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WO2017209080A1 - Piezoelectric film - Google Patents

Piezoelectric film Download PDF

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Publication number
WO2017209080A1
WO2017209080A1 PCT/JP2017/019979 JP2017019979W WO2017209080A1 WO 2017209080 A1 WO2017209080 A1 WO 2017209080A1 JP 2017019979 W JP2017019979 W JP 2017019979W WO 2017209080 A1 WO2017209080 A1 WO 2017209080A1
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WO
WIPO (PCT)
Prior art keywords
piezoelectric film
coating layer
piezoelectric
layer
piezoelectricity
Prior art date
Application number
PCT/JP2017/019979
Other languages
French (fr)
Japanese (ja)
Inventor
浩史 別府
孝伸 矢野
基希 拝師
憲俊 木曽
智剛 梨木
Original Assignee
日東電工株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP2017104590A external-priority patent/JP2017216450A/en
Application filed by 日東電工株式会社 filed Critical 日東電工株式会社
Priority to KR1020187028511A priority Critical patent/KR20190015188A/en
Priority to CN201780033533.1A priority patent/CN109196673A/en
Publication of WO2017209080A1 publication Critical patent/WO2017209080A1/en

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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
    • H10N30/01—Manufacture or treatment
    • H10N30/07—Forming of piezoelectric or electrostrictive parts or bodies on an electrical element or another base
    • H10N30/074—Forming of piezoelectric or electrostrictive parts or bodies on an electrical element or another base by depositing piezoelectric or electrostrictive layers, e.g. aerosol or screen printing
    • H10N30/077—Forming of piezoelectric or electrostrictive parts or bodies on an electrical element or another base by depositing piezoelectric or electrostrictive layers, e.g. aerosol or screen printing by liquid phase deposition
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
    • C08J7/04—Coating
    • C08J7/043—Improving the adhesiveness of the coatings per se, e.g. forming primers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
    • C08J7/04—Coating
    • C08J7/046—Forming abrasion-resistant coatings; Forming surface-hardening coatings
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00—Measuring force or stress, in general
    • G01L1/16—Measuring force or stress, in general using properties of piezoelectric devices
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
    • G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
    • 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
    • H10N30/704—Piezoelectric or electrostrictive devices based on piezoelectric or electrostrictive films or coatings
    • H10N30/706—Piezoelectric or electrostrictive devices based on piezoelectric or electrostrictive films or coatings characterised by the underlying bases, e.g. substrates
    • H10N30/708—Intermediate layers, e.g. barrier, adhesion or growth control buffer layers
    • 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
    • H10N30/857—Macromolecular compositions
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/30—Piezoelectric or electrostrictive devices with mechanical input and electrical output, e.g. functioning as generators or sensors
    • H10N30/302—Sensors

Definitions

  • the present invention relates to a piezoelectric film.
  • a touch panel detects a two-dimensional position on the surface of a finger or pen that touches the surface of the touch panel.
  • finger or pen is simply referred to as “finger”, and the two-dimensional position on the surface of the touch panel of the finger or pen is referred to as “finger XY coordinates”.
  • the pressure touched by the finger cannot be detected.
  • the magnitude of the pressure touched by the finger is considered to be in the Z-axis direction and is referred to as the “Z coordinate of the finger”. That is, regardless of the magnitude of the pressure touched by the finger (Z coordinate of the finger) Only the XY coordinates of the finger touch position are detected.
  • Such a touch panel that can detect the pressure (Z coordinate of the finger) touched by a finger is described in, for example, Japanese Patent Application Laid-Open No. 2010-26938.
  • a laminate in which transparent electrodes are laminated on both sides of a piezoelectric layer containing a polyvinylidene fluoride-tetrafluoroethylene copolymer is used.
  • the thickness of the piezoelectric layer containing the polyvinylidene fluoride-tetrafluoroethylene copolymer is 20 ⁇ m to 300 ⁇ m.
  • the piezoelectric layer containing the polyvinylidene fluoride-tetrafluoroethylene copolymer of Patent Document 1 is described as being produced by a casting method or an extrusion method, a self-supporting film (a film not laminated on another film) )it is conceivable that.
  • Patent Document 1 describes that a piezoelectric layer containing a polyvinylidene fluoride-tetrafluoroethylene copolymer has a haze value (cloudiness value) of 5% to 7% and a total light transmittance of 95%.
  • the haze value and the total light transmittance in the examples of Patent Document 1 are values of the piezoelectric layer alone containing the polyvinylidene fluoride-tetrafluoroethylene copolymer before the transparent electrode is laminated.
  • the visibility of the image on the display on the back of the touch panel is affected at least by the haze value and the total light transmittance of the piezoelectric film. Since the piezoelectric layer containing the polyvinylidene fluoride-tetrafluoroethylene copolymer of Patent Document 1 has a large haze value, the visibility of the display image on the back surface of the touch panel may be lowered.
  • an object of the present invention is to realize a piezoelectric film having a small haze value and a high total light transmittance.
  • the piezoelectric film of the present invention includes a laminate of a base film and a piezoelectric coating layer.
  • the piezoelectric film of the present invention includes an undercoat layer between the base film and the coating layer having piezoelectricity.
  • the piezoelectric film of the present invention includes at least one optical adjustment layer on the surface of the coating layer having piezoelectricity opposite to the base film.
  • the at least one optical adjustment layer means that the optical adjustment layer may be a multilayer film having two or more layers.
  • the piezoelectric film of the present invention includes at least one first optical adjustment layer between the base film and the coating layer having piezoelectricity.
  • the at least one first optical adjustment layer means that the first optical adjustment layer may be a multilayer film of two or more layers.
  • the piezoelectric film of the present invention includes at least one second optical adjustment layer on the surface of the coating layer having piezoelectricity opposite to the first optical adjustment layer.
  • the term “at least one second optical adjustment layer” means that the second optical adjustment layer may be a multilayer film including two or more layers.
  • the piezoelectric film of the present invention includes at least one anti-blocking layer between the base film and the coating layer having piezoelectricity.
  • the at least one anti-blocking layer means that the anti-blocking layer may be a multilayer film having two or more layers.
  • the piezoelectric film of the present invention includes at least one anti-blocking layer on the surface of the base film opposite to the piezoelectric coating layer.
  • the piezoelectric film of the present invention includes at least one transparent adhesive layer on the surface of the coating layer having piezoelectricity opposite to the base film.
  • the at least one transparent adhesive layer means that the transparent adhesive layer may be a multilayer film having two or more layers.
  • the piezoelectric film of the present invention includes at least one transparent adhesive layer on the surface of the base film opposite to the piezoelectric coating layer.
  • the coating layer having piezoelectricity contains a fluororesin.
  • the fluororesin is a vinylidene fluoride polymer or a copolymer of two or more of (vinylidene fluoride, trifluoroethylene, chlorotrifluoroethylene).
  • the fluororesin is a copolymer of vinylidene fluoride and trifluoroethylene, and the molar ratio of vinylidene fluoride and trifluoroethylene contained in the copolymer is 100 is in the range of (50 to 85) :( 50 to 15).
  • the fluororesin is a copolymer of vinylidene fluoride, trifluoroethylene, and chlorotrifluoroethylene, and the vinylidene fluoride, trifluoroethylene, and chloro contained in the copolymer
  • the molar ratio of trifluoroethylene is in the range of (63 to 65) :( 27 to 29) :( 10 to 6), based on 100 as a whole.
  • the piezoelectric coating layer is a coating layer obtained by applying and drying a fluororesin solution on a substrate film.
  • the thickness of the coating layer having piezoelectricity is 0.5 ⁇ m to 20 ⁇ m.
  • the material of the base film is polyethylene terephthalate, polyethylene naphthalate, polyolefin, polycycloolefin, cycloolefin copolymer, polycarbonate, polyether sulfone, polyarylate, polyimide, polyamide, polystyrene, It is selected from at least one of polynorbornene.
  • the piezoelectric film of the present invention has a haze value of 5% or less.
  • the piezoelectric film of the present invention has a total light transmittance of 90% or more.
  • the piezoelectric layer of the present invention since the piezoelectric layer is formed by coating, the thickness of the piezoelectric layer is thinner than a piezoelectric layer made of a conventional self-supporting film. Therefore, the increase in the haze value and the decrease in the total light transmittance due to the piezoelectric layer are less than that of the piezoelectric layer made of a self-supporting film. As a result, a piezoelectric film having a small haze value and a high total light transmittance is realized.
  • the piezoelectric film of the present invention is used as a Z-coordinate detection piezoelectric film for a touch panel, it is possible to realize a touch panel having a Z-coordinate (finger pressing force) detection function with good display visibility on the back of the touch panel. it can.
  • FIG. 1 shows a first basic configuration of the piezoelectric film of the present invention.
  • the first basic configuration of the piezoelectric film of the present invention is a piezoelectric film 10 in which a base film 11 is laminated with a coating layer 12 having piezoelectricity.
  • An easy adhesion layer (not shown) may be laminated between the base film 11 and the coating layer 12 having piezoelectricity.
  • FIG. 2 shows a second basic configuration of the piezoelectric film of the present invention. Elements common to the first basic configuration are denoted by the same reference numerals.
  • a second basic configuration of the piezoelectric film of the present invention is a piezoelectric film 20 in which an undercoat layer 13 is laminated on a base film 11 and further a coating layer 12 having piezoelectricity is laminated on the undercoat layer 13. .
  • the undercoat layer 13 (or anchor coat layer) has a function of increasing the adhesion between the base film 11 and the coating layer 12 having piezoelectricity.
  • FIG. 3 shows a third basic configuration of the piezoelectric film of the present invention. Elements common to the first basic configuration are denoted by the same reference numerals.
  • a coating layer 12 having piezoelectricity is laminated on the base film 11, and at least one optical adjustment layer 14 is further laminated on the coating layer 12 having piezoelectricity.
  • This is a piezoelectric film 30.
  • the optical adjustment layer 14 (Index matching layer) (also referred to as a refractive index adjustment layer) has a function of adjusting the reflectance of the piezoelectric film 30.
  • An easy adhesion layer (not shown) may be laminated between the base film 11 and the coating layer 12 having piezoelectricity.
  • FIG. 4 shows a fourth basic configuration of the piezoelectric film of the present invention. Elements common to the first basic configuration are denoted by the same reference numerals.
  • the fourth basic configuration of the piezoelectric film of the present invention at least one first optical adjustment layer 15 is laminated on the base film 11, and further, at least one first optical adjustment layer 15 is piezoelectric.
  • the piezoelectric film 40 is formed by laminating a coating layer 12 having
  • FIG. 5 shows a fifth basic configuration of the piezoelectric film of the present invention. Elements common to the fourth basic configuration are denoted by the same reference numerals.
  • the fifth basic configuration of the piezoelectric film of the present invention at least one first optical adjustment layer 15 is laminated on the base film 11, and further, at least one first optical adjustment layer 15 is piezoelectric.
  • the piezoelectric film 50 is formed by laminating a coating layer 12 having, and further laminating at least one second optical adjustment layer 16 on the coating layer 12 having piezoelectricity.
  • FIG. 6 shows a sixth basic configuration of the piezoelectric film of the present invention. Elements common to the first basic configuration are denoted by the same reference numerals.
  • the sixth basic configuration of the piezoelectric film of the present invention is that a base film 11 is laminated with at least one anti-blocking layer 17, and further, at least one anti-blocking layer 17 has a piezoelectric coating layer 12.
  • the piezoelectric film 60 is laminated.
  • the anti-blocking layer 17 has a function of preventing the stacked or wound piezoelectric films 60 from being pressure-bonded (blocked).
  • FIG. 7 shows a seventh basic configuration of the piezoelectric film of the present invention. Elements common to the third basic configuration are denoted by the same reference numerals.
  • a coating layer 12 having piezoelectricity is laminated on one surface of the substrate film 11, and at least one optical adjustment layer 14 is further provided on the coating layer 12 having piezoelectricity.
  • the piezoelectric film 70 is laminated and has at least one anti-blocking layer 17 laminated on the other surface of the base film 11.
  • An easy adhesion layer (not shown) may be laminated between the base film 11 and the coating layer 12 having piezoelectricity.
  • FIG. 8 shows an eighth basic configuration of the piezoelectric film of the present invention. Elements common to the first basic configuration are denoted by the same reference numerals.
  • a coating layer 12 having piezoelectricity is laminated on the base film 11, and at least one transparent adhesive layer 18 is further laminated on the coating layer 12 having piezoelectricity.
  • the at least one transparent adhesive layer 18 may be at least one transparent adhesive layer.
  • An easy adhesion layer (not shown) may be laminated between the base film 11 and the coating layer 12 having piezoelectricity.
  • FIG. 9 shows a ninth basic configuration of the piezoelectric film of the present invention. Elements common to the eighth basic configuration are denoted by the same reference numerals.
  • a coating layer 12 having piezoelectricity is laminated on one surface of the substrate film 11, and at least one transparent adhesive layer 18 is formed on the other surface of the substrate film 11.
  • the at least one transparent adhesive layer 18 may be at least one transparent adhesive layer.
  • An easy adhesion layer (not shown) may be laminated between the base film 11 and the coating layer 12 having piezoelectricity.
  • the base film 11 is made of, for example, a polymer film such as polyethylene terephthalate, polyethylene naphthalate, polyolefin, polycycloolefin, cycloolefin copolymer, polycarbonate, polyether sulfone, polyarylate, polyimide, polyamide, polystyrene, and polynorbornene.
  • a polymer film such as polyethylene terephthalate, polyethylene naphthalate, polyolefin, polycycloolefin, cycloolefin copolymer, polycarbonate, polyether sulfone, polyarylate, polyimide, polyamide, polystyrene, and polynorbornene.
  • PET polyethylene terephthalate
  • the thickness of the base film 11 is preferably 10 ⁇ m to 200 ⁇ m, but is not limited thereto. However, if the thickness of the base film 11 is less than 10 ⁇ m, handling may be difficult. Moreover, when the thickness of the base film 11 exceeds 200 ⁇ m, it may be difficult to wind the piezoelectric film (10, 20, 30, 40, 50, 60, 70, 80, 90) into a roll. If the thickness of the substrate film 11 exceeds 200 ⁇ m, the piezoelectric film (10, 20, 30, 40, 50, 60, 70, 80, 90) may be too thick when mounted on a touch panel or the like. There is.
