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WO2018168168A1 - Unité de capteur - Google Patents

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Publication number
WO2018168168A1
WO2018168168A1 PCT/JP2017/047381 JP2017047381W WO2018168168A1 WO 2018168168 A1 WO2018168168 A1 WO 2018168168A1 JP 2017047381 W JP2017047381 W JP 2017047381W WO 2018168168 A1 WO2018168168 A1 WO 2018168168A1
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WO
WIPO (PCT)
Prior art keywords
piezoelectric element
pair
shield
sensor unit
electrode
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2017/047381
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English (en)
Japanese (ja)
Inventor
智矢 宮田
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Yamaha Corp
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Yamaha Corp
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Filing date
Publication date
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Publication of WO2018168168A1 publication Critical patent/WO2018168168A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R17/00—Piezoelectric transducers; Electrostrictive transducers
    • H04R17/02—Microphones
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/30—Piezoelectric or electrostrictive devices with mechanical input and electrical output, e.g. functioning as generators or sensors
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10H—ELECTROPHONIC MUSICAL INSTRUMENTS; INSTRUMENTS IN WHICH THE TONES ARE GENERATED BY ELECTROMECHANICAL MEANS OR ELECTRONIC GENERATORS, OR IN WHICH THE TONES ARE SYNTHESISED FROM A DATA STORE
    • G10H3/00—Instruments in which the tones are generated by electromechanical means
    • G10H3/12—Instruments in which the tones are generated by electromechanical means using mechanical resonant generators, e.g. strings or percussive instruments, the tones of which are picked up by electromechanical transducers, the electrical signals being further manipulated or amplified and subsequently converted to sound by a loudspeaker or equivalent instrument
    • G10H3/14—Instruments in which the tones are generated by electromechanical means using mechanical resonant generators, e.g. strings or percussive instruments, the tones of which are picked up by electromechanical transducers, the electrical signals being further manipulated or amplified and subsequently converted to sound by a loudspeaker or equivalent instrument using mechanically actuated vibrators with pick-up means
    • G10H3/18—Instruments in which the tones are generated by electromechanical means using mechanical resonant generators, e.g. strings or percussive instruments, the tones of which are picked up by electromechanical transducers, the electrical signals being further manipulated or amplified and subsequently converted to sound by a loudspeaker or equivalent instrument using mechanically actuated vibrators with pick-up means using a string, e.g. electric guitar

Definitions

  • the present invention relates to a sensor unit.
  • a strain sensor that includes a sheet-like piezoelectric element and is attached to an acoustic device or the like to detect sound or vibration is known.
  • the piezoelectric element has a piezoelectric film and a pair of electrodes disposed on both sides of the piezoelectric film.
  • This strain sensor is configured such that a piezoelectric film is deformed by sound waves or vibrations to generate electric charges by a piezoelectric effect, and the electric charges can be taken out as a voltage signal by a pair of electrodes.
  • Such a strain sensor is often provided with shield layers on both sides of the piezoelectric element in order to prevent the piezoelectric element from picking up external noise (see JP-A-8-75575).
  • the shield layer is fixed to the entire outer surfaces of the pair of electrodes via the protective layer.
  • the shield layer since the shield layer is fixed to the entire outer surfaces of the pair of electrodes, the shield layer may affect the resonance of the piezoelectric film.
  • the shield layer in a strain sensor that detects sound waves, if the shield layer is fixed to the entire outer surfaces of a pair of electrodes, deformation of the piezoelectric film is likely to be hindered, and the characteristics of the sensor are likely to be affected.
  • the strain sensor may be handled in a bent state.
  • the shield layer is fixed to the entire outer surface of the pair of electrodes, the shield layer and the adhesive surface of the electrode or the electrode and the piezoelectric film
  • the adhesive surface may peel off unintentionally.
  • the adhesive surface between the electrode and the piezoelectric film is peeled off, noise may be mixed and the sensor function may be lost.
  • This invention is made based on such a situation, and makes it a subject to provide the sensor unit excellent in detection accuracy.
  • the present invention which has been made to solve the above problems, includes a sheet-like piezoelectric element and a pair of sheet-like shield portions that are disposed on both sides of the piezoelectric element in the thickness direction and are partially fixed to the piezoelectric element. It is a sensor unit provided with.
  • FIG. 6 is a schematic cross-sectional view showing a modification of the shield layer of the sensor unit in FIG. 1.
  • a sensor unit includes a sheet-shaped piezoelectric element and a pair of sheet-shaped shield portions that are disposed on both sides in the thickness direction of the piezoelectric element and are partially fixed to the piezoelectric element. It is a sensor unit provided.
