Differential pressure sensor] Vibrating membrane 24 is provided to separate spaces 21 and 23. That is, the lower surface of the inner wall defining space 21 is the upper surface of vibrating membrane 24, and the upper surface of the inner wall defining space 23 is the lower surface of vibrating membrane 24. An inner wall corresponding to the side wall of housing 22 is provided with a ring-shaped protrusion 22a of a predetermined width that protrudes inward along the entire periphery. The periphery of vibrating membrane 24 is joined to the upper surface of protrusion 22a. The entire periphery of vibrating membrane 24 is fixed to protrusion 22a. Vibrating membrane 24 may also be provided on the lower surface of protrusion 22a. In addition, connecting pipes are provided on the side wall of housing 22 corresponding to spaces 21 and 23. These pipes are referred to as connecting portions 28 and 29 herein. These connecting portions 28 and 29 are provided to connect tubes 26 and 27. Therefore, space 21 is connected (i.e., communicates) with space 11 in pad 12 via connection 28 and tube 26 (first tube). Space 23 is connected to space 13 in pad 14 via connection 29 and tube 27 (second tube). Spaces 21 and 23 are filled with air. Note that spaces 21 and 23 may be filled with a fluid such as a gas or liquid other than air. A sensor element 25 is provided on the upper surface of vibrating membrane 24. Since vibrating membrane 24 first receives vibrations (e.g., pressure vibrations) from pads 12 and 14 and then transmits them to sensor element 25, sensor element 25 is provided so as not to overlap protrusion 22a.

[0039] When vibrations are applied to pads 12 and 14, pressure is applied to pads 12 and 14, causing pads 12 and 14 to deform, as described above. As a result, the gas pressure in spaces 11 and 13 changes. The change in gas pressure is transmitted to spaces 21 and 23. When the vibrations applied to pads 12 and 14 have the same phase and amplitude, vibrating membrane 24 barely vibrates. Vibrations corresponding to the difference between the vibrations applied to pads 12 and 14 are transmitted to vibrating membrane 24. Sensor element 25 detects this vibration (e.g., pressure vibration) of vibrating membrane 24 and outputs a detection signal to signal processing device 30 (e.g., circuit). In this way, differential pressure sensor 20 detects the difference between the gas pressure in pad 12 (i.e., the pressure of the gas filling space 11) and the gas pressure in pad 14 (i.e., the pressure of the gas filling space 13).

[0040] [Sensor unit] FIG. 2 is a block diagram showing a biological information detection device according to a first embodiment. As shown in FIG. 2, the detection device 100 includes a module 10 and a sensor unit 31. The differential pressure sensor 20 outputs a detection signal to a circuit component 35. The circuit component 35 includes, for example, a preamplifier (analog amplifier) ​​and amplifies the detection signal. A printed circuit board may be provided inside the housing 22 of the differential pressure sensor 20, and the circuit component 35 may be provided on this printed circuit board, or may be provided outside the housing 22. The preamplifier may be provided as a single chip or a single package. Furthermore, if the preamplifier is equivalent to or smaller than the sensor element 25, the preamplifier may be provided on the front or back surface of the diaphragm 24.

[0041] When a preamplifier with a desired power supply voltage (e.g., 3.3 V) converts and amplifies the output of sensor element 25, the output signal will not saturate as long as the amplified signal is within the range of the power supply voltage. Large vibrations, such as external disturbance vibrations, produce a large output from sensor element 25, causing the preamplifier's output signal to saturate. This can prevent detection of small vibrations, such as vital signs. The embodiments of this specification suppress the vibrations propagating to pads 12 and 14 in various ways, thereby suppressing saturation of the output signal and enabling detection of the desired vibrations. As described in the specification, similar methods can be used to suppress saturation of sensor element 25, even if the sensor element is an element other than a piezoelectric element.

[0042] The signal processed by the circuit component 35 is output to the signal processing device 30. The signal processing device 30 includes an amplifier 32, a processing unit 34, a memory 36, and an output unit 38. The amplifier 32 amplifies the output signal from the circuit component 35. The gain of the amplifier 32 is variable. The processing unit 34 is a processor such as a CPU (Central Processing Unit), which converts the amplified signal from analog to digital (AD), digitally processes the converted digital signal, and performs calculations (or computations) to extract vital information such as respiration and pulse waves. The memory 36 is a volatile or non-volatile memory, and stores programs executed by the processing unit 34 and data being processed. The output unit 38 outputs the vital information calculated by the processing unit 34 to an external device. The vital information is output via, for example, wireless or wired communication.

[0043] [Car seat] FIG. 3 is a diagram showing an example in which the module 10 in the first embodiment is disposed in a car seat. When a passenger sits in the car seat 41, the right direction is the +X direction, the forward direction is the +Y direction, and the upward direction is the +Z direction. As shown in FIG. 3, the car seat 41 in a four-wheel vehicle includes a base 42, a seat cushion 44, and a seat back 46. The base 42 is made of, for example, a metal member. The thighs and buttocks of a passenger, such as a driver, come into contact with the seat cushion 44, and the neck, back, and waist of the passenger come into contact with the seat back 46. The module 10 shown in FIG. 1 is disposed in the seat cushion 44. The seat cushion 44 is covered with a seat cloth (not shown). The seat cushion 44 is made of a soft resin, such as a foam resin such as urethane. When the passenger sits in the car seat 41, as shown in FIG. 3, the passenger's right buttocks is positioned over the module 10. Vibrations of the occupant's vital signs are transmitted to the module 10 via the right buttock and the seat cushion 44. The module 10 may be placed so as to overlap the left buttock or the thigh. The module 10 may also be placed on the seat back 46 so as to overlap the neck, back, or waist.

[0044] The module 10 may be installed in a bicycle saddle, a desk chair, a bed, a mattress, a bracelet, and the like. While the car seat 41 used in a four-wheeled vehicle is described here as an example, the car seat 41 shown in FIG. 3 can also be used in other moving objects, such as motorcycles, trains, airplanes, cranes, bulldozers, and rockets. These vehicles may be engine-driven or motor-driven. The seat may also be a household sofa or a chair with just a cushion, omitting the seat back.

[0045] The module 10 described below is embedded in a chair. The modules 10 include modules without an axial core member and a plate-like member as shown in Figures 7(a) to 7(c), and modules with an axial core member and a plate-like member as shown in Figures 8(a) and 8(b), but all of the modules 10 are embedded in a seat or the like as shown in Figure 3.

[0046] In the N case, where external vibrations such as drive noise are present, and the S case, which is quiet, a study was conducted to detect the pressure difference between the pads 12 and 14 using the differential pressure sensor 20 and extract vital vibrations using this module 10.

[0047] [Pushing part: The center and periphery of the pad that the pushing part presses] First, we considered the pads 12 and 14 and the pressing portions 16 and 18 that press the pads 12 and 14. In the description of Example 1, except for the description of Figures 9(a) and 9(b), the pads 12 and 14 correspond to the first member and the second member, respectively. The upper surface 12a and the lower surface 12b of the pad 12 correspond to the first surface and the second surface that face each other, respectively. The upper surface 14a and the lower surface 14b of the pad 14 correspond to the third surface and the fourth surface that face each other, respectively. The pressing portions 16 and 18 correspond to the first pressing portion and the second pressing portion, respectively.

[0048] Fig. 4(a) is a plan view of the pad in Example 1, and Fig. 4(b) is a cross-sectional view taken along line AA in Fig. 4(a). Figs. 4(b) to 4(d) explain how to press pads 12 and 14. In reality, the pressing portion 16 of pad 12 in Fig. 4(c) is in contact with the upper surface 12a of pad 12, and the pressing portion 18 of pad 14 in Fig. 4(d) is in contact with the lower surface 14b of pad 14. Since both are explained in Fig. 4(b), both the upper surface 12a and the lower surface 14b are shown above pads 12 and 14, and both the lower surface 12b and the upper surface 14a are shown below pads 12 and 14.

[0049] First, to explain the positional relationship between the pressing portions 16 and 18, the central portion 63 and the peripheral portion 64 will be described. As shown in Figures 4(a) and 4(b), the pad 12 has a central portion 63 and a peripheral portion 64 outside the central portion 63. The upper surface 12a of the pad 12 or the lower surface 14b of the pad 14 is pressed by the pressing portions 16 and 18, and therefore the central portion 63 and the peripheral portion 64 are used to define the positions of the upper surface 12a and the lower surface 14b with which the pressing portions 16 and 18 abut.

[0050] The central portion 63 is a region including the center 65 of the upper surface 12a and the lower surface 14b. The center 65 is, for example, the center point (e.g., the center of gravity) of the planar shape of the upper surface 12a and the lower surface 14b. As will be described later, the position where the pressing portion 16 abuts on the upper surface 12a is preferably the center 65 of the upper surface 12a of the pad 12, but vibrations cannot be detected even if the pressing portion 16 is shifted from the center 65. In this sense, the central portion 63 in this specification is a range in which vibrations can be detected and a portion having a width. The peripheral portion 64 of the upper surface 12a or the lower surface 12b is roughly within a range of 20% to 30% of the planar area of ​​the upper surface 12a or the lower surface 14b. As shown in FIG. 4(a), the central portion 63 may be a region separated from the peripheral portion 64, or the entire area inside the peripheral portion 64 may be the central portion, as in region 63a.

[0051] [Point and Area Pressing] Two pressing methods, point pressing and area pressing, will be explained using Figure 4(b). The area where the pressing portion 16 or 18 contacts the upper surface 12a or lower surface 14b is referred to as the contact area. The first pressing method, as indicated by arrow 80a, is when the area including the center 65 of the upper surface 12a or lower surface 14b of the pad 12 or 14 is pressed with a small contact area. This pressing method is sometimes referred to as "point pressing" in this specification. Geometrically, a point does not have an area, but in this specification, it refers to a case where the contact area is smaller than that of the pressing portion 18 in Figure 4(d), as in the pressing portion 16 in Figure 4(c).

[0052] The second pressing method is when the upper surface 12a or the lower surface 14b is pressed over a wide area including the center 65, from the left arrow 80b to the right arrow 80b in FIG. 4(b). For example, when the upper surface 12a or the lower surface 14b is pressed over almost the entire area from the left arrow 80b to the right arrow 80b, when the peripheral edge 64 of the upper surface 12a or the lower surface 14b is pressed in a ring shape, or when the planar shape of the upper surface 12a or the lower surface 14b is rectangular, when the four corners of the peripheral edge 64 are pressed. This pressing method is sometimes referred to as "surface pressing" in this specification. Also, as shown in FIG. 4(d), when the pressing portion 18 presses the lower surface 14b with a contact area larger than the contact area of ​​the pressing portion 16, which is a point pressing, for example, when the pressing portion 16 or 18 presses an area of ​​more than half of the planar area of ​​the upper surface 12a or the lower surface 14b, respectively. This case is also sometimes called "face pressing."

[0053] Returning to FIG. 4(b), when the central portion 63 of the upper surface 12a or the lower surface 14b is pressed, as indicated by arrow 80a, the pads 12 and 14 have a high leaf spring property. Vibrations can be detected even if the pressed point is slightly off center 65. Therefore, as shown in FIG. 4(c), even if a small force, such as a force equivalent to a vital vibration, is applied to the pressing portion 16, which has a point pressing structure, a large change in pressure on the pad 12 or 14 can be achieved. Furthermore, as long as the portion of the upper surface 12a or the lower surface 14b pressed by the pressing portion 16 or 18 is within the range of the aforementioned central portion 63, the vital vibration can be detected relatively strongly, although the effect will vary slightly.

