JP2016129635A - Sensor module and sensing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sensor module that can suppress an influence from a disturbance, and to provide a sensing device.SOLUTION: In the sensor module 100A, a rigid body 20 is provided to a first implement substrate 11B of a first sensor 11, whereby the first sensor 11 can detect a signal from a detection object M abutting on the rigid body 20 with high accuracy. A second sensor 12 is connected to the first sensor 11 via a buffer member 30A, whereby the second sensor 12 can efficiently detect a disturbance signal. Thus, the influence from the disturbance can be suppressed by obtaining a difference between them.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a sensor module using a piezoelectric element, and a sensing device including the sensor module.

  Patent Document 1 discloses a broadband sensor that can efficiently detect sound waves, pulse waves, and the like. This broadband sensor includes an insulating substrate, a piezoelectric element mounted on the surface of the insulating substrate, a cylindrical member attached to the surface of the insulating substrate so as to surround the piezoelectric element, and having an opening at least at a portion facing the piezoelectric element, and a piezoelectric member Output means for taking out the output of the element (see, for example, the abstract of Patent Document 1).

International Publication No.2013 / 145352

  Since the broadband sensor shown in FIG. 1 of Patent Document 1 uses a piezoelectric element, it can detect a signal to be detected with high sensitivity and broadband, but it can easily detect a signal due to disturbance in addition to the signal to be detected. There are drawbacks.

  The objective of this invention is providing the sensor module and sensing apparatus which can suppress the influence of a disturbance.

In order to achieve the above object, a sensor module according to the present invention includes a first sensor, a rigid body, a buffer member, and a second sensor.
The first sensor includes a first piezoelectric element and a first mounting substrate on which the first piezoelectric element is mounted.
The rigid body is provided on the first mounting board.
The second sensor includes a second piezoelectric element and a second mounting substrate on which the second piezoelectric element is mounted, and is provided in the first sensor via at least the buffer member.
By providing the rigid body on the first mounting substrate of the first sensor, the first sensor can detect the signal from the detection target in contact with the rigid body with high sensitivity. In addition, since the second sensor is provided in the first sensor via the buffer member, the second sensor detects a signal of a type different from the type of signal detected by the first sensor, that is, a signal due to disturbance. Can do. Thereby, the influence of disturbance can be suppressed.

  The rigid body may be provided so as to surround the first piezoelectric element.

The sensor module may further include a sealing member that seals the first piezoelectric element in the rigid body.
Accordingly, at least a part of the first piezoelectric element and the first mounting substrate is not exposed to the outside, so that the durability of the first sensor is improved.

The sealing member may be made of the same material as that of the buffer member.
Thereby, manufacture of this sensor module becomes easy and cost reduction is realizable.

The sealing member may be configured integrally with the buffer member and seal the second sensor within the rigid body.
Thereby, since not only the 1st sensor but the 2nd sensor is not exposed outside, the endurance of the 2nd sensor improves.

The end surface of the sealing member opposite to the side on which the first mounting substrate is disposed may protrude from the end surface of the rigid body opposite to the side on which the first mounting substrate is disposed. .
Thereby, when a sensor module is mounted on the user's body, the user's wearing feeling is improved.

The sensor module may further include a sealing member configured to seal the second piezoelectric element, which is configured separately from the sealing member.
Thereby, since at least a part of the circuit of the second piezoelectric element and the second mounting substrate is not exposed to the outside, the durability of the second sensor is improved.

The rigid body may have a signal introduction end face for introducing a signal from a detection target, and the first sensor and the second sensor may be arranged along an axis perpendicular to the signal introduction end face.
Thereby, the first sensor can efficiently obtain a signal (including a signal) substantially the same as the signal to be acquired by the second sensor. For example, when the disturbance correction calculation (calculation for removing the influence of disturbance) is performed using the output values of the first sensor and the second sensor, the disturbance correction calculation can be performed easily and with high accuracy.

  The first piezoelectric element and the second piezoelectric element may be disposed coaxially with the vertical axis.

A sealing member that has a lower hardness than the rigid body and seals the second piezoelectric element; and the second sensor is disposed at a position where the sealing member can contact a detection target. In addition, the first sensor may be provided via the buffer member.
Thereby, the sensor module can be thinned.

  You may further comprise the connection board | substrate with which the said 1st mounting board | substrate was mounted. The second sensor may be provided on the connection board via the buffer member. The connection board may be a circuit board having a circuit.

