WO2018168168A1 - Sensor unit - Google Patents

Sensor unit Download PDF

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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
Application number
PCT/JP2017/047381
Other languages
French (fr)
Japanese (ja)
Inventor
智矢 宮田
Original Assignee
ヤマハ株式会社
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Filing date
Publication date
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Publication of WO2018168168A1 publication Critical patent/WO2018168168A1/en

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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.

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  • Acoustics & Sound (AREA)
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Abstract

The present invention addresses the problem of providing a sensor unit having excellent detection accuracy. This sensor unit is provided with a sheet-shaped piezoelectric element, and a pair of sheet-shaped shield parts disposed on both sides in the thickness direction of the piezoelectric element and partially secured to the piezoelectric element. It is preferable to have a spacer for holding the pair of shield parts in a separated state on both sides in plan view of the piezoelectric element. It is preferable to have a space between the piezoelectric element and the pair of shield parts. It is preferable that the piezoelectric element is provided with a signal electrode stacked on one side thereof in the thickness direction, and that the shield part disposed on the signal electrode side comprises an insulating layer and a conductive layer stacked on the inner surface side of the insulating layer and electrically connected to the signal electrode. It is preferable that a detection region of the piezoelectric element is not secured to the pair of shield parts.

Description

センサーユニットSensor unit
　本発明は、センサーユニットに関する。 The present invention relates to a sensor unit.
　シート状の圧電素子を備え、音響機器等に取り付けられて音や振動を検出する歪みセンサーが知られている。この歪みセンサーは、前記圧電素子が、圧電膜とこの圧電膜の両面に配設される一対の電極を有する。この歪みセンサーは、圧電膜が音波や振動によって変形し圧電効果によって電荷を生じ、この電荷を一対の電極が電圧信号として取り出し可能に構成されている。 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. In this strain sensor, 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.
　このような歪みセンサーは、圧電素子が外部ノイズを拾うことを防止するため、圧電素子の両面側にシールド層が設けられることが多い（特開平８－７５５７５号公報参照）。この歪みセンサーは、シールド層が保護層を介して一対の電極の外面全面に固定されている。 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). In this strain sensor, the shield layer is fixed to the entire outer surfaces of the pair of electrodes via the protective layer.
特開平８－７５５７５号公報JP-A-8-75575
　しかしながら、前記従来の歪みセンサーは、シールド層が一対の電極の外面全面に固定されているため、シールド層が圧電膜の共振に影響を及ぼすおそれがある。特に、音波を検出する歪みセンサーにあっては、シールド層が一対の電極の外面全面に固定されていると圧電膜の変形が阻害されやすく、センサーの特性に影響を与えやすい。 However, in the conventional strain sensor, 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. In particular, 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.
　また今日においては、歪みセンサーを曲げた状態で取り扱うこともあり、この場合シールド層が一対の電極の外面全面に固定されていると、シールド層と電極の接着面、又は電極と圧電膜との接着面が意図せず剥離することがある。特に、電極と圧電膜との接着面が剥離すると、ノイズが混入するおそれに加え、センサーとしての機能が失われるおそれもある。 In addition, today, the strain sensor may be handled in a bent state. In this case, if 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. In particular, if the adhesive surface between the electrode and the piezoelectric film is peeled off, noise may be mixed and the sensor function may be lost.
　本発明は、このような事情に基づいてなされたものであり、検出精度に優れるセンサーユニットを提供することを課題とする。 This invention is made based on such a situation, and makes it a subject to provide the sensor unit excellent in detection accuracy.
　前記課題を解決するためになされた本発明は、シート状の圧電素子と、前記圧電素子の厚さ方向両側に配設され、この圧電素子に部分的に固定される一対のシート状のシールド部とを備えるセンサーユニットである。 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.
本発明の一実施形態に係るセンサーユニットを示す模式的断面図である。It is a typical sectional view showing the sensor unit concerning one embodiment of the present invention. 図１のセンサーユニットのシールド部の接続構造を説明するための模式的部分断面図である。It is a typical fragmentary sectional view for demonstrating the connection structure of the shield part of the sensor unit of FIG. 図１のセンサーユニットとは異なる形態に係るセンサーユニットを示す模式的断面図である。It is typical sectional drawing which shows the sensor unit which concerns on a different form from the sensor unit of FIG. 図３のセンサーユニットのシールド部の接続構造を説明するための模式的部分断面図である。It is a typical fragmentary sectional view for demonstrating the connection structure of the shield part of the sensor unit of FIG. 図１及び図３のセンサーユニットとは異なる形態に係るセンサーユニットを示す模式的断面図である。It is typical sectional drawing which shows the sensor unit which concerns on a different form from the sensor unit of FIG.1 and FIG.3. 図１、図３及び図５のセンサーユニットとは異なる形態に係るセンサーユニットを示す模式的断面図である。It is typical sectional drawing which shows the sensor unit which concerns on a different form from the sensor unit of FIG.1, FIG3 and FIG.5. 図１のセンサーユニットのシールド層の変形例を示す模式的断面図である。FIG. 6 is a schematic cross-sectional view showing a modification of the shield layer of the sensor unit in FIG. 1.
　本発明の一態様に係るセンサーユニットは、シート状の圧電素子と、前記圧電素子の厚さ方向両側に配設され、この圧電素子に部分的に固定される一対のシート状のシールド部とを備えるセンサーユニットである。 A sensor unit according to an aspect of the present invention 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.
　当該センサーユニットは、一対のシールド部が圧電素子に部分的に固定されており、これらのシールド部が圧電素子に全面的に固定されていないので、一対のシールド部が圧電素子の共振に及ぼす影響を低減することができる。そのため、当該センサーユニットは検出精度に優れる。 In the sensor unit, 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.
