WO2023248696A1 - Piezoelectric film, piezoelectric element, electroacoustic transducer, and method for manufacturing piezoelectric film - Google Patents
Piezoelectric film, piezoelectric element, electroacoustic transducer, and method for manufacturing piezoelectric film Download PDFInfo
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- WO2023248696A1 WO2023248696A1 PCT/JP2023/019320 JP2023019320W WO2023248696A1 WO 2023248696 A1 WO2023248696 A1 WO 2023248696A1 JP 2023019320 W JP2023019320 W JP 2023019320W WO 2023248696 A1 WO2023248696 A1 WO 2023248696A1
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Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R17/00—Piezoelectric transducers; Electrostrictive transducers
-
- H—ELECTRICITY
- 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
- H10N30/04—Treatments to modify a piezoelectric or electrostrictive property, e.g. polarisation characteristics, vibration characteristics or mode tuning
- H10N30/045—Treatments to modify a piezoelectric or electrostrictive property, e.g. polarisation characteristics, vibration characteristics or mode tuning by polarising
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N30/00—Piezoelectric or electrostrictive devices
- H10N30/20—Piezoelectric or electrostrictive devices with electrical input and mechanical output, e.g. functioning as actuators or vibrators
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N30/00—Piezoelectric or electrostrictive devices
- H10N30/80—Constructional details
- H10N30/85—Piezoelectric or electrostrictive active materials
Definitions
- the present invention relates to a piezoelectric film, a piezoelectric element, an electroacoustic transducer, and a method for manufacturing a piezoelectric film.
- Piezoelectric elements are used for a variety of purposes as so-called exciters, which vibrate and produce sound by attaching them in contact with various objects. For example, by attaching an exciter to an image display panel, screen, etc., and causing these to vibrate, it is possible to produce sound instead of a speaker.
- piezoelectric film in which a piezoelectric layer is sandwiched between an electrode layer and a protective layer as a piezoelectric element. It has also been proposed to laminate multiple layers of piezoelectric films and use them as piezoelectric elements.
- Patent Document 1 discloses a polymer composite piezoelectric material having piezoelectric particles dispersed in a matrix containing a polymer material, and an electrode layer formed on both surfaces of the polymer composite piezoelectric material.
- a piezoelectric product whose loss tangent at a frequency of 1 kHz, determined by physical viscoelasticity measurement, has a maximum value of 0.1 or more in a temperature range exceeding 50°C and 150°C or less, and whose value at 50°C is 0.08 or more. Film is listed.
- Patent Document 1 describes a piezoelectric element in which a piezoelectric film is folded back one or more times and multiple layers of piezoelectric films are laminated.
- a piezoelectric element made by folding a piezoelectric film is used as an exciter that generates sound from the diaphragm by attaching it to a diaphragm and causing the diaphragm to vibrate.
- an external power source In order to connect an external power source to the electrode layer of such a piezoelectric element, a protrusion that protrudes in the plane direction from the laminated portion of the piezoelectric film is provided, and the external power source is connected to the electrode layer at this protrusion. That is what is being considered.
- the protruding part When voltage is applied from the connection between the electrode layer provided on the protruding part and an external power supply to drive the piezoelectric element, the protruding part generates significant heat, and in the worst case, there is a risk of thermal runaway and the inability to continuously drive the piezoelectric element. be. In order to suppress such heat generation, it is preferable that the area of the protrusion is wide.
- An object of the present invention is to solve the problems of the prior art, and to suppress the generation of noise caused by vibration in the protrusion in a piezoelectric element having a protrusion for connection to an external power source. It is an object of the present invention to provide a piezoelectric film, a piezoelectric element, an electroacoustic transducer, and a method for manufacturing a piezoelectric film, which can be used by attaching the piezoelectric film to a diaphragm and which can suppress peeling when used.
- the present invention has the following configuration.
- a piezoelectric film having a piezoelectric layer made of a polymer composite piezoelectric material containing piezoelectric particles in a matrix containing a polymer material, and electrode layers provided on both sides of the piezoelectric layer, A piezoelectric film in which a piezoelectric layer partially has an unpolarized region.
- a method for producing a piezoelectric film comprising: a piezoelectric layer made of a polymer composite piezoelectric material containing piezoelectric particles in a matrix containing a polymer material; and electrode layers provided on both sides of the piezoelectric layer.
- the polarization process is performed by applying A method for manufacturing a piezoelectric film, in which a polarized region and an unpolarized region are formed in a piezoelectric layer by regulating the region to be polarized.
- the polarization treatment is a corona poling treatment, The method for producing a piezoelectric film according to [9], wherein the electrode member is a wire-shaped corona electrode.
- the region to be polarized is regulated by making the length of the region of the wire-shaped corona electrode where corona discharge occurs shorter than the width of the piezoelectric layer, as described in [10].
- a method for manufacturing a piezoelectric film is performed by applying A method for manufacturing a piezoelectric film, in which a polarized region and an unpolarized region are formed in a piezoelectric layer by regulating the region to be polarized.
- a piezoelectric element having a protruding part for connecting to an external power source it is possible to suppress noise generation due to vibration in the protruding part, and also to prevent peeling when used by pasting it on a diaphragm.
- a piezoelectric film, a piezoelectric element, an electroacoustic transducer, and a method for manufacturing a piezoelectric film can be provided.
- FIG. 1 is a perspective view schematically showing an example of a piezoelectric element of the present invention having a piezoelectric film of the present invention.
- FIG. 2 is a side view of the piezoelectric element shown in FIG. 1.
- FIG. FIG. 2 is a perspective view showing a state before the piezoelectric film shown in FIG. 1 is folded back.
- 4 is a diagram for explaining polarized regions and unpolarized regions of the piezoelectric film shown in FIG. 3.
- FIG. 2 is a diagram schematically showing an example of an electroacoustic transducer of the present invention having the piezoelectric element shown in FIG. 1.
- FIG. It is a perspective view which shows typically another example of the piezoelectric film of this invention.
- FIG. 8 is a diagram schematically showing an example of the electroacoustic transducer of the present invention having the piezoelectric film shown in FIG. 7.
- FIG. FIG. 2 is a conceptual diagram for explaining an example of a method for manufacturing a piezoelectric film.
- FIG. 2 is a conceptual diagram for explaining an example of a method for manufacturing a piezoelectric film.
- FIG. 2 is a conceptual diagram for explaining an example of a method for manufacturing a piezoelectric film.
- FIG. 3 is a conceptual diagram for explaining an example of a polarization treatment process.
- FIG. 7 is a conceptual diagram for explaining another example of the polarization treatment process.
- FIG. 2 is a conceptual diagram for explaining an example of a method for manufacturing a piezoelectric film.
- the piezoelectric film of the present invention is A piezoelectric film having a piezoelectric layer made of a polymer composite piezoelectric material containing piezoelectric particles in a matrix containing a polymer material, and electrode layers provided on both sides of the piezoelectric layer,
- the piezoelectric film is a piezoelectric film in which the piezoelectric layer partially has an unpolarized region.
- the piezoelectric element of the present invention is a piezoelectric element formed by laminating a plurality of layers of piezoelectric films by folding the piezoelectric film one or more times,
- the piezoelectric film has a laminated part where two or more layers overlap and a protrusion part that protrudes from the laminated part,
- the protruding portion has a connecting portion for connecting the electrode layer and an external power source, It is a piezoelectric element in which unpolarized regions are present in the protrusions.
- FIG. 1 is a perspective view schematically showing an example of a piezoelectric element of the present invention having a piezoelectric film of the present invention.
- FIG. 2 shows a side view of the piezoelectric element of FIG. 1.
- FIG. 3 shows a perspective view of the piezoelectric film of the piezoelectric element of FIG. 1 before it is folded back. Note that the plan view is a view seen from the lamination direction in which a plurality of piezoelectric films 10 are laminated.
- the piezoelectric element 50 shown in FIGS. 1 and 2 is made by laminating three layers of piezoelectric films 10a by folding back one rectangular piezoelectric film 10a twice in one direction. That is, this piezoelectric element 50 is a laminated piezoelectric element in which three layers of piezoelectric films 10a are laminated. Although omitted in FIG. 1 to simplify the drawing and clearly show the structure of the piezoelectric element 50, the piezoelectric film 10a has electrode layers on both sides of the piezoelectric layer 20, and covers both electrode layers. It has a protective layer. Further, in FIG. 3, illustration of the protective layer is omitted. Furthermore, in the following description, the direction in which the piezoelectric film 10a is folded back (the left-right direction in FIG. 1) is referred to as the folding direction.
- the piezoelectric film 10a includes a piezoelectric layer 20 made of a polymer composite piezoelectric material containing piezoelectric particles 36 in a matrix 34 containing a polymer material, and a piezoelectric layer 20 provided on both sides of the piezoelectric layer 20. (the first electrode layer 24 and the second electrode layer 26). Moreover, the piezoelectric film 10a has a protective layer (first protective layer 28 and second protective layer 30) provided on each electrode layer.
- the piezoelectric layer 20 is polarized in the thickness direction.
- the piezoelectric particles 36 in the piezoelectric layer 20 expand and contract in the polarization direction according to the applied voltage.
- the piezoelectric film 10a contracts in the thickness direction.
- the piezoelectric film 10a also expands and contracts in the plane direction due to the Poisson ratio. Thereby, the piezoelectric film 10a can exhibit piezoelectric performance.
- Each component of the piezoelectric film will be detailed later.
- the piezoelectric element 50 can be formed by laminating a plurality of layers of piezoelectric films.
- the piezoelectric element 50 has a laminated part 11a in which three layers of piezoelectric films 10a overlap in plan view, and a protrusion part 11b that protrudes outward in the plane direction from the laminated part 11a. That is, in the piezoelectric element 50, when one piezoelectric film 10a is folded twice, the two layers from the bottom side in FIG.
- the protruding portion 11b is It was established.
- the piezoelectric element 50 is made by folding back the piezoelectric film 10a twice and laminating three layers of piezoelectric films 10a, but the piezoelectric element is not limited to this. It may be one in which piezoelectric films are laminated, or one in which four or more layers of piezoelectric films are laminated.
- Adjacent layers of the piezoelectric film 10a in the laminated portion 11a are adhered to each other by an adhesive layer 14.
- an adhesive layer 14 for adhering piezoelectric films to each other various known adhesive layers can be used as long as they can adhere adjacent piezoelectric films 10 to each other.
- the adhesive layer 14 the same material as the adhesive layer for pasting the diaphragm and the piezoelectric element, which will be described later, can be used.
- the laminated portion 11a is a region where two or more layers of piezoelectric films overlap when viewed in plan, that is, when the piezoelectric element is viewed from above (or from below) in FIG. That is, as shown in FIGS. 1 and 2, a region where three layers of the piezoelectric film 10a overlap is the laminated portion 11a.
- the protruding portion 11b is a region that protrudes from the laminated portion 11a in the surface direction, and is a region that does not overlap with other layers in plan view.
- the right end of the uppermost layer in the figures is the protrusion 11b.
- the protrusion 11b includes a conductive wire 40 and a conductive wire 42 for connecting the first electrode layer 24 and the second electrode layer 26 (hereinafter also collectively referred to as electrode layers) and an external electrode. is formed.
- the piezoelectric film 10a has a protective layer (the first protective layer 28 and the second protective layer 30)
- the protective layer (the first protective layer 28 and the second protective layer 30) in the region of the protrusion 11b is A through hole is formed in the layer 30) to expose the electrode layer, and a connecting portion is provided to be electrically connected to the conductive wire 40 and the conductive wire 42, respectively.
- known methods such as laser processing, dissolution and removal using a solvent, and mechanical processing such as mechanical polishing may be used. .
- the connecting portion is connected to a conductive wire filled with a known conductive material such as a conductive metal paste such as a silver paste, a conductive carbon paste, or a conductive nano ink and connected to an external power source.
- a known conductive material such as a conductive metal paste such as a silver paste, a conductive carbon paste, or a conductive nano ink
- a conductive metal paste such as a silver paste, a conductive carbon paste, or a conductive nano ink
- the piezoelectric element 50 of the present invention is driven by applying a voltage to the electrode layer using an external power source via the connection part provided on the protrusion 11b.
- the piezoelectric element 50 expands and contracts in the plane direction, bends the diaphragm to which the piezoelectric element 50 is attached, and as a result vibrates the diaphragm to generate sound.
- the diaphragm vibrates according to the magnitude of the driving voltage applied to the piezoelectric element 50, and generates sound according to the driving voltage applied to the piezoelectric element 50. That is, the piezoelectric element 50 can be used as an exciter.
- the piezoelectric layer 20 of the protrusion 11b has an unpolarized region 20b.
- the piezoelectric element 50 has an unpolarized region 20b in which the entire piezoelectric layer 20 of the protrusion 11b is not polarized.
- the entire area of the piezoelectric layer 20 of the laminated portion 11a other than the protruding portion 11b is a polarized region 20a polarized in the thickness direction.
- the piezoelectric film 10a of the piezoelectric element 50 in other words, in the state in which the folded piezoelectric film 10a is unfolded, the piezoelectric film 10a is partially attached to the piezoelectric layer 20, as shown in FIG. It has an unpolarized region 20b that is not polarized, and the other region (the region that becomes the laminated portion 11a) is a polarized region 20a that is polarized in the thickness direction.
- FIG. 4 shows a perspective view of the piezoelectric film 10a with the second electrode layer 26 omitted for explanation.
- the piezoelectric film 10a has a rectangular shape and has an unpolarized region 20b in a region of a predetermined width along one edge. That is, the unpolarized region 20b exists at the outer edge of the piezoelectric film 10a.
- the piezoelectric layer 20 is polarized in the thickness direction in the region sandwiched between the pair of electrodes (the first electrode layer 24 and the second electrode layer 26). It has a polarized region 20a and an unpolarized region 20b. That is, the electrode layer sandwiching the polarized region 20a and the electrode layer sandwiching the unpolarized region 20b are integral.
- the protrusion 11b with a connecting part for connecting to an external power source, the laminated part 11a and A voltage can be appropriately applied to the polarized region 20a.
- the piezoelectric layer 20 (piezoelectric film 10a) is polarized in the thickness direction, thereby exhibiting piezoelectric performance that expands and contracts in accordance with the applied voltage. Therefore, when a voltage is applied to the electrode layer (electrode pair) of the laminated portion 11a in which the piezoelectric layer 20 is polarized through the connection portion of the protruding portion 11b, the piezoelectric element 50 exhibits piezoelectric performance. Stretch and contract in the plane direction.
- the unpolarized region 20b in which the piezoelectric layer 20 is not polarized does not expand or contract even when a voltage is applied to the electrode layer of the protrusion 11b. Therefore, vibration does not occur in the protruding portion 11b, and generation of unnecessary sound (noise) can be suppressed.
- the entire area of the piezoelectric layer 20 of the protrusion 11b is configured as the unpolarized region 20b, but the present invention is not limited to this, and at least one portion of the piezoelectric layer 20 of the protrusion 11b is It suffices if the portion is the unpolarized region 20b. From the viewpoint of suppressing unnecessary sound (noise) caused by the protrusion 11b, it is preferable that the entire area of the piezoelectric layer 20 of the protrusion 11b is the unpolarized region 20b.
- the entire region other than the protruding portion 11b of the piezoelectric layer 20 (the region that becomes the laminated portion 11a) is configured to be the polarized region 20a, but the structure is not limited to this, and the laminated An unpolarized region 20b may be included in a part of the region that becomes part 11a. From the viewpoint of appropriately driving the piezoelectric element 50 and obtaining high piezoelectric performance, it is preferable that the entire region that becomes the laminated portion 11a is the polarized region 20a.
- the polarized region and the unpolarized region can be measured as follows.
- a ferroelectric material such as PZT is used as the piezoelectric particles in a piezoelectric film that uses a polymer composite piezoelectric material formed by dispersing piezoelectric particles in a matrix containing a polymer material as a piezoelectric layer.
- the crystal structure of this ferroelectric material is divided into many domains with different directions of spontaneous polarization, and in this state, the spontaneous polarization of each domain and the resulting piezoelectric effect cancel each other out. No piezoelectricity is observed as a whole.
- piezoelectric films it is possible to align the direction of spontaneous polarization in each domain by applying electrical polarization processing such as poling to the piezoelectric layer and applying an external electric field of a certain value or more. It is being said.
- the polarized piezoelectric particles exhibit a piezoelectric effect in response to an external electric field.
- the piezoelectric film expands and contracts in the plane direction in response to the applied voltage, and vibrates in a direction perpendicular to the plane, thereby converting vibration (sound) and electrical signals.
- X-ray diffraction is used to analyze the crystal structure of such piezoelectric layers (piezoelectric particles), and XRD is used to examine how atoms are arranged inside the crystal. This makes it possible to distinguish between polarized regions and unpolarized regions.
- the polymer composite piezoelectric material that is the piezoelectric layer 20 is evaluated by X-ray diffraction method (XRD), the (002) plane peak intensity (c domain) derived from the piezoelectric particles and the (200 ) If the ratio ⁇ to the plane peak intensity (a domain) is 1 or more, it is regarded as a polarized region, and if it is less than 1, it is regarded as an unpolarized region.
- the X-ray irradiation area in this XRD evaluation was 1 cm square, and the evaluation was performed two-dimensionally with a 1 mm interval in the X and Y directions within the plane of the piezoelectric layer, and the polarized and unpolarized regions were measured. can do.
- the (002) plane peak intensity is the tetragonal peak around 43.5° in the XRD pattern obtained by XRD analysis ( ⁇ -2 ⁇ method), and the (200) plane peak intensity is the In the XRD pattern obtained by analysis, this is a tetragonal peak around 45°.
- the (002) plane peak intensity corresponds to the proportion of domains (c domains) whose polarization axis is perpendicular to the X-ray diffraction plane (in-plane direction of the piezoelectric film), and the (200) plane peak intensity is It corresponds to the proportion of domains (a-domains) whose polarization axes are parallel to the X-ray diffraction plane.
- polarization processing of a piezoelectric body is an act of inverting the polarization of the c domain (180° domain switching), but this 180° domain switching itself cannot be determined by XRD analysis.
- 180° domain switching disappearance of the 180° domain wall
- the 90° domain wall which was previously clamped to the 180° domain wall, can now move easily and A so-called 90° domain motion (a-domain ⁇ c-domain) occurs in response to the stimulus.
- XRD analysis can be performed using an X-ray diffraction device (X'Pert PRO manufactured by PANalytical) or the like.
- FIG. 5 schematically shows an example of an electroacoustic transducer having the piezoelectric element 50 described above.
- the electroacoustic transducer 100a shown in FIG. 5 includes a piezoelectric element 50 and a diaphragm 102.
- the piezoelectric element 50 has the same configuration as the example shown in FIG. 1 and the like.
- the piezoelectric element 50 and the diaphragm 102 are attached to each other with an adhesive layer (not shown).
- the piezoelectric film 10a of the piezoelectric element 50 expands and contracts in the plane direction, and due to the expansion and contraction of the piezoelectric film 10a, the piezoelectric element 50 expands and contracts.
- the expansion and contraction of the piezoelectric element 50 in the plane direction causes the diaphragm 102 to bend, and as a result, the diaphragm 102 vibrates in the thickness direction. Due to this vibration in the thickness direction, the diaphragm 102 generates sound.
- the diaphragm 102 vibrates according to the magnitude of the driving voltage applied to the piezoelectric film 10a, and generates sound according to the driving voltage applied to the piezoelectric film 10a.
- the diaphragm 102 preferably has flexibility.
- having flexibility is synonymous with having flexibility in a general interpretation, and indicates that it is possible to bend and bend. , indicating that it can be bent and stretched without breaking or damage.
- the diaphragm 102 is not particularly limited as long as it is preferably flexible, and various sheet-like materials (plate-like materials, films) can be used.
- sheet-like materials plate-like materials, films
- Examples include polyethylene terephthalate (PET), polypropylene (PP), polystyrene (PS), polycarbonate (PC), polyphenylene sulfite (PPS), polymethyl methacrylate (PMMA), polyetherimide (PEI), polyimide (PI), Resin films made of polyethylene naphthalate (PEN), triacetyl cellulose (TAC), cyclic olefin resins, etc., foamed polystyrene, foamed plastics made of foamed styrene, foamed polyethylene, etc., and corrugated paperboard on one or both sides. Examples include various corrugated cardboard materials made by gluing paperboard.
- the diaphragm 102 may be an organic electroluminescence (OLED) display, a liquid crystal display, or a microLED (Light Emitting Diode) display, as long as it has flexibility. , and display devices such as inorganic electroluminescent displays can also be suitably used.
- OLED organic electroluminescence
- liquid crystal display or a microLED (Light Emitting Diode) display
- microLED Light Emitting Diode
- display devices such as inorganic electroluminescent displays can also be suitably used.
- the electrode layer of the piezoelectric element 50 (piezoelectric film 10a) and the diaphragm 102 are not electrically connected. If the electrode layer of the piezoelectric element 50 and the diaphragm 102 are electrically connected, troubles such as short circuits may occur. Therefore, by configuring the electrode layer of the piezoelectric element 50 and the diaphragm 102 to be not electrically connected, the risk of occurrence of failure can be reduced.
- the adhesive layer has fluidity when it is pasted and then becomes solid.
- a layer made of adhesive is a gel-like (rubber-like) soft solid when it is pasted and remains in a gel-like state after that. It may be a layer made of an adhesive that does not change, or a layer made of a material that has characteristics of both an adhesive and a pressure-sensitive adhesive.