  The first mounting board may have a surface on which the first piezoelectric element is mounted, and the second mounting board may be disposed on the surface of the first mounting board via the buffer member.

  The buffer member may have a Shore hardness of 1 or more and 100 or less.

You may have the differential amplifier mounted in the said 1st mounting board | substrate or the said 2nd mounting board | substrate, and being electrically connected to the output side of the said 1st piezoelectric element and the said 2nd piezoelectric element.
Thereby, the sensor module can output the differentially amplified analog signal to an external device.

The sensor module may further include an AD converter and an arithmetic unit. The AD converter is mounted on the first mounting board or the second mounting board, and is electrically connected to the output side of the first sensor and the second sensor.
The computing unit is mounted on the first mounting board or the second mounting board, and is electrically connected to the output side of the AD converter.
Thereby, the sensor module can output the digital signal calculated by the calculator to an external device.

A sensing device according to the present invention includes the above-described sensor module and processing means.
The processing means is configured to process signals output from the first sensor and the second sensor.

  The processing means includes an AD converter electrically connected to the output side of the first sensor and the second sensor, and an arithmetic unit electrically connected to the output side of the AD converter. May be.

  The processing means may include a transmitter that transmits a signal output from the sensor module by wireless communication, and a receiver that receives a signal transmitted from the transmitter.

  As described above, according to the present invention, the influence of disturbance can be suppressed.

FIG. 1A is a cross-sectional view schematically showing a sensor module according to the first embodiment of the present invention. FIG. 1B is a cross-sectional view schematically showing a sensor module in which the signal introduction end surface of the rigid body and the end surface of the sealing member have the same height. FIG. 2 is a block diagram illustrating an example of an electrical configuration of the sensor module. FIG. 3A is a graph showing a detection signal by the first sensor. FIG. 3B is a graph showing a detection signal by the second sensor. FIG. 3C is a graph showing an output signal of the sensor module. FIG. 4 is a cross-sectional view schematically showing a sensor module according to the second embodiment of the present invention. FIG. 5 is a cross-sectional view schematically showing a sensor module according to the third embodiment of the present invention. FIG. 6 is a cross-sectional view schematically showing a sensor module according to the fourth embodiment of the present invention. FIG. 7 is a cross-sectional view schematically showing a sensor module according to the fifth embodiment of the present invention. FIG. 8 is a cross-sectional view schematically showing a sensor module according to the sixth embodiment of the present invention. FIG. 9 is a cross-sectional view schematically showing a sensor module according to the seventh embodiment of the present invention. FIG. 10 is a table showing the relationship between Shore hardness and defined α. FIG. 11 is a block diagram illustrating another example of the electrical configuration of the sensor module. FIG. 12 is a block diagram showing an electrical configuration of a sensing device including a sensor module. FIG. 13 is a block diagram illustrating an electrical configuration of a sensing device according to yet another example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  The sensor module according to the embodiment of the present invention can be used mainly in a measuring apparatus that measures a pulse, an arrhythmia, a blood vessel hardness, and the like by detecting minute vibrations generated in a living body.

  The sensor module according to each embodiment described below includes two sensors. The sensor module is configured such that one of the sensors detects a signal of the detection target M, and the other detects a signal generated due to a disturbance.

  [First Embodiment]

(Configuration of sensor module)
FIG. 1A is a cross-sectional view schematically showing a sensor module according to the first embodiment of the present invention. The sensor module 100A includes a first sensor 11, a second sensor 12, a rigid body 20, a buffer member 30A, and a sealing member 30B.

  The first sensor 11 includes a first piezoelectric element 11P and a first mounting substrate 11B on which the first piezoelectric element 11P is mounted. The second sensor 12 includes a second piezoelectric element 12P and a second mounting substrate 12B on which the second piezoelectric element 12P is mounted. Substantially similar elements are used as the first piezoelectric element 11P and the second piezoelectric element 12P.

  The first mounting substrate 11B and the second mounting substrate 12B are resin substrates including an electric circuit. The first mounting substrate 11B and the second mounting substrate 12B are typically rectangular, but may be circular, elliptical, or other shapes. For example, the first mounting substrate 11B and the second mounting substrate 12B may be mounting substrates employing a “component built-in substrate” technology in which a recess is provided in a resin substrate and an electronic component is disposed in the recess. Thereby, size reduction and thickness reduction of the 1st sensor 11 and the 2nd sensor 12 are realizable.