　前記圧電素子の平面視両側に、前記一対のシールド部を離間した状態で保持するスペーサを有するとよい。 It is preferable that spacers are provided on both sides of the piezoelectric element in plan view to hold the pair of shield portions in a separated state.
　前記圧電素子と一対のシールド部との間に空間を有するとよい。 A space may be provided between the piezoelectric element and the pair of shield portions.
　前記圧電素子が厚さ方向一方側に積層されるシグナル電極を備え、このシグナル電極側に配設される前記シールド部が、絶縁層及びこの絶縁層の内面側に積層され、前記シグナル電極と電気的に接続される導電層を有するとよい。 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.
　前記圧電素子の検出領域が前記一対のシールド部と固定されていないことが好ましい。 It is preferable that the detection area of the piezoelectric element is not fixed to the pair of shield portions.
　なお、本発明において、シールド部が「圧電素子に部分的に固定される」とは、シールド部が圧電素子に直接部分的に固定される場合の他、例えばリード線を介してシールド部が圧電素子に間接的に部分的に固定される場合も含む。「圧電素子の検出領域」とは、音又は振動を検出するために設けられた圧電素子のシート面内において区画される一定の領域をいい、例えば圧電素子の平面視において一対の電極と重なり合う領域であって、リード線との接続領域を除く領域をいう。 In the present invention, 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.
　以下、適宜図面を参照しつつ、本発明の実施の形態を詳説する。 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
［第一実施形態］
＜センサーユニット＞
　図１のセンサーユニット１は、シート状の圧電素子２と、圧電素子２の厚さ方向両側に配設される一対のシート状のシールド部３ａ、３ｂとを備える。圧電素子２は、圧電膜１１と、圧電膜１１の一方側の面に積層される第１電極１２と、圧電膜１１の他方側（第１電極１２が積層される側と反対側）の面に積層される第２電極１３とを有する。一対のシールド部３ａ、３ｂは、絶縁層１４ａ、１４ｂと、絶縁層１４ａ、１４ｂの外面側（圧電素子２が配設される側と反対側）に積層されるシールド層１５とを有する。また、当該センサーユニット１は、第１電極１２に接続され、外部に電気信号を出力する第１リード線１６ａと、第２電極１３に接続され、外部に電気信号を出力する第２リード線１６ｂとを有する。第１リード線１６ａ及び第２リード線１６ｂは、第１電極１２及び第２電極１３と接続される側と反対側の端部が外部の検出回路（不図示）に電気的に接続されている。当該センサーユニット１は、例えば音響機器等に取り付けられて用いられ、音や振動を検出する歪みセンサーとして構成されている。 [First embodiment]
<Sensor unit>
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.
（圧電素子）
　圧電素子２は可撓性を有する。圧電素子２は、圧電膜１１が厚さ方向に入射する音波又は振動によって変形可能に構成されており、これにより音又は振動を検出可能に構成されている。圧電素子２は、音又は振動を検出するための検出領域Ｘを有する。詳細には、圧電素子２は、図２に示すように、平面視矩形状の検出領域Ｘと、検出領域Ｘの平面視における長手方向の両外側に形成され、一対の電極１２、１３及び一対のリード線１６ａ、１６ｂが接続される一対の接続領域（第１接続領域Ｙ１及び第２接続領域Ｙ２）とを有する。圧電素子２は、この接続領域Ｙ１、Ｙ２において第１リード線１６ａ及び第２リード線１６ｂを介してシールド部３ａ、３ｂと部分的に固定されている。つまり、当該センサーユニット１は、検出領域Ｘが一対のシールド部３ａ、３ｂと固定されていない。当該センサーユニット１は、検出領域Ｘが一対のシールド部３ａ、３ｂと固定されていないので、一対のシールド部３ａ、３ｂが検出領域Ｘの変形に及ぼす影響を容易かつ確実に取り除くことができ、その結果音又は振動の検出精度を著しく高めることができる。 (Piezoelectric element)
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. Specifically, as shown in FIG. 2, 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.
　圧電膜１１は、音波や振動によって変形可能に構成されている。圧電膜１１の具体的構成としては、音波や振動によって撓み変形するものや圧縮変形するもの等、公知の構成のものを採用可能である。圧電膜１１は、厚さ方向に荷重を付加した場合に正（プラス）に帯電する側が第１電極１２側に配置され、負（マイナス）に帯電する側が第２電極１３側に配置されている。圧電膜１１は、第１接続領域Ｙ１及び第２接続領域Ｙ２が長手方向両端部を構成する帯状に形成されている。圧電膜１１の平均厚さとしては、例えば３０μｍ以上１５０μｍ以下とすることができる。圧電膜１１の長手方向平均長さとしては、例えば２０ｍｍ以上１００ｍｍ以下とすることができる。圧電膜１１の短手方向の平均長さとしては、例えば１０ｍｍ以上８０ｍｍ以下とすることができる。 The piezoelectric film 11 is configured to be deformable by sound waves or vibration. As 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. When a load is applied in the thickness direction, 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 μm or more and 150 μm 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.
　第１電極１２及び第２電極１３は、圧電膜１１の厚さ方向両面の略全面に積層されている。第１電極１２及び第２電極１３は、金属等の導電性を有する材料を主成分として形成される。なお、「主成分」とは、最も含有量の多い成分をいい、例えば含有量が５０質量％以上の成分をいう。 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.
　第１電極１２はシグナル電極を構成し、第２電極１３はグランド電極を構成している。当該センサーユニット１は、圧電膜１１の変形により電荷を生じる。当該センサーユニット１は、第２電極１３を基準電位として第１電極１２の電位を測定することで音や振動を検出可能に構成されている。 The first electrode 12 constitutes a signal electrode, and 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.
