Pulse wave measuring device

Abstract

To provide a pulse wave measuring device that can notify a user of the pulse wave measuring device of capturing a pulse wave.SOLUTION: A pulse wave measuring device includes: a housing capable of being worn by a finger; a pulse wave sensor fixed to a part of the housing positioned on a front side of the finger; an amplifier for receiving an output signal of the pulse wave sensor and outputting an amplification signal formed by amplifying the output signal; and an output device for receiving the amplification signal and operating in accordance with the amplification signal.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a pulse wave measuring device. [Background technology]

[0002] 2. Description of the Related Art Pulse wave measuring devices are known that can measure pulse waves propagating from an artery by contacting a pulse wave sensor with the skin of a subject's neck, wrist, or the like. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2021-137269 A Summary of the Invention [Problem to be solved by the invention]

[0004] In such a pulse wave measuring device, it is desirable to place the pulse wave sensor at an appropriate position on the human body (for example, on the skin directly above the radial artery or ulnar artery). For example, Patent Document 1 discloses a technique in which, in a pulse wave measuring pad having multiple piezoelectric elements, the pulse wave measurement values ​​from each piezoelectric element are compared, and an actuator at a position corresponding to the piezoelectric element showing the maximum pulse wave measurement value is vibrated. In this way, Patent Document 1 can guide the user to place the center of the pulse wave measuring pad directly above the carotid artery.

[0005] The present invention has been made in consideration of the above-mentioned points, and has an object to provide a pulse wave measuring device that can notify a user that a pulse wave has been detected by a pulse wave sensor. [Means for solving the problem]

[0006] A pulse wave measuring device according to one embodiment of the present disclosure comprises a housing that can be worn on a finger, a pulse wave sensor fixed to a portion of the housing that is located on the palm side of the finger, an amplifier that receives an output signal from the pulse wave sensor and outputs an amplified signal that amplifies the output signal, and an output device that receives the amplified signal and operates in accordance with the amplified signal. Effect of the Invention

[0007] According to the disclosed technique, it is possible to realize a pulse wave measuring device that can notify a user that a pulse wave has been detected by a pulse wave sensor. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic diagram illustrating a pulse wave measuring device according to a first embodiment; [Diagram 2] 2 is a view of the pulse wave measuring device according to the first embodiment, as viewed from the direction of arrow P in FIG. [Diagram 3] 2 is a view of the pulse wave measuring device according to the first embodiment, as viewed from the arrow Q side in FIG. [Figure 4] 1 is a plan view illustrating a pulse wave sensor according to a first embodiment. [Diagram 5] 1 is a cross-sectional view illustrating a pulse wave sensor according to a first embodiment. [Figure 6] This is an example of a bridge circuit. [Figure 7] 3 is a diagram showing a state in which a cover member is attached to the pulse wave sensor according to the first embodiment. FIG. [Figure 8] FIG. 2 is a plan view illustrating the strain gauge according to the first embodiment. [Figure 9] 1 is a cross-sectional view (part 1) illustrating a strain gauge according to a first embodiment. FIG. [Figure 10] 4 is a cross-sectional view (part 2) illustrating the strain gauge according to the first embodiment. FIG. [Figure 11] 13 is a diagram showing a state in which a cover member is attached to a pulse wave sensor according to a first modified example of the first embodiment. FIG. [Figure 12] 2 is a view of a pulse wave measuring device according to a second modified example of the first embodiment, as viewed from the side indicated by the arrow P in FIG. [Figure 13] 2 is a view of a pulse wave measuring device according to a second modified example of the first embodiment, as viewed from the side indicated by the arrow Q in FIG. [Figure 14] 1. FIG. 4 is a view of a pulse wave measuring device according to a third modified example of the first embodiment, as viewed from the side indicated by the arrow P in FIG. [Figure 15] 1. FIG. 4 is a diagram showing a pulse wave measuring device according to a third modified example of the first embodiment, as viewed from the side indicated by the arrow Q in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and duplicated explanations may be omitted.

[0010] First Embodiment [Pulse wave measuring device] Fig. 1 is a schematic diagram illustrating a pulse wave measuring device according to a first embodiment. Referring to Fig. 1, the pulse wave measuring device 1 has a housing 10, a pulse wave sensor 20, an amplifier 30, an output device 40, and an information processing device 50. Fig. 1 also shows fingers 200 of a subject (i.e., a person whose pulse wave is to be measured).

[0011] Fig. 2 is a view of the pulse wave measuring device according to the first embodiment as viewed from the side indicated by the arrow P in Fig. 1. Fig. 3 is a view of the pulse wave measuring device according to the first embodiment as viewed from the side indicated by the arrow Q in Fig. 1. For ease of viewing, the amplifier 30, output device 40, and information processing device 50 are not shown in Figs. 2 and 3.

[0012] As shown in Figs. 1 to 3, the housing 10 can be worn on a finger 200 of a user of the pulse wave measuring device 1 (hereinafter simply referred to as "user"). The user may be the same person as the subject, or may be a different person. In the example of Figs. 1 to 3, the housing 10 is in the form of a finger cot having a finger insertion section 10x that is open at one end and closed at the other end. The housing 10 can be made of, for example, rubber, cloth, resin, etc.

[0013] By making the housing 10 into a finger stall type as shown in the figure, it becomes easy to attach and detach the housing to the user's fingers. Furthermore, since the finger stall type housing 10 has a large contact area with the user's fingers, the housing 10 is unlikely to come off the fingers even if the pulse wave sensor 20 slides on the subject's skin during pulse wave measurement. In other words, the finger stall type housing 10 has the advantage of being able to stably support the pulse wave sensor 20.

[0014] 1 to 3 is merely an example, and is not limited to the illustrated shape as long as it can be worn on the user's finger 200. For example, the housing 10 may be a belt type having openings on both ends.

[0015] The pulse wave sensor 20 is fixed to the housing 10. The pulse wave sensor 20 may be fixed directly to the housing 10, or may be fixed to the housing 10 via another member. In the example of Figs. 1 to 3, the pulse wave sensor 20 is fixed via the output device 40 to a portion of the housing 10 located on the palm side of the fingers. When the first surface 22m comes into contact with the radial artery of the subject, the pulse wave sensor 20 detects the subject's pulse wave and outputs an output signal S1. The output signal S1 is, for example, a periodic analog voltage signal of about 1 Hz to 15 Hz.

[0016] The amplifier 30 amplifies the output signal S1 of the pulse wave sensor 20 and outputs an amplified signal S2. The amplifier 30 can amplify the output signal S1 of the pulse wave sensor 20 to a voltage level that can operate the output device 40. The output signal S1 of the pulse wave sensor 20 has a small amplitude, for example, about several mV. The amplitude of the amplified signal S2 is, for example, about several V. The amplifier 30 may have a function of amplifying a current in addition to a function of amplifying a voltage. The amplifier 30 does not have to be a physically independent device, and may be a circuit built into the pulse wave sensor 20, the housing 10, or the information processing device 50.