[0054] Now, let us consider the surface pressing structure. This is the case when the peripheral edge 64 of the upper surface 12a or lower surface 14b is pressed, as indicated by the left and right arrows 80b in FIG. 4(b) (see FIGS. 10 to 11(d)). The leaf spring properties of the pad 12 or 14 decrease from the center 63 of the pad 12 or 14 toward the peripheral edge 64. In other words, in the case of surface pressing, the upper surface 12a of the pad 12 or the lower surface 14b of the pad 14 is less likely to vibrate up and down compared to point pressing. In other words, the surface pressing structure can be thought of as slightly suppressing the vibration of the pad 12 or 14, thereby reducing the penetration of the vibration into the pad 12 or 14. For example, in the case of an N-type case, the surface pressing structure is important because the differential pressure sensor 20 reduces the pressure difference between the pads 12 and 14 due to external vibrations, enabling efficient detection of vital vibrations. As shown in Figure 4(b), one pad (e.g., pad 12 in Figure 4(c)) has high responsiveness, while the other pad (e.g., pad 14 in Figure 4(d)) has low responsiveness. It is important to differentiate the responsiveness of the two pads in this way.

[0055] In the case of the S case, when only small vibrations such as vital vibrations are applied and no large disturbance vibrations are applied, one of the pads 12 is designed as a point-pressure structure, as shown in Figure 4(c), to increase the responsiveness of the pad 12 and detect vital vibrations. As shown in Figure 4(d), the other pad 14 is designed as an area-pressure structure, suppressing the vibration of the pad 14. As a result, the pressure difference between the two pads 12 and 14 is increased.

[0056] On the other hand, when a large amount of vibration, such as external disturbance vibration, is present, as in the N case, the responsiveness of the two pads 12 and 14 can be approximately equal. In other words, with the surface pressing structure of pad 14, large vibrations are transmitted from below, and the pressure vibrations within pad 14 are small. With the point pressing structure of pad 12, the transmitted vibrations are smaller than those of pad 14, and the pressure vibrations within pad 12 are small. As a result, the pressure difference between pads 12 and 14 is small. Although the magnitude of the pressure vibrations of pads 12 and 14 will never be exactly the same, if the pressure difference is detected, the output signal from differential pressure sensor 20 due to external disturbance vibrations will be small. This prevents the output signal from becoming a signal that saturates the preamplifier. Details will be described later.

[0057] 4(c) and 4(d) are cross-sectional views of the pad and the pressing portion. FIG. 5 is a diagram showing the change in pressure relative to the amount of vibration applied to the pad. The amount of vibration corresponds to the force applied to the pads 12 and 14, and is indicated by the size of the arrows. As shown in FIG. 4(c) and 4(d), the pressing portions 18 and 16 are divided into two types. In FIG. 4(c), the contact area between the pressing portion 16 and the upper surface 12a is smaller than the contact area between the pressing portion 18 and the lower surface 14b. In FIG. 4(d), the pressing portion 18 contacts the lower surface 14b over a wide area up to the peripheral edge 64 of the lower surface 14b.

[0058] In FIG. 5, the area 61 where the vibration amount is small corresponds to the S case. The area 62 where the vibration amount is large corresponds to the N case. As shown in FIG. 4(c), when the narrow pressing portion 16 presses the upper surface 12a of the pad 12 (arrow 80), the pressing portion 16 mainly presses the center of the upper surface 12a. The dotted line 75c in FIG. 5 indicates the change in pressure in the space 11 relative to the amount of vibration when the pressing portion 16 presses the upper surface 12a of the pad 12. The central portion 63 has high leaf spring properties, so the change in pressure relative to the amount of vibration is large. As the amount of vibration when the pressing portion 16 presses the upper surface 12a increases, the change in pressure also increases. In other words, if a small vibration is received using a point pressing structure, the change in pressure within the pad 12 can be made large. Furthermore, even if the point where the pressing portion 16 presses the upper surface 12a is somewhat displaced from the center 65, vibration can be detected within the range where the pressing portion 16 presses the upper surface 12a in the central area.

[0059] As shown in FIG. 4(d), when the wide pressing portion 18 presses the underside 14b of the pad 14 (arrow 81), the pressing portion 18 presses the area of ​​the underside 14b from the central portion 63 to the peripheral portion 64. The contact area of ​​the pressing portion 18 needs only to be larger than the contact area of ​​the pressing portion 16; the pressing portion 18 does not need to press down to the peripheral portion 64. For example, the contact area of ​​the pressing portion 18 can be selected within a range from more than half the area of ​​the underside 14b to the entire area of ​​the underside 14b. When the pressing portion 18 presses the entire area of ​​the underside 12b from the central portion 63 to the peripheral portion 64, as described above, if the pressing portion 18 presses a wide area of ​​the underside 12b, the overall springiness is reduced. Therefore, as shown by the solid line 75b in FIG. 5, the change in pressure relative to the amount of vibration is small. In other words, the surface pressing structure reduces the responsiveness of the pad 14. In other words, large vibrations, such as external disturbance vibrations, are reduced and absorbed into the pressure within the pad 14. In the embodiment of the present specification, by selectively using a point pressing structure and a surface pressing structure, large disturbance vibrations such as road noise are cancelled by the pressure difference between the pads 12 and 14. This point will be explained below.

[0060] [Pushing section that changes from point pressing to area pressing] 6(a) and 6(b) are cross-sectional views of the module in the first embodiment.

[0061] [Convex pressure point and flexible pad] As shown in Figures 6(a) and 6(b), the pressing portion 16 has a three-dimensional shape in which the cross-sectional area parallel to the upper surface 12a decreases toward the bottom. The pressing portion 16 may have a structure resembling a sliced ​​ball, with the lower surface 14b having a convex shape with an inclined or curved surface. The pressing portion 16 in Figures 8(a) and 8(b) also gradually increases in contact area with the increasing force. This is a mechanism in which the pressing portion 16 penetrates into the pad 12 due to the flexibility of the pad 12, as shown in Figures 6(a) and 6(b). However, the pressing portion 16 may also be flexible, allowing the pressing portion 16 itself to deform and form a surface contact. For example, the pressing portion 16 may be a bag-like member such as a balloon, placed on a flat surface, and pressed from above.

[0062] In addition, as the force applied to the pressing portion 16a in Figures 10, 13(a), 13(b), and 14 increases, the contact area of ​​the pressing portion 16 digitally changes from a small area to a large area. This is also a structure that changes from point pressing to surface pressing. On the other hand, the pressing portion 18 has a wide contact surface and is columnar in shape. The contact area of ​​the pressing portion 18 is large, which corresponds to a surface pressing structure.

[0063] As shown in FIG. 6(a), when the amount of vibration pressing on the upper surface 12a and the lower surface 14b is small, for example, in the case of an S case, the driver's buttocks are positioned at the top, so the pressing portion 16 presses mainly on the center portion 63 of the upper surface 12a. Therefore, as shown by the dashed line 75a in FIG. 5, in the range 61 where the amount of vibration is small, the center 65 is more likely to vibrate, resulting in a large change in pressure in the space 11. On the other hand, because the pressing portion 18 has a surface pressing structure, vital vibrations and other noises are less likely to be transmitted to the pad 14. Therefore, vital vibrations can be detected by detecting the pressure difference with the differential pressure sensor 20.

[0064] When the amount of vibration pressing on the upper surface 12a and the lower surface 14b is large, for example, in the case of an N case, as shown in FIG. 6(b), the pressing portion 16 primarily presses the area from the center 63 to the peripheral edge 64 of the upper surface 12a. This causes the pressing portion 16 to change analogically (continuously) from a point pressing structure to a surface pressing structure. Therefore, in the area 62 of large vibration, as indicated by the dashed line 75a in FIG. 5, both pads 12 and 14 adopt a surface pressing structure, making it difficult for vibration to be transmitted to the pads 12 and 14. This suppresses pressure changes in the spaces 11 and 13 within the pads 12 and 14. This results in the pressure changes in the spaces 11 and 13 becoming equal or approaching each other. In other words, if the vibration is a disturbance vibration, the same amount of disturbance vibration is applied to the two pads 12 and 14, and by calculating the difference, the disturbance vibration can be canceled. Even if complete cancellation is not possible, some degree of cancellation is possible, thereby reducing the output signal of the differential pressure sensor 20 due to the disturbance vibration. In other words, saturation of the preamplifier caused by disturbance vibrations can be suppressed, and vital vibrations superimposed on disturbance vibrations can be detected.

[0065] As described above, the pressing portion 16 is located at the central portion 63 of the upper surface 12a when viewed from the stacking direction (Z direction) of the pads 12 and 14. When the force applied in the -Z direction (toward the upper surface 12a) is small, the area of ​​contact of the pressing portion 16 with the upper surface 12a is small, as shown in FIG. 6(a). As the force increases, the area of ​​contact of the pressing portion 16 with the upper surface 12a increases, as shown in FIG. 6(b). When the force subsequently decreases, the state returns to FIG. 6(a), and the area of ​​contact of the pressing portion 16 with the upper surface 12a decreases. On the other hand, the pressing portion 18 has a surface pressing structure, and contacts at least the central portion of the lower surface 14b of the pad 14. The area of ​​contact between the pressing portion 18 and the lower surface 14b remains almost constant even when the magnitude of the force changes. In other words, the distance between the upper surface 12a of the pad 12 and the lower surface (fifth surface) of the pressing portion 16 decreases from the periphery toward the center. Vibrations can be transmitted between the upper surface 12 a and the lower surface of the pressing portion 16 .

[0066] The center of surface 16d of pressing portion 16 facing upper surface 12a of pad 12 protrudes toward pad 12 beyond peripheral edge 64. Therefore, when no or only a small force is applied to upper surface 12a from pressing portion 16 (point pressing structure), the area of ​​pressing portion 16 in contact with upper surface 12a is preferably 1 / 4 or less, and more preferably 1 / 16 or less, of the planar area of ​​pad 12.

[0067] [Separator: Prevents mutual interference between pads 12 and 14] Next, the separator will be described. Figures 7(a) to 7(c) are cross-sectional views of the module in Example 1. A case will be described in which the upper pressing portion 16 is narrow and the lower pressing portion 18 is wide. The pressing portion 16 has a small contact area, forming a point pressing structure, while the pressing portion 18 has a large contact area, forming a surface pressing structure. In Figure 7(a), the lower surface 12b of pad 12 and the upper surface 14a of pad 14 are in contact. When the two pads 12 and 14 are in contact, the vibrations of pads 12 and 14 interfere with each other, as indicated by arrow 82. With this structure, although detection accuracy is slightly lower than in Figure 7(b), vital vibrations can still be detected.

[0068] On the other hand, Figure 7(b) shows a state in which the two pads 12 and 14 are separated by a separator 50. The separator 50 is located between the lower surface 12b of the pad 12 and the upper surface 14a of the pad 14, and is provided on their peripheral edges. The separator 50 is also provided in contact with the lower surface 12b and the upper surface 14a. Because the peripheral edges of the pads 12 and 14 have low leaf spring properties, vibrations are unlikely to be transmitted between the pads 12 and 14 via the separator 50. Furthermore, the pads 12 and 14 are in contact with each other, suppressing the transmission of vibrations between the pads 12 and 14. Furthermore, the lower surface 12b of the pad 12 and the upper surface 14a of the pad 14 are not in contact with each other but are spaced apart. This further suppresses interference between the vibrations of the pads 12 and 14. Therefore, compared to the structure shown in Figure 7(a), the detection accuracy of vital signs is improved. Separator 50 may be provided in a ring shape around the periphery of lower surface 12b and upper surface 14a, or may be provided independently at the four corners of lower surface 12b and upper surface 14a. If lower surface 12b and upper surface 14a are different in size, separator 50 may be provided around the periphery of at least one of lower surface 12b and upper surface 14a. This separator technical concept applies to all embodiments.

[0069] [Enclosure: Prevents damage to internal components and prevents noise from entering from the sides] As shown in FIG. 7(c), the housing 52 surrounds the pads 12 and 14 with its inner walls. The housing 52 has an upper plate 52a, a lower plate 52b, and a side plate 52c. The shape of the housing 52 varies depending on the planar shapes of the pads 12 and 14. For example, if the planar shapes of the pads 12 and 14 are circular, the shape of the housing 52 is cylindrical, and if the planar shapes of the pads 12 and 14 are polygonal, the shape of the housing 52 is prismatic. The lower surface of the upper plate 52a contacts the pressing portion 16. The upper surface of the lower plate 52b contacts the pressing portion 18. The upper plate 52a and the lower plate 52b are flat.

