JP2018077310A - Sensor module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sensor module capable of easily and securely detecting a sound.SOLUTION: A sensor module according to the present invention comprises a film-like piezoelectric sensor and a support for supporting the piezoelectric sensor in a curved state. An average radius of curvature of an outer periphery of a curved part of the piezoelectric sensor is preferably 10 cm or more and 20 cm or less. It is preferable that the support has a low-rigidity part for reducing the transmission of vibration and the piezoelectric sensor is laminated on the low-rigidity part. It is preferable that the piezoelectric sensor has a piezoelectric element and a protective layer laminated on the piezoelectric element and having larger plane area than the piezoelectric element, and the support supports a non-laminated part of the piezoelectric element of the protective layer. Further, it is preferable that the piezoelectric element has a plurality of positioning holes, and the support has a plurality of screws to be coupled to the plurality of positioning holes.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a sensor module.

  Piezoelectric sensors in which a pair of electrodes are laminated on both sides of a porous sheet have been proposed (see JP 2010-89495 A, JP 2010-89496 A, and JP 61-148044 A). This piezoelectric sensor is normally used by electretizing the porous sheet. In this piezoelectric sensor, since the porous sheet has flexibility, the porous sheet is deformed by sound waves or vibrations to generate an electromotive force due to the piezoelectric effect. Therefore, this piezoelectric sensor can detect sound and vibration by being attached to an acoustic device or the like.

JP 2010-89495 A JP 2010-89496 A JP-A-61-148044

  However, the porous sheet is generally formed to a thickness of about several hundred μm or less from the viewpoint of easily and surely performing the polarization treatment, and has low rigidity and is easily bent. For this reason, the piezoelectric sensor is usually used by being adhered to the entire mounting surface so as to be stably held with respect to the mounting surface such as a vibration surface. However, if this piezoelectric sensor is entirely attached to the mounting surface, it is susceptible to the vibration of the mounting surface and it is difficult to detect sound accurately.

  This invention is made | formed in view of such a situation, The objective of this invention is providing the sensor module which can detect a sound easily and reliably.

  The present invention made in order to solve the above-mentioned problems is a sensor module comprising a film-like piezoelectric sensor and a support that supports the piezoelectric sensor in a curved shape.

  The average radius of curvature of the outer periphery of the curved portion of the piezoelectric sensor is preferably 10 cm or more and 20 cm or less.

  The support may include a low-rigidity portion that reduces vibration transmission, and the piezoelectric sensor may be laminated on the low-rigidity portion.

  The piezoelectric sensor may include a piezoelectric element and a protective layer laminated on the piezoelectric element and having a larger planar area than the piezoelectric element, and the support may support a non-laminated portion of the piezoelectric element in the protective layer. .

  The piezoelectric element may have a plurality of positioning holes, and the support may have a plurality of screws connected to the plurality of positioning holes.

  The piezoelectric sensor may have a substantially rectangular shape in plan view, and the support may support both ends of the piezoelectric sensor in the longitudinal direction.

  The sensor module according to the present invention is used, for example, by attaching the surface of the support opposite to the side supporting the piezoelectric sensor to the vibration surface of the musical instrument. In the sensor module, since the piezoelectric sensor is supported in a curved state by the support tool, at least a part of the piezoelectric sensor is held in the air in the curved state. For this reason, the portion of the piezoelectric sensor held in the air is not easily affected by the vibration of the vibration surface, so that sound can be accurately detected. In the sensor module, since the piezoelectric sensor is supported in a curved state by a support, the posture of the piezoelectric sensor is stabilized. As a result, the sensor module can suppress variations in detection signals. Furthermore, the sensor module can be used with being attached to the vibration surface, thereby reducing noise. Therefore, the sensor module can detect sound easily and reliably.

1 is a schematic plan view showing a sensor module according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the sensor module of FIG. 1 taken along line AA. It is a typical perspective view which shows a stringed instrument provided with the sensor module of FIG. FIG. 4 is a schematic plan view showing an inner surface side of a soundboard of the stringed instrument in FIG. 3. It is typical sectional drawing which shows the sensor module which concerns on embodiment different from the sensor module of FIG. FIG. 6 is a schematic plan view showing a sensor module according to an embodiment different from the sensor module of FIGS. 1 and 5. It is a BB sectional view of the sensor module of FIG. FIG. 7 is a schematic plan view showing a sensor module according to an embodiment different from the sensor module of FIGS. 1, 5, and 6. It is CC sectional view taken on the line of the sensor module of FIG. FIG. 9 is a schematic plan view showing a sensor module according to an embodiment different from the sensor module of FIGS. 1, 5, 6, and 8. It is the DD sectional view taken on the line of the sensor module of FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.