[0017] The amplifier 30 in this embodiment may perform processing other than amplification of the output signal S1, or may not perform processing other than amplification of the output signal S1. Processing other than amplification includes, for example, analog / digital conversion of the output signal S1, processing of the signal waveform of the output signal S1 such as noise removal, smoothing, normalization, and / or processing of analyzing the signal waveform of the output signal S1. The amplifier 30 performs amplification processing of the output signal S1 and the above-mentioned processing other than amplification on the output signal S1 in any order, and finally creates and outputs an amplified signal S2.

[0018] The hardware and software included in the amplifier 30 may be appropriately selected depending on the processing executed by the amplifier 30. For example, when the amplifier 30 only amplifies the output device S1, the amplifier 30 may be an amplifier circuit. When the amplifier 30 amplifies the output signal S1 and also removes noise or filters it, the amplifier 30 may be configured to include a circuit capable of performing such processing, as well as a control device and a program.

[0019] When the amplifier 30 does not perform any processing other than amplifying the output signal S1, the amplifier 30 creates and outputs an amplified signal S2 by amplifying the output signal S1 at a fixed ratio. Therefore, within the voltage range that the amplifier 30 can output, the amplitude of the output signal S1 and the amplitude of the amplified signal S2 are proportional. Furthermore, if the frequency characteristic of the amplifier 30 is ideal, the frequency components contained in the output signal S1 and the amplified signal S2 will match.

[0020] The amplifier 30 may be a discrete circuit formed by combining transistors, resistors, etc., or may be an integrated circuit. The amplifier 30 may be mounted on a flexible substrate or the like and placed in any free space inside or outside the housing 10. Alternatively, the amplifier 30 may be configured integrally with the pulse wave sensor 20 or the output device 40.

[0021] The output device 40 operates in response to the amplified signal S2 output by the amplifier 30. Here, "operating in response to the amplified signal S2" means, for example, operating in a manner linked with at least one of the presence or absence of output of the amplified signal S2, the magnitude of the output, the amplitude of the output, and the output waveform. The output device 40 can output, for example, vibration, light, and / or sound. When outputting vibration, the output device 40 is, for example, a vibration device such as a linear resonant actuator, a piezoelectric actuator, or an eccentric rotation motor. When outputting light, the output device 40 is, for example, a light emitting diode (Light Emitting Diode), an organic EL (Organic Electro Luminescence), or the like. When outputting sound, the output device 40 is, for example, a speaker, an earphone, a headphone, or the like. As a speaker, for example, a MEMS speaker can be given.

[0022] The linear resonant actuator has the advantage of being able to generate various vibration waveforms. Specifically, when a linear resonant actuator is used, it is possible to generate vibrations corresponding to the amplified signal S2. For example, the linear resonant actuator can reproduce vibrations similar to the undulations of a pulse wave at the position where the pulse wave sensor 20 is placed. In addition, the linear resonant actuator has the advantages of quick response to the supplied voltage and low power consumption.

[0023] On the other hand, when the output device 40 is a device that outputs light or sound, the output can be switched on and off depending on the presence or absence of the output of the amplified signal S2, or the intensity of the amplified signal S2 can be synchronized with the intensity of the light or sound. In this way, the specific structure of the output device 40 may be determined as appropriate.

[0024] When the amplifier 30 does not perform any process other than amplifying the voltage (and current) of the output signal S1, the pulse wave measuring device 1 does not need to perform complex process control for the operation of the output device 40. For example, it is not necessary to operate a control device such as a CPU or a DSP (Digital Signal Processor) to perform complex processes for the operation of the output device 40. Therefore, it is possible to drive the output device 40 in response to the output of the pulse wave sensor 20 with a simple path and device configuration. This can reduce the time lag between the signal output of the pulse wave sensor 20 and the response operation of the output device 40 to that output, for example.

[0025] Furthermore, when the amplifier 30 does not perform any process other than amplifying the output signal S1, the output signal S1 of the pulse wave sensor 20 may be input to the amplifier 30 without passing through any other device. Also, the amplified signal S2 of the amplifier 30 may be input to the output device 40 without passing through any other device.

[0026] On the other hand, regardless of whether the amplifier 30 performs processing other than amplifying the output signal S1, other devices may be inserted between the pulse wave sensor 20 and the amplifier 30, or between the amplifier 30 and the output device 40. The other devices referred to here are, for example, modulators that perform amplitude modulation or frequency modulation. For example, if the output device 40 is a device that outputs sound, by using a modulator, if the frequency of the output signal S1 from the pulse wave sensor 20 is outside the human audible range, it is possible to convert it into a frequency within the audible range before operating the output device 40.

[0027] In addition, when the output device 40 is a device that outputs vibration, the output device 40 is fixed to the housing 10 in order to transmit the vibration to the finger 200 via the housing 10. In the example of Figs. 1 to 3, the output device 40 is fixed to the same side of the housing 10 as the pulse wave sensor 20, but the arrangement of the output device 40 is not limited to this. The output device 40 may be fixed, for example, to the opposite side of the housing 10 to the pulse wave sensor 20 (such as a portion of the housing 10 located on the nail side of the finger 200 in Fig. 1). In addition, when the output device 40 outputs vibration, the output device 40 may be fixed to the inside of the housing 10 (i.e., the wall surface of the finger insertion section 10x) rather than to the outside.

[0028] When the output device 40 outputs light or sound, the output device 40 may or may not be fixed to the housing 10. For example, if the output device 40 is an earphone, the output device 40 is connected to the tip of a cable connected to the amplifier 30.

[0029] The information processing device 50 is a device for adjusting the received amplified signal S2 to a level where it can be monitored and / or analyzed as a pulse wave. An example of the information processing device 50 is a control device such as a personal computer or a smartphone. The information processing device 50 includes a control unit configured with a CPU, a DSP, or the like. The control unit receives the amplified signal S2 from the amplifier 30.

[0030] When the control unit receives the amplified signal S2, it performs various processing on the amplified signal S2. The content of the "various processing" may be appropriately determined according to the amplified signal S2. For example, the information processing device 50 may execute one or more of the following processing on the amplified signal S2: waveform processing such as digitization, noise removal, smoothing, and normalization, and / or arithmetic processing such as differentiation of the signal waveform. As a result, a regulated waveform that can analyze and monitor the state of the pulse wave is obtained from the amplified signal S2. Note that, if the amplified signal S2 is a signal that has been regulated to such an extent that it can be monitored as it is, the information processing device 50 may use the amplified signal S2 for monitoring without processing it.

[0031] The information processing device 50 may have one or more of a display and / or a storage device built in or attached externally. The information processing device 50 can display information obtained from the output signal S1, such as a pulse waveform, on the display and record the information in the storage device. The display and / or recording may be performed in real time. The information processing device 50 may have a built-in or external audio output device, such as a speaker.