  • the material of the coating layer 12 having piezoelectricity is not particularly limited as long as the surface of the base film 11 can be coated in a thin film and the coated thin film has piezoelectricity. Absent.
  • the coating layer 12 having piezoelectricity desirably exhibits piezoelectricity without performing poling (polarization treatment), but may exhibit piezoelectricity after poling.
  • non-contact type poling and contact type poling as poling (polarization processing).
  • the coating layer 12 is polarized by subjecting the coating layer 12 to corona discharge treatment.
  • contact poling for example, the coating layer 12 is sandwiched between two metal plates, and a voltage is applied between the two metal plates to polarize the coating layer 12.
  • the coating layer 12 having piezoelectricity is made into a solution by dissolving the material of the coating layer 12 having piezoelectricity in a solvent, and is thinly applied to the surface of the base film 11 by a known coating apparatus such as a bar coater or a gravure coater. And then dried.
  • a material containing a fluororesin is preferably used as the material of the coating layer 12 having piezoelectricity.
  • the material containing a fluororesin include a vinylidene fluoride polymer, a vinylidene fluoride / trifluoroethylene copolymer, a vinylidene fluoride / trifluoroethylene / chlorotrifluoroethylene copolymer, hexafluoro Copolymer of propylene and vinylidene fluoride, copolymer of perfluorovinyl ether and vinylidene fluoride, copolymer of tetrafluoroethylene and vinylidene fluoride, copolymer of hexafluoropropylene oxide and vinylidene fluoride, hexafluoropropylene And a copolymer of tetrafluoroethylene and vinylidene fluoride.
  • the material containing a fluororesin is preferably a copolymer of vinylidene fluoride and trifluoroethylene, or a copolymer of vinylidene fluoride, trifluoroethylene, and chlorotrifluoroethylene.
  • a copolymer of vinylidene fluoride and trifluoroethylene is referred to as a binary copolymer.
  • a copolymer of vinylidene fluoride, trifluoroethylene, and chlorotrifluoroethylene is referred to as a ternary copolymer.
  • the molar ratio of vinylidene fluoride and trifluoroethylene is 100 as a whole.
  • (50 to 85): (50 to 15) is appropriate.
  • a copolymer of vinylidene fluoride, trifluoroethylene, and chlorotrifluoroethylene is used as a material for the coating layer 12 having piezoelectricity, vinylidene fluoride, trifluoroethylene
  • the molar ratio of chlorotrifluoroethylene is suitably in the range of (63 to 65) :( 27 to 29) :( 10 to 6) with 100 as a whole.
  • the thickness of the coating layer 12 having piezoelectricity is not limited, but in consideration of the optical characteristics described later, it is preferably 0.5 ⁇ m to 20 ⁇ m, more preferably 0.5 ⁇ m to 10 ⁇ m, and more preferably 0.5 ⁇ m to 5 ⁇ m. Further preferred. If the thickness of the coating layer 12 having piezoelectricity is less than 0.5 ⁇ m, the formed film may be incomplete. If the thickness of the coating layer 12 having piezoelectricity exceeds 20 ⁇ m, the optical characteristics (haze value and total light transmittance) may become inappropriate.
  • the transparent adhesive layer 18 is preferably made of an optical transparent adhesive.
  • the transparent adhesive layer 18 can be formed using a sheet of an optical transparent adhesive.
  • the transparent adhesive layer is preferably made of an optical transparent adhesive.
  • a liquid optical transparent adhesive can be applied and cured by irradiation with ultraviolet rays to form a transparent adhesive layer.
  • the refractive index of the transparent adhesive layer 18 or the transparent adhesive layer is preferably an intermediate value of the refractive indexes of the materials laminated on both sides thereof.
  • the haze value of the piezoelectric film is preferably 5% or less, more preferably 4% or less, further preferably 3% or less, and more preferably 2% or less.
  • the total light transmittance of the piezoelectric film is preferably 90% or more, more preferably 91% or more, and particularly preferably 92% or more. If the haze value of the piezoelectric film exceeds 5%, or if the total light transmittance is less than 90%, the image on the display may not be clearly visible.
  • a transparent electrode can be laminated
  • the optical adjustment layer 14 and the transparent electrode 20 are laminated on the piezoelectric film 10 of FIG.
  • the coating layer 12 having piezoelectricity in the base film 11 has a hard coat layer 22 having an anti-blocking function laminated on the surface on the tie side.
  • the transparent electrode 20 examples include indium-based composite oxides, typically indium tin composite oxide (ITO: Indium Tin Oxide), and indium zinc composite oxide, but doped with tetravalent metal ions or divalent metal ions.
  • ITO Indium Tin Oxide
  • Indium oxide In203
  • Indium composite oxides are characterized by high transmittance of 80% or more in the visible light region (380 to 780 nm) and low surface resistance per unit area (30 to 1000 ⁇ / ⁇ ).
  • the surface resistance value of the indium composite oxide is preferably 300 ⁇ / ⁇ (ohms per square) or less, and more preferably 150 ⁇ / ⁇ .
  • a transparent electrode having a low surface resistance is formed by, for example, forming an amorphous layer of an indium-based composite oxide on a cured resin layer by sputtering or vacuum evaporation, and then heat-treating it at 100 to 200 ° C. It is obtained by changing the crystalline layer to a crystalline layer.
  • the transparent electrode 20 is not limited to the above materials, and transparent conductive oxides such as tin zinc oxide, zinc oxide and fluorine-doped tin oxide, and conductive polymers such as polyethylenedioxythiophene can be used.
  • transparent conductive oxides such as tin zinc oxide, zinc oxide and fluorine-doped tin oxide, and conductive polymers such as polyethylenedioxythiophene can be used.
  • the thickness of the coating layer 12 having piezoelectricity examples are 0.5 to 10 ⁇ m, the thickness of the optical adjustment layer 14 is 80 to 160 nm, and the thickness of the transparent electrode 20 is 20 nm or more. Further, the refractive index of the coating layer 12 having piezoelectricity is 1.40 to 1.50, the refractive index of the optical adjustment layer 14 is 1.50 to 1.70, and the refractive index of the transparent electrode 20 is 1.90 to 2.50. 10 is an example. Further, the thickness of the base film 11 is set to 2 to 100 ⁇ m, and the refractive index is set to 1.50 to 1.70. By using the above thickness and refractive index, the difference in reflectance between the transparent electrode 20 and the optical adjustment layer 14 becomes 2.0% or less, and the appearance is improved.
  • the piezoelectric film 10 of Example 1 has the first basic configuration of the piezoelectric film of the present invention.
  • easy adhesion (not shown) is first formed on the surface of a substrate film 11 (polyethylene terephthalate film), and then a copolymer of vinylidene fluoride and trifluoroethylene (binary copolymer) is used. (Coupled) solution.
  • the thickness of the base film 11 (polyethylene terephthalate film) was 23 ⁇ m.
  • a vinylidene fluoride / trifluoroethylene copolymer (binary copolymer) is dissolved in methyl ethyl ketone by ultrasonic waves, and vinylidene fluoride and trifluoroethylene are dissolved.
  • a solution of this copolymer (binary copolymer) was prepared.
  • the molar ratio of vinylidene fluoride and trifluoroethylene contained in the copolymer of vinylidene fluoride and trifluoroethylene (binary copolymer) was 70/30.
  • a solution of a copolymer of vinylidene fluoride and trifluoroethylene (binary copolymer) was coated on the surface of the base film 11 (polyethylene terephthalate film) with a bar coater.
  • the base film 11 (polyethylene terephthalate film) and the undried coating layer were dried at 60 ° C. for 5 minutes to obtain a coating layer 12 having piezoelectricity.
  • the thickness of the coating layer 12 having piezoelectricity after drying was 1 ⁇ m.
  • Example 2 The piezoelectric film 10 of Example 2 has the first basic configuration of the piezoelectric film of the present invention.
  • the piezoelectric film 10 of Example 2 was produced in the same manner as the piezoelectric film 10 of Example 1 except that the thickness of the coating layer 12 having piezoelectricity after drying was 5 ⁇ m.
  • the piezoelectric film 10 of Example 3 has the first basic configuration of the piezoelectric film of the present invention.
  • the piezoelectric film 10 of Example 3 was produced in the same manner as the piezoelectric film 10 of Example 1 except that the thickness of the coating layer 12 having piezoelectricity after drying was 10 ⁇ m.
  • the piezoelectric film 10 of Example 4 has the first basic configuration of the piezoelectric film of the present invention.
  • the piezoelectric film 10 of Example 4 was produced in the same manner as the piezoelectric film 10 of Example 1 except that the thickness of the coating layer 12 having piezoelectricity after drying was 20 ⁇ m.
  • the piezoelectric film 10 of Example 5 has the first basic configuration of the piezoelectric film of the present invention.
  • the molar ratio of vinylidene fluoride and trifluoroethylene contained in the copolymer (binary copolymer) of vinylidene fluoride and trifluoroethylene is 75/25. Except for this, it was produced in the same manner as the piezoelectric film 10 of Example 1.
  • the piezoelectric film 10 of Example 6 has the first basic configuration of the piezoelectric film of the present invention.
  • the piezoelectric film 10 of Example 6 was produced in the same manner as the piezoelectric film 10 of Example 5 except that the thickness of the coating layer 12 having piezoelectricity after drying was 5 ⁇ m.
  • Example 7 The piezoelectric film 10 of Example 7 has the first basic configuration of the piezoelectric film of the present invention.
  • the piezoelectric film 10 of Example 7 was produced in the same manner as the piezoelectric film 10 of Example 5 except that the thickness of the coating layer 12 having piezoelectricity after drying was 10 ⁇ m.
  • the piezoelectric film 10 of Example 8 has the first basic configuration of the piezoelectric film of the present invention.
  • the piezoelectric film 10 of Example 8 is the piezoelectric film of Example 5 except that the thickness of the coating layer 12 having piezoelectricity after drying is 2 ⁇ m and the drying conditions are 135 ° C. and 5 minutes. It was produced in the same manner as film 10.
  • the piezoelectric film 10 of Example 9 has the first basic configuration of the piezoelectric film of the present invention.
  • the material of the coating layer 12 having piezoelectricity is a copolymer of vinylidene fluoride, trifluoroethylene, and chlorotrifluoroethylene (ternary copolymer).
  • ternary copolymer was produced in the same manner as the piezoelectric film 10 of Example 1.
  • the coating layer 12 having piezoelectricity In producing the coating layer 12 having piezoelectricity, first, a copolymer of vinylidene fluoride, trifluoroethylene, and chlorotrifluoroethylene (ternary copolymer) is dissolved in methyl isobutyl ketone at room temperature by ultrasonic waves. Then, a solution of a copolymer of vinylidene fluoride, trifluoroethylene, and chlorotrifluoroethylene (ternary copolymer) was prepared.
  • the molar ratio of vinylidene fluoride, trifluoroethylene, and chlorotrifluoroethylene contained in the copolymer of vinylidene fluoride, trifluoroethylene, and chlorotrifluoroethylene (ternary copolymer) is 64.2 / 27. 1 / 8.7.
  • a solution of a copolymer of vinylidene fluoride, trifluoroethylene, and chlorotrifluoroethylene was coated on the surface of the base film 11 (polyethylene terephthalate film) with a bar coater.
  • the base film 11 (polyethylene terephthalate film) and the undried coating layer were dried under a drying condition of 60 ° C. for 5 minutes to prepare a coating layer 12 having piezoelectricity.
  • the thickness of the coating layer 12 having piezoelectricity after drying was 1 ⁇ m.
  • the piezoelectric film 10 of Example 10 has the first basic configuration of the piezoelectric film of the present invention.
  • the piezoelectric film 10 of Example 10 was produced in the same manner as the piezoelectric film 10 of Example 9 except that the thickness of the coating layer 12 having piezoelectricity after drying was 5 ⁇ m.
  • the piezoelectric film of Comparative Example 1 is a self-supporting film (having no base film) having a thickness of 40 ⁇ m and made of a vinylidene fluoride polymer (polyvinylidene fluoride).
  • the piezoelectric film of Comparative Example 1 has a thickness of 40 ⁇ m after drying on a surface of a polyethylene terephthalate film obtained by ultrasonically dissolving a vinylidene fluoride polymer (polyvinylidene fluoride) in isobutyl ketone at room temperature. The film was coated, dried and then peeled off from the polyethylene terephthalate film.
  • Table 1 shows the configurations of the piezoelectric film examples and comparative examples of the present invention, the molar ratio and thickness of the piezoelectric coating layer, the haze value of the piezoelectric film, and the total light transmittance.
  • VDF vinylidene fluoride
  • TrFE trifluoroethylene
  • CTFE chlorotrifluoroethylene
  • PET polyethylene terephthalate
  • P () represents a copolymer. Therefore, “P (VDF-TrFE)” means “a copolymer of vinylidene fluoride and trifluoroethylene”.
  • PVDF-TrFE-CTFE means “a copolymer of vinylidene fluoride, trifluoroethylene, and chlorotrifluoroethylene”.
  • P (VDF-TrFE) / PET base film means “a copolymer of vinylidene fluoride and trifluoroethylene is coated on the surface of the base film 11 made of polyethylene terephthalate”.
  • P (VDF-TrFE-CTFE) / PET base film” is “the surface of the base film 11 made of polyethylene terephthalate is coated with a copolymer of vinylidene fluoride, trifluoroethylene, and chlorotrifluoroethylene” It means that.
  • PVDF means a polymer of vinylidene fluoride (polyvinylidene fluoride).
  • the piezoelectric films of Examples 1 to 4 have the same configuration and materials, but the thickness of the coating layer 12 having piezoelectricity is different.
  • the haze value tends to increase as the thickness of the coating layer 12 having piezoelectricity increases.
  • the haze value and the total light transmittance of the piezoelectric films of Examples 1 to 4 are all at a level with no problem.
  • the piezoelectric films of Examples 5 to 7 have the same configuration and materials, but the thickness of the coating layer 12 having piezoelectricity is different.
  • the haze value tends to slightly increase as the thickness of the coating layer 12 having piezoelectricity increases.
  • the haze values and total light transmittances of the piezoelectric films of Examples 5 to 7 are all at a level with no problem.
  • the piezoelectric film of Example 8 has the same configuration and material as the piezoelectric film of Example 5, and the thickness of the coating layer 12 is close, but the haze value is greatly different.
