WO2021187086A1 - 積層圧電素子および電気音響変換器 - Google Patents

積層圧電素子および電気音響変換器 Download PDF

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Publication number
WO2021187086A1
WO2021187086A1 PCT/JP2021/007901 JP2021007901W WO2021187086A1 WO 2021187086 A1 WO2021187086 A1 WO 2021187086A1 JP 2021007901 W JP2021007901 W JP 2021007901W WO 2021187086 A1 WO2021187086 A1 WO 2021187086A1
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Prior art keywords
piezoelectric
layer
laminated
piezoelectric film
protruding portion
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PCT/JP2021/007901
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English (en)
French (fr)
Japanese (ja)
Inventor
輝男 芦川
平口　和男
裕介 香川
三好　哲
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Fujifilm Corp
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Fujifilm Corp
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Priority to JP2022508187A priority Critical patent/JP7457790B2/ja
Priority to CN202180019823.7A priority patent/CN115244720A/zh
Priority to KR1020227031142A priority patent/KR20220140576A/ko
Priority to EP21771776.8A priority patent/EP4124066A4/en
Publication of WO2021187086A1 publication Critical patent/WO2021187086A1/ja
Priority to US17/946,825 priority patent/US12075211B2/en
Anticipated expiration legal-status Critical
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    • 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
    • H10N30/80—Constructional details
    • H10N30/87—Electrodes or interconnections, e.g. leads or terminals
    • 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
    • H10N30/50—Piezoelectric or electrostrictive devices having a stacked or multilayer structure
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R17/00—Piezoelectric transducers; Electrostrictive transducers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R7/00—Diaphragms for electromechanical transducers; Cones
    • H04R7/02—Diaphragms for electromechanical transducers; Cones characterised by the construction
    • H04R7/04—Plane diaphragms
    • 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
    • H10N30/20—Piezoelectric or electrostrictive devices with electrical input and mechanical output, e.g. functioning as actuators or vibrators
    • 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
    • H10N30/80—Constructional details
    • H10N30/87—Electrodes or interconnections, e.g. leads or terminals
    • H10N30/872—Interconnections, e.g. connection electrodes of multilayer piezoelectric or electrostrictive devices
    • 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
    • H10N30/80—Constructional details
    • H10N30/87—Electrodes or interconnections, e.g. leads or terminals
    • H10N30/875—Further connection or lead arrangements, e.g. flexible wiring boards, terminal pins
    • 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
    • H10N30/80—Constructional details
    • H10N30/88—Mounts; Supports; Enclosures; Casings
    • 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
    • H10N30/80—Constructional details
    • H10N30/88—Mounts; Supports; Enclosures; Casings
    • H10N30/883—Additional insulation means preventing electrical, physical or chemical damage, e.g. protective coatings
    • 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
    • H10N30/01—Manufacture or treatment
    • H10N30/05—Manufacture of multilayered piezoelectric or electrostrictive devices, or parts thereof, e.g. by stacking piezoelectric bodies and electrodes
    • H10N30/057—Manufacture of multilayered piezoelectric or electrostrictive devices, or parts thereof, e.g. by stacking piezoelectric bodies and electrodes by stacking bulk piezoelectric or electrostrictive bodies and electrodes
    • 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
    • H10N30/80—Constructional details
    • H10N30/85—Piezoelectric or electrostrictive active materials
    • H10N30/852—Composite materials, e.g. having 1-3 or 2-2 type connectivity

Definitions

  • the present invention relates to a laminated piezoelectric element and an electroacoustic transducer.
  • Piezoelectric elements are used for various purposes as so-called exciters that vibrate articles and make sounds when they are attached in contact with various articles. For example, by attaching an exciter to an image display panel, a screen, or the like and vibrating them, sound can be produced instead of a speaker.
  • the exciter when attaching an exciter to a flexible image display device, a retractable screen, etc., the exciter itself must be flexible (rollable) at least when not in use.
  • Patent Document 1 describes a polymer composite piezoelectric body in which piezoelectric particles are dispersed in a viscoelastic matrix made of a polymer material having viscoelasticity at room temperature, and is formed on one surface of the polymer composite piezoelectric body.
  • the upper thin film electrode having an area of less than or equal to the polymer composite piezoelectric material, the upper protective layer formed on the surface of the upper thin film electrode and having an area of more than or equal to the upper thin film electrode, and the opposite surface of the upper thin film electrode of the polymer composite piezoelectric body.
  • a piezoelectric laminate having a lower thin film electrode having an area of less than or equal to the polymer composite piezoelectric body, and a piezoelectric laminate having an area of more than or equal to the lower thin film electrode formed on the surface of the lower thin film electrode, and an upper portion.
  • a metal foil for drawing out the upper electrode, which is laminated on a part of the thin film electrode and at least a part is located outside the plane direction of the polymer composite piezoelectric material, and a part of the lower thin film electrode, which is laminated on a part, and at least a part is high.
  • an electroacoustic conversion film having a metal foil for drawing out a lower electrode located outside the plane direction of the molecular composite piezoelectric body.
  • the output of the laminated piezoelectric element depends on the direction of polarization of the piezoelectric layer of the piezoelectric film and the direction of the polarity of the electrode. It was found that the piezo may decrease or the piezo may not be deformed as a whole.
  • the electrode layer is formed very thin.
  • the electrode layer is provided in a state of being formed on a protective layer serving as a support. Therefore, the outermost layers on both main surfaces of the piezoelectric film serve as protective layers, and it is difficult to secure electrical contacts to the electrode layers.
  • An object of the present invention is to solve such a problem of the prior art, and to provide a laminated piezoelectric element capable of obtaining high piezoelectric characteristics and easily securing an electric contact to an electrode layer. There is.
  • the present invention has the following configuration.
  • a plurality of layers of piezoelectric films formed by laminating the first protective layer, the first electrode layer, the piezoelectric layer, the second electrode layer, and the second protective layer in this order are laminated.
  • Each piezoelectric layer is polarized in the thickness direction.
  • the first electrode is arranged on the upstream side in the polarization direction of the piezoelectric layer, and the second electrode is arranged on the downstream side.
  • the plurality of piezoelectric films have an adhesive portion to be adhered to the adjacent piezoelectric film, and at least the first electrode layer and the first protective layer, or the second electrode layer and the second electrode layer and the second electrode layer and the second electrode layer from the adhesive portion toward the outside in the plane direction. It has an adjacent piezoelectric film and a non-adhesive protrusion where the protective layer protrudes.
  • the protruding portion of each piezoelectric film has a first contact in which the first electrode layer of each piezoelectric film is electrically connected to each other, and a second contact in which the second electrode layer of each piezoelectric film is electrically connected to each other.
  • a laminated piezoelectric element in which at least one of the above is formed.
  • An electroacoustic converter comprising the laminated piezoelectric element according to any one of [1] to [13] and a diaphragm to which the laminated piezoelectric element is fixed.
  • the diaphragm has a quadrangular shape in which at least one set of two opposing sides is fixed, and when the distance between the fixed ends on the two facing sides is L, the laminated piezoelectric element is attached to the diaphragm.
  • FIG. 1 It is a figure which conceptually shows an example of the laminated piezoelectric element of this invention. It is a figure which conceptually shows an example of the piezoelectric film which comprises the laminated piezoelectric element shown in FIG. It is a conceptual diagram for demonstrating an example of the manufacturing method of a piezoelectric film. It is a conceptual diagram for demonstrating an example of the manufacturing method of a piezoelectric film. It is a conceptual diagram for demonstrating an example of the manufacturing method of a piezoelectric film. It is a conceptual diagram for demonstrating an example of the manufacturing method of a piezoelectric film. It is a conceptual diagram for demonstrating an example of the manufacturing method of a piezoelectric film. It is a conceptual diagram for demonstrating an example of the manufacturing method of a piezoelectric film.
  • FIG. 22 is a cross-sectional view taken along the line BB of FIG. It is a figure which conceptually shows another example of the laminated piezoelectric element of this invention. It is a partially enlarged view of FIG. 24. It is a partially enlarged view of FIG. 24.
  • FIG. 37 is a top view of FIG. 37. It is a side view of FIG. 37. It is a figure which shows the piezoelectric film which the laminated piezoelectric element of FIG. 37 has. It is a figure which shows the example which attached the conductive film to the laminated piezoelectric element of FIG. It is a figure which conceptually shows another example of the laminated piezoelectric element of this invention.
  • FIG. 43 It is a figure which conceptually shows another example of the laminated piezoelectric element of this invention. It is a side view of FIG. 43. It is a figure which conceptually shows another example of the electro-acoustic converter of this invention. It is a figure which conceptually shows another example of the electro-acoustic converter of this invention. It is a figure which conceptually shows another example of the electro-acoustic converter of this invention. It is a figure which conceptually shows another example of the electro-acoustic converter of this invention. It is a simulation result of the vibration of the diaphragm by the electroacoustic transducer shown in FIG. 45. It is a conceptual diagram for demonstrating FIG. 49.
  • FIG. 5 is an enlarged perspective view showing a part of the laminated piezoelectric element shown in FIG. 54. It is a figure which conceptually shows another example of the laminated piezoelectric element of this invention.
  • FIG. 5 is an enlarged perspective view showing a part of the laminated piezoelectric element shown in FIG. 56.
  • the description of the constituent elements described below may be based on a typical embodiment of the present invention, but the present invention is not limited to such an embodiment.
  • the numerical range represented by using "-" means a range including the numerical values before and after "-" as the lower limit value and the upper limit value.
  • the laminated piezoelectric material of the present invention A plurality of layers of piezoelectric films formed by laminating a first protective layer, a first electrode layer, a piezoelectric layer, a second electrode layer, and a second protective layer in this order are laminated. Each piezoelectric layer is polarized in the thickness direction. In each piezoelectric film, the first electrode is arranged on the upstream side in the polarization direction of the piezoelectric layer, and the second electrode is arranged on the downstream side.
  • Each of the plurality of piezoelectric films has an adhesive portion to be adhered to the adjacent piezoelectric film, and at least the first electrode layer and the first protective layer, or the second electrode layer from the adhesive portion toward the outside in the plane direction.
  • each piezoelectric film has a protruding portion that is not adhered to an adjacent piezoelectric film on which the second protective layer protrudes.
  • the protruding portion of each piezoelectric film has a first contact in which the first electrode layer of each piezoelectric film is electrically connected to each other, and a second contact in which the second electrode layer of each piezoelectric film is electrically connected to each other. It is a laminated piezoelectric element in which at least one of the above is formed.
  • FIG. 1 conceptually shows an example of the laminated piezoelectric element of the present invention.
  • the laminated piezoelectric element 10 shown in FIG. 1 has a configuration in which three piezoelectric films 12a, 12b, and 12c are laminated, and adjacent piezoelectric films are attached by an adhesive layer (adhesion layer) 14. Each piezoelectric film is connected to a power source that applies a driving voltage that expands and contracts the piezoelectric film.
  • the laminated piezoelectric element 10 shown in FIG. 1 is formed by laminating three layers of piezoelectric films, but the present invention is not limited to this.
  • the number of laminated piezoelectric films may be two layers or four or more layers. The same applies to the laminated piezoelectric element described later in this respect.
  • FIG. 2 conceptually shows the piezoelectric film 12 by a cross-sectional view.
  • the piezoelectric films 12a, 12b and 12c have the same configuration except that the stacking order and the vertical direction are different. Therefore, in the following description, when it is not necessary to distinguish the piezoelectric films, the piezoelectric films are not distinguished. Collectively, it is also referred to as a piezoelectric film 12.
  • the piezoelectric film 12 includes a piezoelectric layer 20 which is a sheet-like material having piezoelectricity, a first electrode layer 24 laminated on one surface of the piezoelectric layer 20, and a first electrode layer. It has a first protective layer 28 laminated on 24, a second electrode layer 26 laminated on the other surface of the piezoelectric layer 20, and a second protective layer 30 laminated on the second electrode layer 26. .. That is, the piezoelectric film 12 has a structure in which the first protective layer 28, the first electrode layer 24, the piezoelectric layer 20, the second electrode layer 26, and the second protective layer 30 are laminated in this order.
  • the piezoelectric film 12 (piezoelectric layer 20) is polarized in the thickness direction.
  • the electrode layer and the protective layer on the upstream side in the polarization direction of the piezoelectric film 12 are the first electrode layer 24 and the first protective layer 28, and the electrode layer and the protective layer on the downstream side are the second electrode layer 26 and the second protective layer 30. do.
  • the piezoelectric layer 20 preferably disperses the piezoelectric particles 36 in a viscoelastic matrix 34 made of a polymer material having viscoelasticity at room temperature, as conceptually shown in FIG. It is made of a polymer composite piezoelectric body.
  • room temperature refers to a temperature range of about 0 to 50 ° C.
  • the polymer composite piezoelectric body (piezoelectric layer 20) preferably has the following requirements.
  • (I) Flexibility For example, when gripping in a state of being loosely bent like a document like a newspaper or a magazine for carrying, it is constantly subjected to a relatively slow and large bending deformation of several Hz or less from the outside. become. At this time, if the polymer composite piezoelectric body is hard, a correspondingly large bending stress is generated, cracks are generated at the interface between the polymer matrix and the piezoelectric particle, and there is a possibility that it will eventually lead to fracture. Therefore, the polymer composite piezoelectric body is required to have appropriate softness. Further, if the strain energy can be diffused to the outside as heat, the stress can be relaxed. Therefore, it is required that the loss tangent of the polymer composite piezoelectric body is appropriately large.
  • the flexible polymer composite piezoelectric material used as an exciter is required to behave hard against vibrations of 20 Hz to 20 kHz and soft against vibrations of several Hz or less. Further, the loss tangent of the polymer composite piezoelectric body is required to be appropriately large for vibrations of all frequencies of 20 kHz or less. Further, it is preferable that the spring constant can be easily adjusted by laminating according to the rigidity (hardness, stiffness, spring constant) of the mating material (diaphragm) to be attached, and at that time, the adhesive layer 14 is thinned. The thinner it is, the more energy efficient it can be.
  • polymer solids have a viscoelastic relaxation mechanism, and large-scale molecular motion causes a decrease in storage elastic modulus (Young's modulus) (relaxation) or a maximum loss elastic modulus (absorption) as the temperature rises or the frequency decreases. Observed as. Among them, the relaxation caused by the micro-Brownian motion of the molecular chain in the amorphous region is called main dispersion, and a very large relaxation phenomenon is observed. The temperature at which this main dispersion occurs is the glass transition point (Tg), and the viscoelastic relaxation mechanism appears most prominently.
  • Tg glass transition point
  • the polymer composite piezoelectric body (piezoelectric layer 20), by using a polymer material having a glass transition point at room temperature, in other words, a polymer material having viscoelasticity at room temperature, for vibration of 20 Hz to 20 kHz.
  • a polymer composite piezoelectric material that is hard and behaves softly against slow vibrations of several Hz or less is realized.
  • the polymer material having viscoelasticity at room temperature various known materials can be used.
  • a polymer material having a maximum value of tangent Tan ⁇ at a frequency of 1 Hz by a dynamic viscoelasticity test of 0.5 or more is used at room temperature, that is, at 0 to 50 ° C.
  • the polymer material having viscoelasticity at room temperature preferably has a storage elastic modulus (E') at a frequency of 1 Hz by dynamic viscoelasticity measurement of 100 MPa or more at 0 ° C. and 10 MPa or less at 50 ° C.
  • E' storage elastic modulus
  • the polymer material having viscoelasticity at room temperature is more preferably having a relative permittivity of 10 or more at 25 ° C.