（シールド部）
　一対のシールド部３ａ、３ｂは、それぞれ圧電素子２に部分的に固定される。詳細には一対のシールド部３ａ、３ｂは、圧電素子２の平面方向（厚さ方向と平行な方向）の移動を規制するよう第１リード線１６ａ及び第２リード線１６ｂを介して圧電素子２に部分的に固定される。圧電素子２の一対のシールド部３ａ、３ｂと固定されていない領域は、他の部材と接着されない非接着領域である。一対のシールド部３ａ、３ｂは可撓性を有する。一対のシールド部３ａ、３ｂは、シールド層１５及びこのシールド層１５の内面に直接積層される絶縁層１４ａ、１４ｂの２層構造体であり、絶縁層１４ａ、１４ｂの内面が圧電素子２に部分的に固定されている。一対のシールド部３ａ、３ｂと第１リード線１６ａ及び第２リード線１６ｂとは公知の接着剤等によって固定されている。 (Shield part)
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.
　圧電素子１１及び一対のシールド部３ａ、３ｂの固定部Ｒの平均幅の下限としては、１ｍｍが好ましく、２ｍｍがより好ましい。一方、固定部Ｒの平均幅の上限としては、５ｍｍが好ましく、３ｍｍがより好ましい。前記平均幅が前記下限より小さいと、固定部Ｒの接着強度が不十分となるおそれがある。逆に、前記平均幅が前記上限を超えると、固定部Ｒが不要に大きくなり、検出領域Ｘを十分に大きくし難くなるおそれがある。 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. On the other hand, 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.
　平面視における圧電素子２の面積に対する固定部Ｒの面積の比の上限としては、０．３が好ましく、０．２がより好ましく、０．１がさらに好ましい。前記比が前記上限を超えると、固定部Ｒが不要に大きくなり、固定部Ｒの圧電素子１１の変形に及ぼす影響が大きくなるおそれがある。一方、前記比の下限としては、一対のシールド部３ａ、３ｂ及び圧電素子１１の位置ずれを防止できる限り特に限定されるものではなく、例えば０．０１とすることができる。 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. On the other hand, 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.
　シールド部３ａ、３ｂは、平面視で検出領域Ｘの全領域を被覆するよう配設されている。このように、シールド部３ａ、３ｂが平面視で検出領域Ｘの全領域を被覆することで外部ノイズの影響を容易かつ確実に取り除くことができる。 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.
　絶縁層１４ａ、１４ｂは、シールド部３ａ、３ｂの最内層を構成する。絶縁層１４ａ、１４ｂは可撓性を有する。絶縁層１４ａ、１４ｂは合成樹脂を主成分として形成されている。前記合成樹脂としては、例えばポリエチレン、ポリプロピレン、ポリ塩化ビニル、ポリカーボネート、ポリエステル、ポリアミド、ポリアセタール、ポリイミド、アクリル樹脂等が挙げられる。中でも、電気的特性、機械的特性、コスト等の点からポリエチレンテレフタレートが好ましい。 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. Examples of the synthetic resin include polyethylene, polypropylene, polyvinyl chloride, polycarbonate, polyester, polyamide, polyacetal, polyimide, and acrylic resin. Among these, polyethylene terephthalate is preferable from the viewpoint of electrical characteristics, mechanical characteristics, cost, and the like.
　絶縁層１４ａ、１４ｂの平均厚さの下限としては、０．１μｍが好ましく、１μｍがより好ましい。一方、絶縁層１４ａ、１４ｂの平均厚さの上限としては、５００μｍが好ましく、１００μｍがより好ましい。絶縁層１４ａ、１４ｂの平均厚さが前記下限に満たないと、絶縁層１４ａ、１４ｂの強度が不十分となるおそれがある。逆に、絶縁層１４ａ、１４ｂの平均厚さが前記上限を超えると、シールド部３ａ、３ｂが不要に厚くなったり、シールド部３ａ、３ｂの可撓性が不十分となるおそれがある。 The lower limit of the average thickness of the insulating layers 14a and 14b is preferably 0.1 μm, and more preferably 1 μm. On the other hand, the upper limit of the average thickness of the insulating layers 14a and 14b is preferably 500 μm, and more preferably 100 μm. 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.
　シールド層１５は導電性を有する。シールド層１５は、シールド部３ａ、３ｂの最外層を構成する。一対のシールド部３ａ、３ｂを構成するシールド層１５は、１枚のフィルム部材から構成される。具体的には、シールド層１５は、帯状のフィルム部材によって形成されており、このフィルム部材の長手方向中央部を折り返した状態で、折り返し部Ｚによって区分される一方側の領域の内面に一方の絶縁層１４ａが積層され、他方側の領域の内面に他方の絶縁層１４ｂが積層されている。また、シールド層１５は、折り返し部Ｚの内面に第２リード線１６ｂが当接している。シールド層１５及び第２リード線１６ｂは、半田、導電性接着剤等によって接着されている。これにより、シールド層１５は、第２リード線１６ｂと電気的に接続されている。シールド層１５は、接地して用いられ、外部ノイズの影響を低減する。なお、本実施形態においては、一方の絶縁層１４ａ及び他方の絶縁層１４ｂは別部材として形成されているが、シールド層１５の内面に一対の絶縁層１４ａ、１４ｂを兼ねる１枚の絶縁層が積層されていてもよい。 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. Specifically, 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. In the present embodiment, 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.