- the diaphragm 102 is bent and vibrated to generate sound. Therefore, in the electroacoustic transducer 100, it is preferable that the expansion and contraction of the piezoelectric element 50 be directly transmitted to the diaphragm 102. If a viscous substance that dampens vibration exists between the diaphragm 102 and the piezoelectric element 50, the efficiency of transmitting the energy of the expansion and contraction of the piezoelectric element 50 to the diaphragm 102 will decrease, resulting in electroacoustic conversion. As a result, the driving efficiency of the device 100 decreases.
- the adhesive layer that adheres the diaphragm and the piezoelectric element (piezoelectric film) to the diaphragm and the piezoelectric element (piezoelectric film) is an adhesive layer that is made of an adhesive that provides a solid and harder adhesive layer than an adhesive layer that is made of an adhesive.
- it is a layer of agent.
- More preferable adhesive layers include, specifically, adhesive layers made of thermoplastic adhesives such as polyester adhesives and styrene-butadiene rubber (SBR) adhesives. Adhesion, unlike adhesion, is useful when a high bonding temperature is required.
- thermoplastic adhesives are suitable because they have "relatively low temperature, short time, and strong adhesion.”
- the thickness of the adhesive layer there is no limit to the thickness of the adhesive layer, and a thickness that provides sufficient adhesive strength (adhesive strength, adhesive strength) may be appropriately set depending on the material of the adhesive layer.
- the thinner the adhesive layer is the higher the transmission effect of the elastic energy (vibration energy) of the piezoelectric element 50 to the diaphragm 102 can be, and the higher the energy efficiency can be.
- the adhesive layer is thick and rigid, expansion and contraction of the piezoelectric element 50 may be restricted. Considering this point, it is preferable that the adhesive layer be thinner.
- the thickness of the adhesive layer after attachment is preferably 0.1 to 50 ⁇ m, more preferably 0.1 to 30 ⁇ m, even more preferably 0.1 to 10 ⁇ m.
- the adhesive layer is provided as a preferred embodiment and is not an essential component. Therefore, the electroacoustic transducer 100 may not have an adhesive layer, and the diaphragm 102 and the piezoelectric element 50 may be fixed using known crimping means, fastening means, fixing means, or the like.
- the piezoelectric element 50 has a rectangular shape in plan view, the four corners may be fastened with members such as bolts and nuts to form an electroacoustic transducer, or the four corners and the center may be connected with bolts.
- the electroacoustic transducer may be configured by fastening with a member such as a nut.
- the piezoelectric element 50 when a driving voltage is applied from the power source, the piezoelectric element 50 expands and contracts independently with respect to the diaphragm 102, and in some cases, only the piezoelectric element 50 is bent, causing the piezoelectric element 50 to expansion and contraction is not transmitted to the diaphragm 102. In this way, when the piezoelectric element 50 expands and contracts independently with respect to the diaphragm 102, the vibration efficiency of the diaphragm 102 caused by the piezoelectric element 50 decreases. There is a possibility that the diaphragm 102 cannot be vibrated sufficiently. Taking this point into consideration, it is preferable that the diaphragm 102 and the piezoelectric element 50 be attached using an adhesive layer.
- the piezoelectric film 10b shown in FIG. 6 is a single rectangular piezoelectric film.
- illustration of the protective layer is omitted in order to simplify the drawing and clearly show the configuration of the piezoelectric element 50.
- the piezoelectric film 10b shown in FIG. 6 has the same configuration as the piezoelectric film 10a shown in FIG. 3, except that the arrangement of the unpolarized regions 20b in the piezoelectric layer 20 is different.
- two regions of a predetermined width along the opposing edges (left and right edges in the figure) of the piezoelectric layer 20 are unpolarized regions 20b, and the other regions are unpolarized regions 20b.
- the region that is, the center region in the left-right direction in the figure is a polarized region 20a polarized in the thickness direction. That is, the unpolarized region 20b exists at the outer edge of the piezoelectric film 10b.
- such a piezoelectric film 10b can be attached to a diaphragm 102 and used as an electroacoustic transducer 100b.
- the electroacoustic transducer 100b having the piezoelectric film 10b of the present invention has an unpolarized region 20b at the outer edge of the piezoelectric film 10b. Therefore, as shown by arrows in FIG. 7, the piezoelectric film 10b expands and contracts (vibrates) in the center region of the piezoelectric film 10b, but does not expand and contract (vibrates) in the regions at both ends. Therefore, it is possible to reduce the stress concentrated at the end of the bonding surface between the piezoelectric film 10b and the diaphragm 102, and it is possible to suppress the occurrence of peeling from the end.
- the width of the unpolarized region in the piezoelectric film is preferably 1 mm or more, more preferably 3 mm or more, and 10 mm or more. The above is more preferable.
- the width of the unpolarized region in the piezoelectric film is preferably 10% or less of the width of the piezoelectric film, more preferably 5% or less, and even more preferably 3% or less.
- the piezoelectric film 10b has two unpolarized regions 20b along two opposing edges among the four edges in a plan view, but the present invention is not limited to this.
- the configuration may include the unpolarized region 20b along one or three edges, or the unpolarized region 20b may be provided along the four edges, that is, over the entire outer edge of the piezoelectric film 10b. may have.
- the configuration is such that the unpolarized region 20b is provided in the entire area along the edge of the piezoelectric film 10b, but the structure is not limited to this, and a part of the area along the edge of the piezoelectric film 10b is used. It is also possible to have an unpolarized region 20b in the region.
- the piezoelectric film 10b may have an unpolarized region 20b at at least one of its four corners in a plan view.
- the single-layer piezoelectric film 10b is attached to the diaphragm 102, but the present invention is not limited to this.
- a configuration including a polarized region 20b may also be used.
- the piezoelectric element 50 has an unpolarized region 20b of a predetermined width along the right edge of the piezoelectric film 10a on the diaphragm 102 side (lower side in the figure). By doing so, stress concentration can be prevented from occurring at the end portions of the bonding surfaces between the piezoelectric element 50 and the diaphragm 102, and peeling from the end portions can be suppressed.
- the electrode layer of the piezoelectric film 10b and the diaphragm 102 are not electrically connected.
- the piezoelectric film 10b has an unpolarized region 20b at the outer edge thereof, but the present invention is not limited thereto.
- an unpolarized region 20b may be provided in a region along the right edge in the figure of the adhesion surface. In this case, before the piezoelectric film 10a of the piezoelectric element 50 is folded back, the unpolarized region 20b is formed in a region other than the outer edge of the piezoelectric film 10a.
- the piezoelectric films 10a to 10b are also collectively referred to as the piezoelectric film 10 unless it is necessary to distinguish them.
- FIG. 8 shows a part of the piezoelectric film 10 in an enlarged manner.
- the piezoelectric film 10 shown in FIG. A second protective layer 30 laminated on the surface opposite to the body layer 20 , a first electrode layer 24 laminated on the other surface of the piezoelectric layer 20 , and a layer opposite to the piezoelectric layer 20 of the first electrode layer 24 A first protective layer 28 is laminated on the side surface. That is, the piezoelectric film 10 has a structure in which the piezoelectric layer 20 is sandwiched between electrode layers, and a protective layer is laminated on the surface of the electrode layer that is not in contact with the piezoelectric layer.
- the piezoelectric layer 20 is a polymer composite piezoelectric material containing piezoelectric particles 36 in a matrix 34 containing a polymer material, as conceptually shown in FIG.
- the material for the matrix 34 (matrix and binder) of the polymer composite piezoelectric material constituting the piezoelectric layer 20 it is preferable to use a polymer material that has viscoelasticity at room temperature.
- "normal temperature” refers to a temperature range of about 0 to 50°C.
- the polymer composite piezoelectric material preferably satisfies the following requirements.
- Flexibility For example, when holding a newspaper or magazine in a loosely bent state like a document for portable use, it is constantly subjected to relatively slow and large bending deformation of several Hz or less from the outside. become. At this time, if the polymer composite piezoelectric material is hard, a correspondingly large bending stress will be generated, and cracks will occur at the interface between the polymer matrix and the piezoelectric particles, which may eventually lead to destruction. Therefore, a polymer composite piezoelectric material is required to have appropriate softness. Moreover, if strain energy can be diffused to the outside as heat, stress can be alleviated. Therefore, the loss tangent of the polymer composite piezoelectric material is required to be appropriately large.
- a flexible polymer composite piezoelectric material used as an exciter is required to behave hard against vibrations of 20 Hz to 20 kHz, and to behave softly against vibrations of several Hz or less. Further, the loss tangent of the polymer composite piezoelectric material is required to be appropriately large for vibrations of all frequencies below 20 kHz. Furthermore, it is preferable that the spring constant can be easily adjusted by laminating layers according to the rigidity (hardness, stiffness, spring constant) of the mating material (diaphragm) to which the adhesive layer 104 is attached. The thinner it is, the more energy efficient it can be.
- polymer solids have a viscoelastic relaxation mechanism, and as the temperature increases or the frequency decreases, large-scale molecular motion causes a decrease (relaxation) in the storage modulus (Young's modulus) or a maximum in the loss modulus (absorption). It is observed as Among these, the relaxation caused by micro-Brownian motion of molecular chains in the amorphous region is called principal dispersion, and a very large relaxation phenomenon is observed. The temperature at which this main dispersion occurs is the glass transition point (Tg), and the viscoelastic relaxation mechanism appears most prominently.
- Tg glass transition point
- the polymer composite piezoelectric material (piezoelectric layer 20), by using a polymer material whose glass transition point is at room temperature, in other words, a polymer material that has viscoelasticity at room temperature, for the matrix, it can withstand vibrations of 20Hz to 20kHz. This results in a polymer composite piezoelectric material that is hard and behaves softly when subjected to slow vibrations of several Hz or less. In particular, in order to suitably exhibit this behavior, it is preferable to use a polymer material whose glass transition point at a frequency of 1 Hz is at room temperature, that is, 0 to 50° C., for the matrix of the polymer composite piezoelectric material.
- Various known polymer materials can be used as the polymer material having viscoelasticity at room temperature.
- a polymer material having a maximum value of loss tangent Tan ⁇ of 0.5 or more at a frequency of 1 Hz in a dynamic viscoelasticity test at room temperature, ie, 0 to 50° C. is used.
- the polymer composite piezoelectric material is slowly bent by an external force, stress concentration at the interface between the polymer matrix and the piezoelectric particles at the maximum bending moment portion is alleviated, and high flexibility can be expected.
- the polymer material having viscoelasticity at room temperature preferably has a storage modulus (E') at a frequency of 1 Hz measured by dynamic viscoelasticity measurement of 100 MPa or more at 0°C and 10 MPa or less at 50°C.
- E' storage modulus
- the polymer material having viscoelasticity at room temperature has a dielectric constant of 10 or more at 25°C.
- a voltage is applied to the polymer composite piezoelectric material, a higher electric field is applied to the piezoelectric particles in the matrix, so a large amount of deformation can be expected.
- the polymer material in consideration of securing good moisture resistance, etc., it is also suitable for the polymer material to have a dielectric constant of 10 or less at 25°C.
- polymeric materials that have viscoelasticity at room temperature that meet these conditions include cyanoethylated polyvinyl alcohol (cyanoethylated PVA), polyvinyl acetate, polyvinylidene chloride core acrylonitrile, polystyrene-vinyl polyisoprene block copolymer, and polyvinyl methyl.
- cyanoethylated polyvinyl alcohol cyanoethylated PVA
- polyvinyl acetate polyvinylidene chloride core acrylonitrile
- polystyrene-vinyl polyisoprene block copolymer examples include ketones and polybutyl methacrylate.
- commercially available products such as Hybler 5127 (manufactured by Kuraray Co., Ltd.) can also be suitably used as these polymeric materials.
- the polymer material it is preferable to use a material having a cyanoethyl group, and it is particularly preferable to use
- the polymeric material having viscoelasticity at room temperature it is preferable to use a polymeric material having a cyanoethyl group, and it is particularly preferable to use cyanoethylated PVA. That is, in the present invention, it is preferable for the piezoelectric layer 20 to use a polymeric material having a cyanoethyl group as the matrix 34, and it is particularly preferable to use cyanoethylated PVA.
- the above-mentioned polymeric materials represented by cyanoethylated PVA are also collectively referred to as "polymeric materials having viscoelasticity at room temperature.”
- polymeric materials having viscoelasticity at room temperature may be used alone or in combination (mixture) of multiple types.
- the matrix 34 using such a polymeric material having viscoelasticity at room temperature may be made of a plurality of polymeric materials in combination, if necessary. That is, in addition to the viscoelastic material such as cyanoethylated PVA, other dielectric polymeric materials may be added to the matrix 34 as necessary for the purpose of adjusting dielectric properties and mechanical properties.
- dielectric polymer materials examples include polyvinylidene fluoride, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-trifluoroethylene copolymer, and polyvinylidene fluoride-trifluoroethylene copolymer.
- fluorine-based polymers such as polyvinylidene fluoride-tetrafluoroethylene copolymer, vinylidene cyanide-vinyl acetate copolymer, cyanoethylcellulose, cyanoethylhydroxysucrose, cyanoethylhydroxycellulose, cyanoethylhydroxypullulan, cyanoethyl methacrylate, cyanoethyl acrylate, cyanoethyl Cyano groups such as hydroxyethyl cellulose, cyanoethyl amylose, cyanoethyl hydroxypropyl cellulose, cyanoethyl dihydroxypropyl cellulose, cyanoethyl hydroxypropyl amylose, cyanoethyl polyacrylamide, cyanoethyl polyacrylate, cyanoethyl pullulan, cyanoethyl polyhydroxymethylene, cyanoethyl glycido
- the matrix 34 also includes thermoplastic resins such as vinyl chloride resin, polyethylene, polystyrene, methacrylic resin, polybutene, and isobutylene, for the purpose of adjusting the glass transition point Tg, and Thermosetting resins such as phenol resins, urea resins, melamine resins, alkyd resins, and mica may also be added. Furthermore, for the purpose of improving tackiness, tackifiers such as rosin ester, rosin, terpene, terpene phenol, and petroleum resin may be added.
- thermoplastic resins such as vinyl chloride resin, polyethylene, polystyrene, methacrylic resin, polybutene, and isobutylene
- Thermosetting resins such as phenol resins, urea resins, melamine resins, alkyd resins, and mica may also be added.
- tackifiers such as rosin ester, rosin, terpene, terpene
- the proportion in the matrix 34 is 30% by mass or less. It is preferable that This allows the properties of the added polymer material to be expressed without impairing the viscoelastic relaxation mechanism in the matrix 34, resulting in higher dielectric constant, improved heat resistance, improved adhesion between the piezoelectric particles 36 and the electrode layer, etc. Favorable results can be obtained in this respect.
- the piezoelectric layer 20 is a layer made of a polymer composite piezoelectric material that includes such a matrix 34 and piezoelectric particles 36 .
- Piezoelectric particles 36 are dispersed in matrix 34 .
- the piezoelectric particles 36 are uniformly (substantially uniformly) dispersed in the matrix 34.
- the piezoelectric particles 36 are made of ceramic particles having a perovskite or wurtzite crystal structure.
- Ceramic particles constituting the piezoelectric particles 36 include lead zirconate titanate (PZT), lead lanthanate zirconate titanate (PLZT), barium titanate (BaTiO 3 ), zinc oxide (ZnO), and A solid solution (BFBT) of barium titanate and bismuth ferrite (BiFe 3 ) is exemplified.
- the particle size of the piezoelectric particles 36 there is no limit to the particle size of the piezoelectric particles 36, and it may be selected as appropriate depending on the size of the piezoelectric film 10, the use of the piezoelectric element 50, and the like.
- the particle size of the piezoelectric particles 36 is preferably 1 to 10 ⁇ m. By setting the particle size of the piezoelectric particles 36 within this range, favorable results can be obtained in that the piezoelectric film 10 can have both high piezoelectric properties and flexibility.
- the piezoelectric particles 36 in the piezoelectric layer 20 may be uniformly and regularly dispersed in the matrix 34, or if they are uniformly dispersed, they may be irregularly dispersed in the matrix 34. may have been done.
- the ratio of the matrix 34 to the piezoelectric particles 36 in the piezoelectric layer 20 is not limited, and depends on the size and thickness of the piezoelectric film 10 in the plane direction, the use of the piezoelectric element 50, and It may be set as appropriate depending on the characteristics etc. required of the piezoelectric element 50.
- the volume fraction of the piezoelectric particles 36 in the piezoelectric layer 20 is preferably 30 to 80%, more preferably 50% or more, and therefore even more preferably 50 to 80%.
- the thickness of the piezoelectric layer 20 is not particularly limited, and may be determined as appropriate depending on the use of the piezoelectric element 50, the number of laminated piezoelectric films in the piezoelectric element 50, the characteristics required of the piezoelectric film 10, etc. , just set it.
- the thickness of the piezoelectric layer 20 is preferably 10 to 300 ⁇ m, more preferably 20 to 200 ⁇ m, and even more preferably 30 to 150 ⁇ m.
- the piezoelectric layer 20 is preferably polarized (poled) in the thickness direction.
- the piezoelectric film 10 has a second electrode layer 26 on one side of the piezoelectric layer 20, a second protective layer 30 thereon, and a second electrode layer 26 on one side of the piezoelectric layer 20. It has a structure in which it has a first electrode layer 24 on its surface and a first protective layer 28 thereon.
- the first electrode layer 24 and the second electrode layer 26 form an electrode pair.
- both surfaces of the piezoelectric layer 20 are sandwiched between an electrode pair, that is, a second electrode layer 26 and a first electrode layer 24, and this laminate is sandwiched between a second protective layer 30 and a first protective layer 28. It has a structure in which it is sandwiched between. In this way, in the piezoelectric film 10, the region sandwiched between the second electrode layer 26 and the first electrode layer 24 expands and contracts depending on the applied voltage.
- the second electrode layer 26 and the second protective layer 30, as well as the first electrode layer 24 and the first protective layer 28 are added for convenience in order to explain the piezoelectric film 10. Therefore, the first and second aspects of the present invention have no technical meaning and are unrelated to actual usage conditions.
- the piezoelectric film 10 includes, in addition to these layers, an adhesive layer for pasting the electrode layer and the piezoelectric layer 20, and a pasting layer for pasting the electrode layer and the protective layer. It may have an attached layer.
- the adhesive may be an adhesive or a pressure-sensitive adhesive.
- a polymeric material obtained by removing the piezoelectric particles 36 from the piezoelectric layer 20, that is, the same material as the matrix 34 can also be suitably used.
- the adhesive layer may be provided on both the first electrode layer 24 side and the second electrode layer 26 side, or may be provided only on one of the first electrode layer 24 side and the second electrode layer 26 side. good.
- the first protective layer 28 and the second protective layer 30 cover the first electrode layer 24 and the second electrode layer 26, and also serve to impart appropriate rigidity and mechanical strength to the piezoelectric layer 20.
- the piezoelectric layer 20 consisting of the matrix 34 and the piezoelectric particles 36 exhibits excellent flexibility against slow bending deformation, but depending on the application, it may have low rigidity. or mechanical strength may be insufficient.
- the piezoelectric film 10 is provided with a first protective layer 28 and a second protective layer 30 to compensate for this.
- the first protective layer 28 and the second protective layer 30 have the same structure, except for the arrangement position. Therefore, in the following description, when there is no need to distinguish between the first protective layer 28 and the second protective layer 30, both members are collectively referred to as protective layers.
- the protective layer is not limited and various sheet-like materials can be used, and various resin films are suitably exemplified as an example.
- various resin films are suitably exemplified as an example.
- PET polyethylene terephthalate
- PP polypropylene
- PS polystyrene
- PC polycarbonate
- PPS polyphenylene sulfite
- PMMA polymethyl methacrylate
- PEI polyetherimide
- PI polyimide
- PEN polyethylene naphthalate
- TAC triacetyl cellulose
- cyclic olefin resin and the like are suitably used.
- the thickness of the protective layer there is also no limit to the thickness of the protective layer.
- the thicknesses of the first protective layer 28 and the second protective layer 30 are basically the same, but may be different.
- the rigidity of the protective layer is too high, it not only restricts the expansion and contraction of the piezoelectric layer 20 but also impairs its flexibility. Therefore, the thinner the protective layer is, the more advantageous it is, except when mechanical strength and good handling properties as a sheet-like product are required.
- the thickness of the protective layer is at most twice the thickness of the piezoelectric layer 20, favorable results can be obtained in terms of ensuring both rigidity and appropriate flexibility.
- the thickness of the protective layer is preferably 100 ⁇ m or less, more preferably 50 ⁇ m or less, and even more preferably 25 ⁇ m or less.
- a second electrode layer 26 is provided between the piezoelectric layer 20 and the second protective layer 30, and a first electrode layer 24 is provided between the piezoelectric layer 20 and the first protective layer 28. It is formed.
- the first electrode layer 24 and the second electrode layer 26 are provided to apply a voltage to the piezoelectric layer 20 (piezoelectric film 10).
- the first electrode layer 24 and the second electrode layer 26 are basically the same except for their positions. Therefore, in the following description, when there is no need to distinguish between the first electrode layer 24 and the second electrode layer 26, both members are collectively referred to as electrode layers.
- the material for forming the electrode layer there are no restrictions on the material for forming the electrode layer, and various conductors can be used. Specifically, metals such as carbon, palladium, iron, tin, aluminum, nickel, platinum, gold, silver, copper, titanium, chromium, and molybdenum, alloys thereof, laminates and composites of these metals and alloys, Further, indium tin oxide and the like are exemplified. Alternatively, conductive polymers such as PEDOT/PPS (polyethylenedioxythiophene-polystyrene sulfonic acid) are also exemplified. Among them, copper, aluminum, gold, silver, platinum, and indium tin oxide are preferably exemplified as the electrode layer. Among these, copper is more preferable from the viewpoints of conductivity, cost, flexibility, and the like.
