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WO2017030045A1 - Film de conversion électroacoustique, procédé de fabrication d'un film de conversion électroacoustique et transducteur électroacoustique - Google Patents

Film de conversion électroacoustique, procédé de fabrication d'un film de conversion électroacoustique et transducteur électroacoustique Download PDF

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Publication number
WO2017030045A1
WO2017030045A1 PCT/JP2016/073413 JP2016073413W WO2017030045A1 WO 2017030045 A1 WO2017030045 A1 WO 2017030045A1 JP 2016073413 W JP2016073413 W JP 2016073413W WO 2017030045 A1 WO2017030045 A1 WO 2017030045A1
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WIPO (PCT)
Prior art keywords
conversion film
electroacoustic
electroacoustic conversion
electrode
layer
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PCT/JP2016/073413
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English (en)
Japanese (ja)
Inventor
信 小澤
高見 新川
井上　大輔
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富士フイルム株式会社
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Priority to JP2017535496A priority Critical patent/JP6450014B2/ja
Publication of WO2017030045A1 publication Critical patent/WO2017030045A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R17/00—Piezoelectric transducers; Electrostrictive transducers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R31/00—Apparatus or processes specially adapted for the manufacture of transducers or diaphragms therefor
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R7/00—Diaphragms for electromechanical transducers; Cones
    • H04R7/02—Diaphragms for electromechanical transducers; Cones characterised by the construction
    • H04R7/12—Non-planar diaphragms or cones
    • 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
    • H10N30/08—Shaping or machining of piezoelectric or electrostrictive bodies
    • H10N30/084—Shaping or machining of piezoelectric or electrostrictive bodies by moulding or extrusion
    • 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
    • H10N30/09—Forming piezoelectric or electrostrictive materials
    • H10N30/092—Forming composite materials
    • 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

Definitions

  • the present invention relates to an electroacoustic conversion film used for an acoustic device such as a speaker, a manufacturing method thereof, and an electroacoustic transducer.
  • the speakers used in these thin displays are also required to be lighter and thinner.
  • the shape of a conventional speaker is generally a funnel-shaped so-called cone type or a spherical dome shape.
  • the speaker cannot be sufficiently thinned, and the lightness may be impaired.
  • carrying and the like are troublesome.
  • a piezoelectric film having a sheet-like flexibility and a property of expanding and contracting in response to an applied voltage is used. It has been proposed.
  • An electroacoustic conversion film disclosed in Patent Document 1 includes a polymer composite piezoelectric material (piezoelectric layer) in which piezoelectric particles are dispersed in a viscoelastic matrix made of a polymer material having viscoelasticity at room temperature, It has a thin film electrode formed on both surfaces of the molecular composite piezoelectric material and a protective layer formed on the surface of the thin film electrode.
  • such an electroacoustic conversion film converts vibration (sound) and an electric signal by the conversion film itself expanding and contracting in a surface direction and vibrating in a direction perpendicular to the surface in response to an applied voltage. To do. At that time, in order to convert the expansion and contraction in the surface direction of the conversion film into vibration in a direction perpendicular to the surface, it is necessary to hold the conversion film in a curved state. Therefore, in Patent Document 1, it is described that the viscoelastic support is pressed against the back surface of the conversion film, or the conversion film is curved and supported by applying air pressure in a case sealed with the conversion film. Yes.
  • Patent Document 2 describes that a piezoelectric film using PVDF (Poly Vinylidene DiFluoride) as a piezoelectric layer is heat-pressed into a dome shape to bend the conversion film.
  • PVDF Poly Vinylidene DiFluoride
  • An object of the invention is to solve such problems of the prior art, and an electroacoustic conversion film and an electroacoustic conversion that can be reproduced at a sufficient volume, have high heat dissipation, and have little change in sound pressure over time. It is in providing the manufacturing method and electroacoustic transducer of a film.
  • a polymer composite piezoelectric material in which piezoelectric particles are dispersed in a viscoelastic matrix made of a polymer material having viscoelasticity at room temperature, and a polymer Two thin-film electrodes laminated on both surfaces of the composite piezoelectric material and two protective layers laminated on the two thin-film electrodes, respectively, are laminated so as to protrude toward one main surface side.
  • this invention provides the electroacoustic conversion film of the following structures, the manufacturing method of an electroacoustic conversion film, and an electroacoustic transducer.
  • a polymer composite piezoelectric material obtained by dispersing piezoelectric particles in a viscoelastic matrix made of a polymer material having viscoelasticity at room temperature;
  • An electroacoustic conversion film in which the ratio H / Ds between the molding height H of the convex portion and the short axis Ds of the convex portion when viewed from a direction perpendicular to the main surface satisfies 0 ⁇ H / Ds ⁇ 0.15.
  • the electroacoustic conversion film according to (1) wherein the shape of the convex portion is a part of a sphere or a part of a spheroid.
  • the protective layer has a hole that penetrates to the electrode layer, The electroacoustic conversion film as described in (1) or (2) which has an electrode extraction part electrically connected to an electrode layer through a hole.
  • the electroacoustic conversion film as described in (3) which has 3 or more electrode extraction parts connected to an electrode layer through the hole of a protective layer.
  • the support member has a through hole having the same shape as the shape of the convex portion when viewed from a direction perpendicular to the main surface of the electroacoustic conversion film, The electroacoustic transducer according to (6), wherein the edge portion of the convex portion of the electroacoustic conversion film is sandwiched between the two support members.
  • an electroacoustic conversion film that can be reproduced at a sufficient volume, has high heat dissipation, and has a small change in sound pressure over time, a method for producing an electroacoustic conversion film, and an electroacoustic transducer are provided. can do.
  • FIG. 2 is a cross-sectional view taken along the line II-II of the electroacoustic conversion film shown in FIG. It is the top view which looked at FIG. 2A from b direction. It is a top view which shows typically another example of the electroacoustic conversion film of this invention. It is sectional drawing which shows typically another example of the electroacoustic conversion film of this invention. It is sectional drawing which shows typically an example of the layer structure of an electrical sound table conversion film. It is sectional drawing which shows typically an example of the layer structure of an electrical sound table conversion film. It is sectional drawing which shows notionally an example of the electroacoustic transducer of this invention.
  • the electroacoustic conversion film of the present invention is used as a diaphragm of an electroacoustic transducer.
  • the electroacoustic conversion film expands in the in-plane direction by applying a voltage to the electroacoustic conversion film, the electroacoustic conversion film absorbs the extension, and the electroacoustic conversion film moves upward (radiation direction of sound).
  • the electroacoustic conversion film contracts in the in-plane direction by applying a voltage to the electroacoustic conversion film, the electroacoustic conversion film moves downward to absorb this contraction.
  • the electroacoustic transducer converts vibration (sound) and an electric signal by vibration caused by repeated expansion and contraction of the electroacoustic conversion film.