  The first mounting board 11B and the second mounting board 12B are electrically connected by, for example, an electric cable 15. The electric cable 15 passes through the buffer member 30A. In order to suppress mutual vibration transmission between the first mounting board 11B and the second mounting board 12B, it is preferable that the electric cable 15 is a thin thin wire with a small rigidity.

  The rigid body 20 is connected and fixed to the first mounting substrate 11B, for example, and is provided on the first mounting substrate 11B so as to surround the first piezoelectric element 11P. Typically, the rigid body 20 has an annular shape. Specifically, the rigid body 20 has a circular shape when viewed from the axial direction along the direction in which the first sensor 11 and the second sensor 12 are arranged (the vertical direction in FIG. 1A). “Annular” is not limited to an annular shape, and includes a meaning of a polygonal shape of a triangle or more and other random shapes.

  The material of the rigid body 20 is typically a metal, but may be a resin or a ceramic. In the case of a metal, stainless steel, aluminum, iron, copper, etc. are mentioned. As the resin, a relatively high-rigidity resin such as FRP (Fiber Reinforced Plastics) is used. The material of the rigid body 20 is desirably a material that can ensure durability that can withstand actual use and durability such as rust prevention.

  The rigid body 20 has a signal introduction end face 20a at its end. When the sensor module 100A is used, the signal introduction end face 20a abuts on the detection target M that is a part of the living body (user's body) indicated by a dashed line. The rigid body 20 has a function of introducing a movement signal of the detection target M from the signal introduction end face 20a and transmitting the signal to the first piezoelectric element 11P via the first mounting substrate 11B.

  Note that the sensor module 100A includes a housing (not shown) that houses the first sensor 11, the second sensor 12, the rigid body 20, and the cushioning member 30A. This housing has an opening for exposing the signal introduction end face 20a of the rigid body 20 to the outside. A hook-and-loop fastener, a band, an adhesive pad, and the like (not shown) are connected to the casing, and the sensor module 100A is attached to the body by these.

  The first sensor 11 and the second sensor 12 have the same form, and are arranged so that the directions of signal detection by the first piezoelectric element 11P and the second piezoelectric element 12P are substantially the same. Specifically, the first sensor 11 and the second sensor 12 are arranged along an axis perpendicular to the signal introduction end surface 20a of the rigid body 20 (vertical direction in FIG. 1A). Further, in the present embodiment, the first piezoelectric element 11P and the second piezoelectric element 12P are arranged coaxially on the axis.

  A buffer member 30 </ b> A is interposed between the first sensor 11 and the second sensor 12. That is, the second sensor 12 is connected to the first mounting substrate 11B of the first sensor 11 via the buffer member 30A. The buffer member 30A functions as a sealing member (separate from the sealing member 30B) provided to seal the second piezoelectric element 12P, and covers the mounting surface of the second mounting substrate 12B. Is provided. Thereby, since the mounting surfaces of the second piezoelectric element 12P and the second mounting substrate 12B are not exposed to the outside, effects such as dust resistance and waterproofing are promoted, and the durability of the second sensor 12 is improved.

  The sealing member 30B is provided on the first mounting substrate 11B so as to seal the first piezoelectric element 11P in the rigid body 20. By providing the sealing member 30B, and by covering the opposite surface of the mounting surface of the first mounting substrate 11B with the buffer member 30A, the first piezoelectric element 11P and the first mounting substrate 11B are exposed to the outside. In other words, effects such as dust resistance and waterproofing are promoted, and the durability of the first sensor 11 is improved.

  The material of the sealing member 30B is the same as the material of the buffer member 30A. By using the same material for both, the sensor module can be easily manufactured and the cost can be reduced. As the material of the sealing member 30B and the buffer member 30A, a material having a hardness lower than that of the material of the rigid body 20 or the material of the first mounting substrate 11B and the second mounting substrate 12B is used.

  As the material of the buffer member 30A and the sealing member 30B, a material having a Shore Durometer of 1 or more and 100 or less is used. Desirable Shore hardness is 15 or more and 80 or less, and more desirably 30 or more and 60 or less.

  As a material of the buffer member 30A and the sealing member 30B that realize the Shore hardness, for example, a relatively soft resin such as rubber or grease, or a sponge is used. For example, silicone is used as the rubber material. In addition to silicone, ethylene propylene, urethane, nitrile and the like can be used.

  The material of the sealing member 30B and the material of the buffer member 30A may be different. Even in this case, the sealing member 30B is made of a material having a hardness lower than that of the rigid body 20.