  • a voltage is applied to the polymer composite piezoelectric body, a higher electric field is applied to the piezoelectric particles in the polymer matrix, so that a large amount of deformation can be expected.
  • the polymer material has a relative permittivity of 10 or less at 25 ° C.
  • polymer material having viscoelasticity at room temperature satisfying such conditions examples include cyanoethylated polyvinyl alcohol (cyanoethylated PVA), polyvinyl acetate, polyvinylidene chloride core acrylonitrile, polystyrene-vinyl polyisoprene block copolymer, and polyvinylmethyl. Examples thereof include ketones and polybutyl methacrylate. Further, as these polymer materials, commercially available products such as Hybler 5127 (manufactured by Kuraray Co., Ltd.) can also be preferably used.
  • Hybler 5127 manufactured by Kuraray Co., Ltd.
  • the polymer material it is preferable to use a material having a cyanoethyl group, and it is particularly preferable to use cyanoethylated PVA.
  • these polymer materials may use only 1 type, and may use a plurality of types in combination (mixing).
  • a plurality of polymer materials may be used in combination, if necessary. That is, in addition to the viscoelastic material such as cyanoethylated PVA, other dielectric polymer materials may be added to the viscoelastic matrix 34 for the purpose of adjusting the dielectric properties and mechanical properties. ..
  • dielectric polymer material examples include polyvinylidene fluoride, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-trifluoroethylene copolymer, and vinylidene fluoride-trifluoroethylene copolymer.
  • fluoropolymers such as polyvinylidene fluoride-tetrafluoroethylene copolymer, vinylidene cyanide-vinyl acetate copolymer, cyanoethyl cellulose, cyanoethyl hydroxysaccharose, cyanoethyl hydroxycellulose, cyanoethyl hydroxypurrane, cyanoethyl methacrylate, cyanoethyl acrylate, cyanoethyl.
  • Cyano groups such as hydroxyethyl cellulose, cyanoethyl amylose, cyanoethyl hydroxypropyl cellulose, cyanoethyl dihydroxypropyl cellulose, cyanoethyl hydroxypropyl amylose, cyanoethyl polyacrylamide, cyanoethyl polyacrylate, cyanoethyl pullulan, cyanoethyl polyhydroxymethylene, cyanoethyl glycidol pullulan, cyanoethyl saccharose and cyanoethyl sorbitol.
  • polymers having a cyanoethyl group synthetic rubbers such as nitrile rubber and chloroprene rubber, and the like are exemplified. Among them, a polymer material having a cyanoethyl group is preferably used. Further, in the viscoelastic matrix 34 of the piezoelectric layer 20, the dielectric polymer added in addition to the material having viscoelasticity at room temperature such as cyanoethylated PVA is not limited to one type, and a plurality of types are added. May be good.
  • the viscoelastic matrix 34 contains a thermoplastic resin such as vinyl chloride resin, polyethylene, polystyrene, methacrylic resin, polybutene, and isobutylene for the purpose of adjusting the glass transition point Tg.
  • a thermoplastic resin such as vinyl chloride resin, polyethylene, polystyrene, methacrylic resin, polybutene, and isobutylene
  • a phenol resin, a urea resin, a melamine resin, an alkyd resin, and a thermocurable resin such as mica may be added.
  • a tackifier such as rosin ester, rosin, terpene, terpene phenol, and petroleum resin may be added.
  • the amount added when a material other than the polymer material having viscoelasticity such as cyanoethylated PVA is added is not particularly limited, but is a ratio to the viscoelastic matrix 34. It is preferably 30% by mass or less.
  • the characteristics of the polymer material to be added can be exhibited without impairing the viscoelastic relaxation mechanism in the viscoelastic matrix 34, so that the dielectric constant is increased, the heat resistance is improved, and the adhesion to the piezoelectric particles 36 and the electrode layer is increased. Preferred results can be obtained in terms of improvement and the like.
  • the piezoelectric particles 36 are made of ceramic particles having a perovskite-type or wurtzite-type crystal structure.
  • the ceramic particles constituting the piezoelectric particles 36 include lead zirconate titanate (PZT), lead lanthanate lanthanate titanate (PLZT), barium titanate (BaTIO 3 ), zinc oxide (ZnO), and the like.
  • PZT lead zirconate titanate
  • PLA 3 lead lanthanate lanthanate titanate
  • BaTIO 3 barium titanate
  • ZnO zinc oxide
  • Examples thereof include a solid solution (BFBT) of barium titanate and bismuth ferrite (BiFe 3).
  • the particle size of the piezoelectric particles 36 is not limited, and may be appropriately selected depending on the size of the piezoelectric film 12 and the application of the laminated piezoelectric element 10.
  • the particle size of the piezoelectric particles 36 is preferably 1 to 10 ⁇ m. By setting the particle size of the piezoelectric particles 36 in this range, favorable results can be obtained in that the piezoelectric film 12 can achieve both high piezoelectric characteristics and flexibility.
  • the piezoelectric particles 36 in the piezoelectric layer 20 are uniformly and regularly dispersed in the viscoelastic matrix 34, but the present invention is not limited to this. That is, the piezoelectric particles 36 in the piezoelectric layer 20 may be irregularly dispersed in the viscoelastic matrix 34 as long as they are preferably uniformly dispersed.
  • the amount ratio of the viscoelastic matrix 34 to the piezoelectric particles 36 in the piezoelectric layer 20 is not limited, and the size and thickness of the piezoelectric film 12 in the plane direction and the use of the laminated piezoelectric element 10 , And the characteristics required for the piezoelectric film 12, etc., may be appropriately set.
  • the volume fraction of the piezoelectric particles 36 in the piezoelectric layer 20 is preferably 30 to 80%, more preferably 50% or more, and therefore more preferably 50 to 80%.
  • the above-mentioned piezoelectric film 12 is preferably a polymer composite piezoelectric layer in which the piezoelectric layer 20 is formed by dispersing piezoelectric particles in a viscoelastic matrix containing a polymer material having viscoelasticity at room temperature.
  • the present invention is not limited to this, and various known piezoelectric layers used in known piezoelectric elements can be used as the piezoelectric layer of the piezoelectric film.
  • a piezoelectric layer made of the above-mentioned dielectric polymer material of polyvinylidene fluoride (PVDF) and vinylidene fluoride-tetrafluoroethylene copolymer, and PZT, PLZT, barium titanate, zinc oxide, BFBT and the like. Examples thereof include a piezoelectric layer made of the above-mentioned piezoelectric material.
  • the thickness of the piezoelectric layer 20 is not particularly limited, and depends on the application of the laminated piezoelectric element 10, the number of laminated piezoelectric films in the laminated piezoelectric element 10, the characteristics required for the piezoelectric film 12, and the like. , It may be set as appropriate.
  • the thickness of the piezoelectric layer 20 is preferably 10 to 300 ⁇ m, more preferably 20 to 200 ⁇ m, and even more preferably 30 to 150 ⁇ m.
  • the piezoelectric film 12 of the illustrated example has a first electrode layer 24 on one surface of such a piezoelectric layer 20, a first protective layer 28 on the first electrode layer 24, and is a piezoelectric layer.
  • the other surface of the 20 has a second electrode layer 26 and a second protective layer 30 on the second electrode layer 26.
  • the second electrode layer 26 and the first electrode layer 24 form an electrode pair.
  • the piezoelectric film 12 may have, for example, an insulating layer or the like that covers a region such as a side surface where the piezoelectric layer 20 is exposed to prevent a short circuit or the like.
  • the piezoelectric film 12 sandwiches both sides of the piezoelectric layer 20 between electrode pairs, that is, the first electrode layer 24 and the second electrode layer 26, and this laminated body is sandwiched between the first protective layer 28 and the second protective layer 30. It has a structure that is sandwiched between.
  • the region held by the first electrode layer 24 and the second electrode layer 26 is expanded and contracted according to the applied voltage.
  • the first electrode layer 24 and the first protective layer 28, and the second electrode layer 26 and the second protective layer 30 are named according to the polarization direction of the piezoelectric layer 20. Is. Therefore, the first electrode layer 24 and the second electrode layer 26, and the first protective layer 28 and the second protective layer 30 have basically the same configuration.
  • the first protective layer 28 and the second protective layer 30 have a role of covering the second electrode layer 26 and the first electrode layer 24 and imparting appropriate rigidity and mechanical strength to the piezoelectric layer 20. Is responsible for. That is, in the piezoelectric film 12, the piezoelectric layer 20 composed of the viscoelastic matrix 34 and the piezoelectric particles 36 exhibits extremely excellent flexibility against slow bending deformation, but depending on the application. , Rigidity and mechanical strength may be insufficient.
  • the piezoelectric film 12 is provided with a first protective layer 28 and a second protective layer 30 to supplement the piezoelectric film 12.
  • the first protective layer 28 and the second protective layer 30 are not limited, and various sheet-like materials can be used.
  • various resin films are preferably exemplified.
  • PET polyethylene terephthalate
  • PP polypropylene
  • PS polystyrene
  • PC polycarbonate
  • PPS polyphenylene sulfide
  • PMMA polymethylmethacrylate
  • PEI Polyetherimide
  • PEI polyimide
  • PEN polyethylene naphthalate
  • TAC triacetyl cellulose
  • a resin film made of a cyclic olefin resin or the like are preferably used.
  • the thickness of the first protective layer 28 and the second protective layer 30 there is no limitation on the thickness of the first protective layer 28 and the second protective layer 30. Further, the thicknesses of the first protective layer 28 and the second protective layer 30 are basically the same, but may be different. Here, if the rigidity of the first protective layer 28 and the second protective layer 30 is too high, not only the expansion and contraction of the piezoelectric layer 20 is restrained, but also the flexibility is impaired. Therefore, the thinner the first protective layer 28 and the second protective layer 30, the more advantageous it is, except when mechanical strength and good handleability as a sheet-like material are required.
  • the thickness of the first protective layer 28 and the second protective layer 30 is twice or less the thickness of the piezoelectric layer 20, it is possible to ensure both rigidity and appropriate flexibility. A favorable result can be obtained in terms of points.
  • the thickness of the first protective layer 28 and the second protective layer 30 is preferably 100 ⁇ m or less. 50 ⁇ m or less is more preferable, and 25 ⁇ m or less is further preferable.
  • a first electrode layer 24 is provided between the piezoelectric layer 20 and the first protective layer 28, and a second electrode layer 26 is provided between the piezoelectric layer 20 and the second protective layer 30. It is formed.
  • the first electrode layer 24 and the second electrode layer 26 are provided to apply a voltage to the piezoelectric layer 20 (piezoelectric film 12).
  • the materials for forming the first electrode layer 24 and the second electrode layer 26 are not limited, and various conductors can be used. Specifically, metals such as carbon, palladium, iron, tin, aluminum, nickel, platinum, gold, silver, copper, titanium, chromium and molybdenum, alloys thereof, laminates and composites of these metals and alloys, In addition, indium tin oxide and the like are exemplified. Among them, copper, aluminum, gold, silver, platinum, and indium tin oxide are preferably exemplified as the first electrode layer 24 and the second electrode layer 26.
  • first electrode layer 24 and the second electrode layer 26 are formed by a vapor deposition method (vacuum film deposition method) such as vacuum deposition and sputtering, a film formation by plating, or the above materials.
  • a vapor deposition method vacuum film deposition method
  • Various known methods such as a method of attaching a foil are available.
  • thin films such as copper and aluminum formed by vacuum deposition are preferably used as the first electrode layer 24 and the second electrode layer 26 because the flexibility of the piezoelectric film 12 can be ensured.
  • NS a copper thin film produced by vacuum deposition is preferably used.
  • the thickness of the first electrode layer 24 and the second electrode layer 26 There is no limitation on the thickness of the first electrode layer 24 and the second electrode layer 26. Further, the thicknesses of the first electrode layer 24 and the second electrode layer 26 are basically the same, but may be different.
  • the rigidity of the first electrode layer 24 and the second electrode layer 26 is too high, not only the expansion and contraction of the piezoelectric layer 20 is restrained, but also the expansion and contraction of the piezoelectric layer 20 is restricted. Flexibility is also impaired. Therefore, the thinner the first electrode layer 24 and the second electrode layer 26 are, the more advantageous they are, as long as the electrical resistance does not become too high.
  • the product of the thickness of the first electrode layer 24 and the second electrode layer 26 and the Young's modulus is less than the product of the thickness of the first protective layer 28 and the second protective layer 30 and the Young's modulus.
  • the thickness of the first protective layer 28 and the second protective layer 30 is 25 ⁇ m
  • the thickness of the first electrode layer 24 and the second electrode layer 26 is preferably 1.2 ⁇ m or less, more preferably 0.3 ⁇ m or less. Above all, it is preferably 0.1 ⁇ m or less.
  • the piezoelectric film 12 includes a piezoelectric layer 20 in which piezoelectric particles 36 are dispersed in a viscoelastic matrix 34 containing a polymer material having viscoelasticity at room temperature, and a first electrode layer 24 and a second electrode. It has a structure in which the first protective layer 28 and the second protective layer 30 are sandwiched between the layers 26 and the laminated body.
  • the maximum value of the loss tangent (Tan ⁇ ) at a frequency of 1 Hz by dynamic viscoelasticity measurement exists at room temperature, and the maximum value of 0.1 or more exists at room temperature. More preferred.
  • the piezoelectric film 12 is subjected to a relatively slow and large bending deformation of several Hz or less from the outside, the strain energy can be effectively diffused to the outside as heat. It is possible to prevent cracks from occurring at the interface of.
  • the piezoelectric film 12 preferably has a storage elastic modulus (E') at a frequency of 1 Hz as measured by dynamic viscoelasticity measurement of 10 to 30 GPa at 0 ° C. and 1 to 10 GPa at 50 ° C.
  • E' storage elastic modulus
  • the piezoelectric film 12 can have a large frequency dispersion in the storage elastic modulus (E') at room temperature. That is, it can behave hard for vibrations of 20 Hz to 20 kHz and soft for vibrations of several Hz or less.
  • the product of the thickness and the storage elastic modulus (E') at a frequency of 1 Hz measured by dynamic viscoelasticity is 1.0 ⁇ 10 6 to 2.0 ⁇ 10 6 N / m at 0 ° C. , It is preferably 1.0 ⁇ 10 5 to 1.0 ⁇ 10 6 N / m at 50 ° C.
  • the piezoelectric film 12 can be provided with appropriate rigidity and mechanical strength as long as the flexibility and acoustic characteristics are not impaired.
  • the piezoelectric film 12 preferably has a loss tangent (Tan ⁇ ) of 0.05 or more at 25 ° C. and a frequency of 1 kHz in the master curve obtained from the dynamic viscoelasticity measurement.
  • Ton ⁇ loss tangent
  • the frequency characteristics of the speaker using the piezoelectric film 12 become smooth, and the amount of change in sound quality when the minimum resonance frequency f 0 changes with the change in the curvature of the speaker can be reduced.
  • a sheet-like object 11a in which the first electrode layer 24 is formed on the first protective layer 28 is prepared.
  • the sheet-like material 11a may be produced by forming a copper thin film or the like as the first electrode layer 24 on the surface of the first protective layer 28 by vacuum deposition, sputtering, plating or the like.
  • the first protective layer 28 with a separator temporary support
  • PET or the like having a thickness of 25 to 100 ⁇ m can be used.
  • the separator may be removed after the second electrode layer 26 and the second protective layer 30 are thermocompression bonded, and before any member is laminated on the first protective layer 28.
  • a polymer material having viscoelasticity at room temperature such as cyanoethylated PVA is dissolved in an organic solvent, and piezoelectric particles 36 such as PZT particles are further added and stirred to prepare a dispersed coating material. ..