  • the pair of shield portions are partially fixed to the piezoelectric element, and since these shield portions are not completely fixed to the piezoelectric element, the effect of the pair of shield portions on the resonance of the piezoelectric element. Can be reduced. Therefore, the sensor unit is excellent in detection accuracy.
  • spacers are provided on both sides of the piezoelectric element in plan view to hold the pair of shield portions in a separated state.
  • a space may be provided between the piezoelectric element and the pair of shield portions.
  • the piezoelectric element includes a signal electrode laminated on one side in the thickness direction, and the shield portion disposed on the signal electrode side is laminated on the inner side of the insulating layer and the insulating layer, It is preferable to have conductive layers that are connected to each other.
  • the detection area of the piezoelectric element is not fixed to the pair of shield portions.
  • the shield part is “partially fixed to the piezoelectric element” means that the shield part is piezoelectric, for example, via a lead wire, in addition to the case where the shield part is directly fixed to the piezoelectric element. This includes cases where the element is indirectly fixed to the element.
  • “Piezoelectric element detection area” refers to a certain area partitioned in the sheet surface of a piezoelectric element provided for detecting sound or vibration, for example, an area overlapping a pair of electrodes in plan view of the piezoelectric element. The area excluding the connection area with the lead wire.
  • the sensor unit 1 of FIG. 1 includes a sheet-like piezoelectric element 2 and a pair of sheet-like shield portions 3a and 3b disposed on both sides of the piezoelectric element 2 in the thickness direction.
  • the piezoelectric element 2 includes a piezoelectric film 11, a first electrode 12 laminated on one surface of the piezoelectric film 11, and a surface on the other side of the piezoelectric film 11 (opposite to the side on which the first electrode 12 is laminated). And a second electrode 13 stacked on the substrate.
  • the pair of shield portions 3a and 3b includes insulating layers 14a and 14b and a shield layer 15 laminated on the outer surface side of the insulating layers 14a and 14b (the side opposite to the side where the piezoelectric element 2 is disposed).
  • the sensor unit 1 is connected to the first electrode 12 and outputs a first lead wire 16a that outputs an electric signal to the outside.
  • the sensor unit 1 is connected to the second electrode 13 and outputs a second lead wire 16b that outputs an electric signal to the outside. And have.
  • the first lead wire 16a and the second lead wire 16b are electrically connected to an external detection circuit (not shown) at the end opposite to the side connected to the first electrode 12 and the second electrode 13. .
  • the sensor unit 1 is used, for example, by being attached to an acoustic device or the like, and is configured as a distortion sensor that detects sound and vibration.
  • the piezoelectric element 2 has flexibility.
  • the piezoelectric element 2 is configured to be deformable by a sound wave or vibration that is incident on the piezoelectric film 11 in the thickness direction, and thereby configured to detect sound or vibration.
  • the piezoelectric element 2 has a detection region X for detecting sound or vibration.
  • the piezoelectric element 2 is formed on the detection region X having a rectangular shape in plan view and on both outer sides in the longitudinal direction in the plan view of the detection region X, and includes a pair of electrodes 12 and 13 and a pair of electrodes. And a pair of connection regions (first connection region Y1 and second connection region Y2) to which the lead wires 16a and 16b are connected.
  • the piezoelectric element 2 is partially fixed to the shield portions 3a and 3b via the first lead wire 16a and the second lead wire 16b in the connection regions Y1 and Y2. That is, in the sensor unit 1, the detection region X is not fixed to the pair of shield portions 3a and 3b. In the sensor unit 1, since the detection region X is not fixed to the pair of shield portions 3a and 3b, the influence of the pair of shield portions 3a and 3b on the deformation of the detection region X can be easily and reliably removed. As a result, the sound or vibration detection accuracy can be significantly increased.
  • the piezoelectric film 11 is configured to be deformable by sound waves or vibration.
  • a specific configuration of the piezoelectric film 11 a known configuration such as one that bends and deforms due to sound waves or vibration and one that undergoes compression deformation can be employed.
  • the piezoelectric film 11 is disposed on the first electrode 12 side, and the negatively charged side is disposed on the second electrode 13 side.
  • the piezoelectric film 11 is formed in a strip shape in which the first connection region Y1 and the second connection region Y2 constitute both ends in the longitudinal direction.
  • the average thickness of the piezoelectric film 11 can be, for example, 30 ⁇ m or more and 150 ⁇ m or less.
  • the average length in the longitudinal direction of the piezoelectric film 11 can be set to, for example, 20 mm or more and 100 mm or less.
  • the average length of the piezoelectric film 11 in the short direction can be, for example, 10 mm or more and 80 mm or less.