- PEDOT/PPS polyethylenedioxythiophene-polystyrene sulfonic acid
- vapor deposition methods vacuum film formation methods
- film formation by plating film formation by plating
- pasting foil made of the above materials Various known methods are available.
- thin films made of copper, aluminum, or the like formed by vacuum deposition are particularly preferably used as the electrode layer because the flexibility of the piezoelectric film 10 can be ensured.
- a copper thin film formed by vacuum evaporation is particularly preferably used.
- the thickness of the electrode layer there is no limit to the thickness of the electrode layer. Further, the thicknesses of the first electrode layer 24 and the second electrode layer 26 are basically the same, but may be different.
- the rigidity of the electrode layer is too high, it not only restricts the expansion and contraction of the piezoelectric layer 20 but also impairs its flexibility. Therefore, it is advantageous for the electrode layer to be thinner, as long as the electrical resistance does not become too high.
- the product of the thickness of the electrode layer and the Young's modulus be less than the product of the thickness of the protective layer and the Young's modulus, since flexibility will not be significantly impaired.
- the thickness of the electrode layer is The thickness is preferably 1.2 ⁇ m or less, more preferably 0.3 ⁇ m or less, and particularly preferably 0.1 ⁇ m or less.
- the piezoelectric film 10 has a piezoelectric layer 20 formed by dispersing piezoelectric particles 36 in a matrix 34 containing a polymeric material, sandwiched between the first electrode layer 24 and the second electrode layer 26, and further includes:
- This laminate has a structure in which a first protective layer 28 and a second protective layer 30 are sandwiched between them.
- the maximum value of the loss tangent (Tan ⁇ ) at a frequency of 1 Hz as measured by dynamic viscoelasticity exists at room temperature, and it is preferable that the maximum value of 0.1 or more exists at room temperature. More preferred.
- the piezoelectric film 10 is subjected to a relatively slow and large bending deformation of several Hz or less from the outside, the strain energy can be effectively diffused to the outside as heat, so that the polymer matrix and piezoelectric particles are This can prevent cracks from forming at the interface.
- the piezoelectric film 10 preferably has a storage modulus (E') at a frequency of 1 Hz measured by dynamic viscoelasticity measurement of 10 to 30 GPa at 0°C and 1 to 10 GPa at 50°C. Note that this condition also applies to the piezoelectric layer 20. This allows the piezoelectric film 10 to have a large frequency dispersion in storage modulus (E') at room temperature. That is, it is hard against vibrations of 20 Hz to 20 kHz, and can behave soft against vibrations of several Hz or less.
- E' storage modulus
- the piezoelectric film 10 has a product of thickness and storage modulus (E') at a frequency of 1 Hz measured by dynamic viscoelasticity measurement of 1.0 ⁇ 10 5 to 2.0 ⁇ 10 6 N/m at 0°C. , 1.0 ⁇ 10 5 to 1.0 ⁇ 10 6 N/m at 50°C. Note that this condition also applies to the piezoelectric layer 20. Thereby, the piezoelectric film 10 can have appropriate rigidity and mechanical strength without impairing its flexibility and acoustic properties.
- E' thickness and storage modulus
- the piezoelectric film 10 preferably has a loss tangent (Tan ⁇ ) of 0.05 or more at 25° C. and a frequency of 1 kHz in a master curve obtained from dynamic viscoelasticity measurement. Regarding this condition, the piezoelectric layer 20 is also the same. As a result, the frequency characteristics of the speaker using the piezoelectric film 10 are smoothed, and the amount of change in sound quality when the lowest resonance frequency f 0 changes due to a change in the curvature of the speaker can also be reduced.
- Tan ⁇ loss tangent
- the storage modulus (Young's modulus) and loss tangent of the piezoelectric film 10, piezoelectric layer 20, etc. may be measured by a known method.
- the measurement may be performed using a dynamic viscoelasticity measuring device DMS6100 manufactured by SII Nanotechnology.
- the measurement frequency is 0.1Hz to 20Hz (0.1Hz, 0.2Hz, 0.5Hz, 1Hz, 2Hz, 5Hz, 10Hz and 20Hz)
- the measurement temperature is -50 to 150°C. Examples include a temperature increase rate of 2° C./min (in a nitrogen atmosphere), a sample size of 40 mm ⁇ 10 mm (including the clamp area), and a distance between chucks of 20 mm.
- a power source (external power source) is connected to the first electrode layer 24 and the second electrode layer 26 of the piezoelectric film 10, which applies a driving voltage to expand and contract the piezoelectric film 10, that is, supplies driving power.
- the power source is not limited and may be either a direct current power source or an alternating current power source.
- the drive voltage may be appropriately set to a drive voltage that can appropriately drive the piezoelectric film 10, depending on the thickness and forming material of the piezoelectric layer 20 of the piezoelectric film 10.
- electrodes are drawn out from the first electrode layer 24 and the second electrode layer 26 at the protrusion 11b.
- the method of drawing out the electrodes from the first electrode layer 24 and the second electrode layer 26 can be used.
- a method of connecting a conductive material such as copper foil to the first electrode layer 24 and the second electrode layer 26 and drawing out the electrodes to the outside, and a method of penetrating the first protective layer 28 and the second protective layer 30 with a laser or the like are available. Examples include a method of forming a hole, filling the through hole with a conductive material, and drawing out an electrode to the outside.
- suitable electrode extraction methods include the method described in JP-A No. 2014-209724 and the method described in JP-A No. 2016-015354.
- the method for manufacturing a piezoelectric film of the present invention includes: A method for producing a piezoelectric film having a piezoelectric layer made of a polymer composite piezoelectric material containing piezoelectric particles in a matrix containing a polymeric material, and electrode layers provided on both sides of the piezoelectric layer, the method comprising: a piezoelectric layer forming step of forming an unpolarized piezoelectric layer on the main surface of one electrode layer; After the piezoelectric layer forming step, a polarization treatment step of polarizing a part of the piezoelectric layer; After the polarization treatment step, an electrode lamination step of laminating the other electrode layer on the main surface of the piezoelectric layer, In the polarization process, an electrode member is placed facing the main surface of the piezoelectric layer on the opposite side from one electrode layer, and after one electrode layer is connected to the ground, a DC voltage is applied between the electrode member and the electrode member.
- the polarization process is performed by applying This is a method of manufacturing a piezoelectric film in which a polarized region and an unpolarized region are formed in a piezoelectric layer by regulating the region to be polarized.
- the polarization treatment is a corona poling treatment
- the electrode member is a wire-shaped corona electrode.
- a sheet-like material 12a shown in FIG. 9 in which the first electrode layer 24 is formed on the surface of the first protective layer 28 is prepared. Furthermore, a sheet-like material 12c, conceptually shown in FIG. 13, in which a second electrode layer 26 is formed on the surface of a second protective layer 30 is prepared.
- the sheet-like material 12a may be produced by forming a copper thin film or the like as the first electrode layer 24 on the surface of the first protective layer 28 by vacuum evaporation, sputtering, plating, or the like.
- the sheet-like material 12c may be produced by forming a copper thin film or the like as the second electrode layer 26 on the surface of the second protective layer 30 by vacuum evaporation, sputtering, plating, or the like.
- a commercially available sheet material in which a copper thin film or the like is formed on a protective layer may be used as the sheet material 12a and/or the sheet material 12c.
- the sheet-like material 12a and the sheet-like material 12c may be the same or different.
- a protective layer with a separator temporary support
- PET or the like having a thickness of 25 to 100 ⁇ m can be used as the separator.
- the separator may be removed after thermocompression bonding of the electrode layer and the protective layer.
- a paint (coating composition) that will become the piezoelectric layer 20 is applied onto the first electrode layer 24 of the sheet-like material 12a, and then cured to form the piezoelectric layer 20 ( piezoelectric layer formation process).
- a piezoelectric laminate 12b in which the sheet-like material 12a and the piezoelectric layer 20 are laminated is manufactured.
- the piezoelectric layer 20 formed in the piezoelectric layer forming step is in an unpolarized state.
- a piezoelectric layer 20 can be formed depending on the material used to form the piezoelectric layer 20.
- a polymer material such as the above-mentioned cyanoethylated PVA is dissolved in an organic solvent, and then piezoelectric particles 36 such as PZT particles are added and stirred to prepare a paint.
- organic solvent there are no restrictions on the organic solvent, and various organic solvents such as dimethylformamide (DMF), methyl ethyl ketone (MEK), and cyclohexanone can be used.
- DMF dimethylformamide
- MEK methyl ethyl ketone
- cyclohexanone can be used.
- the paint is cast (coated) on the sheet-like material 12a, and the organic solvent is evaporated and dried.
- a piezoelectric laminate 12b having the first electrode layer 24 on the first protective layer 28 and the piezoelectric layer 20 laminated on the first electrode layer 24 was manufactured. do.
- a piezoelectric laminate 12b as shown in FIG. 10 may be produced by extruding it in a sheet form onto the shaped object 12a and cooling it.
- the matrix 34 may contain a polymeric piezoelectric material such as PVDF in addition to the polymeric material having viscoelasticity at room temperature.
- a polymeric piezoelectric material such as PVDF
- the polymer piezoelectric materials to be added to the paint may be dissolved.
- the polymeric piezoelectric material to be added may be added to a polymeric material that is heated and melted and has viscoelasticity at room temperature, and then heated and melted.
- calendaring may be performed if necessary. Calendar processing may be performed once or multiple times.
- calendering is a process in which a surface to be treated is heated and pressed using a heated press, a heated roller, etc. to flatten the surface.
- polarization treatment is performed on the piezoelectric layer 20 of the piezoelectric laminate 12b (polarization treatment step).
- the polarization treatment of the piezoelectric layer 20 may be performed before the calender treatment, it is preferably performed after the calender treatment.
- any known method can be used. Examples include electric field poling, corona poling, and the like, in which a DC electric field is directly applied to the object to be polarized.
- the polarization treatment is performed not in the plane direction of the piezoelectric layer 20 but in the thickness direction.
- the polarization treatment step includes arranging a corona electrode facing the main surface of the piezoelectric layer 20 on the opposite side to one electrode layer (first electrode layer 24), After connecting one electrode layer (first electrode layer) to ground, polarization treatment is performed by applying a voltage between one electrode layer (first electrode layer) and the corona electrode to generate corona discharge.
- This is a corona poling process, and by regulating the area to be polarized, a polarized area and an unpolarized area are formed in the piezoelectric layer 20.
- the length of the region where corona discharge occurs of a wire-shaped corona electrode is made shorter than the width of the piezoelectric layer, thereby regulating the region to be polarized.
- Polarization is performed by arranging an insulator or a conductor connected to ground on a part of the main surface of the piezoelectric layer opposite to one electrode layer (first electrode layer). Examples include methods of regulating areas.
- FIG. 11 is a diagram for explaining a method of regulating the region to be polarized by making the length of the region of the corona electrode where corona discharge occurs shorter than the width of the piezoelectric layer.
- a wire-shaped corona electrode 60 faces the surface (top surface) of the piezoelectric layer 20 of the piezoelectric laminate 12b opposite to the first electrode layer 24 and is movable along this surface. Place.
- the distance between the piezoelectric layer 20 and the corona electrode 60 is, for example, about 1 mm.
- This corona electrode 60 and the first electrode layer 24 are connected to a DC power source, and a DC voltage of several kV, for example, 6 kV is applied between the first electrode layer 24 and the corona electrode 60 from the DC power source to discharge the corona. cause Further, the corona electrode 60 is moved (scanned) along the upper surface of the piezoelectric layer 20 while maintaining the interval to polarize the piezoelectric layer 20. Thereby, the piezoelectric layer 20 is polarized in the thickness direction.
- a part of the wire-shaped corona electrode 60 is covered with a first covering member 62 made of an insulator such as alumina, so that the wire-shaped corona electrode 60 faces the area covered with the first covering member 62.
- Corona discharge is not generated in the region of the piezoelectric layer 20, and polarization treatment is prevented. That is, in the example shown in FIG. 11, by covering a part of the wire-shaped corona electrode 60 with the first covering member 62, the length of the region of the corona electrode 60 where corona discharge occurs is made smaller than the width of the piezoelectric layer 20. It's also shorter. Thereby, unpolarized regions 20b and polarized regions 20a can be formed in the piezoelectric layer 20.
- the position, length, etc. of the first covering member 62 may be appropriately set according to the region of the piezoelectric layer 20 in which the unpolarized region 20b is formed. Further, as the material of the first covering member 62, alumina, zirconia, etc. can be used.
- the corona electrode 60 is covered with the first covering member 62 to form the unpolarized region 20b in the piezoelectric layer 20, but the present invention is not limited to this.
- the length of the corona electrode 60 itself may be made shorter than the width of the piezoelectric layer 20 (width in the longitudinal direction of the wire-shaped corona electrode), and the corona electrode may be placed in a region of the piezoelectric layer 20 that does not face the corona electrode 60.
- the unpolarized region 20b may be formed without causing discharge.
- a portion of the corona electrode 60 may be made of tungsten wire to make corona discharge less likely to occur and form the unpolarized region 20b.
- FIG. 12 shows a method of regulating the area to be polarized by placing an insulator or a conductor connected to ground on a part of the main surface of the piezoelectric layer opposite to one electrode layer. It is a figure for explaining.
- a wire-shaped corona electrode 60 faces the surface (top surface) of the piezoelectric layer 20 of the piezoelectric laminate 12b opposite to the first electrode layer 24 and is movable along this surface. Place.
- the distance between the piezoelectric layer 20 and the corona electrode 60 is, for example, about 1 mm.
- This corona electrode 60 and the first electrode layer 24 are connected to a DC power source, and a DC voltage of several kV, for example, 6 kV is applied between the first electrode layer 24 and the corona electrode 60 from the DC power source to discharge the corona. cause Further, the corona electrode 60 is moved (scanned) along the upper surface of the piezoelectric layer 20 while maintaining the interval to polarize the piezoelectric layer 20. Thereby, the piezoelectric layer 20 is polarized in the thickness direction.
- a part of the upper surface of the piezoelectric layer 20 is covered with an insulating or conductive second covering member 64 connected to the ground. Corona discharge is not generated in the region, or the region exposed to corona discharge is regulated to prevent it from being polarized. Thereby, unpolarized regions 20b and polarized regions 20a can be formed in the piezoelectric layer 20.
- the position, length, etc. of the second covering member 64 may be appropriately set according to the area in the piezoelectric layer 20 where the unpolarized area 20b is formed.
- the insulating second covering member 64 alumina, a rubber sheet, etc. can be used. Further, as the conductive second covering member 64, a copper foil sheet or the like can be used. Note that when using the conductive second covering member 64, the second covering member 64 is connected to ground.
- this laminate is thermocompressed using a hot press device, a heating roller, etc., with the first protective layer 28 and the second protective layer 30 sandwiched therebetween, thereby forming the piezoelectric laminate 12b and the sheet-like material 12c. are bonded together to produce a piezoelectric film 10 as shown in FIG.
- the piezoelectric film 10 may be produced by bonding the piezoelectric laminate 12b and the sheet-like material 12c together using an adhesive, and preferably further press-bonding them.
- this piezoelectric film 10 may be manufactured using a cut sheet-like sheet material 12a, a sheet-like material 12c, etc., or may be manufactured using a roll-to-roll method. Good too.
- the produced piezoelectric film may be cut into desired shapes according to various uses.
- the polarized region of the piezoelectric film 10 produced in this way is polarized not in the plane direction but in the thickness direction, and great piezoelectric properties can be obtained even without stretching treatment after polarization treatment. Therefore, the polarized region of the piezoelectric film 10 has no in-plane anisotropy in its piezoelectric properties, and when a driving voltage is applied, it expands and contracts isotropically in all directions in the plane.
- the piezoelectric layer 20 includes piezoelectric particles 36 in the matrix 34. Further, a second electrode layer 26 and a first electrode layer 24 are provided so as to sandwich the piezoelectric layer 20 in the thickness direction.
- a voltage is applied to the second electrode layer 26 and the first electrode layer 24 of the piezoelectric film 10 having such a piezoelectric layer 20, in the polarization region 20a, the piezoelectric particles 36 move in the polarization direction according to the applied voltage. Expand and contract.
- the piezoelectric film 10 (polarized region 20a of the piezoelectric layer 20) contracts in the thickness direction.
- the piezoelectric film 10 also expands and contracts in the in-plane direction due to the Poisson ratio. This expansion/contraction is approximately 0.01 to 0.1%.
- the thickness of the piezoelectric layer 20 is preferably about 10 to 300 ⁇ m. Therefore, the expansion and contraction in the thickness direction is very small, about 0.3 ⁇ m at most.
- the piezoelectric film 10, that is, the piezoelectric layer 20 (polarized region 20a) has a size much larger than its thickness in the plane direction. Therefore, for example, if the length of the piezoelectric film 10 is 20 cm, the piezoelectric film 10 expands and contracts by a maximum of about 0.2 mm by applying a voltage.
- the diaphragm 102 is attached to the piezoelectric film 10 with an adhesive layer. Therefore, the diaphragm 102 is bent by the expansion and contraction of the piezoelectric film 10, and as a result, the diaphragm 102 vibrates in the thickness direction. Due to this vibration in the thickness direction, the diaphragm 102 generates sound. That is, the diaphragm 102 vibrates according to the magnitude of the voltage (driving voltage) applied to the piezoelectric film 10 and generates sound according to the driving voltage applied to the piezoelectric film 10.
- the sound pressure level can be improved. If the mass of the piezoelectric film 10 is large, the diaphragm 102 will bend, which may suppress the vibration of the diaphragm 102 during driving. On the other hand, when the mass of the piezoelectric film 10 is small, the resonance frequency becomes high, and vibration of the diaphragm 102 at low frequencies may be suppressed. Considering these points, it is preferable that the mass of the piezoelectric film 10 is appropriately adjusted according to the spring constant of the diaphragm 102.
- Example 1 ⁇ Preparation of piezoelectric film> A piezoelectric film was produced by the method shown in FIGS. 9 to 13 described above. First, cyanoethylated PVA (CR-V, manufactured by Shin-Etsu Chemical Co., Ltd.) was dissolved in dimethylformamide (DMF) at the composition ratio shown below. Thereafter, PZT particles as piezoelectric particles were added to this solution in the composition ratio shown below, and the mixture was stirred with a propeller mixer (rotation speed: 2000 rpm) to prepare a paint for forming a piezoelectric layer.
- cyanoethylated PVA CR-V, manufactured by Shin-Etsu Chemical Co., Ltd.
- DMF dimethylformamide
- ⁇ PZT particles ⁇ 300 parts by mass ⁇ Cyanoethylated PVA ⁇ 30 parts by mass ⁇ DMF ⁇ 70 parts by mass
- the PZT particles used were obtained by sintering commercially available PZT raw material powder at 1000 to 1200° C., and then crushing and classifying it to an average particle size of 5 ⁇ m.
- a sheet-like product was prepared by vacuum-depositing a 0.3 ⁇ m thick copper thin film onto a 4 ⁇ m thick PET film. That is, in this example, the first electrode layer and the second electrode layer are copper vapor deposited thin films with a thickness of 0.3 ⁇ m, and the first protective layer and the second protective layer are PET films with a thickness of 4 ⁇ m.
- the previously prepared paint for forming the piezoelectric layer was applied onto the first electrode layer (copper deposited thin film) of the sheet using a slide coater. The coating material was applied so that the thickness of the coating film after drying was 50 ⁇ m. Next, the sheet material coated with the paint was heated and dried on a hot plate at 120° C. to evaporate the DMF.
- a piezoelectric laminate having a first electrode layer made of copper on a first protective layer made of PET, and a piezoelectric layer (polymer composite piezoelectric layer) with a thickness of 50 ⁇ m on top of the first electrode layer was produced. did.
- the produced piezoelectric laminate was cut into a size of 170 mm x 200 mm.
- the produced piezoelectric layer was polarized in the thickness direction by corona poling using a wire-shaped corona electrode. At that time, a 20 mm wide region along one of the 200 mm long edges of the top surface of the piezoelectric layer was covered with an insulating second covering member (material: nitrile rubber) to perform polarization treatment. As a result, a piezoelectric layer having polarized regions and unpolarized regions was formed. Note that a rubber magnet may be used as the second covering member.
- a sheet-like material in which the same thin film was deposited on a PET film was laminated with the second electrode layer (copper thin film side) facing the piezoelectric layer.
- the laminate of the piezoelectric laminate and the sheet-like material is thermocompression bonded at a temperature of 120°C using a laminator device, so that the piezoelectric layer and the second electrode layer are adhered and bonded to form a piezoelectric layer.
- a film was produced.
- the produced piezoelectric film was folded twice in the direction of the 170 mm side, and the piezoelectric films were laminated with an adhesive layer (acrylic adhesive) to form a laminated part with a length of 200 mm and a width of 50 mm, and a laminated part with a length of 200 mm and a width of 20 mm.
- a piezoelectric element having a protrusion was fabricated. When folded back, the unpolarized region became a protrusion.
- Example 1 A piezoelectric film was produced to produce a piezoelectric element in the same manner as in Example 1, except that when performing the corona poling treatment, the entire surface of the piezoelectric layer was polarized without covering it with the second covering member.