  In the sensor module 100A shown in FIG. 1A, the end surface 31B (the end surface opposite to the side on which the first mounting substrate 11B is disposed) 31B of the sealing member 30B protrudes outward from the signal introduction end surface 20a of the rigid body 20. . The protruding length is 1 mm or less. Thus, the sealing member 30B made of a relatively soft material comes into contact with the user's body, which is the detection target M, together with the rigid body 20, so that the user's pain and discomfort are compared to the case where only the rigid body 20 comes into contact with the body. And the feeling of wearing of the sensor module 100A can be enhanced.

  Of course, the sensor module 100A may be configured such that only the rigid body 20 contacts the detection target M. In this case, the sealing member 30B and the rigid body 20 are arranged such that the end face 31B of the sealing member 30B is lower than the signal introduction end face 20a of the rigid body 20 (so as to be positioned on the first mounting substrate 11B side from the signal introduction end face 20a). Is configured.

  Alternatively, as in the sensor module 100A ′ shown in FIG. 1B, the end surface 31B of the sealing member 30B and the signal introduction end surface 20a of the rigid body 20 may be flush with each other (located in the same plane). Alternatively, the sealing member 30B may be omitted.

(Electrical configuration of sensor module)
FIG. 2 is a block diagram illustrating an example of an electrical configuration of the sensor module 100A for obtaining the detection target signal. A differential amplifier 16 is mounted on the first mounting board 11B. The respective signals output from the first piezoelectric element 11P and the second piezoelectric element 12P are input to the differential amplifier 16. A differential signal of each signal from the first piezoelectric element 11P and the second piezoelectric element 12P output from the differential amplifier 16 is output to an external device (not shown) as an output signal of the sensor module 100A. An external device is, for example, a device configured to present a sensing state or result to a user.

  The differential amplifier 16 may be mounted on the second mounting board 12B instead of being mounted on the first mounting board 11B.

(Operation or usage of sensor module)
The piezoelectric element is an element configured to output acceleration as a signal as is well known. A piezoelectric element generates an electric charge when it receives an inertial force. This charge generation amount is proportional to the inertial force (that is, acceleration). Therefore, the piezoelectric element can output an acceleration signal by converting the charge generation amount into a voltage level.

  When the sensor module 100A is used, the rigid body 20 directly contacts the detection target M as described above. Therefore, the first sensor 11 to which the rigid body 20 is fixed detects an acceleration signal corresponding to the movement of the detection target M. The signals detected by the first sensor 11 include biological signals that are not intended by the user, such as a pulse (a detection target signal that is a signal that should be detected originally), and other disturbance signals (noise).

  The disturbance signal includes, for example, a signal generated when the user intentionally moves the detection target M that is a part of the body, a signal due to unconscious movement having a level higher than a biological signal such as a pulse, and the like. Alternatively, the disturbance signal includes a signal generated by an externally input sound wave or wind pressure.

  On the other hand, the second sensor 12 is not in direct contact with the detection target M and is connected to the first sensor 11 via the buffer member 30A (provided on the first sensor 11 via the buffer member 30A). ). The buffer member 30A is set to a hardness (the above-mentioned predetermined Shore hardness) that absorbs the biological signal (detection target signal). Therefore, the second sensor 12 can effectively detect only the disturbance signal.

  Therefore, the detection target signal can be effectively obtained by taking the difference between the detection signal from the first sensor 11 and the detection signal from the second sensor 12. The differential amplifier 16 outputs this differential signal.

(Measurement result by sensor module)
One of the inventors mounted the sensor module 100A according to the present embodiment on a finger and measured the pulsation (pulse) generated on the finger while intentionally moving the finger randomly. As a measurement result by such an experiment, FIG. 3A is a graph showing a detection signal by the first sensor 11, and FIG. 3B is a graph showing a detection signal by the second sensor 12. FIG. 3C is a graph showing an output signal of the differential amplifier 16, that is, an output signal of the sensor module 100A. In each graph, the unit of the vertical axis is mV. The horizontal axis is time (× 40s). In the graph shown in FIG. 3B, origin correction is performed.

  In the experiment, a period of moving the finger randomly was provided three times in total, and disturbance was intentionally given to the sensor module 100A. As shown in FIG. 3A, it can be seen that a random disturbance signal is generated. On the other hand, as shown in FIG. 3B, the second sensor 12 substantially detects only a disturbance signal. As shown in FIG. 3C, a signal from which disturbance was removed, that is, a detection target signal was obtained.