  • Such electroacoustic transducers are used as various acoustic devices such as full-range speakers, tweeters, squawkers, woofers, speakers, headphones, earphone speakers, noise cancellers, microphones, and pickups used in musical instruments such as guitars. It is used to input an electric signal to the electroacoustic conversion film and reproduce the sound by vibration according to the electric signal, or to convert the vibration of the electroacoustic conversion film by receiving the sound wave into an electric signal. It is what is done.
  • FIG. 1 is a perspective view schematically showing an example of the electroacoustic conversion film of the present invention
  • FIG. 2A is a cross-sectional view taken along the line II-II of the electroacoustic conversion film of FIG. 1
  • FIG. 4A is a cross-sectional view schematically showing the layer configuration of the electroacoustic conversion film.
  • an electroacoustic conversion film (hereinafter also referred to as a conversion film) 10 of the present invention is laminated on a piezoelectric layer 12 that is a piezoelectric sheet-like material and one surface of the piezoelectric layer 12.
  • It is a film-like laminate having a layer structure laminated with the upper protective layer 20, and as shown in FIGS. 1, 2A and 2B, a convex portion 10a molded at the center of the film-like laminate is provided.
  • the ratio H between the molding height H of the convex portion 10a hereinafter also simply referred to as height H
  • the short diameter Ds of the convex portion 10a when viewed from the direction perpendicular to the main surface of the conversion film 10 / Ds satisfies 0 ⁇ H / Ds ⁇ 0.15.
  • the conversion film 10 has a configuration in which both surfaces of the piezoelectric layer 12 are sandwiched between electrode pairs, that is, the upper thin film electrode 16 and the lower thin film electrode 14, and are further sandwiched between the upper protective layer 20 and the lower protective layer 18. It has a configuration in which a convex portion 10a having a predetermined shape is molded in the laminate. The region of the piezoelectric layer 12 held by the upper thin film electrode 16 and the lower thin film electrode 14 is driven according to the applied voltage and expands and contracts in the surface direction. At that time, in the region of the convex portion 10a, the expansion and contraction in the surface direction is converted into vibration in a direction perpendicular to the surface, and vibration (sound) and an electric signal are converted.
  • the conversion film 10 has a square shape, and a convex portion 10 a having a diameter Ds, a height H, and a shape of a part of a sphere is formed at the center thereof. Moreover, the convex part 10a is formed in concave shape, when it sees from the surface on the opposite side to the surface of the side from which the convex part 10a protrudes. That is, it can also be said that the conversion film 10 is obtained by molding a recess.
  • the viscoelastic support is deformed over time, and the amount of bending of the conversion film is increased. Since it changes, there is a risk that the sound pressure and sound quality will change. Moreover, since heat dissipation becomes worse and the temperature of the conversion film rises during continuous use, it may lead to discomfort when used as headphones. In addition, in the configuration where the conversion film is bent by applying air pressure to the case sealed with the conversion film, the pressure in the case changes over time and the amount of bending of the conversion film changes, so the sound pressure and sound quality change. There is a risk that.
  • the convex portion 10a on the conversion film 10 by forming the convex portion 10a on the conversion film 10 in this way, the expansion and contraction in the surface direction of the conversion film is applied to the vibration in the direction perpendicular to the surface when a voltage is applied.
  • a curved state can be created for conversion. Therefore, a member such as an elastic support for bending the conversion film 10 and a mechanism for applying air pressure become unnecessary. Therefore, the bending amount of the conversion film does not change with time, and the sound pressure and sound quality can be prevented from changing.
  • it can be set as the structure which open
  • an elastic support for curving the conversion film 10 or a structure for applying air pressure is not necessary, the conversion film 10 can be reduced in size and thickness.
  • the ratio H / Ds between the molding height H of the convex portion and the short axis Ds of the convex portion when viewed from the direction perpendicular to the main surface is 0 ⁇ H / Ds ⁇
  • the shape of the convex portion is not particularly limited, but the shape of the convex portion is preferably a part of a sphere or a part of a spheroid, from a direction perpendicular to the main surface of the conversion film.
  • the shape of the convex portion when viewed is not particularly limited, but is preferably a substantially circular shape as shown in FIG. 2B or a substantially elliptical shape as shown in FIG. 3A.
  • the shape of the convex portion when viewed in a cross section perpendicular to the main surface of the conversion film is preferably curved as a whole as shown in FIG. 2A, but the top portion is flat as shown in FIG. 3B. It may be molded.
  • a convex portion having a part of a sphere or a part of a spheroid is also referred to as a dome shape.
  • the ratio H / Ds between the height H of the convex portion and the minor axis Ds of the convex portion is greater than 0 and 0.15 or less, and the upper limit value is 0.1 or less in that the sound pressure can be further improved.
  • the upper limit value is 0.1 or less in that the sound pressure can be further improved.
  • it is 0.075 or less, more preferably 0.05 or less, and the lower limit is preferably 0.003 or more, and is 0.005 or more. Is more preferable.
  • the minor axis Ds of the convex part is a diameter when the convex part has a circular shape when viewed from a direction perpendicular to the main surface of the conversion film, and a minor axis when the convex part has an elliptical shape. Yes, in the case of a square shape, it is the length of the short side.
  • the width of the marginal portion is not particularly limited.
  • the width is preferably such that the edge portion can be suitably held by the support member, preferably 1 mm to 30 mm or less, and more preferably 5 mm to 20 mm.
  • the layer structure of the conversion film 10 is laminated on the piezoelectric layer 12, the lower thin film electrode 14 stacked on one surface of the piezoelectric layer 12, and the lower thin film electrode 14.
  • the lower protective layer 18, the upper thin film electrode 16 stacked on the other surface of the piezoelectric layer 12, and the upper protective layer 20 stacked on the upper thin film electrode 16 are provided, the present invention is not limited thereto.
  • an area where the piezoelectric layer 12 is exposed may be covered with an insulating layer for preventing a short circuit, a colored layer for covering a thin film electrode, and the like.
  • FIG. 4B is a cross-sectional view conceptually showing the layer structure of the conversion film 10 having a colored layer.
  • the layer structure of the conversion film shown in FIG. 4B includes a piezoelectric layer 12, a lower thin film electrode 14 stacked on one surface of the piezoelectric layer 12, a lower colored layer 21 stacked on the lower thin film electrode 14, The lower protective layer 18 laminated on the lower colored layer 21, the upper thin film electrode 16 laminated on the other surface of the piezoelectric layer 12, the upper colored layer 22 laminated on the upper thin film electrode 16, and the upper colored And an upper protective layer 20 stacked on the layer 22.
  • the rust of the upper thin film electrode 16 and the lower thin film electrode 14 can be made invisible from the outside.
