Pulse wave measuring device

Abstract

To provide a pulse wave measuring device with a structure in which a pulse wave sensor is hardly inclined with respect to the radial artery of a subject.SOLUTION: A pulse wave measuring device includes a sensor part including a pulse wave sensor and a mounting part connected to the outside of the sensor part, which can be mounted on a subject. The mounting part includes a first curved member and a second curved member that are curved in the opposite directions and opposed to each other so as to be mounted on the wrist of the subject, and can transition between a closed state and an open state. The sensor part is arranged on one end side in a longitudinal direction of the first curved member. The second curved member includes a region whose width in a lateral direction is narrower than the width in a lateral direction of the first curved member. The second curved member is of an asymmetrical shape with respect to a virtual line that divides a maximum width part in the lateral direction in two and extends in the longitudinal direction.SELECTED DRAWING: Figure 5

Description

[Technical field]

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

[0002] There is known a pulse wave measuring device that includes a pulse wave sensor that detects a pulse wave generated when the heart pumps blood. Such a pulse wave measuring device is configured to be worn on the wrist of a subject, for example (see Patent Document 1, for example). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5094131 Summary of the Invention [Problem to be solved by the invention]

[0004] Since the pulse wave sensor needs to detect minute signals, it is preferable to place it horizontally with respect to the subject's radial artery in order to improve measurement accuracy.

[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 having a structure in which the pulse wave sensor is less likely to be tilted with respect to the subject's radial artery. [Means for solving the problem]

[0006] A pulse wave measuring device according to one embodiment of the present disclosure has a sensor unit including a pulse wave sensor, and a wearing unit connected to the outside of the sensor unit and wearable by a subject, the wearing unit having a first curved member and a second curved member that are curved in opposite directions and face each other so that the wearing unit can be worn on the wrist of the subject, and that can transition between a closed state and an open state, the sensor unit is disposed on one end side of the first curved member in the longitudinal direction, the second curved member has an area whose width in the lateral direction is narrower than the width of the first curved member in the lateral direction, and the second curved member has an asymmetric shape with respect to a virtual line that bisects the maximum width portion in the lateral direction and extends in the longitudinal direction. Effect of the Invention

[0007] According to the disclosed technique, it is possible to provide a pulse wave measuring device having a structure in which the pulse wave sensor is less likely to be tilted with respect to the subject's radial artery. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view (part 1) illustrating a pulse wave measuring device according to a first embodiment. [Diagram 2] FIG. 2 is a perspective view (part 2) illustrating the pulse wave measuring device according to the first embodiment. [Diagram 3] 1 is a side view illustrating a pulse wave measuring device according to a first embodiment. [Figure 4] 1 is a front view illustrating a pulse wave measuring device according to a first embodiment. [Diagram 5] 1 is a bottom view illustrating a pulse wave measuring device according to a first embodiment. FIG. [Figure 6] 1 is an example of a pulse wave. [Figure 7] FIG. 4 is a perspective view illustrating a first bending member. [Figure 8] FIG. 2 is an exploded perspective view illustrating a movable portion. [Figure 9] FIG. 2 is an exploded perspective view illustrating a fixed portion and a movable portion. [Figure 10] FIG. 2 is an exploded perspective view illustrating a sensor unit. [Figure 11] FIG. 4 is a cross-sectional view illustrating a sensor unit. [Figure 12] FIG. 1 is a cross-sectional view (part 1) illustrating a pivot portion. [Figure 13] FIG. 2 is a cross-sectional view (part 2) illustrating the pivot portion. [Figure 14] 1 is a plan view illustrating a pulse wave sensor according to a first embodiment. [Figure 15] 1 is a cross-sectional view illustrating a pulse wave sensor according to a first embodiment. [Figure 16] This is an example of a bridge circuit. [Figure 17] FIG. 2 is a plan view illustrating the strain gauge according to the first embodiment. [Figure 18] 1 is a cross-sectional view (part 1) illustrating a strain gauge according to a first embodiment. FIG. [Figure 19] 4 is a cross-sectional view (part 2) illustrating the strain gauge according to the first embodiment. FIG. [Figure 20] FIG. 1 is a first diagram for explaining a biasing member. [Figure 21] FIG. 2 is a second diagram for explaining the biasing member. [Figure 22] 1 is a cross-sectional view (part 1) showing a state in which a cover member is attached to a pulse wave sensor. FIG. [Diagram 23] 13 is a second cross-sectional view showing a state in which a cover member is attached to the pulse wave sensor. 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 1] Fig. 1 is a perspective view (part 1) illustrating the pulse wave measuring device according to the first embodiment, and shows a schematic diagram of the pulse wave measuring device worn on the wrist of a subject. Fig. 2 is a perspective view (part 2) illustrating the pulse wave measuring device according to the first embodiment. Fig. 3 is a side view illustrating the pulse wave measuring device according to the first embodiment.

[0011] 1 to 3, a pulse wave measuring device 1 is a wearable device that can be worn by a subject, and has a sensor section 10 and a wearing section 80 as main components.

[0012] 1, pulse wave measuring device 1 is attached to the wrist of a subject by attachment part 80 so that pulse wave sensor 20 (described later) having strain body 22 contacts skin 310 above radial artery 300 of the subject. A pulse wave is a waveform representing changes in the volume of blood vessels that occur as the heart pumps blood, and pulse wave measuring device 1 can monitor changes in the volume of blood vessels.

[0013] The sensor unit 10 includes a pulse wave sensor that detects the pulse wave of the subject. The sensor unit 10 includes a movable part 30, a fixed part 40, a connecting part 50, and a rotating part 60. The sensor unit 10 will be described in detail later.

[0014] The mounting unit 80 is connected to the outside of the sensor unit 10 and can be worn by the subject. The mounting unit 80 has a first curved member 81 and a second curved member 82 that are curved in opposite directions and face each other so that it can be worn on the wrist of the subject. A lid portion 83 is provided on the first curved member 81. The first curved member 81, the second curved member 82, and the lid portion 83 can be formed from, for example, resin or the like.

[0015] The first curved member 81 and the second curved member 82 are biased by biasing members 84 and 85 bent into a substantially V-shape, and are supported by a swing shaft 86 so as to be transitionable between a closed state and an open state. In the illustrated example, one end of the biasing members 84 and 85 is attached to a spring attachment portion 83x provided on the cover portion 83, and the other end is attached to a spring attachment portion 82x provided on the second curved member 82. The biasing members 84 and 85 can be made of, for example, a metal or the like. The biasing members 84 and 85 are, for example, torsion springs, but may also be leaf springs or the like.