(Summary)
As described above, according to the sensor module 100 </ b> A according to the present embodiment, the rigid body 20 is provided on the first mounting substrate 11 </ b> B of the first sensor 11, so that the first sensor 11 is in contact with the rigid body 20. The signal from M can be detected with high sensitivity. Further, since the second sensor 12 is provided in the first sensor 11 via the buffer member 30A, the second sensor 12 can efficiently detect a disturbance signal. Therefore, the influence of disturbance can be suppressed by taking these differences.

  In the present embodiment, as described above, the first sensor 11 and the second sensor 12 are arranged along an axis extending in the direction perpendicular to the signal introduction end surface 20a of the rigid body 20. In particular, the first piezoelectric element 11P and the second piezoelectric element 12P are arranged coaxially on the axis. Thereby, the 1st sensor 11 can obtain the signal (including a signal) substantially the same as the signal which the 2nd sensor 12 should acquire efficiently. That is, the same signal as the disturbance signal to be acquired by the second piezoelectric element 12P can be efficiently detected by the first piezoelectric element 11P, and disturbance correction calculation can be performed easily and with high accuracy.

  [Second Embodiment]

  Next, a sensor module according to a second embodiment of the present invention will be described. In the following description, elements that are substantially the same as members and functions included in the sensor module according to the embodiment shown in FIGS. The difference will be mainly described.

  FIG. 4 is a cross-sectional view schematically showing a sensor module according to the second embodiment. In the sensor module 100 </ b> B, the second sensor 12 is sealed by the buffer member 30 in the annular rigid body 20. That is, the buffer member 30 has a function of a sealing member. As described above, when the second sensor 12 is connected to the first sensor 11 via the buffer member 30, the same effects as those of the sensor module 100A according to the first embodiment can be obtained.

  Also in the present embodiment, the first sensor 11 and the second sensor 12 are coaxially disposed along the axis in the vertical direction on the signal introduction end surface 20a of the rigid body 20. This contributes to simplification and high accuracy of disturbance correction calculation.

  [Third Embodiment]

  FIG. 5 is a cross-sectional view schematically showing a sensor module according to the third embodiment of the present invention. In the sensor module 100C, the first sensor 11 and the second sensor 12 are arranged along the axis perpendicular to the signal introduction end surface 20a of the rigid body 20, similarly to the sensor module 100A according to the first embodiment. . However, the first piezoelectric element 11P and the second piezoelectric element 12P are arranged at non-coaxial positions. Thus, the 1st piezoelectric element 11P and the 2nd piezoelectric element 12P do not necessarily need to be arrange | positioned in a coaxial position.

  [Fourth Embodiment]

  FIG. 6 is a cross-sectional view schematically showing a sensor module according to the fourth embodiment of the present invention. As shown in the sensor module 100D, a protective member 30C may be provided on the outer periphery of the rigid body 20. The material of the protection member 30C may be a material used in the buffer member 30A or the sealing member 30B, or may be a different material. By providing the protective member 30C, effects such as rust prevention, waterproofing, and dust prevention are promoted, the rigid body 20 and the first mounting board 11B can be protected, and the durability of the first sensor 11 is improved. In addition, the connectivity between the rigid body 20 and the first mounting substrate 11B can be improved.

  The protective member 30C may be configured to substantially cover both the first mounting board and the second mounting board.

  [Fifth Embodiment]

  FIG. 7 is a cross-sectional view schematically showing a sensor module according to the fifth embodiment of the present invention. In the sensor module 100E, the first sensor 11 and the second sensor 12 are arranged in parallel with respect to the detection target M. Specifically, the second sensor is arranged such that the second piezoelectric element 12P is sealed by the sealing member 30D, and the surface of the sealing member 30D is disposed at a position where the second piezoelectric element 12P can contact the detection target M. 12 is connected to the first sensor 11 via a buffer member 30A. That is, the first sensor 11 and the second sensor 12 are not arranged along the axis in the vertical direction on the signal introduction end surface 20a of the rigid body 20 as in the above embodiments.

  The electrical cable connecting the first sensor 11 and the second sensor 12 is not shown here.

  The buffer member 30A, the sealing member 30D, and the sealing member 30B that seals the first piezoelectric element 11P are preferably made of the same material.