[0070] The side plate 52c connects the periphery of the upper plate 52a and the periphery of the lower plate 52b to form a box. This housing 52 surrounds the pads 12 and 14 and is located away from the sides or periphery of the pads 12 and 14. A gap 53 composed of air or the like is formed between the side plate 52c and the pads 12 and 14. The side plate 52c may be a ring-shaped plate surrounding the pads 12 and 14, or may be connected by multiple plates extending in the Z direction. For example, if the housing 52 is a hexahedron, the side plate 52c would consist of four plates. Furthermore, the tubes 26 and 27 shown in FIG. 1 extend to the outside through holes provided in the side plate 52c. While the housing 52 has been described as being filled with air, the housing 52 may be filled with a fluid, such as a gas or liquid other than air.

[0071] In this way, the housing 52 surrounds the pads 12 and 14 and connects the pressure elements 16 and 18. This structure prevents damage to the pads 12 and 14, even if excessive human weight is applied to the module 10. Furthermore, because the peripheries of the pads 12 and 14 do not touch the inner wall, vibrations transmitted from the outside of the side panel 52c are also suppressed from penetrating the pads 12 and 14 through the side panel 52c. This is thought to be because the sides of the housing 52 are similar to a surface-pressure structure, making it difficult for large external noise vibrations to propagate. In the S case, the pressure element 16 transmits large vital vibrations to the pad 12, which are then transmitted to the bottom panel 52b via the side panel 52c. These vital vibrations, along with other small noises, penetrate the bottom panel 52b. However, the pressure element 18, which is a surface-pressure element, suppresses the transmission of vibrations to the pad 14. This creates a pressure difference between the pads 12 and 14, allowing the differential pressure sensor 20 to detect vital vibrations. In the N case, disturbance vibrations are transmitted to the upper plate 52a and the lower plate 52b. However, the differential pressure sensor 20 detects the pressure difference between the pads 12 and 14. Therefore, disturbance vibrations are difficult for the differential pressure sensor 20 to detect, and vital vibrations can be detected while suppressing saturation of the output signal due to the preamplifier.

[0072] The housing 52 is made of a material harder than the pads 12 and 14, and is primarily made of, for example, a hard resin such as acrylic or metal. The lower plate 52b and the side plate 52c may be integrally molded, excluding the upper plate 52a. The upper plate 52a may be a lid with a gasket. The upper plate 52a, the lower plate 52b, and the side plate 52c may be separate members joined together with a bonding agent or the like. The upper plate 52a and the pressing portion 16 may be integrally formed, or may be separate members joined together with a bonding agent or the like. The lower plate 52b and the pressing portion 18 may be integrally formed, or may be separate members joined together with a bonding agent or the like. The pressing portions 16 and 18 may correspond to the first pressing portion and the second pressing portion, respectively, and the housing 52 may correspond to the support member. The pressing portion 16 and the upper plate 52a may correspond to a first pressing portion, the pressing portion 18 and the lower plate 52b may correspond to a second pressing portion, and the side plate 52c may correspond to a support member. Here, the separator 50 and the housing 52 have been described, but the technical concept of the separator 50 or the housing 52 can be adopted in all embodiments.

[0073] [Axis member 54 and plate-like member 55] 8(a) and 9(b) are diagrams illustrating another example of the first embodiment. As shown in FIG. 8(a), the plate-shaped member 55 is provided on the opposite side of the upper plate 52a from the pad 12, spaced apart from the upper plate 52a. The shaft member 54 connects the center of the plate-shaped member 55 to the center of the upper plate 52a. The area of ​​the shaft member 54 cut in a planar direction (hereinafter referred to as the planar area) is smaller than the planar area of ​​the plate-shaped member 55. The weight of the human body 60 is applied to the plate-shaped member 55. A cushioning material may be provided between the plate-shaped member 55 and the human body 60. The shaft member 54 transmits vibrations of the human body 60 to the center of the upper plate 52a. The vital vibration source of the human body 60 is a small area. Even if the seating position of the human body 60 shifts in the X and Y directions, vital vibrations from the vital vibration source are transmitted from the plate-shaped member 55 to the upper plate 52a via the shaft member 54. This is similar to the working principle of a scale: even if the object being measured is off-center, the weight remains the same.

[0074] The term "axis" literally means an axis located at the center, and in this case refers to an axis located approximately at the center of plate-like member 55, which serves as the upper tray. Even if the position of the buttocks or the position of the blood vessels of the human body deviates from the center of plate-like member 55, the vital vibrations propagate through plate-like member 55 and are transmitted to the center of upper plate 52a, which is the vibrating plate, via axis member 54. Therefore, even if the vital vibration source is slightly deviated from the center of plate-like member 55, the vital vibrations are transmitted to pad 12.

[0075] The central portion of upper plate 52a has high leaf spring properties, so vibrations are transmitted from pressing portion 16 to pad 12. In order to transmit vital signals to pad 12 even if the seating position of human body 60 shifts, the planar area of ​​shaft member 54 is preferably 1 / 4 or less, and more preferably 1 / 10 or less, of the planar shape of plate-shaped member 55. Plate-shaped member 55, shaft member 54, and upper plate 52a may be formed integrally, or may be separate members joined by adhesive or the like.

[0076] [Convex pressing part 16] The top surface 12a of the pad 12 is flat, and the downward surface 16d of the pressing portion 16, which faces the top surface 12a of the pad 12, is curved so that the center protrudes below the periphery. When no vibration is applied to the pad 12, the area of ​​the pressing portion 16 in contact with the top surface 12a is small. As the vibration increases, the pressing portion 16 sinks into the pad 12, increasing the area of ​​contact with the top surface 12a. When the vibration then decreases, the pressing portion 16 returns to its original state, and the area of ​​contact with the top surface 12a of the pressing portion 16 decreases.

[0077] In the case of an S case with no disturbance vibration, vital vibrations transmitted to the pressing portion 16 via the shaft core member 54 cause the pressing portion 16 to press the surface of the pad 12 in a point-pressing structure. As a result, the center of the upper surface 12a of the pad 12 vibrates greatly up and down. On the other hand, the lower plate 52b has a surface-pressing structure of the pressing portion 18, so the propagation of vibrations to the pad 14 is suppressed. Furthermore, the differential pressure sensor 20 detects the pressure difference between the pad 12 and the pad 14, and therefore can detect vital vibrations.

[0078] On the other hand, in the case of the N-type case, large vibrations such as disturbance vibrations penetrate through the lower plate 52b. The side plate 52c of the housing 52 deforms slightly outward, causing the upper plate 52a to press the pressing portion 16, which then sinks into the pad 12. This changes the pressing portion 16 to a surface pressing structure. The disturbance vibrations also flow around the plate-like member 55, flattening the pressing portion 16. Furthermore, the pressing portion 18 of the pad 14 has a surface pressing structure from the beginning. Therefore, large forces such as disturbance vibrations are transmitted to the pads 12 and 14. The differential pressure sensor 20 detects the pressure difference between the pads 12 and 14, which can cancel out the vibrations transmitted to the pads 12 and 14 to some extent. This reduces the output signal of the differential pressure sensor 20 due to disturbance vibrations, thereby suppressing preamplifier saturation. This improves the detection accuracy of vital vibrations superimposed on disturbance vibrations.

[0079] As shown in FIG. 8(b), a separator 50 is provided on the periphery between the pads 12 and 14. By providing the separator 50, it is possible to suppress interference of vibrations between the pads 12 and 14, and further improve detection accuracy. The other configurations are the same as those in FIG. 8(a), and therefore a description thereof will be omitted. Note that in FIGS. 8(a) and 8(b), the pressing portion 16 may be in contact with the lower plate 52b, and the pressing portion 18 may be in contact with the upper plate 52a. In other words, the configurations of the pressing portions 16, 18, pads 12, 14, and separator 50 may be upside down.

[0080] 9(a) and 9(b), pads 14 and 12 correspond to the first and second members, respectively. The lower surface 14b and upper surface 14a of pad 14 correspond to the first and second surfaces, respectively, which face each other. The lower surface 12b and upper surface 12a of pad 12 correspond to the third and fourth surfaces, respectively, which face each other. The lower plate 52b corresponds to the first pressing portion. The pressing portion 16 and upper plate 52a correspond to the second pressing portion.

[0081] [Curved Pad 14] As shown in FIG. 9(a), the pressing portion 16 is wide and is provided from the center to the periphery of the upper surface 12a of the pad 12. In other words, the pressing portion 16 has a surface pressing structure. The center of the lower surface 14b of the pad 14 protrudes further toward the lower plate 52b than the periphery. In other words, the pressing portion 18 has a point pressing structure. In this way, the inner surface of the lower plate 52b is flat, and the lower surface 14b of the pad 14 protrudes. With this structure, the pad 12 side has a surface pressing structure, and the pad 14 has a point pressing structure. In FIGS. 6(a) and 6(b), the pressing portion 16 has changed from a point pressing to a surface pressing, but in FIG. 9(a), the center of the pad 14 is in contact with the lower plate 52b, changing from a point pressing to a surface pressing structure.

[0082] Therefore, in a situation where there is no external vibration, such as in the S case, vital vibration is transmitted to the pad 14 via the plate-like member 55, the shaft member 54, the upper plate 52a, the pressing portion 16, and the peripheral edge (side wall) of the pad 12. Because the lower plate 52b has a point pressing structure, even small vibrations such as vital vibrations are transmitted to the pad 14 side. (In Figure 9(b) , the separator also acts as an intermediary.) Therefore, the lower pad 14 vibrates greatly, while the vibration of the upper pad 12 is suppressed. Ultimately, vital vibrations can be detected by detecting the pressure difference between the pads 12 and 14.

[0083] On the other hand, in the case of the N case, when a large vibration such as a disturbance vibration is applied, the lower plate 52b and the pad 14 form a surface pressing structure, and the upper plate 52a, the pressing portion 16, and the pad 12 also form a surface pressing structure. As a result, the propagation of the disturbance vibration to the pads 12 and 14 is suppressed. Furthermore, when the pressure difference between the pads 12 and 14 is detected by the differential pressure sensor 20, the output signal due to the disturbance vibration becomes smaller, and the detection accuracy of the vital vibration can be improved.

[0084] As shown in FIG. 9(b), a separator 50 is provided on the periphery between the pads 12 and 14. By providing the separator 50, vibration interference between the pads 12 and 14 can be suppressed. The principle and effect of the separator 50 are as described above. The other configurations are the same as those in FIG. 9(a), and therefore description thereof will be omitted. Note that in FIG. 9(a), the upper surface 12a of the pad 12 protrudes toward the upper plate 52a, and the lower surface 14b of the pad 14 is flat. A pressing portion 18 having a structure similar to the pressing portion 16 in FIG. 9(a) may be provided between the pad 14 and the lower plate 52b, or the separator 50 may be provided as shown in FIG. 9(b). In other words, the configurations of the pressing portions 16, 18, pads 12, 14, and separator 50 may be upside down.