  • a polymer material having viscoelasticity at room temperature such as cyanoethylated PVA
  • the organic solvent is not limited, and various organic solvents such as dimethylformamide (DMF), methylethylketone, and cyclohexanone can be used.
  • the casting method of this paint is not particularly limited, and all known coating methods (coating devices) such as a slide coater and a doctor knife can be used.
  • the viscoelastic material is a material that can be heated and melted, such as cyanoethylated PVA, the viscoelastic material is heated and melted to prepare a molten product in which the piezoelectric particles 36 are added / dispersed, and then extruded.
  • the first electrode layer 24 is provided on the first protective layer 28 as shown in FIG. 4 by extruding the sheet-like material 11a shown in FIG. 3 into a sheet shape and cooling the sheet-like material 11a.
  • a laminated body 11b formed by forming a piezoelectric layer 20 on one electrode layer 24 may be produced.
  • a polymer piezoelectric material such as PVDF may be added to the viscoelastic matrix 34 in addition to the viscoelastic material such as cyanoethylated PVA.
  • the polymer piezoelectric materials to be added to the paint described above may be dissolved.
  • the polymer piezoelectric material to be added may be added to the above-mentioned heat-melted viscoelastic material and heat-melted.
  • a rod-like or wire-like shape that can be moved along the upper surface 20a with a gap g of, for example, 1 mm is formed on the upper surface 20a of the piezoelectric layer 20 of the laminated body 11b.
  • Corona electrode 40 is provided. Then, the corona electrode 40 and the first electrode layer 24 are connected to the DC power supply 42. Further, a heating means for heating and holding the laminated body 11b, for example, a hot plate is prepared.
  • the piezoelectric layer 20 is heated and held at a temperature of, for example, 100 ° C. by a heating means, and several kV, for example, 6 kV is generated between the DC power supply 42 and the first electrode layer 24 and the corona electrode 40. DC voltage is applied to cause corona discharge. Further, the corona electrode 40 is moved (scanned) along the upper surface 20a of the piezoelectric layer 20 while maintaining the interval g to perform the polarization treatment of the piezoelectric layer 20. As a result, the piezoelectric layer 20 is polarized in the thickness direction. By this polarization treatment, the first electrode layer 24 side is set to the upstream side in the polarization direction.
  • the corona electrode 40 may be moved by using a known rod-shaped object moving means.
  • the polarization process using corona discharge is also referred to as corona polling process.
  • the corona polling process there is no limitation on the method of moving the corona electrode 40. That is, the corona electrode 40 may be fixed, a moving mechanism for moving the laminated body 11b may be provided, and the laminated body 11b may be moved to perform the polarization treatment.
  • a known sheet-like object moving means may be used as for the movement of the laminated body 11b.
  • the polarization processing is not limited to the corona polling processing, and ordinary electric field polling in which a DC electric field is directly applied to the object to be polarized can also be used. However, when performing this normal electric field polling, it is necessary to form the second electrode layer 26 before the polarization treatment.
  • the sheet-like material 11c in which the second electrode layer 26 is formed on the second protective layer 30 is prepared.
  • the sheet-like material 11c may be produced by forming a copper thin film or the like as the second electrode layer 26 on the surface of the second protective layer 30 by vacuum vapor deposition, sputtering, plating or the like.
  • the second electrode layer 26 is directed toward the piezoelectric layer 20, and the sheet-like material 11c is laminated on the laminated body 11b that has completed the polarization treatment of the piezoelectric layer 20.
  • the laminated body of the laminated body 11b and the sheet-like material 11c is sandwiched between the second protective layer 30 and the first protective layer 28, and thermocompression bonding is performed by a heating press device or a heating roller or the like. Then, it is cut into a desired shape to produce a piezoelectric film 12 having a protruding portion 15.
  • the steps up to this point can be performed using a web-shaped sheet, that is, a wound sheet in a state where the sheets are connected for a long time, even if the sheet is not in the form of a sheet.
  • Both the laminate 11b and the sheet-like material 11c are in the form of a web, and can be thermocompression-bonded as described above. In that case, the piezoelectric film 12 is made into a web shape at this point.
  • a special glue layer may be provided when the laminated body 11b and the sheet-like material 11c are bonded together.
  • a glue layer may be provided on the surface of the second electrode layer 26 of the sheet-shaped 11c.
  • the most suitable glue layer is the same material as the viscoelastic matrix 34. It is also possible to apply the same material to the surface of the second electrode layer 26 and bond them together.
  • the laminated piezoelectric element 10 of the present invention has a structure in which such a piezoelectric film 12 is laminated and attached with an adhesive layer 14.
  • the polarization directions of the adjacent piezoelectric films 12 are opposite to each other.
  • the polarization directions of the adjacent piezoelectric films 12 are reversed from each other, three layers of piezoelectric films 12 are laminated, and the adjacent piezoelectric films 12 are attached by the adhesive layer 14.
  • the first layer piezoelectric film 12a in FIG. 1 has a downward polarization direction as shown by an arrow in the figure. Therefore, the first electrode layer 24 and the first protective layer 28 are arranged on the upper side in FIG. 1, and the second electrode 26 and the second protective layer 30 are arranged on the lower side in FIG. Further, the second layer piezoelectric film 12b arranged adjacent to the surface of the first layer piezoelectric film 12a on the second protective layer 30 side has an upward polarization direction as shown by an arrow in the figure. .. Therefore, the first electrode layer 24 and the first protective layer 28 are arranged on the lower side in FIG. 1, and the second electrode 26 and the second protective layer 30 are arranged on the upper side in FIG.
  • the third layer piezoelectric film 12c arranged adjacent to the surface of the second layer piezoelectric film 12b on the first protective layer 28 side has a downward polarization direction as shown by an arrow in the figure. .. Therefore, the first electrode layer 24 and the first protective layer 28 are arranged on the upper side in FIG. 1, and the second electrode 26 and the second protective layer 30 are arranged on the lower side in FIG.
  • each piezoelectric film is adhered to an adhesive portion to be adhered to the adjacent piezoelectric film and to the adjacent piezoelectric film protruding outward in the plane direction from the adhesive portion.
  • the first layer piezoelectric film 12a and the second layer piezoelectric film 12b have regions other than the left end portion in FIG. 1 bonded by the adhesive layer 14, and the region other than the left end portion in FIG. 1 is bonded by the adhesive layer 14. The edge area is not glued.
  • the region of each piezoelectric film that is adhered to the adjacent piezoelectric film is referred to as the adhesive portion 13, and the region that is not adhered is referred to as the protruding portion 15. It can be said that the protruding portion 15 is a region protruding outward from the adhesive portion 13 in the surface direction of the main surface of the piezoelectric film.
  • regions other than the left end portion in FIG. 1 are adhered by the adhesive layer 14, and the region of the left end portion in FIG. 1 is adhered. Is not glued.
  • An electrical contact is provided on the protruding portion 15 of each piezoelectric film.
  • a hole portion 28a penetrating the first protective layer 28 is formed, and a hole portion 30a penetrating the second protective layer 30 is formed.
  • the first electrode portion 24 is exposed by forming the hole portion 28a in the first protective layer 28. Further, the protruding portion 15 is not adhered to the adjacent piezoelectric film. Therefore, wiring or the like can be connected to the first electrode layer 24 in the hole 28a.
  • the hole portion 28a (the first electrode layer 24 in the hole portion 28a) is also referred to as a first contact point.
  • the second electrode portion 26 is exposed by forming the hole portion 30a in the second protective layer 30. Further, the protruding portion 15 is not adhered to the adjacent piezoelectric film. Therefore, wiring or the like can be connected to the second electrode layer 26 in the hole portion 30a.
  • the hole portion 30a (the second electrode layer 26 in the hole portion 30a) is also referred to as a second contact point.
  • the first layer piezoelectric film 12a is arranged so that the first electrode layer 24 side is on the upper side in FIG. 1, the first contact 28a and the lower side are on the upper surface of the protrusion 15.
  • the surface of the second contact 30a is provided.
  • the second-layer piezoelectric film 12b is arranged so that the first electrode layer 24 side is on the lower side in FIG. 1, the second contact 30a is on the upper surface of the protrusion 15 and the first is on the lower surface. It has a contact 28a.
  • the third-layer piezoelectric film 12c is arranged so that the first electrode layer 24 side is on the upper side in FIG.
  • the first contact 28a is on the upper surface of the protrusion 15 and the second contact 30a is on the lower surface.
  • the vertical direction in the above description corresponds to the vertical direction in FIG. 1, and the upper piezoelectric film in the drawing is the first layer piezoelectric film, and the first layer piezoelectric film side is the upper side. This point is the same in the following description.
  • the first contacts 28a provided on the protruding portions 15 of the piezoelectric films are connected to each other, and the second contacts 30a are connected to each other. ..
  • the first contact 28a is connected positively and the second contact 30a is connected negatively, but the first contact 28a is connected to the same polarity of the power supply, and the first contact 28a is connected to the same polarity.
  • the second contacts 30a are connected to each other with the same polarity of the other of the power supplies. For example, when connected to an AC power supply, all first contacts 28a are connected to one polarity of the AC power supply, and all second contacts 30a are connected to the other polarity of the AC power supply.
  • a power source for applying a driving voltage for expanding and contracting the piezoelectric film 12 is connected to the first electrode layer 24 and the second electrode layer 26 of each piezoelectric film 12 via the first contact 28a and the second contact 30a.
  • the power supply is not limited and may be a DC power supply or an AC power supply.
  • the drive voltage capable of appropriately driving each piezoelectric film may be appropriately set according to the thickness of the piezoelectric layer 20 of each piezoelectric film, the forming material, and the like.
  • the output of the laminated piezoelectric element decreases depending on the direction of polarization of the piezoelectric layer of the piezoelectric film and the direction of electrode polarity. In some cases, it did not deform as a whole.
  • one piezoelectric film is used in a certain phase when a voltage is applied. The film shrinks and the other piezoelectric film stretches. That is, the expansion and contraction behaviors of the two piezoelectric films are out of phase. Therefore, the expansion and contraction of the piezoelectric film cancel each other out, and the deformation of the laminated piezoelectric element as a whole is reduced.
  • the electrode layer is too thick, the deformation of the piezoelectric layer is hindered and the output is reduced, so that the electrode layer is formed very thin.
  • the electrode layer is provided in a state of being formed on the protective layer serving as a support in order to form the piezoelectric layer sandwiched between the thin electrode layers. Therefore, the outermost layers on both main surfaces of the piezoelectric film serve as protective layers, and there is a problem that it is difficult to secure electrical contacts to the electrode layers.
  • the first electrode 24 is arranged on the upstream side in the polarization direction of the piezoelectric layer 20, and the second electrode 26 is arranged on the downstream side.
  • the film has a protrusion 15 that is not adhered to an adjacent piezoelectric film, and the protrusion 15 of each piezoelectric film has a first contact 28a in which the first electrode layer 24 of each piezoelectric film is electrically connected to each other.
  • a second contact 30a is formed in which the second electrode layer 26 of each piezoelectric film is electrically connected to each other.
  • the protruding portion 15 that is not adhered to the adjacent piezoelectric film and providing the first contact 28a and the second contact 30a in the protruding portion 15, the first electrode layers 24 and the second electrode layers 26 are separated from each other. It can be easily connected.
  • each piezoelectric film by making the relationship between the polarization direction of each piezoelectric film and the polarity of the electrode layer the same for all piezoelectric films, it is possible to apply a voltage having the same phase to each piezoelectric film. That is, when a voltage is applied to the laminated piezoelectric element, the expansion and contraction behavior of all the piezoelectric films becomes in phase. Therefore, the expansion and contraction of each piezoelectric film can be strengthened, and the deformation (output) of the laminated piezoelectric element as a whole can be increased. That is, high piezoelectric characteristics can be obtained.
  • each piezoelectric film has a protective layer.
  • the following points can be mentioned as an advantage in forming an electric contact by providing a hole in the protective layer of the protrusion 15. If the polarization directions are opposite in adjacent layers, the contacts with the same electrical polarity will face each other. Therefore, since the parts other than the necessary contacts are insulated by the protective layer, there is an advantage that the protective layers come into contact with each other if the contact parts are shifted, and the insulation treatment becomes unnecessary. Further, when the polarization directions are the same in the adjacent layers, the electrode layers having different electric polarities face each other, but since there is a protective layer, the insulation treatment becomes unnecessary.
  • various known adhesive layers 14 can be used as long as the adjacent piezoelectric film 12 can be attached. Therefore, the adhesive layer 14 has fluidity when bonded, and then becomes a solid. Even a layer made of an adhesive is a soft solid gel-like (rubber-like) when bonded, and is subsequently gel-like. It may be a layer made of an adhesive that does not change the state of the above, or a layer made of a material having the characteristics of both an adhesive and an adhesive.
  • the laminated piezoelectric element 10 of the present invention vibrates the diaphragm 50 by expanding and contracting a plurality of laminated piezoelectric films, for example, as described later, to generate sound. Therefore, in the laminated piezoelectric element 10 of the present invention, it is preferable that the expansion and contraction of each piezoelectric film is directly transmitted. If a substance having a viscosity that alleviates vibration is present between the piezoelectric films, the efficiency of transmitting the expansion and contraction energy of the piezoelectric film is lowered, and the driving efficiency of the laminated piezoelectric element 10 is lowered.
  • the adhesive layer 14 is preferably an adhesive layer made of an adhesive, which can obtain a solid and hard adhesive layer 14 rather than an adhesive layer made of an adhesive.
  • an adhesive layer made of a thermoplastic type adhesive such as a polyester adhesive and a styrene-butadiene rubber (SBR) adhesive is preferably exemplified. Adhesion, unlike adhesion, is useful when seeking high adhesion temperatures. Further, the thermoplastic type adhesive has "relatively low temperature, short time, and strong adhesion" and is suitable.
  • the thickness of the adhesive layer 14 is not limited, and a thickness capable of exhibiting sufficient adhesive force (adhesive force, adhesive force) can be appropriately adjusted according to the material for forming the adhesive layer 14. , Just set it.
  • adhesive force adhesive force
  • the adhesive layer 14 is thick and has high rigidity, it may restrain the expansion and contraction of the piezoelectric film.
  • the adhesive layer 14 can be made thin. Considering this point, the adhesive layer 14 is preferably thinner than the piezoelectric layer 20. That is, in the laminated piezoelectric element 10 of the present invention, the adhesive layer 14 is preferably hard and thin. Specifically, the thickness of the adhesive layer 14 is preferably 0.1 to 50 ⁇ m, more preferably 0.1 to 30 ⁇ m, and even more preferably 0.1 to 10 ⁇ m after sticking.
  • the spring constant of the adhesive layer 14 is high, the expansion and contraction of the piezoelectric film 12 may be restricted. Therefore, the spring constant of the adhesive layer 14 is preferably equal to or less than the spring constant of the piezoelectric film 12.
  • the spring constant is "thickness x Young's modulus".
  • the product of the thickness of the adhesive layer 14 and the storage elastic modulus (E') at a frequency of 1 Hz by dynamic viscoelasticity measurement is 2.0 ⁇ 10 6 N / m or less at 0 ° C., 50 ° C. It is preferably 1.0 ⁇ 10 6 N / m or less.
  • the internal loss at a frequency of 1 Hz by the dynamic viscoelasticity measurement of the adhesive layer is 1.0 or less at 25 ° C. in the case of the adhesive layer 14 made of an adhesive, and in the case of the adhesive layer 14 made of an adhesive. It is preferably 0.1 or less at 25 ° C.