  • the reason why the haze value of the piezoelectric film of Example 8 is large is that the drying temperature is 135 ° C. (the drying temperature of other examples is 60 ° C.). Thus, when the drying temperature of the coating layer 12 is increased, the haze value of the piezoelectric film tends to increase.
  • the piezoelectric films of Example 9 and Example 10 have the same configuration and materials, but the thickness of the coating layer 12 having piezoelectricity is different. From Example 9 and Example 10, the haze value tends to increase as the thickness of the coating layer 12 having piezoelectricity increases. However, the haze values and total light transmittances of the piezoelectric films of Example 9 and Example 10 are all at a level with no problem.
  • the self-supporting film of the vinylidene fluoride polymer (polyvinylidene fluoride) of Comparative Example 1 has a considerably higher haze value than the piezoelectric films of Examples 1 to 10 of the present invention. Therefore, there is a high possibility that the visibility of the image on the display is lowered. However, the total light transmittance of the piezoelectric film of Comparative Example 1 is hardly different from the piezoelectric films of Examples 1 to 10 of the present invention. From Comparative Example 1, it can be seen that even if the haze value increases, the total light transmittance does not always decrease.
  • the film thickness of less than 1 ⁇ m was measured by observing the cross section using a transmission electron microscope (H-7650, manufactured by Hitachi, Ltd.). The thickness of the film or film exceeding 1 ⁇ m was measured using a film thickness meter (Digital Dial Gauge DG-205 manufactured by Peacock).
  • Example 11 to 16 Further, assuming that the transparent electrode 20 is laminated on the piezoelectric film 10 of the present application as shown in FIG. 10, the piezoelectricity when the optical adjustment layer 14 is disposed between the piezoelectric film 10 and the transparent electrode 20 is shown. The thickness and refractive index of the coating layer 12, the optical adjustment layer 14, and the transparent electrode 20 were measured.
  • the piezoelectric film 10 is the same as the above example, and is a PET film coated with a copolymer of vinylidene fluoride and trifluoroethylene.
  • the optical adjustment layer 14 may have a refractive index of 1.54, 1.62, 1.7. Since the manufacturing method differs depending on the refractive index, each refractive index will be described.
  • the refractive index is 1.54
  • a thermosetting resin having a weight ratio of 2: 2: 1 of melamine resin: alkyd resin: organosilane condensate (refractive index of light) is formed on one surface of the coating layer 12 having piezoelectricity.
  • n 1.54
  • the optical adjustment layer 14 having a thickness of 120 nm was formed.
  • an optical adjustment composition containing 47 parts by mass of ultraviolet curable resin, 57 parts by mass of zirconia oxide particles (median diameter 40 nm) and PGME on one surface of the coating layer 12 having piezoelectricity (Manufactured by JSR, “OPSTAR Z7412”, solid content: 12% by mass) was applied using a gravure coater, and immediately heated and dried at 60 ° C. for 1 minute in a windless state (less than 0.1 m / s). Then, the curing process was performed by irradiating ultraviolet rays with an integrated light amount of 250 mJ / cm 2 with a high-pressure mercury lamp.
  • the optical adjustment layer 14 having a thickness of 90, 120, or 150 nm and a refractive index of 1.62 was formed on the coating layer 12 having piezoelectricity.
  • melamine resin: alkyd resin: organosilane condensate 2: 2: 1
  • the mixing amount of the TiO 2 fine particles was adjusted so that the refractive index of the resin composition was 1.70.
  • the said resin composition was apply
  • the transparent electrode 20 was formed by sputtering indium tin oxide. The results are shown in Table 2.
  • the “first layer” is the piezoelectric coating layer 12
  • the “second layer” is the optical adjustment layer 14
  • the “third layer” is the transparent electrode 20.
  • the thickness of the coating layer 12 having piezoelectricity is 0.5 to 10 ⁇ m
  • the thickness of the optical adjustment layer 14 is 80 to 160 nm
  • the thickness of the transparent electrode 20 is 20 nm or more.
  • the refractive index of the coating layer 12 having piezoelectricity is 1.40 to 1.50
  • the refractive index of the optical adjustment layer 14 is 1.50 to 1.70
  • the refractive index of the transparent electrode 20 is 1.90 to 2.50. It is 10.
  • the difference in reflectance between the transparent electrode 20 and the optical adjustment layer 14 was 2% or less, and the appearance was good.
  • the transparent electrode 20 is etched into a desired electrode or the like as necessary.
  • the refractive index of the optical adjustment layer 14 was the portion where the transparent electrode 20 was removed by etching. Therefore, the reflectance difference was calculated
  • the optical adjustment layer 14 is obtained by diluting silica sol (Colcoat P, Colcoat P) with ethanol so that the solid content concentration becomes 2%. Is applied to one of the coating layers 12 having a property by a silica coating method, and then dried and cured at 150 ° C. for 2 minutes to form a layer having a thickness of 120 nm (SiO 2 film, light refractive index of 1.46). ) To form an optical adjustment layer 14.
  • the manufacturing method of the other configuration is the same as that of the example.
  • the transparent electrode 20 When the transparent electrode 20 is provided on the coating layer 12 having piezoelectricity, the transparent electrode 20 may be colored yellow or brown to impair the appearance.
  • the optical adjustment layer 14 As shown in Table 2, it was found that the difference in reflectance can be reduced and the appearance is not impaired. It has been found that even if a configuration in which the optical adjustment layer 14 and the transparent electrode 20 are laminated on the piezoelectric film 10 is disposed on the front surface of the display, the appearance of the display is hardly impaired.
  • the use of the piezoelectric film of the present invention is not limited, but it is particularly suitably used as a piezoelectric film for detecting the Z coordinate (pressure touched by a finger) of a touch panel.

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Abstract

This piezoelectric film 10 is provided with a laminate of a base film 11 and a coating layer 12 having piezoelectricity. The coating layer 12 having piezoelectricity contains a fluororesin. The fluororesin is a polymer of vinylidene fluoride, or a copolymer of two or more compounds selected from among vinylidene fluoride, trifluoroethylene and chlorotrifluoroethylene. The coating layer 12 having piezoelectricity is obtained by applying a solution of the fluororesin to the base film 11 and drying the solution thereon. This piezoelectric film 10 enables the achievement of a piezoelectric film that has low haze value and high total light transmittance.

Description

圧電フィルムPiezoelectric film
　本発明は圧電フィルムに関する。 The present invention relates to a piezoelectric film.
　一般に、タッチパネルでは、タッチパネルの表面にタッチする指あるいはペンの表面上の２次元位置を検出する。（以後、「指あるいはペン」を単に「指」といい、指あるいはペンのタッチパネルの表面上の２次元位置を「指のXY座標」という。）この場合、指のタッチする圧力は検出できない。（以後、指のタッチする圧力の大きさをZ軸方向にとるものと考えて、「指のZ座標」という。）即ち、指のタッチする圧力（指のZ座標）の大小にかかわらず、検出されるのは、指のタッチ位置のXY座標のみである。 Generally, a touch panel detects a two-dimensional position on the surface of a finger or pen that touches the surface of the touch panel. (Hereinafter, “finger or pen” is simply referred to as “finger”, and the two-dimensional position on the surface of the touch panel of the finger or pen is referred to as “finger XY coordinates”.) In this case, the pressure touched by the finger cannot be detected. (Hereafter, the magnitude of the pressure touched by the finger is considered to be in the Z-axis direction and is referred to as the “Z coordinate of the finger”.) That is, regardless of the magnitude of the pressure touched by the finger (Z coordinate of the finger) Only the XY coordinates of the finger touch position are detected.
　しかし、タッチパネルで使用されるアプリケーションによっては、指のタッチする圧力（指のZ座標）の識別も必要な場合がある。通常の静電容量式タッチパネルでは、指が触れることにより、触れた位置が選択されると同時に、触れた位置にある命令が実行される。静電容量式タッチパネルの感度が非常に高い場合は、指が静電容量式タッチパネルに近づいただけで（指が触れなくても）、指に最も近い位置が選択されると同時に、その位置にある命令が実行される。しかし、例えば、工作機械の操作パネル等で、誤った命令の実行が許されない場合は、選択と実行が分離されていることが望ましい。即ち、指が触れることにより（あるいは指が近づくことにより）命令が選択されるが、それだけでは命令は実行されず、次に指で圧力を加えることにより、初めて命令が実行されることが、誤動作を防止するため望ましい。 However, depending on the application used in the touch panel, it may be necessary to identify the pressure (Z coordinate of the finger) touched by the finger. In a normal capacitive touch panel, when a finger touches, a touched position is selected, and at the same time, a command at the touched position is executed. If the sensitivity of the capacitive touch panel is very high, the finger is only close to the capacitive touch panel (even if the finger does not touch it), and the position closest to the finger is selected at the same time. An instruction is executed. However, it is desirable that selection and execution are separated when, for example, an operation panel of a machine tool does not allow execution of an erroneous command. In other words, an instruction is selected by touching the finger (or by approaching the finger), but the instruction is not executed by itself, and the instruction is executed for the first time by applying pressure with the finger. Desirable to prevent.
　このような指のタッチする圧力（指のZ座標）も検出できるタッチパネルが、例えば、特許文献１（特開２０１０－２６９３８）に記載されている。特許文献１のタッチパネルでは、ポリフッ化ビニリデン－四フッ化エチレン共重合体を含有する圧電体層の両面に、透明電極が積層された積層体が用いられる。ポリフッ化ビニリデン－四フッ化エチレン共重合体を含有する圧電体層の厚さは２０μm～３００μmである。特許文献１のポリフッ化ビニリデン－四フッ化エチレン共重合体を含有する圧電体層は、キャスティング法あるいは押し出し法で製造すると記載されているため、自立したフィルム（他のフィルムに積層されていないフィルム）と考えられる。 Such a touch panel that can detect the pressure (Z coordinate of the finger) touched by a finger is described in, for example, Japanese Patent Application Laid-Open No. 2010-26938. In the touch panel of Patent Document 1, a laminate in which transparent electrodes are laminated on both sides of a piezoelectric layer containing a polyvinylidene fluoride-tetrafluoroethylene copolymer is used. The thickness of the piezoelectric layer containing the polyvinylidene fluoride-tetrafluoroethylene copolymer is 20 μm to 300 μm. Since the piezoelectric layer containing the polyvinylidene fluoride-tetrafluoroethylene copolymer of Patent Document 1 is described as being produced by a casting method or an extrusion method, a self-supporting film (a film not laminated on another film) )it is conceivable that.
　特許文献１には、ポリフッ化ビニリデン－四フッ化エチレン共重合体を含有する圧電体層のヘイズ値（曇り値）は５％～７％、全光線透過率は９５％と記載されている。この特許文献１の実施例のヘイズ値、全光線透過率は、透明電極が積層される前の、ポリフッ化ビニリデン－四フッ化エチレン共重合体を含有する圧電体層単独の値である。 Patent Document 1 describes that a piezoelectric layer containing a polyvinylidene fluoride-tetrafluoroethylene copolymer has a haze value (cloudiness value) of 5% to 7% and a total light transmittance of 95%. The haze value and the total light transmittance in the examples of Patent Document 1 are values of the piezoelectric layer alone containing the polyvinylidene fluoride-tetrafluoroethylene copolymer before the transparent electrode is laminated.
　本願発明者の実験によると、タッチパネルの背面にあるディスプレイの画像の視認性は、少なくとも、圧電フィルムのヘイズ値と全光線透過率の影響を受ける。特許文献１のポリフッ化ビニリデン－四フッ化エチレン共重合体を含有する圧電体層はヘイズ値が大きいため、タッチパネルの背面にあるディスプレイの画像の視認性が低くなるおそれがある。 According to the experiment of the present inventor, the visibility of the image on the display on the back of the touch panel is affected at least by the haze value and the total light transmittance of the piezoelectric film. Since the piezoelectric layer containing the polyvinylidene fluoride-tetrafluoroethylene copolymer of Patent Document 1 has a large haze value, the visibility of the display image on the back surface of the touch panel may be lowered.
特開２０１０－２６９３８号公報JP 2010-26938 A
　本願発明者の実験によると、タッチパネルの背面にあるディスプレイの画像の視認性の低下に対しては、全光線透過率よりもヘイズ値の方が影響が大きい。そこで本発明の目的は、ヘイズ値が小さく、更に、全光線透過率が高い圧電フィルムを実現することである。 According to the experiment of the present inventor, the haze value has a greater influence than the total light transmittance on the decrease in the visibility of the image on the back of the touch panel. Accordingly, an object of the present invention is to realize a piezoelectric film having a small haze value and a high total light transmittance.
　（１）本発明の圧電フィルムは、基材フィルムと圧電性を有するコーティング層との積層体を備える。 (1) The piezoelectric film of the present invention includes a laminate of a base film and a piezoelectric coating layer.
　（２）本発明の圧電フィルムは、基材フィルムと圧電性を有するコーティング層の間に、アンダーコート層を備える。 (2) The piezoelectric film of the present invention includes an undercoat layer between the base film and the coating layer having piezoelectricity.
　（３）本発明の圧電フィルムは、圧電性を有するコーティング層の、基材フィルムと反対側の表面に、少なくとも１層の光学調整層を備える。少なくとも１層の光学調整層とは、光学調整層が２層以上の多層膜でもよいという意味である。 (3) The piezoelectric film of the present invention includes at least one optical adjustment layer on the surface of the coating layer having piezoelectricity opposite to the base film. The at least one optical adjustment layer means that the optical adjustment layer may be a multilayer film having two or more layers.
　（４）本発明の圧電フィルムは、基材フィルムと圧電性を有するコーティング層の間に、少なくとも１層の第１の光学調整層を備える。少なくとも１層の第１の光学調整層とは、第１の光学調整層が２層以上の多層膜でもよいという意味である。 (4) The piezoelectric film of the present invention includes at least one first optical adjustment layer between the base film and the coating layer having piezoelectricity. The at least one first optical adjustment layer means that the first optical adjustment layer may be a multilayer film of two or more layers.
　（５）本発明の圧電フィルムは、圧電性を有するコーティング層の、第１の光学調整層と反対側の表面に、少なくとも１層の第２の光学調整層を備える。少なくとも１層の第２の光学調整層とは、第２の光学調整層が２層以上の多層膜でもよいという意味である。 (5) The piezoelectric film of the present invention includes at least one second optical adjustment layer on the surface of the coating layer having piezoelectricity opposite to the first optical adjustment layer. The term “at least one second optical adjustment layer” means that the second optical adjustment layer may be a multilayer film including two or more layers.