  A rigid body 20 ′ having the same form as the rigid body 20 on the first mounting board 11B is provided on the second mounting board 12B. That is, the first sensor 11 to which the rigid body 20 is attached and the second sensor 12 to which the rigid body 20 ′ is attached are the same product. The rigid body 20 ′ is sealed together with the second piezoelectric element 12P by a sealing member 30D. This prevents the rigid body 20 ′ from coming into contact with the detection target M. Note that the rigid bodies 20 and 20 ′ are not necessarily the same product.

  As described above, in the first sensor 11 and the second sensor 12, by using the same sensor and the rigid bodies 20 and 20 ′, the weight and rigidity can be made the same in both, and equivalent signal detection can be performed. it can. In addition, by using the same components in this way, it is possible to realize easy manufacturing and cost reduction.

  The rigid body 20 ′ may not be attached to the second sensor 12. The same applies to the following embodiments. In this case, it is desirable that the difference in weight and rigidity of the second sensor 12 relative to the first sensor 11 side to which the rigid body 20 is attached be quantitatively canceled by calculation.

  The buffer member 30 </ b> A that connects the first sensor 11 and the second sensor 12 also has a function of fixing and positioning the relative positions of the first sensor 11 and the second sensor 12. The buffer member 30A is not provided only between the first sensor 11 and the second sensor 12, but, for example, is provided so as to cover the entire periphery of the first sensor 11 and the second sensor 12 as illustrated. It may be. Thereby, the said positioning function can be improved and durability of the 1st sensor 11 and the 2nd sensor 12 improves.

  The buffer member 30 </ b> A may be provided only between the first sensor 11 and the second sensor 12.

  As described above, in the present embodiment, the first sensor 11 acquires a motion signal of the detection target M via the rigid body 20, while the second sensor 12 has a lower hardness than the rigid body 20 (20 ′). A motion signal of the detection target M can be acquired via the sealing member 30D. Thereby, since the 1st sensor 11 detects a detection target signal and a disturbance signal, and the 2nd sensor 12 detects a disturbance signal, a detection target signal can be acquired from these differences.

  [Sixth Embodiment]

  FIG. 8 is a cross-sectional view schematically showing a sensor module according to the sixth embodiment of the present invention. In the sensor module 100F according to the present embodiment, the first sensor 11 and the second sensor 12 are arranged in parallel as in the fifth embodiment. The difference is that the sensor module 100G includes a connection board 13 and the first sensor 11 and the second sensor 12 are arranged on the connection board 13. The first mounting board 11B is directly connected to the connection board 13, and the second mounting board 12B is connected to the connection board 13 via the buffer member 30A.

  The connection board 13 is a circuit board whose main material is made of resin. Thereby, the connection substrate 13 can function as a substrate for electrically connecting the first mounting substrate 11B and the second mounting substrate 12B.

  However, the connection board 13 is not a circuit board but may be a metal board or a board made of other materials. In this case, the connection substrate 13 may be in any form as long as it can fix the relative positions of the first sensor 11 and the second sensor 12.

  The buffer member 30A and the sealing member 30D may be integrally provided so as to substantially cover the second mounting substrate 12B. In this case, the buffer member 30A and the sealing member 30D are preferably made of the same material.

  [Seventh Embodiment]

  FIG. 9 is a cross-sectional view schematically showing a sensor module according to the seventh embodiment of the present invention. In the sensor module 100G, the first mounting board 11B of the first sensor 11 has a relatively large size, like the connection board 13 of the sixth embodiment. The second mounting board 12B of the second sensor 12 is connected to the mounting surface of the first mounting board 11B via the buffer member 30A. Even with such a structure, the same effect as the sensor module 100F according to the sixth embodiment can be obtained.

  [Eighth Embodiment]

  As a sensor module according to another embodiment, although not shown, the following sensor module configuration can be realized. For example, it is a configuration in which the first sensor and the second sensor are arranged at intervals such that the detection target is arranged between the first sensor and the second sensor. In this case, the first sensor and the first sensor are arranged (or arranged coaxially) along the axis perpendicular to the signal introduction end face of the rigid body.

  [Shore hardness of cushioning member]

  In this specification, the following α is defined by assuming that the Shore hardness is S and the length (height) of the rigid body 20 in the vertical direction (vertical direction in FIG. 1) with respect to the signal introduction end face 20a of the rigid body 20 is T.

  α = S / T

  FIG. 10 is a table showing the relationship between Shore hardness and α. Here, the material of the buffer member is silicone. In consideration of the practical structure of the sensor module and the arrangement accuracy of each component, α is preferably set to about 5 to 300.

  [Another embodiment of electrical configuration of sensor module, etc.]