[0016] The sensor unit 10 is disposed at one end side in the longitudinal direction of the first bending member 81, and the oscillating shaft 86 is disposed at the other end side in the longitudinal direction of the first bending member 81. The sensor unit 10 is attached to the first bending member 81 by, for example, a screw or the like. The oscillating shaft 86 may be formed integrally with the first bending member 81, or may be a separate piece joined thereto.

[0017] A first operating unit 87 is provided on the opposite side of the sensor unit 10 across the swing shaft 86 of the first bending member 81. A second operating unit 88 is provided on the opposite side of the sensor unit 10 across the swing shaft 86 of the second bending member 82. The first operating unit 87 and the second operating unit 88 can be made of, for example, resin or the like. The first operating unit 87 may be formed integrally with the first bending member 81, or may be a separate piece joined thereto. The second operating unit 88 may be formed integrally with the second bending member 82, or may be a separate piece joined thereto.

[0018] When putting the pulse wave measuring device 1 on the subject, the subject or an assistant assisting the subject pinches the first operating unit 87 and the second operating unit 88 and brings them close to each other. This opens the sensor unit 10 sides of the first bending member 81 and the second bending member 82, allowing the pulse wave measuring device 1 to be put on the subject.

[0019] Fig. 4 is a front view illustrating the pulse wave measuring device according to the first embodiment. Fig. 5 is a bottom view illustrating the pulse wave measuring device according to the first embodiment. In Figs. 4 and 5, Q indicates the short side direction of the first bending member 81 and the second bending member 82. In Fig. 5, P indicates the long side direction of the first bending member 81 and the second bending member 82.

[0020] 4 and 5, the second curved member 82 has a region E in which a width W1 in the short side direction Q is narrower than a width W2 in the short side direction Q of the first curved member 81. The second curved member 82 has an asymmetric shape with respect to an imaginary line L that halves the maximum width portion in the short side direction Q and extends in the longitudinal direction P. The widths W1 and W2 are constant, for example.

[0021] On the side farther from the sensor unit 10 than the region E in the longitudinal direction P of the second bending member 82, the width W3 in the short side direction Q of the second bending member 82 may be the same as the width W2 in the short side direction Q of the first bending member 81, for example. In this case, the first bending member 81 and the second bending member 82 can be securely attached to the wrist of the subject.

[0022] The second bending member 82 is preferably provided with a notch 82z extending from one end side in the short side direction Q of the second bending member 82 toward the imaginary line L. In this case, the region E is adjacent to the notch 82z in the short side direction Q of the second bending member 82. When the second bending member 82 is provided with the notch 82z, it is easy to provide the second bending member 82 with a region E having a narrow width in the short side direction Q. When the notch 82z is not provided, for example, two members having different widths in the short side direction Q can be joined in the longitudinal direction to form the second bending member 82 having the region E.

[0023] Let us assume that in the pulse wave measuring device 1, the second curved member 82 does not have an area E whose width in the short side direction is narrower than the width in the short side direction of the first curved member 81. In this case, when measuring a pulse wave with the pulse wave measuring device 1, if the subject's hand is bent in the direction shown in FIG. 1, the back of the hand will touch the second curved member 82, causing the sensor unit 10 to tilt. As a result, the strain generating body 22 of the pulse wave sensor 20 will no longer be able to maintain its horizontal position relative to the radial artery and will tilt, and may even be displaced from above the radial artery. As a result, the pulse wave measuring device 1 cannot accurately measure the pulse wave.

[0024] However, in the pulse wave measuring device 1, the second curved member 82 has an area E whose width in the short side direction is narrower than the width in the short side direction of the first curved member 81. The pulse wave measuring device 1 is worn on the wrist of the subject so that the side where the notch portion 82z is provided is the hand side. In this case, when measuring the pulse wave with the pulse wave measuring device 1, even if the subject's hand is bent in the direction shown in FIG. 1, the back side of the hand is unlikely to come into contact with the second curved member 82, and the sensor unit 10 is not tilted. Therefore, the strain generating body 22 (described later) of the pulse wave sensor 20 can be kept horizontal with respect to the radial artery, and is not displaced from above the radial artery. As a result, the pulse wave measuring device 1 can accurately measure the pulse wave.

[0025] The notch 82z is preferably located on the side closer to the sensor unit 10 in the longitudinal direction P of the second bending member 82. If the notch 82z is located in such a position, even if the subject's hand is bent in the direction shown in FIG. 1, the back of the subject's hand is less likely to touch the second bending member 82, making it easier for the strain body 22 to maintain the horizontal position with respect to the radial artery.

[0026] 5, in bottom view, the center O of the sensor unit 10 is preferably located closer to the cutout portion 82z than the imaginary line L in the short-side direction Q of the second curved member 82. This makes it easier for the strain body 22 to maintain its horizontal position with respect to the radial artery even if the subject's hand is bent in the direction shown in FIG.

[0027] The width W1 of the second bending member 82 in the short-side direction Q is, for example, 35 mm, and the width W2 of the first bending member 81 in the short-side direction Q is, for example, 45 mm. In this case, the width of the cutout portion 82z in the short-side direction Q is 10 mm. The length of the cutout portion 82z in the longitudinal direction P is, for example, 90 mm. Note that these dimensions are merely examples and are not limited to these.

[0028] Figure 6 is an example of a pulse wave. In Figure 6, the vertical axis indicates blood pressure, and the horizontal axis indicates the time elapsed since the minimum value of the pulse wave. In Figure 6, A indicates the ejection wave caused by the ejection of blood from the heart, B indicates the ebb wave which is a reflected wave from the arterial bifurcation, C indicates the notch caused by the closure of the aortic valve, and D indicates the dicrotic wave. Also, ΔBP is the pulse pressure.

[0029] The tidal wave is generated by the reflection of the ejection wave at peripheral arteries and arterial bifurcations as it spreads throughout the body. If the subject's hand is bent in the direction shown in Figure 1 and the flexure body 22 cannot maintain a horizontal position relative to the radial artery, the tidal wave will have an earlier peak than when the flexure body 22 can maintain a horizontal position relative to the radial artery. This will result in an error in the measurement of the pulse wave.