[First embodiment]
<Sensor module>
The sensor module 1 of FIG. 1 includes a film-like piezoelectric sensor 2 and a support 3 that supports the piezoelectric sensor 2 in a curved shape. The support 3 holds at least a part of the piezoelectric sensor 2 in the air in a curved state. The support 3 supports the piezoelectric sensor 2 in a both-sided manner.

  As shown in FIG. 2, the piezoelectric sensor 2 includes a sheet-like piezoelectric element 4, a pair of plate-like electrodes 5 a and 5 b laminated on both surfaces of the piezoelectric element 4, and a lead wire that outputs an electric signal to the outside. And a terminal (not shown) to be connected. The piezoelectric sensor 2 has flexibility. The piezoelectric sensor 2 is formed in a substantially rectangular shape in plan view.

  The piezoelectric element 4 is formed in a substantially rectangular shape in plan view. The piezoelectric element 4 is supported by the support 3 on the lower surfaces on both ends facing each other. In the present embodiment, the lower surfaces on both ends in the longitudinal direction are supported on the support 3. The average thickness of the piezoelectric element 4 can be, for example, 30 μm or more and 150 μm or less. The average length in the longitudinal direction of the piezoelectric element 4 can be, for example, 20 mm or more and 100 mm or less. The average length of the piezoelectric elements 4 in the short direction can be, for example, 10 mm or more and 80 mm or less. “Lower” means the attachment target side in a state where the sensor module 1 is attached to the attachment target. “Upper” means the opposite side.

  The pair of electrodes 5 a and 5 b are laminated on substantially the entire surface of both surfaces of the piezoelectric element 4. The pair of electrodes 5a and 5b is formed mainly of a conductive material such as metal. The “main component” refers to a component having the highest content, for example, a component having a content of 50% by mass or more.

  The support 3 is formed in a plate shape. The support 3 has a U-shaped notch in a plan view, and a band-shaped portion facing the notch constitutes a pair of support portions 6a and 6b that support the piezoelectric sensor 2 from below. The pair of support portions 6a and 6b support the piezoelectric sensor 2 on the upper surface. The pair of support portions 6a and 6b support the piezoelectric sensor 2 in a curved shape above the notches. The support 3 supports the piezoelectric sensor 2 so as to bend like a bow in a direction opposite to the pair of support portions 6a and 6b. Further, the support 3 supports the piezoelectric sensor 2 so that the piezoelectric sensor 2 protrudes upward most in the middle portion of the pair of support portions 6a and 6b. Since the sensor module 1 is notched between the pair of support portions 6a and 6b, the piezoelectric sensor 2 can easily detect sound incident from below through the notch, and the sound detection sensitivity is further increased. be able to.

  The material for forming the support 3 is not particularly limited as long as the piezoelectric sensor 2 can be supported sufficiently stably. Examples thereof include wood, metal, brass, synthetic resin, and ceramic.

  The average thickness of the support tool 3 can be reduced in weight so that it is not difficult to carry the instrument when the support tool 3 is attached to the instrument, and the rigidity is maintained so that it cannot be easily deformed by an external force. The thickness is not particularly limited as long as the thickness can be adjusted, and can be, for example, about 0.8 mm to 2 mm.

  The pair of support portions 6a and 6b have substantially the same thickness. The pair of support portions 6 a and 6 b directly support both opposing ends of the piezoelectric sensor 2. The upper surfaces of the pair of support portions 6a and 6b and the lower surfaces of the opposite ends of the piezoelectric sensor 2 are bonded with an adhesive. In the sensor module 1, if the piezoelectric sensor 2 is curved too much, the rigidity of the members stacked on the piezoelectric element 4, such as the pair of electrodes 5 a, 5 b, increases, and the binding force to the piezoelectric element 4 increases. A peak dip may occur in the frequency characteristics, and the sound detection accuracy may be insufficient. In this respect, the sensor module 1 supports the both ends of the piezoelectric sensor 2 in the longitudinal direction by the support 3 so that the curved shape of the piezoelectric sensor 2 can be maintained relatively gently. Easy to improve detection accuracy.