[0032] In the pulse wave measuring device 1, a path for analyzing and / or monitoring the output signal S1 output from the pulse wave sensor 20 (hereinafter referred to as the first path) and a path for the operation of the output device 40 (hereinafter referred to as the second path) may be configured separately, or part or all of them may be the same path.

[0033] As an example of configuring the first path and the second path separately, as described above, there is a case where the amplified signal S2 created by the amplifier 30 is transmitted to both the output device 40 and the information processing device 50. In this case, the output device 40 outputs light, sound, and / or vibration according to the amplified signal S2, while the information processing device 50 adjusts the amplified signal S2 to a level that allows monitoring.

[0034] Another example of a configuration in which the first and second paths are separated is where the pulse wave sensor 20 transmits the output signal S1 to both the amplifier 30 and the information processing device 50. In this case, the information processing device 50 receives the output signal S1 rather than the amplified signal S2, and amplifies the output signal S2 by itself and performs various processing steps for adjustment. The amplifier 30 creates the amplified signal S2 from the output signal S1 and transmits the amplified signal S2 to the output device 40, separately from the information processing device 50.

[0035] In either case, by configuring the first path and the second path separately, the amplifier 30 can perform only the processing required to operate the output device 40. Therefore, the device configuration of the amplifier 30 can be simplified.

[0036] In contrast, an example of a configuration in which the first path and the second path are partly or entirely the same is an example in which the amplifier 30 is a part of the information processing device 50. In this case, the information processing device 50 receives the output signal S1, creates an amplified signal S2, and transmits the amplified signal S2 to the output device 40. This has the advantage that it is not necessary to provide a separate amplifier 30.

[0037] Another example of a configuration in which the first path and the second path are partly or entirely the same is an example in which the information processing device 50 has only a configuration as a display and / or audio output device. In this case, the amplifier 30 creates a monitored regulated amplified signal S2 and transmits it to the information processing device 50, or transmits a regulated signal S3 obtained by regulating the created amplified signal S2 to the information processing device 50. The information processing device 50 displays and / or outputs the received amplified signal S2 or regulated signal S3 as audio. This eliminates the need to prepare a special device as the information processing device 50. For example, it is possible to connect a commercially available display to the amplifier 30 and monitor the pulse wave on the display.

[0038] The operation of the pulse wave measuring device 1 according to this embodiment is summarized below. In the pulse wave measuring device 1, the pulse wave sensor 20 is fixed to a housing 10 that can be worn on a finger. Therefore, the housing 10 worn on the finger can be moved over the skin to locate the radial artery by the same operation as when the finger is directly touched to the skin to locate the radial artery. In addition, the housing 10 worn on the finger can adjust the pressure on the radial artery in the same way as when the finger is directly touched to the skin to measure the pulse wave.

[0039] Also, when the pulse wave sensor 20 detects the radial artery, the output device 40 operates in response to the amplified signal S2 obtained by amplifying the output signal S1 of the pulse wave sensor 20. For example, the output device 40 vibrates intermittently at the same timing as the pulse wave, and the vibration is transmitted to the fingers 200 via the housing 10. For example, the output device 40 vibrates with a strength corresponding to the strength of the pulse wave, and the vibration is transmitted to the fingers 200 via the housing 10. This allows the user to feel the same sensation as when the user directly touches the skin with the finger to feel the pulse wave. Therefore, the user can easily recognize that the pulse wave sensor 20 detects the radial artery or the ulnar artery. The same effect can be obtained when the output device 40 outputs light or sound instead of vibration.

[0040] That is, by using the pulse wave measuring device 1, the position of the subject's artery can be easily and quickly identified, and the pulse wave sensor 20 can be applied to the subject's skin with an appropriate pressing force. This allows the pulse wave to be measured accurately using the pulse wave measuring device 1. Furthermore, the pulse wave measuring device 1 does not require a measurement processing device that performs complicated operations as shown in Patent Document 1, or a complicated mechanical structure such as a radial artery position detection mechanism or a pressure mechanism, and is capable of feeding back the pulse wave to the user in the form of light, vibration, and / or sound with a simple configuration.

[0041] [Pulse wave sensor] Here, as an example of the pulse wave sensor 20, a pulse wave sensor having a plurality of strain gauges is shown.

[0042] Fig. 4 is a plan view illustrating the pulse wave sensor according to the first embodiment. Fig. 5 is a cross-sectional view illustrating the pulse wave sensor according to the first embodiment, taken along line AA in Fig. 4. 4 and 5, pulse wave sensor 20 has housing 21, strain body 22, wire 23, and a plurality of strain gauges (strain gauges 1001, 1002, 1003, 1004). Note that, unless there is a particular need to distinguish between them, strain gauges 1001, 1002, 1003, 1004 may be collectively referred to as strain gauge 100.

[0043] The flexure body 22 has a base portion 22a, a beam portion 22b, a load portion 22c, and an extension portion 22d. The flexure body 22 is in the shape of a flat plate. The flexure body 22 has a first surface 22m and a second surface 22n located on the opposite side to the first surface 22m.

[0044] The material of the flexure body 22 may be, for example, metal, ceramic, glass, etc. Examples of metals used for the material of the flexure body 22 include SUS (stainless steel), copper, aluminum, etc. The flexure body 22 may be integrally formed by, for example, etching or pressing. The thickness t of the flexure body 22 excluding the load portion 22c is constant. The thickness t is determined appropriately according to the material of the flexure body 22. For example, when the flexure body 22 is made of metal, the thickness may be 0.03 mm or more and 0.3 mm or less.

[0045] When the flexure body 22 is made of glass, it is desirable to determine the thickness of the flexure body 22 so that the breaking strength of the flexure body 22 is greater than 20 N in static pressure. In this case, the surface compressive stress of the flexure body 22 may be increased by chemically strengthening the glass of the flexure body 22.

[0046] In the explanation of Figs. 4 and 5, for convenience, the side of the pulse wave sensor 20 where the load portion 22c of the flexure body 22 is provided is referred to as the "upper side", and the side where the load portion 22c of the flexure body 22 is not provided is referred to as the "lower side". The surface located on the upper side of each part is referred to as the "upper surface", and the surface located on the lower side of each part is referred to as the "lower surface". However, the pulse wave sensor 20 can also be used upside down. The pulse wave sensor 20 can also be disposed at any angle. The planar view refers to viewing the object in the normal direction from the upper side to the lower side of the first surface 22m of the flexure body 22. The planar shape refers to the shape of the object when viewed in the normal direction.

[0047] In the pulse wave sensor 20, the housing 21 is a portion that holds the strain body 22. The housing 21 is a hollow cylinder with a closed bottom and an open top. The housing 21 can be made of, for example, metal or resin. The substantially disk-shaped strain body 22 is fixed with an adhesive or the like so as to close the opening on the top side of the housing 21.