　シールド層１５は金属を主成分として形成される。前記金属としては、例えば銀、銅、金、ニッケル、アルミニウム等が挙げられる。シールド層１５は、例えば前記金属を主成分とする金属箔によって形成される。また、一対のシールド部３ａ、３ｂは、例えばこの金属箔に一対の絶縁層１４ａ、１４ｂの形成材料を含む塗工液を塗布して乾燥することで、この金属箔に一対の絶縁層１４ａ、１４ｂを積層することで形成される。シールド層１５の平均厚さの下限としては、０．０１μｍが好ましく、０．１μｍがより好ましい。一方、シールド層１５の平均厚さの上限としては、５００μｍが好ましく、１００μｍがより好ましい。前記平均厚さが前記下限より小さいと、シールド層１５が意図せず断裂するおそれがある。逆に、前記平均厚さが前記上限を超えると、シールド部３ａ、３ｂが不要に厚くなったり、シールド部３ａ、３ｂの可撓性が不十分となるおそれがある。 The shield layer 15 is formed mainly of metal. Examples of 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. In addition, 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 μm, and more preferably 0.1 μm. On the other hand, the upper limit of the average thickness of the shield layer 15 is preferably 500 μm, and more preferably 100 μm. 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.
　圧電素子２と一対のシールド部３ａ、３ｂとは公知の接着剤等によって接着されていてもよいが、圧電素子２と一対のシールド部３ａ、３ｂとは接着されていないことが好ましい。当該センサーユニット１は、圧電素子２と一対のシールド部３ａ、３ｂとが接着されていないことによって、一対のシールド部３ａ、３ｂが圧電膜１１の変形に及ぼす影響をより抑えることができる。 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.
　圧電素子２と一対のシールド部３ａ、３ｂとが接着されていない場合において、圧電素子２と一対のシールド部３ａ、３ｂとは密着していてもよいが、圧電素子２と一対のシールド部３ａ、３ｂとの間に空間を有することが好ましい。当該センサーユニット１は、圧電素子２と一対のシールド部３ａ、３ｂとの間に空間を有することによって、一対のシールド部３ａ、３ｂが圧電膜１１の変形に及ぼす影響をさらに抑えることができる。 In the case where 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.
　検出領域Ｘの平面面積に対する検出領域Ｘの表面における圧電素子１１及び一対のシールド部３ａ、３ｂが密着していない空間面積の比の下限としては、０．５が好ましく、０．７がより好ましく、０．９がさらに好ましい。前記比が前記下限以上であることで、一対のシールド部３ａ、３ｂが圧電膜１１の変形に及ぼす影響をより的確に抑えやすい。一方、前記比の上限としては、特に限定されるものではなく、１．０とすることができる。 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. When 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. On the other hand, the upper limit of the ratio is not particularly limited and can be 1.0.
　一対のシールド部３ａ、３ｂは厚さ方向に貫通する複数の貫通孔（不図示）を有していてもよい。当該センサーユニット１は、圧電素子２と一対のシールド部３ａ、３ｂとの間に空間を有する場合、この空間に存在する空気の熱膨張によって一対のシールド部３ａ、３ｂが外側に膨れるおそれや、前記空気の冷却によって一対のシールド部３ａ、３ｂが圧電素子２と密着するおそれがある。特に、当該センサーユニット１は、一対のシールド部３ａ、３ｂと圧電素子２とが密着すると、音や振動の検出精度が低下するおそれがある。これに対し、当該センサーユニット１は、一対のシールド部３ａ、３ｂを厚さ方向に貫通する複数の貫通孔を有することによって、前記空気の熱膨張や冷却に起因する一対のシールド部３ａ、３ｂの膨れや圧電素子２との密着を抑制することでき、使用環境によらず音や振動の検出精度を高めることができる。 The pair of shield portions 3a and 3b may have a plurality of through holes (not shown) penetrating in the thickness direction. When the sensor unit 1 has a space between the piezoelectric element 2 and the pair of shield portions 3a and 3b, 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. In particular, in the sensor unit 1, when the pair of shield portions 3a and 3b and the piezoelectric element 2 are in close contact with each other, the detection accuracy of sound and vibration may be reduced. On the other hand, 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.
　一対のシールド部３ａ、３ｂが複数の貫通孔を有する場合、これらの貫通孔は平面視で検出領域Ｘと重ならない領域に形成されていることが好ましい。このように、複数の貫通孔が検出領域Ｘと重ならない領域に形成されていることで、これらの貫通孔に起因してシールド効果が低くなることを容易かつ確実に防止することができる。前記複数の貫通孔の平均径としては、例えば１００μｍ以上５ｍｍ以下とすることができる。前記平均径が前記下限に満たないと、一対のシールド部３ａ、３ｂの膨れや圧電素子２との密着を十分に抑制することができないおそれがある。逆に、前記平均径が前記上限を超えると、複数の貫通孔が圧電膜１１の変形に影響を及ぼすおそれがある。 When the pair of shield portions 3a and 3b have a plurality of through holes, these through holes are preferably formed in a region that does not overlap the detection region X in plan view. As described above, since the plurality of through holes are formed in the region that does not overlap with the detection region X, it is possible to easily and reliably prevent the shielding effect from being lowered due to the through holes. The average diameter of the plurality of through holes can be, for example, 100 μm 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.
（リード線）
　第１リード線１６ａ及び第２リード線１６ｂは、例えば導電性を有する線状の導体によって形成される。第１リード線１６ａは、検出回路と接続される側と反対側の端部が二股に分岐しており、この分岐部が第１接続領域Ｙ１及び第２接続領域Ｙ２で第１電極１２の外面に固定されている。これにより、第１リード線１６ａは、第１電極１２と電気的に接続されている。また、第２リード線１６ｂは、検出回路と接続される側と反対側の端部が二股に分岐しており、この分岐部が第１接続領域Ｙ１及び第２接続領域Ｙ２で第２電極１３の外面に固定されている。これにより、第２リード線１６ｂは、第２電極１３と電気的に接続されている。 (Lead)
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. In addition, 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.