[0030] By using pulse wave measuring device 1, even if the subject's hand is bent in the direction shown in FIG. 1, strain body 22 can be maintained horizontally relative to the radial artery, so that the peak of the tidal wave can be accurately measured.

[0031] Fig. 7 is a perspective view for explaining the first curved member, and shows a state in which the cover 83 is removed from the pulse wave measuring device 1. As shown in Fig. 7, the first curved member 81 may have a wiring board 90 arranged between one end side and the other end side in the longitudinal direction. The wiring board 90 can be arranged in the gap between the first curved member 81 and the cover 83. The wiring board 90 is electrically connected to the pulse wave sensor 20 (described later).

[0032] For example, components that contribute to detecting a pulse wave are arranged on the wiring board 90. Examples of the components include an amplifier circuit that amplifies the output of the strain gauge 100, an AD converter that converts the output of the amplifier circuit into a digital signal, a semiconductor for signal processing that processes the digital signal, and a semiconductor for wireless communication that transmits the result of the signal processing to the outside. A cable 95 may be connected to the wiring board 90. The cable 95 can be used for supplying power and inputting and outputting electrical signals to and from an external circuit.

[0033] Fig. 8 is an exploded perspective view illustrating the movable part. As shown in Fig. 8, the movable part 30 has the pulse wave sensor 20, a sensor holding part 31, a lid part 32, and a male screw part 33. The sensor holding part 31, the lid part 32, and the male screw part 33 can be formed from, for example, metal, resin, or the like.

[0034] The pulse wave sensor 20 includes, for example, a housing 21, a strain generating body 22 provided on one side of the housing 21, and an opposing part 23 provided on the other side of the housing 21. The housing 21 is, for example, a cylindrical member with both ends open. The housing 21 can be formed from, for example, metal, resin, or the like.

[0035] The flexure body 22 is substantially disk-shaped and is fixed to the housing 21 with an adhesive or the like so as to cover one side of the housing 21. As described later, the flexure body 22 is a portion where, for example, a strain gauge is disposed and which detects a pulse wave. A detailed example of the structure of the pulse wave sensor 20 including the flexure body 22 will be described later.

[0036] The facing portion 23 is substantially disk-shaped and is fixed to the housing 21 so as to close the other side of the housing 21. The facing portion 23 has, for example, a through hole 23x and is screwed into a groove 21x provided in the housing 21 by a screw 24 inserted into the through hole 23x. The facing portion 23 faces the flexure body 22 across the space inside the housing 21. The mutually facing surfaces of the facing portion 23 and the flexure body 22 are, for example, parallel to each other.

[0037] The facing portion 23 has a first surface 23a which is the surface opposite to the surface facing the flexure body 22. The first surface 23a of the facing portion 23 is, for example, a flat surface. A pivot portion 23p which protrudes to the opposite side to the flexure body 22 is provided at approximately the center of the first surface 23a of the facing portion 23. The pivot portion 23p is, for example, a substantially cylindrical member. The central axis of the pivot portion 23p is, for example, perpendicular to the first surface 23a of the facing portion 23.

[0038] The facing portion 23 has, for example, a flange portion 23f that protrudes from the outer surface of the housing 21 to the outside in the radial direction of the housing 21. The flange portion 23f is, for example, ring-shaped. The facing portion 23 may have one or more notches 23y that can be used for preventing rotation, etc. The notches 23y are recessed, for example, from the outer periphery side of the facing portion 23 toward the center side.

[0039] The facing portion 23 can be made of, for example, metal, resin, etc. The pivot portion 23p may be formed integrally with other portions of the facing portion 23, or may be a separate piece joined to the pivot portion 23p.

[0040] Pulse wave sensor 20 has wire 25 for inputting and outputting electrical signals between the inside and outside of housing 21. A plurality of wires insulated from each other may be arranged inside wire 25. One end of each of the plurality of wires is electrically connected to an electrode of a strain gauge, which will be described later. Pulse wave sensor 20 may have a flexible substrate or the like instead of wire 25.

[0041] Alternatively, one or more wiring boards 26 may be fixed to the inner surface of the housing 21, and a pair of electrodes of the strain gauge may be electrically connected to the wiring boards 26 with thin wires. The wiring boards 26 may then be electrically connected to the wires 25. With this structure, the force from the wires 25 is less likely to be transmitted to the strain generating body 22, improving the accuracy of detecting the pulse wave.

[0042] The sensor holding portion 31 is, for example, a cylindrical member with both ends open. The inner surface of the sensor holding portion 31 has, for example, a stepped surface 31a that protrudes toward the central axis (the center side of the sensor unit 10). The stepped surface 31a is, for example, perpendicular to the axial direction of the sensor holding portion 31. The stepped surface 31a is, for example, ring-shaped.

[0043] The sensor holding portion 31 has a positioning portion 31b that is provided above the step surface 31a and protrudes from the inner surface toward the central axis. In the illustrated example, two positioning portions 31b are provided to face each other. Each positioning portion 31b is provided with a groove 31x. Note that there may be one or more positioning portions 31b.

[0044] Pulse wave sensor 20 is held inside sensor holding part 31 with cutout portion 23y aligned with positioning portion 31b, and is prevented from rotating relative to sensor holding part 31. However, pulse wave sensor 20 is not fixed to sensor holding part 31, and has a gap that allows it to move relative to sensor holding part 31. When pulse wave measuring device 1 is not worn by a subject, flange portion 23f contacts step surface 31a.

[0045] The sensor holding portion 31 has a groove 31y recessed from the outer surface toward the center. The groove 31y is elongated with the axial direction of the sensor holding portion 31 as the longitudinal direction. The groove 31y is provided so as to reach the lower end but not to reach the upper end of the outer surface of the sensor holding portion 31. For example, two grooves 31y can be arranged so as to face each other across the center of the sensor holding portion 31 in a plan view. It is sufficient that there is one or more grooves 31y.

[0046] The lid portion 32 has a through hole 32x. The lid portion 32 is fixed to the other axial end side of the sensor holding portion 31 by, for example, screwing a screw 34 inserted through the through hole 32x into a groove 31x provided in the positioning portion 31b. The male thread portion 33 is provided in the center of the upper surface of the lid portion 32 and protrudes from the upper surface of the lid portion 32 in the opposite direction to the strain body 22. The male thread portion 33 may be formed integrally with the lid portion 32, or may be a separate body joined thereto.