  The pair of support portions 6a and 6b are arranged such that opposing side surfaces are parallel to each other. The bending axis of the piezoelectric sensor 2 is parallel to the opposing side surfaces of the pair of support portions 6a and 6b. The pair of support portions 6 a and 6 b support the lower surfaces of the opposite ends of the piezoelectric sensor 2 across both ends in a direction parallel to the curved axis. The facing direction of the pair of support portions 6a and 6b and the side edge perpendicular to the bending axis of the piezoelectric sensor 2 are parallel to each other. The pair of support portions 6a and 6b support the piezoelectric sensor 2 so that the cross section perpendicular to the bending axis of the piezoelectric sensor 2 is kept the same. That is, the piezoelectric sensor 2 is not curved in a direction parallel to the opposing side surfaces of the pair of support portions 6a and 6b.

  The average distance between the pair of support portions 6a and 6b is that the restraining force on the piezoelectric element 4 becomes too high due to the rigidity of the members stacked on the piezoelectric element 4 such as the pair of electrodes 5a and 5b. This is not particularly limited as long as it is an interval that can stably hold the piezoelectric sensor 2 in a curved shape, and can be, for example, about 5 mm to 10 cm.

  The lower limit of the average radius of curvature of the outer periphery of the curved portion of the piezoelectric sensor 2 is preferably 10 cm, and more preferably 12 cm. On the other hand, the upper limit of the average radius of curvature of the outer periphery of the curved portion of the piezoelectric sensor 2 is preferably 20 cm, and more preferably 18 cm. If the average radius of curvature is less than the lower limit, directivity occurs in the piezoelectric element 4 and the sound detection accuracy may be reduced. On the other hand, if the average radius of curvature exceeds the upper limit, the posture of the piezoelectric sensor 2 may not be stably maintained. The “average radius of curvature” refers to an average value of the curvature radii of arbitrary five points extracted at equal intervals in the bending direction.

Support for the secondary moment I _{1 in the} direction perpendicular to the bending axis of the region between the pair of support portions 6a and 6b of the piezoelectric sensor 2 in the state attached to the support 3 (opposite direction of the pair of support portions 6a and 6b). The lower limit of the ratio (I ₀ / I ₁ ) of the sectional second moment I _{0 in} the same direction as that of the region of the piezoelectric sensor 2 in a state where it is not attached to the tool 3 is preferably 0.015, and 0.03 Is more preferable. On the other hand, the upper limit of the ratio (I ₀ / I ₁ ) is preferably 0.14, and more preferably 0.11. If the ratio is less than the lower limit, the piezoelectric sensor 2 is excessively curved, thereby causing directivity in the piezoelectric element 4 and reducing the sound detection accuracy. Conversely, when the ratio exceeds the upper limit, the degree of bending of the piezoelectric sensor 2 becomes insufficient, and the posture of the piezoelectric sensor 2 may not be stably maintained.

<Stringed instruments>
3 and 4 includes a hollow body 13 having a soundboard 12, a bridge 15 provided on the outer surface side of the soundboard 12 and supporting a plurality of strings 14, and a saddle provided on the outer surface of the bridge 15. 16, a neck 17 connected to the body 13 and extending from one end side of the soundboard 12, and a head 18 provided on one end side of the neck 17 are mainly provided. The plurality of strings 14 are locked with a plurality of pegs 19 provided on the head 18 with one end wound around and locked to the plurality of pins 20 with the other end supported by the bridge 15 via the saddle 16. Has been. The sound board 12 has a sound hole 21 between the other end of the neck 17 and the bridge 15.

  As shown in FIG. 4, a plurality of sounding bars 22 are attached to the inner surface of the sounding board 12. In addition, on the inner surface of the soundboard 12, a plate 23 disposed at a position facing the bridge 15 with the soundboard 12 interposed therebetween, and a reinforcing plate 24 for reinforcing the strength of the soundboard 12 are provided. Furthermore, the sensor module 1 of FIG. 1 according to the present invention is attached to the inner surface of the soundboard 12. The stringed instrument 11 is configured as an electric acoustic guitar that converts the resonance sound of the body 13 into an electric signal by the sensor module 1 and outputs the electric signal.

  The sensor module 1 is attached to the inner surface of the soundboard 2 with the lower surface of the support 3 in contact with the inner surface of the soundboard 12. A method of attaching the support 3 to the inner surface of the soundboard 12 is not particularly limited, and for example, it can be attached using a known adhesive.