[0048] In the flexure body 22, the base 22a is a circular frame-shaped (ring-shaped) region outside the circular dashed line shown in FIG. 4. The region inside the circular dashed line may be referred to as a circular opening. In other words, the base 22a of the flexure body 22 has a circular opening. The width w1 of the base 22a is, for example, 1 mm or more and 5 mm or less. The inner diameter d of the base 22a (i.e., the diameter of the circular opening) is, for example, 10 mm or more and 15 mm or less.

[0049] The beam portion 22b is provided so as to bridge the inside of the base portion 22a. The beam portion 22b has, for example, two beams that cross in a cross shape in a plan view, and the crossing region of the two beams includes the center of the circular opening. In the example of FIG. 4, one beam constituting the cross has the X direction as its longitudinal direction, and the other beam constituting the cross has the Y direction as its longitudinal direction, and they are perpendicular to each other. Each of the two perpendicular beams is preferably located inside the inner diameter d (diameter of the circular opening) of the base portion 22a and is as long as possible. In other words, it is preferable that the length of each beam is approximately equal to the diameter of the circular opening. In each beam constituting the beam portion 22b, the width w2 other than the crossing region is constant, and is, for example, 1 mm or more and 5 mm or less. It is not essential that the width w2 is constant, but it is preferable that the width w2 is constant in that the strain can be detected linearly.

[0050] The load portion 22c is provided on the beam portion 22b. The load portion 22c is provided, for example, in the region where the two beams constituting the beam portion 22b intersect. The load portion 22c protrudes from the upper surface of the beam portion 22b. The amount of protrusion of the load portion 22c based on the upper surface of the beam portion 22b is, for example, about 0.1 mm. The beam portion 22b is flexible, and elastically deforms when a load is applied to the load portion 22c. The upper surface of the beam portion 22b is part of the first surface 22m of the strain generating body 22. The load portion 22c is not an essential component.

[0051] The four extensions 22d are sector-shaped portions extending from the inside of the base 22a toward the beams 22b in a plan view. A gap of about 1 mm is provided between each extension 22d and the beams 22b. The extensions 22d do not contribute to the sensing of the pulse wave sensor 20, and therefore may not be provided.

[0052] The elastic body 22 may have a shape without a slit in the circular opening. That is, the circular opening of the base 22a may be integral with the beam 22b and the extension 22d. The elastic body 22 may be flush without the load portion 22c.

[0053] The wire 23 is a cable for inputting and outputting electrical signals between the pulse wave sensor 20 and the outside. When the amplifier 30 is a device separate from the pulse wave sensor 20, the wire 23 is connected to the amplifier 30. When the amplifier 30 is built into the housing 21, for example, a strain gauge circuit (such as a bridge circuit described below) in the pulse wave sensor 20 may be connected to the amplifier 30, and the wire 23 may be connected to the information processing device 50. The wire 23 may be a shielded cable, a flexible board, or the like. The wire 23 is not an essential component of the pulse wave sensor 20. The pulse wave sensor 20 may be configured to communicate with the outside by a method such as wireless communication, without using the wire 23.

[0054] The output signal S1 of the pulse wave sensor 20 is generated based on the outputs of a plurality of strain gauges. In the illustrated example, the pulse wave sensor 20 has a pair of strain gauges 1001 and 1002 arranged on a beam extending in the Y direction on the second surface 22n of the strain body 22, facing each other in a plan view with the load portion 22c therebetween. In addition, the pulse wave sensor 20 has another pair of strain gauges 1003 and 1004 arranged on a beam extending in the X direction intersecting the beam on which the pair of strain gauges 1001 and 1002 are arranged, facing each other in a plan view with the load portion 22c therebetween.

[0055] The strain gauges 1001 and 1002 detect the compressive strain of the strain body 22 that occurs in the beam extending in the Y direction when the load section 22c is pressed. The strain gauges 1003 and 1004 detect the tensile strain of the strain body 22 that occurs in the beam extending in the X direction when the load section 22c is pressed. The distance between the strain gauges 1001 and 1002 that detect the compressive strain is wider than the distance between the strain gauges 1003 and 1004 that detect the tensile strain. By arranging the strain gauges 100 in this manner, it is possible to effectively detect the compressive strain and the tensile strain and obtain a large output from the bridge circuit that constitutes a full bridge.

[0056] The strain gauges 1001 to 1004 are connected to form each side of a bridge circuit, and the output signal S1 of the pulse wave sensor 20 can be generated by the bridge circuit. Fig. 6 is an example of a bridge circuit. In the bridge circuit shown in Fig. 6, the strain gauge 1001 forms the upper left side. The strain gauge 1002 forms the lower right side. The strain gauge 1003 forms the upper right side. The strain gauge 1004 forms the lower left side.

[0057] 6, a DC voltage E is supplied between the connection between the upper left side and the lower left side and the connection between the upper right side and the lower right side. This allows an analog voltage output signal S1 to be obtained between the connection between the upper left side and the upper right side and the connection between the lower left side and the lower right side. The bridge circuit can be provided, for example, on a wiring board attached to the inside surface of the housing 21.

[0058] In pulse wave sensor 20, when load portion 22c comes into contact with the radial artery of the subject, a load is applied to load portion 22c in accordance with the subject's pulse wave, causing beam portion 22b to elastically deform, and changing the resistance value of the resistor in strain gauge 100. Pulse wave sensor 20 can detect the pulse wave based on the change in the resistance value of the resistor in strain gauge 100 that accompanies the deformation of beam portion 22b. The pulse wave is detected as a periodic voltage change from the bridge circuit as output signal S1.

[0059] In the above, an example has been shown in which the pulse wave sensor 20 has four strain gauges and generates the output signal S1 by connecting the four strain gauges in a full bridge configuration. However, the pulse wave sensor 20 may have two strain gauges and generate the output signal S1 by connecting the two strain gauges in a half bridge configuration.

[0060] A cover member may be provided so as to cover the entire flexure body 22 of the pulse wave sensor 20. For example, a cover member made separately from a material such as silicone may be attached to the flexure body 22 like a cap, or a material such as silicone may be integrally molded by a method such as insert molding so as to be joined to the flexure body 22. It is also desirable that the cover member has a gap between it and the flexure body 22. The method of attaching the cover member to the pulse wave sensor 20 is not particularly limited.

[0061] FIG. 7 is a cross-sectional view showing a state in which the cover member 300 is attached to the pulse wave sensor 20. FIG. 7 shows, as an example, a case in which the beam portion 22b and the extension portion 22d of the flexure body 22 are integral with each other, and the load portion 22c is provided at the center of the integral structure. As shown in FIG. 7, the cover member 300 has a gap 320 between it and the flexure body 22, and the surface (the side that contacts the subject's skin) has a substantially hemispherical shape. A convex portion 310 is provided at the center of the cover member 300, and the convex portion 310 and the load portion 22c are provided so as to face each other. In this embodiment, the load portion 22c is cylindrical, but for example, a curved surface protruding from the base portion 22a may be provided as the load portion 22c.