  • the conversion film 10 may have an electrode lead-out portion that pulls out the electrodes from the upper thin film electrode 16 and the lower thin film electrode 14.
  • the thin film electrode and the protective layer may be provided with a protruding portion outside the surface of the piezoelectric layer, or a part of the protective layer may be removed.
  • a hole portion may be formed, and a conductive material such as a silver paste may be inserted into the hole portion to electrically connect the conductive material and the thin film electrode to form an electrode lead portion.
  • a configuration in which a hole is formed in the protective layer and a conductive material is inserted into the hole to form an electrode lead-out portion is preferable in terms of easy formation and miniaturization.
  • the number of electrode lead portions is not limited to one, and may include two or more electrode lead portions.
  • the piezoelectric layer 12 which is a polymer composite piezoelectric body, has piezoelectric particles 26 in a viscoelastic matrix 24 made of a polymer material having viscoelasticity at room temperature as conceptually shown in FIG. 4A. It is made of a polymer composite piezoelectric material that is uniformly dispersed.
  • “normal temperature” refers to a temperature range of about 0 to 50 ° C.
  • the piezoelectric layer 12 is preferably polarized.
  • the polymer composite piezoelectric material (piezoelectric layer 12) preferably has the following requirements.
  • (I) Flexibility For example, when gripping in a loosely bent state like a newspaper or a magazine for portable use, it is constantly subject 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 material is hard, a large bending stress is generated, and a crack is generated at the interface between the polymer matrix and the piezoelectric particles, which may eventually lead to destruction. Accordingly, the polymer composite piezoelectric body is required to have an appropriate softness. Further, if the strain energy can be diffused to the outside as heat, the stress can be relaxed.
  • the loss tangent of the polymer composite piezoelectric material is appropriately large.
  • (Ii) Sound quality The speaker vibrates the piezoelectric particles at an audio band frequency of 20 Hz to 20 kHz, and the vibration plate (polymer composite piezoelectric material) vibrates as a whole by the vibration energy, so that sound is reproduced.
  • the polymer composite piezoelectric body is required to have an appropriate hardness.
  • the frequency characteristic of the speaker is smooth, the amount of change in the sound quality when the lowest resonance frequency f 0 with the change in the curvature is changed becomes small. Therefore, the loss tangent of the polymer composite piezoelectric material is required to be moderately large.
  • the polymer composite piezoelectric body is required to behave hard for vibrations of 20 Hz to 20 kHz and to be soft for vibrations of several Hz or less.
  • the loss tangent of the polymer composite piezoelectric body is required to be reasonably large with respect to vibrations of all frequencies of 20 kHz or less.
  • polymer solids have a viscoelastic relaxation mechanism, and as the temperature increases or the frequency decreases, large-scale molecular motion decreases (relaxes) the storage elastic modulus (Young's modulus) or maximizes the loss elastic modulus (absorption). As observed. 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 remarkably.
  • Tg glass transition point
  • a polymer material having a glass transition point at room temperature in other words, a polymer material having viscoelasticity at room temperature is used as a matrix, so that vibrations of 20 Hz to 20 kHz can be prevented.
  • a polymer composite piezoelectric material that is hard and softly behaves with respect to slow vibrations of several Hz or less is realized.
  • a polymer material having a glass transition temperature at a frequency of 1 Hz at room temperature that is, 0 to 50 ° C., is preferably used for the matrix of the polymer composite piezoelectric material in terms of suitably exhibiting this behavior.
  • a polymer material having viscoelasticity at room temperature Preferably, a polymer material having a maximum value of loss tangent Tan ⁇ at a frequency of 1 Hz in a dynamic viscoelasticity test at room temperature, that is, 0 to 50 ° C., is 0.5 or more.
  • a polymer material having a maximum value of loss tangent Tan ⁇ at a frequency of 1 Hz in a dynamic viscoelasticity test at room temperature that is, 0 to 50 ° C.
  • the polymer material preferably has a storage elastic modulus (E ′) at a frequency of 1 Hz as measured by dynamic viscoelasticity of 100 MPa or more at 0 ° C. and 10 MPa or less at 50 ° C.
  • E ′ storage elastic modulus
  • the polymer material has a relative dielectric constant of 10 or more at 25 ° C.
  • the polymer material preferably has a relative dielectric constant of 10 or less at 25 ° C.
  • Polymer materials satisfying such conditions include cyanoethylated polyvinyl alcohol (cyanoethylated PVA), polyvinyl acetate, polyvinylidene chloride core acrylonitrile, polystyrene-vinyl polyisoprene block copolymer, polyvinyl methyl ketone, and polybutyl. Examples include methacrylate.
  • cyanoethylated polyvinyl alcohol cyanoethylated PVA
  • polyvinyl acetate polyvinylidene chloride core acrylonitrile
  • polystyrene-vinyl polyisoprene block copolymer polyvinyl methyl ketone
  • polybutyl examples include methacrylate.
  • polyvinylidene fluoride vinylidene fluoride-tetrafluoroethylene copolymer
  • vinylidene fluoride-trifluoroethylene copolymer vinylidene fluoride-trifluoroethylene copolymer
  • polyvinylidene fluoride-tetrafluoroethylene copolymer polyvinylidene fluoride-tetrafluoroethylene copolymer.
  • Fluoropolymers such as polymers, vinylidene cyanide-vinyl acetate copolymer, cyanoethyl cellulose, cyanoethyl hydroxy saccharose, cyanoethyl hydroxy cellulose, cyanoethyl hydroxy pullulan, cyanoethyl methacrylate, cyanoethyl acrylate, cyanoethyl hydroxyethyl cellulose, cyanoethyl amylose, cyanoethyl hydroxypropyl Cellulose, cyanoethyl dihydroxypropyl cellulose, cyanoethyl hydroxypropyl amino Cyanoethyl polyacrylamide, cyanoethyl polyacrylate, cyanoethyl pullulan, cyanoethyl polyhydroxymethylene, cyanoethyl glycidol pullulan, cyano group such as cyanoethyl saccharose and cyano
  • polystyrene resin polystyrene resin
  • Hibler 5127 manufactured by Kuraray Co., Ltd.
  • cyanoethylated PVA polystyrene resin
  • these polymeric materials may use only 1 type, and may use multiple types together (mixed).
  • the viscoelastic matrix 24 using the polymer material having viscoelasticity at room temperature may use a plurality of polymer materials in combination as necessary. That is, other dielectric polymer materials may be added to the viscoelastic matrix 24 as needed in addition to viscoelastic materials such as cyanoethylated PVA for the purpose of adjusting dielectric properties and mechanical properties. .
  • dielectric polymer materials examples include polyvinylidene fluoride, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-trifluoroethylene copolymer, and polyvinylidene fluoride-trifluoroethylene copolymer.