<Advantages>
The piezoelectric sensor 2 included in the sensor module 1 includes a sheet-like piezoelectric element 4, and the piezoelectric element 4 does not have directivity in a state before bending. Therefore, the sensitivity of the piezoelectric element 4 does not change greatly depending on from which direction the sound is incident before the bending. Therefore, it is possible to use the piezoelectric sensor 2 as a high-sensitivity microphone by stably holding the piezoelectric element 4 in a state where there is as little as possible an object that prevents the sound from entering the piezoelectric element 4. However, since the piezoelectric sensor 2 has low rigidity, it is difficult to stably hold it in the air. On the other hand, according to the knowledge of the present inventors, the piezoelectric element 4 does not change greatly in sensitivity even when it is bent to a certain extent. The sensor module 1 is made on the basis of such knowledge, and the piezoelectric sensor 2 is supported in a curved shape by the support 3 so that sound is sufficiently incident on the piezoelectric element 4. Can be stably held in the air, whereby the piezoelectric sensor 2 is used as a high sensitivity microphone.

  In the sensor module 1, the piezoelectric sensor 2 is supported in a curved shape by a support tool 3, and in detail, since the piezoelectric sensor 2 is supported in a curved state at both ends, at least a part of the piezoelectric sensor 2 is curved and in the air. Retained. Therefore, the portion held in the air of the piezoelectric sensor 2 is not easily affected by the vibration of the vibration surface, so that sound can be detected accurately. In addition, for example, if the piezoelectric sensor is supported on the support in a flat film shape, the tension on the piezoelectric sensor increases, which may cause a decrease in sensitivity of the piezoelectric sensor and a deterioration in frequency characteristics. This may cause variations in sensitivity. On the other hand, in the sensor module 1, since the piezoelectric sensor 2 is supported in a curved state by the support 3, it is difficult to apply tension to the piezoelectric sensor 2. Furthermore, in the sensor module 1, since the piezoelectric sensor 2 is supported in a curved state by the support 3, the posture of the piezoelectric sensor 2 is stabilized. Thereby, the sensor module 1 can suppress a decrease in sensitivity of the piezoelectric sensor 2 and can suppress variations in detection signals. Furthermore, the sensor module 1 can be used with being attached to the vibration surface, thereby reducing noise. Therefore, the sensor module 1 can easily and reliably detect the sound while maintaining the integrity with the musical instrument.

  Since the stringed instrument includes the sensor module 1, the resonance sound of the body 13 can be detected easily and reliably while maintaining integrity with the sensor module 1.

[Second Embodiment]
<Sensor module>
The sensor module 31 in FIG. 5 is configured to be attachable to the inner surface of the soundboard 12 of the stringed instrument 11 in FIG. 3 instead of the sensor module 1 in FIG. The sensor module 31 of FIG. 5 includes a film-like piezoelectric sensor 2 and a support 33 that supports the piezoelectric sensor 2 in a curved shape. The support 33 holds at least a part of the piezoelectric sensor 2 in the air in a curved state. The support tool 33 supports the piezoelectric sensor 2 in a both-sided manner. The sensor module 31 has the same configuration as the sensor module 1 of FIG. 1 except that the support 33 has low-rigidity portions 34a and 34b that reduce vibration transmission. Therefore, only the support tool 33 will be described below.

  In the support tool 33, a pair of low-rigidity parts 34a and 34b are laminated on the upper surfaces of the pair of support parts 6a and 6b in the support tool 3 of FIG. The piezoelectric sensor 2 is stacked on a pair of low rigidity portions 34a and 34b. That is, in the sensor module 31, a pair of low-rigidity portions 34a and 34b are disposed between the piezoelectric sensor 2 of the sensor module 1 of FIG. 1 and the pair of support portions 6a and 6b. The pair of support portions 6a and 6b, the pair of low-rigidity portions 34a and 34b, and the piezoelectric sensor 2 are bonded by a known adhesive. Opposing side surfaces of the pair of low-rigidity portions 34a and 34b are arranged in parallel. The opposing side surfaces of the pair of low-rigidity portions 34a and 34b are flush with the opposing side surfaces of the pair of support portions 6a and 6b.

  The pair of low-rigidity portions 34a and 34b are formed in a plate shape. Further, the pair of low-rigidity parts 34a and 34b have substantially the same thickness. The specific configuration of the pair of low-rigidity portions 34a and 34b is not particularly limited as long as vibration transmission can be reduced. For example, a sheet mainly composed of an elastic material such as elastomer or rubber, or a porous resin sheet , Woven fabric, non-woven fabric and the like.

  The average thickness of the low-rigidity portions 34a and 34b is not particularly limited as long as the thickness can sufficiently reduce the transmission of vibration to the piezoelectric sensor 2 while stably supporting the piezoelectric sensor 2 by the support 33. For example, it can be 1 mm or more and 10 mm or less.