  • the laminated piezoelectric element 10 of the present invention is adhered to the diaphragm 50 by the adhesive layer 52 as an exciter for generating sound from the diaphragm 50, as conceptually shown in FIG. Used.
  • the diaphragm 50 and the laminated piezoelectric element 10 are in contact with each other and fixed via the bonding layer 52, and the laminated piezoelectric element 10 serves as an exciter for generating sound from the diaphragm 50.
  • FIG. 8 shows an example of the electroacoustic transducer of the present invention having the laminated piezoelectric element 10 of the present invention.
  • the piezoelectric layer 20 constituting the piezoelectric film in which a plurality of layers are laminated is formed by dispersing the piezoelectric particles 36 in the viscoelastic matrix 34. Further, the first electrode layer 24 and the second electrode layer 26 are provided so as to sandwich the piezoelectric layer 20 in the thickness direction.
  • the piezoelectric particles 36 expand and contract in the polarization direction according to the applied voltage.
  • the piezoelectric film shrinks in the thickness direction.
  • the piezoelectric film expands and contracts in the plane direction due to the pore ratio. This expansion and contraction is about 0.01 to 0.1%.
  • the thickness of the piezoelectric layer 20 is preferably about 10 to 300 ⁇ m. Therefore, the expansion and contraction in the thickness direction is very small, about 0.3 ⁇ m at the maximum.
  • the piezoelectric film that is, the piezoelectric layer 20
  • the piezoelectric film has a size much larger than the thickness in the plane direction. Therefore, for example, if the length of the piezoelectric film is 20 cm, the piezoelectric film expands and contracts by a maximum of about 0.2 mm when a voltage is applied.
  • the diaphragm 50 is attached to the laminated piezoelectric element 10 by the adhesive layer 52. Therefore, the expansion and contraction of the piezoelectric film causes the diaphragm 50 to bend, and as a result, the diaphragm 50 vibrates in the thickness direction.
  • the diaphragm 50 emits a sound due to the vibration in the thickness direction. That is, the diaphragm 50 vibrates according to the magnitude of the voltage (driving voltage) applied to the piezoelectric film, and generates a sound corresponding to the driving voltage applied to the piezoelectric film.
  • a general piezoelectric film made of a polymer material such as PVDF the molecular chains are oriented with respect to the stretching direction by stretching in the uniaxial direction after the polarization treatment, and as a result, a large piezoelectric property is exhibited in the stretching direction. It is known to be obtained. Therefore, a general piezoelectric film has in-plane anisotropy in the piezoelectric characteristics, and has anisotropy in the amount of expansion and contraction in the plane direction when a voltage is applied.
  • a piezoelectric film having a polymer composite piezoelectric body in which piezoelectric particles are dispersed in a viscoelastic matrix can obtain large piezoelectric characteristics without stretching treatment after polarization treatment, so that the piezoelectric characteristics are in-plane. It has no anisotropy and expands and contracts isotropically in all directions in the plane direction. That is, the piezoelectric film expands and contracts isotropically and two-dimensionally.
  • the laminated piezoelectric element 10 in which such an isotropically two-dimensionally expanding and contracting piezoelectric film is laminated vibrates with a larger force than when a general piezoelectric film such as PVDF that expands and contracts greatly in only one direction is laminated.
  • the plate 50 can be vibrated, and a louder and more beautiful sound can be generated.
  • the laminated piezoelectric element of the present invention is obtained by laminating a plurality of such piezoelectric films. Therefore, even if the rigidity of each piezoelectric film is low and the elastic force is small, the rigidity is increased by laminating the piezoelectric films, and the elastic force of the laminated piezoelectric element 10 is increased. As a result, in the laminated piezoelectric element 10 of the present invention, even if the diaphragm 50 has a certain degree of rigidity, the diaphragm 50 is sufficiently bent with a large force to sufficiently bend the diaphragm 50 in the thickness direction. It can be vibrated to generate sound in the diaphragm 50.
  • the preferable thickness of the piezoelectric layer 20 is about 300 ⁇ m at the maximum, so that even if the voltage applied to each piezoelectric film is small, it is sufficient. , The piezoelectric film can be expanded and contracted.
  • the adhesive layer 52 for attaching the laminated piezoelectric element 10 and the diaphragm 50 is not limited, and various known pressure-sensitive adhesives and adhesives are used. Is available. As an example, the same as the above-mentioned adhesive layer 14 is exemplified.
  • the preferred sticking layer 52 (sticking agent) is also the same as the sticking layer 14.
  • the diaphragm 50 is not limited, and various articles can be used.
  • the vibrating plate 50 include plate materials such as resin plates and glass plates, advertising media such as signs, office equipment and furniture such as tables, whiteboards and projection screens, and organic electroluminescence (OLED (Organic)).
  • OLED Organic electroluminescence
  • Display devices such as displays and liquid crystal displays, vehicle members such as consoles, A-pillars, ceilings and bumpers, and building materials such as walls of houses are exemplified.
  • the diaphragm 50 to which the laminated piezoelectric element 10 of the present invention is attached preferably has flexibility, and more preferably windable.
  • a flexible panel-shaped display device such as a flexible display panel is particularly preferably exemplified. Further, it is more preferable that the display device can also be wound up.
  • the electroacoustic converter of the present invention responds to the winding curvature of the diaphragm 50 so that the laminated piezoelectric element 10 does not peel off from the diaphragm 50 when the diaphragm 50 is wound.
  • the laminated piezoelectric element 10 also bends together with the diaphragm 50. Since the piezoelectric film 12 has suitable flexibility, the laminated piezoelectric element 10 of the present invention also basically exhibits good flexibility. At this time, the winding curvature of the diaphragm 50 is basically a specific curvature, but the winding curvature of the diaphragm 50 may be variable.
  • the display device when the display device is a diaphragm 50, the laminated piezoelectric element 10 is attached to the back side of the display device, that is, the non-image display surface side of the display device. preferable.
  • the size of the sticking layer 52 in the plane direction is preferably the same size as or smaller than the size of the planar shape of the laminated piezoelectric element 10.
  • the display device when the display device is used as the diaphragm 50, the display device itself such as a flexible display panel may be used as the diaphragm 50, or a plate-shaped display device provided in the display device.
  • the plate-shaped member that engages with the member or the display device may be the diaphragm 50.
  • the electroacoustic converter of the present invention when used as a display device, the electroacoustic converter of the present invention may be incorporated in the display device, or the diaphragm 50 of the electroacoustic converter of the present invention may be used as a display device.
  • the plate-shaped member provided in the above may be vibrated, or the electroacoustic converter of the present invention may be incorporated in a casing or the like together with the display device.
  • the diaphragm 50 when the diaphragm 50 can be wound up, a drive current is applied to the laminated piezoelectric element 10 in a state where the diaphragm 50 is not wound up, and the diaphragm 50 is wound up. At that time, it is preferable that the laminated piezoelectric element 10 is not energized. Further, in the electroacoustic converter of the present invention, when the diaphragm 50 is electrically driven like a display device, the laminated piezoelectric element 10 and / or the diaphragm without winding the diaphragm 50.
  • the drive current When the drive current is applied to the 50 and the diaphragm 50 is wound, it is preferable not to energize the laminated piezoelectric element 10 and / or the diaphragm 50.
  • a method for switching between energization and de-energization various known methods can be used.
  • the electroacoustic transducer of the present invention is formed by attaching (fixing) the laminated piezoelectric element 10 to the diaphragm 50 by using the attachment layer 52.
  • the end portion (end side) of the diaphragm 50 may be fixed to a wall or the like, and / or the end portion may be fixed by a fixing means such as a beam.
  • the shape of the diaphragm 50 is not limited, but it is often a quadrangle.
  • a display device such as an organic electroluminescence display can be suitably used as the diaphragm 50.
  • the diaphragm 50 is usually rectangular.
  • the diaphragm 50 is a rectangle such as a rectangle or a square
  • the two opposite sides are fixed by the fixing means 80 as conceptually shown in FIG. 45.
  • the diaphragm 50 is often supported.
  • the distance between the two fixing means 80 for fixing the two opposite sides of the rectangular diaphragm 50 that is, the distance between the fixed ends of the diaphragm 50 is L.
  • the laminated piezoelectric element 10 is attached to the diaphragm 50 at a distance of 0.1 ⁇ L or more.
  • the fixing of the diaphragm 50 suppresses the expansion and contraction of the laminated piezoelectric element 10 described above, and the diaphragm 50 is vibrated more preferably to produce a sound having a higher sound pressure. It becomes possible to output.
  • the end portion of the laminated piezoelectric element 10 projects outward from the adhesive layer 52 in the plane direction, the end portion of the adhesive layer 52 is laminated piezoelectric. It is regarded as the end of the element 10. That is, at this time, the laminated piezoelectric element is attached so that the end portion of the adhesive layer 52 is separated from the fixed end of the diaphragm 50 by 0.1 ⁇ L or more. On the contrary, when the end portion of the laminated piezoelectric element 10 is located inside the adhesive layer 52 in the surface direction, the end portion of the laminated piezoelectric element 10 is separated from the fixed end of the diaphragm 50 by 0.1 ⁇ L or more. The laminated piezoelectric element may be attached so as to do so.
  • FIG. 49 shows a simulation result of the relationship between the distance from the fixed end of the diaphragm to the laminated piezoelectric element and the displacement of the diaphragm when laminated piezoelectric elements of various sizes are attached to the square diaphragm. show.
  • a stainless steel square plate having a size of 10 ⁇ 10 mm and a thickness of 0.3 mm was used, and the ends (end sides) of the two opposite sides were fixed.
  • a square piezoelectric film 12 shown in FIG. 2 was laminated in four layers, and each layer was attached by an attachment layer.
  • the laminated piezoelectric element was provided with a sticking layer on the entire surface, and the laminated piezoelectric element was stuck to the center of the diaphragm by matching the directions of the respective sides. Therefore, if the size of the laminated piezoelectric element is different, the distance from the fixed end of the diaphragm to the laminated piezoelectric element is different.
  • the area ratio of 100% is a case where the laminated piezoelectric element is attached to the entire surface from the fixed end to the fixed end of the diaphragm.
  • the area ratio of 60% is a case where the laminated piezoelectric element is attached to the diaphragm at a distance of 0.2 ⁇ L mm from the fixed end of the diaphragm, as shown in the upper part of FIG.
  • the area ratio of 20% is a case where the laminated piezoelectric element is attached to the diaphragm at a distance of 0.4 ⁇ L mm from the fixed end of the diaphragm, as shown in the lower part of FIG.
  • the broken line is the region where the laminated piezoelectric element does not exist in the diaphragm
  • the solid line is the region where the laminated piezoelectric element is attached to the diaphragm.
  • the area ratio is 100%, that is, when the laminated piezoelectric element is attached from the fixed end to the fixed end of the diaphragm, the displacement of the diaphragm, that is, the vibration is small.
  • the diaphragm can be vibrated sufficiently large by attaching the laminated piezoelectric element to the diaphragm at an area ratio of 80%, that is, 0.1 ⁇ L mm away from the fixed end of the diaphragm.
  • the diaphragm 50 when fixing the two opposite sides of the quadrangular diaphragm, the diaphragm is laminated on the diaphragm at a distance of 0.1 ⁇ L mm or more from the fixed end of the diaphragm. By attaching the element, it is possible to more preferably vibrate the diaphragm and output a sound having a higher sound pressure.
  • the fixing means 80 for fixing the side of the diaphragm 50 there is no limitation on the fixing means 80 for fixing the side of the diaphragm 50, and various known fixing means for fixing the side (end side) of the plate-shaped object (sheet-like object, film). Means are available.
  • a beam that can support the sides of a plate (including a cantilever), a fixing member used to support the sides of a projection screen, and a wound sheet such as a cartridge can be pulled out and
  • An example is a fixing mechanism for a sheet-like object provided at a sheet drawer port of a container that can be freely wound.
  • the fixing of the diaphragm 50 is not limited to the use of the fixing means 80.
  • the diaphragm 50 may be fixed by directly sticking the end portion (end face) of the diaphragm 50 to a wall, a plate-like object serving as a support, or the like using a sticking agent or the like. .. In this case, the end of the diaphragm becomes the fixed end of the diaphragm 50.
  • the electroacoustic transducer of the present invention is not limited to having one laminated piezoelectric element 10.
  • an electroacoustic converter when the sound is reproduced in stereo, that is, in two channels, as conceptually shown in FIG. 46, the distance between the fixed ends is separated in the L direction, and the two laminated piezoelectric elements 10 are separated. May be attached to the diaphragm 50.
  • the laminated piezoelectric element 10 is separated from the fixed end of the diaphragm 50 by 0.1 ⁇ L or more, where L is the distance between the two fixing means 80, that is, the distance between the fixed ends of the diaphragm 50. , It is preferable to attach it to the diaphragm 50.
  • all four sides of the rectangular (square) diaphragm 50 may be fixed, for example, like a picture frame.
  • the laminated piezoelectric element 10 corresponds to each of the fixing means 80a for fixing one opposite two sides and the fixing means 80b for fixing the other two opposing sides. It is preferable to determine the fixed position of.
  • the distance between the two fixing means 80a for fixing one of the opposing sides of the diaphragm 50 that is, between the fixed ends of the diaphragm 50 on the opposite sides. Let the distance be L1.
  • the distance between the two fixing means 80b for fixing the other opposite sides of the diaphragm 50 that is, the distance between the fixed ends of the diaphragm 50 on the opposite sides is defined as L2.
  • the diaphragm 50 is separated from the end of the fixing means 80a, that is, the fixed end by the fixing means 80a by 0.1 ⁇ L1 or more, and the end of the fixing means 80b, that is, the fixing. It is preferable to attach the laminated piezoelectric element 50 at a position separated from the fixed end by the means 80b by 0.1 ⁇ L2 or more.
  • the electroacoustic converter of the present invention even when all four sides of the rectangular diaphragm 50 are fixed, it is not limited to having only one laminated piezoelectric element 10.
  • audio may be reproduced in stereo and reproduced in 2.5 channels such as providing a center speaker.
  • two laminated piezoelectric elements 10 for stereo reproduction are provided in the vicinity of the ends in the direction of the distance L1 between the long fixed ends, and the center speaker is provided in the center.
  • the laminated piezoelectric element 10 for this purpose may be provided.
  • the laminated piezoelectric element 10 has a distance L1 between the fixed ends by the fixing means 80a for fixing one opposite side and a distance L2 between the fixed ends by the fixing means 80b for fixing the other opposite side.
  • three laminated piezoelectric elements 50 are attached at positions separated from the fixed end by the fixing means 80a by 0.1 ⁇ L1 or more and separated from the fixed end by the fixing means 80b by 0.1 ⁇ L2 or more. It is preferable to do so.
  • the laminated piezoelectric element 10 is attached to the diaphragm at a distance of 1 ⁇ L or more.
  • the distance from the fixed end of the diaphragm 50 to the laminated piezoelectric element 10 is more preferably 0.15 ⁇ L or more in terms of obtaining a higher sound pressure, that is, a displacement amount of the diaphragm 50, and 0. 2 ⁇ L or more is more preferable.
  • the laminated piezoelectric element 10 of a required size cannot be attached to the vibrating plate 50, and the required number of laminated piezoelectric elements 10 cannot be attached. Can not be attached to the vibrating plate 50, multi-channel reproduction such as stereo reproduction becomes difficult, and when the number of channels is increased, the distance between the laminated piezoelectric elements 10 is too close and cross talk may occur. There is sex. Considering this point, the distance from the fixed end of the diaphragm 50 to the laminated piezoelectric element 10 is preferably 0.4 ⁇ L or less, and more preferably 0.3 ⁇ L or less.