  • Fluorine polymers such as polyvinylidene fluoride-tetrafluoroethylene copolymer, vinylidene cyanide-vinyl acetate copolymer, cyanoethyl cellulose, cyanoethyl hydroxy saccharose, cyanoethyl hydroxy cellulose, cyanoethyl hydroxy pullulan, cyanoethyl methacrylate, cyanoethyl acrylate, cyanoethyl Hydroxyethyl cellulose, cyanoethyl amylose, cyanoethyl hydroxypropyl cellulose, cyanoethyl dihydroxypropyl cellulose, Synthesis of polymers having cyano groups or cyanoethyl groups, such as noethyl hydroxypropyl amylose, cyanoethyl polyacrylamide, cyanoethyl polyacrylate, cyanoethyl pullulan, cyanoethyl polyhydroxy
  • Examples thereof include rubber.
  • a polymer material having a cyanoethyl group is preferably used.
  • the dielectric polymer added to the viscoelastic matrix 24 of the piezoelectric layer 12 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. Also good.
  • thermoplastic resins such as vinyl chloride resin, polyethylene, polystyrene, methacrylic resin, polybutene, isobutylene, phenol resin, urea resin, melamine resin, Thermosetting resins such as alkyd resins and mica may be added.
  • a tackifier such as rosin ester, rosin, terpene, terpene phenol, petroleum resin, etc. may be added.
  • the viscoelastic matrix 24 of the piezoelectric layer 12 there is no particular limitation on the amount of addition of a polymer other than a viscoelastic material such as cyanoethylated PVA, but it is 30% by weight or less in the proportion of the viscoelastic matrix 24. Is preferable.
  • the characteristics of the polymer material to be added can be expressed without impairing the viscoelastic relaxation mechanism in the viscoelastic matrix 24, so that the dielectric constant is increased, the heat resistance is improved, and the adhesiveness to the piezoelectric particles 26 and the electrode layer is increased. A preferable result can be obtained in terms of improvement.
  • dielectric particles may be added to the viscoelastic matrix.
  • the dielectric particles are particles having a high relative dielectric constant of 80 or more at 25 ° C.
  • the dielectric particles include lead zirconate titanate (PZT), barium titanate (BaTiO 3 ), titanium oxide (TiO 2 ), strontium titanate (SrTiO 3 ), and lead lanthanum zirconate titanate (PLZT).
  • PZT lead zirconate titanate
  • BaTiO 3 barium titanate
  • TiO 2 titanium oxide
  • strontium titanate SrTiO 3
  • lead lanthanum zirconate titanate PZT
  • Examples thereof include zinc oxide (ZnO), solid solution (BFBT) of barium titanate and bismuth ferrite (BiFeO 3 ), and the like.
  • barium titanate (BaTiO 3 ) as the dielectric particles in terms of having a high relative dielectric constant.
  • the dielectric particles preferably have an average particle size of 0.5 ⁇ m or less. Further, the volume fraction of the dielectric particles with respect to the total volume of the viscoelastic matrix and the dielectric particles is preferably 5 to 45%, more preferably 10 to 30%, and particularly preferably 20 to 30%.
  • the piezoelectric particles 26 are made of ceramic particles having a perovskite type or wurtzite type crystal structure.
  • the ceramic particles constituting the piezoelectric particles 26 include lead zirconate titanate (PZT), lead lanthanum zirconate titanate (PLZT), barium titanate (BaTiO3), zinc oxide (ZnO), and titanium.
  • PZT lead zirconate titanate
  • PLATiO3 barium titanate
  • ZnO zinc oxide
  • titanium titanium.
  • Examples thereof include a solid solution (BFBT) of barium acid and bismuth ferrite (BiFe3).
  • the particle size of the piezoelectric particles 26 may be appropriately selected according to the size and application of the conversion film 10, but is preferably 1 to 10 ⁇ m according to the study of the present inventors. By setting the particle size of the piezoelectric particles 26 within the above range, a favorable result can be obtained in terms of achieving both high piezoelectric characteristics and flexibility.
  • the piezoelectric particles 26 in the piezoelectric layer 12 are uniformly and regularly dispersed in the viscoelastic matrix 24, but the present invention is not limited to this. That is, the piezoelectric particles 26 in the piezoelectric layer 12 may be irregularly dispersed in the viscoelastic matrix 24 as long as it is preferably dispersed uniformly.
  • the quantity ratio between the viscoelastic matrix 24 and the piezoelectric particles 26 in the piezoelectric layer 12 is required for the size and thickness of the conversion film 10 in the surface direction, the use of the conversion film 10, and the conversion film 10. What is necessary is just to set suitably according to the characteristic etc. to be.
  • the volume fraction of the piezoelectric particles 26 in the piezoelectric layer 12 is preferably 30 to 70%, particularly preferably 50% or more. 70% is more preferable.
  • the thickness of the piezoelectric layer 12 is not particularly limited, and is appropriately set according to the size of the conversion film 10, the use of the conversion film 10, the characteristics required for the conversion film 10, and the like. do it.
  • the thickness of the piezoelectric layer 12 is preferably 8 to 300 ⁇ m, more preferably 8 to 40 ⁇ m, further preferably 10 to 35 ⁇ m, and particularly preferably 15 to 25 ⁇ m.
  • the piezoelectric layer 12 is preferably polarized (polled) as described above. The polarization process will be described in detail later.
  • the upper protective layer 20 and the lower protective layer 18 cover and protect the upper thin film electrode 16 and the lower thin film electrode 14, and also provide the piezoelectric layer 12 with appropriate rigidity and mechanical strength. I'm in charge. That is, in the conversion film 10 of the present invention, the piezoelectric layer 12 composed of the viscoelastic matrix 24 and the piezoelectric particles 26 exhibits very excellent flexibility against slow bending deformation, Depending on the application, rigidity and mechanical strength may be insufficient.
  • the conversion film 10 is provided with an upper protective layer 20 and a lower protective layer 18 to supplement it.
  • the upper protective layer 20 and the lower protective layer 18 are not particularly limited, and various sheet materials can be used.
  • various resin films are preferably exemplified.
  • PET polyethylene terephthalate
  • PP polypropylene
  • PS polystyrene
  • PC polycarbonate
  • PPS polyphenylene sulfite
  • PMMA polymethyl methacrylate
  • PEI Polyetherimide
  • PEI polyimide
  • PA polyamide
  • PEN polyethylene naphthalate
  • TAC triacetylcellulose
  • cyclic olefin-based resin are preferably used.
  • the thickness of the upper protective layer 20 and the lower protective layer 18 is not particularly limited.
  • the thicknesses of the upper protective layer 20 and the lower protective layer 18 are basically the same, but may be different.
  • the rigidity of the upper protective layer 20 and the lower protective layer 18 is too high, not only the expansion and contraction of the piezoelectric layer 12 is restricted, but also the flexibility is impaired, so that the mechanical strength and the sheet-like material are good.