- a music signal was input to the piezoelectric element via an amplifier using a commercially available CD sound source, and a sensory evaluation was performed at a location 1 meter in front of the diaphragm to evaluate the sound quality on a 10-point scale.
- Table 1 shows the average scores of a total of 20 testers. The results are shown in Table 1.
- Example 2 The size was 50 mm x 200 mm, and when performing corona poling treatment, a 3 mm wide insulating second covering member (material: nitrile rubber) was placed along each of the four edges of the top surface of the piezoelectric layer. A piezoelectric film was produced in the same manner as in Example 1 except that the polarization treatment was performed.
- Example 2 A piezoelectric film was produced in the same manner as in Example 2, except that when performing the corona poling treatment, the upper surface of the piezoelectric layer was not covered with the second covering member and the entire surface was subjected to the polarization treatment.
- a pink noise signal was input to the piezoelectric film via an amplifier using a noise signal generator, and the piezoelectric film was driven continuously for 10,000 hours to examine changes in sound pressure and appearance abnormalities before and after the test.
- the results are shown in Table 2.
- the piezoelectric film and piezoelectric element of the present invention can be used, for example, in the manufacture of various sensors such as sonic sensors, ultrasonic sensors, pressure sensors, tactile sensors, strain sensors, and vibration sensors (particularly for infrastructure inspections such as crack detection and foreign object detection).
- sensors such as sonic sensors, ultrasonic sensors, pressure sensors, tactile sensors, strain sensors, and vibration sensors (particularly for infrastructure inspections such as crack detection and foreign object detection).
- acoustic devices such as microphones, pickups, speakers, and exciters
- Specific applications include noise cancellers (used in cars, trains, airplanes, robots, etc.), artificial vocal cords, and pest/vermin intrusion.
- Examples include protective buzzers, furniture, wallpaper, photographs, helmets, goggles, headrests, signage, robots, etc.), haptics, ultrasonic probes, and hydrophones used in automobiles, smartphones, smart watches, games, etc.
- ultrasonic transducers such as, actuators used for water droplet prevention, transportation, stirring, dispersion, polishing, etc., vibration dampers used for containers, vehicles, buildings, sports equipment such as skis and rackets, and roads, floors, etc. It can be suitably used as a vibration power generation device for use in mattresses, chairs, shoes, tires, wheels, computer keyboards, and the like.
Abstract
The present invention provides: a piezoelectric film that, in a piezoelectric element having a protrusion for connecting to an external power source, can suppress noise generated by vibrations in the protrusion and also suppresses peeling when the piezoelectric film is used by being attached to a diaphragm; and a related piezoelectric element, electroacoustic transducer, and method for manufacturing a piezoelectric film. The piezoelectric film has a piezoelectric layer comprising a polymer composite piezoelectric material containing piezoelectric particles in a matrix containing a polymer material, and an electrode layer provided on both sides of the piezoelectric layer, the piezoelectric layer having unpolarized regions that are not polarized in some portions.
Description
本発明は、圧電フィルム、圧電素子および電気音響変換器、ならびに、圧電フィルムの製造方法に関する。
The present invention relates to a piezoelectric film, a piezoelectric element, an electroacoustic transducer, and a method for manufacturing a piezoelectric film.
圧電素子は、各種の物品に接触して取り付けることで、物品を振動させて音を出す、いわゆるエキサイター（励起子）として、各種の用途に利用されている。例えば、画像表示パネル、スクリーン等にエキサイターを取り付けて、これらを振動させることで、スピーカーの代わりに音を出すことができる。
Piezoelectric elements are used for a variety of purposes as so-called exciters, which vibrate and produce sound by attaching them in contact with various objects. For example, by attaching an exciter to an image display panel, screen, etc., and causing these to vibrate, it is possible to produce sound instead of a speaker.
圧電素子として、圧電体層を電極層および保護層で挟持した圧電フィルムを用いることが提案されている。また、圧電フィルムを複数層積層して圧電素子として用いることも提案されている。
It has been proposed to use a piezoelectric film in which a piezoelectric layer is sandwiched between an electrode layer and a protective layer as a piezoelectric element. It has also been proposed to laminate multiple layers of piezoelectric films and use them as piezoelectric elements.
例えば、特許文献１には、高分子材料を含むマトリックス中に圧電体粒子を分散してなる高分子複合圧電体と、高分子複合圧電体の両面に形成された電極層とを有し、動的粘弾性測定による周波数１ｋＨｚでの損失正接が、５０℃超１５０℃以下の温度範囲に０．１以上となる極大値が存在し、かつ、５０℃での値が０．０８以上である圧電フィルムが記載されている。また、特許文献１には、圧電フィルムを１回以上折り返して、圧電フィルムを複数層、積層した圧電素子が記載されている。
For example, Patent Document 1 discloses a polymer composite piezoelectric material having piezoelectric particles dispersed in a matrix containing a polymer material, and an electrode layer formed on both surfaces of the polymer composite piezoelectric material. A piezoelectric product whose loss tangent at a frequency of 1 kHz, determined by physical viscoelasticity measurement, has a maximum value of 0.1 or more in a temperature range exceeding 50°C and 150°C or less, and whose value at 50°C is 0.08 or more. Film is listed. Further, Patent Document 1 describes a piezoelectric element in which a piezoelectric film is folded back one or more times and multiple layers of piezoelectric films are laminated.
圧電フィルムを折り返してなる圧電素子は、振動板に貼付けて、振動板を振動させることで、振動板から音を発生させるエキサイターとして用いられる。このような圧電素子の電極層に外部電源を接続するために、圧電フィルムが積層された積層部から面方向に突出する突出部を設けて、この突出部にて電極層に外部電源を接続することが考えられている。圧電素子を駆動させるために突出部に設けられた電極層と外部電源との接続部から電圧を印加すると、突出部で顕著に発熱し、最悪の場合、熱暴走を起こし連続駆動できなくなるおそれがある。このような発熱抑制のためには、突出部の面積は広い方が好ましい。
A piezoelectric element made by folding a piezoelectric film is used as an exciter that generates sound from the diaphragm by attaching it to a diaphragm and causing the diaphragm to vibrate. In order to connect an external power source to the electrode layer of such a piezoelectric element, a protrusion that protrudes in the plane direction from the laminated portion of the piezoelectric film is provided, and the external power source is connected to the electrode layer at this protrusion. That is what is being considered. When voltage is applied from the connection between the electrode layer provided on the protruding part and an external power supply to drive the piezoelectric element, the protruding part generates significant heat, and in the worst case, there is a risk of thermal runaway and the inability to continuously drive the piezoelectric element. be. In order to suppress such heat generation, it is preferable that the area of the protrusion is wide.
しかしながら、本発明者らの検討によれば、圧電素子が突出部を有すると、この突出部にも振動が生じて、不要な音（ノイズ）が発生するという問題が生じることがわかった。
However, according to studies conducted by the present inventors, it has been found that when the piezoelectric element has a protrusion, vibrations also occur in the protrusion, resulting in the generation of unnecessary sound (noise).
また、圧電フィルムあるいは圧電素子を振動板に貼り付けて電気音響変換器とした場合には、圧電フィルムあるいは圧電素子の振動によって、振動板と、圧電フィルムあるいは圧電素子とが剥離するという問題があることがわかった。
Furthermore, when a piezoelectric film or piezoelectric element is attached to a diaphragm to form an electroacoustic transducer, there is a problem in that the diaphragm and the piezoelectric film or piezoelectric element separate from each other due to the vibration of the piezoelectric film or piezoelectric element. I understand.
本発明の課題は、このような従来技術の問題点を解決することにあり、外部電源と接続するための突出部を有する圧電素子において、突出部に振動が生じてノイズが発生することを抑制でき、また、振動板に貼り付けて用いる際の剥離を抑制できる、圧電フィルム、圧電素子および電気音響変換器、ならびに、圧電フィルムの製造方法を提供することにある。
An object of the present invention is to solve the problems of the prior art, and to suppress the generation of noise caused by vibration in the protrusion in a piezoelectric element having a protrusion for connection to an external power source. It is an object of the present invention to provide a piezoelectric film, a piezoelectric element, an electroacoustic transducer, and a method for manufacturing a piezoelectric film, which can be used by attaching the piezoelectric film to a diaphragm and which can suppress peeling when used.
上述した課題を解決するために、本発明は、以下の構成を有する。
［１］ 高分子材料を含むマトリックス中に圧電体粒子を含む高分子複合圧電体からなる圧電体層と、圧電体層の両面に設けられる電極層と、を有する圧電フィルムにおいて、
圧電体層が一部に分極されていない未分極領域を有する、圧電フィルム。
［２］ 電極対を構成する一対の電極層に挟持された領域において、圧電体層が、厚さ方向に分極された分極領域と、未分極領域とを有する、［１］に記載の圧電フィルム。
［３］ 未分極領域が、圧電フィルムの外縁部に存在する、［１］に記載の圧電フィルム。
［４］ ［１］～［３］のいずれかに記載の圧電フィルムを１回以上、折り返すことにより、圧電フィルムを、複数層、積層してなる圧電素子であって、
平面視において、圧電フィルムが２層以上重なる積層部と、積層部から突出する突出部を有し、
突出部は、電極層と外部電源とを接続するための接続部を有し、
未分極領域が突出部に存在する、圧電素子。
［５］ ［１］～［３］のいずれかに記載の圧電フィルムを、振動板に貼り付けてなる、電気音響変換器。
［６］ ［４］に記載の圧電素子を、振動板に貼り付けてなる、電気音響変換器。
［７］ 圧電フィルムの電極層と、振動板とが電気的に接続されていない、［５］に記載の電気音響変換器。
［８］ 圧電フィルムの電極層と、振動板とが電気的に接続されていない、［６］に記載の電気音響変換器。
［９］ 高分子材料を含むマトリックス中に圧電体粒子を含む高分子複合圧電体からなる圧電体層と、圧電体層の両面に設けられる電極層と、を有する圧電フィルムの製造方法であって、
一方の電極層の主面に、未分極の圧電体層を形成する圧電体層形成工程と、
圧電体層形成工程の後に、圧電体層の一部を分極処理する分極処理工程と、
分極処理工程の後に、圧電体層の主面に他方の電極層を積層する電極積層工程と、を有し、
分極処理工程は、圧電体層の一方の電極層とは反対側の主面に対面して電極部材を配置して、一方の電極層をアースに接続した後、電極部材との間に直流電圧を印加して分極処理を行うものであり、
分極処理される領域を規制することにより、圧電体層に分極された分極領域と、分極されていない未分極領域とを形成する、圧電フィルムの製造方法。
［１０］ 分極処理がコロナポーリング処理であり、
電極部材がワイヤー状のコロナ電極である、［９］に記載の圧電フィルムの製造方法。
［１１］ 分極処理工程において、ワイヤー状のコロナ電極の、コロナ放電が生じる領域の長さを圧電体層の幅よりも短くすることで、分極処理される領域を規制する、［１０］に記載の圧電フィルムの製造方法。
［１２］ 分極処理工程において、圧電体層の一方の電極層とは反対側の主面上の一部に絶縁体またはアースに接続された導電体を配置することで、分極処理される領域を規制する、［９］に記載の圧電フィルムの製造方法。 In order to solve the above-mentioned problems, the present invention has the following configuration.
[1] A piezoelectric film having a piezoelectric layer made of a polymer composite piezoelectric material containing piezoelectric particles in a matrix containing a polymer material, and electrode layers provided on both sides of the piezoelectric layer,
A piezoelectric film in which a piezoelectric layer partially has an unpolarized region.
[2] The piezoelectric film according to [1], wherein the piezoelectric layer has a polarized region polarized in the thickness direction and an unpolarized region in the region sandwiched between the pair of electrode layers constituting the electrode pair. .
[3] The piezoelectric film according to [1], wherein the unpolarized region is present at the outer edge of the piezoelectric film.
[4] A piezoelectric element formed by laminating multiple layers of piezoelectric films by folding back the piezoelectric film according to any one of [1] to [3] one or more times,
In plan view, the piezoelectric film has a laminated part where two or more layers overlap and a protrusion part that protrudes from the laminated part,
The protruding portion has a connecting portion for connecting the electrode layer and an external power source,
A piezoelectric element in which unpolarized regions are present in the protrusions.
[5] An electroacoustic transducer comprising the piezoelectric film according to any one of [1] to [3] attached to a diaphragm.
[6] An electroacoustic transducer comprising the piezoelectric element according to [4] attached to a diaphragm.
[7] The electroacoustic transducer according to [5], wherein the electrode layer of the piezoelectric film and the diaphragm are not electrically connected.
[8] The electroacoustic transducer according to [6], wherein the electrode layer of the piezoelectric film and the diaphragm are not electrically connected.
[9] A method for producing a piezoelectric film, comprising: a piezoelectric layer made of a polymer composite piezoelectric material containing piezoelectric particles in a matrix containing a polymer material; and electrode layers provided on both sides of the piezoelectric layer. ,
a piezoelectric layer forming step of forming an unpolarized piezoelectric layer on the main surface of one electrode layer;
After the piezoelectric layer forming step, a polarization treatment step of polarizing a part of the piezoelectric layer;
After the polarization treatment step, an electrode lamination step of laminating the other electrode layer on the main surface of the piezoelectric layer,
In the polarization process, an electrode member is placed facing the main surface of the piezoelectric layer on the opposite side from one electrode layer, and after one electrode layer is connected to the ground, a DC voltage is applied between the electrode member and the electrode member. The polarization process is performed by applying
A method for manufacturing a piezoelectric film, in which a polarized region and an unpolarized region are formed in a piezoelectric layer by regulating the region to be polarized.
[10] The polarization treatment is a corona poling treatment,
The method for producing a piezoelectric film according to [9], wherein the electrode member is a wire-shaped corona electrode.
[11] In the polarization treatment step, the region to be polarized is regulated by making the length of the region of the wire-shaped corona electrode where corona discharge occurs shorter than the width of the piezoelectric layer, as described in [10]. A method for manufacturing a piezoelectric film.
[12] In the polarization process, an insulator or a conductor connected to the ground is placed on a part of the main surface of the piezoelectric layer opposite to one of the electrode layers to control the area to be polarized. The method for producing a piezoelectric film according to [9].
［１］ 高分子材料を含むマトリックス中に圧電体粒子を含む高分子複合圧電体からなる圧電体層と、圧電体層の両面に設けられる電極層と、を有する圧電フィルムにおいて、
圧電体層が一部に分極されていない未分極領域を有する、圧電フィルム。
［２］ 電極対を構成する一対の電極層に挟持された領域において、圧電体層が、厚さ方向に分極された分極領域と、未分極領域とを有する、［１］に記載の圧電フィルム。
［３］ 未分極領域が、圧電フィルムの外縁部に存在する、［１］に記載の圧電フィルム。
［４］ ［１］～［３］のいずれかに記載の圧電フィルムを１回以上、折り返すことにより、圧電フィルムを、複数層、積層してなる圧電素子であって、
平面視において、圧電フィルムが２層以上重なる積層部と、積層部から突出する突出部を有し、
突出部は、電極層と外部電源とを接続するための接続部を有し、
未分極領域が突出部に存在する、圧電素子。
［５］ ［１］～［３］のいずれかに記載の圧電フィルムを、振動板に貼り付けてなる、電気音響変換器。
［６］ ［４］に記載の圧電素子を、振動板に貼り付けてなる、電気音響変換器。
［７］ 圧電フィルムの電極層と、振動板とが電気的に接続されていない、［５］に記載の電気音響変換器。
［８］ 圧電フィルムの電極層と、振動板とが電気的に接続されていない、［６］に記載の電気音響変換器。
［９］ 高分子材料を含むマトリックス中に圧電体粒子を含む高分子複合圧電体からなる圧電体層と、圧電体層の両面に設けられる電極層と、を有する圧電フィルムの製造方法であって、
一方の電極層の主面に、未分極の圧電体層を形成する圧電体層形成工程と、
圧電体層形成工程の後に、圧電体層の一部を分極処理する分極処理工程と、
分極処理工程の後に、圧電体層の主面に他方の電極層を積層する電極積層工程と、を有し、
分極処理工程は、圧電体層の一方の電極層とは反対側の主面に対面して電極部材を配置して、一方の電極層をアースに接続した後、電極部材との間に直流電圧を印加して分極処理を行うものであり、
分極処理される領域を規制することにより、圧電体層に分極された分極領域と、分極されていない未分極領域とを形成する、圧電フィルムの製造方法。
［１０］ 分極処理がコロナポーリング処理であり、
電極部材がワイヤー状のコロナ電極である、［９］に記載の圧電フィルムの製造方法。
［１１］ 分極処理工程において、ワイヤー状のコロナ電極の、コロナ放電が生じる領域の長さを圧電体層の幅よりも短くすることで、分極処理される領域を規制する、［１０］に記載の圧電フィルムの製造方法。
［１２］ 分極処理工程において、圧電体層の一方の電極層とは反対側の主面上の一部に絶縁体またはアースに接続された導電体を配置することで、分極処理される領域を規制する、［９］に記載の圧電フィルムの製造方法。 In order to solve the above-mentioned problems, the present invention has the following configuration.
[1] A piezoelectric film having a piezoelectric layer made of a polymer composite piezoelectric material containing piezoelectric particles in a matrix containing a polymer material, and electrode layers provided on both sides of the piezoelectric layer,
A piezoelectric film in which a piezoelectric layer partially has an unpolarized region.
[2] The piezoelectric film according to [1], wherein the piezoelectric layer has a polarized region polarized in the thickness direction and an unpolarized region in the region sandwiched between the pair of electrode layers constituting the electrode pair. .
[3] The piezoelectric film according to [1], wherein the unpolarized region is present at the outer edge of the piezoelectric film.
[4] A piezoelectric element formed by laminating multiple layers of piezoelectric films by folding back the piezoelectric film according to any one of [1] to [3] one or more times,
In plan view, the piezoelectric film has a laminated part where two or more layers overlap and a protrusion part that protrudes from the laminated part,
The protruding portion has a connecting portion for connecting the electrode layer and an external power source,
A piezoelectric element in which unpolarized regions are present in the protrusions.
[5] An electroacoustic transducer comprising the piezoelectric film according to any one of [1] to [3] attached to a diaphragm.
[6] An electroacoustic transducer comprising the piezoelectric element according to [4] attached to a diaphragm.
[7] The electroacoustic transducer according to [5], wherein the electrode layer of the piezoelectric film and the diaphragm are not electrically connected.
[8] The electroacoustic transducer according to [6], wherein the electrode layer of the piezoelectric film and the diaphragm are not electrically connected.
[9] A method for producing a piezoelectric film, comprising: a piezoelectric layer made of a polymer composite piezoelectric material containing piezoelectric particles in a matrix containing a polymer material; and electrode layers provided on both sides of the piezoelectric layer. ,
a piezoelectric layer forming step of forming an unpolarized piezoelectric layer on the main surface of one electrode layer;
After the piezoelectric layer forming step, a polarization treatment step of polarizing a part of the piezoelectric layer;
After the polarization treatment step, an electrode lamination step of laminating the other electrode layer on the main surface of the piezoelectric layer,
In the polarization process, an electrode member is placed facing the main surface of the piezoelectric layer on the opposite side from one electrode layer, and after one electrode layer is connected to the ground, a DC voltage is applied between the electrode member and the electrode member. The polarization process is performed by applying
A method for manufacturing a piezoelectric film, in which a polarized region and an unpolarized region are formed in a piezoelectric layer by regulating the region to be polarized.
[10] The polarization treatment is a corona poling treatment,
The method for producing a piezoelectric film according to [9], wherein the electrode member is a wire-shaped corona electrode.
[11] In the polarization treatment step, the region to be polarized is regulated by making the length of the region of the wire-shaped corona electrode where corona discharge occurs shorter than the width of the piezoelectric layer, as described in [10]. A method for manufacturing a piezoelectric film.
[12] In the polarization process, an insulator or a conductor connected to the ground is placed on a part of the main surface of the piezoelectric layer opposite to one of the electrode layers to control the area to be polarized. The method for producing a piezoelectric film according to [9].
本発明によれば、外部電源と接続するための突出部を有する圧電素子において、突出部に振動が生じてノイズが発生することを抑制でき、また、振動板に貼り付けて用いる際の剥離を抑制できる、圧電フィルム、圧電素子および電気音響変換器、ならびに、圧電フィルムの製造方法を提供することができる。
According to the present invention, in a piezoelectric element having a protruding part for connecting to an external power source, it is possible to suppress noise generation due to vibration in the protruding part, and also to prevent peeling when used by pasting it on a diaphragm. A piezoelectric film, a piezoelectric element, an electroacoustic transducer, and a method for manufacturing a piezoelectric film can be provided.
以下、本発明の圧電フィルム、圧電素子および電気音響変換器、ならびに、圧電フィルムの製造方法について、添付の図面に示される好適実施例を基に、詳細に説明する。
Hereinafter, the piezoelectric film, piezoelectric element, electroacoustic transducer, and method for manufacturing the piezoelectric film of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.
以下に記載する構成要件の説明は、本発明の代表的な実施態様に基づいてなされることがあるが、本発明はそのような実施態様に限定されるものではない。
なお、本明細書において、「～」を用いて表される数値範囲は、「～」の前後に記載される数値を下限値および上限値として含む範囲を意味する。 Although the description of the constituent elements described below may be made based on typical embodiments of the present invention, the present invention is not limited to such embodiments.
Note that in this specification, a numerical range expressed using "~" means a range that includes the numerical values written before and after "~" as the lower limit and upper limit.