  • the first electrode 12 and the second electrode 13 are laminated on substantially the entire surface of the piezoelectric film 11 in the thickness direction.
  • the first electrode 12 and the second electrode 13 are 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 first electrode 12 constitutes a signal electrode
  • the second electrode 13 constitutes a ground electrode.
  • the sensor unit 1 generates electric charges due to deformation of the piezoelectric film 11.
  • the sensor unit 1 is configured to be able to detect sound and vibration by measuring the potential of the first electrode 12 using the second electrode 13 as a reference potential.
  • the pair of shield portions 3a and 3b are partially fixed to the piezoelectric element 2, respectively. Specifically, the pair of shield portions 3a and 3b are connected to the piezoelectric element 2 via the first lead wire 16a and the second lead wire 16b so as to restrict the movement of the piezoelectric element 2 in the planar direction (direction parallel to the thickness direction). Partially fixed to.
  • the region that is not fixed to the pair of shield portions 3a and 3b of the piezoelectric element 2 is a non-bonded region that is not bonded to other members.
  • the pair of shield portions 3a and 3b has flexibility.
  • the pair of shield portions 3 a and 3 b is a two-layer structure of a shield layer 15 and insulating layers 14 a and 14 b that are directly laminated on the inner surface of the shield layer 15, and the inner surfaces of the insulating layers 14 a and 14 b are part of the piezoelectric element 2. Fixed.
  • the pair of shield portions 3a and 3b and the first lead wire 16a and the second lead wire 16b are fixed by a known adhesive or the like.
  • the lower limit of the average width of the fixed portion R of the piezoelectric element 11 and the pair of shield portions 3a and 3b is preferably 1 mm, and more preferably 2 mm.
  • the upper limit of the average width of the fixed portion R is preferably 5 mm, and more preferably 3 mm. If the average width is smaller than the lower limit, the adhesive strength of the fixed portion R may be insufficient. On the other hand, if the average width exceeds the upper limit, the fixed portion R becomes unnecessarily large, and it may be difficult to make the detection region X sufficiently large.
  • the upper limit of the ratio of the area of the fixed portion R to the area of the piezoelectric element 2 in plan view is preferably 0.3, more preferably 0.2, and even more preferably 0.1. If the ratio exceeds the upper limit, the fixed portion R becomes unnecessarily large, and the influence of the fixed portion R on the deformation of the piezoelectric element 11 may increase.
  • the lower limit of the ratio is not particularly limited as long as the positional deviation between the pair of shield portions 3a and 3b and the piezoelectric element 11 can be prevented, and may be set to 0.01, for example.
  • the shield portions 3a and 3b are arranged so as to cover the entire region of the detection region X in plan view. As described above, since the shield portions 3a and 3b cover the entire region of the detection region X in plan view, the influence of external noise can be easily and reliably removed.
  • the insulating layers 14a and 14b constitute innermost layers of the shield portions 3a and 3b.
  • the insulating layers 14a and 14b have flexibility.
  • the insulating layers 14a and 14b are formed with synthetic resin as a main component.
  • the synthetic resin include polyethylene, polypropylene, polyvinyl chloride, polycarbonate, polyester, polyamide, polyacetal, polyimide, and acrylic resin.
  • polyethylene terephthalate is preferable from the viewpoint of electrical characteristics, mechanical characteristics, cost, and the like.
  • the lower limit of the average thickness of the insulating layers 14a and 14b is preferably 0.1 ⁇ m, and more preferably 1 ⁇ m.
  • the upper limit of the average thickness of the insulating layers 14a and 14b is preferably 500 ⁇ m, and more preferably 100 ⁇ m. If the average thickness of the insulating layers 14a and 14b is less than the lower limit, the strength of the insulating layers 14a and 14b may be insufficient. On the other hand, if the average thickness of the insulating layers 14a and 14b exceeds the upper limit, the shield portions 3a and 3b may become unnecessarily thick or the flexibility of the shield portions 3a and 3b may be insufficient.
  • the shield layer 15 has conductivity.
  • the shield layer 15 constitutes the outermost layer of the shield portions 3a and 3b.
  • the shield layer 15 constituting the pair of shield portions 3a and 3b is composed of a single film member.
  • the shield layer 15 is formed of a band-shaped film member, and in a state where the longitudinal central portion of the film member is folded, one of the shield layers 15 is formed on the inner surface of the region on one side divided by the folded portion Z.
  • the insulating layer 14a is laminated, and the other insulating layer 14b is laminated on the inner surface of the other region.
  • the shield layer 15 has the second lead wire 16b in contact with the inner surface of the folded portion Z.