<Advantages>
The sensor module 31 has a pair of low-rigidity parts 34a and 34b in which the support 33 reduces vibration transmission, and the piezoelectric sensor 2 is stacked on the pair of low-rigidity parts 34a and 34b. It is possible to suppress vibration from being transmitted from 33 to the piezoelectric sensor 2. Therefore, the sensor module 31 can detect sound more accurately.

[Third embodiment]
<Sensor module>
The sensor module 41 shown in FIGS. 6 and 7 is configured to be attachable to the inner surface of the soundboard 12 of the stringed instrument 11 shown in FIG. 3 instead of the sensor modules 1 and 31 shown in FIGS. The sensor module 41 includes a film-like piezoelectric sensor 42 and a support 3 that supports the piezoelectric sensor 42 in a curved shape. The support 3 holds at least a part of the piezoelectric sensor 42 in the air in a curved state. The support 3 supports the piezoelectric sensor 42 in a both-sided manner.

  The piezoelectric sensor 42 is laminated on the piezoelectric element 4 via the sheet-like piezoelectric element 4, a pair of plate-like electrodes 5a and 5b laminated on both surfaces of the piezoelectric element 4, and the pair of electrodes 5a and 5b. The pair of protective layers 43a and 43b having a plane area larger than that of the piezoelectric element 4 and terminals (not shown) to which lead wires for outputting electric signals to the outside are connected. That is, the piezoelectric sensor 42 has the piezoelectric sensor 2 of the sensor module 1 of FIG. 1 as a main body, and a pair of protective layers 43a and 43b are laminated on both surfaces of the main body. The piezoelectric sensor 42 has flexibility. The piezoelectric element 4 is disposed in a region included in the outer edge of the pair of protective layers 43a and 43b in plan view. Since the piezoelectric element 4 and the pair of electrodes 5a and 5b in the piezoelectric sensor 42 are the same as those of the piezoelectric sensor 2 in FIG.

  The pair of protective layers 43a and 43b are formed in a substantially rectangular shape in plan view. The pair of protective layers 43a and 43b are transparent. The main components of the pair of protective layers 43a and 43b include polyethylene, polypropylene, cyclic polyolefin, polystyrene, acrylonitrile-styrene copolymer (AS resin), acrylonitrile-butadiene-styrene copolymer (ABS resin), polyvinyl chloride, Synthetic resins such as fluorine resin, polyamide, polyimide, acrylic resin, polycarbonate, and silicone resin can be used. The pair of protective layers 43a and 43b are laminated on the outer surfaces of the pair of electrodes 5a and 5b, for example, by a known laminating method.

  As a minimum of average thickness of protective layers 43a and 43b, 10 micrometers is preferred and 50 micrometers is more preferred. On the other hand, the upper limit of the average thickness of the protective layers 43a and 43b is preferably 1 mm, and more preferably 500 μm. If the average thickness of the protective layers 43a and 43b is less than the lower limit, the rigidity of the protective layers 43a and 43b becomes insufficient, and the piezoelectric element 4 may not be kept curved. On the other hand, if the average thickness of the protective layers 43a and 43b exceeds the upper limit, the rigidity of the protective layers 43a and 43b becomes too high, and the piezoelectric element 4 becomes difficult to deform, thereby detecting sound by the piezoelectric element 4. May be difficult.

  The lower limit of the flexural modulus of the protective layers 43a and 43b is preferably 0.1 MPa, and more preferably 1 MPa. On the other hand, the upper limit of the flexural modulus of the protective layers 43a and 43b is preferably 100 MPa, and more preferably 10 MPa. If the bending elastic modulus is less than the lower limit, the piezoelectric element 4 may be difficult to keep curved. On the other hand, when the bending elastic modulus exceeds the upper limit, the piezoelectric element 4 becomes difficult to deform, which may make it difficult to detect sound by the piezoelectric element 4. The “elastic modulus of the protective layer” refers to a value measured according to JIS-K7171: 2008.