(Example 1 of electrical configuration)
FIG. 11 shows another example of the electrical configuration of the sensor module. As the sensor module 101, one of the sensor modules 100A to 100G according to the above embodiments is applied. The sensor module 101 according to this example includes an AD converter 15 connected to the output side of each of the first sensor 11 and the second sensor 12, and an arithmetic unit 17 connected to the output side of the AD converter 15. . The first sensor 11 and the second sensor 12 include an amplifier (not shown) that amplifies the output.

  According to such a configuration, the analog signals output from the first sensor 11 and the second sensor 12 are converted into digital signals by the AD converter 15, and the arithmetic unit 17 performs predetermined arithmetic processing. The computing unit 17 is configured to perform disturbance correction by performing a comparison operation on the digital signal output from each AD converter 15. The calculator 17 may perform a predetermined calculation process such as coefficient calculation or other calculation on at least one of the signals obtained from the AD converters 15 before the comparison calculation.

  The computing unit 17 may be configured to be capable of mounting an application program for presenting (for example, displaying) a sensing state or a result to the user.

(Example 2 of electrical configuration)
FIG. 12 is a block diagram showing an electrical configuration of a sensing device including a sensor module. This sensing device includes a sensor module 102 and processing means 41. As the sensor module 102, one of the sensor modules 100A to 100G according to the above embodiments is applied.

  Similarly to the example shown in FIG. 11, the processing means 41 includes the AD converter 15 and the arithmetic unit 17, and also includes the display unit 18. A device constituting the processing means 41 is a device configured by a computer, for example, a PC (Personal Computer) or a portable terminal such as a smart phone or a tablet. The display 18 may be configured as a separate device from the module including the AD converter 15 and the calculator 17.

(Example 3 of electrical configuration)
FIG. 13 is a block diagram illustrating an electrical configuration of a sensing device according to yet another example. This sensing device includes a sensor module 102 and processing means 42, and the processing means 42 is configured to be connectable to an external device 45. The external device 45 is a computer such as the above-described PC or portable terminal, and is a device that can present a sensing state or a result to the user.

  The processing means 42 includes a transmitter 421 that transmits a signal output from the sensor module by wireless communication, and a receiver 422 that receives a signal transmitted from the transmitter 421. Examples of the wireless communication standard include known standards such as Bluetooth (registered trademark), wireless LAN (Local Area Network), and infrared communication. The receiver 422 and the external device 45 may be configured to communicate with each other by, for example, USB (Universal Serial Bus) or other standards.

  The AD converter (not shown) may be on either the sensor module 102 side or the processing means 42 side.

  [Other various embodiments]

  The present invention is not limited to the embodiment described above, and other various embodiments can be realized.

  The sensor module according to each of the above embodiments includes two piezoelectric elements, but includes three or more piezoelectric elements (three or more sensors) and processes each signal obtained from these three or more sensors. You may make it do. In this case, for example, the first piezoelectric element may detect the signal of the detection target M, and the piezoelectric elements other than the first piezoelectric element may detect disturbances and other noises.

  In each of the above embodiments, the arrangement of the first sensor 11 and the second sensor 12 is set so that the vibration directions detected by the first sensor 11 and the second sensor 12 are substantially the same. The purpose is to enable the first sensor 11 and the second sensor 12 to detect as much vibration as possible as described above. However, the first sensor 11 and the second sensor 12 may be arranged in different directions. In this case, it is desirable to quantitatively cancel the difference in the detection values due to the different detection directions.

  In the sensor module according to the present technology, there may be individual characteristic differences due to variations in element characteristics of the first sensor 11 and the second sensor 12 and variations in the arrangement of these sensors. In order to absorb these variations and individual characteristic differences, the sensor module or sensing device has, for example, a mechanism for detecting the individual characteristic differences, and a calibration function for calibrating an arithmetic expression by an arithmetic unit according to the detection result. You may have.

  In addition to the pulse, the sensor module and the sensing device according to each of the above embodiments can be applied to the following uses. For example, it can be used as a sensor for detecting vibration due to respiration, or as a seating sensor by attaching a plurality of sensor modules to a plurality of positions on the seat.

  The “processing means” of the sensing device is not limited to the above embodiment. For example, the processing means shown in FIG. 12 has the AD converter 15, but the AD converter 15 may be provided on the sensor module 102 side. In this case, the processing means is mainly composed of a device having a computing unit or a device having a computing unit and a display.