  • the shield layer 15 and the second lead wire 16b are bonded by solder, a conductive adhesive or the like. Thereby, the shield layer 15 is electrically connected to the second lead wire 16b.
  • the shield layer 15 is grounded and used to reduce the influence of external noise.
  • one insulating layer 14a and the other insulating layer 14b are formed as separate members, but one insulating layer serving as a pair of insulating layers 14a and 14b is formed on the inner surface of the shield layer 15. It may be laminated.
  • the shield layer 15 is formed mainly of metal.
  • the metal include silver, copper, gold, nickel, and aluminum.
  • the shield layer 15 is formed of, for example, a metal foil whose main component is the metal.
  • the pair of shield portions 3a and 3b is formed by, for example, applying a coating liquid containing a material for forming the pair of insulating layers 14a and 14b to the metal foil and then drying the pair of insulating layers 14a and 14b on the metal foil. It is formed by laminating 14b.
  • the lower limit of the average thickness of the shield layer 15 is preferably 0.01 ⁇ m, and more preferably 0.1 ⁇ m.
  • the upper limit of the average thickness of the shield layer 15 is preferably 500 ⁇ m, and more preferably 100 ⁇ m. If the average thickness is smaller than the lower limit, the shield layer 15 may be unintentionally torn. On the contrary, if the average thickness exceeds the upper limit, the shield portions 3a and 3b may become unnecessarily thick or the flexibility of the shield portions 3a and 3b may be insufficient.
  • the piezoelectric element 2 and the pair of shield portions 3a and 3b may be bonded by a known adhesive or the like, but the piezoelectric element 2 and the pair of shield portions 3a and 3b are preferably not bonded.
  • the sensor unit 1 can further suppress the influence of the pair of shield portions 3a and 3b on the deformation of the piezoelectric film 11 because the piezoelectric element 2 and the pair of shield portions 3a and 3b are not bonded.
  • the piezoelectric element 2 and the pair of shield portions 3a and 3b may be in close contact, but the piezoelectric element 2 and the pair of shield portions 3a. 3b is preferably provided. Since the sensor unit 1 has a space between the piezoelectric element 2 and the pair of shield portions 3 a and 3 b, the effect of the pair of shield portions 3 a and 3 b on the deformation of the piezoelectric film 11 can be further suppressed.
  • the lower limit of the ratio of the space area where the piezoelectric element 11 and the pair of shield portions 3a, 3b on the surface of the detection region X are not in close contact with the planar area of the detection region X is preferably 0.5, more preferably 0.7. 0.9 is more preferable.
  • the ratio is equal to or higher than the lower limit, it is easier to more accurately suppress the influence of the pair of shield portions 3a and 3b on the deformation of the piezoelectric film 11.
  • the upper limit of the ratio is not particularly limited and can be 1.0.
  • the pair of shield portions 3a and 3b may have a plurality of through holes (not shown) penetrating in the thickness direction.
  • the pair of shield portions 3a and 3b may expand outward due to thermal expansion of air existing in the space, The pair of shield portions 3a and 3b may be in close contact with the piezoelectric element 2 due to the cooling of the air.
  • the detection accuracy of sound and vibration may be reduced.
  • the sensor unit 1 has a plurality of through holes penetrating the pair of shield portions 3a and 3b in the thickness direction, so that the pair of shield portions 3a and 3b caused by the thermal expansion and cooling of the air. Swelling and close contact with the piezoelectric element 2 can be suppressed, and the detection accuracy of sound and vibration can be increased regardless of the use environment.
  • these through holes are preferably formed in a region that does not overlap the detection region X in plan view.
  • the average diameter of the plurality of through holes can be, for example, 100 ⁇ m or more and 5 mm or less. If the average diameter is less than the lower limit, there is a possibility that swelling of the pair of shield portions 3a and 3b and close contact with the piezoelectric element 2 cannot be sufficiently suppressed. Conversely, when the average diameter exceeds the upper limit, the plurality of through holes may affect the deformation of the piezoelectric film 11.
  • the first lead wire 16a and the second lead wire 16b are formed of, for example, a conductive linear conductor.
  • the first lead wire 16a has a bifurcated end opposite to the side connected to the detection circuit, and this branch portion is the first connection region Y1 and the second connection region Y2 and the outer surface of the first electrode 12. It is fixed to. Accordingly, the first lead wire 16a is electrically connected to the first electrode 12.
  • the second lead wire 16b has a bifurcated end opposite to the side connected to the detection circuit, and this branch portion is the second connection region Y1 in the first connection region Y1 and the second connection region Y2. It is fixed to the outer surface. Thereby, the second lead wire 16b is electrically connected to the second electrode 13.