  • the upper protective layer 20 and the lower protective layer 18 are more advantageous as they are thinner.
  • the thicknesses of the upper protective layer 20 and the lower protective layer 18 are preferably 50 ⁇ m or less, more preferably 25 ⁇ m or less, and particularly preferably 10 ⁇ m or less.
  • an upper thin film electrode (hereinafter also referred to as an upper electrode) 16 is provided between the piezoelectric layer 12 and the upper protective layer 20, and a lower thin film electrode is provided between the piezoelectric layer 12 and the lower protective layer 18. (Hereinafter also referred to as a lower electrode) 14 are formed.
  • the upper electrode 16 and the lower electrode 14 are provided for applying an electric field to the conversion film 10 (piezoelectric layer 12).
  • the material for forming the upper electrode 16 and the lower electrode 14 is not particularly limited, and various conductors can be used. Specifically, carbon, palladium, iron, tin, aluminum, nickel, platinum, gold, silver, copper, chromium, molybdenum and the like, alloys thereof, indium tin oxide, PEDOT / PPS (polyethylenedioxythiophene-polystyrenesulfone) Examples thereof include conductive polymers such as (acid). Among these, any of copper, aluminum, gold, silver, platinum, and indium tin oxide is preferably exemplified, and copper is more preferable from the viewpoint of conductivity, cost, flexibility, and the like.
  • the method for forming the upper electrode 16 and the lower electrode 14 is not particularly limited, and a vapor deposition method (vacuum film forming method) such as vacuum vapor deposition or sputtering, film formation by plating, or a foil formed of the above materials.
  • a vapor deposition method vacuum film forming method
  • Various known methods such as a method of sticking and a method of applying can be used.
  • a thin film of copper or aluminum formed by vacuum vapor deposition is preferably used as the upper electrode 16 and the lower electrode 14 because, for example, the flexibility of the conversion film 10 can be ensured.
  • a copper thin film formed by vacuum deposition is particularly preferably used.
  • the thicknesses of the upper electrode 16 and the lower electrode 14 are not particularly limited. The thicknesses of the upper electrode 16 and the lower electrode 14 are basically the same, but may be different.
  • the thicknesses of the upper electrode 16 and the lower electrode 14 are preferably 1.2 ⁇ m or less, more preferably 0.3 ⁇ m or less, and particularly preferably 0.1 ⁇ m or less.
  • the upper colored layer 22 is formed between the upper electrode 16 and the upper protective layer 20, and the lower colored layer 21 is formed between the lower electrode 14 and the lower protective layer 18, respectively. It may be.
  • the upper colored layer 22 and the lower colored layer 21 are for preventing the rust of the upper electrode 16 and the lower electrode 14 from being visible from the outside.
  • the transmission density of the upper colored layer 22 and the lower colored layer 21 is preferably 0.3 or more, more preferably 0.5 or more. Is more preferable.
  • the transmission density is an optical density measured as a ratio of the transmitted light to the incident light.
  • the transmittance when the transmission density is 0.3 is about 50%, and the transmittance when the transmission density is 0.5. Is about 30%.
  • the piezoelectric layer 12 expands and contracts. Since the upper colored layer 22 and the lower colored layer 21 are not limited to be restricted, the upper colored layer 22 and the lower colored layer 21 are more advantageous as long as the transmission density is not too low. According to the study of the present inventors, the thickness of the upper colored layer 22 and the lower colored layer 21 is preferably 1 ⁇ m or less, more preferably 100 nm or less, and particularly preferably 40 nm or less.
  • the upper colored layer 22 and the lower colored layer 21 preferably have a low electrical resistivity, preferably 1 ⁇ 10 ⁇ 7 ⁇ m or less.
  • a hole is formed by removing a part of the protective layer, and a conductive material such as silver paste is formed in the hole.
  • the conductive material and the thin film electrode can be electrically connected without removing the upper colored layer 22 and the lower colored layer 21 at the positions of the holes. Can be conducted.
  • the material for forming the upper colored layer 22 and the lower colored layer 21 is not particularly limited as long as it satisfies the above transmission density and does not change color due to rust or the like.
  • the material for forming the upper colored layer 22 and the lower colored layer 21 includes metals such as nickel, titanium, aluminum, gold, platinum, and chromium, carbon black (CB), titanium oxide, zinc oxide, barium sulfate, and the like.
  • the conversion film can be colored in various colors, it is preferable to use various pigments as the upper colored layer 22 and the lower colored layer 21.
  • the formation method of the upper colored layer 22 and the lower colored layer 21 there is no limitation in particular in the formation method of the upper colored layer 22 and the lower colored layer 21, What is necessary is just to form by various well-known methods according to the said material.
  • a vapor deposition method vacuum film forming method
  • a coating method, printing, or the like can be used.
  • a method of transferring a colored layer formed in advance can also be used.
  • the upper colored layer 22 and the lower colored layer 21 are formed between the upper electrode 16 and the upper protective layer 20 and between the lower electrode 14 and the lower protective layer 18, respectively.
  • the present invention is not limited to this, and any structure may be used as long as it is formed on the surface layer side with respect to the upper electrode 16 and on the surface layer side with respect to the lower electrode 14. That is, for example, the upper electrode 16, the upper protective layer 20, and the upper colored layer 22 are formed in this order on one surface of the piezoelectric layer 12, and the lower electrode 14 and the lower protective layer 18 are formed on the other surface of the piezoelectric layer 12.
  • the lower colored layer 21 may be formed in this order.
  • each of the upper electrode 16 side and the lower electrode 14 side has a colored layer.
  • the present invention is not limited to this, and the colored layer is provided on at least one side. It may be.
  • the conversion film of this invention may contain functional layers, such as a contact
  • the conversion film 10 includes at least the piezoelectric layer 12 in which the piezoelectric particles 26 are dispersed in the viscoelastic matrix 24 having viscoelasticity at room temperature, and is sandwiched between the upper electrode 16 and the lower electrode 14.
  • the body has a layer structure in which an upper protective layer 20 and a lower protective layer 18 are sandwiched.
  • Such a conversion film 10 preferably has a maximum value at room temperature at which the loss tangent (Tan ⁇ ) at a frequency of 1 Hz as measured by dynamic viscoelasticity measurement is 0.1 or more.
  • the strain energy can be effectively diffused to the outside as heat, so that the polymer matrix and the piezoelectric particles It is possible to prevent cracks from occurring at the interface.
  • the conversion film 10 preferably has a storage elastic modulus (E ′) at a frequency of 1 Hz as measured by dynamic viscoelasticity of 10 to 30 GPa at 0 ° C. and 1 to 10 GPa at 50 ° C.
  • the conversion film 10 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 conversion film 10 can be equipped with moderate rigidity and mechanical strength.