  The support 3 has the same configuration as the support 3 of the sensor module 1 of FIG. The pair of support portions 6a and 6b support the piezoelectric sensor 2 on the upper surface. The support 3 supports the non-stacked portion of the piezoelectric element 4 in the pair of protective layers 43a and 43b. Specifically, the support 3 includes a pair of side edges (in this embodiment, a pair of sides on both ends in the longitudinal direction) of the pair of protective layers 43a and 43b facing each other by the pair of support portions 6a and 6b. The portion located outside the edge) is supported. The upper surfaces of the pair of support portions 6a and 6b and the lower surface of the protective layer 43b are bonded with an adhesive. The pair of support portions 6a and 6b support the piezoelectric sensor 42 in a curved shape above the above-described notches. The support 3 supports the piezoelectric sensor 42 so as to bend like a bow in a direction opposite to the pair of support portions 6a and 6b. In addition, the support 3 supports the piezoelectric sensor 42 so that the piezoelectric sensor 42 protrudes upward at the intermediate portion between the pair of support portions 6a and 6b. The pair of support portions 6a and 6b support the lower surfaces of the opposite ends of the piezoelectric sensor 42 across both ends in the direction parallel to the curved axis. The bending axis of the piezoelectric sensor 42 is parallel to the opposing side surfaces of the pair of support portions 6a and 6b. Further, the facing direction of the pair of support portions 6a and 6b and the side edge perpendicular to the bending axis of the piezoelectric element 4 are parallel to each other. The pair of support portions 6a and 6b support the piezoelectric sensor 2 so that the cross section perpendicular to the bending axis of the piezoelectric sensor 42 is kept the same.

Note that the average radius of curvature of the outer periphery of the curved portion of the piezoelectric sensor 42, the ratio of the length of the curved portion of the piezoelectric sensor 42 in the vertical direction to the average distance between the pair of support portions 6a and 6b, the cross section of the piezoelectric sensor 42 The secondary moment ratio (I ₀ / I ₁ ) can be the same as that of the sensor module 1 of FIG.

<Advantages>
In the sensor module 41, since the support 3 supports the non-stacked portion of the piezoelectric element 4 in the pair of protective layers 43 a and 43 b, the vibration of the vibration surface can be suppressed from being transmitted to the piezoelectric element 4. Therefore, the sensor module 41 can detect sound more accurately. Further, the sensor module 41 can hold the entire piezoelectric element 4 in the air by the support 3 supporting the non-laminated portion of the piezoelectric element 4 in the pair of protective layers 43a and 43b. Can efficiently detect sound.

[Fourth embodiment]
<Sensor module>
The sensor module 51 of FIGS. 8 and 9 is configured to be attachable to the inner surface of the soundboard 12 of the stringed instrument 11 of FIG. 3 instead of the sensor modules 1, 31, 41 of FIGS. The sensor module 51 includes a film-like piezoelectric sensor 52 and a support 53 that supports the piezoelectric sensor 52 in a curved shape. The support 53 holds at least a part of the piezoelectric sensor 52 in the air in a curved state. The support 53 supports the piezoelectric sensor 52 in a double-sided manner.

  The piezoelectric sensor 52 is laminated on the piezoelectric element 54 via the sheet-like piezoelectric element 54, a pair of plate-like electrodes 55a and 55b laminated on both surfaces of the piezoelectric element 54, and the pair of electrodes 55a and 55b. The pair of protective layers 56a and 56b having a plane area larger than that of the piezoelectric element 54 and terminals (not shown) to which lead wires for outputting electric signals to the outside are connected. The piezoelectric sensor 52 has flexibility. In the piezoelectric sensor 52, the piezoelectric element 54 and the pair of electrodes 55a and 55b have a pair of convex portions 57a and 57b that protrude outward from the pair of opposing side edges, and the pair of convex portions 57a in a plan view. , 57b have a pair of positioning holes 58a, 58b penetrating in the thickness direction. In the piezoelectric sensor 52, the piezoelectric element 54 and the pair of electrodes 55a and 55b have a pair of convex portions 57a and 57b, and the piezoelectric element 54, the pair of electrodes 55a and 55b, and the pair of protective layers 56a and 56b are a pair. Except for the positioning holes 58a and 58b, the configuration is the same as that of the piezoelectric sensor 2 of FIG.

  The support tool 53 includes a main body 59 and a pair of screws 60a and 60b. The main body 59 is formed in a plate shape. The main body 59 has a U-shaped notch in plan view, and portions facing each other across the notch constitute a pair of support portions 61a and 61b that support the piezoelectric sensor 52 from below. The main body 59 has the same configuration as that of the support 3 in FIG. 1 except that a pair of screw holes are formed in portions overlapping the pair of positioning holes 58a and 58b in a state where the piezoelectric sensor 52 is attached to the pair of support portions 61a and 61b. Have

  The pair of support portions 61a and 61b support the piezoelectric sensor 52 in a curved shape above the notches. The support tool 53 supports the piezoelectric sensor 52 so as to bend in a bow shape in the facing direction of the pair of support portions 61a and 61b. In addition, the support tool 53 supports the piezoelectric sensor 52 so that the piezoelectric sensor 52 protrudes upward most in the middle portion of the pair of support portions. The bending axis of the piezoelectric sensor 52 is parallel to the opposing side surfaces of the pair of support portions 61a and 61b. The opposing direction of the pair of support portions 61a and 61b and the side edge perpendicular to the bending axis of the piezoelectric element 4 are parallel to each other. The pair of support portions 61 a and 61 b support the piezoelectric sensor 52 so that the cross section perpendicular to the bending axis of the piezoelectric sensor 52 is kept the same.