  • the pair of shield portions 3 a and 3 b are partially fixed to the piezoelectric element 2, and the pair of shield portions 3 a and 3 b are not completely fixed to the piezoelectric element 2.
  • the influence of the portions 3a and 3b on the resonance of the piezoelectric element can be reduced. Therefore, the sensor unit 1 is excellent in detection accuracy.
  • the sensor unit 1 is excellent in detecting sound and vibration with high accuracy, and can particularly effectively improve sound detection accuracy.
  • the sensor unit 21 of FIG. 3 includes a sheet-like piezoelectric element 25 and a pair of sheet-like shield portions 3a and 3b disposed on both sides of the piezoelectric element 25 in the thickness direction.
  • the piezoelectric element 25 is partially fixed to the pair of shield portions 3a and 3b.
  • the piezoelectric element 25 has a piezoelectric film 26, a first electrode 27 stacked on one surface of the piezoelectric film 26, and a second electrode 28 stacked on the other surface of the piezoelectric film 26.
  • the pair of shield portions 3a and 3b includes insulating layers 14a and 14b and a shield layer 15 stacked on the outer surface side of the insulating layers 14a and 14b.
  • the sensor unit 21 is connected to the first electrode 27 and outputs a first lead wire 29a that outputs an electric signal to the outside.
  • the sensor unit 21 is connected to the second electrode 28 and outputs a second lead wire 29b that outputs an electric signal to the outside. And have.
  • the sensor unit 21 includes spacers 22a and 22b that hold the pair of shield portions 3a and 3b in a separated state on both sides of the piezoelectric element 25 in plan view.
  • the sensor unit 21 is used, for example, by being attached to an acoustic device or the like, and is configured as a distortion sensor that detects sound and vibration.
  • the pair of shield portions 3a and 3b in the sensor unit 21 are the same as the sensor unit 1 in FIG.
  • the piezoelectric element 25 has flexibility.
  • the piezoelectric element 25 is configured to be deformable by a sound wave or vibration that is incident on the piezoelectric film 26 in the thickness direction, and thereby configured to detect sound or vibration.
  • the piezoelectric element 25 has a detection region X for detecting sound or vibration.
  • the piezoelectric element 25 includes a detection region X having a rectangular shape in plan view, and a first connection region Y1 that protrudes outward from the detection region X in plan view and is connected to the first lead wire 29a. And a second connection region Y2 projecting outward from the detection region X in plan view and connected to the second lead wire 29b.
  • the first connection region Y1 and the second connection region Y2 protrude in opposite directions.
  • the piezoelectric element 25 can be configured in the same manner as the piezoelectric element 2 in FIG. 1 except that the shape is different.
  • the first lead wire 29a and the second lead wire 29b are formed of a linear conductor having conductivity, for example.
  • the first lead wire 29a is stacked on the outer surface of the first electrode 27 in the first connection region Y1, and is thereby electrically connected to the first electrode 27.
  • the second lead wire 29b is laminated on the outer surface of the second electrode 28 in the second connection region Y2, and is thereby electrically connected to the second electrode 28.
  • the spacers 22a and 22b are disposed so as to surround the piezoelectric element 25 in plan view.
  • Each of the spacers 22a and 22b has a pair of support surfaces disposed in parallel with the inner surfaces of the pair of shield portions 3a and 3b.
  • the spacers 22a and 22b are regions that do not overlap with the first lead wire 29a and the second lead wire 29b in a plan view, and the support surfaces are entirely on the inner surfaces of the pair of shield portions 3a and 3b. It arrange
  • the spacers 22a and 22b hold the pair of shield portions 3a and 3b in a state of being separated from each other at least on both sides of the piezoelectric element 25 in plan view.
  • the pair of shield portions 3a and 3b are held in a separated state.
  • the height of the spacers 22a and 22b is preferably equal to or greater than the maximum thickness of the piezoelectric element 25, and more preferably equal to the total thickness of the piezoelectric element 25 and the pair of lead wires 29a and 29b. Since the heights of the spacers 22a and 22b are equal to the total thickness of the piezoelectric element 25 and the pair of lead wires 29a and 29b, the spacers 22a and 22b are partially fixed to the pair of shield portions 3a and 3b. Are easily held in contact with the inner surfaces of the pair of shield portions 3a and 3b.
  • the material of the spacers 22a and 22b is not particularly limited, but may be a resin insulator that secures a space between the pair of shield portions 3a and 3b.
  • the spacers 22a and 22b may have adhesiveness to contribute to fixing the pair of shield portions 3a and 3b.
  • the spacers 22a and 22b may be made of a conductive metal. When the spacers 22a and 22b have conductivity, the shielding effect can be enhanced.