  • the conversion film 10 preferably has a loss tangent (Tan ⁇ ) at 25 ° C. and a frequency of 1 kHz in a master curve obtained from dynamic viscoelasticity measurement of 0.05 or more.
  • Ton ⁇ loss tangent
  • the conversion frequency characteristic of the loudspeaker using the film 10 becomes smooth, can vary the amount of sound is also small when the lowest resonance frequency f 0 with the change in the curvature of the speaker has changed.
  • FIG. 5 is a sectional view conceptually showing an example of the electroacoustic transducer of the present invention.
  • the electroacoustic transducer 60 shown in FIG. 5 uses the conversion film 10 as a diaphragm.
  • the electroacoustic transducer 60 when the conversion film 10 expands in the in-plane direction by applying a voltage to the conversion film 10, the conversion film 10 moves upward (in the protruding direction of the convex portion) to absorb this extension. On the contrary, when the conversion film 10 contracts in the in-plane direction by applying a voltage to the conversion film 10, the conversion film 10 is moved downward (on the side opposite to the protruding direction of the convex portion) to absorb this contraction. Direction).
  • the electroacoustic transducer 60 converts vibration (sound) and an electric signal by vibration caused by repeated expansion and contraction of the conversion film 10.
  • the electroacoustic transducer 60 includes the conversion film 10 and two support members 48.
  • the support member 48 is a plate-like member that is formed of plastic, metal, wood, or the like and has a through hole in the center.
  • the shape of the through hole is substantially the same as the shape of the convex portion 10a when viewed from the direction perpendicular to the main surface of the conversion film 10, and is a circular shape having a diameter Ds in the illustrated example.
  • the method for fixing the two support members 48 is not particularly limited, and various known methods such as a method using screws and bolts and nuts and a method using a fixing jig can be used.
  • the convex portion 10a of the conversion film 10 is a region that actually vibrates.
  • the convex portion 10a is a region that actually vibrates.
  • the expansion and contraction in the surface direction of the conversion film is transmitted to a region other than the convex portion 10a.
  • the vibration of the convex portion 10a can be efficiently performed.
  • an elastic support for curving the conversion film 10 and a structure for applying air pressure are unnecessary, a structure in which both surfaces of the conversion film 10 are open can be used. Therefore, the heat generated by driving the conversion film 10 can be efficiently dissipated, and the heat dissipation can be enhanced.
  • the width of the edge portion of the support member 48 is not particularly limited as long as the edge portion of the conversion film 10 can be suitably supported, but is preferably 20 mm or less, and preferably 1 mm to 10 mm.
  • the two support members 48 are configured to sandwich the entire periphery of the edge portion of the convex portion 10a of the conversion film 10, but this is not a limitation, and at least a part of the edge portion is not limited thereto. It is good also as a structure which pinches
  • the convex portion when a conversion film having a convex portion is incorporated in an electroacoustic transducer, the convex portion may be arranged outward, and the convex portion is arranged inward (that is, the concave portion is directed outward). May be.
  • the conversion film having a convex part is formed in a convex shape, a viscoelastic support for curving the conversion film and a structure for applying pressure to the inside of the case are not necessary. You may use it in combination.
  • the manufacturing method of the conversion film of the present invention includes a polymer composite piezoelectric material in which piezoelectric particles are dispersed in a viscoelastic matrix made of a polymer material having viscoelasticity at room temperature, and laminated on both surfaces of the polymer composite piezoelectric material.
  • the laminated body prepared in the preparation process is manufactured as follows as an example.
  • a sheet-like object 11a in which the lower electrode 14 is formed on the lower protective layer 18 is prepared.
  • the sheet-like material 11a may be produced by forming a copper thin film or the like as the lower electrode 14 on the surface of the lower protective layer 18 by vacuum deposition, sputtering, plating, or the like.
  • the lower protective layer 18 with a separator temporary support
  • PET or the like having a thickness of 25 to 100 ⁇ m can be used.
  • what is necessary is just to remove a separator just before forming a side surface insulating layer, a 2nd protective layer, etc. after thermocompression bonding of a thin film electrode and a protective layer.
  • a polymer material having viscoelasticity such as cyanoethylated PVA is dissolved in an organic solvent, and piezoelectric particles 26 such as PZT particles are added and stirred.
  • a paint is prepared which is dispersed.
  • the organic solvent is not particularly limited, and various organic solvents such as dimethylformamide (DMF), methyl ethyl ketone, and cyclohexanone can be used.
  • DMF dimethylformamide
  • methyl ethyl ketone methyl ethyl ketone
  • cyclohexanone can be used.
  • the coating casting method is not particularly limited, and all known methods (coating apparatuses) 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, and a melt obtained by adding / dispersing the piezoelectric particles 26 is prepared and extruded.
  • the first laminated body 11b as shown in FIG. 6B may be produced by extruding the sheet-like material 11a shown in FIG.
  • a polymer piezoelectric material such as PVDF may be added to the viscoelastic matrix 24 in addition to a viscoelastic material such as cyanoethylated PVA.
  • a viscoelastic material such as cyanoethylated PVA.
  • the polymer piezoelectric material added to the paint may be dissolved.
  • the polymer piezoelectric material to be added may be added to the heat-melted viscoelastic material and heat-melted.
  • the method for polarization treatment of the piezoelectric layer 12 is not particularly limited, and a known method can be used. As a preferable method of polarization treatment, the method shown in FIGS. 6C and 6D is exemplified.
  • a gap g is formed, for example, by 1 mm, or a rod-shaped or movable along the upper surface 12a.
  • a wire-shaped corona electrode 30 is provided.
  • the corona electrode 30 and the lower electrode 14 are connected to a DC power source 32.
  • a heating means for heating and holding the first stacked body 11b for example, a hot plate is prepared.
  • the piezoelectric layer 12 is heated and held at, for example, a temperature of 100 ° C. by a heating means, and a direct current of several kV, for example, 6 kV, is connected between the lower electrode 14 and the corona electrode 30 from the DC power source 32. A voltage is applied to cause corona discharge. Further, the corona electrode 30 is moved (scanned) along the upper surface 12a of the piezoelectric layer 12 while maintaining the gap g, and the piezoelectric layer 12 is polarized.
  • a direct current of several kV for example, 6 kV
  • the corona electrode 30 may be moved by using a known rod-like moving means.
  • the method for moving the corona electrode 30 is not limited. That is, the corona electrode 30 may be fixed and a moving mechanism for moving the first stacked body 11b may be provided, and the first stacked body 11b may be moved to perform the polarization treatment. The movement of the first laminated body 11b may be performed by using a known sheet-like moving means.
  • the number of corona electrodes 30 is not limited to one, and a plurality of corona electrodes 30 may be used to perform corona poling treatment.
  • the polarization process is not limited to the corona polling process, and normal electric field poling in which a direct current electric field is directly applied to a target to be polarized can also be used.