＜利点＞
　当該センサーユニット１は、一対のシールド部３ａ、３ｂが圧電素子２に部分的に固定されており、一対のシールド部３ａ、３ｂが圧電素子２に全面的に固定されていないので、一対のシールド部３ａ、３ｂが圧電素子の共振に及ぼす影響を低減することができる。そのため、当該センサーユニット１は検出精度に優れる。当該センサーユニット１は、音や振動を高精度で検出するのに優れており、特に音の検出精度を効果的に高めることができる。 <Advantages>
In the sensor unit 1, 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.
［第二実施形態］
＜センサーユニット＞
　図３のセンサーユニット２１は、シート状の圧電素子２５と、圧電素子２５の厚さ方向両側に配設される一対のシート状のシールド部３ａ、３ｂとを備える。圧電素子２５は一対のシールド部３ａ、３ｂと部分的に固定されている。圧電素子２５は、圧電膜２６と、圧電膜２６の一方側の面に積層される第１電極２７と、圧電膜２６の他方側の面に積層される第２電極２８とを有する。一対のシールド部３ａ、３ｂは、絶縁層１４ａ、１４ｂと、絶縁層１４ａ、１４ｂの外面側に積層されるシールド層１５とを有する。また、当該センサーユニット２１は、第１電極２７に接続され、外部に電気信号を出力する第１リード線２９ａと、第２電極２８に接続され、外部に電気信号を出力する第２リード線２９ｂとを有する。さらに、当該センサーユニット２１は、圧電素子２５の平面視両側に、一対のシールド部３ａ、３ｂを離間した状態で保持するスペーサ２２ａ、２２ｂを有する。当該センサーユニット２１は、例えば音響機器等に取り付けられて用いられ、音や振動を検出する歪みセンサーとして構成されている。当該センサーユニット２１における一対のシールド部３ａ、３ｂについては、図１のセンサーユニット１と同様のため、同一符号を付して説明を省略する。 [Second Embodiment]
<Sensor unit>
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. Furthermore, 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.
（圧電素子）
　圧電素子２５は可撓性を有する。圧電素子２５は、圧電膜２６が厚さ方向に入射する音波又は振動によって変形可能に構成されており、これにより音又は振動を検出可能に構成されている。圧電素子２５は、音又は振動を検出するための検出領域Ｘを有する。詳細には、圧電素子２５は、図４に示すように、平面視矩形状の検出領域Ｘと、検出領域Ｘから平面視外側に突出し、第１リード線２９ａと接続される第１接続領域Ｙ１と、検出領域Ｘから平面視外側に突出し、第２リード線２９ｂと接続される第２接続領域Ｙ２とを有する。第１接続領域Ｙ１及び第２接続領域Ｙ２は反対方向に突出している。圧電素子２５は、形状が相違する以外は図１の圧電素子２と同様に構成することができる。 (Piezoelectric element)
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. Specifically, as shown in FIG. 4, 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.
（リード線）
　第１リード線２９ａ及び第２リード線２９ｂは、例えば導電性を有する線状の導体によって形成される。第１リード線２９ａは、第１接続領域Ｙ１において第１電極２７の外面に積層され、これにより第１電極２７と電気的に接続されている。また、第２リード線２９ｂは、第２接続領域Ｙ２において第２電極２８の外面に積層され、これにより第２電極２８と電気的に接続されている。 (Lead)
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.
（スペーサ）
　スペーサ２２ａ、２２ｂは、平面視で圧電素子２５を囲むように配設されている。スペーサ２２ａ、２２ｂは、それぞれ一対のシールド部３ａ、３ｂの内面と平行に配設される一対の支持面を有する。スペーサ２２ａ、２２ｂは、図４に示すように、平面視で第１リード線２９ａ及び第２リード線２９ｂと重なり合わない領域で、支持面を一対のシールド部３ａ、３ｂの内面に全面的に当接した状態で配設されている。これにより、スペーサ２２ａ、２２ｂは、少なくとも圧電素子２５の平面視両側において一対のシールド部３ａ、３ｂを離間した状態で保持しており、特に本実施形態では圧電素子２５の周囲の略全領域において一対のシールド部３ａ、３ｂを離間した状態で保持している。 (Spacer)
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. As shown in FIG. 4, 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 | positions in the state contact | abutted. Thereby, 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. In particular, in this embodiment, in the substantially entire region around the piezoelectric element 25. The pair of shield portions 3a and 3b are held in a separated state.
　スペーサ２２ａ、２２ｂの高さは、圧電素子２５の最大厚さ以上であることが好ましく、圧電素子２５及び一対のリード線２９ａ、２９ｂの合計厚さと等しいことがより好ましい。スペーサ２２ａ、２２ｂの高さが圧電素子２５及び一対のリード線２９ａ、２９ｂの合計厚さと等しいことによって、圧電素子２５を一対のシールド部３ａ、３ｂと部分的に固定しつつ、スペーサ２２ａ、２２ｂの支持面を一対のシールド部３ａ、３ｂの内面に当接した状態で保持しやすい。なお、「スペーサの高さが圧電素子及び一対のリード線の合計厚さと等しい」とは、スペーサの高さと圧電素子及び一対のリード線の合計厚さとの差の絶対値が５００μｍ以下であることをいい、好ましくは１００μｍ以下であることをいい、より好ましくは５０μｍ以下であることをいう。 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 height of the spacer is equal to the total thickness of the piezoelectric element and the pair of lead wires” means that the absolute value of the difference between the height of the spacer and the total thickness of the piezoelectric element and the pair of lead wires is 500 μm or less. Preferably 100 μm or less, more preferably 50 μm or less.