　（６）本発明の圧電フィルムは、基材フィルムと圧電性を有するコーティング層の間に、少なくとも１層のアンチブロッキング層を備える。少なくとも１層のアンチブロッキング層とは、アンチブロッキング層が２層以上の多層膜でもよいという意味である。 (6) The piezoelectric film of the present invention includes at least one anti-blocking layer between the base film and the coating layer having piezoelectricity. The at least one anti-blocking layer means that the anti-blocking layer may be a multilayer film having two or more layers.
　（７）本発明の圧電フィルムは、基材フィルムの、圧電性を有するコーティング層と反対側の表面に、少なくとも１層のアンチブロッキング層を備える。 (7) The piezoelectric film of the present invention includes at least one anti-blocking layer on the surface of the base film opposite to the piezoelectric coating layer.
　（８）本発明の圧電フィルムは、圧電性を有するコーティング層の、基材フィルムと反対側の表面に、少なくとも１層の透明粘着層を備える。少なくとも１層の透明粘着層とは、透明粘着層が２層以上の多層膜でもよいという意味である。 (8) The piezoelectric film of the present invention includes at least one transparent adhesive layer on the surface of the coating layer having piezoelectricity opposite to the base film. The at least one transparent adhesive layer means that the transparent adhesive layer may be a multilayer film having two or more layers.
　（９）本発明の圧電フィルムは、基材フィルムの、圧電性を有するコーティング層と反対側の表面に、少なくとも１層の透明粘着層を備える。 (9) The piezoelectric film of the present invention includes at least one transparent adhesive layer on the surface of the base film opposite to the piezoelectric coating layer.
　（１０）本発明の圧電フィルムにおいては、圧電性を有するコーティング層がフッ素樹脂を含む。 (10) In the piezoelectric film of the present invention, the coating layer having piezoelectricity contains a fluororesin.
　（１１）本発明の圧電フィルムにおいては、フッ素樹脂が、フッ化ビニリデンの重合体、または、（フッ化ビニリデン、トリフルオロエチレン、クロロトリフルオロエチレン）のうちの２種類以上の共重合体である。 (11) In the piezoelectric film of the present invention, the fluororesin is a vinylidene fluoride polymer or a copolymer of two or more of (vinylidene fluoride, trifluoroethylene, chlorotrifluoroethylene). .
　（１２）本発明の圧電フィルムにおいては、フッ素樹脂が、フッ化ビニリデンとトリフルオロエチレンの共重合体であって、共重合体に含まれるフッ化ビニリデンとトリフルオロエチレンのモル比が、全体を１００として、（５０～８５）：（５０～１５）の範囲である。 (12) In the piezoelectric film of the present invention, the fluororesin is a copolymer of vinylidene fluoride and trifluoroethylene, and the molar ratio of vinylidene fluoride and trifluoroethylene contained in the copolymer is 100 is in the range of (50 to 85) :( 50 to 15).
　（１３）本発明の圧電フィルムにおいては、フッ素樹脂が、フッ化ビニリデンとトリフルオロエチレンとクロロトリフルオロエチレンの共重合体であって、共重合体に含まれるフッ化ビニリデンとトリフルオロエチレンとクロロトリフルオロエチレンのモル比が、全体を１００として、（６３～６５）：（２７～２９）：（１０～６）の範囲である。 (13) In the piezoelectric film of the present invention, the fluororesin is a copolymer of vinylidene fluoride, trifluoroethylene, and chlorotrifluoroethylene, and the vinylidene fluoride, trifluoroethylene, and chloro contained in the copolymer The molar ratio of trifluoroethylene is in the range of (63 to 65) :( 27 to 29) :( 10 to 6), based on 100 as a whole.
　（１４）本発明の圧電フィルムにおいては、圧電性を有するコーティング層が、フッ素樹脂の溶液を基材フィルムに塗布および乾燥して得られるコーティング層である。 (14) In the piezoelectric film of the present invention, the piezoelectric coating layer is a coating layer obtained by applying and drying a fluororesin solution on a substrate film.
　（１５）本発明の圧電フィルムにおいては、圧電性を有するコーティング層の厚さが、０．５μm～２０μmである。 (15) In the piezoelectric film of the present invention, the thickness of the coating layer having piezoelectricity is 0.5 μm to 20 μm.
　（１６）本発明の圧電フィルムにおいては、基材フィルムの材料が、ポリエチレンテレフタレート、ポリエチレンナフタレート、ポリオレフィン、ポリシクロオレフィン、シクロオレフィンコポリマー、ポリカーボネート、ポリエーテルスルフォン、ポリアリレート、ポリイミド、ポリアミド、ポリスチレン、ポリノルボルネンの少なくとも１種から選択される。 (16) In the piezoelectric film of the present invention, the material of the base film is polyethylene terephthalate, polyethylene naphthalate, polyolefin, polycycloolefin, cycloolefin copolymer, polycarbonate, polyether sulfone, polyarylate, polyimide, polyamide, polystyrene, It is selected from at least one of polynorbornene.
　（１７）本発明の圧電フィルムはヘイズ値が５％以下である。 (17) The piezoelectric film of the present invention has a haze value of 5% or less.
　（１８）本発明の圧電フィルムは全光線透過率が９０％以上である。 (18) The piezoelectric film of the present invention has a total light transmittance of 90% or more.
　本発明の圧電フィルムにおいては、圧電体層がコーティングにより形成されるため、圧電体層の厚さが、従来の自立したフィルムからなる圧電体層より薄い。そのため、圧電体層によるヘイズ値の上昇と全光線透過率の低下が、自立したフィルムからなる圧電体層より少ない。その効果により、ヘイズ値が小さく、更に、全光線透過率が高い圧電フィルムが実現される。本発明の圧電フィルムを、タッチパネルのZ座標検出用圧電フィルムとして用いると、タッチパネルの背面にあるディスプレイの視認性が良好な、Z座標（指の押圧力）検出機能を有するタッチパネルを実現することができる。 In the piezoelectric film of the present invention, since the piezoelectric layer is formed by coating, the thickness of the piezoelectric layer is thinner than a piezoelectric layer made of a conventional self-supporting film. Therefore, the increase in the haze value and the decrease in the total light transmittance due to the piezoelectric layer are less than that of the piezoelectric layer made of a self-supporting film. As a result, a piezoelectric film having a small haze value and a high total light transmittance is realized. When the piezoelectric film of the present invention is used as a Z-coordinate detection piezoelectric film for a touch panel, it is possible to realize a touch panel having a Z-coordinate (finger pressing force) detection function with good display visibility on the back of the touch panel. it can.
本発明の圧電フィルムの第１の基本構成の模式図Schematic diagram of the first basic configuration of the piezoelectric film of the present invention 本発明の圧電フィルムの第２の基本構成の模式図Schematic diagram of the second basic configuration of the piezoelectric film of the present invention 本発明の圧電フィルムの第３の基本構成の模式図Schematic diagram of the third basic configuration of the piezoelectric film of the present invention 本発明の圧電フィルムの第４の基本構成の模式図Schematic diagram of the fourth basic configuration of the piezoelectric film of the present invention 本発明の圧電フィルムの第５の基本構成の模式図Schematic diagram of the fifth basic configuration of the piezoelectric film of the present invention 本発明の圧電フィルムの第６の基本構成の模式図Schematic diagram of the sixth basic configuration of the piezoelectric film of the present invention 本発明の圧電フィルムの第７の基本構成の模式図Schematic diagram of the seventh basic configuration of the piezoelectric film of the present invention 本発明の圧電フィルムの第８の基本構成の模式図Schematic diagram of the eighth basic configuration of the piezoelectric film of the present invention 本発明の圧電フィルムの第９の基本構成の模式図Schematic diagram of the ninth basic structure of the piezoelectric film of the present invention 本発明の圧電フィルムに透明電極を設けた構成を示す模式図The schematic diagram which shows the structure which provided the transparent electrode in the piezoelectric film of this invention
　［圧電フィルムの基本構成］
　図１に本発明の圧電フィルムの第１の基本構成を示す。本発明の圧電フィルムの第１の基本構成は、基材フィルム１１に、圧電性を有するコーティング層１２が積層されてなる圧電フィルム１０である。基材フィルム１１と圧電性を有するコーティング層１２の間に、図示しない易接着層が積層されていてもよい。 [Basic structure of piezoelectric film]
FIG. 1 shows a first basic configuration of the piezoelectric film of the present invention. The first basic configuration of the piezoelectric film of the present invention is a piezoelectric film 10 in which a base film 11 is laminated with a coating layer 12 having piezoelectricity. An easy adhesion layer (not shown) may be laminated between the base film 11 and the coating layer 12 having piezoelectricity.
　図２に本発明の圧電フィルムの第２の基本構成を示す。第１の基本構成と共通する要素には同じ符号を付す。本発明の圧電フィルムの第２の基本構成は、基材フィルム１１にアンダーコート層１３が積層され、更に、アンダーコート層１３に圧電性を有するコーティング層１２が積層されてなる圧電フィルム２０である。アンダーコート層１３（あるいはアンカーコート層）は、基材フィルム１１と圧電性を有するコーティング層１２との密着性を高くする機能がある。 FIG. 2 shows a second basic configuration of the piezoelectric film of the present invention. Elements common to the first basic configuration are denoted by the same reference numerals. A second basic configuration of the piezoelectric film of the present invention is a piezoelectric film 20 in which an undercoat layer 13 is laminated on a base film 11 and further a coating layer 12 having piezoelectricity is laminated on the undercoat layer 13. . The undercoat layer 13 (or anchor coat layer) has a function of increasing the adhesion between the base film 11 and the coating layer 12 having piezoelectricity.
　図３に本発明の圧電フィルムの第３の基本構成を示す。第１の基本構成と共通する要素には同じ符号を付す。本発明の圧電フィルムの第３の基本構成は、基材フィルム１１に圧電性を有するコーティング層１２が積層され、更に、圧電性を有するコーティング層１２に少なくとも１層の光学調整層１４が積層されてなる圧電フィルム３０である。光学調整層１４（Index matching layer）（屈折率調整層ともいう）は、圧電フィルム３０の反射率を調整する機能がある。基材フィルム１１と圧電性を有するコーティング層１２の間に、図示しない易接着層が積層されていてもよい。 FIG. 3 shows a third basic configuration of the piezoelectric film of the present invention. Elements common to the first basic configuration are denoted by the same reference numerals. In the third basic configuration of the piezoelectric film of the present invention, a coating layer 12 having piezoelectricity is laminated on the base film 11, and at least one optical adjustment layer 14 is further laminated on the coating layer 12 having piezoelectricity. This is a piezoelectric film 30. The optical adjustment layer 14 (Index matching layer) (also referred to as a refractive index adjustment layer) has a function of adjusting the reflectance of the piezoelectric film 30. An easy adhesion layer (not shown) may be laminated between the base film 11 and the coating layer 12 having piezoelectricity.
　図４に本発明の圧電フィルムの第４の基本構成を示す。第１の基本構成と共通する要素には同じ符号を付す。本発明の圧電フィルムの第４の基本構成は、基材フィルム１１に、少なくとも１層の第１の光学調整層１５が積層され、更に、少なくとも１層の第１の光学調整層１５に圧電性を有するコーティング層１２が積層されてなる圧電フィルム４０である。 FIG. 4 shows a fourth basic configuration of the piezoelectric film of the present invention. Elements common to the first basic configuration are denoted by the same reference numerals. In the fourth basic configuration of the piezoelectric film of the present invention, at least one first optical adjustment layer 15 is laminated on the base film 11, and further, at least one first optical adjustment layer 15 is piezoelectric. The piezoelectric film 40 is formed by laminating a coating layer 12 having
　図５に本発明の圧電フィルムの第５の基本構成を示す。第４の基本構成と共通する要素には同じ符号を付す。本発明の圧電フィルムの第５の基本構成は、基材フィルム１１に、少なくとも１層の第１の光学調整層１５が積層され、更に、少なくとも１層の第１の光学調整層１５に圧電性を有するコーティング層１２が積層され、更に、圧電性を有するコーティング層１２に少なくとも１層の第２の光学調整層１６が積層されてなる圧電フィルム５０である。 FIG. 5 shows a fifth basic configuration of the piezoelectric film of the present invention. Elements common to the fourth basic configuration are denoted by the same reference numerals. In the fifth basic configuration of the piezoelectric film of the present invention, at least one first optical adjustment layer 15 is laminated on the base film 11, and further, at least one first optical adjustment layer 15 is piezoelectric. The piezoelectric film 50 is formed by laminating a coating layer 12 having, and further laminating at least one second optical adjustment layer 16 on the coating layer 12 having piezoelectricity.
　図６に本発明の圧電フィルムの第６の基本構成を示す。第１の基本構成と共通する要素には同じ符号を付す。本発明の圧電フィルムの第６の基本構成は、基材フィルム１１に、少なくとも１層のアンチブロッキング層１７が積層され、更に、少なくとも１層のアンチブロッキング層１７に圧電性を有するコーティング層１２が積層されてなる圧電フィルム６０である。アンチブロッキング層１７は、積み重ねられた、あるいは、巻回された圧電フィルム６０どうしが圧着（ブロッキング）することを防止する機能がある。 FIG. 6 shows a sixth basic configuration of the piezoelectric film of the present invention. Elements common to the first basic configuration are denoted by the same reference numerals. The sixth basic configuration of the piezoelectric film of the present invention is that a base film 11 is laminated with at least one anti-blocking layer 17, and further, at least one anti-blocking layer 17 has a piezoelectric coating layer 12. The piezoelectric film 60 is laminated. The anti-blocking layer 17 has a function of preventing the stacked or wound piezoelectric films 60 from being pressure-bonded (blocked).
　図７に本発明の圧電フィルムの第７の基本構成を示す。第３の基本構成と共通する要素には同じ符号を付す。本発明の圧電フィルムの第７の基本構成は、基材フィルム１１の一面に圧電性を有するコーティング層１２が積層され、更に、圧電性を有するコーティング層１２に少なくとも１層の光学調整層１４が積層され、基材フィルム１１の他面に、少なくとも１層のアンチブロッキング層１７が積層されてなる圧電フィルム７０である。基材フィルム１１と圧電性を有するコーティング層１２の間に、図示しない易接着層が積層されていてもよい。 FIG. 7 shows a seventh basic configuration of the piezoelectric film of the present invention. Elements common to the third basic configuration are denoted by the same reference numerals. In the seventh basic configuration of the piezoelectric film of the present invention, a coating layer 12 having piezoelectricity is laminated on one surface of the substrate film 11, and at least one optical adjustment layer 14 is further provided on the coating layer 12 having piezoelectricity. The piezoelectric film 70 is laminated and has at least one anti-blocking layer 17 laminated on the other surface of the base film 11. An easy adhesion layer (not shown) may be laminated between the base film 11 and the coating layer 12 having piezoelectricity.