  • normal electric field poling it is necessary to form the upper electrode 16 before the polarization treatment.
  • the sheet-like object 11c in which the upper electrode 16 is formed on the upper protective layer 20 is prepared.
  • the sheet-like material 11c may be manufactured by forming a copper thin film or the like as the upper electrode 16 on the surface of the upper protective layer 20 by vacuum deposition, sputtering, plating, or the like.
  • the upper electrode 16 is directed toward the piezoelectric layer 12, and the sheet-like material 11 c is stacked on the first stacked body 11 b that has finished the polarization treatment of the piezoelectric layer 12.
  • the laminated body of the first laminated body 11b and the sheet-like material 11c is subjected to thermocompression bonding with a heating press device, a heating roller pair or the like so as to sandwich the upper protective layer 20 and the lower protective layer 18, A two-layered product 11d is produced.
  • the 2nd laminated body 11d is a laminated body prepared by a preparatory process in this invention.
  • the produced second laminated body 11d is heated and compression-molded, and the convex portion 10a protruding to one main surface side of the conversion film 10 (second laminated body 11d) is molded.
  • the method for heat compression molding is not particularly limited, and various known resin film processing methods can be used. As an example, as shown in FIGS. 7A and 7B, by using a molding apparatus having molds 70a and 70b having a shape corresponding to the shape of the convex portion 10a to be molded, the second laminate 11d is heat compression molded. The convex portion 10a having a desired shape can be molded.
  • Example 1 The conversion film 10 shown in FIG. 1 was produced by the method shown in FIGS. 6A to 6E and FIGS. 7A to 7B.
  • cyanoethylated PVA CR-V manufactured by Shin-Etsu Chemical Co., Ltd.
  • MEK methyl ethyl ketone
  • PZT particles were added to the solution at the following composition ratio and dispersed with a propeller mixer (rotation speed: 2000 rpm) to prepare a coating material for forming the piezoelectric layer 12.
  • PZT particles ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ 1000 parts by mass ⁇ Cyanoethylated PVA ⁇ ⁇ ⁇ ⁇ ⁇ 100 parts by mass ⁇ MEK ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ 600 parts by mass
  • PZT particles commercially available PZT raw material powders were sintered at 1000 to 1200 ° C., and then crushed and classified so as to have an average particle size of 3.5 ⁇ m.
  • sheet-like materials 11a and 11c were prepared by vacuum-depositing a 0.1 ⁇ m-thick copper thin film on a 4 ⁇ m-thick PET film by vacuum deposition. That is, in this example, the upper electrode 16 and the lower electrode 14 are copper-deposited thin films having a thickness of 0.1 ⁇ m, and the upper protective layer 20 and the lower protective layer 18 are PET films having a thickness of 4 ⁇ m. In order to obtain good handling during the process, a PET film with a 50 ⁇ m thick separator (temporary support PET) was used, and the separator of each protective layer was removed after thermocompression of the sheet-like material 11c. It was.
  • temporary support PET temporary support PET
  • the first laminated body 11b having the copper lower electrode 14 on the lower protective layer 18 made of PET and the piezoelectric layer 12 (piezoelectric layer) having a thickness of 20 ⁇ m formed thereon is formed.
  • the first laminated body 11b having the copper lower electrode 14 on the lower protective layer 18 made of PET and the piezoelectric layer 12 (piezoelectric layer) having a thickness of 20 ⁇ m formed thereon is formed.
  • the piezoelectric layer 12 of the laminate 11b was polarized by the above-described corona poling shown in FIGS. 6C and 6D.
  • the polarization treatment was performed by setting the temperature of the piezoelectric layer 12 to 100 ° C. and applying a DC voltage of 6 kV between the lower electrode 14 and the corona electrode 30 to cause corona discharge.
  • a mixture of cyanoethylated pullulan and cyanoethylated PVA (CR-M manufactured by Shin-Etsu Chemical Co., Ltd.) is 0.3 ⁇ m on the upper electrode 16 (copper thin film side) on the first laminated body 11b subjected to the polarization treatment.
  • the sheet-like material 11c was laminated so that the coated surface applied to the piezoelectric material layer 12 faced.
  • the laminated body of the first laminated body 11b and the sheet-like material 11c is thermocompression bonded at 120 ° C. using a laminator device to bond the piezoelectric body layer 12, the upper electrode 16 and the lower electrode 14 to each other.
  • a two-layered body 11d was produced.
  • the produced second laminated body 11d is cut into a size of 50 mm ⁇ 50 mm, and a hot press apparatus (with a mold having a shape corresponding to the shape of the convex portion 10a to be molded, as shown in FIGS. 7A and 7B, is used.
  • the electroacoustic conversion film 10 was produced by molding into a shape having a convex portion 10a as shown in FIG. 1 by a heat compression molding method using AH-2003) manufactured by ASONE.
  • the shape of the convex part 10a was made into the shape which consists of a part of sphere.
  • vertical to the main surface of the conversion film 10 was 40 mm, and height was 0.5 mm. That is, the ratio H / Ds between the height H of the convex portion and the minor axis Ds was set to 0.01.
  • each of the upper protective layer 20 side and the lower protective layer 18 side of the produced conversion film 10 a part of the protective layer is removed by cutting to form a hole, and a conductive material such as silver paste is formed in the hole.
  • the conductive material and the thin film electrode were electrically connected to form an electrode lead portion.
  • An electroacoustic transducer 60 as shown in FIG. 5 was produced by sandwiching the edge portion of the produced conversion film 10 with two support members 48.
  • the support member 48 is a plate-like member having a through hole in the center and made of acrylic.
  • the outer shape is 50 mm ⁇ 50 mm
  • the size of the through hole is a circle of ⁇ 40 mm
  • the thickness is 3 mm.
  • Example 2 to 6 The electroacoustic conversion film 10 and the electroacoustics were the same as in Example 1 except that the height H of the convex portion 10a and the ratio H / Ds of the height H to the minor axis Ds were changed to the values shown in Table 1, respectively. A transducer 60 was produced.
  • Example 7 to 9 An electroacoustic conversion film 10 and an electroacoustic transducer 60 were produced in the same manner as in Example 3 except that the thicknesses of the upper protective layer 20 and the lower protective layer 18 were changed as shown in Table 1 below.
  • Example 10 Example 2 was performed except that the two support members 48 were not provided. That is, the below-mentioned evaluation was performed with the electroacoustic conversion film 10 alone.
  • Example 11 The electroacoustic transducer film 10 and the electroacoustic transducer 60 were produced in the same manner as in Example 3 except that the shape of the convex portion 10a was molded into a shape having a flat top as shown in FIG. 3A.
  • Example 12 An electroacoustic conversion film 10 and an electroacoustic transducer 60 were produced in the same manner as in Example 3 except that the electrode lead-out portions were provided at two locations on each of the upper protective layer 20 side and the lower protective layer 18 side.