　スペーサ２２ａ、２２ｂの材質としては、特に限定されるものではないが、一対のシールド部３ａ、３ｂの間のスペースを確保する樹脂製の絶縁体のものであるとよい。スペーサ２２ａ、２２ｂは、一対のシールド部３ａ、３ｂの固定に寄与するよう粘着性を有していてもよい。また、スペーサ２２ａ、２２ｂは、導電性を有する金属からなるものでもよい。スペーサ２２ａ、２２ｂが導電性を有する場合、シールド効果を高めることができる。特に当該センサーユニット２１は、スペーサ２２ａ、２２ｂが平面視で圧電素子２５を囲むように配設されているので、スペーサ２２ａ、２２ｂによって圧電素子２５の平面方向外側領域を封止することができ、これにより外部ノイズが圧電素子２５側に侵入することをより確実に防止することができる。 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. In particular, 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.
　一対のシールド部３ａ、３ｂは、図４に示すように、接続領域Ｙ１、Ｙ２において一対のリード線２９ａ、２９ｂを介して圧電素子２５に部分的に固定されている。また、平面視で第１リード線２９ａ及び第２リード線２９ｂと重なり合わない領域において、一対のシールド部３ａ、３ｂの内面は、圧電素子２５の周囲を囲むようにスペーサ２２ａ、２２ｂによって支持されている。これにより、圧電素子２５の検出領域Ｘは一対のシールド部３ａ、３ｂと固定されていない。またこれにより、圧電素子２５と一対のシールド部３ａ、３ｂとの間には空間を有する。詳細には検出領域Ｘの表面の全領域と一対のシールド部３ａ、３ｂの内面との間に空気層が形成されている。換言すると、当該センサーユニット２１は、検出領域Ｘの平面面積に対する検出領域Ｘの表面における圧電素子２５及び一対のシールド部３ａ、３ｂが密着していない空間面積の比が１である。これにより、当該センサーユニット２１は、一対のシールド部３ａ、３ｂが検出領域Ｘの変形に及ぼす影響を的確に取り除くことができる。 As shown in FIG. 4, 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. Specifically, 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. In other words, in the sensor unit 21, 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. Thereby, 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.
　圧電素子２５及び一対のシールド部３ａ、３ｂは、接続領域Ｙ１、Ｙ２において点状に固定されている。圧電素子２５及び一対のシールド部３ａ、３ｂの固定部Ｒの平均径の下限としては、１ｍｍが好ましく、２ｍｍがより好ましい。一方、固定部Ｒの平均径の上限としては、５ｍｍが好ましく、３ｍｍがより好ましい。前記平均径が前記下限より小さいと、固定部Ｒの接着強度が不十分となるおそれがある。逆に、前記平均径が前記上限を超えると、固定部Ｒの圧電素子２５の変形に及ぼす影響が大きくなるおそれがある。なお、「平均径」とは、等面積の真円に換算した径をいう。また、「固定部の平均径」とは、固定部の平面視における平均径をいう。 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. On the other hand, 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.
＜利点＞
　当該センサーユニット２１は、圧電素子２５の平面視両側に、一対のシールド部３ａ、３ｂを離間した状態で保持するスペーサ２２ａ、２２ｂを有するので、一対のシールド部３ａ、３ｂが圧電素子２５、特に圧電素子２５の検出領域Ｘの変形に及ぼす影響の低減効果を高めやすい。 <Advantages>
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.
［第三実施形態］
＜センサーユニット＞
　図５のセンサーユニット３１は、シート状の圧電素子２５と、圧電素子２５の厚さ方向両側に配設される一対のシート状のシールド部３３ａ、３３ｂとを備える。圧電素子２５は一対のシールド部３３ａ、３３ｂと部分的に固定されている。圧電素子２５は、圧電膜２６と、圧電膜２６の一方側の面に積層される第１電極２７と、圧電膜２６の他方側の面に積層される第２電極２８とを有する。第１電極２７はシグナル電極を構成し、第２電極２８はグランド電極を構成する。つまり、圧電素子２５は、厚さ方向一方側に積層されるシグナル電極と、厚さ方向他方側に配設されるグランド電極とを有する。一方のシールド部３３ａ（圧電素子２５の第１電極２７側に配設されるシールド部）は、絶縁層１４ａと、絶縁層１４ａの外面側に積層されるシールド層１５と、絶縁層１４ａの内面側に積層される導電層３４とを有する。他方のシールド部３３ｂ（圧電素子２５の第２電極２８側に配設されるシールド部）は、絶縁層１４ｂと、絶縁層１４ｂの外面側に積層されるシールド層１５とを有する。また、当該センサーユニット３１は、第１電極２７に接続され、外部に電気信号を出力する第１リード線２９ａと、第２電極２８に接続され、外部に電気信号を出力する第２リード線２９ｂとを有する。さらに、当該センサーユニット３１は、圧電素子２５の平面視両側に、一対のシールド部３３ａ、３３ｂを離間した状態で保持するスペーサ２２ａ、２２ｂを有する。当該センサーユニット３１は、例えば音響機器等に取り付けられて用いられ、音や振動を検出する歪みセンサーとして構成されている。当該センサーユニット３１は、前記シグナル電極側に配設される一方のシールド部３３ａが、絶縁層１４ａの内面側に積層される導電層３４を有する以外、図３のセンサーユニット２１と同様の構成を有する。そのため、以下では一方のシールド部３３ａについてのみ説明する。 [Third embodiment]
<Sensor unit>
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, and the second electrode 28 constitutes a ground electrode. That is, 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. Furthermore, 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.