[0085] The elastic modulus of the material used for the pads 12 and 14 is preferably 2 MPa to 5000 MPa. For example, the material for the pads 12 and 14 is polyethylene resin (elastic modulus: 1080 MPa). The elastic modulus of the material used for the pressing portions 16 and 18, the separator 50, the housing 52, the shaft member 54, and the plate-like member 56 is preferably greater than the elastic modulus of the material used for the pads 12 and 14, for example, preferably 2 MPa to 10000 MPa. The same applies to the following examples. For example, the material for the pressing portions 16 and 18, the separator 50, the housing 52, the shaft member 54, and the plate-like member 56 is acrylic resin (3000 MPa). [Example]

[0086] [Structure with pressing portions 16a and 16b] FIG. 10 is a cross-sectional view of a module according to a second embodiment. FIGS. 11(a) to 11(d) are plan views of the module according to the second embodiment. FIG. 11(a) illustrates a plate-like member 55 and a shaft member 54. FIG. 11(b) illustrates a pad 12, pressing portions 16a and 16b, and a side plate 52c. FIG. 11(c) illustrates pads 12 and 14, a separator 50, and a side plate 52c. FIG. 11(d) illustrates a pad 14, pressing portion 18, and a lower plate 52b. In the second embodiment, the pads 12 and 14 correspond to the first and second members, respectively. The upper surface 12a and the lower surface 12b of the pad 12 correspond to the first and second surfaces, respectively, which face each other. The upper surface 14a and the lower surface 14b of the pad 14 correspond to the third and fourth surfaces, respectively, which face each other. The upper plate 52a corresponds to the third member. The pressing portions 16a and 16b correspond to the first pressing portion and the second pressing portion, respectively. The pressing portion 18 and the lower plate 52b correspond to the third pressing portion. The side plate 52c corresponds to the support member.

[0087] As shown in Figures 10 to 11(d), two pressing portions 16a and 16b are provided between the upper plate 52a and the pad 12. The pressing portion 16a is located at the center of the upper surface 12a of the pad 12. The pressing portion 16a is in contact with and fixed to the upper plate 52a. When no force or a small force is applied from the pressing portion 16a toward the pad 12 (in the case of the S case), the pressing portion 16a and the upper surface 12a are not in contact. When the force increases, as in the case of the N case, the pressing portion 16a and the pressing portion 16b come into contact with the upper surface 12a at some point. When the force decreases, the pressing portion 16a and the upper surface 12a separate and return to their original positions. The pressing portion 16b is located on the periphery of the upper surface 12a between the upper surface 12a and the upper plate 52a, and is always in contact with the upper surface 12a and the upper plate 52a regardless of the magnitude of the force. The pressing portions 16b are provided at the four corners of the pad 12. The pressing portions 16b may be ring-shaped or may be provided on a pair of opposing sides of the upper surface 12a, provided that they are provided on the peripheral edge of the upper surface 12a. Separators 50 are provided on the four corners of the lower surface 12b of the pad 12 and the upper surface 12a of the pad 14. The separators 50 may be ring-shaped or may be provided along two opposing sides of the upper surface 12a, provided that they are provided on the peripheral edge of the lower surface 12b and the upper surface 14a. The other configurations are the same as those in FIG. 8(b) of Example 1, and therefore description thereof will be omitted.

[0088] The operation of the module of Example 2 will be described. First, we will describe the case of the S case, where no external vibrations are applied to the module 10 and vital vibrations are applied to the module 10 from the human body 60. If we consider the separator 50 as a fixed end, the vital vibrations are transmitted to the plate-shaped member 55, the axial member 54, and the upper plate 52a. The axial member 54 abuts the center of the upper plate 52a. The axial member 54 forms a point-pressing structure, and the vital vibrations are transmitted to the upper plate 52a. The pressing portion 16b is provided on the peripheral edge of the upper surface 12a of the pad 12. Therefore, the pressing portion 16b has a surface-pressing structure. Therefore, vibrations of the pad 12 are suppressed, and vibrations transmitted from the upper plate 52a to the pressing portion 16b are not easily transmitted to the pad 12. Because the pressing portion 16a is not in contact with the pad 12, the vital vibrations are not easily transmitted to the pad 12 even via the pressing portion 16a. Vital vibrations are transmitted from upper plate 52a to pad 14 via side plate 52c, lower plate 52b, and pressing portion 18. The contact area of ​​pressing portion 18 on the pad 14 side is smaller than the contact area of ​​pressing portion 16b on the pad 12 side, resulting in a difference in the vital vibrations transmitted to pad 12 and pad 14. Therefore, when differential pressure sensor 20 detects the pressure difference between pads 12 and 14, vital vibrations can be detected, although the difference will be slightly smaller.

[0089] Next, we will explain the case where a disturbance vibration, such as a disturbance vibration, is applied to the module 10 in the N case. When this large vibration is applied to the plate-like member 55, the disturbance vibration transmitted from the plate-like member 55 causes the upper plate 52a to deform downward into a convex shape. As a result, both of the pressing portions 16a and 16b contact the upper surface 12a. Note that the pressing portion 16b may also deform flat. Therefore, the disturbance vibration transmitted to the housing 52 transforms the pressing portions 16a and 16b and the pad 12 into a surface-pressing structure. Furthermore, a large disturbance vibration applied from below is transmitted from the pressing portion 16a, which has a surface-pressing structure, to the pad 12, and then from the pressing portion 18 to the pad 14. By setting the total contact area of ​​the pressing portions 16a and 16b and the contact area of ​​the pressing portion 18 to be roughly the same, the pressure changes on the pads 12 and 14 can be made to be approximately the same. As a result, disturbance vibrations are canceled to some extent by the differential pressure sensor 20, and the output signal of the differential pressure sensor 20 can be reduced. Therefore, saturation of the preamplifier is suppressed, and vital vibrations superimposed on disturbance vibrations can be detected. Note that in FIG. 10, a pressing portion 16 having the same shape as pressing portion 18 in FIG. 10 may be provided between the pad 12 and the upper plate 52a, a pressing portion having the same shape as pressing portion 16a in FIG. 10 may be in contact with the lower plate 52b and spaced apart from the pad 14, and a pressing portion having the same shape as pressing portion 16b in FIG. 10 may be in contact with the lower plate 52b and the pad 14. In other words, the configurations of pressing portions 16a, 16b, 18, pads 12, 14, and separator 50 may be arranged upside down.

[0090] [Experiment 1] The module of Example 2 was used to detect changes in pressure in spaces 11 and 13 due to vital vibrations and external vibrations. Pads 12 and 14 were made of polyethylene. The other components were made by cutting acrylic plates. Instant adhesive was applied to the cut components to a thickness of 0.1 mm, and then the components were joined together.

[0091] The dimensions of each component are as follows: Plate-shaped member 55: X×Y×Z=55mm×55mm×2mm Axis core member 54: X×Y×Z=15mm×15mm×1mm Upper plate 52a: X×Y×Z=55mm×55mm×1mm Lower plate 52b:X×Y×Z=55mm×55mm×3mm Side panel 52c: X, Y = 55 mm (width) x 5 mm (thickness), Z = 21.6 mm Holes (X, Y x Z = 8 mm x 15 mm) for the tubes 26 and 27 are formed on one surface of the side plate 52c. The upper plate 52a, the lower plate 52b and the side plate 52c were bonded together using an adhesive with a thickness of 0.1 mm. Push part 16a: X×Y×Z=15mm×15mm×1mm Push part 16b:X×Y×Z=5mm×5mm×2mm Push part 18: X×Y×Z=25mm×25mm×1mm Separator 50: X×Y×Z=5mm×5mm×2mm Pads 12 and 14: X x Y x Z = 40 mm x 40 mm x 8 mm, thickness is 1 mm

[0092] The urethane material used for the seat was prepared and cut into a cushion shape measuring X x Y x Z = 300 mm x 300 mm x 60 mm. A countersunk hole was created in the center of the cushion, and the module 10 was placed inside the hole. A lid made of the same urethane material as the cushion was placed over the countersunk hole. A weak vibration equivalent to a vital sign was applied to the lid by lightly pressing the top surface of the lid with a finger. A strong vibration equivalent to a disturbance vibration was applied to the lid by hitting the lid hard with a hand. The pressure in spaces 11 and 13 between pads 12 and 14 was then detected by a detector.

[0093] FIG. 12 shows the detector output signal versus time in Experiment 1. In FIG. 12, period 70 is the period during which vibrations corresponding to vital signals were applied, and period 71 is the period during which vibrations corresponding to disturbance vibrations were applied. As shown in FIG. 12, during period 70, the output signal from pad 14 is larger than the output signal from pad 12. This suggests that vital vibrations can be detected even if pressure changes at pads 12 and 14 are canceled using differential pressure sensor 20. During period 71, the output signals from pads 12 and 14 are approximately the same magnitude. This suggests that disturbance vibrations can be canceled by canceling pressure changes at pads 12 and 14 using differential pressure sensor 20. This point is explained below.

[0094] According to the second embodiment, the pressing portion 16a is located between the upper surface 12a and the upper plate 52a (third member) and is located at the center of the upper surface 12a. When no force or a small force is applied from the upper plate 52a toward the pad 12, i.e., in the S case, the pressing portion 16a does not contact the pad 12. However, in the N case, when the force increases, the pressing portion 16a contacts the pad 12. The pressing portion 16b (third pressing portion) is located between the upper surface 12a and the upper plate 52a, at the periphery of the upper surface 12a, and contacts the upper surface 12a and the upper plate 52a. Vibrations can be transmitted between the upper surface 12a and the upper plate 52a via the pressing portion 16a. The pressing portion 18 contacts at least the center of the lower surface 14b. In other words, the pads 12 and 14 each have a surface pressing structure, and external vibrations such as road noise are transmitted to the pads 12 and 14 at reduced intensity. As a result, the disturbance vibration is canceled to some extent in the differential pressure sensor 20, the output signal of the differential pressure sensor 20 becomes smaller, and it becomes possible to detect vital vibration superimposed on the disturbance vibration.

[0095] [Modification 1 of Example 2] Fig. 13(a) is a cross-sectional view of a module in Modification 1 of Example 2. As shown in Fig. 13(a), in the S case, when no force such as vital vibration is applied to the module or when the force is small, the pressing portion 16a is not in contact with the upper plate 52a. In the N case, when the force increases, the upper plate 52a deforms and the pressing portion 16a comes into contact with the upper plate 52a. When the force decreases again, the pressing portion 16a separates from the upper plate 52a and returns to its original position.

[0096] In the S case, when small vibrations such as vital vibrations are applied to the module, even if the vital vibrations are transmitted to the upper plate 52a via the shaft core member 54, the center of the pad 12 does not abut against the upper plate 52a. The vibrations are not transmitted much from the pressing portion 16b to the pad. Instead, the vibrations are transmitted mainly to the pad 14 via the side plate 52c, the lower plate 52b, and the pressing portion 18. This creates a pressure difference between the pads 12 and 14, allowing the vital vibrations to be detected by the differential pressure sensor 20.

[0097] In the N case, when a large disturbance vibration such as road noise is applied to the module, the upper plate 52a deforms and the pressing portion 16a comes into contact with the upper plate 52a. In other words, the pressing portion 16a has a surface pressing structure. And because both the pad 14 and the pressing portion 18 have a surface pressing structure, the disturbance vibration is suppressed and transmitted to the pads 12 and 14. If the pressure difference between the pads 12 and 14 is detected, the disturbance vibration signal is canceled to some extent by the differential pressure sensor 20. As a result, the output signal of the differential pressure sensor 20 becomes smaller and the output of the preamplifier becomes non-saturated. Therefore, vital vibration superimposed on the disturbance vibration can be detected. Note that the other configurations are the same as those of the second embodiment, and therefore a description thereof will be omitted.

[0098] Next, in the reverse relationship to Example 2 and its Modification 1, the pressing portion 16a may be in contact with the upper plate 52a and spaced apart from the pad 12. Note that a pressing portion 16 having the same shape as the pressing portion 18 in FIG. 13(a) may be provided between the pad 12 and the upper plate 52a, a pressing portion having the same shape as the pressing portion 16a in FIG. 13(a) may be in contact with the pad 14 and spaced apart from the lower plate 52b, and a pressing portion having the same shape as the pressing portion 16b may be in contact with the pad 14 and the lower plate 52b. In other words, the configurations of the pressing portions 16a, 16b, 18, the pads 12 and 14, and the separator 50 may be arranged upside down.