なお、本明細書において、「～」を用いて表される数値範囲は、「～」の前後に記載される数値を下限値および上限値として含む範囲を意味する。 Although the description of the constituent elements described below may be made based on typical embodiments of the present invention, the present invention is not limited to such embodiments.
Note that in this specification, a numerical range expressed using "~" means a range that includes the numerical values written before and after "~" as the lower limit and upper limit.
［圧電フィルムおよび圧電素子］
本発明の圧電フィルムは、
高分子材料を含むマトリックス中に圧電体粒子を含む高分子複合圧電体からなる圧電体層と、圧電体層の両面に設けられる電極層と、を有する圧電フィルムにおいて、
圧電体層が一部に分極されていない未分極領域を有する、圧電フィルムである。 [Piezoelectric film and piezoelectric element]
The piezoelectric film of the present invention is
A piezoelectric film having a piezoelectric layer made of a polymer composite piezoelectric material containing piezoelectric particles in a matrix containing a polymer material, and electrode layers provided on both sides of the piezoelectric layer,
The piezoelectric film is a piezoelectric film in which the piezoelectric layer partially has an unpolarized region.
本発明の圧電フィルムは、
高分子材料を含むマトリックス中に圧電体粒子を含む高分子複合圧電体からなる圧電体層と、圧電体層の両面に設けられる電極層と、を有する圧電フィルムにおいて、
圧電体層が一部に分極されていない未分極領域を有する、圧電フィルムである。 [Piezoelectric film and piezoelectric element]
The piezoelectric film of the present invention is
A piezoelectric film having a piezoelectric layer made of a polymer composite piezoelectric material containing piezoelectric particles in a matrix containing a polymer material, and electrode layers provided on both sides of the piezoelectric layer,
The piezoelectric film is a piezoelectric film in which the piezoelectric layer partially has an unpolarized region.
また、本発明の圧電素子は、上記圧電フィルムを１回以上、折り返すことにより、圧電フィルムを、複数層、積層してなる圧電素子であって、
平面視において、圧電フィルムが２層以上重なる積層部と、積層部から突出する突出部を有し、
突出部は、電極層と外部電源とを接続するための接続部を有し、
未分極領域が突出部に存在する、圧電素子である。 Further, the piezoelectric element of the present invention is a piezoelectric element formed by laminating a plurality of layers of piezoelectric films by folding the piezoelectric film one or more times,
In plan view, the piezoelectric film has a laminated part where two or more layers overlap and a protrusion part that protrudes from the laminated part,
The protruding portion has a connecting portion for connecting the electrode layer and an external power source,
It is a piezoelectric element in which unpolarized regions are present in the protrusions.
平面視において、圧電フィルムが２層以上重なる積層部と、積層部から突出する突出部を有し、
突出部は、電極層と外部電源とを接続するための接続部を有し、
未分極領域が突出部に存在する、圧電素子である。 Further, the piezoelectric element of the present invention is a piezoelectric element formed by laminating a plurality of layers of piezoelectric films by folding the piezoelectric film one or more times,
In plan view, the piezoelectric film has a laminated part where two or more layers overlap and a protrusion part that protrudes from the laminated part,
The protruding portion has a connecting portion for connecting the electrode layer and an external power source,
It is a piezoelectric element in which unpolarized regions are present in the protrusions.
図１に、本発明の圧電フィルムを有する本発明の圧電素子の一例を模式的に表す斜視図を示す。図２に、図１の圧電素子の側面図を示す。図３に、図１の圧電素子が有する圧電フィルムを折り返す前の状態を表す斜視図を示す。なお、平面図とは、圧電フィルム１０を複数層積層した積層方向から見た図である。
FIG. 1 is a perspective view schematically showing an example of a piezoelectric element of the present invention having a piezoelectric film of the present invention. FIG. 2 shows a side view of the piezoelectric element of FIG. 1. FIG. 3 shows a perspective view of the piezoelectric film of the piezoelectric element of FIG. 1 before it is folded back. Note that the plan view is a view seen from the lamination direction in which a plurality of piezoelectric films 10 are laminated.
図１および図２に示す圧電素子５０は、矩形状の１枚の圧電フィルム１０ａを、一方向に２回、折り返すことにより、３層の圧電フィルム１０ａを積層したものである。すなわち、この圧電素子５０は、３層の圧電フィルム１０ａを積層した積層圧電素子である。
図１では、図面を簡略化して、圧電素子５０の構成を明瞭に示すために省略するが、圧電フィルム１０ａは、圧電体層２０の両面に電極層を有し、両電極層を覆って、保護層を有するものである。また、図３では、保護層の図示を省略している。
また、以下の説明では、圧電フィルム１０ａを折り返す方向（図１中左右方向）を折り返し方向という。 Thepiezoelectric element 50 shown in FIGS. 1 and 2 is made by laminating three layers of piezoelectric films 10a by folding back one rectangular piezoelectric film 10a twice in one direction. That is, this piezoelectric element 50 is a laminated piezoelectric element in which three layers of piezoelectric films 10a are laminated.
Although omitted in FIG. 1 to simplify the drawing and clearly show the structure of thepiezoelectric element 50, the piezoelectric film 10a has electrode layers on both sides of the piezoelectric layer 20, and covers both electrode layers. It has a protective layer. Further, in FIG. 3, illustration of the protective layer is omitted.
Furthermore, in the following description, the direction in which thepiezoelectric film 10a is folded back (the left-right direction in FIG. 1) is referred to as the folding direction.
図１では、図面を簡略化して、圧電素子５０の構成を明瞭に示すために省略するが、圧電フィルム１０ａは、圧電体層２０の両面に電極層を有し、両電極層を覆って、保護層を有するものである。また、図３では、保護層の図示を省略している。
また、以下の説明では、圧電フィルム１０ａを折り返す方向（図１中左右方向）を折り返し方向という。 The
Although omitted in FIG. 1 to simplify the drawing and clearly show the structure of the
Furthermore, in the following description, the direction in which the
後述する図８に示すように、圧電フィルム１０ａは、高分子材料を含むマトリックス３４中に圧電体粒子３６を含む高分子複合圧電体からなる圧電体層２０と、圧電体層２０の両面に設けられる電極層（第１電極層２４および第２電極層２６）と、を有する。また、圧電フィルム１０ａは、各電極層の上に設けられる保護層（第１保護層２８および第２保護層３０）を有している。
As shown in FIG. 8, which will be described later, the piezoelectric film 10a includes a piezoelectric layer 20 made of a polymer composite piezoelectric material containing piezoelectric particles 36 in a matrix 34 containing a polymer material, and a piezoelectric layer 20 provided on both sides of the piezoelectric layer 20. (the first electrode layer 24 and the second electrode layer 26). Moreover, the piezoelectric film 10a has a protective layer (first protective layer 28 and second protective layer 30) provided on each electrode layer.
圧電体層２０は、厚さ方向に分極されている。圧電体層２０を挟持する電極層（電極対）に電圧を印加すると、印加した電圧に応じて圧電体層２０中の圧電体粒子３６が分極方向に伸縮する。その結果、圧電フィルム１０ａ（圧電体層２０）が厚さ方向に収縮する。同時に、ポアゾン比の関係で、圧電フィルム１０ａは、面方向にも伸縮する。これにより、圧電フィルム１０ａは、圧電性能を発現することができる。
圧電フィルムの各構成要素については後に詳述する。 Thepiezoelectric layer 20 is polarized in the thickness direction. When a voltage is applied to the electrode layers (electrode pair) that sandwich the piezoelectric layer 20, the piezoelectric particles 36 in the piezoelectric layer 20 expand and contract in the polarization direction according to the applied voltage. As a result, the piezoelectric film 10a (piezoelectric layer 20) contracts in the thickness direction. At the same time, the piezoelectric film 10a also expands and contracts in the plane direction due to the Poisson ratio. Thereby, the piezoelectric film 10a can exhibit piezoelectric performance.
Each component of the piezoelectric film will be detailed later.
圧電フィルムの各構成要素については後に詳述する。 The
Each component of the piezoelectric film will be detailed later.
このような圧電性能を有する圧電フィルム１０ａを折り返すことにより、圧電フィルムを、複数層、積層してなる圧電素子５０とすることができる。
図１および図２に示す例では、圧電素子５０は、平面視において３層の圧電フィルム１０ａが重なる積層部１１ａと、積層部１１ａから面方向の外側に突出する突出部１１ｂとを有する。すなわち、圧電素子５０は、１枚の圧電フィルム１０ａを２回折り返す際に、図１中、下面側の層から２層は、折り返し方向の長さが略同じ長さになるようにし、最上面側の層となる圧電フィルム１０ａの長さを他の層の圧電フィルム１０ａよりも長くして、折り返し方向の一端が他の層の圧電フィルム１０ａと重ならないようにすることで、突出部１１ｂを設けたものである。 By folding back thepiezoelectric film 10a having such piezoelectric performance, the piezoelectric element 50 can be formed by laminating a plurality of layers of piezoelectric films.
In the example shown in FIGS. 1 and 2, thepiezoelectric element 50 has a laminated part 11a in which three layers of piezoelectric films 10a overlap in plan view, and a protrusion part 11b that protrudes outward in the plane direction from the laminated part 11a. That is, in the piezoelectric element 50, when one piezoelectric film 10a is folded twice, the two layers from the bottom side in FIG. 1 have approximately the same length in the folding direction, and the top surface By making the length of the piezoelectric film 10a serving as the side layer longer than the piezoelectric film 10a of the other layer so that one end in the folding direction does not overlap with the piezoelectric film 10a of the other layer, the protruding portion 11b is It was established.
図１および図２に示す例では、圧電素子５０は、平面視において３層の圧電フィルム１０ａが重なる積層部１１ａと、積層部１１ａから面方向の外側に突出する突出部１１ｂとを有する。すなわち、圧電素子５０は、１枚の圧電フィルム１０ａを２回折り返す際に、図１中、下面側の層から２層は、折り返し方向の長さが略同じ長さになるようにし、最上面側の層となる圧電フィルム１０ａの長さを他の層の圧電フィルム１０ａよりも長くして、折り返し方向の一端が他の層の圧電フィルム１０ａと重ならないようにすることで、突出部１１ｂを設けたものである。 By folding back the
In the example shown in FIGS. 1 and 2, the
なお、図１に示す例では、圧電素子５０は、圧電フィルム１０ａを２回折り返し、３層の圧電フィルム１０ａが積層されたものとしたがこれに限定はされず、圧電素子は、２層の圧電フィルムが積層されたものであってもよいし、４層以上の圧電フィルムが積層されたものであってもよい。
In the example shown in FIG. 1, the piezoelectric element 50 is made by folding back the piezoelectric film 10a twice and laminating three layers of piezoelectric films 10a, but the piezoelectric element is not limited to this. It may be one in which piezoelectric films are laminated, or one in which four or more layers of piezoelectric films are laminated.
積層部１１ａで隣接する圧電フィルム１０ａの層同士は、粘着層１４によって貼着されている。
圧電フィルム同士を貼着する粘着層１４は、隣接する圧電フィルム１０を貼着可能であれば、公知のものが、各種、利用可能である。粘着層１４としては、後述する振動板と圧電素子とを貼着する貼着層と同様の材料を用いることができる。 Adjacent layers of thepiezoelectric film 10a in the laminated portion 11a are adhered to each other by an adhesive layer 14.
As theadhesive layer 14 for adhering piezoelectric films to each other, various known adhesive layers can be used as long as they can adhere adjacent piezoelectric films 10 to each other. As the adhesive layer 14, the same material as the adhesive layer for pasting the diaphragm and the piezoelectric element, which will be described later, can be used.
圧電フィルム同士を貼着する粘着層１４は、隣接する圧電フィルム１０を貼着可能であれば、公知のものが、各種、利用可能である。粘着層１４としては、後述する振動板と圧電素子とを貼着する貼着層と同様の材料を用いることができる。 Adjacent layers of the
As the
本発明において、積層部１１ａとは、平面視において、すなわち、図１において圧電素子を上方（あるいは下方）から見た際に、圧電フィルムが２層以上重なる領域である。すなわち、図１および図２に示すように、圧電フィルム１０ａの層が３層重なる領域が、積層部１１ａである。
In the present invention, the laminated portion 11a is a region where two or more layers of piezoelectric films overlap when viewed in plan, that is, when the piezoelectric element is viewed from above (or from below) in FIG. That is, as shown in FIGS. 1 and 2, a region where three layers of the piezoelectric film 10a overlap is the laminated portion 11a.
一方、突出部１１ｂとは、積層部１１ａから面方向に突出する領域であり、平面視において、他の層と重なっていない領域である。図１および図２に示す例では、図中、最上層の右側端部が突出部１１ｂである。
On the other hand, the protruding portion 11b is a region that protrudes from the laminated portion 11a in the surface direction, and is a region that does not overlap with other layers in plan view. In the example shown in FIGS. 1 and 2, the right end of the uppermost layer in the figures is the protrusion 11b.
図１に示すように、突出部１１ｂには、第１電極層２４および第２電極層２６（以下、まとめて、電極層ともいう）と、外部電極とを接続するための導線４０および導線４２が形成されている。図２に示すように、圧電フィルム１０ａが保護層（第１保護層２８および第２保護層３０）を有する場合には、突出部１１ｂの領域の保護層（第１保護層２８および第２保護層３０）に貫通孔を形成して、電極層を露出させて、接続部を設けて導線４０および導線４２それぞれと電気的に接続される。貫通孔の形成方法には、制限はなく、保護層の形成材料に応じて、レーザー加工、溶剤を用いた溶解除去、および、機械研磨等の機械的な加工等の公知の方法で行えばよい。
As shown in FIG. 1, the protrusion 11b includes a conductive wire 40 and a conductive wire 42 for connecting the first electrode layer 24 and the second electrode layer 26 (hereinafter also collectively referred to as electrode layers) and an external electrode. is formed. As shown in FIG. 2, when the piezoelectric film 10a has a protective layer (the first protective layer 28 and the second protective layer 30), the protective layer (the first protective layer 28 and the second protective layer 30) in the region of the protrusion 11b is A through hole is formed in the layer 30) to expose the electrode layer, and a connecting portion is provided to be electrically connected to the conductive wire 40 and the conductive wire 42, respectively. There are no restrictions on the method for forming the through holes, and depending on the material for forming the protective layer, known methods such as laser processing, dissolution and removal using a solvent, and mechanical processing such as mechanical polishing may be used. .
接続部には、銀ペーストなどの導電性金属ペースト、導電性カーボンペースト、および、導電性ナノインク等の公知の導電性材料を充填して外部電源に接続される導線が接続される。
なお、突出部１１ｂにおける電極層と導線との接続方法には、制限はなく、公知の各種の方法が利用可能である。 The connecting portion is connected to a conductive wire filled with a known conductive material such as a conductive metal paste such as a silver paste, a conductive carbon paste, or a conductive nano ink and connected to an external power source.
Note that there is no restriction on the method of connecting the electrode layer and the conductive wire in the protrudingportion 11b, and various known methods can be used.
なお、突出部１１ｂにおける電極層と導線との接続方法には、制限はなく、公知の各種の方法が利用可能である。 The connecting portion is connected to a conductive wire filled with a known conductive material such as a conductive metal paste such as a silver paste, a conductive carbon paste, or a conductive nano ink and connected to an external power source.
Note that there is no restriction on the method of connecting the electrode layer and the conductive wire in the protruding
本発明の圧電素子５０は、突出部１１ｂに設けられた接続部を介して外部電源を用いて電極層に電圧を印加することで、圧電素子５０を駆動させる。圧電素子５０が駆動されると、圧電素子５０が面方向に伸縮し、圧電素子５０が貼着された振動板を撓ませて、結果として振動板を振動させて音を発生させる。振動板は、圧電素子５０に印加した駆動電圧の大きさに応じて振動して、圧電素子５０に印加した駆動電圧に応じた音を発生する。
すなわち、圧電素子５０は、エキサイターとして用いることができる。 Thepiezoelectric element 50 of the present invention is driven by applying a voltage to the electrode layer using an external power source via the connection part provided on the protrusion 11b. When the piezoelectric element 50 is driven, the piezoelectric element 50 expands and contracts in the plane direction, bends the diaphragm to which the piezoelectric element 50 is attached, and as a result vibrates the diaphragm to generate sound. The diaphragm vibrates according to the magnitude of the driving voltage applied to the piezoelectric element 50, and generates sound according to the driving voltage applied to the piezoelectric element 50.
That is, thepiezoelectric element 50 can be used as an exciter.
すなわち、圧電素子５０は、エキサイターとして用いることができる。 The
That is, the
ここで、前述のとおり、従来の圧電素子２５０（図１４参照）において、圧電素子２５０を駆動させるために突出部２１１ｂに設けられた電極層と外部電源との接続部から電圧を印加すると、突出部２１１ｂにも振動が生じて、不要な音（ノイズ）が発生するという問題が生じることがわかった。
Here, as described above, in the conventional piezoelectric element 250 (see FIG. 14), when a voltage is applied from the connection between the electrode layer provided on the protrusion 211b and the external power source in order to drive the piezoelectric element 250, the protrusion It has been found that vibration also occurs in the portion 211b, causing a problem that unnecessary sound (noise) is generated.
これに対して、本発明の圧電素子５０は、突出部１１ｂの圧電体層２０が未分極領域２０ｂを有する。図１および図２に示す例では、圧電素子５０は、突出部１１ｂの圧電体層２０の全域が分極されていない未分極領域２０ｂである。また、突出部１１ｂ以外の領域、すなわち、積層部１１ａの圧電体層２０は、全域が、厚さ方向に分極された分極領域２０ａである。
In contrast, in the piezoelectric element 50 of the present invention, the piezoelectric layer 20 of the protrusion 11b has an unpolarized region 20b. In the example shown in FIGS. 1 and 2, the piezoelectric element 50 has an unpolarized region 20b in which the entire piezoelectric layer 20 of the protrusion 11b is not polarized. Further, the entire area of the piezoelectric layer 20 of the laminated portion 11a other than the protruding portion 11b is a polarized region 20a polarized in the thickness direction.
従って、圧電素子５０が有する圧電フィルム１０ａの折り返し前の状態、言い換えると、折り返した圧電フィルム１０ａを広げた状態では、図３に示すように、圧電フィルム１０ａは、圧電体層２０の一部に分極されていない未分極領域２０ｂを有し、それ以外の領域（積層部１１ａとなる領域）は厚さ方向に分極された分極領域２０ａである。言い換えると、圧電フィルム１０ａは、折り返した際に突出部１１ｂとなる領域の圧電体層２０が未分極領域２０ｂであり、それ以外の領域（積層部１１ａとなる領域）は厚さ方向に分極された分極領域２０ａである。
図４に、説明のため第２電極層２６の図示を省略した圧電フィルム１０ａの斜視図を示す。図４に示すように、圧電フィルム１０ａは、矩形状であり、１つの端辺に沿った所定の幅の領域に未分極領域２０ｂを有している。すなわち、未分極領域２０ｂは、圧電フィルム１０ａの外縁部に存在している。 Therefore, in the state before folding thepiezoelectric film 10a of the piezoelectric element 50, in other words, in the state in which the folded piezoelectric film 10a is unfolded, the piezoelectric film 10a is partially attached to the piezoelectric layer 20, as shown in FIG. It has an unpolarized region 20b that is not polarized, and the other region (the region that becomes the laminated portion 11a) is a polarized region 20a that is polarized in the thickness direction. In other words, in the piezoelectric film 10a, the area of the piezoelectric layer 20 that becomes the protruding part 11b when folded back is the unpolarized area 20b, and the other area (the area that becomes the laminated part 11a) is polarized in the thickness direction. This is the polarized region 20a.
FIG. 4 shows a perspective view of thepiezoelectric film 10a with the second electrode layer 26 omitted for explanation. As shown in FIG. 4, the piezoelectric film 10a has a rectangular shape and has an unpolarized region 20b in a region of a predetermined width along one edge. That is, the unpolarized region 20b exists at the outer edge of the piezoelectric film 10a.
図４に、説明のため第２電極層２６の図示を省略した圧電フィルム１０ａの斜視図を示す。図４に示すように、圧電フィルム１０ａは、矩形状であり、１つの端辺に沿った所定の幅の領域に未分極領域２０ｂを有している。すなわち、未分極領域２０ｂは、圧電フィルム１０ａの外縁部に存在している。 Therefore, in the state before folding the
FIG. 4 shows a perspective view of the
また、図３に示すように、圧電フィルム１０ａは、一対の電極対（第１電極層２４および第２電極層２６）に挟持された領域において、圧電体層２０が、厚さ方向に分極された分極領域２０ａと、未分極領域２０ｂとを有している。すなわち、分極領域２０ａを挟持する電極層と、未分極領域２０ｂを挟持する電極層とは一体である。従って、圧電フィルム１０ａを折り返して圧電素子５０とし、未分極領域２０ｂが突出部１１ｂに存在するようにした場合でも、突出部１１ｂに外部電源と接続する接続部を設けることで、積層部１１ａとなる分極領域２０ａに適正に電圧を印加することができる。
Further, as shown in FIG. 3, in the piezoelectric film 10a, the piezoelectric layer 20 is polarized in the thickness direction in the region sandwiched between the pair of electrodes (the first electrode layer 24 and the second electrode layer 26). It has a polarized region 20a and an unpolarized region 20b. That is, the electrode layer sandwiching the polarized region 20a and the electrode layer sandwiching the unpolarized region 20b are integral. Therefore, even if the piezoelectric film 10a is folded back to form the piezoelectric element 50 and the unpolarized region 20b is present in the protrusion 11b, by providing the protrusion 11b with a connecting part for connecting to an external power source, the laminated part 11a and A voltage can be appropriately applied to the polarized region 20a.