[0047] In this manner, the pulse wave sensor 20 is held inside the sensor holding part 31 such that the strain generator 22 is exposed from one axial end side of the sensor holding part 31. The cover part 32 is fixed to the other axial end side of the sensor holding part 31.

[0048] 9 is an exploded perspective view illustrating the fixed part and the movable part, in which the fixed part 40 is shown in two views from different directions for the sake of convenience.

[0049] The fixing portion 40 has a tubular portion 41 and a flange portion 42. The tubular portion 41 is, for example, a cylindrical member with both ends open. The flange portion 42 is a member that protrudes from at least a part of the outer surface of the tubular portion 41 to the outside in the radial direction of the tubular portion 41. The flange portion 42 may have a notch portion. The fixing portion 40 can be formed from, for example, metal, resin, etc. The flange portion 42 may be formed integrally with the tubular portion 41, or may be a separate member joined thereto.

[0050] The cylindrical portion 41 has, for example, a step surface 41a protruding toward the central axis (the center side of the cylindrical portion 41). The step surface 41a is, for example, perpendicular to the axial direction of the cylindrical portion 41. The step surface 41a is, for example, ring-shaped. The cylindrical portion 41 has two protruding portions 41c protruding toward the central axis from the inner surface 41b. The protruding portions 41c are, for example, cylindrical. For example, two protruding portions 41c can be arranged to face each other across the center of the cylindrical portion 41 in a plan view. It is sufficient that there is one or more protruding portions 41c.

[0051] The cylindrical portion 41 has a through hole 41x penetrating from the outer surface to the inner surface. For example, two through holes 41x can be arranged to face each other across the center of the cylindrical portion 41 in a plan view. The cylindrical portion 41 may have a cutout portion 41y for passing the wire 25 through. The flange portion 42 has a through hole 42x. For example, four through holes 42x can be arranged at positions symmetrically across the center of the cylindrical portion 41 in a plan view.

[0052] The movable part 30 is accommodated inside the cylindrical part 41 of the fixed part 40 so that the two grooves 31y fit into the two protruding parts 41c. The movable part 30 is movable in the axial direction of the cylindrical part 41. The movable part 30 hardly moves in the circumferential direction of the cylindrical part 41 because the protruding parts 41c fit into the grooves 31y. In other words, the protruding parts 41c fit into the grooves 31y, and the sensor holding part 31 is prevented from rotating with respect to the cylindrical part 41. In addition, the downward movement range of the movable part 30 is restricted to the range in which the protruding parts 41c can fit into the grooves 31y, that is, the range of the longitudinal length of the grooves 31y.

[0053] Fig. 10 is an exploded perspective view illustrating the sensor unit. As shown in Fig. 10, the sensor unit 10 has a movable unit 30, a fixed unit 40, a connecting unit 50, and a rotating unit 60. The connecting unit 50 and the rotating unit 60 can be made of, for example, metal or resin. In Fig. 10, the first disk unit 61 is shown in two views viewed from different directions for convenience.

[0054] The rotating part 60 closes one opening of the cylindrical part 41, and rotates relative to the fixed part 40 about the central axis of the cylindrical part 41 as the axis of rotation. The strain element 22 is exposed from the other opening of the cylindrical part 41.

[0055] The rotating part 60 has a first disk part 61 having a female thread part 61x at the center protruding toward the strain body 22, and a second disk part 62 having a smaller diameter than the first disk part 61. The outer surface of the first disk part 61 has an uneven structure so that the subject or the like does not slip when rotating the rotating part 60. The female thread part 61x is a cylindrical member with a female thread cut on the inner surface. The first disk part 61 has a through hole 61y.

[0056] The second disk portion 62 has a through hole 62x in the center. The second disk portion 62 also has a ring-shaped protrusion 62y that is provided so as to surround the through hole 62x in a plan view, and the outside of the protrusion 62y is a ring-shaped step surface 62a. The step surface 62a is, for example, perpendicular to the axial direction of the second disk portion 62. The second disk portion 62 has a through hole 62z.

[0057] The connecting part 50 is, for example, a cylindrical member with both ends open. The connecting part 50 has a ring-shaped flange part 50f protruding radially inward from the outer surface at the end on the first disk part 61 side. The connecting part 50 has a through hole 50x on the side surface. For example, two through holes 50x can be arranged to face each other across the center of the connecting part 50 in a plan view.

[0058] The second disk portion 62 is housed in the connecting portion 50 and is fixed to the first disk portion 61 with the flange portion 50f sandwiched between them. Specifically, the first disk portion 61 and the second disk portion 62 are screwed together with the screw 63 with the flange portion 50f of the connecting portion 50 sandwiched between the lower surface of the first disk portion 61 and the step surface 62a of the second disk portion 62. With this structure, the connecting portion 50 does not come off the rotating portion 60 composed of the first disk portion 61 and the second disk portion 62. The rotating portion 60 is freely rotatable with respect to the connecting portion 50.

[0059] The structure including the connecting portion 50 and the rotating portion 60 is placed on the fixed portion 40. At this time, the female threaded portion 61x of the first disk portion 61 and the male threaded portion 33 of the movable portion 30 are screwed together so as to be freely rotatable. This connects the cover portion 32 to the rotating portion 60. Then, the through hole 41x of the fixed portion 40 and the through hole 50x of the connecting portion 50 are aligned and screwed together by the screw 64, and the connecting portion 50 is fixed to the cylindrical portion 41. This allows the rotating portion 60 to be freely rotatable with respect to the fixed portion 40.

[0060] Fig. 11 is a cross-sectional view illustrating the sensor unit. As shown in Fig. 11, the movable unit 30 does not rotate relative to the fixed unit 40, but reciprocates in the axial direction of the cylindrical unit 41 with the rotation of the rotating unit 60. That is, when the rotating unit 60 including the first disk unit 61 and the second disk unit 62 rotates in the direction of arrow A, the screwing state between the female thread unit 61x and the male thread unit 33 changes, and the movable unit 30 including the pulse wave sensor 20 reciprocates in the axial direction of the cylindrical unit 41 (direction of arrow B). The movable unit 30 can be configured to be movable from a position where the strain body 22 protrudes from the lower end of the fixed unit 40 to a position above the lower end of the fixed unit 40.

[0061] With this structure, when the pulse wave measuring device 1 is not worn on the subject, the position of the movable part 30 can be adjusted so that the strain body 22 is located above the lower end of the fixed part 40. As a result, when the pulse wave measuring device 1 is worn on the subject, the strain body 22 does not come into contact with the subject, so plastic deformation of the strain body 22 can be suppressed.