  The pair of screws 60a and 60b are connected to the pair of positioning holes 58a and 58b. Specifically, the pair of screws 60a and 60b are inserted from the upper side of the pair of positioning holes 58a and 58b, and the distal end side is fixed to the pair of screw holes so that the piezoelectric sensor 52 is paired with the pair of support portions 61a and 61a. It fixes to 61b.

Note that the average radius of curvature of the outer periphery of the curved portion of the piezoelectric sensor 52, the ratio of the length of the curved portion of the piezoelectric sensor 52 in the vertical direction to the average distance between the pair of support portions 61a and 61b, the cross section of the piezoelectric sensor 52 The secondary moment ratio (I ₀ / I ₁ ) can be the same as that of the sensor module 1 of FIG.

<Advantages>
In the sensor module 51, the piezoelectric element 54 has a pair of positioning holes 58a and 58b, and the support 53 has a pair of screws 60a and 60b connected to the pair of positioning holes 58a and 58b. The piezoelectric sensor 52 can be easily and reliably attached to the support member 53 using the pair of positioning holes 58a and 58b used for positioning. Further, in the sensor module 51, the pair of positioning holes 58a and 58b are formed in the pair of convex portions 57a and 57b protruding outside the pair of side edges facing the piezoelectric element 54, and therefore, the pair of positioning holes 58a. , 58b are fixed so as to overlap the pair of support portions 61a, 61b, so that the entire sound detection region of the piezoelectric element 54 defined between the pair of convex portions 57a, 57b is opposed to the pair of support portions 61a, 61b. It can be held in the air while curving in the direction. Therefore, the sensor module 51 can detect sound more accurately.

[Other Embodiments]
In addition, the sensor module according to the present invention can be implemented in a mode in which various changes and modifications are made in addition to the above mode. For example, in the sensor module, the support may support the piezoelectric sensor in a cantilever manner. In the sensor module, the support tool supports the piezoelectric sensor in a cantilever shape or a double-support shape, and the piezoelectric sensor is supported in a curved shape by the support tool, so that the sound is easily and reliably detected as described above. be able to. With reference to FIG.10 and FIG.11, the structure in which a support tool supports a piezoelectric sensor in a cantilever shape is demonstrated.

  10 and 11 includes a film-like piezoelectric sensor 2 and a support 73 that supports the piezoelectric sensor 2 in a curved shape. The support tool 73 holds at least a part of the piezoelectric sensor 2 in the air in a curved state. The support tool 73 supports the piezoelectric sensor 2 in a cantilever manner. The piezoelectric sensor 2 of the sensor module 71 is the same as the piezoelectric sensor 2 of the sensor module 1 of FIG.

  The support tool 73 is formed in a plate shape. The support tool 73 has a U-shaped notch in plan view, and portions facing each other across the notch constitute a pair of support portions 74 a and 74 b that support the piezoelectric sensor 2 from below.

  The pair of support portions 74a and 74b support the lower surfaces of the opposite ends of the piezoelectric sensor 2 in a direction parallel to the curved axis. The pair of support portions 74 a and 74 b support only one side in the direction parallel to the curved axis of the lower surface of the opposite ends of the piezoelectric sensor 2. Accordingly, in the sensor module 71, the support tool 73 supports the piezoelectric sensor 2 in a cantilever manner.

  The pair of support portions 74a and 74b support the piezoelectric sensor 2 in a curved shape above the notches. The pair of support portions 74a and 74b are arranged such that opposite side surfaces are parallel to each other. The support tool 73 supports the piezoelectric sensor 2 so as to bend in a bow shape in a direction opposite to the pair of support portions 74a and 74b. The upper surfaces of the pair of support portions 74a and 74b and the lower surfaces of the opposite ends of the piezoelectric sensor 2 are bonded with an adhesive. The support tool 73 supports the piezoelectric sensor 2 so that the piezoelectric sensor 2 protrudes upward at the middle part of the pair of support portions 74a and 74b. The bending axis of the piezoelectric sensor 2 is parallel to the opposing side surfaces of the pair of support portions 74a and 74b. The opposing direction of the pair of support portions 74a and 74b and the side edge perpendicular to the bending axis of the piezoelectric sensor 2 are parallel to each other.