前述のとおり、圧電体層２０（圧電フィルム１０ａ）は、厚さ方向に分極されることにより、印加電圧に応じて伸縮する圧電性能を発現する。そのため、圧電体層２０が分極されている積層部１１ａに、突出部１１ｂの接続部を介して電極層（電極対）に電圧が印加されると、圧電素子５０が圧電性能を発現して、面方向に伸縮する。一方で、圧電体層２０が分極されていない未分極領域２０ｂは、突出部１１ｂの電極層に電圧が印加されても伸縮しない。従って、突出部１１ｂに振動が生じることがなく、不要な音（ノイズ）が発生することを抑止できる。
As described above, the piezoelectric layer 20 (piezoelectric film 10a) is polarized in the thickness direction, thereby exhibiting piezoelectric performance that expands and contracts in accordance with the applied voltage. Therefore, when a voltage is applied to the electrode layer (electrode pair) of the laminated portion 11a in which the piezoelectric layer 20 is polarized through the connection portion of the protruding portion 11b, the piezoelectric element 50 exhibits piezoelectric performance. Stretch and contract in the plane direction. On the other hand, the unpolarized region 20b in which the piezoelectric layer 20 is not polarized does not expand or contract even when a voltage is applied to the electrode layer of the protrusion 11b. Therefore, vibration does not occur in the protruding portion 11b, and generation of unnecessary sound (noise) can be suppressed.
ここで、図１等に示す例では、突出部１１ｂの圧電体層２０の全域が未分極領域２０ｂである構成としたがこれに限定はされず、突出部１１ｂの圧電体層２０の少なくとも一部が未分極領域２０ｂであればよい。突出部１１ｂによる不要な音（ノイズ）が発生することを抑止する観点からは、突出部１１ｂの圧電体層２０の全域が未分極領域２０ｂであることが好ましい。
Here, in the example shown in FIG. 1 etc., the entire area of the piezoelectric layer 20 of the protrusion 11b is configured as the unpolarized region 20b, but the present invention is not limited to this, and at least one portion of the piezoelectric layer 20 of the protrusion 11b is It suffices if the portion is the unpolarized region 20b. From the viewpoint of suppressing unnecessary sound (noise) caused by the protrusion 11b, it is preferable that the entire area of the piezoelectric layer 20 of the protrusion 11b is the unpolarized region 20b.
また、図１等に示す例では、圧電体層２０の突出部１１ｂ以外の領域（積層部１１ａとなる領域）は、全域が分極領域２０ａである構成としたがこれに限定はされず、積層部１１ａとなる領域の一部に未分極領域２０ｂを有していてもよい。圧電素子５０を適正に駆動し、高い圧電性能を得られる観点から、積層部１１ａとなる領域は、全域が分極領域２０ａであることが好ましい。
In addition, in the example shown in FIG. 1, etc., the entire region other than the protruding portion 11b of the piezoelectric layer 20 (the region that becomes the laminated portion 11a) is configured to be the polarized region 20a, but the structure is not limited to this, and the laminated An unpolarized region 20b may be included in a part of the region that becomes part 11a. From the viewpoint of appropriately driving the piezoelectric element 50 and obtaining high piezoelectric performance, it is preferable that the entire region that becomes the laminated portion 11a is the polarized region 20a.
ここで、分極領域と未分極領域とは以下のようにして計測することができる。
Here, the polarized region and the unpolarized region can be measured as follows.
高分子材料を含むマトリックス中に圧電体粒子を分散してなる高分子複合圧電体を圧電体層として用いる圧電フィルムにおいて、圧電体粒子として、ＰＺＴ等の強誘電性材料が用いられる。この強誘電性材料の結晶構造は、自発分極の方向が異なる多くの分域（ドメイン）に分かれており、この状態では各分域の自発分極とそれによって生ずる圧電効果も相互に打ち消し合うため、全体としては圧電性は見られない。
A ferroelectric material such as PZT is used as the piezoelectric particles in a piezoelectric film that uses a polymer composite piezoelectric material formed by dispersing piezoelectric particles in a matrix containing a polymer material as a piezoelectric layer. The crystal structure of this ferroelectric material is divided into many domains with different directions of spontaneous polarization, and in this state, the spontaneous polarization of each domain and the resulting piezoelectric effect cancel each other out. No piezoelectricity is observed as a whole.
そのため、このような圧電フィルムにおいては、圧電体層にポーリング等の電気的な分極処理を施し、外部からある値以上の電界を加えることで、各分域の自発分極の方向を揃えることが行われている。分極処理された圧電体粒子は、外部からの電界に応じて圧電効果を示すようになる。これにより、圧電フィルムは、印加電圧に応答して、圧電フィルム自身が面方向に伸縮し、面に垂直な方向に振動することで、振動（音）と電気信号とを変換する。
Therefore, in such piezoelectric films, it is possible to align the direction of spontaneous polarization in each domain by applying electrical polarization processing such as poling to the piezoelectric layer and applying an external electric field of a certain value or more. It is being said. The polarized piezoelectric particles exhibit a piezoelectric effect in response to an external electric field. Thereby, the piezoelectric film expands and contracts in the plane direction in response to the applied voltage, and vibrates in a direction perpendicular to the plane, thereby converting vibration (sound) and electrical signals.
一般に、このような圧電体層（圧電体粒子）の結晶構造の解析方法として、Ｘ線回折法（ＸＲＤ）が利用されており、ＸＲＤにより結晶内部で原子がどのように配列しているかを調べることができ、これにより、分極領域と未分極領域とを判別できる。
Generally, X-ray diffraction (XRD) is used to analyze the crystal structure of such piezoelectric layers (piezoelectric particles), and XRD is used to examine how atoms are arranged inside the crystal. This makes it possible to distinguish between polarized regions and unpolarized regions.
具体的には、圧電体層２０である高分子複合圧電体をＸ線回折法（ＸＲＤ）で評価した際の、圧電体粒子に由来する（００２）面ピーク強度（ｃドメイン）と、（２００）面ピーク強度（ａドメイン）との比率αが、１以上であれば分極領域とみなし、１未満であれば未分極領域とみなす。このＸＲＤによる評価におけるＸ線の照射エリアは１ｃｍ角四方とし、圧電体層の面内のＸ方向およびＹ方向に１ｍｍの間隔を空けて２次元的に行い、分極領域と未分極領域とを計測することができる。
Specifically, when the polymer composite piezoelectric material that is the piezoelectric layer 20 is evaluated by X-ray diffraction method (XRD), the (002) plane peak intensity (c domain) derived from the piezoelectric particles and the (200 ) If the ratio α to the plane peak intensity (a domain) is 1 or more, it is regarded as a polarized region, and if it is less than 1, it is regarded as an unpolarized region. The X-ray irradiation area in this XRD evaluation was 1 cm square, and the evaluation was performed two-dimensionally with a 1 mm interval in the X and Y directions within the plane of the piezoelectric layer, and the polarized and unpolarized regions were measured. can do.
ここで、（００２）面ピーク強度とは、ＸＲＤ解析（θ―２θ法）により得られるＸＲＤパターンにおいて、４３．５°付近の正方晶のピークであり、（２００）面ピーク強度とは、ＸＲＤ解析により得られるＸＲＤパターンにおいて、４５°付近の正方晶のピークである。（００２）面ピーク強度は、Ｘ線の回折面（圧電フィルムの面内方向）に対して分極軸が垂直なドメイン（ｃドメイン）の割合に対応しており、（２００）面ピーク強度は、Ｘ線の回折面に対して分極軸が平行なドメイン（ａドメイン）の割合に対応している。本来、圧電体の分極処理とはｃドメインを分極反転（１８０°ドメインスイッチング）させる行為であるが、この１８０°ドメインスイッチング自体はＸＲＤ解析では判別できない。ただし、１８０°ドメインスイッチング（１８０°ドメイン壁の消失）に伴い、それまで１８０°ドメイン壁にクランプされていた９０°ドメイン壁が容易に動けるようになり、外部からの機械的および／または電気的刺激に応じて所謂９０°ドメインモーション（aドメイン⇔ｃドメイン）が発生する。つまり、ＸＲＤで分極処理後にｃドメインの比率が高くなっていれば、１８０°ドメイン壁が消失、すなわちｃドメインの分極反転が十分に進んでいるため、高い圧電性を得られる。
ＸＲＤ解析は、Ｘ線回折装置（PANalytical製 X’Pert PRO）等を用いて行うことができる。 Here, the (002) plane peak intensity is the tetragonal peak around 43.5° in the XRD pattern obtained by XRD analysis (θ-2θ method), and the (200) plane peak intensity is the In the XRD pattern obtained by analysis, this is a tetragonal peak around 45°. The (002) plane peak intensity corresponds to the proportion of domains (c domains) whose polarization axis is perpendicular to the X-ray diffraction plane (in-plane direction of the piezoelectric film), and the (200) plane peak intensity is It corresponds to the proportion of domains (a-domains) whose polarization axes are parallel to the X-ray diffraction plane. Originally, polarization processing of a piezoelectric body is an act of inverting the polarization of the c domain (180° domain switching), but this 180° domain switching itself cannot be determined by XRD analysis. However, with 180° domain switching (disappearance of the 180° domain wall), the 90° domain wall, which was previously clamped to the 180° domain wall, can now move easily and A so-called 90° domain motion (a-domain⇔c-domain) occurs in response to the stimulus. In other words, if the ratio of the c-domain is high after polarization treatment by XRD, the 180° domain wall has disappeared, that is, the polarization inversion of the c-domain has progressed sufficiently, and high piezoelectricity can be obtained.
XRD analysis can be performed using an X-ray diffraction device (X'Pert PRO manufactured by PANalytical) or the like.
ＸＲＤ解析は、Ｘ線回折装置（PANalytical製 X’Pert PRO）等を用いて行うことができる。 Here, the (002) plane peak intensity is the tetragonal peak around 43.5° in the XRD pattern obtained by XRD analysis (θ-2θ method), and the (200) plane peak intensity is the In the XRD pattern obtained by analysis, this is a tetragonal peak around 45°. The (002) plane peak intensity corresponds to the proportion of domains (c domains) whose polarization axis is perpendicular to the X-ray diffraction plane (in-plane direction of the piezoelectric film), and the (200) plane peak intensity is It corresponds to the proportion of domains (a-domains) whose polarization axes are parallel to the X-ray diffraction plane. Originally, polarization processing of a piezoelectric body is an act of inverting the polarization of the c domain (180° domain switching), but this 180° domain switching itself cannot be determined by XRD analysis. However, with 180° domain switching (disappearance of the 180° domain wall), the 90° domain wall, which was previously clamped to the 180° domain wall, can now move easily and A so-called 90° domain motion (a-domain⇔c-domain) occurs in response to the stimulus. In other words, if the ratio of the c-domain is high after polarization treatment by XRD, the 180° domain wall has disappeared, that is, the polarization inversion of the c-domain has progressed sufficiently, and high piezoelectricity can be obtained.
XRD analysis can be performed using an X-ray diffraction device (X'Pert PRO manufactured by PANalytical) or the like.
このような圧電素子５０は、振動板に貼り付けられて電気音響変換器として用いられる。
図５に、上述した圧電素子５０を有する電気音響変換器の一例を模式的に示す。
図５に示す電気音響変換器１００ａは、圧電素子５０と、振動板１０２を有する。圧電素子５０は、図１等に示す例と同様の構成を有する。圧電素子５０と振動板１０２とは、図示しない粘着層によって貼着されている。 Such apiezoelectric element 50 is attached to a diaphragm and used as an electroacoustic transducer.
FIG. 5 schematically shows an example of an electroacoustic transducer having thepiezoelectric element 50 described above.
Theelectroacoustic transducer 100a shown in FIG. 5 includes a piezoelectric element 50 and a diaphragm 102. The piezoelectric element 50 has the same configuration as the example shown in FIG. 1 and the like. The piezoelectric element 50 and the diaphragm 102 are attached to each other with an adhesive layer (not shown).
図５に、上述した圧電素子５０を有する電気音響変換器の一例を模式的に示す。
図５に示す電気音響変換器１００ａは、圧電素子５０と、振動板１０２を有する。圧電素子５０は、図１等に示す例と同様の構成を有する。圧電素子５０と振動板１０２とは、図示しない粘着層によって貼着されている。 Such a
FIG. 5 schematically shows an example of an electroacoustic transducer having the
The
このような電気音響変換器１００ａは、圧電素子５０の圧電フィルム１０ａに駆動電圧を印加することで、圧電フィルム１０ａが面方向に伸縮し、この圧電フィルム１０ａの伸縮によって、圧電素子５０が面方向に伸縮する。
この圧電素子５０の面方向の伸縮によって、振動板１０２が撓み、その結果、振動板１０２が、厚さ方向に振動する。この厚さ方向の振動によって、振動板１０２は、音を発生する。振動板１０２は、圧電フィルム１０ａに印加した駆動電圧の大きさに応じて振動して、圧電フィルム１０ａに印加した駆動電圧に応じた音を発生する。 In such anelectroacoustic transducer 100a, by applying a driving voltage to the piezoelectric film 10a of the piezoelectric element 50, the piezoelectric film 10a expands and contracts in the plane direction, and due to the expansion and contraction of the piezoelectric film 10a, the piezoelectric element 50 expands and contracts.
The expansion and contraction of thepiezoelectric element 50 in the plane direction causes the diaphragm 102 to bend, and as a result, the diaphragm 102 vibrates in the thickness direction. Due to this vibration in the thickness direction, the diaphragm 102 generates sound. The diaphragm 102 vibrates according to the magnitude of the driving voltage applied to the piezoelectric film 10a, and generates sound according to the driving voltage applied to the piezoelectric film 10a.
この圧電素子５０の面方向の伸縮によって、振動板１０２が撓み、その結果、振動板１０２が、厚さ方向に振動する。この厚さ方向の振動によって、振動板１０２は、音を発生する。振動板１０２は、圧電フィルム１０ａに印加した駆動電圧の大きさに応じて振動して、圧電フィルム１０ａに印加した駆動電圧に応じた音を発生する。 In such an
The expansion and contraction of the
振動板１０２は、好ましい態様として、可撓性を有するものである。なお、本発明において、可撓性を有するとは、一般的な解釈における可撓性を有すると同義であり、曲げること、および、撓めることが可能であることを示し、具体的には、破壊および損傷を生じることなく、曲げ伸ばしができることを示す。
The diaphragm 102 preferably has flexibility. In addition, in the present invention, having flexibility is synonymous with having flexibility in a general interpretation, and indicates that it is possible to bend and bend. , indicating that it can be bent and stretched without breaking or damage.
振動板１０２は、好ましくは可撓性を有するものであれば、制限はなく、各種のシート状物（板状物、フィルム）が利用可能である。
一例として、ポリエチレンテレフタレート（ＰＥＴ）、ポリプロピレン（ＰＰ）、ポリスチレン（ＰＳ）、ポリカーボネート（ＰＣ）、ポリフェニレンサルファイト（ＰＰＳ）、ポリメチルメタクリレート（ＰＭＭＡ）、ポリエーテルイミド（ＰＥＩ）、ポリイミド（ＰＩ）、ポリエチレンナフタレート（ＰＥＮ）、トリアセチルセルロース（ＴＡＣ）および環状オレフィン系樹脂等からなる樹脂フィルム、発泡ポリスチレン、発泡スチレンおよび発泡ポリエチレン等からなる発泡プラスチック、ならびに、波状にした板紙の片面または両面に他の板紙をはりつけてなる各種の段ボール材等が例示される。 Thediaphragm 102 is not particularly limited as long as it is preferably flexible, and various sheet-like materials (plate-like materials, films) can be used.
Examples include polyethylene terephthalate (PET), polypropylene (PP), polystyrene (PS), polycarbonate (PC), polyphenylene sulfite (PPS), polymethyl methacrylate (PMMA), polyetherimide (PEI), polyimide (PI), Resin films made of polyethylene naphthalate (PEN), triacetyl cellulose (TAC), cyclic olefin resins, etc., foamed polystyrene, foamed plastics made of foamed styrene, foamed polyethylene, etc., and corrugated paperboard on one or both sides. Examples include various corrugated cardboard materials made by gluing paperboard.
一例として、ポリエチレンテレフタレート（ＰＥＴ）、ポリプロピレン（ＰＰ）、ポリスチレン（ＰＳ）、ポリカーボネート（ＰＣ）、ポリフェニレンサルファイト（ＰＰＳ）、ポリメチルメタクリレート（ＰＭＭＡ）、ポリエーテルイミド（ＰＥＩ）、ポリイミド（ＰＩ）、ポリエチレンナフタレート（ＰＥＮ）、トリアセチルセルロース（ＴＡＣ）および環状オレフィン系樹脂等からなる樹脂フィルム、発泡ポリスチレン、発泡スチレンおよび発泡ポリエチレン等からなる発泡プラスチック、ならびに、波状にした板紙の片面または両面に他の板紙をはりつけてなる各種の段ボール材等が例示される。 The
Examples include polyethylene terephthalate (PET), polypropylene (PP), polystyrene (PS), polycarbonate (PC), polyphenylene sulfite (PPS), polymethyl methacrylate (PMMA), polyetherimide (PEI), polyimide (PI), Resin films made of polyethylene naphthalate (PEN), triacetyl cellulose (TAC), cyclic olefin resins, etc., foamed polystyrene, foamed plastics made of foamed styrene, foamed polyethylene, etc., and corrugated paperboard on one or both sides. Examples include various corrugated cardboard materials made by gluing paperboard.
また、電気音響変換器１００ａでは、可撓性を有するものであれば、振動板１０２として、有機エレクトロルミネセンス（ＯＬＥＤ（Organic Light Emitting Diode））ディスプレイ、液晶ディスプレイ、マイクロＬＥＤ（Light Emitting Diode）ディスプレイ、および、無機エレクトロルミネセンスディスプレイなどの表示デバイス等も好適に利用可能である。
In the electroacoustic transducer 100a, the diaphragm 102 may be an organic electroluminescence (OLED) display, a liquid crystal display, or a microLED (Light Emitting Diode) display, as long as it has flexibility. , and display devices such as inorganic electroluminescent displays can also be suitably used.
なお、電気音響変換器１００ａにおいて、圧電素子５０（圧電フィルム１０ａ）の電極層と振動板１０２とは電気的に接続されていないことが好ましい。
圧電素子５０の電極層と振動板１０２とが電気的に接続されると、ショートなどのトラブルが発生するおそれがある。従って、圧電素子５０の電極層と振動板１０２とが電気的に接続されていない構成とすることにより、故障の発生リスクを低減できる。 In addition, in theelectroacoustic transducer 100a, it is preferable that the electrode layer of the piezoelectric element 50 (piezoelectric film 10a) and the diaphragm 102 are not electrically connected.
If the electrode layer of thepiezoelectric element 50 and the diaphragm 102 are electrically connected, troubles such as short circuits may occur. Therefore, by configuring the electrode layer of the piezoelectric element 50 and the diaphragm 102 to be not electrically connected, the risk of occurrence of failure can be reduced.
圧電素子５０の電極層と振動板１０２とが電気的に接続されると、ショートなどのトラブルが発生するおそれがある。従って、圧電素子５０の電極層と振動板１０２とが電気的に接続されていない構成とすることにより、故障の発生リスクを低減できる。 In addition, in the
If the electrode layer of the
貼着層は、貼り合わせる際には流動性を有し、その後、固体になる、接着剤からなる層でも、貼り合わせる際にゲル状（ゴム状）の柔らかい固体で、その後もゲル状の状態が変化しない、粘着剤からなる層でも、接着剤と粘着剤との両方の特徴を持った材料からなる層でもよい。
The adhesive layer has fluidity when it is pasted and then becomes solid.Even a layer made of adhesive is a gel-like (rubber-like) soft solid when it is pasted and remains in a gel-like state after that. It may be a layer made of an adhesive that does not change, or a layer made of a material that has characteristics of both an adhesive and a pressure-sensitive adhesive.
ここで、電気音響変換器１００では、圧電素子５０を伸縮させることで、振動板１０２を撓ませ振動させて、音を発生させる。従って、電気音響変換器１００では、圧電素子５０の伸縮が、直接的に振動板１０２に伝達されるのが好ましい。振動板１０２と圧電素子５０との間に、振動を緩和するような粘性を有する物質が存在すると、振動板１０２への圧電素子５０の伸縮のエネルギーの伝達効率が低くなってしまい、電気音響変換器１００の駆動効率が低下してしまう。
この点を考慮すると、振動板と圧電素子（圧電フィルム）とを貼着する貼着層は、粘着剤からなる粘着剤層よりも、固体で硬い貼着層が得られる、接着剤からなる接着剤層であるのが好ましい。より好ましい貼着層としては、具体的には、ポリエステル系接着剤およびスチレン・ブタジエンゴム（ＳＢＲ）系接着剤等の熱可塑タイプの接着剤からなる貼着層が例示される。
接着は、粘着とは異なり、高い接着温度を求める際に有用である。また、熱可塑タイプの接着剤は『比較的低温、短時間、および、強接着』を兼ね備えており、好適である。 Here, in the electroacoustic transducer 100, by expanding and contracting thepiezoelectric element 50, the diaphragm 102 is bent and vibrated to generate sound. Therefore, in the electroacoustic transducer 100, it is preferable that the expansion and contraction of the piezoelectric element 50 be directly transmitted to the diaphragm 102. If a viscous substance that dampens vibration exists between the diaphragm 102 and the piezoelectric element 50, the efficiency of transmitting the energy of the expansion and contraction of the piezoelectric element 50 to the diaphragm 102 will decrease, resulting in electroacoustic conversion. As a result, the driving efficiency of the device 100 decreases.