  • the sensor unit 21 is arranged so that the spacers 22a and 22b surround the piezoelectric element 25 in a plan view. Therefore, the spacer 22a and 22b can seal the outer region in the planar direction of the piezoelectric element 25. Thereby, it is possible to more reliably prevent external noise from entering the piezoelectric element 25 side.
  • the pair of shield portions 3a and 3b are partially fixed to the piezoelectric element 25 via the pair of lead wires 29a and 29b in the connection regions Y1 and Y2. Further, the inner surfaces of the pair of shield portions 3a and 3b are supported by the spacers 22a and 22b so as to surround the periphery of the piezoelectric element 25 in a region that does not overlap the first lead wire 29a and the second lead wire 29b in plan view. ing. Thereby, the detection region X of the piezoelectric element 25 is not fixed to the pair of shield portions 3a and 3b. Thereby, there is a space between the piezoelectric element 25 and the pair of shield portions 3a and 3b.
  • an air layer is formed between the entire area of the surface of the detection area X and the inner surfaces of the pair of shield portions 3a and 3b.
  • the ratio of the space area where the piezoelectric element 25 and the pair of shield portions 3 a and 3 b on the surface of the detection region X are not in close contact with the planar area of the detection region X is 1.
  • the sensor unit 21 can accurately remove the influence of the pair of shield portions 3a and 3b on the deformation of the detection region X.
  • the piezoelectric element 25 and the pair of shield portions 3a and 3b are fixed in a dot shape in the connection regions Y1 and Y2.
  • the lower limit of the average diameter of the fixed portion R of the piezoelectric element 25 and the pair of shield portions 3a and 3b is preferably 1 mm, and more preferably 2 mm.
  • the upper limit of the average diameter of the fixed portion R is preferably 5 mm, and more preferably 3 mm. If the average diameter is smaller than the lower limit, the adhesive strength of the fixed portion R may be insufficient. On the other hand, when the average diameter exceeds the upper limit, the influence of the fixed portion R on the deformation of the piezoelectric element 25 may increase.
  • the “average diameter” refers to a diameter converted into a perfect circle of equal area.
  • the “average diameter of the fixed portion” refers to the average diameter of the fixed portion in plan view.
  • the sensor unit 21 has spacers 22a and 22b that hold the pair of shield portions 3a and 3b in a separated state on both sides of the piezoelectric element 25 in a plan view. It is easy to increase the effect of reducing the influence of the piezoelectric element 25 on the deformation of the detection region X.
  • the sensor unit 31 of FIG. 5 includes a sheet-like piezoelectric element 25 and a pair of sheet-like shield portions 33a and 33b disposed on both sides of the piezoelectric element 25 in the thickness direction.
  • the piezoelectric element 25 is partially fixed to the pair of shield portions 33a and 33b.
  • the piezoelectric element 25 has a piezoelectric film 26, a first electrode 27 stacked on one surface of the piezoelectric film 26, and a second electrode 28 stacked on the other surface of the piezoelectric film 26.
  • the first electrode 27 constitutes a signal electrode
  • the second electrode 28 constitutes a ground electrode.
  • the piezoelectric element 25 has a signal electrode stacked on one side in the thickness direction and a ground electrode disposed on the other side in the thickness direction.
  • One shield portion 33a (the shield portion disposed on the first electrode 27 side of the piezoelectric element 25) includes the insulating layer 14a, the shield layer 15 laminated on the outer surface side of the insulating layer 14a, and the inner surface of the insulating layer 14a. And a conductive layer 34 stacked on the side.
  • the other shield part 33b shield part disposed on the second electrode 28 side of the piezoelectric element 25 has an insulating layer 14b and a shield layer 15 laminated on the outer surface side of the insulating layer 14b.
  • the sensor unit 31 is connected to the first electrode 27 and outputs an electric signal to the outside.
  • the second lead wire 29b is connected to the second electrode 28 and outputs an electric signal to the outside. And have.
  • the sensor unit 31 has spacers 22a and 22b that hold the pair of shield portions 33a and 33b in a separated state on both sides of the piezoelectric element 25 in plan view.
  • the sensor unit 31 is used, for example, by being attached to an acoustic device or the like, and is configured as a distortion sensor that detects sound and vibration.
  • the sensor unit 31 has the same configuration as the sensor unit 21 of FIG. 3 except that one shield portion 33a disposed on the signal electrode side includes a conductive layer 34 laminated on the inner surface side of the insulating layer 14a. Have. Therefore, only one shield part 33a will be described below.