  • Example 13 The electroacoustic conversion film 10 and the electroacoustic transducer 60 were produced in the same manner as in Example 3 except that a polyamide film having a thickness of 4 ⁇ m was used as the upper protective layer 20 and the lower protective layer 18.
  • Example 14 As the sheet-like materials 11a and 11c, a nickel thin film having a thickness of 20 nm was formed on a PET film having a thickness of 4 ⁇ m by vacuum deposition, and a copper thin film having a thickness of 0.1 ⁇ m was further vacuum deposited on the nickel thin film.
  • An electroacoustic conversion film 10 and an electroacoustic transducer 60 were produced in the same manner as in Example 3 except that those were used. That is, in the conversion film (second laminate) of Example 15, the lower electrode 14, the lower colored layer 21, and the lower protective layer 18 are laminated in this order on one surface of the piezoelectric layer 12, as shown in FIG. 4B. The upper electrode 16, the upper colored layer 22, and the upper protective layer 20 are stacked in this order on the other surface of the piezoelectric layer 12.
  • Example 1 The electroacoustic conversion film and the electroacoustic transducer were obtained in the same manner as in Example 1 except that the height H of the convex portion was 8 mm and the ratio H / Ds of the height H to the minor axis Ds was 0.2. Produced.
  • Example 2 An electroacoustic conversion film was produced in the same manner as in Example 1 except that the convex portions were not formed. That is, the second laminate before molding the convex portions was used as the conversion film 102. Using this conversion film 102, an electroacoustic transducer 100 as shown in FIG. 8A was produced.
  • An electroacoustic transducer 100 shown in FIG. 8A includes a case 104 having a thin cylindrical shape and one of the largest surfaces being an open surface, an elastic support 106 accommodated in the case 104, an open surface of the case 104, and an elastic support.
  • the case 104 is a cylindrical container with one open surface, and a plastic container having an outer size of 50 mm ⁇ 50 mm, a height of 6 mm, an opening size of ⁇ 40 mm, and a depth of 3 mm was used.
  • the elastic support 106 was made of felt having a size of 40 mm, a height of 10 mm before assembly, and a density of 250 kg / m 3 .
  • As the pressing member 108 an acrylic plate-like member having an opening size of 40 mm and a thickness of 3 mm was used.
  • the conversion film 102 is curved and held in a convex shape by the elastic support 106.
  • the bending height was 2 mm.
  • Comparative Example 3 It was the same as Comparative Example 2 except that an electroacoustic transducer 110 as shown in FIG. That is, the 2nd laminated body before shape
  • FIG. 1 An electroacoustic transducer 110 as shown in FIG. That is, the 2nd laminated body before shape
  • the electroacoustic transducer 110 shown in FIG. 8B includes an airtight case 104, a pipe 104 a for introducing air into the case 104, a conversion film 102 that covers the open surface of the case 104, and a case 104. And a holding lid 112 fitted to the outer periphery.
  • the presser lid 112 is a frame-like member having a substantially L-shaped cross section having an inner periphery substantially the same as the outer periphery of the case 104, and is fitted to the outer periphery of the case 104.
  • the conversion film 102 is pressed and fixed to the open surface of the case 104, and the inside of the case 104 is hermetically closed by the conversion film 102.
  • Example 4 A commercially available PVDF (Poly Vinylidene DiFluoride) with a thickness of 20 ⁇ m was used as a piezoelectric layer, and a conversion film was molded using a laminate in which the upper electrode and the lower electrode were formed on both sides of the PVDF by vacuum vapor deposition as a second laminate. Except for the above, an electroacoustic conversion film and an electroacoustic transducer were produced in the same manner as in Example 3.
  • PVDF Poly Vinylidene DiFluoride
  • the heat dissipation of the produced electroacoustic transducer was evaluated as follows. First, a 10 kHz, 20V 0-P sine wave was input for 15 minutes between the upper electrode and the lower electrode of the conversion film of the electroacoustic transducer in an environment of room temperature of 25 ° C. After continuous driving for 15 minutes, the surface temperature of the conversion film was measured and evaluated according to the following criteria. A: Room temperature + less than 1.5 ° C B: Room temperature + 1.5 ° C or more and room temperature + less than 3.0 ° C C: Room temperature + 3.0 ° C or more and room temperature + 5.0 ° C D: Room temperature + 5.0 ° C or higher
  • Examples 1 to 15 of the electroacoustic conversion film of the present invention are better in comparison with Comparative Examples 1 to 4 in all of sound pressure level, heat resistance and durability against change over time. You can see that Further, the comparison between Examples 1 to 6 and Comparative Example 1 shows that the lower the height of the convex portion, the better the sound pressure level is improved, and the ratio H / Ds of the minor axis Ds to the height H is 0. .15 or less, 0.1 or less is preferable, 0.075 or less is more preferable, and 0.005 or less is particularly preferable.

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  • Physics & Mathematics (AREA)
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Abstract

L'invention concerne : un film de conversion électroacoustique qui est capable d'une reproduction avec un volume sonore suffisant et présente des propriétés de dissipation de chaleur élevée, tout en supprimant la variation de pression acoustique au cours du temps ; un procédé de production d'un film de conversion électroacoustique ; et un transducteur électroacoustique. Ce film de conversion électroacoustique est obtenu en stratifiant : un corps piézoélectrique composite en polymère qui est obtenu en dispersant des particules piézoélectriques dans une matrice viscoélastique qui est constituée d'un matériau polymère qui présente une viscoélasticité à température ambiante ; deux électrodes en couche mince qui sont respectivement stratifiées sur les deux surfaces du corps piézoélectrique composite en polymère ; et deux couches de protection qui sont stratifiées respectivement sur les deux électrodes en couche mince. Ce film de conversion électroacoustique présente une partie en saillie qui est moulée pour avoir une forme convexe dépassant d'un côté de surface principale, et le rapport entre la hauteur moulée (H) de la partie en saillie et la largeur (Ds) de la partie en saillie en vue à partir d'une direction perpendiculaire à la surface principale, c'est-à-dire H/Ds, respecte 0 < H/Ds ≤ 0,15.
PCT/JP2016/073413 2015-08-18 2016-08-09 Film de conversion électroacoustique, procédé de fabrication d'un film de conversion électroacoustique et transducteur électroacoustique WO2017030045A1 (fr)

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WO2021075204A1 (fr) * 2019-10-15 2021-04-22 富士フイルム株式会社 Élément piézoélectrique
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CN112216786B (zh) * 2019-07-09 2022-05-17 北京大学 一种柔性压电高分子微机械能采集器及其制备方法
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WO2025005132A1 (fr) * 2023-06-30 2025-01-02 富士フイルム株式会社 Unité d'attaque et casque d'écoute

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