（シールド部）
　前述のように、一方のシールド部３３ａは、絶縁層１４ａと、絶縁層１４ａの外面側に積層されるシールド層１５と、絶縁層１４ａの内面側に積層される導電層３４とを有する。一方のシールド部３３ａは、絶縁層１４ａ、シールド層１５及び導電層３４の３層構造体である。一方のシールド部３３ａは可撓性を有する。シールド部３３ａの絶縁層１４ａ及びシールド層１５の具体的構成としては、図１のセンサーユニット１と同様とすることができる。 (Shield part)
As described above, 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.
（導電層）
　導電層３４は、一方のシールド部３３ａの最内層を構成する。導電層３４は導電性を有する。また、導体層３４は、シールド層１５と絶縁状態で保持されている。導電層３４は、第１電極２７（シグナル電極）と電気的に接続されている。導電層３４は、検出領域Ｘの表面側の全領域を被覆するよう配設されることが好ましく、圧電膜２６の表面側の全領域を被覆するよう配設されることがより好ましい。導電層３４と検出領域Ｘとの間には空気層が形成されていることが好ましい。また、この空気層は、検出領域Ｘの表面の全面に亘って形成されていることがより好ましい。 (Conductive layer)
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.
　導電層３４は、例えば金属又は金属化合物を主成分として形成される。前記金属としては、例えば銀、銅、金、ニッケル、アルミニウム、カーボン等が挙げられる。また、前記金属化合物としては、例えばＩＴＯ等が挙げられる。導電層３４は、金属印刷又は金属蒸着によって絶縁層１４ａの内面に積層されてもよく、絶縁層１４ａの内面に金属箔を接着することで積層されてもよい。導電層３４の平均厚さの下限としては、０．０１μｍが好ましく、０．１μｍがより好ましい。一方、導電層３４の平均厚さの上限としては、５００μｍが好ましく、１００μｍがより好ましい。前記平均厚さが前記下限より小さいと、導電層３４の強度が不十分となるおそれがある。逆に、前記平均厚さが前記上限を超えると、シールド部３３ａが不要に厚くなったり、シールド部３３ａの可撓性が不十分となるおそれがある。なお、当該センサーユニット３１は、導電層３４と第１リード線２９ａとが、半田、導電性接着剤等によって接着されることで導電層３４及び第１電極２７が電気的に接続されてもよく、第１リード線２９ａが導電層３４の端部から連続して導電層３４と一体的に形成されることで導電層３４及び第１電極２７が電気的に接続されてもよい。 The conductive layer 34 is formed using, for example, a metal or a metal compound as a main component. Examples of the metal include silver, copper, gold, nickel, aluminum, and carbon. Examples of 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 μm, and more preferably 0.1 μm. On the other hand, the upper limit of the average thickness of the conductive layer 34 is preferably 500 μm, and more preferably 100 μm. If the average thickness is smaller than the lower limit, the strength of the conductive layer 34 may be insufficient. Conversely, if the average thickness exceeds the upper limit, the shield portion 33a may become unnecessarily thick or the flexibility of the shield portion 33a may be insufficient. In the sensor unit 31, 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.
＜利点＞
　当該センサーユニット３１は、第１電極２７側に配設されるシールド部３３ａが、絶縁層１４ａ及び絶縁層１４ａの内面側に積層され、第１電極２７と電気的に接続される導電層３４を有するので、導電層３４及び第１電極２７を同電位に保つことができ、これにより第１電極２７及び導電層３４間における静電容量の発生を抑制することができる。従って、当該センサーユニット３１は、この静電容量が音や振動の検出に与える影響を抑制することができ、音や振動の検出精度をより高めることができる。 <Advantages>
In the sensor unit 31, 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.
［その他の実施形態］
　前記実施形態は、本発明の構成を限定するものではない。従って、前記実施形態は、本明細書の記載及び技術常識に基づいて前記実施形態各部の構成要素の省略、置換又は追加が可能であり、それらは全て本発明の範囲に属するものと解釈されるべきである。 [Other Embodiments]
The said embodiment does not limit the structure of this invention. Therefore, in the above-described embodiment, components of each part of the above-described embodiment can be omitted, replaced, or added based on the description and common general knowledge of the present specification, and they are all interpreted as belonging to the scope of the present invention. Should.
　例えば、前記スペーサは圧電素子の平面視両側のみに配設されていてもよい。 For example, the spacer may be provided only on both sides of the piezoelectric element in plan view.
　前記圧電素子は必ずしもリード線を介して一対のシールド部に固定される必要はなく、例えば電極の外面（つまり前記検出領域の外面）がシールド部に直接固定されてもよい。また、前記圧電素子がリード線を介して一対のシールド部に固定される場合であっても、具体的な固定方法は前述の実施形態の構成に限定されるものではない。例えば、図６に示すように、当該センサーユニット４１は、第２電極４２の外側に配設されるシールド部４３ｂが導電性を有するシールド層４５と、シールド層４５の内面に積層される絶縁層４４ｂと、導電性を有し、絶縁層４４ｂを厚さ方向に貫通する導電部４４ｃとを有し、第２リード線４６ｂがこの導電部４４ｃを介してシールド層４５と電気的に接続されてもよい。 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. For example, as shown in FIG. 6, 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.
　前記圧電素子の平面形状は、特に限定されるものではなく、用途に応じて適宜設計可能である。また、前述の各実施形態の構成は適宜組み合わせることが可能であり、例えば図３及び図５のセンサーユニット２１、３１においてスペーサ２２ａ、２２ｂを有しない構成を採用することも可能であり、図１及び図６のセンサーユニット１、４１においてスペーサを用いることも可能である。 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. For example, 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.