　図８に本発明の圧電フィルムの第８の基本構成を示す。第１の基本構成と共通する要素には同じ符号を付す。本発明の圧電フィルムの第８の基本構成は、基材フィルム１１に圧電性を有するコーティング層１２が積層され、更に、圧電性を有するコーティング層１２に少なくとも１層の透明粘着層１８が積層されてなる圧電フィルム８０である。少なくとも１層の透明粘着層１８は、少なくとも１層の透明接着層でもよい。基材フィルム１１と圧電性を有するコーティング層１２の間に、図示しない易接着層が積層されていてもよい。 FIG. 8 shows an eighth basic configuration of the piezoelectric film of the present invention. Elements common to the first basic configuration are denoted by the same reference numerals. In the eighth basic configuration of the piezoelectric film of the present invention, a coating layer 12 having piezoelectricity is laminated on the base film 11, and at least one transparent adhesive layer 18 is further laminated on the coating layer 12 having piezoelectricity. This is a piezoelectric film 80. The at least one transparent adhesive layer 18 may be at least one transparent adhesive layer. An easy adhesion layer (not shown) may be laminated between the base film 11 and the coating layer 12 having piezoelectricity.
　図９に本発明の圧電フィルムの第９の基本構成を示す。第８の基本構成と共通する要素には同じ符号を付す。本発明の圧電フィルムの第９の基本構成は、基材フィルム１１の一面に、圧電性を有するコーティング層１２が積層され、基材フィルム１１の他面に、少なくとも１層の透明粘着層１８が積層されてなる圧電フィルム９０である。少なくとも１層の透明粘着層１８は、少なくとも１層の透明接着層でもよい。基材フィルム１１と圧電性を有するコーティング層１２の間に、図示しない易接着層が積層されていてもよい。 FIG. 9 shows a ninth basic configuration of the piezoelectric film of the present invention. Elements common to the eighth basic configuration are denoted by the same reference numerals. In the ninth basic configuration of the piezoelectric film of the present invention, a coating layer 12 having piezoelectricity is laminated on one surface of the substrate film 11, and at least one transparent adhesive layer 18 is formed on the other surface of the substrate film 11. This is a piezoelectric film 90 formed by lamination. The at least one transparent adhesive layer 18 may be at least one transparent adhesive layer. An easy adhesion layer (not shown) may be laminated between the base film 11 and the coating layer 12 having piezoelectricity.
　［基材フィルム］
　基材フィルム１１は、例えば、ポリエチレンテレフタレート、ポリエチレンナフタレート、ポリオレフィン、ポリシクロオレフィン、シクロオレフィンコポリマー、ポリカーボネート、ポリエーテルスルフォン、ポリアリレート、ポリイミド、ポリアミド、ポリスチレン、ポリノルボルネンなどの高分子フィルムからなる。基材フィルム１１の材料はこれらに限定されることはないが、透明性、耐熱性、および機械特性に優れるポリエチレンテレフタレート（ＰＥＴ）が好ましい。 [Base film]
The base film 11 is made of, for example, a polymer film such as polyethylene terephthalate, polyethylene naphthalate, polyolefin, polycycloolefin, cycloolefin copolymer, polycarbonate, polyether sulfone, polyarylate, polyimide, polyamide, polystyrene, and polynorbornene. Although the material of the base film 11 is not limited to these, polyethylene terephthalate (PET) excellent in transparency, heat resistance, and mechanical properties is preferable.
　基材フィルム１１の厚さは、好ましくは、１０μm～２００μmであるが、これに限定されることはない。但し基材フィルム１１の厚さが１０μm未満であると取り扱いが困難になるおそれがある。また基材フィルム１１の厚さが２００μmを超えると、圧電フィルム（１０，２０，３０，４０，５０，６０，７０，８０，９０）を巻回してロールにするのが難しくなるおそれがある。また基材フィルム１１の厚さが２００μmを超えると、圧電フィルム（１０，２０，３０，４０，５０，６０，７０，８０，９０）をタッチパネル等に実装したときに厚さが厚くなりすぎるおそれがある。 The thickness of the base film 11 is preferably 10 μm to 200 μm, but is not limited thereto. However, if the thickness of the base film 11 is less than 10 μm, handling may be difficult. Moreover, when the thickness of the base film 11 exceeds 200 μm, it may be difficult to wind the piezoelectric film (10, 20, 30, 40, 50, 60, 70, 80, 90) into a roll. If the thickness of the substrate film 11 exceeds 200 μm, the piezoelectric film (10, 20, 30, 40, 50, 60, 70, 80, 90) may be too thick when mounted on a touch panel or the like. There is.
　［圧電性を有するコーティング層］
　圧電性を有するコーティング層１２の材料は、基材フィルム１１の表面に薄膜状にコーティングすることが可能であって、コーティング後の薄膜が圧電性を有するものであれば、特に限定されることはない。圧電性を有するコーティング層１２は、ポーリング（分極処理）を行なわなくても圧電性を示すものが望ましいが、ポーリング後に圧電性を示すものでもよい。 [Coating layer having piezoelectricity]
The material of the coating layer 12 having piezoelectricity is not particularly limited as long as the surface of the base film 11 can be coated in a thin film and the coated thin film has piezoelectricity. Absent. The coating layer 12 having piezoelectricity desirably exhibits piezoelectricity without performing poling (polarization treatment), but may exhibit piezoelectricity after poling.
　ポーリング（分極処理）として非接触式のポーリングと接触式のポーリングがある。非接触式のポーリングでは、例えば、コーティング層１２をコロナ放電処理することによりコーティング層１２を分極させる。接触式のポーリングでは、例えば、２枚の金属板でコーティング層１２を挟み、２枚の金属板の間に電圧を印加してコーティング層１２を分極させる。 There are non-contact type poling and contact type poling as poling (polarization processing). In non-contact poling, for example, the coating layer 12 is polarized by subjecting the coating layer 12 to corona discharge treatment. In contact poling, for example, the coating layer 12 is sandwiched between two metal plates, and a voltage is applied between the two metal plates to polarize the coating layer 12.
　圧電性を有するコーティング層１２は、例えば、圧電性を有するコーティング層１２の材料を溶媒に溶解させて溶液とし、バーコーターやグラビアコーターなどの既知のコーティング装置によって基材フィルム１１の表面に薄く一様にコーティングし、その後乾燥させて得られる。 For example, the coating layer 12 having piezoelectricity is made into a solution by dissolving the material of the coating layer 12 having piezoelectricity in a solvent, and is thinly applied to the surface of the base film 11 by a known coating apparatus such as a bar coater or a gravure coater. And then dried.
　［圧電性を有するコーティング層の材料］
　圧電性を有するコーティング層１２の材料は、例えば、フッ素樹脂を含む材料が好適に用いられる。フッ素樹脂を含む材料を具体的に例示すると、フッ化ビニリデンの重合体、フッ化ビニリデンとトリフルオロエチレンの共重合体、フッ化ビニリデンとトリフルオロエチレンとクロロトリフルオロエチレンの共重合体、ヘキサフルオロプロピレンとビニリデンフロライドの共重合体、パーフルオロビニルエーテルとビニリデンフロライドの共重合体、テトラフルオロエチレンとビニリデンフロライドの共重合体、ヘキサフルオロプロピレンオキシドとビニリデンフロライドの共重合体、ヘキサフルオロプロピレンとテトラフルオロエチレンとビニリデンフロライドの共重合体が挙げられる。これらのポリマーは、単独でも混合体でも用いることができる。 [Material of coating layer having piezoelectricity]
As the material of the coating layer 12 having piezoelectricity, for example, a material containing a fluororesin is preferably used. Specific examples of the material containing a fluororesin include a vinylidene fluoride polymer, a vinylidene fluoride / trifluoroethylene copolymer, a vinylidene fluoride / trifluoroethylene / chlorotrifluoroethylene copolymer, hexafluoro Copolymer of propylene and vinylidene fluoride, copolymer of perfluorovinyl ether and vinylidene fluoride, copolymer of tetrafluoroethylene and vinylidene fluoride, copolymer of hexafluoropropylene oxide and vinylidene fluoride, hexafluoropropylene And a copolymer of tetrafluoroethylene and vinylidene fluoride. These polymers can be used alone or in a mixture.
　フッ素樹脂を含む材料は、好ましくは、フッ化ビニリデンとトリフルオロエチレンの共重合体、あるいは、フッ化ビニリデンとトリフルオロエチレンとクロロトリフルオロエチレンの共重合体である。フッ化ビニリデンとトリフルオロエチレンの共重合体を２元系共重合体ということにする。フッ化ビニリデンとトリフルオロエチレンとクロロトリフルオロエチレンの共重合体を３元系共重合体ということにする。 The material containing a fluororesin is preferably a copolymer of vinylidene fluoride and trifluoroethylene, or a copolymer of vinylidene fluoride, trifluoroethylene, and chlorotrifluoroethylene. A copolymer of vinylidene fluoride and trifluoroethylene is referred to as a binary copolymer. A copolymer of vinylidene fluoride, trifluoroethylene, and chlorotrifluoroethylene is referred to as a ternary copolymer.
　フッ化ビニリデンとトリフルオロエチレンの共重合体（２元系共重合体）を、圧電性を有するコーティング層１２の材料として用いる場合は、フッ化ビニリデンとトリフルオロエチレンのモル比は、全体を１００として、（５０～８５）：（５０～１５）の範囲が適切である。 When a copolymer of vinylidene fluoride and trifluoroethylene (binary copolymer) is used as the material of the coating layer 12 having piezoelectricity, the molar ratio of vinylidene fluoride and trifluoroethylene is 100 as a whole. As a range, (50 to 85): (50 to 15) is appropriate.
　また、フッ化ビニリデンとトリフルオロエチレンとクロロトリフルオロエチレンの共重合体（３元系共重合体）を、圧電性を有するコーティング層１２の材料として用いる場合は、フッ化ビニリデンとトリフルオロエチレンとクロロトリフルオロエチレンのモル比は、全体を１００として、（６３～６５）：（２７～２９）：（１０～６）の範囲が適切である。 When a copolymer of vinylidene fluoride, trifluoroethylene, and chlorotrifluoroethylene (ternary copolymer) is used as a material for the coating layer 12 having piezoelectricity, vinylidene fluoride, trifluoroethylene, The molar ratio of chlorotrifluoroethylene is suitably in the range of (63 to 65) :( 27 to 29) :( 10 to 6) with 100 as a whole.
　［圧電性を有するコーティング層の厚さ］
　圧電性を有するコーティング層１２の厚さが限定されることはないが、後述する光学特性を考慮すると、０．５μm～２０μmが好ましく、０．５μm～１０μmがより好ましく、０．５μm～５μmがさらに好ましい。圧電性を有するコーティング層１２の厚さが０．５μm未満であると、形成された膜が不完全になるおそれがある。圧電性を有するコーティング層１２の厚さが２０μmを超えると、光学特性（ヘイズ値および全光線透過率）が不適切になるおそれがある。 [Thickness of coating layer having piezoelectricity]
The thickness of the coating layer 12 having piezoelectricity is not limited, but in consideration of the optical characteristics described later, it is preferably 0.5 μm to 20 μm, more preferably 0.5 μm to 10 μm, and more preferably 0.5 μm to 5 μm. Further preferred. If the thickness of the coating layer 12 having piezoelectricity is less than 0.5 μm, the formed film may be incomplete. If the thickness of the coating layer 12 having piezoelectricity exceeds 20 μm, the optical characteristics (haze value and total light transmittance) may become inappropriate.
　［透明粘着層］
　透明粘着層１８は光学透明粘着剤からなることが好ましい。例えば、光学透明粘着剤のシートを用いて透明粘着層１８を形成することができる。また透明接着層は光学透明接着剤からなることが好ましい。例えば、液状の光学透明接着剤を塗布し、紫外線を照射して硬化させ、透明接着層を形成することができる。透明粘着層１８あるいは透明接着層の屈折率は、その両側に積層された材料の各々の屈折率の中間的な値であることが望ましい。そのように透明粘着層１８あるいは透明接着層の屈折率を選択することにより、透明粘着層１８あるいは透明接着層と、その両側に積層された材料との界面における光の反射を抑えることができる。 [Transparent adhesive layer]
The transparent adhesive layer 18 is preferably made of an optical transparent adhesive. For example, the transparent adhesive layer 18 can be formed using a sheet of an optical transparent adhesive. The transparent adhesive layer is preferably made of an optical transparent adhesive. For example, a liquid optical transparent adhesive can be applied and cured by irradiation with ultraviolet rays to form a transparent adhesive layer. The refractive index of the transparent adhesive layer 18 or the transparent adhesive layer is preferably an intermediate value of the refractive indexes of the materials laminated on both sides thereof. Thus, by selecting the refractive index of the transparent adhesive layer 18 or the transparent adhesive layer, it is possible to suppress the reflection of light at the interface between the transparent adhesive layer 18 or the transparent adhesive layer and the material laminated on both sides thereof.
　［圧電フィルムの光学特性］
　一般に、圧電フィルムのヘイズ値が大きくなっても、光は吸収されず散乱することがあるため、全光線透過率は低下しないことがある。しかし、圧電フィルムの全光線透過率は低下しなくても、ヘイズ値が大きくなるに従って、ディスプレイ画像の視認性は低下する。そのため圧電フィルムの全光線透過率の値だけでは、ディスプレイ画像の視認性は判断できない。本願発明者の実験によると、ディスプレイ画像の視認性を確保するためには、圧電フィルムのヘイズ値は５％以下が好ましく、４％以下がより好ましく、３％以下がさらに好ましく、２％以下が特に好ましく、１％以下が特段に好ましい。また、圧電フィルムの全光線透過率は９０％以上が好ましく、９１％以上がより好ましく、９２％以上が特に好ましい。圧電フィルムのヘイズ値が５％を超える場合、あるいは、全光線透過率が９０％未満の場合、ディスプレイの画像が明瞭に視認できなくなるおそれがある。 [Optical characteristics of piezoelectric film]
In general, even if the haze value of the piezoelectric film is increased, the light may not be absorbed and may be scattered, so that the total light transmittance may not decrease. However, even if the total light transmittance of the piezoelectric film does not decrease, the visibility of the display image decreases as the haze value increases. Therefore, the visibility of the display image cannot be determined only by the value of the total light transmittance of the piezoelectric film. According to the experiment by the present inventor, in order to ensure the visibility of the display image, the haze value of the piezoelectric film is preferably 5% or less, more preferably 4% or less, further preferably 3% or less, and more preferably 2% or less. Particularly preferred is 1% or less. The total light transmittance of the piezoelectric film is preferably 90% or more, more preferably 91% or more, and particularly preferably 92% or more. If the haze value of the piezoelectric film exceeds 5%, or if the total light transmittance is less than 90%, the image on the display may not be clearly visible.