[0099] [Modification 2 of Example 2] FIG. 13(b) is a cross-sectional view of a module in Modification 2 of Example 2. As shown in FIG. 13(b), in the S case, when no force is applied from the upper plate 52a toward the pad 12 or when the force is small, the area where the pressing portion 16a contacts the upper surface 12a of the pad 12 is small or is spaced apart, and the pressing portion 16a has a point pressing structure. In the N case, when the force increases, the area where the pressing portion 16a contacts the upper surface 12a increases. The pressing portion 16a has a surface pressing structure. Furthermore, when the force decreases, the area where the pressing portion 16a contacts the upper surface 12a decreases and returns to its original state. In FIG. 13(b), in the S case, vital vibrations are transmitted mainly to the pad 14, and in the N case, disturbance vibrations are transmitted to both the pads 12 and 14.

[0100] In the S case, vital vibrations are transmitted to the plate-shaped member 55, the axial member 54, and the upper plate 52a. The axial member 54 abuts the center of the upper plate 52a, forming a point-pressure structure, and vital vibrations are transmitted to the upper plate 52a. The pressing portion 16b contacts the peripheral edge of the pad 12 and the housing 52, while the pressing portion 16a is not in contact with the pad 12 or is in weak contact with it. Vital vibrations are not transmitted very much from the pressing portion 16b to the pad 12. Vital vibrations are transmitted to the pad 14 via the side plate 52c, the lower plate 52b, and the pressing portion 18. This creates a pressure difference between the two pads 12 and 14, and when the differential pressure sensor 20 detects the pressure difference, vital vibrations are detected.

[0101] On the other hand, in the N case, when disturbance vibration is applied to the module, the lower part of the pressing part 16a comes into contact with the pad 12 or makes strong contact with it. This causes the contact area between the two pads 12 and the pressing part 16a and the contact area between the pads 14 and 18 to become closer. Both the pressing parts 16a and 18 have a surface pressing structure. This suppresses the vibration transmitted to the pads 12 and 14. By detecting the pressure difference between the two pads 12 and 14 with the differential pressure sensor 20, the output signal of the differential pressure sensor 20, which corresponds to the disturbance vibration, can be further reduced. This makes it possible to detect vital vibrations superimposed on the disturbance vibration. 13(b), a pressing portion 16 having the same shape as pressing portion 18 in Fig. 13(b) may be provided between pad 12 and upper plate 52a, a pressing portion having the same shape as pressing portion 16a in Fig. 13(b) may be in contact with lower plate 52b, and a pressing portion having the same shape as pressing portion 16b in Fig. 13(b) may be in contact with pad 14 and lower plate 52b. In other words, the configurations of pressing portions 16a, 16b, 18, pads 12, 14, and separator 50 may be arranged upside down.

[0102] [Modification 3 of Example 2] [Structure in which the lower plate 52b of the housing is omitted] Fig. 14 is a cross-sectional view of a module in Modification 3 of Example 2. As shown in Fig. 14, housing 52 does not have lower plate 52b, and lower plate 52d is provided outward from the lower end of side plate 52c. In Modification 3 of Example 2, since lower plate 52b is not provided, pressing portion 18 is not supported by housing 52. Since the module is embedded in a recess in the seat cushion, pressing portion 18 is supported by seat cushion 44 (see Fig. 3) made of urethane or the like, which serves as the bottom portion.

[0103] The entire area below the plate-like member 55 is embedded in the seat, as shown in Figures 3, 22(a) and 22(b). A recess is formed in the seat to accommodate the module, and the module is mounted in the recess. A seat cover is provided on top of the seat, including the recess. The driver and passengers sit on the seat. This configuration may be applied to all embodiments.

[0104] In the S case, vital vibrations of the occupant are mainly transmitted to the upper plate 52a via the plate-shaped member 55 and the shaft member 54. The pressing portion 16a abuts and is fixed to the pad 12, but the upper surface of the pressing portion 16a is spaced apart from the upper plate 52a. On the other hand, the pressing portion 16b abuts against the four corners of the pad 12 or abuts in a ring-like manner. Therefore, the pressing portions 16a and 16b form a surface pressing structure in the pad 12, which suppresses the transmission of vital vibrations to the pad 12. The vital vibrations are transmitted downward to the side plate 52c. The pressing portion 18 is supported by the recess in the seat, i.e., the bottom surface of the foam resin. Therefore, the vital vibrations are transmitted from the side plate 52c via the foam resin to the pressing portion 18, and the pressing portion 18 presses the pad 14. In this way, the vital vibrations transmitted to pad 12 are suppressed, and because pressing portion 18 abuts on the center of lower surface 14b, the vital vibrations are transmitted to pad 14. This causes a pressure difference between two pads 12 and 14, and the vital vibrations can be detected by differential pressure sensor 20.

[0105] On the other hand, in the N-case, disturbance vibrations are applied to the module from both above and below. Because the vibrations are large, pressing portion 16a contacts upper plate 52a, and pressing portion 16b, which presses against the peripheral edge, and pressing portion 16a form a surface pressing structure. Furthermore, pressing portion 18, supported on the bottom surface of the foamed resin, also forms a surface pressing structure. Because the contact areas between two pads 12 and pressing portions 16a and 16b and between pad 14 and pressing portion 18 are close to each other, vibrations entering both pads 12 and 14 are suppressed. The pressure difference between pads 12 and 14 is reduced. The output signal from differential pressure sensor 20 is reduced, and the output signal from the preamplifier is not saturated. Vital vibrations are superimposed on the disturbance vibrations, and these vital vibrations can be detected as vital signals using the signal processing shown in Figure 2. It is preferable to provide plate-like member 55 and shaft member 54 to transmit vital vibrations from the human body to upper plate 52a. 14 may be provided between the pad 12 and the upper plate 52a, and pressing portions having the same shapes as the pressing portions 16a and 16b in FIG. 14 may be provided in contact with the lower surface 14b below. In other words, the configurations of the pressing portions 16a, 16b, 18, the pads 12, 14, and the separator 50 may be arranged upside down. [Example]

[0106] FIG. 15 is a cross-sectional view of a module according to a third embodiment. FIGS. 16(a) to 16(d) are plan views of the module according to the third embodiment. FIG. 16(a) illustrates an upper plate 52a and a plate-like member 56. FIG. 16(b) illustrates a pad 12, pressing portions 16a and 16b, and a side plate 52c. FIG. 16(c) illustrates a pad 12, 14, and a side plate 52c. FIG. 16(d) illustrates a pad 14, pressing portion 18, and a lower plate 52b. In the third embodiment, the pads 12 and 14 correspond to the first and second members, respectively. The upper surface 12a and the lower surface 12b of the pad 12 correspond to the first and second surfaces, respectively, which face each other. The upper surface 14a and the lower surface 14b of the pad 14 correspond to the third and fourth surfaces, respectively, which face each other. The pressing portion 16a and the plate-like member 56 correspond to the first pressing portion. The pressing portion 18 and the lower plate 52b correspond to the second pressing portion. The pressing portion 16b and the upper plate 52a correspond to the second pressing portion. The side plate 52c corresponding to the third pressing portion corresponds to the support member.

[0107] As shown in Figures 15 to 16(d), the plate-shaped member 55 and the shaft member 54 are not provided. An opening 57 is provided in the center of the upper plate 52a. A plate-shaped member 56 is provided within the opening 57. The periphery of the upper plate 52a and the plate-shaped member 56 are spaced apart. A pressing portion 16a is provided between the plate-shaped member 56 and the pad 12. Regardless of the force applied from the pressing portion 16a toward the pad 12, the pressing portion 16a and the upper surface 12a are in contact, and the pressing portion 16a and the plate-shaped member 56 are also in contact. The pressing portion 16b is located on the periphery of the upper surface 12a between the upper surface 12a and the upper plate 52a, is in contact with the upper surface 12a and the upper plate 52a, and is spaced apart from the pressing portion 16a. The pressing portions 16b are provided at the four corners of the pad 12. As long as the pressing portions 16b are provided on the periphery of the upper surface 12a, they may be provided at each of the four corners or in a ring shape. They may also be provided on a pair of opposing sides of the upper surface 12a. The lower surface 12b of the pad 12 and the upper surface 14a of the pad 14 are in contact with each other. The pressing portion 18 is provided between the pad 14 and the lower plate 52b and is in contact with the pad 14 and the lower plate 52b. The other configurations are the same as those in the second embodiment, and therefore a description thereof will be omitted.

[0108] The operation of the module of Example 3 will be described. First, a case where vital vibrations are transmitted from the human body 60 to the module 10 in the S case will be described. Because the pressing portion 16b holds the peripheral edge of the pad 12, it appears that the propagation of vibrations to the pad 12 is suppressed. However, in reality, the plate-like member 56 is independent of the upper plate 52a, so the pressing portions 16a and 16b move separately. Vital vibrations are transmitted from the plate-like member 56 and the pressing portion 16a to the center of the upper surface 12a of the pad 12. The pressing portion 16a has a point pressing structure. Because the center of the upper surface 12a has high leaf spring properties, the pressure in the space 11 changes sensitively due to vital vibrations. Because the pressing portion 16b contacts the peripheral edge of the pad 12, vibrations are not easily transmitted from the pressing portion 16b to the pad 12.

[0109] On the other hand, when pad 12 is pressed, pad 14 is pressed by pressing portion 18, but pressing portion 18 contacts peripheral edge 64 from the center of undersurface 14b, suppressing the responsiveness of pad 14 and preventing sensitive changes in pressure within space 13. Therefore, a pressure difference occurs between pads 12 and 14, allowing vital vibrations to be detected by differential pressure sensor 20.

[0110] Next, we will explain the case where disturbance vibration is transmitted to module 10 in the N case. When a large disturbance vibration is applied to the module, this disturbance vibration propagates from below to lower plate 52b, and pressing portion 18 presses pad 14 in a surface pressing structure. Meanwhile, on upper plate 52a, disturbance vibration is applied from side plate 52c and the periphery of the sheet. Pressing portions 16a and 16b form a surface pressing structure. Therefore, the propagation of disturbance vibration to pads 12 and 14 is suppressed. The pressure difference between pads 12 and 14 is small, and the output signal of differential pressure sensor 20 is small. Therefore, the output signal of the preamplifier does not saturate, and vital vibration superimposed on the disturbance vibration can be detected.

[0111] [Experiment 2] The module of Example 3 was used to detect changes in pressure in spaces 11 and 13 due to vital vibrations and external vibrations. Pads 12 and 14 were made of polyethylene. The other components were made by cutting acrylic plates. Instant adhesive was applied to the cut components to a thickness of 0.1 mm, and then the components were joined together.

[0112] The dimensions of each component are as follows: Plate member 56: Diameter φ=25mm, Z=3mm Upper plate 52a: X×Y×Z=55mm×55mm×3mm Opening 57: Diameter φ=30mm Lower plate 52b:X×Y×Z=55mm×55mm×3mm Side panel 52c: X, Y = 55 mm (width) x 5 mm (thickness), Z = 19.5 mm Holes (X, Y x Z = 8 mm x 15 mm) for the tubes 26 and 27 are formed on one surface of the side plate 52c. The upper plate 52a, the lower plate 52b and the side plate 52c were bonded together using an adhesive with a thickness of 0.1 mm. Push part 16a: Diameter φ=15mm, Z=2mm Push part 16b:X×Y×Z=5mm×5mm×2mm Push part 18: X×Y×Z=25mm×25mm×1mm Pads 12 and 14: X x Y x Z = 40 mm x 40 mm x 8 mm, thickness is 1 mm

[0113] A countersunk hole was created in the center of a cushion made of urethane, measuring X x Y x Z = 300 mm x 300 mm x 60 mm, and the module 10 was placed inside the hole. The countersunk hole was covered with a urethane lid made of the same material as the cushion. As a vital vibration, a weak vibration equivalent to a vital signal was applied to the lid by lightly pressing the top surface of the lid with a finger. As a disturbance vibration, a strong vibration equivalent to a disturbance vibration was applied to the lid by hitting the lid hard with a hand. The pressure in spaces 11 and 13 between pads 12 and 14 was detected by a detector.