  In the sensor module 71, the piezoelectric sensor 2 is supported in a cantilevered manner by the curved body by the support tool 73, so that the sound can be detected easily and reliably.

  The sensor module according to the present invention can be used by combining the configurations of the plurality of embodiments described above. For example, the support in the third embodiment, the fourth embodiment, and other embodiments may have a low-rigidity portion that reduces vibration transmission. In the first embodiment, the second actual form, and other embodiments, the piezoelectric element may have a positioning hole, and the support may have a screw connected to the positioning hole.

  The configuration of the support is not particularly limited. The support may be, for example, a plate-like member having openings inside and supporting both ends of the piezoelectric sensor by both ends of the openings. The support may be a pair of rod-like members that support both ends of the piezoelectric sensor. However, it is preferable that the support is formed from a single member because the curved shape of the piezoelectric sensor can be kept unchanged. Moreover, the said support tool may be comprised as an inclined surface where the upper surface of a pair of support part protruded toward the opposing direction. According to such a configuration, the piezoelectric sensor can be easily held like a bow, and the curved shape of the piezoelectric sensor can be easily maintained. Furthermore, the opposing surfaces of the pair of support portions are not necessarily arranged in parallel.

  The piezoelectric sensor may be curved in a direction parallel to the pair of edges in addition to the opposing direction of the pair of edges supported by the pair of support portions. However, it is preferable that the piezoelectric sensor does not change its curved shape in a direction parallel to the pair of edges supported by the pair of support portions from the viewpoint of suppressing the directivity from being generated in the piezoelectric element.

  The protective layer is not necessarily laminated on both sides of the piezoelectric element, and may be laminated only on one side of the piezoelectric element. The protective layer may not be laminated on the entire surface of the piezoelectric element as long as the part supported by the support is a non-laminated part of the piezoelectric element.

  The piezoelectric element need not have only a pair of positioning holes. For example, the piezoelectric element may have a plurality of positioning holes on opposite edge sides of the piezoelectric element.

  The planar shape of the piezoelectric sensor is not particularly limited. Further, in the above-described embodiment, the configuration in which the support tool supports both ends in the longitudinal direction of the piezoelectric sensor has been described. However, even when the piezoelectric sensor has a rectangular shape in plan view, the support tool is short of the piezoelectric sensor. You may support the both ends of a direction.

  The sensor module does not necessarily have to be attached to an electric acoustic guitar. The sensor module may be attached to various stringed instruments such as classical guitar, violin, cello, mandolin, and piano, or may be attached to instruments other than stringed instruments such as percussion instruments. Moreover, the attachment location of the sensor module is not particularly limited, and can be attached to an arbitrary vibration surface of the musical instrument.

  As described above, the sensor module according to the present invention is suitable as a pickup for musical instruments because it can detect sound easily and reliably.

1, 31, 41, 51, 71 Sensor module 2, 42, 52 Piezo sensor 3, 33, 53, 73 Support 4, 54 Piezoelectric element 5a, 5b, 55a, 55b Electrode 6a, 6b, 61a, 61b, 74a, 74b Support part 11 String instrument 12 Sound board 13 Body 14 String 15 Bridge 16 Saddle 17 Neck 18 Head 19 Peg 20 Pin 21 Sound hole 22 Sound bar 23 Plate 24 Reinforcement plate 34a, 34b Low rigidity parts 43a, 43b, 56a, 56b Protective layer 57a, 57b Convex part 58a, 58b Positioning hole 59 Body 60a, 60b Screw

Claims (6)

  A sensor module comprising a film-like piezoelectric sensor and a support that supports the piezoelectric sensor in a curved shape.   The sensor module according to claim 1, wherein an average radius of curvature of an outer periphery of the curved portion of the piezoelectric sensor is 10 cm or more and 20 cm or less.   The sensor module according to claim 1, wherein the support has a low-rigidity portion that reduces transmission of vibration, and the piezoelectric sensor is stacked on the low-rigidity portion.   The piezoelectric sensor has a piezoelectric element and a protective layer laminated on the piezoelectric element and has a larger planar area than the piezoelectric element, and the support supports a non-laminated portion of the piezoelectric element in the protective layer. The sensor module according to claim 1, claim 2, or claim 3.   5. The sensor module according to claim 1, wherein the piezoelectric element has a plurality of positioning holes, and the support has a plurality of screws connected to the plurality of positioning holes. 6.   The sensor module according to any one of claims 1 to 5, wherein the piezoelectric sensor has a substantially rectangular shape in a plan view, and the support supports both ends of the piezoelectric sensor in the longitudinal direction.

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