  • one shield part 33a includes the insulating layer 14a, the shield layer 15 stacked on the outer surface side of the insulating layer 14a, and the conductive layer 34 stacked on the inner surface side of the insulating layer 14a.
  • One shield part 33 a is a three-layer structure of the insulating layer 14 a, the shield layer 15, and the conductive layer 34.
  • One shield part 33a has flexibility. Specific configurations of the insulating layer 14a and the shield layer 15 of the shield part 33a can be the same as those of the sensor unit 1 of FIG.
  • the conductive layer 34 constitutes the innermost layer of one shield part 33a.
  • the conductive layer 34 has conductivity.
  • the conductor layer 34 is held in an insulated state from the shield layer 15.
  • the conductive layer 34 is electrically connected to the first electrode 27 (signal electrode).
  • the conductive layer 34 is preferably disposed so as to cover the entire region on the surface side of the detection region X, and more preferably disposed so as to cover the entire region on the surface side of the piezoelectric film 26.
  • An air layer is preferably formed between the conductive layer 34 and the detection region X. The air layer is more preferably formed over the entire surface of the detection region X.
  • the conductive layer 34 is formed using, for example, a metal or a metal compound as a main component.
  • the metal include silver, copper, gold, nickel, aluminum, and carbon.
  • the metal compound include ITO.
  • the conductive layer 34 may be laminated on the inner surface of the insulating layer 14a by metal printing or metal vapor deposition, or may be laminated by adhering a metal foil to the inner surface of the insulating layer 14a.
  • the lower limit of the average thickness of the conductive layer 34 is preferably 0.01 ⁇ m, and more preferably 0.1 ⁇ m.
  • the upper limit of the average thickness of the conductive layer 34 is preferably 500 ⁇ m, and more preferably 100 ⁇ m.
  • the conductive layer 34 and the first electrode 27 may be electrically connected by bonding the conductive layer 34 and the first lead wire 29a with solder, a conductive adhesive, or the like.
  • the conductive layer 34 and the first electrode 27 may be electrically connected by forming the first lead wire 29a integrally with the conductive layer 34 continuously from the end of the conductive layer 34.
  • a shield portion 33 a disposed on the first electrode 27 side is laminated on the inner surface side of the insulating layer 14 a and the insulating layer 14 a, and the conductive layer 34 electrically connected to the first electrode 27 is provided. Therefore, the conductive layer 34 and the first electrode 27 can be kept at the same potential, and thus the generation of capacitance between the first electrode 27 and the conductive layer 34 can be suppressed. Therefore, the sensor unit 31 can suppress the influence of the electrostatic capacitance on the detection of sound and vibration, and can further increase the detection accuracy of sound and vibration.
  • the spacer may be provided only on both sides of the piezoelectric element in plan view.
  • the piezoelectric element is not necessarily fixed to the pair of shield portions via the lead wires, and for example, the outer surface of the electrode (that is, the outer surface of the detection region) may be directly fixed to the shield portion. Further, even when the piezoelectric element is fixed to the pair of shield portions via lead wires, the specific fixing method is not limited to the configuration of the above-described embodiment.
  • the sensor unit 41 includes a shield layer 45 having a conductive portion 43 b disposed outside the second electrode 42, and an insulating layer laminated on the inner surface of the shield layer 45. 44b and a conductive portion 44c having conductivity and penetrating the insulating layer 44b in the thickness direction, and the second lead wire 46b is electrically connected to the shield layer 45 via the conductive portion 44c. Also good.
  • the planar shape of the piezoelectric element is not particularly limited, and can be appropriately designed depending on the application. Further, the configurations of the above-described embodiments can be appropriately combined.
  • the sensor units 21 and 31 of FIGS. 3 and 5 can employ a configuration without the spacers 22a and 22b. And it is also possible to use a spacer in the sensor units 1 and 41 of FIG.
  • the shield layer 55 includes a pair of strip-shaped film members 55a disposed on both sides of the piezoelectric element, and ends on one side in the longitudinal direction of the pair of film members 55a. And a conductive member 55b that connects the two.
  • the connection method of a pair of film member 55a and the electrically-conductive member 55b is not specifically limited, For example, you may connect using a conductive tape and may connect using a screw.
  • the sensor unit can reduce the influence of the pair of shield parts on the resonance of the piezoelectric element by partially fixing the piezoelectric element and the pair of shield parts as described above.
  • the sensor unit may be stacked with a weight on the outer surface of the shield part as necessary.
  • a sheet-like weight having a synthetic resin as a main component may be laminated on the outer surface of the shield portion disposed on the first electrode side.
  • the sensor unit is configured by stacking a weight on the outer surface of the shield part disposed on the first electrode side.