[0114] Figure 17 shows the results of Experiment 2, illustrating the detector output signal over time. As shown in Figure 17, during period 70, which corresponds to the S case and in which small vibrations such as vital signs occur, the output signal from pad 12 is larger than the output signal from pad 14. This suggests that vital signs can be detected even when pressure changes at pads 12 and 14 are canceled using differential pressure sensor 20. During period 71, although there is a difference between the output signals from pads 12 and 14, they are roughly the same magnitude across the entire range. Therefore, when pressure changes at pads 12 and 14 are detected using differential pressure sensor 20, the pressure at pads 12 and 14 is canceled to some extent, reducing the output signal corresponding to the disturbance vibration. Therefore, vital signs superimposed on these disturbance vibrations can be detected.

[0115] According to the third embodiment, the pressing portion 16a contacts the center of the upper surface 12a of the pad 12. The pressing portion 18 contacts at least the center of the lower surface 14b of the pad 14, and the area where the pressing portion 18 contacts the lower surface 14b is larger than the area where the pressing portion 16a contacts the upper surface 12a. This allows vital vibrations to be transmitted mainly to the pad 12. The area where the pressing portion 18 contacts the lower surface 14b is preferably at least twice the area where the pressing portion 16a contacts the upper surface 12a, and more preferably at least four times the area where the pressing portion 16a contacts the upper surface 12a. The area where the pressing portion 16a contacts the upper surface 12a is preferably 1 / 3 or less of the planar area of ​​the pad 12, and more preferably within the range of 1 / 32 to 1 / 8. The pressing portion 16a and the plate-like member 56, and the pressing portion 16b and the upper plate 52a move independently of each other.

[0116] Furthermore, the lower surface 12b of the pad 12 is in contact with the upper surface 14a of the pad 14. This makes it easier for the vibration to be transmitted to both the pads 12 and 14 when disturbance vibration is applied to the module.

[0117] The upper surface of the upper plate 52a and the upper surface of the plate-shaped member 56 may be located on the same plane. The upper surface of the plate-shaped member 56 is preferably located above the upper surface of the upper plate 52a, but may also be located below. The plate-shaped member 56 and the pressing portion 16a may be molded integrally, or may be formed separately and joined with an adhesive or the like. The upper plate 52a and the pressing portion 16b may be molded integrally, or may be formed separately and joined with an adhesive or the like. Note that the upper plate 52a, the plate-shaped member 56, the pressing portions 16a, and 16b may be located on the lower surface 14b of the pad 14, and the lower plate 52b and the pressing portion 18 may be located on the upper surface 12a of the pad 12. In other words, the configuration of the pressing portions 16a, 16b, and 18, the pads 12 and 14, the separator 50, the upper plate 52a, the plate-shaped member 56, and the lower plate 52b may be arranged upside down. [Example]

[0118] [One-pad structure: The housing suppresses external vibrations] FIG. 18(a) is a cross-sectional view of a module according to a fourth embodiment, and FIGS. 18(b) and 18(c) are plan views of the module according to the fourth embodiment. FIG. 18(b) illustrates an upper plate 52a and a pressing portion 16. FIG. 18(c) illustrates a pad 12, a pressing portion 16, and a side plate 52c. In the fourth embodiment, the pad 12 corresponds to a member. The upper surface 12a and the lower surface 12b of the pad 12 correspond to a first surface and a second surface facing each other, respectively. The pressing portion 16 and the lower plate 52b correspond to a first pressing portion and a second pressing portion, respectively. The side plate 52c and the upper plate 52a correspond to a housing.

[0119] As shown in Figures 18(a) to 18(c), one pad 12 is provided. The pressing portion 16 is in contact with the center of the upper surface 12a of the pad 12. An opening 57 is provided in the center of the upper plate 52a. The pressing portion 16 passes through the opening 57 and is in contact with or fixed to the center of the plate-like member 55. The lower surface 12b of the pad 12 is in contact with the lower plate 52b. The side plate 52c connects the periphery of the upper plate 52a and the periphery of the lower plate 52b, surrounds the pad 12, and is separated from the pad 12. The space 11 within the pad 12 is connected to the sensor 20a via the tube 26. The sensor 20a detects the pressure in the space 11. The other configurations are the same as those of Example 1, so description thereof will be omitted.

[0120] In the fourth embodiment, the pressing portion 16 is in contact with the center of the upper surface 12a of the pad 12. As a result, when vital vibrations are transmitted from the pressing portion 16 to the pad 12, the sensor 20a can detect the vital vibrations with high accuracy. The housing 52 is preferably a rigid body. The housing 52 is generally a hexahedron, with each surface supporting each peripheral edge. This creates a mutual surface pressing structure, and the combined effect of these two components can suppress the penetration of disturbance vibrations such as road noise into the pad 12. Therefore, whether the vital vibrations are mostly present in the S case or when disturbance vibrations are added to the vital vibrations in the N case, the propagation of disturbance vibrations to the pad 12 can be significantly suppressed. This allows the vital vibrations to be detected.

[0121] The area of ​​the pressing portion 16 in contact with the upper surface 12a is preferably 1 / 4 or less, and more preferably 1 / 16 or less, of the planar area of ​​the pad 12. Since the housing 52 surrounds the pad 12, external vibrations are less likely to be transmitted to the pad 12.

[0122] [Experiment 3] The module of Example 4 was used to detect changes in pressure in spaces 11 and 13 due to vital vibrations and disturbance vibrations. Pad 12 was made of polyethylene. The other components were made by cutting acrylic plates. Instant adhesive was applied to the cut components to a thickness of 0.1 mm, and then the components were joined together.

[0123] The dimensions of each component are as follows: Plate member 55: Diameter φ=25mm, Z=3mm Upper plate 52a: X×Y×Z=55mm×55mm×3mm Opening 57: Diameter φ=30mm Lower plate 52b:X×Y×Z=55mm×55mm×3mm Side plate 52c: X, Y = 55 mm (width) x 5 mm (thickness), Z = 3 mm A hole (X, Y x Z = 8 mm x 15 mm x 3 mm) for the tube 26 is formed on one surface of the side plate 52c. The upper plate 52a, the lower plate 52b and the side plate 52c were bonded together using an adhesive with a thickness of 0.1 mm. Push part 16a: Diameter φ=15mm, Z=2mm Pad 12: X x Y x Z = 40 mm x 40 mm x 8 mm, thickness is 1 mm

[0124] A recess was made in the center of a cushion made of urethane and measuring X×Y×Z=300 mm×300 mm×60 mm, and the fabricated module 10 was placed in the recess. The module of Example 4 was installed in a car seat of a vehicle, and the vital signs of a passenger seated in the car seat were detected.

[0125] FIG. 19(a) shows the output signal of sensor 20a over time in Experiment 3, and FIG. 19(b) shows the spectrum obtained by Fourier transforming the output signal for period 72 in FIG. 19(a). In FIG. 19(a), period 72 is the period when a vehicle passed over a flat road surface, and period 73 is the period when the vehicle passed over an uneven road surface with construction marks. The output signal noise is high during period 73, but low during period 72. As shown in FIG. 19(b), when the output signal for period 72 is Fourier transformed, a signal peak 74 corresponding to respiration and a signal peak 75 corresponding to pulse are obtained. No peaks corresponding to respiration or pulse were observed during period 73. In this way, vital signals corresponding to respiration and pulse can be detected, although they depend on the road surface condition. It is also possible to monitor road surface conditions (e.g., ruts, construction marks, cracks, natural undulations, whether the road is paved, etc.).

[0126] According to the fourth embodiment, the side plates 52c and the upper plate 52a (housing) surround the pad 12 together with the lower plate 52b (second pressing portion), and are spaced apart from the pad 12. Furthermore, an opening 57 is provided in the upper plate 52a, and the side surface of the opening 57 is spaced apart from the pressing portion 16. This allows the portion of the housing 52 consisting of the side plates 52c and the upper plate 52a to suppress the transmission of disturbance vibrations to the pad 12. This improves the detection accuracy of vital vibrations.

[0127] Upper plate 52a (portion) of housing 52 is provided away from upper surface 12a of pad 12 and has opening 57 through which pressing portion 16 passes. This allows housing 52 to surround pad 12 from above, thereby further improving the detection accuracy of vital vibrations.

[0128] [Modification 1 of Example 4] Fig. 20 is a cross-sectional view of a module in Modification 1 of Example 4. As shown in Fig. 20, a pressing portion 18 is provided between the lower surface 12b and the lower plate 52b. The pressing portion 18 contacts the pad 12 and the lower plate 52b. In Modification 1 of Example 4, the pressing portion 18 and the lower plate 52b correspond to the second pressing portion. The area where the pressing portion 18 contacts the lower surface 12b is preferably smaller than the area where the pressing portion 16 contacts the upper surface 12a, and is preferably at least two times larger, and more preferably at least four times larger. [Example]

[0129] [Horizontal arrangement of two overlapping pads] Example 5 is an example of module installation. Fig. 21(a) is a cross-sectional view of a module in Comparative Example 5, and Fig. 21(b) is a cross-sectional view of a module in Example 5. In Fig. 21(a) and Fig. 21(b), the downward direction is the direction of gravity, i.e., the vertical direction, and is the center line 67 of pads 12 and 14.

[0130] As shown in FIG. 21(a), in Comparative Example 5, the upper surface 12a and lower surface 12b of pad 12 and the upper surface 14a and lower surface 14b of pad 14 are inclined relative to the vertical direction. The direction of force 68 from pressing portion 16 to pad 12 presses the center of pad 12 and is inclined relative to the Z direction, which is the normal direction to the upper surface 12a and lower surface 12b. As a result, force 68 is divided into a component force 68a in the -Z direction and a component force 68b in the X direction. As mentioned above, in order to detect vital vibrations, it is preferable to press the centers of pads 12 and 14 as closely as possible. However, because force 68 is inclined relative to the center of pad 12, the effective component force is component force 68a, which is weakened.

[0131] 21(b), in Example 5, the upper surface 12a and the lower surface 12b of the pad 12 and the upper surface 14a and the lower surface 14b of the pad 14 are arranged horizontally and substantially perpendicular to the vertical direction. In order to efficiently apply force to the pads 12 and 14, it is preferable that the direction of the applied force is perpendicular to the surfaces of the pads 12 and 14.

[0132] 22(a) and 22(b) are cross-sectional views of a car seat in which a module according to a fifth embodiment is installed. FIG. 22(a) is a cross-sectional view of a car seat 41 cut in the left-right direction, and FIG. 22(b) is a cross-sectional view of the car seat 41 cut in the front-to-back direction. As shown in FIGS. 22(a) and 22(b), the upper surface of the seat cushion 44 of the car seat 41 is inclined downward toward the rear. This is to protect the occupant in the event of a frontal vehicle collision. The module 10 is installed horizontally so that the upper and lower surfaces of the pads 12 and 14 are approximately perpendicular to the vertical direction. This allows the occupant's vital signs vibrations to be applied perpendicular to the surfaces of the pads 12 and 14, improving detection accuracy. Note that being approximately perpendicular to the vertical direction allows for an inclination of approximately ±10° or ±5° with respect to a horizontal plane perpendicular to the vertical direction. [Example]

[0133] [Humanity sensor] Example 6 is an example of a seating determination device that determines whether an object, such as 40 kg of rice, is a person or luggage when it is placed on the passenger seat or driver's seat. This can prevent an alarm from sounding to indicate that a seat belt is not fastened when rice is placed there. Furthermore, this can prevent the engine from starting even when no passenger is in the vehicle during autonomous driving. The modules of Examples 1 to 5 may be installed on a car seat as shown in FIG. 3 or FIGS. 22(a) and 22(b), and the processing unit 34 of FIG. 2 may determine whether a passenger is seated in the car seat 41. Furthermore, installing a temperature sensor in the vehicle interior enables the following determination and alarm notification. For example, the determination device uses the human presence sensor of Example 6 to determine whether a person is present in the vehicle interior. The determination device determines that a person is present in the vehicle interior, and issues an alarm if the room temperature in the vehicle interior exceeds, for example, 20°C and the vehicle has been parked for more than a predetermined time. The determination device may issue an alarm by sound outside the vehicle, or may issue an alarm to a mobile device of the driver using wireless communication means such as BLE (Bluetooth (registered trademark) Low Energy).