[0062] Moreover, after the pulse wave measuring device 1 is attached to the subject, the rotating part 60 is rotated to change the position of the movable part 30, thereby allowing the subject's radial artery to be appropriately pressed. At this time, for example, the rotating part 60 may be rotated while monitoring the pulse wave signal obtained from the pulse wave sensor 20, and the amplitude of the pulse wave signal may be adjusted to be as large as possible. Alternatively, an audio signal or optical signal may be generated to notify the subject that the amplitude of the pulse wave signal has entered a predetermined range, thereby informing the subject of the optimal adjustment position of the movable part 30.

[0063] FIG. 12 is a cross-sectional view (part 1) for explaining the pivot portion. As shown in FIG. 12, the lid portion 32 has a first surface 32a and a second surface 32b opposite to the first surface 32a. The first surface 32a and the second surface 32b are, for example, parallel to each other. A recess 32y that opens to the first surface 32a is provided at the approximate center of the first surface 32a of the lid portion 32. The inner surface of the recess 32y is, for example, a curved surface that is inclined with respect to the axial direction of the male thread portion 33. In a cross-sectional view, the inner surface of the recess 32y may be partially or entirely curved.

[0064] The recess 32y is, for example, conical or truncated conical. The recess 32y may be cylindrical with a diameter larger than that of the pivot portion 23p. From the viewpoint of reducing the backlash between the pivot portion 23p and the recess 32y and facilitating centering, it is preferable that the inner surface of the recess 32y is a single curved surface that is inclined with respect to the axial direction of the sensor unit 10, such as a conical or truncated conical shape.

[0065] The recess 32y is disposed at a position overlapping with the male thread portion 33 when viewed in the axial direction of the movable portion 30 (the vertical direction in FIG. 12), and a part of the recess 32y may be disposed within the male thread portion 33. In this way, the cover portion 32 can be partially thinned.

[0066] The first surface 23a of the facing portion 23 and the first surface 32a of the lid portion 32 face each other. In the facing portion 23, the tip side (the recess 32y side) of the pivot portion 23p is, for example, dome-shaped. Here, the dome shape refers to a shape in which the height is greatest near the central axis with respect to the first surface 23a, and the height decreases toward the periphery. The tip side of the pivot portion 23p may be part of a spherical surface or part of an aspherical surface.

[0067] Flange portion 23f of facing portion 23 is disposed between step surface 31a of sensor holding portion 31 and first surface 32a of cover portion 32. With this structure, flange portion 23f serves as a stopper that prevents pulse wave sensor 20 from falling downward from sensor holding portion 31.

[0068] FIG. 13 is a cross-sectional view (part 2) for explaining the pivot portion. In both of FIG. 13, the attachment portion 80 of the pulse wave measuring device 1 is attached to a subject. 300 is a schematic diagram of the radial artery of the subject. When the attachment portion 80 is attached to the subject, as shown in FIG. 13, the strain body 22 of the pulse wave sensor 20 contacts the skin 310 on the radial artery 300 of the subject, the pulse wave sensor 20 is pushed up toward the cover portion 32, and the pivot portion 23p and the recessed portion 32y come into contact with each other. The pivot portion 23p and the recessed portion 32y are in line contact, for example. This can reduce the backlash between the pivot portion 23p and the recessed portion 32y, making centering easier. However, this is not limited to this, and the pivot portion 23p and the recessed portion 32y may be in point contact or surface contact.

[0069] In this way, when the mounting part 80 is not attached to the subject, the pulse wave measuring device 1 is in a first state in which the pivot part 23p and the recess 32y are not in contact with each other (see FIG. 12). Then, when the mounting part 80 is attached to the subject, the state switches to a second state in which the pivot part 23p and the recess 32y are in contact with each other (see FIG. 13).

[0070] 13, when pivot portion 23p comes into contact with recess 32y, pulse wave sensor 20 can swing in any direction of 360 degrees with the contact point between pivot portion 23p and recess 32y as a fulcrum. In other words, the detection surface of strain body 22 of pulse wave sensor 20 can be tilted at any angle along radial artery 300 of the subject.

[0071] This allows the angle of the detection surface of flexure body 22 of pulse wave sensor 20 to follow the radial artery 300 of the subject, so that the detection surface of flexure body 22 can be brought into contact with the radial artery 300 of the subject at an appropriate angle. In other words, the detection surface of flexure body 22 of pulse wave sensor 20 can be disposed approximately parallel to the radial artery 300 of the subject. As a result, it becomes possible to detect minute pulse wave signals, improving the accuracy of pulse wave measurement.

[0072] Furthermore, in pulse wave measuring device 1, pulse wave sensor 20 can be easily positioned on the radial artery by operating first operating unit 87 and second operating unit 88 to transition between the open state and the closed state multiple times and finely adjust the position of pulse wave sensor 20. At this time, it is preferable to monitor the output signal of pulse wave sensor 20 and find the position where the amplitude of the output signal is as large as possible.

[0073] Furthermore, in the pulse wave measuring device 1, a wiring board 90 is provided in the free space of the first curved member 81, and components that contribute to the detection of pulse waves are arranged on the wiring board 90, thereby making it possible to realize a compact pulse wave measuring device equipped with the necessary components.

[0074] Furthermore, since pulse wave measuring device 1 is provided with biasing members 84 and 85, it is possible to apply an appropriate amount of pressure to the subject's radial artery.

[0075] [Pulse wave sensor] Here, a pulse wave sensor having a plurality of strain gauges is shown as an example of the pulse wave sensor 20. Regarding the components of the pulse wave sensor 20, duplicated explanations of those parts that have already been explained will be omitted.

[0076] Fig. 14 is a plan view illustrating the pulse wave sensor according to the first embodiment. Fig. 15 is a cross-sectional view illustrating the pulse wave sensor according to the first embodiment, taken along line AA in Fig. 14.

[0077] 14 and 15, pulse wave sensor 20 has housing 21, strain body 22, opposing portion 23, wire 25, and a plurality of strain gauges (strain gauges 1001, 1002, 1003, 1004). Opposing portion 23 and wire 25 are as described above. 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.

[0078] 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 flat. The flexure body 22 has a first main surface 22m and a second main surface 22n located on the opposite side to the first main surface 22m. The first main surface 22m faces the subject.