[0062] The convex portion 310 and the flexure body 22 (loading portion 22c in the case of FIG. 7) may be designed to be in contact with each other when no pressure is applied to the cover member 300, or may be designed to have a gap therebetween as shown in FIG. 7. That is, the convex portion 310 and the flexure body 22 or the loading portion 22c may be spaced apart when no pressure is applied. Regardless of the presence or absence of a gap, the convex portion 310 is designed to be in contact with the flexure body 22 (loading portion 22c in the case of FIG. 7) and transmit pressure when the cover member 300 is pressed against the body of the measurement subject. With such a design, the pressure applied to the cover member 300 can be concentrated on the portion of the flexure body 22 with which the convex portion 310 is in contact. Therefore, stress can be concentrated in a specific area of ​​the flexure body 22.

[0063] Moreover, by covering the flexure body 22 with the cover member 300, it is possible to prevent dirt, dust, and the like from entering the circular opening of the flexure body 22. Furthermore, even if the flexure body 22 is made of metal, it is possible to prevent the subject from having a metal allergy.

[0064] The shape of the cover member 300 is not particularly limited, but it is preferable to design it into a shape that applies pressure relatively evenly to the load portion 22c when the skin of the measurement object is pressed against the first surface 22m of the strain generator 22 at an angle other than perpendicular. Furthermore, it is preferable to design it so that the pressure propagating from the measurement object is applied relatively evenly to the cover member 300 even if the way in which the measurement object contacts the cover member 300 (i.e., the magnitude of the pressing force pressing the cover member 300 against the measurement object, which part of the cover member 300 is in contact with the measurement object, and the angle at which the cover member 300 is pressed against the measurement object) changes.

[0065] A preferred example of the above-mentioned "shape that allows pressure to be applied relatively evenly" is a hemispherical cover member 300 as shown in Fig. 7. In this manner, the upper surface of the cover member 300 can be a curved surface that is highest above the center of the first surface 22m of the flexure body 22, with the first surface 22m of the flexure body 22 as the reference point, and that becomes lower as it approaches the peripheral portion of the first surface 22m of the flexure body 22.

[0066] Other examples of the shape of the cover member 300 include shapes having a surface including a conic section, such as (A) a spheroid (semi-ellipsoid), (B) a super ellipsoid (oval ellipsoid), (C) an ovoid, and (D) a shape having a paraboloid of revolution, etc. For example, the surface of the cover member 300 on the measurement target side may be a surface including such a conic section.

[0067] The cover member 300 is not limited to the above (A) to (D), and may have a shape having a surface including a spline curve approximated to a rotation conic section (i.e., a spline surface), or a surface including a rotation conic section approximated by straight lines and curves. In a broader definition, the cover member 300 may have a shape such that a vertical line at an arbitrary point on the surface of the cover member 300 on the measurement target side intersects with a vertical line to the first surface 22m passing through the center of the first surface 22m of the strain body 22.

[0068] [Strain gauge 100] Fig. 8 is a plan view illustrating the strain gauge according to the first embodiment. Fig. 9 is a cross-sectional view (part 1) illustrating the strain gauge according to the first embodiment, showing a cross section along line BB in Fig. 8.

[0069] 8 and 9, the strain gauge 100 has a substrate 110, a resistor 130, wiring 140, electrodes 150, and a cover layer 160. That is, the strain gauge 100 has the resistor 130 as a detection element. The cover layer 160 can be provided as necessary. For convenience, only the outer edge of the cover layer 160 is shown by a dashed line in FIGS. 8 and 9. First, each part constituting the strain gauge 100 will be described in detail.

[0070] In the explanation of the strain gauge using Figs. 8 to 10, the definition of the upper surface and the lower surface is different from that in the other figures. Specifically, in Figs. 8 to 10, for convenience, in the strain gauge 100, the side of the substrate 110 on which the resistor 130 is provided is referred to as the "upper side", and the side on which the resistor 130 is not provided is referred to as the "lower side". Also, the surface located on the upper side of each part is referred to as the "upper surface", and the surface located on the lower side of each part is referred to as the "lower surface". However, the strain gauge 100 can also be used upside down. Also, the strain gauge 100 can be arranged at any angle. Also, the planar view refers to viewing the object in the normal direction from the upper side to the lower side with respect to the upper surface 110a of the substrate 110. And, the planar shape refers to the shape of the object when the object is viewed in the normal direction. The strain gauge 100 is attached to the second surface 22n of the flexure body 22 such that the base material 110 faces the second surface 22n of the flexure body 22.

[0071] The substrate 110 is a member that serves as a base layer for forming the resistor 130 and the like. The substrate 110 is flexible. The thickness of the substrate 110 is not particularly limited and may be appropriately determined depending on the intended use of the strain gauge 100 and the like. For example, the thickness of the substrate 110 may be about 5 μm to 500 μm. From the viewpoint of the transferability of strain from the second surface 22n of the strain generating body 22 to the sensing part and the dimensional stability against environmental changes, the thickness of the substrate 110 is preferably within the range of 5 μm to 200 μm. From the viewpoint of insulation, the thickness of the substrate 110 is preferably 10 μm or more.

[0072] The substrate 110 is formed from an insulating resin film such as, for example, PI (polyimide) resin, epoxy resin, PEEK (polyether ether ketone) resin, PEN (polyethylene naphthalate) resin, PET (polyethylene terephthalate) resin, PPS (polyphenylene sulfide) resin, LCP (liquid crystal polymer) resin, polyolefin resin, etc. The film refers to a member having a thickness of about 500 μm or less and having flexibility.

[0073] When the base material 110 is formed from an insulating resin film, the insulating resin film may contain a filler, impurities, etc. For example, the base material 110 may be formed from an insulating resin film containing a filler such as silica or alumina.

[0074] Examples of materials other than resin for the base material 110 include crystalline materials such as SiO2, ZrO2 (including YSZ), Si, Si2N3, Al2O3 (including sapphire), ZnO, and perovskite ceramics (CaTiO3, BaTiO3). In addition to the above-mentioned crystalline materials, amorphous glass or the like may be used as the material for the base material 110. Metals such as aluminum, aluminum alloy (duralumin), and titanium may also be used as the material for the base material 110. When a metal base material 110 is used, an insulating film is provided so as to cover the upper surface 110a.

[0075] The resistor 130 is a thin film formed in a predetermined pattern on the upper side of the substrate 110. In the strain gauge 100, the resistor 130 is a sensing part that receives strain and generates a resistance change. The resistor 130 may be formed directly on the upper surface 110a of the substrate 110, or may be formed on the upper surface 110a of the substrate 110 via another layer. For convenience, the resistor 130 is shown in FIG. 8 as having a dense matte pattern.