　［透明電極］
　また、本願の圧電フィルム１０に透明電極を積層し、透明電極で圧電性を有するコーティング層１２の電位の変化を検出することができる。たとえば、図１０のように、図１の圧電フィルム１０に光学調整層１４と透明電極２０を積層する。また、基材フィルム１１における圧電性を有するコーティング層１２のはタイ側の面にアンチブロッキング機能を有するハードコート層２２を積層している。 [Transparent electrode]
Moreover, a transparent electrode can be laminated | stacked on the piezoelectric film 10 of this application, and the change of the electric potential of the coating layer 12 which has piezoelectricity with a transparent electrode can be detected. For example, as shown in FIG. 10, the optical adjustment layer 14 and the transparent electrode 20 are laminated on the piezoelectric film 10 of FIG. In addition, the coating layer 12 having piezoelectricity in the base film 11 has a hard coat layer 22 having an anti-blocking function laminated on the surface on the tie side.
　透明電極２０は、インジウム系複合酸化物、代表的にはインジウムスズ複合酸化物（ＩＴＯ：Indium Tin Oxide）、インジウム亜鉛複合酸化物が挙げられるが、４価金属イオンまたは２価金属イオンがドープされた酸化インジウム（In203）が挙げられる。インジウム系複合酸化物は、可視光領域（３８０～７８０ｎｍ）で透過率が８０％以上と高く、かつ単位面積当たりの表面抵抗が低い（３０～１０００Ω／□）という特徴を有している。 Examples of the transparent electrode 20 include indium-based composite oxides, typically indium tin composite oxide (ITO: Indium Tin Oxide), and indium zinc composite oxide, but doped with tetravalent metal ions or divalent metal ions. Indium oxide (In203). Indium composite oxides are characterized by high transmittance of 80% or more in the visible light region (380 to 780 nm) and low surface resistance per unit area (30 to 1000 Ω / □).
　上記インジウム系複合酸化物の表面抵抗値は、好ましくは３００Ω／□（ohms per square）以下であり、さらに好ましくは１５０Ω／□である。表面抵抗の小さい透明電極は、たとえば、スパッタリング法または真空蒸着法により、インジウム系複合酸化物の非晶質層を硬化樹脂層上に形成した後、１００～２００℃で加熱処理して、非晶質層を結晶質層に変化することにより得られる。 The surface resistance value of the indium composite oxide is preferably 300Ω / □ (ohms per square) or less, and more preferably 150Ω / □. A transparent electrode having a low surface resistance is formed by, for example, forming an amorphous layer of an indium-based composite oxide on a cured resin layer by sputtering or vacuum evaporation, and then heat-treating it at 100 to 200 ° C. It is obtained by changing the crystalline layer to a crystalline layer.
　透明電極２０は上記の材料に限定されず、スズ亜鉛酸化物、酸化亜鉛、フッ素ドープスズ酸化物などの透明導電性酸化物、ポリエチレンジオキシチオフェンなどの導電性高分子、を用いることができる。 The transparent electrode 20 is not limited to the above materials, and transparent conductive oxides such as tin zinc oxide, zinc oxide and fluorine-doped tin oxide, and conductive polymers such as polyethylenedioxythiophene can be used.
　圧電性を有するコーティング層１２の厚さとして０．５～１０μｍ、光学調整層１４の厚さとして８０～１６０ｎｍ、透明電極２０の厚さとして２０ｎｍ以上を一例としてあげられる。また、圧電性を有するコーティング層１２の屈折率として１．４０～１．５０、光学整層１４の屈折率として１．５０～１．７０、透明電極２０の屈折率として１．９０～２．１０が一例としてあげられる。また、基材フィルム１１の厚さを２～１００μｍ、屈折率を１．５０～１．７０にする。以上の厚さと屈折率にすることで、透明電極２０と光学調整層１４の反射率差が２．０％以下になり、見栄えが良くなる。 Examples of the thickness of the coating layer 12 having piezoelectricity are 0.5 to 10 μm, the thickness of the optical adjustment layer 14 is 80 to 160 nm, and the thickness of the transparent electrode 20 is 20 nm or more. Further, the refractive index of the coating layer 12 having piezoelectricity is 1.40 to 1.50, the refractive index of the optical adjustment layer 14 is 1.50 to 1.70, and the refractive index of the transparent electrode 20 is 1.90 to 2.50. 10 is an example. Further, the thickness of the base film 11 is set to 2 to 100 μm, and the refractive index is set to 1.50 to 1.70. By using the above thickness and refractive index, the difference in reflectance between the transparent electrode 20 and the optical adjustment layer 14 becomes 2.0% or less, and the appearance is improved.
　［実施例１］
　実施例１の圧電フィルム１０は、本発明の圧電フィルムの第１の基本構成からなる。実施例１の圧電フィルム１０は、基材フィルム１１（ポリエチレンテレフタレートフィルム）の表面に、まず図示しない易接着を形成し、次にフッ化ビニリデンとトリフルオロエチレンの共重合体（２元系共重合体）の溶液をコーティングして作製された。基材フィルム１１（ポリエチレンテレフタレートフィルム）の厚さは２３μmであった。 [Example 1]
The piezoelectric film 10 of Example 1 has the first basic configuration of the piezoelectric film of the present invention. In the piezoelectric film 10 of Example 1, easy adhesion (not shown) is first formed on the surface of a substrate film 11 (polyethylene terephthalate film), and then a copolymer of vinylidene fluoride and trifluoroethylene (binary copolymer) is used. (Coupled) solution. The thickness of the base film 11 (polyethylene terephthalate film) was 23 μm.
　圧電性を有するコーティング層１２を作製するにあたり、まず、フッ化ビニリデンとトリフルオロエチレンの共重合体（２元系共重合体）を、メチルエチルケトンに超音波により溶解し、フッ化ビニリデンとトリフルオロエチレンの共重合体（２元系共重合体）の溶液を作製した。フッ化ビニリデンとトリフルオロエチレンの共重合体（２元系共重合体）に含まれる、フッ化ビニリデンとトリフルオロエチレンのモル比は、７０／３０であった。 In producing the coating layer 12 having piezoelectricity, first, a vinylidene fluoride / trifluoroethylene copolymer (binary copolymer) is dissolved in methyl ethyl ketone by ultrasonic waves, and vinylidene fluoride and trifluoroethylene are dissolved. A solution of this copolymer (binary copolymer) was prepared. The molar ratio of vinylidene fluoride and trifluoroethylene contained in the copolymer of vinylidene fluoride and trifluoroethylene (binary copolymer) was 70/30.
　次に、フッ化ビニリデンとトリフルオロエチレンの共重合体（２元系共重合体）の溶液を、バーコーターによって、基材フィルム１１（ポリエチレンテレフタレートフィルム）の表面にコーティングした。次に、基材フィルム１１（ポリエチレンテレフタレートフィルム）および未乾燥のコーティング層を、６０℃、５分の乾燥条件で乾燥して、圧電性を有するコーティング層１２を得た。乾燥後の圧電性を有するコーティング層１２の厚さは１μmであった。 Next, a solution of a copolymer of vinylidene fluoride and trifluoroethylene (binary copolymer) was coated on the surface of the base film 11 (polyethylene terephthalate film) with a bar coater. Next, the base film 11 (polyethylene terephthalate film) and the undried coating layer were dried at 60 ° C. for 5 minutes to obtain a coating layer 12 having piezoelectricity. The thickness of the coating layer 12 having piezoelectricity after drying was 1 μm.
　［実施例２］
　実施例２の圧電フィルム１０は、本発明の圧電フィルムの第１の基本構成からなる。実施例２の圧電フィルム１０は、乾燥後の圧電性を有するコーティング層１２の厚さが５μmであることを除いては、実施例１の圧電フィルム１０と同様にして作製された。 [Example 2]
The piezoelectric film 10 of Example 2 has the first basic configuration of the piezoelectric film of the present invention. The piezoelectric film 10 of Example 2 was produced in the same manner as the piezoelectric film 10 of Example 1 except that the thickness of the coating layer 12 having piezoelectricity after drying was 5 μm.
　［実施例３］
　実施例３の圧電フィルム１０は、本発明の圧電フィルムの第１の基本構成からなる。実施例３の圧電フィルム１０は、乾燥後の圧電性を有するコーティング層１２の厚さが１０μmであることを除いては、実施例１の圧電フィルム１０と同様にして作製された。 [Example 3]
The piezoelectric film 10 of Example 3 has the first basic configuration of the piezoelectric film of the present invention. The piezoelectric film 10 of Example 3 was produced in the same manner as the piezoelectric film 10 of Example 1 except that the thickness of the coating layer 12 having piezoelectricity after drying was 10 μm.
　［実施例４］
　実施例４の圧電フィルム１０は、本発明の圧電フィルムの第１の基本構成からなる。実施例４の圧電フィルム１０は、乾燥後の圧電性を有するコーティング層１２の厚さが２０μmであることを除いては、実施例１の圧電フィルム１０と同様にして作製された。 [Example 4]
The piezoelectric film 10 of Example 4 has the first basic configuration of the piezoelectric film of the present invention. The piezoelectric film 10 of Example 4 was produced in the same manner as the piezoelectric film 10 of Example 1 except that the thickness of the coating layer 12 having piezoelectricity after drying was 20 μm.
　［実施例５］
　実施例５の圧電フィルム１０は、本発明の圧電フィルムの第１の基本構成からなる。実施例５の圧電フィルム１０は、フッ化ビニリデンとトリフルオロエチレンの共重合体（２元系共重合体）に含まれる、フッ化ビニリデンとトリフルオロエチレンのモル比が７５／２５であることを除いては、実施例１の圧電フィルム１０と同様にして作製された。 [Example 5]
The piezoelectric film 10 of Example 5 has the first basic configuration of the piezoelectric film of the present invention. In the piezoelectric film 10 of Example 5, the molar ratio of vinylidene fluoride and trifluoroethylene contained in the copolymer (binary copolymer) of vinylidene fluoride and trifluoroethylene is 75/25. Except for this, it was produced in the same manner as the piezoelectric film 10 of Example 1.
　［実施例６］
　実施例６の圧電フィルム１０は、本発明の圧電フィルムの第１の基本構成からなる。実施例６の圧電フィルム１０は、乾燥後の圧電性を有するコーティング層１２の厚さが５μmであることを除いては、実施例５の圧電フィルム１０と同様にして作製された。 [Example 6]
The piezoelectric film 10 of Example 6 has the first basic configuration of the piezoelectric film of the present invention. The piezoelectric film 10 of Example 6 was produced in the same manner as the piezoelectric film 10 of Example 5 except that the thickness of the coating layer 12 having piezoelectricity after drying was 5 μm.
　［実施例７］
　実施例７の圧電フィルム１０は、本発明の圧電フィルムの第１の基本構成からなる。実施例７の圧電フィルム１０は、乾燥後の圧電性を有するコーティング層１２の厚さが１０μmであることを除いては、実施例５の圧電フィルム１０と同様にして作製された。 [Example 7]
The piezoelectric film 10 of Example 7 has the first basic configuration of the piezoelectric film of the present invention. The piezoelectric film 10 of Example 7 was produced in the same manner as the piezoelectric film 10 of Example 5 except that the thickness of the coating layer 12 having piezoelectricity after drying was 10 μm.
　［実施例８］
　実施例８の圧電フィルム１０は、本発明の圧電フィルムの第１の基本構成からなる。実施例８の圧電フィルム１０は、乾燥後の圧電性を有するコーティング層１２の厚さが２μmであること、および乾燥条件が１３５℃、５分であることを除いては、実施例５の圧電フィルム１０と同様にして作製された。 [Example 8]
The piezoelectric film 10 of Example 8 has the first basic configuration of the piezoelectric film of the present invention. The piezoelectric film 10 of Example 8 is the piezoelectric film of Example 5 except that the thickness of the coating layer 12 having piezoelectricity after drying is 2 μm and the drying conditions are 135 ° C. and 5 minutes. It was produced in the same manner as film 10.
　［実施例９］
　実施例９の圧電フィルム１０は、本発明の圧電フィルムの第１の基本構成からなる。実施例９の圧電フィルム１０は、圧電性を有するコーティング層１２の材料が、フッ化ビニリデンとトリフルオロエチレンとクロロトリフルオロエチレンの共重合体（３元系共重合体）であることを除いては、実施例１の圧電フィルム１０と同様にして作製された。 [Example 9]
The piezoelectric film 10 of Example 9 has the first basic configuration of the piezoelectric film of the present invention. In the piezoelectric film 10 of Example 9, the material of the coating layer 12 having piezoelectricity is a copolymer of vinylidene fluoride, trifluoroethylene, and chlorotrifluoroethylene (ternary copolymer). Was produced in the same manner as the piezoelectric film 10 of Example 1.
　圧電性を有するコーティング層１２を作製するにあたり、まず、フッ化ビニリデンとトリフルオロエチレンとクロロトリフルオロエチレンの共重合体（３元系共重合体）を、常温のメチルイソブチルケトンに超音波により溶解し、フッ化ビニリデンとトリフルオロエチレンとクロロトリフルオロエチレンの共重合体（３元系共重合体）の溶液を作製した。フッ化ビニリデンとトリフルオロエチレンとクロロトリフルオロエチレンの共重合体（３元系共重合体）に含まれる、フッ化ビニリデンとトリフルオロエチレンとクロロトリフルオロエチレンのモル比は、６４．２／２７．１／８．７であった。 In producing the coating layer 12 having piezoelectricity, first, a copolymer of vinylidene fluoride, trifluoroethylene, and chlorotrifluoroethylene (ternary copolymer) is dissolved in methyl isobutyl ketone at room temperature by ultrasonic waves. Then, a solution of a copolymer of vinylidene fluoride, trifluoroethylene, and chlorotrifluoroethylene (ternary copolymer) was prepared. The molar ratio of vinylidene fluoride, trifluoroethylene, and chlorotrifluoroethylene contained in the copolymer of vinylidene fluoride, trifluoroethylene, and chlorotrifluoroethylene (ternary copolymer) is 64.2 / 27. 1 / 8.7.