[0079] The material of the flexure body 22 may be, for example, metal, ceramic, glass, etc. Examples of metals used as the material of the flexure body 22 include SUS (stainless steel), copper, aluminum, etc. The flexure body 22 may be integrally formed, for example, by a press processing method or the like. The thickness t of the flexure body 22 excluding the load portion 22c is constant. The thickness t may be, for example, 0.03 mm or more and 0.3 mm or less.

[0080] In the explanation of Figs. 14 and 15, 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 main surface 22m of the flexure body 22. The planar shape refers to the shape of the object when viewed in the normal direction.

[0081] In the pulse wave sensor 20, the housing 21 is a portion that holds the strain generating body 22. The housing 21 can be made of, for example, metal, resin, or the like.

[0082] In the flexure body 22, the base 22a is a circular frame-shaped (ring-shaped) region outside the circular dashed line shown in FIG. 14. 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.

[0083] 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. 14, 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.

[0084] The load portion 22c is provided on the beam portion 22b. The load portion 22c is provided, for example, in a region where 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 a part of the first main surface 22m of the strain body 22.

[0085] 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.

[0086] The output signal 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 main 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.

[0087] 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.

[0088] The strain gauges 1001 to 1004 are connected to form each side of a bridge circuit, and the output signal of the pulse wave sensor 20 (a signal indicating a pulse wave) can be generated by the bridge circuit. FIG. 16 is an example of a bridge circuit. In the bridge circuit shown in FIG. 16, 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.

[0089] 16, a DC voltage E is supplied between the connection part of the upper left side and the lower left side and the connection part of the upper right side and the lower right side. This allows an analog voltage output signal S1 to be obtained between the connection part of the upper left side and the upper right side and the connection part of the lower left side and the lower right side. The wiring pattern constituting the bridge circuit can be provided on a wiring board 90, for example.

[0090] 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.

[0091] 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.

[0092] [Strain gauge 100] Fig. 17 is a plan view illustrating the strain gauge according to the first embodiment. Fig. 18 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. 17.

[0093] 17 and 18, 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. 17 and 18. First, each part constituting the strain gauge 100 will be described in detail.

[0094] In the explanation of the strain gauge using Figs. 17 to 19, the definition of the upper surface and the lower surface is different from that in the other figures. Specifically, in Figs. 17 to 19, 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 main surface 22n of the flexure body 22 such that the base material 110 faces the second main surface 22n of the flexure body 22.

[0095] 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 main 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.

[0096] 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.

[0097] 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.

[0098] 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.

[0099] 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. 17 as having a high-density matte pattern.

[0100] The resistor 130 has a structure in which multiple elongated portions are arranged at predetermined intervals with their longitudinal direction in the same direction (the direction of line BB in the example of FIG. 17), and the ends of adjacent elongated portions are alternately connected to form a zigzag fold as a whole. The longitudinal direction of the multiple elongated portions is the grid direction, and the direction perpendicular to the grid direction is the grid width direction (the direction perpendicular to line BB in the example of FIG. 17).

[0101] 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.

[0102] 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).

[0103] 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.

[0104] 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.

[0105] 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.

[0106] 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).

[0107] 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.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 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. 17 with a matte pattern that is less dense than the resistor 130.

[0112] The electrode 150 is provided on the substrate 110. The electrode 150 is electrically connected to the resistor 130 via the wiring 140. The electrode 150 is 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 electrode 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. 17, the electrode 150 is shown with a matte pattern having the same density as the wiring 140 for convenience.

[0113] 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.

[0114] [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.

[0115] 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.

[0116] 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. 17.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] 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.

[0121] 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.

[0122] 19 is a cross-sectional view (part 2) illustrating the strain gauge according to the first embodiment. FIG 19 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.

[0123] 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.

[0124] 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.

[0125] First Modification of the First Embodiment In the first modification of the first embodiment, an example in which a biasing member is disposed between the pulse wave sensor and the cover is shown. Note that in the first modification of the first embodiment, the description of the same components as those in the already described embodiments may be omitted.

[0126] Fig. 20 is a first diagram for explaining the urging member, and is a partial cross-sectional view showing the sensor unit 10, the pulse wave sensor 20, and the cover unit 32. Fig. 20 differs from the structure shown in Fig. 12 in that a urging member 400 is disposed inside the sensor unit 10, between the opposing surfaces of the facing portion 23 and the cover unit 32.

[0127] The biasing member 400 can be disposed between the first surface 23a of the facing portion 23 and the first surface 32a of the lid portion 32 so as to be in contact with the first surface 23a of the facing portion 23 and the first surface 32a of the lid portion 32. By disposing the biasing member 400, the pulse wave sensor 20 can be biased in a direction away from the first surface 32a of the lid portion 32.

[0128] Fig. 21 is a diagram (part 2) for explaining the biasing member, and is a perspective view showing only the biasing member. As shown in Fig. 21, the biasing member 400 is, for example, a helical (spiral) leaf spring. The biasing member 400 can be disposed so that the pivot part 23p is approximately at the center in a plan view. The biasing member 400 can be formed of, for example, metal, resin, rubber, etc.

[0129] The biasing member 400 may be a conical spring or a cylindrical spring, but in the case of a conical spring, the height when compressed can be made lower than in the case of a cylindrical spring, making it possible to reduce the height of the sensor unit 10. In the case of a conical spring as the biasing member 400, it is preferable to arrange the portion of the conical spring with a smaller diameter facing the lid unit 32 in order to stably arrange the biasing member 400.

[0130] As long as the biasing member 400 can bias the pulse wave sensor 20 in a direction away from the first surface 32a of the cover portion 32, the shape and material of the biasing member 400 are not important.

[0131] In this manner, by disposing the biasing member 400, even if vibrations or the like are applied to the pulse wave sensor 20 when it is not in contact with the subject's wrist or the like, the flange portion 23f can be maintained in contact with the step surface 31a, thereby preventing rattling from occurring between the pulse wave sensor 20 and the lid portion 32. This can reduce the risk of abnormal noise being generated when the pulse wave measuring device 1 is carried around, for example.

[0132] Second Modification of the First Embodiment In the second modification of the first embodiment, an example is shown in which a cover member is attached to the first main surface side of the strain body of the pulse wave sensor. Note that in the second modification of the first embodiment, the description of the same components as those in the already described embodiments may be omitted.

[0133] 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.