[0076] The resistor 130 has a structure in which multiple elongated parts are arranged at regular intervals with their longitudinal direction in the same direction (the direction of the line BB in the example of FIG. 8), and the ends of adjacent elongated parts are alternately connected, folding back in a zigzag pattern as a whole. The longitudinal direction of the multiple elongated parts is the grid direction, and the direction perpendicular to the grid direction is the grid width direction (the direction perpendicular to the line BB in the example of FIG. 8).

[0077] One end in the longitudinal direction of the two elongated portions located at the outermost sides in the grid width direction is bent in the grid width direction to form terminal ends 130e1 and 130e2 of the resistor 130 in the grid width direction. The terminal ends 130e1 and 130e2 of the resistor 130 in the grid width direction are electrically connected to the electrode 150 via the wiring 140. In other words, the wiring 140 electrically connects the terminal ends 130e1 and 130e2 of the resistor 130 in the grid width direction to the electrodes 150.

[0078] The resistor 130 can be formed, for example, from a material containing Cr (chromium), a material containing Ni (nickel), or a material containing both Cr and Ni. That is, the resistor 130 can be formed from a material containing at least one of Cr and Ni. An example of a material containing Cr is a Cr mixed phase film. An example of a material containing Ni is Cu-Ni (copper nickel). An example of a material containing both Cr and Ni is Ni-Cr (nickel chromium).

[0079] Here, the Cr mixed phase film is a film in which Cr, CrN, Cr2N, etc. are mixed. The Cr mixed phase film may contain inevitable impurities such as chromium oxide.

[0080] The thickness of the resistor 130 is not particularly limited and may be appropriately determined depending on the intended use of the strain gauge 100. For example, the thickness of the resistor 130 may be about 0.05 μm to 2 μm. In particular, when the thickness of the resistor 130 is 0.1 μm or more, the crystallinity of the crystals constituting the resistor 130 (for example, the crystallinity of α-Cr) is improved. Furthermore, when the thickness of the resistor 130 is 1 μm or less, (i) cracks in the film and (ii) warping of the film from the substrate 110 caused by the internal stress of the film constituting the resistor 130 are reduced.

[0081] Considering the need to prevent lateral sensitivity and to prevent disconnection, the width of resistor 130 is preferably 10 μm to 100 μm. More specifically, the width of resistor 130 is preferably 10 μm to 70 μm, and more preferably 10 μm to 50 μm.

[0082] For example, when the resistor 130 is a Cr mixed-phase film, the stability of the gauge characteristics can be improved by making α-Cr (alpha chromium) which is a stable crystal phase the main component. For example, when the resistor 130 is a Cr mixed-phase film, the resistor 130 can make α-Cr the main component, so that the gauge factor of the strain gauge 100 is 10 or more, and the gauge factor temperature coefficient TCS and the resistance temperature coefficient TCR can be in the range of -1000 ppm / °C to +1000 ppm / °C. Here, the "main component" means a component that occupies 50% by weight or more of the total material constituting the resistor. From the viewpoint of improving the gauge characteristics, the resistor 130 preferably contains 80% by weight or more of α-Cr. Furthermore, from the same viewpoint, the resistor 130 more preferably contains 90% by weight or more of α-Cr. Note that α-Cr is Cr with a bcc structure (body-centered cubic lattice structure).

[0083] In addition, when the resistor 130 is a Cr mixed-phase film, the Cr mixed-phase film preferably contains 20% by weight or less of CrN and Cr2N. By containing 20% ​​by weight or less of CrN and Cr2N in the Cr mixed-phase film, a decrease in the gauge factor of the strain gauge 100 can be suppressed.

[0084] In addition, the ratio of CrN and Cr2N in the Cr mixed phase film is preferably such that the ratio of Cr2N is 80% by weight or more and less than 90% by weight with respect to the total weight of CrN and Cr2N. More specifically, the ratio is more preferably such that the ratio of Cr2N is 90% by weight or more and less than 95% by weight with respect to the total weight of CrN and Cr2N. Cr2N has semiconductor properties. Therefore, by setting the ratio of Cr2N to 90% by weight or more and less than 95% by weight, the decrease in TCR (negative TCR) becomes more significant. Furthermore, by setting the ratio of Cr2N to 90% by weight or more and less than 95% by weight, the resistor 130 is less likely to become ceramic, and the resistor 130 is less likely to be brittle fractured.

[0085] On the other hand, CrN has the advantage of being chemically stable. By including more CrN in the Cr mixed-phase film, the possibility of unstable N being generated can be reduced, resulting in a stable strain gauge. Here, "unstable N" refers to trace amounts of N2 or atomic N that may be present in the Cr mixed-phase film. This unstable N may escape to the outside of the film depending on the external environment (e.g., high-temperature environment). When unstable N escapes to the outside of the film, the film stress of the Cr mixed-phase film may change.

[0086] In the strain gauge 100, when a Cr mixed-phase film is used as the material of the resistor 130, it is possible to realize high sensitivity and miniaturization. For example, while the output of a conventional strain gauge was about 0.04 mV / 2 V, when a Cr mixed-phase film is used as the material of the resistor 130, an output of 0.3 mV / 2 V or more can be obtained. In addition, while the size (gauge length x gauge width) of a conventional strain gauge was about 3 mm x 3 mm, when a Cr mixed-phase film is used as the material of the resistor 130, the size (gauge length x gauge width) can be miniaturized to about 0.3 mm x 0.3 mm.

[0087] The wiring 140 is provided on the substrate 110. The wiring 140 is electrically connected to the resistor 130 and the electrode 150. The wiring 140 is not limited to being linear, and may be in any pattern. The wiring 140 may have any width and any length. For convenience, the wiring 140 is shown in FIG. 8 as having a matte pattern with a lower density than the resistor 130.

[0088] The electrodes 150 are provided on the substrate 110. The electrodes 150 are electrically connected to the resistor 130 via the wiring 140. The electrodes 150 are formed in a substantially rectangular shape wider than the wiring 140 in a plan view. The electrodes 150 are a pair of electrodes for outputting a change in the resistance value of the resistor 130 caused by distortion to the outside. For example, a lead wire for external connection is joined to the electrodes 150. A metal layer having low resistance such as copper or a metal layer having good solderability such as gold may be laminated on the upper surface of the electrode 150. Although the resistor 130, the wiring 140, and the electrode 150 are denoted by different reference numerals for convenience, they can be integrally formed from the same material in the same process. In FIG. 8, the electrodes 150 are shown with a matte pattern having the same density as the wiring 140 for convenience.