  • the effect of fixing the diaphragm 50 on the vibration of the diaphragm depends on the rigidity of the diaphragm 50, and the higher the rigidity of the diaphragm 50, the greater the influence. That is, the effect of separating the fixed position of the laminated piezoelectric element 10 from the fixed end of the diaphragm 50 can be obtained more when the rigidity of the diaphragm 50 is high. Considering this point, the two opposite sides of the rectangular diaphragm 50 are fixed, and the laminated piezoelectric element 10 is attached to the diaphragm 50 at a distance of 0.1 ⁇ L or more from the fixed end of the diaphragm 50.
  • the rigidity of the diaphragm 50 is high to some extent. Specifically, when the two opposing sides of the diaphragm 50 are fixed and the fixed position of the laminated piezoelectric element 10 is separated from the fixed end of the diaphragm 50 by 0.1 ⁇ L or more, the diaphragm 50
  • the spring constant is preferably 1 ⁇ 10 4 to 1 ⁇ 10 7 N / m, more preferably 1 ⁇ 10 5 to 1 ⁇ 10 6 N / m.
  • the spring constant of a plate-shaped object such as a diaphragm can be calculated by multiplying the Young's modulus of the forming material by the thickness of the plate-shaped object.
  • the shape of the diaphragm is not limited to rectangles and squares, and various quadrangles such as rhombuses, trapezoids, and parallelograms can be used.
  • the distance L between the fixed ends is set as in L1, L2, L3 ....
  • the laminated piezoelectric element 10 is separated from the fixed end by 0.1 ⁇ L1 or more, and when the distance between the fixed ends is L2, the laminated piezoelectric element 10 is separated.
  • the laminated piezoelectric element 10 is separated from the fixed end by 0.1 ⁇ L3 or more so as to be separated from the fixed end by 0.1 ⁇ L3 or more.
  • the attachment position of the laminated piezoelectric element 10 on the vibrating plate 50a may be determined.
  • the quadrangle of the diaphragm 50 is not limited to a perfect quadrangle. That is, in the present invention, the quadrangular diaphragm 50 may have a chamfered corner, a curved (R-shaped, round) corner, or an oval shape.
  • the fixing of the two opposing sides in the square diaphragm is not limited to the entire area of the side, and one of the sides depends on the rigidity of the diaphragm and the size of the diaphragm.
  • the area of the part may be fixed. In this case, it is preferable to fix a region of 50% or more of one side, more preferably a region of 70% or more of one side, and further fixing a region of 90% or more of one side. It is preferable to fix the entire area of one side, and it is particularly preferable to fix the entire area. Further, as described above, when the corners of the quadrangle are chamfered or curved, the area not chamfered may be the entire area of one side, or chamfered. It may be the entire area of one side including the area where the above is performed.
  • the shape of the diaphragm is not limited to a quadrangle, and diaphragms having various shapes such as a circle, an ellipse, and a polygon other than a quadrangle can be used.
  • diaphragms having various shapes such as a circle, an ellipse, and a polygon other than a quadrangle can be used.
  • the preferable effect that a high sound pressure or the like can be obtained by attaching the laminated piezoelectric element 10 to the diaphragm at a certain distance from the fixed end of the diaphragm is a preferable effect.
  • various diaphragms other than the square shape regardless of the shape of the diaphragm.
  • the diaphragm has a polygonal shape having opposite sides such as a hexagon and an octagon
  • fixing is performed on the two opposing sides, and the fixed ends are fixed as in the case of the quadrangular diaphragm 50.
  • the circular diaphragm 50b as conceptually shown in FIG. 52, it is conceivable to provide a circular (annular) fixing means 80c so as to surround the entire circumference of the diaphragm 50b.
  • the inner diameter ⁇ of the fixing means 80c is set as the distance L between the fixed ends, and the position is 0.1 ⁇ L or more away from the fixed end of the diaphragm 50.
  • the laminated piezoelectric element 10 may be attached.
  • the circular diaphragm 50b as shown in FIG.
  • the diaphragm is an arc-shaped fixing means such as the fixing means 80d and the fixing means 80e which are overlapped with the annular fixing means 80c and shown by a hatch in FIG. It is also conceivable to fix 50b.
  • the laminated piezoelectric element 10 is attached at a position separated by 0.1 ⁇ L or more from the fixed end of the diaphragm 50b, where the inner diameter ⁇ of the arc of the fixing means is the distance L between the fixed ends. Just do it.
  • the diaphragm is a polygon with no opposite sides, such as a triangle or a pentagon. In this case, it is conceivable to fix one side of the polygon and the opposing vertices. For example, as conceptually shown in FIG. 53, when the diaphragm 50c is a triangle, it is conceivable to fix one side of the triangle with the fixing means 80 and fix the apex facing the one side with the fixing means 80f. Be done.
  • the perpendicular line P is lowered from the apex fixed by the fixing means 80f to the opposite side to be fixed, and the distance of the perpendicular line from the apex to the side to be fixed is defined as the distance L between the fixed ends, and the diaphragm 50c.
  • the laminated piezoelectric element 10 may be attached at a position separated from the fixed end (one of which is the apex) by 0.1 ⁇ L or more.
  • the polarization directions of the adjacent piezoelectric films are opposite to each other. That is, the piezoelectric films are laminated so that the polarization directions are alternated.
  • the present invention is not limited to this.
  • the polarization directions of the adjacent piezoelectric films may coincide with each other.
  • the first layer piezoelectric film 12d in FIG. 9 has a downward polarization direction as shown by an arrow in the figure. Therefore, the first electrode layer 24 and the first protective layer 28 are arranged on the upper side in FIG. 9, and the second electrode 26 and the second protective layer 30 are arranged on the lower side in FIG. Further, the second layer piezoelectric film 12e arranged adjacent to the surface of the first layer piezoelectric film 12d on the second protective layer 30 side has a downward polarization direction as shown by an arrow in the figure. .. Therefore, the first electrode layer 24 and the first protective layer 28 are arranged on the upper side in FIG. 9, and the second electrode 26 and the second protective layer 30 are arranged on the lower side in FIG.
  • the third layer piezoelectric film 12f arranged adjacent to the surface of the second layer piezoelectric film 12e on the second protective layer 30 side has a downward polarization direction as shown by an arrow in the figure. .. Therefore, the first electrode layer 24 and the first protective layer 28 are arranged on the upper side in FIG. 9, and the second electrode 26 and the second protective layer 30 are arranged on the lower side in FIG.
  • the first piezoelectric film 12d is arranged so that the first electrode layer 24 side is on the upper side in FIG. 9, the first protective layer 28 is formed on the upper surface of the protrusion 15.
  • a hole serving as the first contact 28a is provided, and a hole serving as the second contact 30a is provided on the second protective layer 30 on the lower surface.
  • the second-layer piezoelectric film 12e is arranged so that the first electrode layer 24 side is on the upper side in FIG. 9, the first contact 28a is formed on the first protective layer 28 on the upper surface of the protruding portion 15.
  • a hole is provided, and a hole serving as a second contact 30a is provided in the second protective layer 30 on the lower surface.
  • the third-layer piezoelectric film 12f is arranged so that the first electrode layer 24 side is on the upper side in FIG. 9, the hole serving as the first contact 28a in the first protective layer 28 on the upper surface of the protruding portion 15. A portion is provided, and a hole portion serving as a second contact 30a is provided in the second protective layer 30 on the lower surface.
  • the first contacts 28a provided on the protruding portions 15 of the piezoelectric films are connected to each other, and the second contacts 30a are connected to each other.
  • the second electrode layers 26 face each other on one surface and the other.
  • the first electrode layers 24 face each other on the surface. Therefore, even if the electrode layers of adjacent piezoelectric films come into contact with each other, there is no risk of short-circuiting, which is preferable.
  • the adhesive layer 14 in order to expand and contract the laminated piezoelectric element 10 with good energy efficiency, it is preferable to make the adhesive layer 14 thin so that the adhesive layer 14 does not interfere with the expansion and contraction of the piezoelectric layer 20.
  • the laminated piezoelectric elements 10 in which the polarization directions of the piezoelectric layers 20 of the adjacent piezoelectric films are opposite to each other do not cause a short circuit even if the electrode layers of the adjacent piezoelectric films come into contact with each other.
  • the adhesive layer 14 can be made extremely thin. Therefore, the laminated piezoelectric element 10 can be expanded and contracted with higher energy efficiency.
  • the absolute amount of expansion and contraction of the piezoelectric layer 20 in the thickness direction is very small, and the expansion and contraction of the piezoelectric film is substantially only in the plane direction. Therefore, even if the polarization directions of the laminated piezoelectric films are opposite, all the piezoelectric films expand and contract in the same direction as long as the polarities of the voltages applied to the first electrode layer 24 and the second electrode layer 26 are correct.
  • the polarization direction of the piezoelectric film may be detected by a d33 meter or the like.
  • the polarization direction of the piezoelectric layer 20 may be known from the processing conditions of the corona polling process described above.
  • the adhesive layer to which the laminated piezoelectric element 10 and the diaphragm 50 are attached is not limited, and various known adhesives and adhesives can be used. .. As an example, the same as the above-mentioned adhesive layer 14 is exemplified.
  • the diaphragm 50 is not limited, and various articles can be used.
  • the vibrating plate 50 include plate materials such as resin plates and glass plates, advertising / announcement media such as signs, office equipment and furniture such as tables, whiteboards and projection screens, and organic electroluminescence (OLED (OLED).
  • OLED organic electroluminescence
  • Display devices such as displays and liquid crystal displays, vehicle members such as consoles, A-pillars, ceilings and bumpers, and building materials such as walls of houses are exemplified.
  • the laminated piezoelectric element 10 of the illustrated example preferably, a long (large area) piezoelectric film is produced, and the long piezoelectric film is cut into individual piezoelectric films. Therefore, in this case, the plurality of piezoelectric films constituting the laminated piezoelectric element 10 are all the same.
  • the present invention is not limited to this. That is, various configurations can be used for the laminated piezoelectric element of the present invention, for example, a configuration in which piezoelectric films having different layer configurations are laminated, and a configuration in which piezoelectric films having different thicknesses of the piezoelectric layer 20 are laminated. ..
  • FIG. 10 is a diagram conceptually showing an example of the laminated piezoelectric element of the present invention.
  • FIG. 11 is an exploded view of FIG.
  • FIG. 12 is a diagram showing a plurality of piezoelectric films included in the laminated piezoelectric element of FIG.
  • the examples shown in FIGS. 10 and 11 have a configuration in which five piezoelectric films are laminated.
  • the piezoelectric films are laminated so that the polarization directions alternate.
  • FIGS. 11 and 12 the surface of the piezoelectric film on the second protective layer side is shown with hatching. That is, in FIG. 11, the first layer piezoelectric film 12g in FIG.
  • the third-layer piezoelectric film 12i is laminated with the first protective layer 28 side facing up
  • the fourth-layer piezoelectric film 12j is laminated with the second protective layer 30 side facing up
  • the fifth layer of the piezoelectric film 12k is laminated with the first protective layer 28 side facing upward.
  • each piezoelectric film has a rectangular adhesive portion 13 and two projecting portions 15 projecting from the long side side of the adhesive portion 13 toward the outside in the surface direction.
  • the two projecting portions 15 are provided so as to project from the opposite long sides of the adhesive portion 13.
  • the size of the adhesive portion 13 of each piezoelectric film is substantially the same.
  • the first layer of the piezoelectric film 12g has a protruding portion 15 formed on one end side on the long side.
  • the protruding portion 15 is formed at a position deviated from the position of the protruding portion 15 of the first layer piezoelectric film 12g toward the other end side.
  • the protruding portion 15 is formed at a position deviated from the position of the protruding portion 15 of the second layer piezoelectric film 12h toward the other end side.
  • the protruding portion 15 is formed at a position deviated from the position of the protruding portion 15 of the third layer piezoelectric film 12i toward the other end side.
  • the protruding portion 15 is formed at a position deviated from the position of the protruding portion 15 of the fourth layer piezoelectric film 12j toward the other end side.
  • the protruding portions of the piezoelectric films have substantially the same size and shape. Further, the protruding portion of each piezoelectric film is formed at a position deviated by one protruding portion from the position of the protruding portion of the adjacent piezoelectric film.
  • a hole 28a penetrating the first protective layer 28 is provided in the protrusion 15 on one long side of each piezoelectric film, and the first electrode layer 24 is exposed in the hole 28a. ..
  • the protruding portion 15 on the other long side of each piezoelectric film is provided with a hole portion 30a penetrating the second protective layer 30, and the second electrode layer 26 is exposed in the hole portion 30a. .. That is, the first contact 28a is formed on the protruding portion 15 on one long side of each piezoelectric film, and the second contact 30a is formed on the protruding portion 15 on the other long side.
  • the protruding portions 15 of the piezoelectric films do not overlap each other in the surface direction. Be placed. Further, a first contact 28a is formed on each of the protruding portions 15 on the long side side (long side side on the right side in FIG. 11) of each piezoelectric film. As described above, since the piezoelectric films of the first, third, and fifth layers and the piezoelectric films of the second and fourth layers are laminated in opposite directions, the first contact 28a is formed on the surfaces opposite to each other.
  • a conductive film 60a is attached to the five protrusions 15 on which the first contact points 28a are formed from the front surface to the back surface. As a result, the first contact 28a of each piezoelectric film is easily electrically connected.
  • a second contact 30a is formed on each of the protruding portions 15 on the other long side side (the long side side on the left side in FIG. 11) of each piezoelectric film.
  • the second contact 30a is formed on the surfaces opposite to each other.
  • a conductive film 60b is attached to the five protrusions 15 on which the second contact points 30a are formed from the front surface to the back surface. As a result, the second contact 30a of each piezoelectric film is easily electrically connected.
  • the shapes of the hole 28a formed in the first protective layer 28 of the protrusion 15 and the hole 30a formed in the second protective layer 30 are not particularly limited as long as they can be reliably connected to the electrode layer. It can have various shapes such as a circular shape, an elliptical shape, a rectangular shape, a polygonal shape, and an indefinite shape.
  • the sizes of the hole 28a and the hole 30a are not particularly limited as long as they can be reliably connected to the electrode layer.
  • the diameter equivalent to a circle is preferably 0.5 mm to 10 mm, more preferably 1 mm to 5 mm.
  • the formation positions of the hole portion (first contact) 28a and the hole portion (second contact) 30a are not particularly limited, but each piezoelectric film can be easily connected to each other. It is preferable that the holes (first contact) 28a and the holes (second contact) 30a of the film are formed on the same side of the adhesive portion 13, respectively.
  • conductive films 60a and 60b sheet-like materials formed of a conductive metal material such as a copper foil film may be used. Further, the conductive film and the first contact 28a and the second contact 30a may be connected via a conductive paint such as silver paste.
  • each piezoelectric film has two protrusions, the first contact 28a is formed on one of the two protrusions 15, and the second contact 30a is formed on the other.
  • the configuration is not limited to this.
  • Each piezoelectric film may have one protruding portion, and the first contact 28a and the second contact 30a may be formed on the one protruding portion 15. Further, in this case, the first contact 28a and the second contact 30a may be formed at overlapping positions in the plane direction, but as shown in FIGS. 13 and 14, different positions may be formed. It is preferably formed in.
  • FIG. 13 is a perspective view conceptually showing another example of the laminated piezoelectric element of the present invention.
  • FIG. 14 is an enlarged exploded view of a part of FIG.
  • the laminated piezoelectric element shown in FIGS. 13 and 14 has a configuration in which five piezoelectric films (12l to 12p) are laminated.