  It is also possible to combine at least two feature portions among the feature portions of each embodiment described above. For example, the protection member 30C of the embodiment of FIG. 6 may be applied to the sensor module of the embodiment of FIGS.

DESCRIPTION OF SYMBOLS 11 ... 1st sensor 11B ... 1st mounting board 11P ... 1st piezoelectric element 12 ... 2nd sensor 12B ... 2nd mounting board 12P ... 2nd piezoelectric element 13 ... Connection board 15 ... AD converter 16 ... Differential amplifier 17 ... Arithmetic unit 20, 20 '... Rigid body 20a ... Signal introduction end face 30, 30A ... Buffer member 30B, 30D ... Sealing member 31B ... End face 41, 42 ... Processing means 100A, 100B, 100C, 100D, 100E, 100F, 100G, 101 , 102 ... Sensor module 421 ... Transmitter 422 ... Receiver

Claims (19)

A first sensor having a first piezoelectric element and a first mounting substrate on which the first piezoelectric element is mounted;
A rigid body provided on the first mounting substrate;
A buffer member;
A sensor module comprising: a second piezoelectric element; and a second mounting board on which the second piezoelectric element is mounted, and a second sensor provided at least on the first sensor via the buffer member. The sensor module according to claim 1,
The rigid body is provided so as to surround the first piezoelectric element. The sensor module according to claim 2,
A sensor module further comprising a sealing member for sealing the first piezoelectric element in the rigid body. The sensor module according to claim 3,
The said sealing member is comprised with the same material as the material of the said buffer member. Sensor module. The sensor module according to claim 4,
The said sealing member is comprised integrally with the said buffer member, and seals the said 2nd sensor within the said rigid body Sensor module. The sensor module according to any one of claims 3 to 5,
The end surface of the sealing member opposite to the side on which the first mounting substrate is disposed protrudes outward from the end surface of the rigid body opposite to the side on which the first mounting substrate is disposed. A sensor module. The sensor module according to claim 4,
A sensor module, further comprising a sealing member configured to be separate from the sealing member and sealing the second piezoelectric element. The sensor module according to claim 1,
The rigid body has a signal introduction end face for introducing a signal from a detection target;
The first sensor and the second sensor are arranged along an axis perpendicular to the signal introduction end surface. The sensor module according to claim 8,
The sensor module, wherein the first piezoelectric element and the second piezoelectric element are arranged coaxially with the vertical axis. The sensor module according to claim 1,
A sealing member that has a lower hardness than the rigid body and seals the second piezoelectric element;
The second sensor is provided on the first sensor via the buffer member such that the sealing member is disposed at a position where the sealing member can contact the detection target. The sensor module according to claim 10,
The said sealing member is comprised with the same material as the material of the said buffer member. Sensor module. The sensor module according to claim 10 or 11,
A connection board on which the first mounting board is mounted;
The second sensor is provided on the connection board via the buffer member. The sensor module according to any one of claims 10 and 11,
The first mounting substrate has a surface on which the first piezoelectric element is mounted,
The second mounting substrate is provided on a surface of the first mounting substrate via the buffer member. The sensor module according to any one of claims 1 to 13,
A sensor module, wherein the buffer member has a Shore hardness of 1 or more and 100 or less. The sensor module according to any one of claims 1 to 14,
A sensor module comprising a differential amplifier mounted on the first mounting substrate or the second mounting substrate and electrically connected to the output side of the first piezoelectric element and the second piezoelectric element. The sensor module according to any one of claims 1 to 14,
An AD converter mounted on the first mounting board or the second mounting board and electrically connected to the output side of the first sensor and the second sensor;
A sensor module further comprising: an arithmetic unit mounted on the first mounting substrate or the second mounting substrate and electrically connected to an output side of the AD converter. A first sensor having a first piezoelectric element and a first mounting substrate on which the first piezoelectric element is mounted;
A rigid body provided on the first mounting substrate;
A buffer member;
A second sensor provided on the first sensor via at least the buffer member, the first sensor, and the second sensor; and a second mounting substrate on which the second piezoelectric element is mounted. A sensing device comprising: processing means for processing a signal output from the two sensors. The sensing device according to claim 17,
The processing means includes
An AD converter electrically connected to the output side of the first sensor and the second sensor;
And a computing unit electrically connected to an output side of the AD converter. The sensing device according to claim 17,
The processing means includes
A transmitter for transmitting a signal output from the sensor module by wireless communication;
And a receiver for receiving a signal transmitted from the transmitter.