[0089] The cover layer 160 (protective layer) is provided on the upper surface 110a of the base material 110 as necessary so as to cover the resistor 130 and the wiring 140 and expose the electrodes 150. Examples of materials for the cover layer 160 include insulating resins such as PI resin, epoxy resin, PEEK resin, PEN resin, PET resin, PPS resin, and composite resins (e.g., silicone resin, polyolefin resin). The cover layer 160 may contain a filler or a pigment. The thickness of the cover layer 160 is not particularly limited and can be appropriately selected depending on the purpose. For example, the thickness of the cover layer 160 can be about 2 μm to 30 μm. By providing the cover layer 160, it is possible to suppress mechanical damage and the like from occurring in the resistor 130. In addition, by providing the cover layer 160, it is possible to protect the resistor 130 from moisture and the like.

[0090] [Manufacturing method of strain gauge 100] In the strain gauge 100 according to this embodiment, a resistor 130, wiring 140, electrodes 150, and a cover layer 160 are formed on a substrate 110. Note that another layer (such as a functional layer described below) may be formed between the substrate 110 and the layers of these members.

[0091] A method for manufacturing the strain gauge 100 will be described below. To manufacture the strain gauge 100, first, a base material 110 is prepared, and a metal layer (for convenience, referred to as metal layer A) is formed on an upper surface 110a of the base material 110. The metal layer A is a layer that is finally patterned to become the resistor 130, the wiring 140, and the electrodes 150. Therefore, the material and thickness of the metal layer A are the same as the material and thickness of the resistor 130, the wiring 140, and the electrodes 150 described above.

[0092] The metal layer A can be formed by, for example, magnetron sputtering using a target made of a raw material capable of forming the metal layer A. Instead of magnetron sputtering, the metal layer A may be formed by reactive sputtering, vapor deposition, arc ion plating, pulsed laser deposition, or the like. After the metal layer A is formed on the upper surface 110a of the base material 110, the metal layer A is patterned by a well-known photolithography method into a planar shape similar to that of the resistor 130, the wiring 140, and the electrode 150 in FIG. 8.

[0093] Alternatively, a base layer may be formed on the upper surface 110a of the base material 110, and then the metal layer A may be formed. For example, a functional layer of a predetermined thickness may be vacuum-formed by conventional sputtering on the upper surface 110a of the base material 110. By providing a base layer in this manner, the gauge characteristics of the strain gauge 100 can be stabilized.

[0094] In the present application, the functional layer refers to a layer having a function of promoting the crystal growth of at least the upper layer, metal layer A (resistor 130). The functional layer preferably further has a function of preventing oxidation of metal layer A due to oxygen or moisture contained in base material 110, and / or a function of improving adhesion between base material 110 and metal layer A. The functional layer may further have other functions.

[0095] The insulating resin film constituting the base material 110 may contain oxygen or moisture, and Cr may form a self-oxidized film. Therefore, particularly when the metal layer A contains Cr, it is preferable to form a functional layer having a function of preventing the oxidation of the metal layer A.

[0096] In this way, by providing a functional layer below the metal layer A, it is possible to promote crystal growth of the metal layer A, and to fabricate a metal layer A consisting of a stable crystal phase. As a result, the stability of the gauge characteristics of the strain gauge 100 is improved. In addition, the material constituting the functional layer diffuses into the metal layer A, thereby improving the gauge characteristics of the strain gauge 100.

[0097] Examples of materials for the functional layer include one or more metals selected from the group consisting of Cr (chromium), Ti (titanium), V (vanadium), Nb (niobium), Ta (tantalum), Ni (nickel), Y (yttrium), Zr (zirconium), Hf (hafnium), Si (silicon), C (carbon), Zn (zinc), Cu (copper), Bi (bismuth), Fe (iron), Mo (molybdenum), W (tungsten), Ru (ruthenium), Rh (rhodium), Re (rhenium), Os (osmium), Ir (iridium), Pt (platinum), Pd (palladium), Ag (silver), Au (gold), Co (cobalt), Mn (manganese), and Al (aluminum), an alloy of any of the metals in this group, or a compound of any of the metals in this group.

[0098] 10 is a cross-sectional view (part 2) illustrating the strain gauge according to the first embodiment. Fig. 10 shows the cross-sectional shape of the strain gauge 100 when a functional layer 120 is provided as an underlying layer for the resistor 130, the wiring 140, and the electrodes 150.

[0099] The planar shape of the functional layer 120 may be patterned to be substantially the same as the planar shapes of the resistor 130, the wiring 140, and the electrode 150, for example. However, the planar shapes of the functional layer 120, the resistor 130, the wiring 140, and the electrode 150 may not be substantially the same. For example, when the functional layer 120 is formed from an insulating material, the functional layer 120 may be patterned to be different from the planar shapes of the resistor 130, the wiring 140, and the electrode 150. In this case, the functional layer 120 may be formed in a solid shape in the region where the resistor 130, the wiring 140, and the electrode 150 are formed, for example. Alternatively, the functional layer 120 may be formed in a solid shape on the entire upper surface of the substrate 110.

[0100] After forming the resistor 130, the wiring 140, and the electrodes 150, a cover layer 160 is formed on the upper surface 110a of the base material 110 as necessary. The cover layer 160 covers the resistor 130 and the wiring 140, but the electrodes 150 may be exposed from the cover layer 160. For example, the cover layer 160 can be formed by laminating a semi-cured thermosetting insulating resin film on the upper surface 110a of the base material 110 so as to cover the resistor 130 and the wiring 140 and expose the electrodes 150, and then heating and curing the insulating resin film. Through the above steps, the strain gauge 100 is completed.

[0101] In the first embodiment, an example using a pulse wave sensor 20 having a strain gauge has been described. However, the pulse wave sensor 20 is not limited to a configuration having a pressure element such as a strain gauge, and may be, for example, an optical type. An optical pulse wave sensor is a sensor that irradiates light of a predetermined wavelength from a light source toward a living body, receives the light that passes through the living body or the light reflected by the living body with a light receiving element, and measures a pulse wave based on the amount of light received. In an optical pulse wave sensor, the output of the light receiving element is converted into a voltage signal to become the output signal S1. When an optical pulse wave sensor is used in the pulse wave measuring device 1, the same effect as when a pulse wave sensor 20 having a strain gauge is used is achieved.

[0102] First Modification of the First Embodiment In Modification 1 of the first embodiment, an example of a pulse wave measuring device in which the shape of the cover member is different from that of the first embodiment is shown. In the various modifications described below, including this modification, the same components as those in the already described embodiment are given the same reference numerals, and the description thereof may be omitted.