  • the piezoelectric films are laminated so that the polarization directions alternate. That is, in FIG. 14, the first layer piezoelectric film 12l in FIG. 14 is laminated with the first protective layer 28 side facing upward, and the second layer piezoelectric film 12m is on the second protective layer 30 side.
  • the third-layer piezoelectric film 12n is laminated with the first protective layer 28 side facing up, and the fourth-layer piezoelectric film 12o is laminated with the second protective layer 30 side facing up.
  • the fifth layer of the piezoelectric film 12p is laminated with the first protective layer 28 side facing upward.
  • each piezoelectric film has a rectangular adhesive portion and one projecting portion 15 projecting from the long side side of the adhesive portion toward the outside in the plane direction.
  • One protruding portion 15 is provided so as to project from one long side of the bonded portion in a direction away from the bonded portion.
  • the size of the adhesive portion of each piezoelectric film is substantially the same.
  • the first-layer piezoelectric film 12l has a protruding portion 15 formed on one end side on the long side.
  • the protruding portion 15 is formed at a position deviated from the position of the protruding portion 15 of the first layer piezoelectric film 12l toward the other end side.
  • the protruding portion 15 is formed at a position deviated from the position of the protruding portion 15 of the second layer piezoelectric film 12m toward the other end side.
  • the protruding portion 15 is formed at a position deviated from the position of the protruding portion 15 of the third layer piezoelectric film 12n toward the other end side.
  • the protruding portion 15 is formed at a position deviated from the position of the protruding portion 15 of the fourth layer piezoelectric film 12o toward the other end side.
  • the protruding portions of the piezoelectric films have substantially the same size and shape. Further, the protruding portion of each piezoelectric film is formed at a position deviated by one protruding portion from the position of the protruding portion of the adjacent piezoelectric film.
  • a hole 28a penetrating the first protective layer 28 is provided on the root side (adhesive portion side) of the protruding portion 15 of each piezoelectric film, and the hole 28a is provided in the hole 28a. 1
  • the electrode layer 24 is exposed.
  • a hole 30a penetrating the second protective layer 30 is provided on the tip end side of the protruding portion 15 of each piezoelectric film, and the second electrode layer 26 is exposed in the hole 30a. That is, the first contact 28a and the second contact 30a are formed on the front surface and the back surface of the protruding portion 15 of each piezoelectric film, respectively.
  • the protruding portions 15 of the respective piezoelectric films are arranged so as not to overlap each other in the surface direction, as shown in FIG. Will be done.
  • the first contact 28a is formed on the root side of the protruding portion 15 of each piezoelectric film.
  • the first contact 28a is formed on the surfaces opposite to each other in the laminated state. Has been done.
  • a second contact 30a is formed on the tip end side of the protruding portion 15 of each piezoelectric film.
  • the second contact 30a is formed on the surfaces opposite to each other in the laminated state. Has been done.
  • a conductive film 60a is attached from the front surface to the back surface at the position of the first contact 28a on the root side of these five protrusions 15. As a result, the first contact 28a of each piezoelectric film is easily electrically connected.
  • the conductive film 60b is attached from the front surface to the back surface at the position of the second contact 30a on the tip end side of the five protrusions 15. As a result, the second contact 30a of each piezoelectric film is easily electrically connected. At that time, the conductive film connecting the first contact 28a and the conductive film connecting the second contact 30a are arranged so as not to be connected.
  • the piezoelectric films are laminated so that the polarization directions of the piezoelectric layers are alternated.
  • the first contact 28a formed on the protruding portion 15 of the piezoelectric film is on one of the same surfaces. It is formed so as to face the side, and the second contact 30a is formed so as to face the same surface side of the other.
  • FIG. 15 is a perspective view conceptually showing another example of the laminated piezoelectric element of the present invention.
  • the laminated piezoelectric element shown in FIG. 15 has a configuration in which five piezoelectric films are laminated.
  • the piezoelectric films are laminated so that the polarization directions are the same.
  • each piezoelectric film has a rectangular adhesive portion and one projecting portion 15 projecting from the long side side of the adhesive portion toward the outside in the surface direction.
  • One protruding portion 15 is provided so as to project from one long side of the bonded portion in a direction away from the bonded portion.
  • the size of the adhesive portion of each piezoelectric film is substantially the same.
  • each piezoelectric film shown in FIG. 15 is the same as that of the piezoelectric films shown in FIGS. 13 and 14 except that the orientations of the second and fourth layers are different. That is, each piezoelectric film has a protruding portion 15 formed on one end side on the long side.
  • the protruding portion 15 of each piezoelectric film is formed at a position deviated by one protruding portion from the position of the protruding portion 15 of the adjacent piezoelectric film in the length direction of the end side of the adhesive portion where the protruding portion 15 is formed. ing.
  • a hole 28a penetrating the first protective layer 28 is provided on the root side (adhesive part side) of the protruding portion 15 of each piezoelectric film, and the first electrode is provided in the hole 28a. Layer 24 is exposed.
  • a hole 30a penetrating the second protective layer 30 is provided on the tip end side of the protruding portion 15 of each piezoelectric film, and the second electrode layer 26 is exposed in the hole 30a. That is, the first contact 28a and the second contact 30a are formed on the front surface and the back surface of the protruding portion 15 of each piezoelectric film, respectively.
  • the protruding portions 15 of the respective piezoelectric films are arranged so as not to overlap each other in the surface direction, as shown in FIG. Will be done.
  • the first contact 28a is formed on the root side of the protruding portion 15 of each piezoelectric film.
  • a second contact 30a is formed on the tip end side of the protruding portion 15 of each piezoelectric film. As described above, since all the piezoelectric films are laminated in the same direction, in the laminated state, all the second contacts 30a are formed on the surfaces in the same direction.
  • a conductive film is attached to the surface of these five protrusions 15 on the root side where the first contact 28a is formed. As a result, the first contact 28a of each piezoelectric film is easily electrically connected. Similarly, another conductive film is attached to the surface on which the second contact 30a on the tip end side of the five protrusions 15 is formed. As a result, the second contact 30a of each piezoelectric film is easily electrically connected. At that time, the conductive film connecting the first contact 28a and the conductive film connecting the second contact 30a are arranged so as not to be connected.
  • all the protruding portions 15 of the piezoelectric films are arranged at positions where they do not overlap each other in the plane direction, but the present invention is not limited to this.
  • FIG. 16 is a perspective view conceptually showing another example of the laminated piezoelectric element of the present invention.
  • FIG. 17 is an enlarged view of the right side portion of the laminated piezoelectric element shown in FIG.
  • FIG. 18 is a view of FIG. 17 as viewed from the back side.
  • FIG. 19 is an enlarged view of the left side portion of the laminated piezoelectric element shown in FIG.
  • FIG. 20 is a view of FIG. 19 as viewed from the back side.
  • the laminated piezoelectric element shown in FIGS. 16 to 20 has a configuration in which five piezoelectric films are laminated.
  • the piezoelectric films are laminated so that the polarization directions alternate.
  • each piezoelectric film has a rectangular adhesive portion and two projecting portions 15 projecting from the long side side of the adhesive portion toward the outside in the surface direction.
  • the two protrusions 15 are formed on one end side and the other end side of the long side of the adhesive portion, respectively.
  • the size of the adhesive portion of each piezoelectric film is substantially the same.
  • the first contact point is formed on the protrusion 15 formed on the right end face side in FIG. 16, and the protrusion 15 formed on the left end face side in FIG. 16 has a first contact.
  • a second contact is formed.
  • the protrusions 15 formed on the right end surface side in FIG. 16 have the second and third layers, and the fourth and fifth layers at the same positions in the plane direction. It is formed.
  • the first contact formed on the protruding portion 15 of the second layer faces the third layer side
  • the first contact formed on the protruding portion of the third layer faces the second layer side. That is, the first contact point of the second layer and the first contact point of the third layer face each other.
  • the first contact formed on the protrusion 15 of the fourth layer faces the fifth layer side
  • the first contact formed on the protrusion of the fifth layer faces the fourth layer side. ing. That is, the first contact point of the fourth layer and the first contact point of the fifth layer face each other.
  • the first contact formed on the protrusion 15 of the first layer faces the opposite side to the second layer.
  • the first contacts formed on the protrusions 15 in this way are connected to each other by the conductive film 60a.
  • the conductive film 60a covers the first contact point of the protrusion of the first layer, is sandwiched between the second layer and the third layer, and further. It is arranged so as to be sandwiched between the 4th layer and the 5th layer. As a result, the first contacts of the first to fifth layers are connected.
  • the protrusions 15 formed on the left end surface side in FIG. 16 have the same surface directions for the second and third layers, and the fourth and fifth layers. It is formed at the position.
  • the second contact formed on the protrusion 15 of the second layer faces the opposite side to the third layer, and the second contact formed on the protrusion of the third layer is opposite to the second layer. I'm facing the side. That is, a second contact is formed on both sides of the portion where the protruding portions of the second layer and the third layer are laminated.
  • the second contact formed on the protrusion 15 of the fourth layer faces the opposite side to the fifth layer
  • the second contact formed on the protrusion of the fifth layer is the fourth layer. It faces the opposite side. That is, second contacts are formed on both sides of the portion where the protrusions of the fourth layer and the fifth layer are laminated.
  • the second contact formed on the protrusion 15 of the first layer faces the second layer side.
  • the second contacts formed on the protrusions 15 in this way are connected to each other by the conductive film 60b.
  • the conductive film 60b is attached from the front surface side to the back surface side of each protruding portion. As a result, the second contacts of the first to fifth layers are connected.
  • the protrusions of the piezoelectric films are arranged at positions where they do not overlap each other in the plane direction, but the present invention is not limited to this.
  • the projecting portions of the piezoelectric films may project from the same position of the adhesive portion in the surface direction, and the lengths in the projecting directions may be different from each other.
  • FIG. 21 is a perspective view conceptually showing another example of the laminated piezoelectric element of the present invention.
  • FIG. 21 is an exploded view.
  • the laminated piezoelectric element shown in FIG. 21 has a configuration in which five piezoelectric films (12q to 12u) are laminated.
  • the piezoelectric films are laminated so that the polarization directions alternate. That is, in FIG. 21, the first-layer piezoelectric film 12q in FIG. 21 is laminated with the first protective layer 28 side facing upward, and the second-layer piezoelectric film 12r is on the second protective layer 30 side.
  • the third-layer piezoelectric film 12s is laminated with the first protective layer 28 side facing up, and the fourth-layer piezoelectric film 12t is laminated with the second protective layer 30 side facing up.
  • the fifth-layer piezoelectric film 12u is laminated with the first protective layer 28 side facing upward.
  • each piezoelectric film has a rectangular adhesive portion and two projecting portions 15 projecting outward from the short side of the adhesive portion in the plane direction.
  • the two protrusions 15 are provided at one end and the other end of the short side.
  • the size of the adhesive portion of each piezoelectric film is substantially the same.
  • the protruding portion formed at the left end portion in FIG. 21 will be described.
  • the first-layer piezoelectric film 12q has a protruding portion 15 formed at the left end of the short side.
  • the second-layer piezoelectric film 12r is formed with a protruding portion 15 projecting from the same position as the protruding portion 15 of the first-layer piezoelectric film 12q.
  • the protruding portion 15 of the second layer is longer in the protruding direction than the protruding portion 15 of the first layer.
  • the third-layer piezoelectric film 12s is formed with a protruding portion 15 projecting from the same position as the protruding portion 15 of the second-layer piezoelectric film 12r.
  • the protrusion 15 of the third layer has the same length as the protrusion 15 of the second layer.
  • the fourth-layer piezoelectric film 12t is formed with a protruding portion 15 projecting from the same position as the protruding portion 15 of the third-layer piezoelectric film 12s.
  • the protrusion 15 of the fourth layer is longer in the protrusion direction than the protrusion 15 of the third layer.
  • the fifth-layer piezoelectric film 12u is formed with a protruding portion 15 projecting from the same position as the protruding portion 15 of the fourth-layer piezoelectric film 12t.
  • the protrusion 15 of the fifth layer has the same length as the protrusion 15 of the fourth layer.
  • a hole 28a penetrating the first protective layer 28 is provided in the protrusion 15 on the left side in FIG. 21, and the first electrode layer 24 is exposed in the hole 28a. That is, the first contact point 28a is formed on each protruding portion 15.
  • the first, third, and fifth layers of the piezoelectric film and the second, fourth, and fourth layers of the piezoelectric film are laminated in opposite directions. Therefore, as shown in FIG. 21, the first contact point of the second layer and the first contact point of the third layer face each other. Similarly, the first contact point of the fourth layer and the first contact point of the fifth layer face each other.
  • the first contacts formed on the protrusions 15 in this way are connected to each other by a conductive film (not shown).
  • a conductive film that covers the first contact point of the protruding portion of the first layer, a conductive film sandwiched between the protruding portions 15 of the second layer and the third layer, and the fourth and fifth layers.
  • the first-layer piezoelectric film 12q has a protruding portion 15 formed at the right end of the short side.
  • the second-layer piezoelectric film 12r is formed with a protruding portion 15 projecting from the same position as the protruding portion 15 of the first-layer piezoelectric film 12q.
  • the protrusion 15 of the second layer has the same length as the protrusion 15 of the first layer.
  • the third-layer piezoelectric film 12s is formed with a protruding portion 15 projecting from the same position as the protruding portion 15 of the second-layer piezoelectric film 12r.
  • the protrusion 15 of the third layer is longer in the protrusion direction than the protrusion 15 of the second layer.
  • the fourth-layer piezoelectric film 12t is formed with a protruding portion 15 projecting from the same position as the protruding portion 15 of the third-layer piezoelectric film 12s.
  • the protrusion 15 of the fourth layer has the same length as the protrusion 15 of the third layer.
  • the fifth-layer piezoelectric film 12u is formed with a protruding portion 15 projecting from the same position as the protruding portion 15 of the fourth-layer piezoelectric film 12t.
  • the protrusion 15 of the fifth layer has a longer length in the protrusion direction than the protrusion 15 of the fourth layer.
  • the protruding portion 15 on the right side in FIG. 21 is provided with a hole portion 30a penetrating the second protective layer 30, and the second electrode layer 26 is exposed in the hole portion 30a. That is, a second contact 30a is formed on each protruding portion 15.
  • the first, third, and fifth layers of the piezoelectric film and the second, fourth, and fourth layers of the piezoelectric film are laminated in opposite directions. Therefore, as shown in FIG. 21, the second contact point of the first layer and the second contact point of the second layer face each other. Similarly, the second contact point of the third layer and the second contact point of the fourth layer face each other.
  • the second contacts formed on the protrusions 15 in this way are connected to each other by a conductive film (not shown). Specifically, the conductive film sandwiched between the first layer and the second layer, the conductive film sandwiched between the third layer and the fourth layer, and the protruding portion of the fifth layer. By arranging the conductive film covering the second contact and connecting the three conductive films, the second contacts of the first to fifth layers are connected. The arrangement of the conductive film is the same as in the examples of FIGS. 24 to 26 described later.
  • the piezoelectric films are laminated so that the polarization directions alternate, and the protruding portion of each piezoelectric film protrudes from the same position of the bonded portion in the plane direction. Therefore, when the lengths in the protruding directions are different from each other, the contacts of the adjacent piezoelectric films are faced to each other and connected to each other, but the present invention is not limited to this.
  • One protruding portion of the adjacent piezoelectric film may be bent in the protruding direction.
  • FIG. 22 is a partially enlarged perspective view conceptually showing another example of the laminated piezoelectric element of the present invention.
  • FIG. 23 is a cross-sectional view taken along the line BB of FIG.