  • the sensor unit can closely contact only the outer surface of the second electrode of the piezoelectric element and the inner surface of the shield portion disposed on the second electrode side. It is possible to facilitate transmission to the piezoelectric element.
  • the sensor unit can be used as a pickup for a musical instrument attached to a sound board of a stringed instrument, for example, a boundary microphone, a device for detecting abnormal noise or noise of a building, a machine, a transport aircraft, etc. It can also be used for members other than musical instruments.
  • the sensor unit of the present invention is suitable for being used as a pick-up for musical instruments such as stringed instruments because of its excellent sound and vibration detection accuracy.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Piezo-Electric Transducers For Audible Bands (AREA)

Abstract

La présente invention aborde le problème consistant à fournir une unité de capteur ayant une excellente précision de détection. L'unité de capteur de la présente invention est pourvue d'un élément piézoélectrique en forme de feuille et d'une paire de parties de blindage en forme de feuille disposées des deux côtés dans la direction de l'épaisseur de l'élément piézoélectrique et partiellement fixées à l'élément piézoélectrique. Il est préférable d'avoir un espaceur destiné à maintenir la paire de parties de blindage dans un état séparé sur les deux côtés dans une vue en plan de l'élément piézoélectrique. Il est préférable d'avoir un espace entre l'élément piézoélectrique et la paire de parties de blindage. Il est préférable que l'élément piézoélectrique soit pourvu d'une électrode de signal empilée sur l'un des côtés dans la direction de l'épaisseur, et que la partie de blindage disposée sur le côté d'électrode de signal comprenne une couche isolante et une couche conductrice empilées sur le côté de surface interne de la couche isolante et électriquement connectées à l'électrode de signal. Il est préférable qu'une région de détection de l'élément piézoélectrique ne soit pas fixée à la paire de parties de blindage.
PCT/JP2017/047381 2017-03-13 2017-12-28 Unité de capteur Ceased WO2018168168A1 (fr)

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JP2020134444A (ja) * 2019-02-25 2020-08-31 ロボセンサー技研株式会社 圧電センサ
CN112968123A (zh) * 2021-02-04 2021-06-15 电子科技大学 一种柔性薄膜式压电声发射传感器及其制作方法

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JPH01272294A (ja) * 1988-04-22 1989-10-31 Murata Mfg Co Ltd 骨導マイクロホン
JPH0875575A (ja) * 1994-09-02 1996-03-22 Matsushita Electric Ind Co Ltd 圧電センサ
JP2001291906A (ja) * 2000-04-07 2001-10-19 Matsushita Electric Ind Co Ltd 可撓性圧電素子
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JP2012212134A (ja) * 2011-03-24 2012-11-01 Yamaha Corp 楽器用振動センサ、ピックアップサドルおよび楽器
WO2016027708A1 (fr) * 2014-08-21 2016-02-25 株式会社村田製作所 Élément de conversion électromécanique et dispositif de présentation tactile
JP2017062200A (ja) * 2015-09-25 2017-03-30 積水化学工業株式会社 圧電センサ構造

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JPS53157000U (fr) * 1977-05-16 1978-12-09
JPH01272294A (ja) * 1988-04-22 1989-10-31 Murata Mfg Co Ltd 骨導マイクロホン
JPH0875575A (ja) * 1994-09-02 1996-03-22 Matsushita Electric Ind Co Ltd 圧電センサ
JP2001291906A (ja) * 2000-04-07 2001-10-19 Matsushita Electric Ind Co Ltd 可撓性圧電素子
JP2007507188A (ja) * 2003-09-29 2007-03-22 バング アンド オルフセン メディコム アーエス マイクロフォンコンポーネントおよびその製造方法
JP2012212134A (ja) * 2011-03-24 2012-11-01 Yamaha Corp 楽器用振動センサ、ピックアップサドルおよび楽器
WO2016027708A1 (fr) * 2014-08-21 2016-02-25 株式会社村田製作所 Élément de conversion électromécanique et dispositif de présentation tactile
JP2017062200A (ja) * 2015-09-25 2017-03-30 積水化学工業株式会社 圧電センサ構造

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JP2020134444A (ja) * 2019-02-25 2020-08-31 ロボセンサー技研株式会社 圧電センサ
JP7519065B2 (ja) 2019-02-25 2024-07-19 ロボセンサー技研株式会社 圧電センサ
CN112968123A (zh) * 2021-02-04 2021-06-15 电子科技大学 一种柔性薄膜式压电声发射传感器及其制作方法
CN112968123B (zh) * 2021-02-04 2022-11-04 电子科技大学 一种柔性薄膜式压电声发射传感器及其制作方法

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