　次にフッ化ビニリデンとトリフルオロエチレンとクロロトリフルオロエチレンの共重合体（３元系共重合体）の溶液を、バーコーターによって、基材フィルム１１（ポリエチレンテレフタレートフィルム）の表面にコーティングした。次に、基材フィルム１１（ポリエチレンテレフタレートフィルム）および未乾燥のコーティング層を、６０℃、５分の乾燥条件で乾燥して、圧電性を有するコーティング層１２を作製した。乾燥後の圧電性を有するコーティング層１２の厚さは１μmであった。 Next, a solution of a copolymer of vinylidene fluoride, trifluoroethylene, and chlorotrifluoroethylene (ternary copolymer) was coated on the surface of the base film 11 (polyethylene terephthalate film) with a bar coater. Next, the base film 11 (polyethylene terephthalate film) and the undried coating layer were dried under a drying condition of 60 ° C. for 5 minutes to prepare a coating layer 12 having piezoelectricity. The thickness of the coating layer 12 having piezoelectricity after drying was 1 μm.
　［実施例１０］
　実施例１０の圧電フィルム１０は、本発明の圧電フィルムの第１の基本構成からなる。実施例１０の圧電フィルム１０は、乾燥後の圧電性を有するコーティング層１２の厚さが５μmであることを除いては、実施例９の圧電フィルム１０と同様にして作製された。 [Example 10]
The piezoelectric film 10 of Example 10 has the first basic configuration of the piezoelectric film of the present invention. The piezoelectric film 10 of Example 10 was produced in the same manner as the piezoelectric film 10 of Example 9 except that the thickness of the coating layer 12 having piezoelectricity after drying was 5 μm.
　［比較例１］
　比較例１の圧電フィルムは、フッ化ビニリデンの重合体（ポリフッ化ビニリデン）の、厚さ４０μmの自立したフィルム（基材フィルムを有しない）からなる。比較例１の圧電フィルムは、フッ化ビニリデンの重合体（ポリフッ化ビニリデン）を、常温のイソブチルケトンに超音波により溶解した溶液を、ポリエチレンテレフタレートフィルムの表面に、乾燥後の厚さが４０μmとなるようにコーティングし、乾燥後、ポリエチレンテレフタレートフィルムから剥がして作製された。 [Comparative Example 1]
The piezoelectric film of Comparative Example 1 is a self-supporting film (having no base film) having a thickness of 40 μm and made of a vinylidene fluoride polymer (polyvinylidene fluoride). The piezoelectric film of Comparative Example 1 has a thickness of 40 μm after drying on a surface of a polyethylene terephthalate film obtained by ultrasonically dissolving a vinylidene fluoride polymer (polyvinylidene fluoride) in isobutyl ketone at room temperature. The film was coated, dried and then peeled off from the polyethylene terephthalate film.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表１に本発明の圧電フィルムの実施例と比較例の圧電フィルムの構成、圧電性を有するコーティング層のモル比と厚さ、圧電フィルムのヘイズ値と全光線透過率を示す。表１中、VDFはフッ化ビニリデン、TrFEはトリフルオロエチレン、CTFEはクロロトリフルオロエチレン、PETはポリエチレンテレフタレートを示す。P(  )は共重合体を示す。従って、「P(VDF-TrFE)」は、「フッ化ビニリデンとトリフルオロエチレンの共重合体」という意味である。「P(VDF-TrFE-CTFE)」は、「フッ化ビニリデンとトリフルオロエチレンとクロロトリフルオロエチレンの共重合体」という意味である。「P(VDF-TrFE)/PET基材フィルム」は、「フッ化ビニリデンとトリフルオロエチレンの共重合体を、ポリエチレンテレフタレートからなる基材フィルム１１の表面にコーティングした」という意味である。「P(VDF-TrFE-CTFE)/PET基材フィルム」は、「フッ化ビニリデンとトリフルオロエチレンとクロロトリフルオロエチレンの共重合体を、ポリエチレンテレフタレートからなる基材フィルム１１の表面にコーティングした」という意味である。PVDFはフッ化ビニリデンの重合体（ポリフッ化ビニリデン）を意味する。 Table 1 shows the configurations of the piezoelectric film examples and comparative examples of the present invention, the molar ratio and thickness of the piezoelectric coating layer, the haze value of the piezoelectric film, and the total light transmittance. In Table 1, VDF is vinylidene fluoride, TrFE is trifluoroethylene, CTFE is chlorotrifluoroethylene, and PET is polyethylene terephthalate. P () represents a copolymer. Therefore, “P (VDF-TrFE)” means “a copolymer of vinylidene fluoride and trifluoroethylene”. “P (VDF-TrFE-CTFE)” means “a copolymer of vinylidene fluoride, trifluoroethylene, and chlorotrifluoroethylene”. “P (VDF-TrFE) / PET base film” means “a copolymer of vinylidene fluoride and trifluoroethylene is coated on the surface of the base film 11 made of polyethylene terephthalate”. “P (VDF-TrFE-CTFE) / PET base film” is “the surface of the base film 11 made of polyethylene terephthalate is coated with a copolymer of vinylidene fluoride, trifluoroethylene, and chlorotrifluoroethylene” It means that. PVDF means a polymer of vinylidene fluoride (polyvinylidene fluoride).
　実施例１～実施例４の圧電フィルムは、構成および材料は同じであるが、圧電性を有するコーティング層１２の厚さが異なる。実施例１～実施例４を比較すると、圧電性を有するコーティング層１２の厚さが厚くなるに従って、ヘイズ値が上昇する傾向が見られる。しかし、実施例１～実施例４の圧電フィルムのヘイズ値と全光線透過率は、全て問題の無いレベルである。 The piezoelectric films of Examples 1 to 4 have the same configuration and materials, but the thickness of the coating layer 12 having piezoelectricity is different. When Examples 1 to 4 are compared, the haze value tends to increase as the thickness of the coating layer 12 having piezoelectricity increases. However, the haze value and the total light transmittance of the piezoelectric films of Examples 1 to 4 are all at a level with no problem.
　実施例５～実施例７の圧電フィルムは、構成および材料は同じであるが、圧電性を有するコーティング層１２の厚さが異なる。実施例５～実施例７を比較すると、圧電性を有するコーティング層１２の厚さが厚くなるに従って、ヘイズ値が僅かに上昇する傾向が見られる。しかし、実施例５～実施例７の圧電フィルムのヘイズ値と全光線透過率は、全て問題の無いレベルである。 The piezoelectric films of Examples 5 to 7 have the same configuration and materials, but the thickness of the coating layer 12 having piezoelectricity is different. When Examples 5 to 7 are compared, the haze value tends to slightly increase as the thickness of the coating layer 12 having piezoelectricity increases. However, the haze values and total light transmittances of the piezoelectric films of Examples 5 to 7 are all at a level with no problem.
　実施例８の圧電フィルムは、実施例５の圧電フィルムと、構成および材料は同じであり、コーティング層１２の厚さも近いが、ヘイズ値は大きく異なる。実施例８の圧電フィルムのヘイズ値が大きい原因は、乾燥温度が１３５℃であることによる（他の実施例の乾燥温度は６０℃である）。このように、コーティング層１２の乾燥温度を高くすると、圧電フィルムのヘイズ値が大きくなる傾向がある。 The piezoelectric film of Example 8 has the same configuration and material as the piezoelectric film of Example 5, and the thickness of the coating layer 12 is close, but the haze value is greatly different. The reason why the haze value of the piezoelectric film of Example 8 is large is that the drying temperature is 135 ° C. (the drying temperature of other examples is 60 ° C.). Thus, when the drying temperature of the coating layer 12 is increased, the haze value of the piezoelectric film tends to increase.
　実施例９と実施例１０の圧電フィルムは、構成および材料は同じであるが、圧電性を有するコーティング層１２の厚さが異なる。実施例９と実施例１０から、圧電性を有するコーティング層１２の厚さが厚くなるに従って、ヘイズ値が上昇する傾向が見られる。しかし、実施例９と実施例１０の圧電フィルムのヘイズ値と全光線透過率は、全て問題の無いレベルである。 The piezoelectric films of Example 9 and Example 10 have the same configuration and materials, but the thickness of the coating layer 12 having piezoelectricity is different. From Example 9 and Example 10, the haze value tends to increase as the thickness of the coating layer 12 having piezoelectricity increases. However, the haze values and total light transmittances of the piezoelectric films of Example 9 and Example 10 are all at a level with no problem.
　比較例１のフッ化ビニリデンの重合体（ポリフッ化ビニリデン）の自立したフィルムは、本発明の実施例１～実施例１０の圧電フィルムに比べて、ヘイズ値がかなり大きい。そのため、ディスプレイの画像の視認性が低くなるおそれが大きい。しかし、比較例１の圧電フィルムの全光線透過率は、本発明の実施例１～実施例１０の圧電フィルムとほとんど違わない。比較例１から、ヘイズ値が大きくなっても、全光線透過率が低下するとは限らないことが分かる。 The self-supporting film of the vinylidene fluoride polymer (polyvinylidene fluoride) of Comparative Example 1 has a considerably higher haze value than the piezoelectric films of Examples 1 to 10 of the present invention. Therefore, there is a high possibility that the visibility of the image on the display is lowered. However, the total light transmittance of the piezoelectric film of Comparative Example 1 is hardly different from the piezoelectric films of Examples 1 to 10 of the present invention. From Comparative Example 1, it can be seen that even if the haze value increases, the total light transmittance does not always decrease.
　［測定方法］
　（厚さ）
　１μm未満の膜の厚さは、透過型電子顕微鏡（日立製作所製H-7650）を用いて、断面を観察して測定した。１μmを超える膜あるいはフィルムの厚さは、膜厚計（Peacock社製デジタルダイアルゲージDG-205）を用いて測定した。 [Measuring method]
(thickness)
The film thickness of less than 1 μm was measured by observing the cross section using a transmission electron microscope (H-7650, manufactured by Hitachi, Ltd.). The thickness of the film or film exceeding 1 μm was measured using a film thickness meter (Digital Dial Gauge DG-205 manufactured by Peacock).
　［ヘイズ値、全光線透過率］
　ヘイズ値、全光線透過率は、Direct Reading Haze Computer (Suga Test Instruments社製HGM-ZDP)を用いて測定した。 [Haze value, total light transmittance]
The haze value and total light transmittance were measured using Direct Reading Haze Computer (HGM-ZDP manufactured by Suga Test Instruments).
　[実施例１１～１６]
　また、図１０のように、本願の圧電フィルム１０に透明電極２０が積層される場合を想定して、圧電フィルム１０と透明電極２０との間に光学調整層１４を配置し場合の圧電性を有するコーティング層１２、光学調整層１４、透明電極２０の厚さおよび屈折率を測定した。圧電フィルム１０は上記実施例と同じで、PETフィルムにフッ化ビニリデンとトリフルオロエチレンの共重合体をコーティングしたものである。 [Examples 11 to 16]
Further, assuming that the transparent electrode 20 is laminated on the piezoelectric film 10 of the present application as shown in FIG. 10, the piezoelectricity when the optical adjustment layer 14 is disposed between the piezoelectric film 10 and the transparent electrode 20 is shown. The thickness and refractive index of the coating layer 12, the optical adjustment layer 14, and the transparent electrode 20 were measured. The piezoelectric film 10 is the same as the above example, and is a PET film coated with a copolymer of vinylidene fluoride and trifluoroethylene.
　光学調整層１４は下の表に２に示すように、屈折率が１．５４、１．６２、１．７の場合がある。屈折率によって製造方法が異なるので屈折率ごとに説明する。屈折率が１．５４の場合、圧電性を有するコーティング層１２の一方の面に、メラミン樹脂：アルキド樹脂：有機シラン縮合物の重量比２：２：１の熱硬化型樹脂（光の屈折率ｎ＝１.５４）により、厚さが１２０ｎｍの光学調整層１４を形成した。 As shown in Table 2 below, the optical adjustment layer 14 may have a refractive index of 1.54, 1.62, 1.7. Since the manufacturing method differs depending on the refractive index, each refractive index will be described. When the refractive index is 1.54, a thermosetting resin having a weight ratio of 2: 2: 1 of melamine resin: alkyd resin: organosilane condensate (refractive index of light) is formed on one surface of the coating layer 12 having piezoelectricity. n = 1.54), the optical adjustment layer 14 having a thickness of 120 nm was formed.
　屈折率が１．６２の場合、圧電性を有するコーティング層１２の一方の面に、紫外線硬化性樹脂４７質量部、酸化ジルコニア粒子（メジアン径４０ｎｍ）５７質量部およびＰＧＭＥを含有した光学調整組成物（ＪＳＲ社製、「オプスターＺ７４１２」、固形分１２質量％）をグラビアコーターを用いて塗布し、無風状態（０．１ｍ／ｓ未満）で直ちに６０℃で１分間加熱乾燥した。その後、高圧水銀ランプにて、積算光量２５０ｍＪ／ｃｍ２の紫外線を照射して硬化処理を実施した。この方法により、厚み９０、１２０、または１５０ｎｍで屈折率１．６２の光学調整層１４を、圧電性を有するコーティング層１２の上に形成した。 When the refractive index is 1.62, an optical adjustment composition containing 47 parts by mass of ultraviolet curable resin, 57 parts by mass of zirconia oxide particles (median diameter 40 nm) and PGME on one surface of the coating layer 12 having piezoelectricity (Manufactured by JSR, “OPSTAR Z7412”, solid content: 12% by mass) was applied using a gravure coater, and immediately heated and dried at 60 ° C. for 1 minute in a windless state (less than 0.1 m / s). Then, the curing process was performed by irradiating ultraviolet rays with an integrated light amount of 250 mJ / cm 2 with a high-pressure mercury lamp. By this method, the optical adjustment layer 14 having a thickness of 90, 120, or 150 nm and a refractive index of 1.62 was formed on the coating layer 12 having piezoelectricity.