　前述の実施形態では、シールド層が帯状のフィルム部材の長手方向中央部を折り返すことで形成される構成について説明した。この点に関し、例えば図７に示すように、シールド層５５は、圧電素子の両面側に配設される一対の帯状のフィルム部材５５ａと、この一対のフィルム部材５５ａの長手方向一方側端部同士を接続する導電部材５５ｂとによって形成されてもよい。また、一対のフィルム部材５５ａ及び導電部材５５ｂの接続方法は特に限定されるものではなく、例えば導電性テープを用いて接続してもよく、ネジを用いて接続してもよい。 In the above-described embodiment, the configuration in which the shield layer is formed by folding the central portion in the longitudinal direction of the strip-shaped film member has been described. In this regard, for example, as shown in FIG. 7, 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. Moreover, 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.
　当該センサーユニットは、前述のように圧電素子及び一対のシールド部が部分的に固定されることで、一対のシールド部が圧電素子の共振に及ぼす影響を低減することができる。一方、当該センサーユニットは、必要に応じてシールド部の外面に錘を積層してもよい。具体的には、当該センサーユニットは、第１電極側に配設されるシールド部の外面に合成樹脂を主成分とするシート状の錘を積層してもよい。当該センサーユニットは、例えば第２電極側に配設されるシールド部の外面を弦楽器の響板に取り付けて用いる場合、第１電極側に配設されるシールド部の外面に錘を積層することで、圧電素子及び響板の間に空気層が形成されることを防止することができ、これにより響板の振動を圧電素子に伝わりやすくすることができる。また、当該センサーユニットは、圧電素子の第２電極の外面とこの第２電極側に配設されるシールド部の内面とのみを密着させることも可能であり、かかる構成によっても響板の振動を圧電素子に伝わりやすくすることが可能である。 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. On the other hand, the sensor unit may be stacked with a weight on the outer surface of the shield part as necessary. Specifically, in the sensor unit, 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. For example, when the sensor unit is used by attaching the outer surface of the shield part disposed on the second electrode side to the sound board of the stringed instrument, the sensor unit is configured by stacking a weight on the outer surface of the shield part disposed on the first electrode side. In addition, it is possible to prevent an air layer from being formed between the piezoelectric element and the soundboard, thereby making it easier to transmit the vibration of the soundboard to the piezoelectric element. In addition, 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.
　当該センサーユニットは、例えば弦楽器の響板等に取り付けられる楽器用ピックアップとして用いることができる他、バウンダリーマイクロホンや、建築物、機械、輸送機等の異音や騒音を検出するための装置等、楽器以外の部材に用いることも可能である。 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.
　以上説明したように、本発明のセンサーユニットは、音や振動の検出精度に優れるので、弦楽器等の楽器用ピックアップとして用いられるのに適している。 As described above, 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.
１、２１、３１、４１　センサーユニット
２、２５　圧電素子
３ａ、３ｂ、３３ａ、３３ｂ、４３ｂ　シールド部
１１、２６　圧電膜
１２、２７　第１電極
１３、２８、４２　第２電極
１４ａ、１４ｂ、４４ｂ　絶縁層
１５、４５、５５　シールド層
１６ａ、２９ａ　第１リード線
１６ｂ、２９ｂ、４６ｂ　第２リード線
２２ａ、２２ｂ　スペーサ
３４　導電層
４４ｃ　導電部
５５ａ　フィルム部材
５５ｂ　導電部材
Ｒ　固定部
Ｘ　検出領域
Ｙ１　第１接続領域
Ｙ２　第２接続領域
Ｚ　折り返し部 1, 21, 31, 41 Sensor unit 2, 25 Piezoelectric element 3a, 3b, 33a, 33b, 43b Shield part 11, 26 Piezoelectric film 12, 27 First electrode 13, 28, 42 Second electrode 14a, 14b, 44b Insulation Layers 15, 45, 55 Shield layers 16a, 29a First lead wires 16b, 29b, 46b Second lead wires 22a, 22b Spacer 34 Conductive layer 44c Conductive portion 55a Film member 55b Conductive member R Fixed portion X Detection region Y1 First connection Area Y2 Second connection area Z Folded part

Claims (5)

  1. 　シート状の圧電素子と、
    　前記圧電素子の厚さ方向両側に配設され、この圧電素子に部分的に固定される一対のシート状のシールド部と
    　を備えるセンサーユニット。     A sheet-like piezoelectric element;
    A sensor unit comprising: a pair of sheet-like shield portions disposed on both sides in the thickness direction of the piezoelectric element and partially fixed to the piezoelectric element.
  2. 　前記圧電素子の平面視両側に、前記一対のシールド部を離間した状態で保持するスペーサを有する請求項１に記載のセンサーユニット。 The sensor unit according to claim 1, further comprising spacers that hold the pair of shield portions in a separated state on both sides of the piezoelectric element in plan view.
  3. 　前記圧電素子と一対のシールド部との間に空間を有する請求項１又は請求項２に記載のセンサーユニット。 The sensor unit according to claim 1 or 2, wherein a space is provided between the piezoelectric element and the pair of shield portions.
  4. 　前記圧電素子が厚さ方向一方側に積層されるシグナル電極を備え、このシグナル電極側に配設される前記シールド部が、絶縁層、及びこの絶縁層の内面側に積層され、前記シグナル電極と電気的に接続される導電層を有する請求項１、請求項２又は請求項３に記載のセンサーユニット。 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, and the signal electrode The sensor unit according to claim 1, further comprising a conductive layer electrically connected.
  5. 　前記圧電素子の検出領域が前記一対のシールド部と固定されていない請求項１から請求項４のいずれか１項に記載のセンサーユニット。 The sensor unit according to any one of claims 1 to 4, wherein a detection area of the piezoelectric element is not fixed to the pair of shield portions.
PCT/JP2017/047381 2017-03-13 2017-12-28 Sensor unit WO2018168168A1 (en)

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