[0103] FIG. 11 is a diagram showing the pulse wave sensor 20 according to this modification. The cover member 330 shown in FIG. 11 is different from the cover member 300 of the first embodiment in that there is no clearly protruding portion such as the convex portion 310 on the surface facing the flexure body 22. The other points of the cover member 330 may be the same as the cover member 300, or may be modified in the same manner as the cover member 300. In the cover member 330 according to this modification, at least a part of the surface facing the flexure body 22 is a curved surface that is curved toward the flexure body 22. In the pulse wave sensor 20 according to this modification, this entire curved surface of the cover member 330 acts as a convex portion. In the example of FIG. 11, the cover member 330 has a curved surface in which the center part of the surface facing the flexure body 22 is gently inclined toward the flexure body 22. With such a design, the pressure applied to the cover member 330 can be concentrated at the portion where the cover member 330 and the flexure body 22 come into contact (for example, the load point of the flexure body 22). Therefore, the cover member 330 allows the pulse wave sensor 20 to concentrate stress in a specific area of ​​the flexure body 22. As with the cover member 300, the use of the cover member 330 can prevent the intrusion of dirt, dust, and the like through the circular opening of the flexure body 22. Furthermore, even if the flexure body 22 is made of metal, it is possible to prevent the subject from having a metal allergy.

[0104] Like the cover member 300, the shape of the cover member 330 is not limited to a hemisphere. For example, as described in the description of the cover member 300, the cover member 330 may have a shape having a surface including a rotational conic section, a shape having a spline surface, or a shape having a surface in which a surface including a rotational conic section is approximated by straight lines and curves.

[0105] Second Modification of the First Embodiment In the second modification of the first embodiment, an example of a pulse wave measuring device having a housing shape different from that of the first embodiment is shown. Fig. 12 is a view of the pulse wave measuring device according to the second modification of the first embodiment as viewed from the side indicated by the arrow P in Fig. 1. Fig. 13 is a view of the pulse wave measuring device according to the second modification of the first embodiment as viewed from the side indicated by the arrow Q in Fig. 1. In Figs. 12 and 13, the amplifier 30 and the information processing device 50 are omitted from illustration.

[0106] As shown in Fig. 12 and Fig. 13, the housing 10 and the finger insertion section 10x may be sized and configured so that they can be worn by a plurality of fingers. In the example of Fig. 12 and Fig. 13, the finger insertion section 10x of the housing 10 is sized so that it can be worn by two fingers, but it may be sized so that it can be worn by three or more fingers. In this case, the same effect as in the first embodiment is obtained. The second modification of the first embodiment has the advantage that even a relatively large pulse wave sensor 20 can be attached to the housing 10.

[0107] <Modification 3 of the First Embodiment> Fig. 14 is a view of a pulse wave measuring device according to a third modification of the first embodiment, as viewed from the side indicated by arrow P in Fig. 1. Fig. 15 is a view of a pulse wave measuring device according to a third modification of the first embodiment, as viewed from the side indicated by arrow Q in Fig. 1. Amplifier 30 and information processing device 50 are omitted from Figs. 14 and 15.

[0108] As shown in Fig. 14 and Fig. 15, the pulse wave measuring device according to this modification may include a plurality of housings each having a finger insertion section 10x. In the example of Fig. 14 and Fig. 15, the pulse wave measuring device has two housings (housings 10A and 10B) so that it can be worn on two fingers, respectively, and each housing is provided with a finger insertion section 10x. The pulse wave measuring device according to this modification may have three or more housings. For example, the pulse wave measuring device may have three housings each having a finger insertion section 10x so that it can be worn on the index finger, middle finger, and ring finger, respectively.

[0109] One pulse wave sensor 20 is provided for each housing. Meanwhile, one output device 40 may be provided for each housing, or one (or several) output devices 40 may be provided for a plurality of housings together. Specifically, when the output device 40 is an earphone or a headphone, a predetermined number of output devices 40 may be provided for all housings together (i.e., for the entire pulse wave measuring device 1). When the output device 40 is a vibration device, one output device 40 may be provided for each housing (i.e., for each finger).

[0110] When each housing has one pulse wave sensor 20 and one output device 40, the amplifier 30 may combine and then amplify the multiple output signals S1 input from each pulse wave sensor 20, or may amplify each of the multiple output signals S1 separately without combining them. When amplifying the multiple output signals S1 separately, the amplifier 30 may output each amplified signal S2 to the output device 40 provided in the same housing as the pulse wave sensor 20 that output the unamplified output signal S1. This configuration has the advantage that the user can recognize to what extent the pulse wave of the subject is being captured by the pulse wave sensor 20 corresponding to each finger.

[0111] The preferred embodiments and the like have been described above in detail. However, the pulse wave measuring device according to the present disclosure is not limited to the above-described embodiments and modifications. For example, various modifications and substitutions can be made to the pulse wave measuring device according to the above-described embodiments and the like without departing from the scope of the claims. [Explanation of symbols]

[0112] 1 Pulse wave measuring device, 10, 10A housing, 10x finger insertion portion, 20 pulse wave sensor, 30 amplifier, 40 output device, 50 information processing device, 22 strain body, 22m first surface, 22n second surface, 22a base portion, 22b beam portion, 22c load portion, 22d extension portion, 23 wire, 1001, 1002, 1003, 1004 strain gauge, 110 substrate, 110a upper surface, 130 resistor, 140 wiring, 150 electrode, 160 cover layer, 130e1, 130e2 termination, 300, 330 cover member, 310 convex portion, 320 gap

Claims

1. A housing that can be worn on a finger; A pulse wave sensor fixed to a portion of the housing that is located on the palm side of the finger; an amplifier that receives an output signal from the pulse wave sensor and amplifies the output signal to output an amplified signal; and an output device that receives the amplified signal and operates in response to the amplified signal.

2. The pulse wave measuring device according to claim 1 , wherein the output device operates in a manner linked to at least one of the presence or absence of output of the amplified signal, the magnitude of the output, the amplitude of the output, and the output waveform.

3. The pulse wave measuring device according to claim 1 , wherein the output device is a vibration device.

4. the vibration device is fixed to a portion of the housing that is located on the palm side of the finger, The pulse wave measuring device according to claim 3 , wherein the pulse wave sensor is fixed to the housing via the vibration device.

5. The pulse wave measuring device according to claim 3 , wherein the vibration device is fixed to a portion of the housing that is located on a side of the fingernail.

6. A plurality of the housings are provided which can be worn on a plurality of fingers, the pulse wave sensor and the output device are provided for each of the plurality of housings, The amplifier comprises: The output signals input from each pulse wave sensor are amplified separately.

6. The pulse wave measuring device according to claim 1, wherein each amplified signal is output to an output device provided in the same housing as the pulse wave sensor that outputs the unamplified output signal.

7. The pulse wave sensor includes a plurality of strain gauges. The pulse wave measuring device according to claim 1 , wherein the output signal is generated based on outputs from a plurality of the strain gauges.

8. The pulse wave sensor has a strain generating body, The plurality of strain gauges include a pair of strain gauges provided on the strain body and configured to detect a compressive strain of the strain body; Another pair of strain gauges are provided on the strain body to detect the tensile strain of the strain body; Including, a pair of the strain gauges and another pair of the strain gauges are connected to form each side of a bridge circuit; The pulse wave measuring device according to claim 7 , wherein the output signal is generated by the bridge circuit.

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