Considering this point, the adhesive layer that adheres the diaphragm and the piezoelectric element (piezoelectric film) to the diaphragm and the piezoelectric element (piezoelectric film) is an adhesive layer that is made of an adhesive that provides a solid and harder adhesive layer than an adhesive layer that is made of an adhesive. Preferably, it is a layer of agent. More preferable adhesive layers include, specifically, adhesive layers made of thermoplastic adhesives such as polyester adhesives and styrene-butadiene rubber (SBR) adhesives.
Adhesion, unlike adhesion, is useful when a high bonding temperature is required. In addition, thermoplastic adhesives are suitable because they have "relatively low temperature, short time, and strong adhesion."
この点を考慮すると、振動板と圧電素子（圧電フィルム）とを貼着する貼着層は、粘着剤からなる粘着剤層よりも、固体で硬い貼着層が得られる、接着剤からなる接着剤層であるのが好ましい。より好ましい貼着層としては、具体的には、ポリエステル系接着剤およびスチレン・ブタジエンゴム（ＳＢＲ）系接着剤等の熱可塑タイプの接着剤からなる貼着層が例示される。
接着は、粘着とは異なり、高い接着温度を求める際に有用である。また、熱可塑タイプの接着剤は『比較的低温、短時間、および、強接着』を兼ね備えており、好適である。 Here, in the electroacoustic transducer 100, by expanding and contracting the
Considering this point, the adhesive layer that adheres the diaphragm and the piezoelectric element (piezoelectric film) to the diaphragm and the piezoelectric element (piezoelectric film) is an adhesive layer that is made of an adhesive that provides a solid and harder adhesive layer than an adhesive layer that is made of an adhesive. Preferably, it is a layer of agent. More preferable adhesive layers include, specifically, adhesive layers made of thermoplastic adhesives such as polyester adhesives and styrene-butadiene rubber (SBR) adhesives.
Adhesion, unlike adhesion, is useful when a high bonding temperature is required. In addition, thermoplastic adhesives are suitable because they have "relatively low temperature, short time, and strong adhesion."
貼着層の厚さには、制限はなく、貼着層の材料に応じて、十分な貼着力（接着力、粘着力）が得られる厚さを、適宜、設定すればよい。
ここで、電気音響変換器１００においては、貼着層が薄い方が、振動板１０２に伝達する圧電素子５０の伸縮エネルギー（振動エネルギー）の伝達効果を高くして、エネルギー効率を高くできる。また、貼着層が厚く剛性が高いと、圧電素子５０の伸縮を拘束する可能性もある。
この点を考慮すると、貼着層は、薄い方が好ましい。具体的には、貼着層の厚さは、貼着後の厚さで０．１～５０μｍが好ましく、０．１～３０μｍがより好ましく、０．１～１０μｍがさらに好ましい。 There is no limit to the thickness of the adhesive layer, and a thickness that provides sufficient adhesive strength (adhesive strength, adhesive strength) may be appropriately set depending on the material of the adhesive layer.
Here, in the electroacoustic transducer 100, the thinner the adhesive layer is, the higher the transmission effect of the elastic energy (vibration energy) of thepiezoelectric element 50 to the diaphragm 102 can be, and the higher the energy efficiency can be. Further, if the adhesive layer is thick and rigid, expansion and contraction of the piezoelectric element 50 may be restricted.
Considering this point, it is preferable that the adhesive layer be thinner. Specifically, the thickness of the adhesive layer after attachment is preferably 0.1 to 50 μm, more preferably 0.1 to 30 μm, even more preferably 0.1 to 10 μm.
ここで、電気音響変換器１００においては、貼着層が薄い方が、振動板１０２に伝達する圧電素子５０の伸縮エネルギー（振動エネルギー）の伝達効果を高くして、エネルギー効率を高くできる。また、貼着層が厚く剛性が高いと、圧電素子５０の伸縮を拘束する可能性もある。
この点を考慮すると、貼着層は、薄い方が好ましい。具体的には、貼着層の厚さは、貼着後の厚さで０．１～５０μｍが好ましく、０．１～３０μｍがより好ましく、０．１～１０μｍがさらに好ましい。 There is no limit to the thickness of the adhesive layer, and a thickness that provides sufficient adhesive strength (adhesive strength, adhesive strength) may be appropriately set depending on the material of the adhesive layer.
Here, in the electroacoustic transducer 100, the thinner the adhesive layer is, the higher the transmission effect of the elastic energy (vibration energy) of the
Considering this point, it is preferable that the adhesive layer be thinner. Specifically, the thickness of the adhesive layer after attachment is preferably 0.1 to 50 μm, more preferably 0.1 to 30 μm, even more preferably 0.1 to 10 μm.
なお、電気音響変換器１００において、貼着層は、好ましい態様として設けられるものであり、必須の構成要素ではない。
従って、電気音響変換器１００は、貼着層を有さず、公知の圧着手段、締結手段、および、固定手段等を用いて、振動板１０２と圧電素子５０とを固定してもよい。例えば、圧電素子５０の平面視の形状が矩形である場合には、四隅をボルトナットのような部材で締結して電気音響変換器を構成してもよく、または、四隅と中心部とをボルトナットのような部材で締結して電気音響変換器を構成してもよい。 Note that in the electroacoustic transducer 100, the adhesive layer is provided as a preferred embodiment and is not an essential component.
Therefore, the electroacoustic transducer 100 may not have an adhesive layer, and thediaphragm 102 and the piezoelectric element 50 may be fixed using known crimping means, fastening means, fixing means, or the like. For example, when the piezoelectric element 50 has a rectangular shape in plan view, the four corners may be fastened with members such as bolts and nuts to form an electroacoustic transducer, or the four corners and the center may be connected with bolts. The electroacoustic transducer may be configured by fastening with a member such as a nut.
従って、電気音響変換器１００は、貼着層を有さず、公知の圧着手段、締結手段、および、固定手段等を用いて、振動板１０２と圧電素子５０とを固定してもよい。例えば、圧電素子５０の平面視の形状が矩形である場合には、四隅をボルトナットのような部材で締結して電気音響変換器を構成してもよく、または、四隅と中心部とをボルトナットのような部材で締結して電気音響変換器を構成してもよい。 Note that in the electroacoustic transducer 100, the adhesive layer is provided as a preferred embodiment and is not an essential component.
Therefore, the electroacoustic transducer 100 may not have an adhesive layer, and the
しかしながら、この場合には、電源から駆動電圧を印加した際に、振動板１０２に対して圧電素子５０が独立して伸縮してしまい、場合によっては、圧電素子５０のみが撓んで、圧電素子５０の伸縮が振動板１０２に伝わらない。このように、振動板１０２に対して圧電素子５０が独立して伸縮した場合には、圧電素子５０による振動板１０２の振動効率が低下してしまい。振動板１０２を十分に振動させられなくなってしまう可能性がある。
この点を考慮すると、振動板１０２と圧電素子５０とは、貼着層で貼着するのが好ましい。 However, in this case, when a driving voltage is applied from the power source, thepiezoelectric element 50 expands and contracts independently with respect to the diaphragm 102, and in some cases, only the piezoelectric element 50 is bent, causing the piezoelectric element 50 to expansion and contraction is not transmitted to the diaphragm 102. In this way, when the piezoelectric element 50 expands and contracts independently with respect to the diaphragm 102, the vibration efficiency of the diaphragm 102 caused by the piezoelectric element 50 decreases. There is a possibility that the diaphragm 102 cannot be vibrated sufficiently.
Taking this point into consideration, it is preferable that thediaphragm 102 and the piezoelectric element 50 be attached using an adhesive layer.
この点を考慮すると、振動板１０２と圧電素子５０とは、貼着層で貼着するのが好ましい。 However, in this case, when a driving voltage is applied from the power source, the
Taking this point into consideration, it is preferable that the
次に、本発明の圧電フィルムの他の一例について図６を用いて説明する。
図６に示す圧電フィルム１０ｂは、矩形状の１枚の圧電フィルムである。図６では、図面を簡略化して、圧電素子５０の構成を明瞭に示すために、保護層の図示を省略している。図６に示す圧電フィルム１０ｂは、圧電体層２０中の未分極領域２０ｂの配置等が異なる以外は、図３に示す圧電フィルム１０ａと同様の構成を有する。 Next, another example of the piezoelectric film of the present invention will be described using FIG. 6.
Thepiezoelectric film 10b shown in FIG. 6 is a single rectangular piezoelectric film. In FIG. 6, illustration of the protective layer is omitted in order to simplify the drawing and clearly show the configuration of the piezoelectric element 50. The piezoelectric film 10b shown in FIG. 6 has the same configuration as the piezoelectric film 10a shown in FIG. 3, except that the arrangement of the unpolarized regions 20b in the piezoelectric layer 20 is different.
図６に示す圧電フィルム１０ｂは、矩形状の１枚の圧電フィルムである。図６では、図面を簡略化して、圧電素子５０の構成を明瞭に示すために、保護層の図示を省略している。図６に示す圧電フィルム１０ｂは、圧電体層２０中の未分極領域２０ｂの配置等が異なる以外は、図３に示す圧電フィルム１０ａと同様の構成を有する。 Next, another example of the piezoelectric film of the present invention will be described using FIG. 6.
The
図６に示す圧電フィルム１０ｂは、圧電体層２０の対向する端辺（図中左右の端辺）に沿った所定の幅の２つの領域が分極されていない未分極領域２０ｂであり、それ以外の領域、すなわち、図中左右方向の中央の領域は厚さ方向に分極された分極領域２０ａである。すなわち、未分極領域２０ｂは、圧電フィルム１０ｂの外縁部に存在している。
In the piezoelectric film 10b shown in FIG. 6, two regions of a predetermined width along the opposing edges (left and right edges in the figure) of the piezoelectric layer 20 are unpolarized regions 20b, and the other regions are unpolarized regions 20b. The region , that is, the center region in the left-right direction in the figure is a polarized region 20a polarized in the thickness direction. That is, the unpolarized region 20b exists at the outer edge of the piezoelectric film 10b.
このような圧電フィルム１０ｂは、図７に示すように、振動板１０２に貼り付けて電気音響変換器１００ｂとして用いることができる。
As shown in FIG. 7, such a piezoelectric film 10b can be attached to a diaphragm 102 and used as an electroacoustic transducer 100b.
ここで、前述のとおり、従来の圧電フィルムを振動板に貼り付けて電気音響変換器とした場合に、圧電フィルムの振動によって、振動板と圧電フィルムとの貼着が剥離するという問題があることがわかった。図１５に示す電気音響変換器２００ｂのように、従来の、圧電フィルム２１０の全域で圧電体層が分極された構成の場合には、図１５に矢印で示すように、圧電フィルム２１０の全域で伸縮（振動）する。このような構成の場合には、圧電フィルム２１０と振動板２０２との貼着面の端部に応力が集中し、端部から剥離が生じて、それが内側に進展していくことになる。
As mentioned above, when a conventional piezoelectric film is attached to a diaphragm to form an electroacoustic transducer, there is a problem in that the vibration of the piezoelectric film causes the bond between the diaphragm and the piezoelectric film to peel off. I understand. In the case of a conventional configuration in which the piezoelectric layer is polarized over the entire area of the piezoelectric film 210, as in the electroacoustic transducer 200b shown in FIG. 15, as shown by the arrow in FIG. Expands and contracts (vibrates). In the case of such a configuration, stress is concentrated at the end of the bonding surface between the piezoelectric film 210 and the diaphragm 202, and peeling occurs from the end and progresses inward.
これに対して、本発明の圧電フィルム１０ｂを有する電気音響変換器１００ｂにおいては、圧電フィルム１０ｂの外縁部に未分極領域２０ｂを有する。そのため、図７に矢印で示すように、圧電フィルム１０ｂは、圧電フィルム１０ｂの中央の領域で伸縮（振動）し、両端部の領域は伸縮（振動）しない。そのため、圧電フィルム１０ｂと振動板１０２との貼着面の端部に集中する応力を軽減でき、端部から剥離が生じることを抑制できる。
In contrast, the electroacoustic transducer 100b having the piezoelectric film 10b of the present invention has an unpolarized region 20b at the outer edge of the piezoelectric film 10b. Therefore, as shown by arrows in FIG. 7, the piezoelectric film 10b expands and contracts (vibrates) in the center region of the piezoelectric film 10b, but does not expand and contract (vibrates) in the regions at both ends. Therefore, it is possible to reduce the stress concentrated at the end of the bonding surface between the piezoelectric film 10b and the diaphragm 102, and it is possible to suppress the occurrence of peeling from the end.
なお、圧電フィルムと振動板との剥離を抑制する観点から、圧電フィルムにおける未分極領域の幅（近傍の端辺に直交する方向の幅）は、１ｍｍ以上が好ましく、３ｍｍ以上がより好ましく、１０ｍｍ以上がさらに好ましい。一方で、未分極領域が大きすぎると、圧電フィルムの出力が低下して、電気音響変換器の音圧が低下してしまう。そのため、圧電フィルムにおける未分極領域の幅は、圧電フィルムの幅の１０％以下が好ましく、５％以下がより好ましく、３％以下がさらに好ましい。
In addition, from the viewpoint of suppressing peeling between the piezoelectric film and the diaphragm, the width of the unpolarized region in the piezoelectric film (width in the direction perpendicular to the nearby edges) is preferably 1 mm or more, more preferably 3 mm or more, and 10 mm or more. The above is more preferable. On the other hand, if the unpolarized area is too large, the output of the piezoelectric film will decrease, and the sound pressure of the electroacoustic transducer will decrease. Therefore, the width of the unpolarized region in the piezoelectric film is preferably 10% or less of the width of the piezoelectric film, more preferably 5% or less, and even more preferably 3% or less.
また、図６に示す例では、平面視における圧電フィルム１０ｂの４つの端辺のうち対向する２つの端辺に沿って２つの未分極領域２０ｂを有する構成としたがこれに限定はされない。例えば、１つあるいは３つの端辺に沿って未分極領域２０ｂを有する構成であってもよいし、４つの端辺に沿って、すなわち、圧電フィルム１０ｂの外縁部の全域に未分極領域２０ｂを有していてもよい。
Further, in the example shown in FIG. 6, the piezoelectric film 10b has two unpolarized regions 20b along two opposing edges among the four edges in a plan view, but the present invention is not limited to this. For example, the configuration may include the unpolarized region 20b along one or three edges, or the unpolarized region 20b may be provided along the four edges, that is, over the entire outer edge of the piezoelectric film 10b. may have.
あるいは、図６に示す例では、圧電フィルム１０ｂの端辺に沿う方向の全域に未分極領域２０ｂを有する構成としたがこれに限定はされず、圧電フィルム１０ｂの端辺に沿う方向の一部の領域に未分極領域２０ｂを有する構成としてもよい。例えば、平面視における、圧電フィルム１０ｂの４つの角部の少なくとも１つに未分極領域２０ｂを有する構成としてもよい。
Alternatively, in the example shown in FIG. 6, the configuration is such that the unpolarized region 20b is provided in the entire area along the edge of the piezoelectric film 10b, but the structure is not limited to this, and a part of the area along the edge of the piezoelectric film 10b is used. It is also possible to have an unpolarized region 20b in the region. For example, the piezoelectric film 10b may have an unpolarized region 20b at at least one of its four corners in a plan view.
また、図７に示す例では、単層の圧電フィルム１０ｂを振動板１０２に貼着する構成としたがこれに限定はされない。例えば、図５に示すような圧電フィルム１０ａを複数回折り返して圧電フィルムを複数層積層した圧電素子５０において、振動板１０２と貼着される面側の圧電フィルム１０ａ（圧電体層２０）に未分極領域２０ｂを有する構成としてもよい。具体的には、図５において、圧電素子５０の、振動板１０２側（図中下側）の圧電フィルム１０ａの図中右側の端辺に沿って所定の幅の未分極領域２０ｂを有する構成とすることで、圧電素子５０と振動板１０２との貼着面の端部に応力集中が発生することを防止でき、端部から剥離が生じることを抑制できる。
Further, in the example shown in FIG. 7, the single-layer piezoelectric film 10b is attached to the diaphragm 102, but the present invention is not limited to this. For example, in a piezoelectric element 50 in which a piezoelectric film 10a is folded multiple times and multiple layers of piezoelectric films are laminated as shown in FIG. A configuration including a polarized region 20b may also be used. Specifically, in FIG. 5, the piezoelectric element 50 has an unpolarized region 20b of a predetermined width along the right edge of the piezoelectric film 10a on the diaphragm 102 side (lower side in the figure). By doing so, stress concentration can be prevented from occurring at the end portions of the bonding surfaces between the piezoelectric element 50 and the diaphragm 102, and peeling from the end portions can be suppressed.
なお、電気音響変換器１００ｂにおいても、圧電フィルム１０ｂの電極層と振動板１０２とは電気的に接続されていないことが好ましい。
Note that also in the electroacoustic transducer 100b, it is preferable that the electrode layer of the piezoelectric film 10b and the diaphragm 102 are not electrically connected.
また、図７に示す例では、圧電フィルム１０ｂの外縁部に未分極領域２０ｂを有する構成としたがこれに限定はされない。例えば、図５に示すような圧電フィルム１０ａを折り返してなる圧電素子５０において、振動板１０２と貼り付ける側の層の、折り返し側の端辺に沿う領域、すなわち、図５中、振動板１０２との貼着面の図中右側の端辺に沿う領域に未分極領域２０ｂを設けてもよい。この場合、圧電素子５０が有する圧電フィルム１０ａを折り返す前の状態において、未分極領域２０ｂは、圧電フィルム１０ａの外縁部以外の領域に形成される。
Furthermore, in the example shown in FIG. 7, the piezoelectric film 10b has an unpolarized region 20b at the outer edge thereof, but the present invention is not limited thereto. For example, in a piezoelectric element 50 formed by folding a piezoelectric film 10a as shown in FIG. An unpolarized region 20b may be provided in a region along the right edge in the figure of the adhesion surface. In this case, before the piezoelectric film 10a of the piezoelectric element 50 is folded back, the unpolarized region 20b is formed in a region other than the outer edge of the piezoelectric film 10a.
以下、本発明の圧電フィルムの構成要素について説明する。なお、以下の説明において、区別する必要がない場合には、圧電フィルム１０ａ～１０ｂをまとめて圧電フィルム１０ともいう。
Hereinafter, the constituent elements of the piezoelectric film of the present invention will be explained. In the following description, the piezoelectric films 10a to 10b are also collectively referred to as the piezoelectric film 10 unless it is necessary to distinguish them.
図８に、圧電フィルム１０の一部を拡大して示す。
図８に示す圧電フィルム１０は、圧電性を有するシート状物である圧電体層２０と、圧電体層２０の一方の面に積層される第２電極層２６と、第２電極層２６の圧電体層２０と反対側の面に積層される第２保護層３０と、圧電体層２０の他方の面に積層される第１電極層２４と、第１電極層２４の圧電体層２０と反対側の面に積層される第１保護層２８と、を有する。すなわち、圧電フィルム１０は、圧電体層２０を電極層で挟持し、電極層の圧電体層が接触していない面に保護層が積層された構成を有する。 FIG. 8 shows a part of thepiezoelectric film 10 in an enlarged manner.
Thepiezoelectric film 10 shown in FIG. A second protective layer 30 laminated on the surface opposite to the body layer 20 , a first electrode layer 24 laminated on the other surface of the piezoelectric layer 20 , and a layer opposite to the piezoelectric layer 20 of the first electrode layer 24 A first protective layer 28 is laminated on the side surface. That is, the piezoelectric film 10 has a structure in which the piezoelectric layer 20 is sandwiched between electrode layers, and a protective layer is laminated on the surface of the electrode layer that is not in contact with the piezoelectric layer.
図８に示す圧電フィルム１０は、圧電性を有するシート状物である圧電体層２０と、圧電体層２０の一方の面に積層される第２電極層２６と、第２電極層２６の圧電体層２０と反対側の面に積層される第２保護層３０と、圧電体層２０の他方の面に積層される第１電極層２４と、第１電極層２４の圧電体層２０と反対側の面に積層される第１保護層２８と、を有する。すなわち、圧電フィルム１０は、圧電体層２０を電極層で挟持し、電極層の圧電体層が接触していない面に保護層が積層された構成を有する。 FIG. 8 shows a part of the
The
本発明において、圧電体層２０は、図８に概念的に示すように、高分子材料を含むマトリックス３４中に、圧電体粒子３６を含む、高分子複合圧電体である。
In the present invention, the piezoelectric layer 20 is a polymer composite piezoelectric material containing piezoelectric particles 36 in a matrix 34 containing a polymer material, as conceptually shown in FIG.
圧電体層２０を構成する高分子複合圧電体のマトリックス３４（マトリックス兼バインダ）の材料として、常温で粘弾性を有する高分子材料を用いるのが好ましい。なお、本明細書において、「常温」とは、０～５０℃程度の温度域を指す。
As the material for the matrix 34 (matrix and binder) of the polymer composite piezoelectric material constituting the piezoelectric layer 20, it is preferable to use a polymer material that has viscoelasticity at room temperature. Note that in this specification, "normal temperature" refers to a temperature range of about 0 to 50°C.