　屈折率が１．７の場合、メラミン樹脂、アルキド樹脂及び有機シラン縮合物からなる熱硬化型樹脂（重量比で、メラミン樹脂：アルキド樹脂：有機シラン縮合物＝２：２：１）にＴｉＯ２（屈折率＝２．３５）の微粒子を混合した樹脂組成物を調製した。この際、上記樹脂組成物の屈折率が１．７０となるようにＴｉＯ２微粒子の混合量を調整した。そして、圧電性を有するコーティング層１２の上に上記樹脂組成物を塗工し、これを硬化させて、厚み１５０ｎｍの光学調整層１４（屈折率１．７０）を形成した。 When the refractive index is 1.7, a thermosetting resin composed of a melamine resin, an alkyd resin, and an organic silane condensate (by weight ratio, melamine resin: alkyd resin: organosilane condensate = 2: 2: 1) and TiO 2 A resin composition in which fine particles (refractive index = 2.35) were mixed was prepared. At this time, the mixing amount of the TiO 2 fine particles was adjusted so that the refractive index of the resin composition was 1.70. And the said resin composition was apply | coated on the coating layer 12 which has piezoelectricity, this was hardened, and the 150-nm-thick optical adjustment layer 14 (refractive index 1.70) was formed.
　また、透明電極２０は、インジウムスズ酸化物をスパッタリングによって成膜した。その結果を表２に示すが、「第１層」が圧電性を有するコーティング層１２、「第２層」が光学調整層１４、「第３層」が透明電極２０である。 The transparent electrode 20 was formed by sputtering indium tin oxide. The results are shown in Table 2. The “first layer” is the piezoelectric coating layer 12, the “second layer” is the optical adjustment layer 14, and the “third layer” is the transparent electrode 20.
　各実施例は上記のように圧電性を有するコーティング層１２の厚さが０．５～１０μｍ、光学調整層１４の厚さが８０～１６０ｎｍ、透明電極２０の厚さが２０ｎｍ以上になっている。また、圧電性を有するコーティング層１２の屈折率が１．４０～１．５０、光学調整層１４の屈折率が１．５０～１．７０、透明電極２０の屈折率が１．９０～２．１０になっている。透明電極２０と光学調整層１４の反射率差は２％以下であり、見栄えは良かった。 In each example, as described above, the thickness of the coating layer 12 having piezoelectricity is 0.5 to 10 μm, the thickness of the optical adjustment layer 14 is 80 to 160 nm, and the thickness of the transparent electrode 20 is 20 nm or more. . The refractive index of the coating layer 12 having piezoelectricity is 1.40 to 1.50, the refractive index of the optical adjustment layer 14 is 1.50 to 1.70, and the refractive index of the transparent electrode 20 is 1.90 to 2.50. It is 10. The difference in reflectance between the transparent electrode 20 and the optical adjustment layer 14 was 2% or less, and the appearance was good.
　なお、必要に応じて透明電極２０はエッチングされて所望の電極等になる。上記屈折率を求める際、光学調整層１４の屈折率は透明電極２０をエッチングによって取り除いた部分を用いた。そのため、各屈折率から空気と透明電極２０、空気と光学調整層１４の反射率を求めることで、反射率差を求めた。 Note that the transparent electrode 20 is etched into a desired electrode or the like as necessary. When obtaining the refractive index, the refractive index of the optical adjustment layer 14 was the portion where the transparent electrode 20 was removed by etching. Therefore, the reflectance difference was calculated | required by calculating | requiring the reflectance of air and the transparent electrode 20, air, and the optical adjustment layer 14 from each refractive index.
　[比較例２～３]
　実施例１１～１６に対する比較例として、光学調整層１４の無い場合（比較例２）と光学調整層１４の屈折率が１．５より小さい場合（比較例３）をおこなった。光学調整層１４が無い場合、反射率差は透明電極２０と圧電性を有するコーティング層１２の差である。反射率差が２％より大きくなり、見栄えが悪くなった。 [Comparative Examples 2-3]
As comparative examples for Examples 11 to 16, a case where the optical adjustment layer 14 was not provided (Comparative Example 2) and a case where the refractive index of the optical adjustment layer 14 was smaller than 1.5 (Comparative Example 3) were performed. When the optical adjustment layer 14 is not provided, the reflectance difference is a difference between the transparent electrode 20 and the coating layer 12 having piezoelectricity. The difference in reflectance was greater than 2% and the appearance was poor.
　なお、屈折率が１．４６の場合（比較例４）の光学調整層１４は、シリカゾル（コルコート（株）製，コルコートＰ）を、固形分濃度２％になるようにエタノールで希釈し、圧電性を有するコーティング層１２の一方の上に、シリカコート法により塗布し、その後、１５０℃で２分間乾燥、硬化させて、厚さが１２０ｎｍの層（ＳｉＯ２膜，光の屈折率１．４６）を形成して光学調整層１４とした。比較例において他の構成の製造方法は実施例と同じである。 In the case where the refractive index is 1.46 (Comparative Example 4), the optical adjustment layer 14 is obtained by diluting silica sol (Colcoat P, Colcoat P) with ethanol so that the solid content concentration becomes 2%. Is applied to one of the coating layers 12 having a property by a silica coating method, and then dried and cured at 150 ° C. for 2 minutes to form a layer having a thickness of 120 nm (SiO 2 film, light refractive index of 1.46). ) To form an optical adjustment layer 14. In the comparative example, the manufacturing method of the other configuration is the same as that of the example.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　圧電性を有するコーティング層１２の上に透明電極２０を備えることで透明電極２０によって黄色または茶色に呈色して見栄えを損ねる場合がある。上記実施例のように光学調整層１４を設け、透明電極２０、光学調整層１４、圧電性を有するコーティング層１２の厚さおよび屈折率を上述した値の範囲になるように調節することで、表２のように反射率差を小さくでき、見栄えを損ねないことがわかった。圧電フィルム１０に光学調整層１４と透明電極２０を積層した構成をディスプレイの前面に配置してもディスプレイの見栄えを損ないにくいことがわかった。 When the transparent electrode 20 is provided on the coating layer 12 having piezoelectricity, the transparent electrode 20 may be colored yellow or brown to impair the appearance. By providing the optical adjustment layer 14 as in the above embodiment, and adjusting the thickness and refractive index of the transparent electrode 20, the optical adjustment layer 14, and the coating layer 12 having piezoelectricity to be in the above-described range, As shown in Table 2, it was found that the difference in reflectance can be reduced and the appearance is not impaired. It has been found that even if a configuration in which the optical adjustment layer 14 and the transparent electrode 20 are laminated on the piezoelectric film 10 is disposed on the front surface of the display, the appearance of the display is hardly impaired.
　本発明の圧電フィルムの利用に制限はないが、特にタッチパネルのZ座標（指のタッチする圧力）を検出するための圧電フィルムとして好適に用いられる。 The use of the piezoelectric film of the present invention is not limited, but it is particularly suitably used as a piezoelectric film for detecting the Z coordinate (pressure touched by a finger) of a touch panel.
１０、２０，３０，４０，５０，６０，７０，８０，９０　　圧電フィルム
１１　　基材フィルム
１２　　圧電性を有するコーティング層
１３　　アンダーコート層
１４　　光学調整層
１５　　第１の光学調整層
１６　　第２の光学調整層
１７　　アンチブロッキング層
１８　　透明粘着層
２０　　透明電極
２２　　アンチブロッキング機能を有するハードコート層 10, 20, 30, 40, 50, 60, 70, 80, 90 Piezoelectric film 11 Base film 12 Coating layer 13 having piezoelectricity Undercoat layer 14 Optical adjustment layer 15 First optical adjustment layer 16 Second optical Adjustment layer 17 Anti-blocking layer 18 Transparent adhesive layer 20 Transparent electrode 22 Hard coat layer having an anti-blocking function

Claims (18)

  1. 　基材フィルムと圧電性を有するコーティング層との積層体を備えた圧電フィルム。 A piezoelectric film comprising a laminate of a base film and a piezoelectric coating layer.
  2. 　前記基材フィルムと前記圧電性を有するコーティング層の間に、アンダーコート層を備えた請求項１に記載の圧電フィルム。 The piezoelectric film according to claim 1, further comprising an undercoat layer between the base film and the coating layer having piezoelectricity.
  3. 　前記圧電性を有するコーティング層の、前記基材フィルムと反対側の表面に、少なくとも１層の光学調整層を備えた請求項１に記載の圧電フィルム。 2. The piezoelectric film according to claim 1, wherein at least one optical adjustment layer is provided on the surface of the coating layer having piezoelectricity opposite to the base film.
  4. 　前記基材フィルムと前記圧電性を有するコーティング層の間に、少なくとも１層の第１の光学調整層を備えた請求項１に記載の圧電フィルム。 The piezoelectric film according to claim 1, further comprising at least one first optical adjustment layer between the base film and the coating layer having piezoelectricity.
  5. 　前記圧電性を有するコーティング層の、前記第１の光学調整層と反対側の表面に、少なくとも１層の第２の光学調整層を備えた請求項４に記載の圧電フィルム。 5. The piezoelectric film according to claim 4, wherein at least one second optical adjustment layer is provided on a surface of the coating layer having piezoelectricity opposite to the first optical adjustment layer.
  6. 　前記基材フィルムと前記圧電性を有するコーティング層の間に、少なくとも１層のアンチブロッキング層を備えた請求項１に記載の圧電フィルム。 The piezoelectric film according to claim 1, further comprising at least one anti-blocking layer between the base film and the piezoelectric coating layer.
  7. 　前記基材フィルムの、前記圧電性を有するコーティング層と反対側の表面に、少なくとも１層のアンチブロッキング層を備えた請求項３に記載の圧電フィルム。 4. The piezoelectric film according to claim 3, wherein at least one anti-blocking layer is provided on a surface of the base film opposite to the coating layer having piezoelectricity.
  8. 　前記圧電性を有するコーティング層の、前記基材フィルムと反対側の表面に、少なくとも１層の透明粘着層を備えた請求項１に記載の圧電フィルム。 The piezoelectric film according to claim 1, further comprising at least one transparent adhesive layer on the surface of the coating layer having piezoelectricity opposite to the base film.
  9. 　前記基材フィルムの、前記圧電性を有するコーティング層と反対側の表面に、少なくとも１層の透明粘着層を備えた請求項１に記載の圧電フィルム。 The piezoelectric film according to claim 1, further comprising at least one transparent adhesive layer on a surface of the base film opposite to the coating layer having piezoelectricity.
  10. 　前記圧電性を有するコーティング層がフッ素樹脂を含む請求項１～９のいずれかに記載の圧電フィルム。 10. The piezoelectric film according to claim 1, wherein the piezoelectric coating layer contains a fluororesin.
  11. 　前記フッ素樹脂が、フッ化ビニリデンの重合体、または、（フッ化ビニリデン、トリフルオロエチレン、クロロトリフルオロエチレン）のうちの２種類以上の共重合体である請求項１０に記載の圧電フィルム。 The piezoelectric film according to claim 10, wherein the fluororesin is a polymer of vinylidene fluoride or a copolymer of two or more of (vinylidene fluoride, trifluoroethylene, chlorotrifluoroethylene).
  12. 　前記フッ素樹脂が、フッ化ビニリデンとトリフルオロエチレンの共重合体であって、前記共重合体に含まれる前記フッ化ビニリデンと前記トリフルオロエチレンのモル比が、全体を１００として、（５０～８５）：（５０～１５）の範囲である請求項１１に記載の圧電フィルム。 The fluororesin is a copolymer of vinylidene fluoride and trifluoroethylene, and the molar ratio of the vinylidene fluoride and the trifluoroethylene contained in the copolymer is (50 to 85 ): The piezoelectric film according to claim 11, which has a range of (50 to 15).
  13. 　前記フッ素樹脂が、フッ化ビニリデンとトリフルオロエチレンとクロロトリフルオロエチレンの共重合体であって、前記共重合体に含まれる前記フッ化ビニリデンと前記トリフルオロエチレンと前記クロロトリフルオロエチレンのモル比が、全体を１００として、（６３～６５）：（２７～２９）：（１０～６）の範囲である請求項１１に記載の圧電フィルム。 The fluororesin is a copolymer of vinylidene fluoride, trifluoroethylene, and chlorotrifluoroethylene, and the molar ratio of the vinylidene fluoride, the trifluoroethylene, and the chlorotrifluoroethylene contained in the copolymer 12. The piezoelectric film according to claim 11, wherein the total number is 100 (63 to 65): (27 to 29): (10 to 6).
  14. 　前記圧電性を有するコーティング層が、前記フッ素樹脂の溶液を前記基材フィルムに塗布および乾燥して得られるコーティング層である請求項１０～１３のいずれかに記載の圧電フィルム。 14. The piezoelectric film according to claim 10, wherein the piezoelectric coating layer is a coating layer obtained by applying and drying the fluororesin solution on the base film.
  15. 　前記圧電性を有するコーティング層の厚さが、０．５μm～２０μmである請求項１～１４のいずれかに記載の圧電フィルム。 15. The piezoelectric film according to claim 1, wherein the thickness of the piezoelectric coating layer is 0.5 μm to 20 μm.
  16. 　前記基材フィルムの材料が、ポリエチレンテレフタレート、ポリエチレンナフタレート、ポリオレフィン、ポリシクロオレフィン、シクロオレフィンコポリマー、ポリカーボネート、ポリエーテルスルフォン、ポリアリレート、ポリイミド、ポリアミド、ポリスチレン、ポリノルボルネンの少なくとも１種から選択される請求項１～１５のいずれかに記載の圧電フィルム。 The material of the base film is selected from at least one of polyethylene terephthalate, polyethylene naphthalate, polyolefin, polycycloolefin, cycloolefin copolymer, polycarbonate, polyether sulfone, polyarylate, polyimide, polyamide, polystyrene, and polynorbornene. The piezoelectric film according to any one of claims 1 to 15.
  17. 　ヘイズ値が５％以下である請求項１～１６のいずれかに記載の圧電フィルム。 The piezoelectric film according to any one of claims 1 to 16, which has a haze value of 5% or less.
  18. 　全光線透過率が９０％以上である請求項１～１７のいずれかに記載の圧電フィルム。 The piezoelectric film according to any one of claims 1 to 17, which has a total light transmittance of 90% or more.
PCT/JP2017/019979 2016-05-30 2017-05-30 Piezoelectric film WO2017209080A1 (en)

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