  • the laminated piezoelectric element shown in FIG. 22 has a configuration in which five piezoelectric films (12q, 12v, 12s, 12w, 12u) are laminated.
  • the piezoelectric films are laminated so that the polarization directions alternate. That is, in FIG. 22, the first-layer piezoelectric film 12q in FIG. 22 is laminated with the first protective layer 28 side facing upward, and the second-layer piezoelectric film 12v is on the second protective layer 30 side.
  • the third-layer piezoelectric film 12s is laminated with the first protective layer 28 side facing up, and the fourth-layer piezoelectric film 12w is laminated with the second protective layer 30 side facing up.
  • the fifth-layer piezoelectric film 12u is laminated with the first protective layer 28 side facing upward.
  • the piezoelectric films of the first, third, and fifth layers have the same configuration as the piezoelectric films of the first, third, and fifth layers of the laminated piezoelectric element shown in FIG. Has a configuration.
  • each piezoelectric film has a rectangular adhesive portion and two projecting portions 15 projecting from the short side side of the adhesive portion toward the outside in the surface direction.
  • the two protrusions 15 are provided at one end and the other end of the short side.
  • the size of the adhesive portion of each piezoelectric film is substantially the same.
  • the protruding portion formed at the left end portion will be described with reference to FIG. 23.
  • the first-layer piezoelectric film 12q has a protruding portion 15 formed at the left end of the short side.
  • the second-layer piezoelectric film 12v is formed with a protruding portion 15 projecting from the same position as the protruding portion 15 of the first-layer piezoelectric film 12q.
  • the protruding portion 15 of the second layer is folded back in the protruding direction. Therefore, the surface of the protruding portion on the first protective layer side of the second layer faces the side of the piezoelectric film 12q of the first layer.
  • the first contact 28a of the second layer is arranged so as to face the piezoelectric film 12q of the first layer.
  • the folded portion of the protruding portion 15 of the second layer is arranged at a position that does not overlap with the protruding portion 15 of the first layer.
  • the third-layer piezoelectric film 12s is formed with a protruding portion 15 projecting from the same position as the protruding portion 15 of the second-layer piezoelectric film 12r.
  • the protrusion 15 of the third layer is longer than the length of the protrusion 15 of the second layer in the folded state.
  • the fourth-layer piezoelectric film 12w is formed with a protruding portion 15 projecting from the same position as the protruding portion 15 of the third-layer piezoelectric film 12s.
  • the protruding portion 15 of the fourth layer is folded back in the protruding direction. Therefore, the surface of the protruding portion on the first protective layer side of the fourth layer faces the side of the piezoelectric film 12q of the first layer. That is, the first contact 28a of the fourth layer is arranged so as to face the piezoelectric film 12q of the first layer.
  • the folded portion of the protruding portion 15 of the fourth layer is arranged at a position that does not overlap with the protruding portion 15 of the third layer.
  • the fifth-layer piezoelectric film 12u is formed with a protruding portion 15 projecting from the same position as the protruding portion 15 of the fourth-layer piezoelectric film 12t.
  • the protrusion 15 of the fifth layer is longer than the length of the protrusion 15 of the fourth layer in the folded state.
  • the adjacent piezoelectric films that is, the protruding portions 15 of the piezoelectric films having one polarization direction, are bent in the protruding direction.
  • the first contact 28a of each piezoelectric film can be arranged on the same surface side. This makes it easier to attach a conductive film or the like to connect the first contact 28a of each piezoelectric film.
  • the second contact point of each piezoelectric film can be arranged on the same surface side with basically the same configuration as described above.
  • the protruding portion 15 formed at the right end portion is provided with a second contact, and the protruding portions 15 of the first, third, and fifth layers of the piezoelectric film are folded back in the protruding direction. Therefore, the second contact 30a of each piezoelectric film can be arranged on the same surface side.
  • the piezoelectric films are laminated so that the polarization directions alternate, but the present invention is not limited to this, and the piezoelectric films have the same polarization direction.
  • the protruding portions of the piezoelectric films may protrude from the same position of the bonding portion in the plane direction, and the lengths in the protruding directions may be different from each other. In this case, the lengths of all the overlapping protrusions are different, and each first contact (or second contact) is formed on the surface of the protrusions facing the same side.
  • the protruding portion of each piezoelectric film protrudes from the same position of the adhesive portion in the surface direction, and the lengths in the protruding direction are different from each other, but the present invention is not limited to this.
  • the projecting portions of the piezoelectric films may project from the same position of the adhesive portion in the surface direction and have the same length in the projecting direction.
  • FIG. 24 is a perspective view conceptually showing another example of the laminated piezoelectric element of the present invention.
  • FIG. 25 is an enlarged view of a portion of the protrusion on the left side of FIG. 24.
  • FIG. 26 is an enlarged view of a portion of the protrusion on the right side of FIG. 24.
  • the laminated piezoelectric element shown in FIG. 24 has a configuration in which five piezoelectric films are laminated. The piezoelectric films are laminated so that the polarization directions alternate.
  • each piezoelectric film has a rectangular adhesive portion and two projecting portions 15 projecting outward from the short side of the adhesive portion in the plane direction.
  • the two protrusions 15 are provided at one end and the other end of the short side.
  • the size of the adhesive portion of each piezoelectric film is substantially the same.
  • a hole 28a penetrating the first protective layer 28 is provided in the protrusion 15 on the left side in FIG. 24, and the first electrode layer 24 is exposed in the hole 28a. That is, the first contact point 28a is formed on each protruding portion 15.
  • the first, third, and fifth layers of the piezoelectric film and the second, fourth, and fourth layers of the piezoelectric film are laminated in opposite directions. Therefore, the first contact point of the second layer and the first contact point of the third layer face each other. Similarly, the first contact point of the fourth layer and the first contact point of the fifth layer face each other.
  • Three conductive films are arranged on these protrusions 15. Specifically, the conductive film 61a covering the first contact point of the first-layer protruding portion 15, the conductive film 61b sandwiched between the second-layer and third-layer protruding portions 15, and the fourth layer.
  • the conductive film 61c sandwiched between the and the fifth layer of the projecting portion 15 is arranged so that the conductive film 61a and the conductive film 61b are brought into contact with each other, and the conductive film 61b and the conductive film 61c are brought into contact with each other. To contact. As a result, the first contacts of the first to fifth layers are connected.
  • the protruding portion 15 on the right side in FIG. 24 is provided with a hole portion 30a penetrating the second protective layer 30, and the second electrode layer 26 is exposed in the hole portion 30a. That is, a second contact 30a is formed on each protruding portion 15.
  • the first, third, and fifth layers of the piezoelectric film and the second, fourth, and fourth layers of the piezoelectric film are laminated in opposite directions. Therefore, the second contact point of the first layer and the second contact point of the second layer face each other. Similarly, the second contact point of the third layer and the second contact point of the fourth layer face each other.
  • Three conductive films are arranged on these protrusions 15. Specifically, the conductive film 61d sandwiched between the protruding portions 15 of the first layer and the second layer, and the conductive film 61e sandwiched between the protruding portions 15 of the third layer and the fourth layer.
  • the conductive film 61f covering the second contact of the fifth layer of the protruding portion 15 is arranged so that the conductive film 61d and the conductive film 61e are brought into contact with each other, and the conductive film 61e and the conductive film 61f are brought into contact with each other. To make contact with. As a result, the second contacts of the first to fifth layers are connected.
  • the protruding portion of each piezoelectric film is formed on a part of the width direction of the end side of the adhesive portion on which the protruding portion is formed, that is, the protruding portion.
  • the width in the direction orthogonal to the protruding direction of the above is shorter than the width of the end edge of the adhesive portion on which the protruding portion is formed, but the width is not limited to this.
  • the width of the protruding portion of each piezoelectric film in the direction orthogonal to the protruding direction may be the same as the width of the end edge of the adhesive portion on which the protruding portion is formed.
  • FIG. 27 is a partially enlarged perspective view conceptually showing another example of the laminated piezoelectric element of the present invention.
  • the laminated piezoelectric element shown in FIG. 27 has a configuration in which five piezoelectric films are laminated.
  • the piezoelectric films are laminated so that the polarization directions alternate.
  • each piezoelectric film has a rectangular adhesive portion and one projecting portion 15 projecting outward from the short side of the adhesive portion in the plane direction.
  • the protrusion 15 has the same width as the width of the short side.
  • a hole 28a (first contact 28a) penetrating the first protective layer 28 is formed at the left end of the protrusion 15.
  • the first, third, and fifth layers of the piezoelectric film and the second, fourth, and fourth layers of the piezoelectric film are laminated in opposite directions. Therefore, the first contact point of the second layer and the first contact point of the third layer face each other. Similarly, the first contact point of the fourth layer and the first contact point of the fifth layer face each other.
  • Three conductive films (61a, 61b, 61c) are arranged at the positions of these first contacts 28a.
  • the arrangement of the three conductive films (61a, 61b, 61c) is the same as in FIG. 25. That is, the conductive film 61a covering the first contact 28a of the first layer piezoelectric film, the conductive film 61b sandwiched between the second layer and the third layer and connected to each first contact 28a, and 4 It has a conductive film 61c sandwiched between the first layer and the fifth layer and connected to each first contact 28a, and by bringing three conductive films (61a, 61b, 61c) into contact with each other, 1 The first contacts of the first to fifth layers are connected.
  • a hole portion 30a (second contact point 30a) penetrating the second protective layer 30 is formed at the right end portion of the protruding portion 15.
  • the first, third, and fifth layers of the piezoelectric film and the second, fourth, and fourth layers of the piezoelectric film are laminated in opposite directions. Therefore, the second contact point of the first layer and the second contact point of the second layer face each other. Similarly, the second contact point of the third layer and the second contact point of the fourth layer face each other.
  • Three conductive films (61d, 61e, 61f) are arranged at the positions of these second contacts 30a.
  • the arrangement of the three conductive films (61d, 61e, 61f) is the same as in FIG. 26. That is, the conductive film 61d sandwiched between the first layer and the second layer and connected to each second contact 30a, and sandwiched between the third layer and the fourth layer and connected to each second contact 30a.
  • the conductive film 61e to be formed and the conductive film 61f covering the second contact 30a of the fifth layer piezoelectric film are provided, and the three conductive films (61d, 61e, 61f) are brought into contact with each other.
  • the second contacts of the first to fifth layers are connected.
  • the corner portion of the connecting portion between the protruding portion and the adhesive portion is formed.
  • R structure is provided. R is preferably 0.3 mm or more, more preferably 0.5 mm or more. Since each electric film is thin, the protrusions that are not laminated hang down from the root. This can be suppressed by providing an R structure at the corner of the connecting portion between the protruding portion and the adhesive portion.
  • this R structure indicates that at the intersection of the straight line forming the protruding portion and the straight line forming the adhesive portion, there is a portion where the shape of the ridge line of the protruding portion changes within the above radius regulation, and it is not necessarily R.
  • the structure does not have to be a circle. That is, the connecting portion between the protruding portion and the adhesive portion may have a region in which the protruding portion gradually widens from the tip end side toward the root portion. More specifically, the ridgeline of the protrusion and the ridgeline of the adhesive portion are applied to the coordinates.
  • a tangent R0.5 on the coordinate axis made by extending the straight line of the part separated by 5 mm or more from the connection part between the protruding part and the adhesive part, and define the tangent R0.5 and the area A surrounded by the coordinate axes.
  • the area B surrounded by the ridgeline and the coordinate axes of the wide area formed in the actual protrusion is larger than the area A.
  • the width of the protruding portion in the direction orthogonal to the protruding direction is preferably narrower on the tip side than on the adhesive portion side (root side), and is separated from the adhesive portion. It is preferable that the amount gradually narrows as the amount increases. Further, as a specific shape of the protruding portion, it is preferable that the protruding portion has a trapezoidal shape when viewed from a direction perpendicular to the main surface of the bonded portion (hereinafter, also referred to as “in a plan view”). This point will be described with reference to FIGS. 54 to 57.
  • FIG. 54 is a conceptual diagram showing an example of a laminated piezoelectric element having a rectangular protruding portion.
  • FIG. 55 is an enlarged view showing a part of the laminated piezoelectric element of FIG. 54.
  • FIG. 56 is a conceptual diagram showing an example of a laminated piezoelectric element having a trapezoidal protruding portion.
  • FIG. 57 is an enlarged view showing a part of the laminated piezoelectric element of FIG. 56.
  • each of the five piezoelectric films 12 has a protruding portion 15 on the side that becomes the same side when laminated.
  • the protrusions 15 of the piezoelectric films 12 are formed at positions shifted in the direction along the side on which the protrusions 15 are formed so as not to overlap when viewed from a direction perpendicular to the main surface.
  • the protruding portion 15 of the laminated piezoelectric element shown in FIG. 54 has the same width in the direction orthogonal to the protruding direction on the adhesive portion side (root side) and the tip side. That is, the shape of the protruding portion in a plan view is rectangular.
  • each protrusion 15 is formed at a close position. That is, it is preferable that the distance between the protruding portions 15 in the plane direction is narrow.
  • the piezoelectric film 12, that is, the protruding portion 15 is very thin, the protruding portion 15 is easily bent. Therefore, when the shape of the protrusions is rectangular, if the distance between the protrusions 15 is narrow, the side surfaces of the protrusions 15 are likely to come into contact with each other when the protrusions 15 are bent, and one of the protrusions 15 is likely to come into contact with each other.
  • the first electrode layer of the above and the second electrode layer of the other protruding portion 15 may come into contact with each other to cause a short circuit.
  • the excessive cutting portion 15a may interfere with the adjacent piezoelectric film 12 to cause a short circuit.
  • the laminated piezoelectric element shown in FIG. 56 has a protruding portion 15 on the side side which is the same side when the five piezoelectric films 12 are laminated.
  • the protrusions 15 of the piezoelectric films 12 are formed at positions shifted in the direction along the side on which the protrusions 15 are formed so as not to overlap when viewed from a direction perpendicular to the main surface.
  • the width of the protruding portion 15 of the laminated piezoelectric element shown in FIG. 56 in the direction orthogonal to the protruding direction is narrower on the tip side than on the bonding portion side (root side).
  • the shape of the protruding portion in the plan view is trapezoidal.
  • the width of the protruding portion 15 is narrow on the tip side, it becomes difficult for the side surfaces of the protruding portion 15 to come into contact with each other even when the protruding portion 15 is bent. Therefore, it is possible to prevent a short circuit from occurring even if the distance between the protruding portions 15 is narrowed. Further, since the width of the root portion of the protruding portion 15 is large, it is possible to suppress an increase in the current density of the current flowing through the protruding portion 15, and it is possible to suppress heat generation.
  • the shape of the protruding portion 15 is trapezoidal, as shown in FIG. 57, excessive cutting is unlikely to occur when the piezoelectric film is cut to form the protruding portion 15. Therefore, even if pressure is applied when laminating the piezoelectric films, it is possible to prevent the excessively cut portion from interfering with the adjacent piezoelectric film 12 and causing a short circuit.
  • the shape of the protruding portion is trapezoidal, but the shape is not limited to this, and the width on the tip side may be narrower than the width on the root side.
  • the side of the protruding portion in contact with the adhesive portion may be curved.
  • the width of the protruding portion may be gradually narrowed from the root side to the tip side (stepped shape).
  • each piezoelectric film has a single-layered single-wafer shape, but the present invention is not limited to this. At least one of the plurality of piezoelectric films may have a bellows shape that is folded back at least once.
  • FIG. 28 An example of a bellows-shaped piezoelectric film is shown in FIG.