[0134] Fig. 22 is a cross-sectional view (part 1) showing a state in which a cover member is attached to a pulse wave sensor. In Fig. 22, as an example, cover member 500 has a gap 520 between it and strain body 22, and the surface (the side that touches the subject's skin) has a substantially hemispherical shape. Also, a convex portion 510 is provided in the center of cover member 500, and convex portion 510 and load portion 22c are provided so as to face each other.

[0135] The convex portion 510 and the flexure body 22 (loading portion 22c in the case of FIG. 22) may be designed to be in contact with each other when no pressure is applied to the cover member 500, or may be designed to have a gap therebetween as shown in FIG. 22. That is, the convex portion 510 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 510 is designed to be in contact with the flexure body 22 (loading portion 22c in the case of FIG. 22) and transmit pressure when the cover member 500 is pressed against the body of the measurement subject. With such a design, the pressure applied to the cover member 500 can be concentrated on the portion of the flexure body 22 with which the convex portion 510 is in contact. Therefore, stress can be concentrated in a specific area of ​​the flexure body 22.

[0136] Moreover, by covering the flexure body 22 with the cover member 500, 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.

[0137] The shape of the cover member 500 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 main surface 22m of the strain generating body 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 500 even if the way in which the measurement object contacts the cover member 500 (i.e., the magnitude of the pressing force pressing the cover member 500 against the measurement object, which part of the cover member 500 is in contact with the measurement object, and the angle at which the cover member 500 is pressed against the measurement object) changes.

[0138] A preferred example of the above-mentioned "shape that allows pressure to be applied relatively evenly" is a hemispherical cover member 500 as shown in Fig. 22. In this manner, the upper surface of the cover member 500 can be a curved surface that is highest above the center of the first main surface 22m of the flexure body 22, with the first main surface 22m of the flexure body 22 as the reference, and that becomes lower toward the periphery of the first main surface 22m of the flexure body 22.

[0139] Other examples of the shape of the cover member 500 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 500 on the measurement target side may be a surface including such a conic section.

[0140] The cover member 500 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 500 may have a shape such that a vertical line at an arbitrary point on the surface of the cover member 500 on the measurement target side intersects with a vertical line of the first main surface 22m passing through the center of the first main surface 22m of the strain body 22.

[0141] Fig. 23 is a cross-sectional view (part 2) showing a state in which a cover member is attached to a pulse wave sensor. Cover member 530 shown in Fig. 23 differs from cover member 500 shown in Fig. 22 in that there is no clearly protruding portion such as convex portion 510 on the surface facing strain body 22. Other points of cover member 530 may be the same as cover member 500, or may be modified in the same manner as cover member 500.

[0142] At least a part of the surface of the cover member 530 facing the flexure body 22 is curved toward the flexure body 22. In this modification, the entire curved surface of the cover member 530 functions as a convex portion. In the example of FIG. 23, the center of the surface of the cover member 530 facing the flexure body 22 is a curved surface that is gently inclined toward the flexure body 22. With this design, the pressure applied to the cover member 530 can be concentrated at the portion where the cover member 530 and the flexure body 22 contact each other (for example, the load portion 22c of the flexure body 22). Therefore, the cover member 530 allows the pulse wave sensor 20 to concentrate stress in a specific area of ​​the flexure body 22. In addition, as with the cover member 500, even when the cover member 530 is used, it is possible to prevent the intrusion of dirt, dust, and the like through the circular opening of the flexure body 22. In addition, even if the flexure body 22 is made of metal, it is possible to prevent the subject from having a metal allergy.

[0143] Like the cover member 500, the shape of the cover member 530 is not limited to a hemisphere. For example, as described in the description of the cover member 500, the cover member 530 may have a shape having a surface including a rotational conic section, a shape having a spline surface, or a shape having a surface obtained by approximating a surface including a rotational conic section with straight lines and curves.

[0144] Although preferred embodiments have been described above in detail, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the claims.

[0145] For example, in the above embodiment, an example has been shown in which the pivot portion 23p is provided on the first surface 23a of the facing portion 23, and a recess 32y into which the pivot portion 23p can be inserted is opened on the first surface 32a of the lid portion 32. However, the present invention is not limited to this, and a structure may be used in which a pivot portion is provided on the first surface 32a of the lid portion 32, and a recess into which the pivot portion can be inserted is opened on the first surface 23a of the facing portion 23. In other words, any structure may be used as long as a pivot portion is provided on one of the opposing surfaces of the facing portion 23 and the lid portion 32, and a recess into which the pivot portion can be inserted is opened on the other surface.

[0146] The relationship between the female screw portion 61x of the first disk portion 61 and the male screw portion 33 of the movable portion 30 may be reversed. That is, the first disk portion 61 may be provided with a male screw portion, the movable portion 30 may be provided with a female screw portion, and the two may be screwed together. When the male screw portion 33 is provided on the movable portion 30 side, it is preferable that the male screw portion 33 is configured with a left-handed screw. As a result, when the rotating portion 60 is rotated clockwise, the movable portion 30 moves downward, and when the rotating portion 60 is rotated counterclockwise, the movable portion 30 moves upward, which makes it easy for the user of the pulse wave measuring device 1 to understand and operate. On the other hand, when the male screw portion is provided on the first disk portion 61 side, it is preferable that the male screw portion is configured with a right-handed screw. As a result, the same operation as above is performed, which makes it easy for the user of the pulse wave measuring device 1 to understand and operate.

[0147] Furthermore, the structure of the pulse wave sensor 20 is not limited to that shown in Fig. 14 etc., and may be any structure. For example, a structure in which no slits are provided around the beam portion may be used. [Explanation of symbols]

[0148] 1 Pulse wave measuring device, 10 Sensor part, 20 Pulse wave sensor, 21 Housing, 21x Groove, 22 Strain generating body, 22m First main surface, 22n Second main surface, 23 Opposing part, 23a First surface, 23f Flange part, 23p Pivot part, 23x Through hole, 23y Notch part, 30 Movable part, 31 Sensor holding part, 31a Step surface, 31b Positioning part, 31x, 31y Groove, 32 Lid part, 32x Through hole, 33 Male thread part, 40 Fixed part, 41 Cylindrical part, 41a Step surface, 41b Inner surface, 41c Convex part, 41x Through hole, 41y Notch part, 42 Flange part, 42x Through hole, 50 Connecting part, 50f Flange part, 50x Through hole, 60 Rotating portion, 61 first disk portion, 61x female thread portion, 61y through hole, 62 second disk portion, 62a step surface, 62x through hole, 62y protrusion portion, 80 mounting portion, 81 first curved member, 82 second curved member, 82z notch portion, 83 cover portion, 84, 85 biasing member, 86 swing shaft, 87 first operating portion, 88 second operating portion, 90 wiring board, 1001, 1002, 1003, 1004 strain gauge, 300 radial artery, 310 skin, 400 biasing member, 500, 530 cover member, 510 convex portion, 520 gap