[0134] [Experiment 4] The module used in Experiment 2 of Example 3 was placed inside a urethane cushion in the rear seat of a vehicle. The output signals of the differential pressure sensor 20 were acquired when a passenger sat on the cushion and when 40 kg of rice was placed on the cushion. Reference vital signals were acquired from the passenger's chest. The passenger's vital signals were acquired while the vehicle was traveling at 40 km / h, while the signals when rice was placed were acquired while the vehicle was traveling at 20 km / h. The sampling frequency was 133.3 Hz, the Fourier transform had 2048 blocks, the calculation method was a 30-second average, and the upper frequency limit was 0.5 Hz. More specifically, with a sampling frequency of 133.3 Hz and 2048 Fourier transform blocks, the measurement time was 15.4 seconds. Because respiratory rate varies significantly among individuals, a measurement time of 15.4 seconds was too short, so analysis was performed using a 30-second average. In addition, the upper frequency limit was set to 0.5 Hz, so the maximum number of breaths per minute was limited to 30, and spectral components above 0.5 Hz were not considered to be breathing.

[0135] Figures 23(a) to 23(d) show the output signal of the differential pressure sensor over time in Experiment 4. The solid lines in Figures 23(a) and 23(b) show the output signal of the differential pressure sensor 20 when a passenger (human body) is seated. The reference signal ref is a reference vital signal obtained from the passenger's chest, measured simultaneously with the acquisition of the output signal of the differential pressure sensor 20. The output signal was acquired twice, in Figures 23(a) and 23(b). The solid lines in Figures 23(c) and 23(d) show the output signal when 40 kg of rice was placed on the cushion. The reference signal ref is a reference vital signal obtained from the chest of the passenger who was also seated. The output signal was acquired twice, in Figures 23(c) and 23(d).

[0136] As shown in Figures 23(a) and 23(b), in the human body, the output signal of the differential pressure sensor 20 shows the same tendency as ref. On the other hand, as shown in Figures 23(c) and 23(d), in the rice, the output signal of the differential pressure sensor 20 shows behavior that is unrelated to ref.

[0137] In Figures 23(a) to 23(d), the period 76 was divided into seven intervals. Each interval contained 2048 data points. Each interval was subjected to Fourier transform and spectral analysis. As a result, seven spectra were obtained for each of Figures 23(a) to 23(d).

[0138] Figures 24(a) to 24(g) show the results of the spectrum analysis of Figure 23(a) for the first human subject in Experiment 4. Figures 25(a) to 25(g) show the results of the spectrum analysis of Figure 23(b) for the second human subject. The solid line shows the spectrum of the output signal of differential pressure sensor 20, and the dotted line shows the spectrum of reference signal ref. As shown in Figures 24(a) to 25(g), a peak corresponding to the respiratory component is observed near 0.2 to 0.3 Hz, as indicated by arrow 58, in the spectrum of the reference signal. In Figures 24(a), 24(b), 24(d) to 24(g), 25(a) to 25(c), 25(e), and 25(f), a peak considered to be the respiratory component can be observed near arrow 58 of reference signal ref in the spectrum of the output signal of differential pressure sensor 20.

[0139] Figures 26(a) to 26(g) show the results of the spectral analysis of Figure 23(c) for the first test in Experiment 4. Figures 27(a) to 27(g) show the results of the spectral analysis of Figure 23(d) for the second test. The solid line shows the spectrum of the output signal of differential pressure sensor 20, and the dotted line shows the spectrum of reference signal ref. As shown in Figures 26(a) to 27(g), a peak corresponding to the respiratory component is observed in the vicinity of 0.2 to 0.3 Hz, as indicated by arrow 58, in the spectrum of the reference signal. However, no peak considered to be a respiratory component is observed in the vicinity of arrow 58 of reference signal ref in the spectrum of the output signal of differential pressure sensor 20.

[0140] An example of a flow in which the processing unit 34 cooperates with software to function as a determination unit that determines whether a passenger is seated in the car seat 41 will be described. FIGS. 28(a) and 28(b) are flowcharts illustrating the processing of the processing unit in Example 6. As shown in FIG. 28(a), the processing unit 34 acquires the output signal of the differential pressure sensor 20 for a predetermined period (step S10). The processing unit 34 performs a Fourier transform on the acquired output signal (step S12). The processing unit 34 determines whether the Fourier-transformed spectrum has a peak in a specific frequency range (e.g., 0.2 Hz to 0.5 Hz) (step S14). If the result is Yes, the processing unit 34 determines that a passenger is seated in the car seat 41 (step S16). If the result is No, the processing unit 34 determines that a passenger is not seated in the car seat 41 (step S18). The processing then ends. In this way, the processing unit 34 can determine whether a passenger is seated in the car seat 41.

[0141] As shown in FIG. 28(b), the processing unit 34 sets i=0 and j=0 (step S20). The processing unit 34 sets i=i+1 (step S22). The processing unit 34 performs steps S10, S12, and S14 in the same manner as in FIG. 28(a). If the answer is Yes in step S14, the processing unit 34 sets j=j+1 (step S24). If the answer is No, the processing unit 34 does not perform step S24. The processing unit 34 determines whether i=n (step S26). n is a natural number equal to or greater than 2 and is set in advance. If the answer is No, the processing returns to step S22. If the answer is Yes, the processing unit 34 determines whether j / n>k (step S28). k is a value greater than 0 and less than 1. If the answer is Yes, the processing unit 34 determines that a passenger is seated in the car seat 41 (step S30). If the answer is No, the processing unit 34 determines that no passenger is seated in the car seat 41 (step S32), and then ends the process.

[0142] As shown in Figures 24(a) to 25(g), even if a passenger is seated in the car seat 41, there are cases where no peak occurs in a specific frequency range. In Figure 28(b), the presence or absence of a peak in the respiratory component is determined for n different periods, and if the proportion j / n at which a peak exists is greater than a predetermined proportion k, it is determined that the passenger is seated in the car seat 41. This makes it possible to more accurately determine whether the passenger is seated in the car seat 41. Note that n and k may be changed depending on the situation. For example, when the vehicle is stopped, the disturbance vibration is small. Therefore, n is made small and k is made large. For example, when the vehicle is traveling fast, the disturbance vibration is large. Therefore, n is made large and k is made small.

[0143] According to the sixth embodiment, a module including pads 12, 14 and pressing portions 16 and 18 is provided in a car seat 41 of a vehicle, and a determination portion determines whether or not an occupant is seated in the seat based on the output of differential pressure sensor 20. This makes it possible to accurately determine whether or not an occupant is seated in car seat 41. Module 10 can be provided in the driver's seat, passenger seat, or rear seat of a vehicle.

[0144] When the subject is seated, the buttocks are the most suitable vibration source for vital signs, etc. Therefore, as shown in Figure 4, pads 12 and 14 are preferably provided so as to overlap the subject's buttocks or other body parts that bear weight (for example, the right or left buttock). Pads 12 and 14 may be provided so as to overlap the vibration source for vital signs, etc., such as the subject's thighs.

[0145] FIG. 29 is a flowchart showing a detection method in Example 6. As shown in FIG. 29, the modules of Examples 1 to 3 and their modifications are embedded in a seat of a four-wheeled vehicle (step S40). At this time, vibrations transmitted to at least one of pads 12 and 14 are adjusted by a pressing portion that contacts the pad (step S42). The pads may be arranged so that the vital vibrations of the occupant are mainly transmitted to pad 12 or 14. Differential pressure sensor 20 detects the difference between the gas pressure in pad 12 and the gas pressure in pad 14 (step S44). Processing unit 34 analyzes the pressure difference between pads 12 and 14 (step S46). Processing unit 34 determines the state of the vital vibrations of the occupant (step S48). In step S48, it may be determined whether an object placed on the seat is a person or luggage.

[0146] In Example 6, an example was described in which vital vibrations of a passenger are detected and the state of the vital vibrations is determined, but it is also possible to detect vibrations of drive noise or vibrations of the vehicle's drive motor and determine the state of the drive noise or the state of the drive motor.

[0147] In WO 2020 / 158952, instead of the piezoelectric element, a capacitance sensor, an electret condenser microphone, a piezoresistance sensor, a differential transformer, or the like may be used.

[0148] As can be seen from the above description, in the first to sixth embodiments, the processing unit 34 mainly detects vital vibrations from the pads 12 and 14. However, as explained with reference to FIGS. 12, 17, and 19(a), road noise is detected because road noise saturation is suppressed. Therefore, the processing unit 34 may detect road noise and perform calculations on the road noise. A vehicle control device may determine the fuel efficiency of the vehicle or control the vehicle speed based on the vibration of the road noise. Furthermore, the processing unit 34 may detect vibrations of a vehicle drive motor. For example, the processing unit 34 may extract abnormal sounds from the wheel drive motor, and the vehicle control device may control the vehicle to slow down or stop when the abnormal sound is detected.

[0149] Furthermore, based on the road noise detected by the processing unit 34, the vehicle control device may notify the driver of the current road conditions or fuel efficiency, or may link with a navigation system to provide guidance on an alternative route. Furthermore, the vehicle control device may store the detected road noise information in the cloud. The vehicle control device may notify the driver of the fuel efficiency or degree of fatigue caused by driving when traveling on the estimated road surface obtained from the cloud, or may suggest a driving route to the driver accordingly, or may make an announcement to prevent accidents.

[0150] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist of the present invention as defined in the claims.