  • the piezoelectric film shown in FIG. 28 is obtained by laminating a plurality of layers of a piezoelectric film by folding the piezoelectric film a plurality of times. Further, as a preferred embodiment, each layer of the piezoelectric film laminated by folding back is attached by an adhesive layer. By folding back and laminating one piece of piezoelectric film polarized in the thickness direction, the polarization direction of the piezoelectric film adjacent (facing) in the laminating direction becomes opposite.
  • the electrode may be pulled out from the piezoelectric film at one place. Therefore, by making the laminated piezoelectric element a lattice having a bellows-shaped piezoelectric film, the number of parts is reduced, the configuration is simplified, the reliability as a piezoelectric element (module) is improved, and the cost is further increased. It can be downed.
  • the number of times of folding is set to an even number, and an odd number of layers are laminated so that the first protective layer 28 is on one surface.
  • the second protective layer 30 becomes the surface. Therefore, the electrode can be easily pulled out by forming the first contact 28a on the surface of the first protective layer 28 side and forming the second contact 30a on the surface of the second protective layer 30 side.
  • FIGS. 29 to 36 Examples of laminated piezoelectric elements including one or more such bellows-shaped piezoelectric films are shown in FIGS. 29 to 36.
  • Each of the laminated piezoelectric elements shown in FIGS. 29 to 32 has a structure in which a bellows-shaped piezoelectric film 12L and a single-wafer-shaped piezoelectric film 12 are laminated.
  • the bellows-shaped piezoelectric film 12L has a protruding portion 15 that is not adhered to the single-wafer-shaped piezoelectric film 12, and a first contact and a second contact (not shown) are formed in the protruding portion 15.
  • a conductive film 62a is connected to the first contact. Further, a conductive film 62b is connected to the second contact.
  • the single-wafer-shaped piezoelectric film 12 has a protruding portion 15 that is not adhered to the bellows-shaped piezoelectric film 12L, and a first contact and a second contact (not shown) are formed in the protruding portion 15.
  • a conductive film 62c is connected to the first contact.
  • a conductive film 62d is connected to the second contact.
  • the polarization direction of the single-wafer-shaped piezoelectric film 12 and the polarization direction of the bellows-shaped piezoelectric film 12L in the layer in contact with the single-wafer-shaped piezoelectric film 12 are the same. Further, the protruding portion 15 of the single-wafer-shaped piezoelectric film 12 and the protruding portion 15 of the bellows-shaped piezoelectric film 12L are formed at different positions in the surface direction.
  • the polarization direction of the single-wafer-shaped piezoelectric film 12 is opposite to the polarization direction of the bellows-shaped piezoelectric film 12L in the layer in contact with the single-wafer-shaped piezoelectric film 12. Further, the protruding portion 15 of the single-wafer-shaped piezoelectric film 12 and the protruding portion 15 of the bellows-shaped piezoelectric film 12L are formed at different positions in the surface direction.
  • the polarization direction of the single-wafer-shaped piezoelectric film 12 and the polarization direction of the bellows-shaped piezoelectric film 12L in the layer in contact with the single-wafer-shaped piezoelectric film 12 are the same. Further, the protruding portion 15 of the single-wafer-shaped piezoelectric film 12 and the protruding portion 15 of the bellows-shaped piezoelectric film 12L are formed at the same positions in the surface direction.
  • the polarization direction of the single-wafer-shaped piezoelectric film 12 is opposite to the polarization direction of the bellows-shaped piezoelectric film 12L in the layer in contact with the single-wafer-shaped piezoelectric film 12. Further, the protruding portion 15 of the single-wafer-shaped piezoelectric film 12 and the protruding portion 15 of the bellows-shaped piezoelectric film 12L are formed at the same positions in the surface direction.
  • Each of the laminated piezoelectric elements shown in FIGS. 33 to 36 has a configuration in which two bellows-shaped piezoelectric films are laminated.
  • the bellows-shaped piezoelectric film 12La has a protruding portion 15 that is not adhered to the bellows-shaped piezoelectric film 12Lb, and a first contact and a second contact (not shown) are formed in the protruding portion 15.
  • a conductive film 62a is connected to the first contact. Further, a conductive film 62b is connected to the second contact.
  • the bellows-shaped piezoelectric film 12Lb has a protruding portion 15 that is not adhered to the bellows-shaped piezoelectric film 12La, and a first contact and a second contact (not shown) are formed in the protruding portion 15.
  • a conductive film 62e is connected to the first contact.
  • a conductive film 62f is connected to the second contact.
  • the polarization direction of the bellows-shaped piezoelectric film 12La in the layer in contact with the bellows-shaped piezoelectric film 12Lb and the polarization direction of the bellows-shaped piezoelectric film 12Lb in the layer in contact with the bellows-shaped piezoelectric film 12La. are opposite to each other.
  • the protruding portions 15 of the two bellows-shaped piezoelectric films are formed at the same positions in the surface direction.
  • the protruding portion 15 of the bellows-shaped piezoelectric film 12La is formed on a layer on the side not in contact with the bellows-shaped piezoelectric film 12Lb.
  • the protruding portion 15 of the bellows-shaped piezoelectric film 12Lb is formed on the layer on the side in contact with the bellows-shaped piezoelectric film 12La.
  • the polarization direction of the bellows-shaped piezoelectric film 12La in the layer in contact with the bellows-shaped piezoelectric film 12Lb and the polarization direction of the bellows-shaped piezoelectric film 12Lb in the layer in contact with the bellows-shaped piezoelectric film 12La. are opposite to each other.
  • the protruding portions 15 of the two bellows-shaped piezoelectric films are formed at the same positions in the surface direction.
  • the protruding portion 15 of the bellows-shaped piezoelectric film 12La is formed on a layer on the side not in contact with the bellows-shaped piezoelectric film 12Lb.
  • the protruding portion 15 of the bellows-shaped piezoelectric film 12Lb is formed in a layer on the side not in contact with the bellows-shaped piezoelectric film 12La.
  • the polarization direction of the bellows-shaped piezoelectric film 12La in the layer in contact with the bellows-shaped piezoelectric film 12Lb and the polarization direction of the bellows-shaped piezoelectric film 12Lb in the layer in contact with the bellows-shaped piezoelectric film 12La. are opposite to each other.
  • the protruding portions 15 of the two bellows-shaped piezoelectric films are formed at different positions in the surface direction.
  • the protruding portion 15 of the bellows-shaped piezoelectric film 12La is formed on a layer on the side not in contact with the bellows-shaped piezoelectric film 12Lb.
  • the protruding portion 15 of the bellows-shaped piezoelectric film 12Lb is formed on the layer on the side in contact with the bellows-shaped piezoelectric film 12La.
  • the polarization direction of the bellows-shaped piezoelectric film 12La in the layer in contact with the bellows-shaped piezoelectric film 12Lb and the polarization direction of the bellows-shaped piezoelectric film 12Lb in the layer in contact with the bellows-shaped piezoelectric film 12La. are opposite to each other.
  • the protruding portions 15 of the two bellows-shaped piezoelectric films are formed at different positions in the surface direction.
  • the protruding portion 15 of the bellows-shaped piezoelectric film 12La is formed on a layer on the side not in contact with the bellows-shaped piezoelectric film 12Lb.
  • the protruding portion 15 of the bellows-shaped piezoelectric film 12Lb is formed in a layer on the side not in contact with the bellows-shaped piezoelectric film 12La.
  • the layer structure of each piezoelectric film, the formation position of the protruding portion, and the like can be various.
  • the protruding portion 15 has a configuration in which the first protective layer 28, the first electrode layer 24, the piezoelectric layer 20, the second electrode layer 26, and the second protective layer 30 are laminated. That is, the protruding portion 15 has the same layer structure as that of the piezoelectric film 12, but is not limited thereto.
  • the protruding portion may have a structure in which at least the first electrode layer 24 and the first protective layer 28, or the second electrode layer 26 and the second protective layer 30 are laminated.
  • FIG. 37 is a diagram conceptually showing another example of the laminated piezoelectric element of the present invention.
  • FIG. 38 is a top view of FIG. 38.
  • FIG. 39 is a side view of FIG. 38.
  • FIG. 40 is a diagram showing each of a plurality of piezoelectric films included in the laminated piezoelectric element of FIG. 37.
  • FIGS. 37 to 39 have a configuration in which three piezoelectric films are laminated.
  • the piezoelectric films are laminated so that the polarization directions are the same.
  • the first-layer piezoelectric film 72a in FIG. 37 is laminated with the first protective layer 28 side facing upward
  • the second-layer piezoelectric film 72b is the first protective layer 28.
  • the third layer of the piezoelectric film 72c is laminated with the side facing up
  • the first protective layer 28 is laminated with the side facing up.
  • each piezoelectric film has a rectangular adhesive portion 73 and two protrusions 75a and 75b protruding outward in the surface direction from the long side side of the adhesive portion 73.
  • the protruding portion 75a has a structure in which the first protective layer 28 and the first electrode layer 24 are laminated.
  • the projecting portion 75a is provided so as to project outward from one long side of the adhesive portion 73.
  • the protruding portion 75b has a structure in which the second protective layer 30 and the second electrode layer 26 are laminated.
  • the projecting portion 75b is provided so as to project outward from the other long side of the adhesive portion 73.
  • the size of the adhesive portion 13 of each piezoelectric film is substantially the same.
  • each piezoelectric film has a long side on which a protruding portion 75a composed of a first protective layer 28 and a first electrode layer 24 is arranged, and a protruding portion 75b composed of a second protective layer 30 and a second electrode layer 26.
  • the long sides to be formed are laminated so as to coincide with each other in the plane direction.
  • the first layer piezoelectric film 72a is formed with a protrusion 75a on one end side of one long side of the adhesive portion 73, and is formed on one end side of the other long side.
  • a protruding portion 75b is formed.
  • the protrusions 75a and 75b are formed at positions deviated from the positions of the protrusions of the first-layer piezoelectric film 72a toward the other end, respectively.
  • the third-layer piezoelectric film 72c is formed with protrusions 75a and 75b at positions deviated from the positions of the protrusions of the second-layer piezoelectric film 72b toward the other end, respectively.
  • FIG. 40 the first layer piezoelectric film 72a is formed with a protrusion 75a on one end side of one long side of the adhesive portion 73, and is formed on one end side of the other long side.
  • a protruding portion 75b is formed.
  • the protrusions 75a and 75b are formed at positions deviated from the positions
  • the protruding portions of the piezoelectric films have substantially the same size and shape. Further, the protruding portion of each piezoelectric film is formed at a position deviated by one protruding portion from the position of the protruding portion of the adjacent piezoelectric film.
  • the first electrode layer 24 is exposed on the surface on the middle side in the drawing. Further, the second electrode layer 26 is exposed at the protruding portion 75b on the other long side of each piezoelectric film. That is, the exposed first electrode layer 24 of the protruding portion 75a formed on one long side of each piezoelectric film serves as the first contact point, and the exposed second electrode layer 26 of the protruding portion 75b formed on the other long side serves as the first contact point. Is the second contact point.
  • first contact point is formed on each of the protruding portions 75a on the long side of one of the piezoelectric films.
  • the conductive film 63a is attached to the surface of these protruding portions 75a on the side of the first contact point (first electrode layer 24). As a result, the first contact of each piezoelectric film is easily electrically connected.
  • a second contact (second electrode layer 26) is formed on each of the protruding portions 75b on the other long side of each piezoelectric film.
  • the conductive film 63b is attached to the surface of these protruding portions 75b on the side of the second contact point (second electrode layer 26). As a result, the second contact of each piezoelectric film is easily electrically connected.
  • the protruding portion has a structure in which at least the first electrode layer 24 and the first protective layer 28, or the second electrode layer 26 and the second protective layer 30 are laminated, the adjacent piezoelectric films are formed.
  • the first electrode layers 24 and the second electrode layers 26 can be easily connected to each other. ..
  • the protruding portions of the piezoelectric films are arranged so as not to overlap in the plane direction, but the present invention is not limited to this, and as shown in FIG. 42, adjacent piezoelectric films are provided.
  • the protrusions of the film may be arranged so as to partially overlap in the plane direction.
  • the piezoelectric films are laminated so as to have the same polarization direction, but the present invention is not limited to this, and each piezoelectric film has alternating polarization directions. It may be laminated on.
  • the protruding portions 75a of the adjacent piezoelectric films or the protruding portions 75b may be formed at the same position in the plane direction.
  • the protruding portion has a structure in which at least the first electrode layer 24 and the first protective layer 28, or the second electrode layer 26 and the second protective layer 30 are laminated
  • the above-mentioned FIG. 21 shows.
  • the protruding portions 75a and / or the protruding portions 75b of the piezoelectric film may each protrude from the same position of the adhesive portion in the surface direction, and the lengths in the protruding directions may be different from each other.
  • the protruding portion 75a and / or the protruding portions 75b of the piezoelectric films project from the same position of the bonded portion in the plane direction, respectively.
  • the protruding portion may be bent in the protruding direction so that the first contact or the second contact of each piezoelectric film is arranged on the same surface side.
  • the protruding portion 75a and / or the protruding portion 75b of each piezoelectric film protrudes from the same position of the adhesive portion in the surface direction, and the length in the protruding direction is the same. It may be configured to be connected by using a plurality of conductive films.
  • At least one piezoelectric film is a bellows-shaped piezoelectric film
  • the bellows-shaped piezoelectric film is a protruding portion 75a composed of a first protective layer 28 and a first electrode layer 24, and a second protective layer 30 and a first. It may be configured to have a protruding portion 75b composed of two electrode layers 26.
  • the protruding portion may have a structure in which the first protective layer 28, the first electrode layer 24, the piezoelectric layer 20, the second electrode layer 26, and the second protective layer 30 are laminated. The same is true.
  • the present invention is not limited to the above-mentioned examples, and various improvements and changes are made without departing from the gist of the present invention. Of course, it is also good.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Multimedia (AREA)
  • Piezo-Electric Transducers For Audible Bands (AREA)
  • Diaphragms For Electromechanical Transducers (AREA)
PCT/JP2021/007901 2020-03-19 2021-03-02 積層圧電素子および電気音響変換器 Ceased WO2021187086A1 (ja)

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JP2022508187A JP7457790B2 (ja) 2020-03-19 2021-03-02 積層圧電素子および電気音響変換器
CN202180019823.7A CN115244720A (zh) 2020-03-19 2021-03-02 层叠压电元件及电声换能器
KR1020227031142A KR20220140576A (ko) 2020-03-19 2021-03-02 적층 압전 소자 및 전기 음향 변환기
EP21771776.8A EP4124066A4 (en) 2020-03-19 2021-03-02 LAMINATED PIEZOELECTRIC ELEMENT AND ELECTROACOUSTIC TRANSDUCER
US17/946,825 US12075211B2 (en) 2020-03-19 2022-09-16 Laminated piezoelectric element and electroacoustic transducer

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JP2020-049274 2020-03-19
JP2020-212292 2020-12-22
JP2020212292 2020-12-22

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US20240107889A1 (en) * 2022-09-22 2024-03-28 National Taiwan University Piezoelectric material composite membrane acoustic component with broadband and high sound quality and manufacturing method thereof

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CN117729500B (zh) * 2024-02-08 2024-04-30 成都纤声科技有限公司 一种声学压电结构、声学传感器和电子设备

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JP7457790B2 (ja) 2024-03-28
EP4124066A1 (en) 2023-01-25
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KR20220140576A (ko) 2022-10-18
US20230019706A1 (en) 2023-01-19
TW202137783A (zh) 2021-10-01
EP4124066A4 (en) 2023-09-06
CN115244720A (zh) 2022-10-25

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