Claims

1. It has a sensor section including a pulse wave sensor, and an attachment section connected to the outside of the sensor section and attachable to a subject, The attachment portion has a first curved member and a second curved member that are curved in opposite directions and face each other so that they can be attached to the subject's wrist, and are capable of transitioning between a closed state and an open state. The sensor unit is positioned on one end of the first curved member in the longitudinal direction. The second curved member has a region in which the width in the short direction is narrower than the width of the first curved member in the short direction. A pulse wave measuring device wherein the second curved member divides the maximum width portion in the short direction into two and has an asymmetric shape with respect to a virtual line extending in the longitudinal direction.

2. The second curved member is provided with a notch extending from one end in the shorter direction of the second curved member toward the side of the imaginary line. The pulse wave measuring device according to claim 1, wherein the region is adjacent to the notch in the short direction of the second curved member.

3. The pulse wave measuring device according to claim 2, wherein the notch is located on the side of the second curved member that is closer to the sensor in the longitudinal direction.

4. The pulse wave measuring device according to claim 3, wherein, in a view from below, the center of the sensor portion is located closer to the notch portion than the imaginary line in the short direction of the second curved member.

5. The pulse wave measuring device according to any one of claims 1 to 4, wherein the width in the short direction of the second curved member on the side further from the sensor portion than the region in the longitudinal direction is the same as the width in the short direction of the first curved member.

6. The sensor unit comprises a fixed part including a cylindrical part, a movable part housed inside the cylindrical part, and a rotating part that closes one opening of the cylindrical part and rotates relative to the fixed part with the central axis of the cylindrical part as the axis of rotation. The aforementioned movable part is Sensor holding part, The pulse wave sensor and, It has a cover portion fixed to the other axial end of the sensor holding portion and connected to the rotating portion, The pulse wave sensor comprises a housing, a strain generating body provided on one side of the housing, and a counter portion provided on the other side of the housing, wherein the strain generating body is held inside the sensor holding portion such that it is exposed from one end of the sensor holding portion in the axial direction. A pivot portion is provided on one of the opposing surfaces of the opposing portion and the lid portion, and a recess into which the pivot portion can be inserted is provided on the other surface. When the pivot portion and the recess come into contact, the pulse wave sensor becomes capable of swinging with the contact point between the pivot portion and the recess as the pivot point. The strain-generating body is exposed from the other opening of the cylindrical portion, The pulse wave measuring device according to any one of claims 1 to 4, wherein the movable part does not rotate relative to the fixed part, but reciprocates in the axial direction of the cylindrical part in conjunction with the rotation of the rotating part.

7. The movable part has a first threaded portion that protrudes from the lid in the direction opposite to the strain-generating body, The rotating portion has a first disc portion which has a second threaded portion that protrudes toward the strain generating body, One of the first threaded portion and the second threaded portion is a male threaded portion, and the other is a female threaded portion. The male threaded portion and the female threaded portion are rotatably screwed together. The pulse wave measuring device according to claim 6, wherein when the first disc portion rotates, the screwed state between the male screw portion and the female screw portion changes, and the movable portion reciprocates in the axial direction of the cylindrical portion.

8. The rotating part further has a second disc portion which has a smaller diameter than the first disc portion. The aforementioned fixing portion has a cylindrical connecting portion with both ends open, The connecting portion has a first flange portion at the end of the first disc portion that protrudes radially inward from the outer surface, The second disc portion is housed in the connecting portion and fixed to the first disc portion with the first flange portion sandwiched between them. The pulse wave measuring device according to claim 7, wherein the connecting portion is fixed to the cylindrical portion.

9. The opposing portion has a second flange portion that protrudes radially outward from the outer surface of the housing, The sensor holding portion has a stepped surface that protrudes toward the central axis, The second flange portion is positioned between the stepped surface and the cover portion. The pulse wave measuring device according to claim 6, wherein the second flange portion serves as a stopper to prevent the pulse wave sensor from falling out of the sensor holding portion.

10. The sensor holding portion is provided above the stepped surface and has a positioning portion that protrudes from the inner surface toward the central axis, The opposing portion has a notch that is recessed from the outer circumference towards the center, The pulse wave measuring device according to claim 9, wherein the pulse wave sensor is held inside the sensor holding portion with the notch aligned with the positioning portion and is prevented from rotating relative to the sensor holding portion.

11. The sensor holding portion has a groove that is recessed from the outer surface toward the center, The groove is elongated with the axial direction of the sensor holding portion as its longitudinal direction. The cylindrical portion has a protrusion that extends from the inner surface toward the central axis, The pulse wave measuring device according to claim 6, wherein the protrusion and the groove are fitted together, the sensor holding portion is prevented from rotating relative to the cylindrical portion, and its range of movement is restricted to the length of the longitudinal direction of the groove.

12. The pulse wave measuring device according to claim 6, wherein a biasing member is disposed between the opposing surfaces of the opposing portion and the lid portion, biasing the pulse wave sensor in a direction away from the lid portion.

13. The strain generating body has a plurality of strain gauges, The pulse wave measuring device according to claim 6, wherein the pulse wave sensor detects a pulse wave based on the change in the resistance value of the resistors of a plurality of strain gauges.

14. The plurality of strain gauges include a pair of strain gauges for detecting the compressive strain of the strain-generating body and another pair of strain gauges for detecting the tensile strain of the strain-generating body, The pair of strain gauges and the other pair of strain gauges are connected to form each side of a bridge circuit. The pulse wave measuring device according to claim 13, wherein the signal indicating the pulse wave is generated by the bridge circuit.

15. The strain generating body comprises a first main surface and a second main surface located on the opposite side of the first main surface. Multiple strain gauges are arranged on the second main surface. The pulse wave measuring device according to claim 13, wherein a cover member is attached to the first main surface side.

16. The first curved member has a wiring board positioned between one end and the other end in the longitudinal direction. The pulse wave measuring device according to any one of claims 1 to 4, wherein components contributing to pulse wave detection are arranged on the wiring board.

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