[0151] In addition, the following features are further disclosed in relation to the above description. (Feature 1) a bag-shaped first member having a first surface and a second surface facing each other and filled with gas; a bag-shaped second member having a third surface and a fourth surface facing each other, the third surface facing the second surface, and filled with gas; a first pressing portion that is located at the center of the first surface when viewed from the stacking direction of the first member and the second member, that does not come into contact with the first surface when no force is applied in the direction of the first surface or when the force is small, and that comes into contact with the first surface when the force is large, or that has a small area of ​​contact with the first surface when no force is applied or when the force is small, and a large area of ​​contact with the first surface when the force is large; a second pressing portion contacting at least a central portion of the fourth surface; a module comprising: a detector that detects a difference between the gas pressure in the first member and the gas pressure in the second member; A biological information detection device comprising: (Feature 2) The biological information detection device according to Feature 1, wherein the surface of the first pressing portion facing the first surface has a central portion that protrudes toward the first surface more than the peripheral portion. (Feature 3) The biological information detection device according to Feature 1, wherein the central portion of the first surface protrudes toward the first pressing portion relative to the peripheral portion. (Feature 4) 4. The biological information detecting device according to any one of Features 1 to 3, wherein the second surface and the third surface are in contact with each other. (Feature 5) the module includes a separator provided between the second surface and the third surface and in contact with peripheral edges of the second surface and the third surface; 5. The biological information detection device according to any one of Features 1 to 4, wherein the second surface and the third surface are separated by the separator. (Feature 6) The biological information detection device according to any one of features 1 to 5, wherein the module includes a support member that surrounds the first member and the second member and connects the first pressing portion and the second pressing portion. (Feature 7) The module comprises: a plate-like member provided on the opposite side of the first pressing portion from the first member and spaced apart from the first pressing portion; a shaft member that connects a center portion of the plate-shaped member and a center portion of the first pressing portion and has a planar area smaller than the planar area of ​​the plate-shaped member; 7. The biological information detecting device according to any one of features 1 to 6, comprising: (Feature 8) a bag-shaped first member having a first surface and a second surface facing each other and filled with gas; a bag-shaped second member having a third surface and a fourth surface facing each other, the third surface facing the second surface, and filled with gas; a third member provided on the opposite side of the first member from the second member and spaced apart from the first surface; a first pressing portion that is located in a central portion of the first surface between the first surface and the third member, and that does not come into contact with either the first member or the third member when no force is applied from the third member in a direction toward the first surface or when the force is small, and that comes into contact with the one member when the force is large, or that has a small area of ​​contact with the one member when the force is not applied or when the force is small, and that has a large area of ​​contact with the one member when the force is large; a second pressing portion contacting at least a central portion of the fourth surface; a third pressing portion located on a peripheral edge of the first surface between the first surface and the third member, and contacting the first surface and the third member regardless of the force; a module comprising: a detector that detects a difference between the gas pressure in the first member and the gas pressure in the second member; A biological information detection device comprising: (Feature 9) The biological information detection device according to feature 8, wherein the module includes a support member that surrounds the first member and the second member and connects the third member and the second pressing portion. (Feature 10) the module includes a separator provided between the second surface and the third surface and in contact with peripheral edges of the second surface and the third surface; 10. The biological information detection device according to feature 8 or 9, wherein the second surface and the third surface are separated by the separator. (Feature 11) The module comprises: a plate-like member provided on the opposite side of the third member from the first member and spaced apart from the third member; a shaft member connecting a center portion of the plate-like member and a center portion of the third member; 11. The biological information detecting device according to any one of features 8 to 10, comprising: (Feature 12) a bag-shaped first member having a first surface and a second surface facing each other and filled with gas; a bag-shaped second member having a third surface and a fourth surface facing each other, the third surface facing the second surface, and filled with gas; a first pressing portion in contact with a central portion of the first surface; a second pressing portion that contacts at least a central portion of the fourth surface and has an area that contacts the fourth surface larger than an area that the first pressing portion contacts the first surface; a third pressing portion in contact with a peripheral edge portion of the first surface; a support member that surrounds the first member and the second member and connects the second pressing portion and the third pressing portion; a module comprising: a detector that detects a difference between the gas pressure in the first member and the gas pressure in the second member; A biological information detection device comprising: (Feature 13) The biological information detection device according to Feature 12, wherein the first pressing portion is spaced apart from the third pressing portion. (Feature 14) The biological information detection device according to feature 12 or 13, wherein the second surface and the third surface are in contact with each other. (Feature 15) a bag-shaped member having a first surface and a second surface facing each other and filled with a gas; a first pressing portion in contact with a central portion of the first surface; a second pressing portion in contact with at least a central portion of the second surface; a housing connected to the second pressing portion, surrounding the member at a distance, and spaced from the first pressing portion; a module comprising: a detector for detecting a gas pressure within the member; A biological information detection device comprising: (Feature 16) A biological information detection device as described in Feature 15, wherein the housing is provided on the opposite side of the member from the second pressing portion, away from the first surface, and has a portion having an opening through which the first pressing portion passes. (Feature 17) The biometric information detection device described in feature 15 or 16, wherein the module is provided on the opposite side of the member from the second pressing portion, away from the first surface, and includes a plate-shaped member whose center is in contact with the first pressing portion. (Feature 18) a bag-shaped first member having a first surface and a second surface facing each other and filled with gas; a bag-shaped second member having a third surface and a fourth surface facing each other, the third surface facing the second surface, and filled with gas; a first pressing portion in contact with at least a central portion of the first surface; a second pressing portion contacting at least a central portion of the fourth surface; a separator provided between the second surface and the third surface and in contact with peripheral edges of the second surface and the third surface; a module comprising: a separator separating the second surface from the third surface; a detector that detects a difference between the gas pressure in the first member and the gas pressure in the second member; A biological information detection device comprising: (Feature 19) a bag-shaped first member having a first surface and a second surface facing each other and filled with gas; a bag-shaped second member having a third surface and a fourth surface facing each other, the third surface facing the second surface, and filled with gas; a first pressing portion in contact with at least a central portion of the first surface; a second pressing portion contacting at least a central portion of the fourth surface; a plate-like member provided on the opposite side of the first pressing portion from the first member and spaced apart from the first pressing portion; a shaft member that connects a center portion of the plate-shaped member and a center portion of the first pressing portion and has a planar area smaller than the planar area of ​​the plate-shaped member; a module comprising: a detector that detects a difference between the gas pressure in the first member and the gas pressure in the second member; A biological information detection device comprising: (Feature 20) 15. The biological information detection device according to any one of features 1 to 14, wherein the first surface, the second surface, the third surface, and the fourth surface are arranged in a direction substantially perpendicular to a vertical direction. (Feature 21) a bag-shaped first member having a first surface and a second surface facing each other and filled with gas; a bag-shaped second member having a third surface and a fourth surface facing each other, the third surface facing the second surface, and filled with gas; a first pressing portion in contact with at least a central portion of the first surface; a second pressing portion contacting at least a central portion of the fourth surface; a module comprising: a detector that detects a difference between the gas pressure in the first member and the gas pressure in the second member; Equipped with The biological information detection device has the first surface, the second surface, the third surface, and the fourth surface arranged in a direction substantially perpendicular to the vertical direction. (Feature 22) The biological information detection device according to Feature 21, wherein the second surface and the third surface are in contact with each other. (Feature 23) 23. The biological information detection device according to feature 21 or 22, wherein the module is installed in a seat of a vehicle. (Feature 24) The biological information detection device according to any one of Features 1 to 14 and 18 to 23; a determination unit that determines whether or not a passenger is seated in a seat of a vehicle in which the module is installed, based on an output of the detector; A seating determination device comprising: (Feature 25) a bag-shaped first member having a first surface and a second surface facing each other and filled with gas; a bag-shaped second member having a third surface and a fourth surface facing each other, the third surface facing the second surface, and filled with gas; a first pressing portion in contact with at least a central portion of the first surface; a second pressing portion contacting at least a central portion of the fourth surface; a module provided in a seat of a vehicle; a detector that detects a difference between the gas pressure in the first member and the gas pressure in the second member; a determination unit that determines whether or not a passenger is seated in the seat based on an output of the detector; A seating determination device comprising: (Feature 26) a module including a bag-shaped first member filled with gas, a bag-shaped second member layered under the first member and filled with gas, a first pressing portion abutting the upper surface of the first member, a second pressing portion abutting the lower surface of the second member, a first tube communicating with the first member, a second tube communicating with the second member, and a differential pressure sensor that detects a difference in pressure between the gas in the first member and the gas in the second member via the first tube and the second tube, wherein at least the first member, the second member, the first pressing portion, and the second pressing portion are embedded in a sheet; At least one of the first member and the second member adjusts vibrations transmitted to the at least one member by a pressing portion of the first pressing portion and the second pressing portion that contacts the at least one member, A detection method for detecting a difference between the pressure of the gas in the first member and the pressure of the gas in the second member. (Feature 27) The module is embedded in a seat of a four-wheeled vehicle and is positioned so that the vital vibrations of the occupant, the vibrations of drive noise, or the vibrations of the drive motor are mainly transmitted to either the first member or the second member, and the detection method described in feature 26 determines the state of the vital vibrations of the occupant, the state of drive noise, or the state of the drive motor by analyzing the difference in gas pressure between the first member and the gas pressure in the second member. (Feature 28) The detection method according to feature 27, wherein the module is embedded in a seat of a four-wheeled vehicle and determines whether an object placed on the seat is a person or luggage. [Explanation of symbols]

[0152] 10 modules 11, 13, 21, 23 space 12, 14 pads 12a, 14a top surface 12b, 14b bottom surface 16, 16a, 16b, 18 Push part 20 Differential pressure sensor 22 Case 24 Vibrating membrane 25 Sensor element 41 Car Seat 52 Case 52a Upper board 52b Lower plate 52c side plate 54 Shaft core member 55, 56 Plate-shaped members 57 Aperture

Claims

1. a bag-shaped first member having a first surface and a second surface facing each other and filled with gas; a bag-shaped second member having a third surface and a fourth surface facing each other, the third surface facing the second surface, and filled with gas; a first pressing portion located at a center portion of the first surface when viewed from a stacking direction of the first member and the second member; a second pressing portion contacting at least a central portion of the fourth surface; a module comprising: a detector that detects a difference between the gas pressure in the first member and the gas pressure in the second member; Equipped with a distance between the first surface and a fifth surface of the first pressing portion that faces the first surface becomes shorter from the peripheral edge portion toward the center portion, A biological information detection device in which vibrations can be transmitted between the first surface and the fifth surface.

2. The biological information detecting device according to claim 1 , wherein a central portion of the surface of the first pressing portion facing the first surface protrudes toward the first surface more than a peripheral portion thereof.

3. The biological information detection device according to claim 1 , wherein a central portion of the first surface protrudes toward the first pressing portion relative to a peripheral edge portion.

4. The biological information detection device according to claim 1 , wherein the second surface and the third surface are in contact with each other.

5. the module includes a separator provided between the second surface and the third surface and in contact with peripheral edges of the second surface and the third surface; The biological information detection device according to claim 1 , wherein the second surface and the third surface are separated by the separator.

6. The biological information detection device according to claim 1 , wherein the module includes a support member that surrounds the first member and the second member and connects the first pressing portion and the second pressing portion.

7. The module comprises: a plate-like member provided on the opposite side of the first pressing portion from the first member, the plate-like member being spaced apart from the first pressing portion; a shaft member that connects a center portion of the plate-like member and a center portion of the first pressing portion and has a planar area smaller than the planar area of ​​the plate-like member; The biological information detection device according to claim 1 , further comprising:

8. The biological information detection device according to claim 1 , wherein the first surface, the second surface, the third surface, and the fourth surface are arranged in a direction substantially perpendicular to a vertical direction.

9. The module comprises: a third member provided on the opposite side of the first member with respect to the first pressing portion; a third pressing portion located on a peripheral edge of the first surface between the first surface and the third member and in contact with the first surface and the third member; Equipped with The biological information detection device according to claim 1 , wherein vibrations can be transmitted between the first surface and the third member via the first pressing portion.

10. The biological information detection device according to claim 9 , wherein the module includes a support member that surrounds the first member and the second member and connects the third member and the second pressing portion.

11. the module includes a separator provided between the second surface and the third surface and in contact with peripheral edges of the second surface and the third surface; The biological information detection device according to claim 9 or 10, wherein the second surface and the third surface are separated by the separator.

12. The module comprises: a plate-like member provided on the opposite side of the third member from the first member and spaced apart from the third member; a shaft member connecting a center portion of the plate-like member and a center portion of the third member; The biological information detection device according to claim 9 or 10, comprising:

13. a bag-shaped first member having a first surface and a second surface facing each other and filled with gas; a bag-shaped second member having a third surface and a fourth surface facing each other, the third surface facing the second surface, and filled with gas; a first pressing portion in contact with at least a central portion of the first surface; a second pressing portion contacting at least a central portion of the fourth surface; a plate-like member provided on the opposite side of the first pressing portion from the first member, the plate-like member being spaced apart from the first pressing portion; a shaft member that connects a center portion of the plate-like member and a center portion of the first pressing portion and has a planar area smaller than the planar area of ​​the plate-like member; a module comprising: a detector that detects a difference between the gas pressure in the first member and the gas pressure in the second member; A biological information detection device comprising:

14. a bag-shaped first member having a first surface and a second surface facing each other and filled with gas; a bag-shaped second member having a third surface and a fourth surface facing each other, the third surface facing the second surface, and filled with gas; a first pressing portion in contact with at least a central portion of the first surface; a second pressing portion contacting at least a central portion of the fourth surface; a module comprising: a detector that detects a difference between the gas pressure in the first member and the gas pressure in the second member; Equipped with The biological information detection device is such that the first surface, the second surface, the third surface, and the fourth surface are arranged in a direction substantially perpendicular to the vertical direction.

15. The biological information detection device according to claim 14 , wherein the second surface and the third surface are in contact with each other.

16. The biological information detection device according to claim 14 or 15, wherein the module is installed in a seat of a vehicle.

17. The biological information detection device according to any one of claims 1, 13 and 14; a determination unit that determines whether or not a passenger is seated in a seat of a vehicle in which the module is installed, based on an output of the detector; A seating determination device comprising:

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