ここで、高分子複合圧電体（圧電体層２０）は、次の用件を具備したものであるのが好ましい。
（ｉ） 可撓性
例えば、携帯用として新聞や雑誌のように書類感覚で緩く撓めた状態で把持する場合、絶えず外部から、数Ｈｚ以下の比較的ゆっくりとした、大きな曲げ変形を受けることになる。この時、高分子複合圧電体が硬いと、その分大きな曲げ応力が発生し、高分子マトリックスと圧電体粒子との界面で亀裂が発生し、やがて破壊に繋がる恐れがある。従って、高分子複合圧電体には適度な柔らかさが求められる。また、歪みエネルギーを熱として外部へ拡散できれば応力を緩和することができる。従って、高分子複合圧電体の損失正接が適度に大きいことが求められる。 Here, the polymer composite piezoelectric material (piezoelectric layer 20) preferably satisfies the following requirements.
(i) Flexibility For example, when holding a newspaper or magazine in a loosely bent state like a document for portable use, it is constantly subjected to relatively slow and large bending deformation of several Hz or less from the outside. become. At this time, if the polymer composite piezoelectric material is hard, a correspondingly large bending stress will be generated, and cracks will occur at the interface between the polymer matrix and the piezoelectric particles, which may eventually lead to destruction. Therefore, a polymer composite piezoelectric material is required to have appropriate softness. Moreover, if strain energy can be diffused to the outside as heat, stress can be alleviated. Therefore, the loss tangent of the polymer composite piezoelectric material is required to be appropriately large.
（ｉ） 可撓性
例えば、携帯用として新聞や雑誌のように書類感覚で緩く撓めた状態で把持する場合、絶えず外部から、数Ｈｚ以下の比較的ゆっくりとした、大きな曲げ変形を受けることになる。この時、高分子複合圧電体が硬いと、その分大きな曲げ応力が発生し、高分子マトリックスと圧電体粒子との界面で亀裂が発生し、やがて破壊に繋がる恐れがある。従って、高分子複合圧電体には適度な柔らかさが求められる。また、歪みエネルギーを熱として外部へ拡散できれば応力を緩和することができる。従って、高分子複合圧電体の損失正接が適度に大きいことが求められる。 Here, the polymer composite piezoelectric material (piezoelectric layer 20) preferably satisfies the following requirements.
(i) Flexibility For example, when holding a newspaper or magazine in a loosely bent state like a document for portable use, it is constantly subjected to relatively slow and large bending deformation of several Hz or less from the outside. become. At this time, if the polymer composite piezoelectric material is hard, a correspondingly large bending stress will be generated, and cracks will occur at the interface between the polymer matrix and the piezoelectric particles, which may eventually lead to destruction. Therefore, a polymer composite piezoelectric material is required to have appropriate softness. Moreover, if strain energy can be diffused to the outside as heat, stress can be alleviated. Therefore, the loss tangent of the polymer composite piezoelectric material is required to be appropriately large.
以上をまとめると、エキサイターとして用いるフレキシブルな高分子複合圧電体は、２０Ｈｚ～２０ｋＨｚの振動に対しては硬く、数Ｈｚ以下の振動に対しては柔らかく振る舞うことが求められる。また、高分子複合圧電体の損失正接は、２０ｋＨｚ以下の全ての周波数の振動に対して、適度に大きいことが求められる。
さらに、貼り付ける相手材（振動板）の剛性（硬さ、コシ、バネ定数）に合わせて、積層することで、簡便にバネ定数を調節できるのが好ましく、その際、貼着層１０４は薄ければ薄いほど、エネルギー効率を高めることができる。 To summarize the above, a flexible polymer composite piezoelectric material used as an exciter is required to behave hard against vibrations of 20 Hz to 20 kHz, and to behave softly against vibrations of several Hz or less. Further, the loss tangent of the polymer composite piezoelectric material is required to be appropriately large for vibrations of all frequencies below 20 kHz.
Furthermore, it is preferable that the spring constant can be easily adjusted by laminating layers according to the rigidity (hardness, stiffness, spring constant) of the mating material (diaphragm) to which the adhesive layer 104 is attached. The thinner it is, the more energy efficient it can be.
さらに、貼り付ける相手材（振動板）の剛性（硬さ、コシ、バネ定数）に合わせて、積層することで、簡便にバネ定数を調節できるのが好ましく、その際、貼着層１０４は薄ければ薄いほど、エネルギー効率を高めることができる。 To summarize the above, a flexible polymer composite piezoelectric material used as an exciter is required to behave hard against vibrations of 20 Hz to 20 kHz, and to behave softly against vibrations of several Hz or less. Further, the loss tangent of the polymer composite piezoelectric material is required to be appropriately large for vibrations of all frequencies below 20 kHz.
Furthermore, it is preferable that the spring constant can be easily adjusted by laminating layers according to the rigidity (hardness, stiffness, spring constant) of the mating material (diaphragm) to which the adhesive layer 104 is attached. The thinner it is, the more energy efficient it can be.
一般に、高分子固体は粘弾性緩和機構を有しており、温度上昇あるいは周波数の低下とともに大きなスケールの分子運動が貯蔵弾性率（ヤング率）の低下（緩和）あるいは損失弾性率の極大（吸収）として観測される。その中でも、非晶質領域の分子鎖のミクロブラウン運動によって引き起こされる緩和は、主分散と呼ばれ、非常に大きな緩和現象が見られる。この主分散が起きる温度がガラス転移点（Ｔｇ）であり、最も粘弾性緩和機構が顕著に現れる。
高分子複合圧電体（圧電体層２０）において、ガラス転移点が常温にある高分子材料、言い換えると、常温で粘弾性を有する高分子材料をマトリックスに用いることで、２０Ｈｚ～２０ｋＨｚの振動に対しては硬く、数Ｈｚ以下の遅い振動に対しては柔らかく振舞う高分子複合圧電体が実現する。特に、この振舞いが好適に発現する等の点で、周波数１Ｈｚでのガラス転移点が常温、すなわち、０～５０℃にある高分子材料を、高分子複合圧電体のマトリックスに用いるのが好ましい。 In general, polymer solids have a viscoelastic relaxation mechanism, and as the temperature increases or the frequency decreases, large-scale molecular motion causes a decrease (relaxation) in the storage modulus (Young's modulus) or a maximum in the loss modulus (absorption). It is observed as Among these, the relaxation caused by micro-Brownian motion of molecular chains in the amorphous region is called principal dispersion, and a very large relaxation phenomenon is observed. The temperature at which this main dispersion occurs is the glass transition point (Tg), and the viscoelastic relaxation mechanism appears most prominently.
In the polymer composite piezoelectric material (piezoelectric layer 20), by using a polymer material whose glass transition point is at room temperature, in other words, a polymer material that has viscoelasticity at room temperature, for the matrix, it can withstand vibrations of 20Hz to 20kHz. This results in a polymer composite piezoelectric material that is hard and behaves softly when subjected to slow vibrations of several Hz or less. In particular, in order to suitably exhibit this behavior, it is preferable to use a polymer material whose glass transition point at a frequency of 1 Hz is at room temperature, that is, 0 to 50° C., for the matrix of the polymer composite piezoelectric material.
高分子複合圧電体（圧電体層２０）において、ガラス転移点が常温にある高分子材料、言い換えると、常温で粘弾性を有する高分子材料をマトリックスに用いることで、２０Ｈｚ～２０ｋＨｚの振動に対しては硬く、数Ｈｚ以下の遅い振動に対しては柔らかく振舞う高分子複合圧電体が実現する。特に、この振舞いが好適に発現する等の点で、周波数１Ｈｚでのガラス転移点が常温、すなわち、０～５０℃にある高分子材料を、高分子複合圧電体のマトリックスに用いるのが好ましい。 In general, polymer solids have a viscoelastic relaxation mechanism, and as the temperature increases or the frequency decreases, large-scale molecular motion causes a decrease (relaxation) in the storage modulus (Young's modulus) or a maximum in the loss modulus (absorption). It is observed as Among these, the relaxation caused by micro-Brownian motion of molecular chains in the amorphous region is called principal dispersion, and a very large relaxation phenomenon is observed. The temperature at which this main dispersion occurs is the glass transition point (Tg), and the viscoelastic relaxation mechanism appears most prominently.
In the polymer composite piezoelectric material (piezoelectric layer 20), by using a polymer material whose glass transition point is at room temperature, in other words, a polymer material that has viscoelasticity at room temperature, for the matrix, it can withstand vibrations of 20Hz to 20kHz. This results in a polymer composite piezoelectric material that is hard and behaves softly when subjected to slow vibrations of several Hz or less. In particular, in order to suitably exhibit this behavior, it is preferable to use a polymer material whose glass transition point at a frequency of 1 Hz is at room temperature, that is, 0 to 50° C., for the matrix of the polymer composite piezoelectric material.
常温で粘弾性を有する高分子材料としては、公知の各種のものが利用可能である。好ましくは、常温、すなわち０～５０℃において、動的粘弾性試験による周波数１Ｈｚにおける損失正接Ｔａｎδの極大値が、０．５以上有る高分子材料を用いる。
これにより、高分子複合圧電体が外力によってゆっくりと曲げられた際に、最大曲げモーメント部における高分子マトリックスと圧電体粒子との界面の応力集中が緩和され、高い可撓性が期待できる。 Various known polymer materials can be used as the polymer material having viscoelasticity at room temperature. Preferably, a polymer material having a maximum value of loss tangent Tan δ of 0.5 or more at a frequency of 1 Hz in a dynamic viscoelasticity test at room temperature, ie, 0 to 50° C., is used.
As a result, when the polymer composite piezoelectric material is slowly bent by an external force, stress concentration at the interface between the polymer matrix and the piezoelectric particles at the maximum bending moment portion is alleviated, and high flexibility can be expected.
これにより、高分子複合圧電体が外力によってゆっくりと曲げられた際に、最大曲げモーメント部における高分子マトリックスと圧電体粒子との界面の応力集中が緩和され、高い可撓性が期待できる。 Various known polymer materials can be used as the polymer material having viscoelasticity at room temperature. Preferably, a polymer material having a maximum value of loss tangent Tan δ of 0.5 or more at a frequency of 1 Hz in a dynamic viscoelasticity test at room temperature, ie, 0 to 50° C., is used.
As a result, when the polymer composite piezoelectric material is slowly bent by an external force, stress concentration at the interface between the polymer matrix and the piezoelectric particles at the maximum bending moment portion is alleviated, and high flexibility can be expected.
また、常温で粘弾性を有する高分子材料は、動的粘弾性測定による周波数１Ｈｚでの貯蔵弾性率（Ｅ’）が、０℃において１００ＭＰａ以上、５０℃において１０ＭＰａ以下、であるのが好ましい。
これにより、高分子複合圧電体が外力によってゆっくりと曲げられた際に発生する曲げモーメントが低減できると同時に、２０Ｈｚ～２０ｋＨｚの音響振動に対しては硬く振る舞うことができる。 Further, the polymer material having viscoelasticity at room temperature preferably has a storage modulus (E') at a frequency of 1 Hz measured by dynamic viscoelasticity measurement of 100 MPa or more at 0°C and 10 MPa or less at 50°C.
As a result, the bending moment that occurs when the polymer composite piezoelectric material is slowly bent by an external force can be reduced, and at the same time, it can behave stiffly against acoustic vibrations of 20 Hz to 20 kHz.
これにより、高分子複合圧電体が外力によってゆっくりと曲げられた際に発生する曲げモーメントが低減できると同時に、２０Ｈｚ～２０ｋＨｚの音響振動に対しては硬く振る舞うことができる。 Further, the polymer material having viscoelasticity at room temperature preferably has a storage modulus (E') at a frequency of 1 Hz measured by dynamic viscoelasticity measurement of 100 MPa or more at 0°C and 10 MPa or less at 50°C.
As a result, the bending moment that occurs when the polymer composite piezoelectric material is slowly bent by an external force can be reduced, and at the same time, it can behave stiffly against acoustic vibrations of 20 Hz to 20 kHz.
また、常温で粘弾性を有する高分子材料は、比誘電率が２５℃において１０以上有ると、より好適である。これにより、高分子複合圧電体に電圧を印加した際に、マトリックス中の圧電体粒子にはより高い電界が掛かるため、大きな変形量が期待できる。
しかしながら、その反面、良好な耐湿性の確保等を考慮すると、高分子材料は、比誘電率が２５℃において１０以下であるのも、好適である。 Further, it is more preferable that the polymer material having viscoelasticity at room temperature has a dielectric constant of 10 or more at 25°C. As a result, when a voltage is applied to the polymer composite piezoelectric material, a higher electric field is applied to the piezoelectric particles in the matrix, so a large amount of deformation can be expected.
However, on the other hand, in consideration of securing good moisture resistance, etc., it is also suitable for the polymer material to have a dielectric constant of 10 or less at 25°C.
しかしながら、その反面、良好な耐湿性の確保等を考慮すると、高分子材料は、比誘電率が２５℃において１０以下であるのも、好適である。 Further, it is more preferable that the polymer material having viscoelasticity at room temperature has a dielectric constant of 10 or more at 25°C. As a result, when a voltage is applied to the polymer composite piezoelectric material, a higher electric field is applied to the piezoelectric particles in the matrix, so a large amount of deformation can be expected.
However, on the other hand, in consideration of securing good moisture resistance, etc., it is also suitable for the polymer material to have a dielectric constant of 10 or less at 25°C.
このような条件を満たす常温で粘弾性を有する高分子材料としては、シアノエチル化ポリビニルアルコール（シアノエチル化ＰＶＡ）、ポリ酢酸ビニル、ポリビニリデンクロライドコアクリロニトリル、ポリスチレン－ビニルポリイソプレンブロック共重合体、ポリビニルメチルケトン、および、ポリブチルメタクリレート等が例示される。また、これらの高分子材料としては、ハイブラー５１２７（クラレ社製）などの市販品も、好適に利用可能である。なかでも、高分子材料としては，シアノエチル基を有する材料を用いることが好ましく、シアノエチル化ＰＶＡを用いるのが特に好ましい。
Examples of polymeric materials that have viscoelasticity at room temperature that meet these conditions include cyanoethylated polyvinyl alcohol (cyanoethylated PVA), polyvinyl acetate, polyvinylidene chloride core acrylonitrile, polystyrene-vinyl polyisoprene block copolymer, and polyvinyl methyl. Examples include ketones and polybutyl methacrylate. Furthermore, commercially available products such as Hybler 5127 (manufactured by Kuraray Co., Ltd.) can also be suitably used as these polymeric materials. Among these, as the polymer material, it is preferable to use a material having a cyanoethyl group, and it is particularly preferable to use cyanoethylated PVA.
常温で粘弾性を有する高分子材料としては、シアノエチル基を有する高分子材料を用いるのが好ましく、シアノエチル化ＰＶＡを用いるのが特に好ましい。すなわち、本発明において、圧電体層２０は、マトリックス３４として、シアノエチル基を有する高分子材料を用いるのが好ましく、シアノエチル化ＰＶＡを用いるのが特に好ましい。
以下の説明では、シアノエチル化ＰＶＡを代表とする上述の高分子材料を、まとめて『常温で粘弾性を有する高分子材料』とも言う。 As the polymeric material having viscoelasticity at room temperature, it is preferable to use a polymeric material having a cyanoethyl group, and it is particularly preferable to use cyanoethylated PVA. That is, in the present invention, it is preferable for thepiezoelectric layer 20 to use a polymeric material having a cyanoethyl group as the matrix 34, and it is particularly preferable to use cyanoethylated PVA.
In the following explanation, the above-mentioned polymeric materials represented by cyanoethylated PVA are also collectively referred to as "polymeric materials having viscoelasticity at room temperature."
以下の説明では、シアノエチル化ＰＶＡを代表とする上述の高分子材料を、まとめて『常温で粘弾性を有する高分子材料』とも言う。 As the polymeric material having viscoelasticity at room temperature, it is preferable to use a polymeric material having a cyanoethyl group, and it is particularly preferable to use cyanoethylated PVA. That is, in the present invention, it is preferable for the
In the following explanation, the above-mentioned polymeric materials represented by cyanoethylated PVA are also collectively referred to as "polymeric materials having viscoelasticity at room temperature."
なお、これらの常温で粘弾性を有する高分子材料は、１種のみを用いてもよく、複数種を併用（混合）して用いてもよい。
Note that these polymeric materials having viscoelasticity at room temperature may be used alone or in combination (mixture) of multiple types.
このような常温で粘弾性を有する高分子材料を用いるマトリックス３４は、必要に応じて、複数の高分子材料を併用してもよい。
すなわち、マトリックス３４には、誘電特性や機械特性の調節等を目的として、シアノエチル化ＰＶＡ等の粘弾性材料に加え、必要に応じて、その他の誘電性高分子材料を添加しても良い。 Thematrix 34 using such a polymeric material having viscoelasticity at room temperature may be made of a plurality of polymeric materials in combination, if necessary.
That is, in addition to the viscoelastic material such as cyanoethylated PVA, other dielectric polymeric materials may be added to thematrix 34 as necessary for the purpose of adjusting dielectric properties and mechanical properties.
すなわち、マトリックス３４には、誘電特性や機械特性の調節等を目的として、シアノエチル化ＰＶＡ等の粘弾性材料に加え、必要に応じて、その他の誘電性高分子材料を添加しても良い。 The
That is, in addition to the viscoelastic material such as cyanoethylated PVA, other dielectric polymeric materials may be added to the
添加可能な誘電性高分子材料としては、一例として、ポリフッ化ビニリデン、フッ化ビニリデン－テトラフルオロエチレン共重合体、フッ化ビニリデン－トリフルオロエチレン共重合体、ポリフッ化ビニリデン－トリフルオロエチレン共重合体およびポリフッ化ビニリデン－テトラフルオロエチレン共重合体等のフッ素系高分子、シアン化ビニリデン－酢酸ビニル共重合体、シアノエチルセルロース、シアノエチルヒドロキシサッカロース、シアノエチルヒドロキシセルロース、シアノエチルヒドロキシプルラン、シアノエチルメタクリレート、シアノエチルアクリレート、シアノエチルヒドロキシエチルセルロース、シアノエチルアミロース、シアノエチルヒドロキシプロピルセルロース、シアノエチルジヒドロキシプロピルセルロース、シアノエチルヒドロキシプロピルアミロース、シアノエチルポリアクリルアミド、シアノエチルポリアクリレート、シアノエチルプルラン、シアノエチルポリヒドロキシメチレン、シアノエチルグリシドールプルラン、シアノエチルサッカロースおよびシアノエチルソルビトール等のシアノ基またはシアノエチル基を有するポリマー、ならびに、ニトリルゴムやクロロプレンゴム等の合成ゴム等が例示される。
中でも、シアノエチル基を有する高分子材料は、好適に利用される。
また、圧電体層２０のマトリックス３４において、これらの誘電性高分子材料は、１種に限定はされず、複数種を添加してもよい。 Examples of dielectric polymer materials that can be added include polyvinylidene fluoride, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-trifluoroethylene copolymer, and polyvinylidene fluoride-trifluoroethylene copolymer. and fluorine-based polymers such as polyvinylidene fluoride-tetrafluoroethylene copolymer, vinylidene cyanide-vinyl acetate copolymer, cyanoethylcellulose, cyanoethylhydroxysucrose, cyanoethylhydroxycellulose, cyanoethylhydroxypullulan, cyanoethyl methacrylate, cyanoethyl acrylate, cyanoethyl Cyano groups such as hydroxyethyl cellulose, cyanoethyl amylose, cyanoethyl hydroxypropyl cellulose, cyanoethyl dihydroxypropyl cellulose, cyanoethyl hydroxypropyl amylose, cyanoethyl polyacrylamide, cyanoethyl polyacrylate, cyanoethyl pullulan, cyanoethyl polyhydroxymethylene, cyanoethyl glycidol pullulan, cyanoethyl saccharose and cyanoethyl sorbitol Examples include polymers having a cyanoethyl group, and synthetic rubbers such as nitrile rubber and chloroprene rubber.
Among them, polymeric materials having cyanoethyl groups are preferably used.
Further, in thematrix 34 of the piezoelectric layer 20, the number of these dielectric polymer materials is not limited to one type, and a plurality of types may be added.
中でも、シアノエチル基を有する高分子材料は、好適に利用される。
また、圧電体層２０のマトリックス３４において、これらの誘電性高分子材料は、１種に限定はされず、複数種を添加してもよい。 Examples of dielectric polymer materials that can be added include polyvinylidene fluoride, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-trifluoroethylene copolymer, and polyvinylidene fluoride-trifluoroethylene copolymer. and fluorine-based polymers such as polyvinylidene fluoride-tetrafluoroethylene copolymer, vinylidene cyanide-vinyl acetate copolymer, cyanoethylcellulose, cyanoethylhydroxysucrose, cyanoethylhydroxycellulose, cyanoethylhydroxypullulan, cyanoethyl methacrylate, cyanoethyl acrylate, cyanoethyl Cyano groups such as hydroxyethyl cellulose, cyanoethyl amylose, cyanoethyl hydroxypropyl cellulose, cyanoethyl dihydroxypropyl cellulose, cyanoethyl hydroxypropyl amylose, cyanoethyl polyacrylamide, cyanoethyl polyacrylate, cyanoethyl pullulan, cyanoethyl polyhydroxymethylene, cyanoethyl glycidol pullulan, cyanoethyl saccharose and cyanoethyl sorbitol Examples include polymers having a cyanoethyl group, and synthetic rubbers such as nitrile rubber and chloroprene rubber.
Among them, polymeric materials having cyanoethyl groups are preferably used.
Further, in the
また、マトリックス３４には、誘電性高分子材料以外にも、ガラス転移点Ｔｇを調節する目的で、塩化ビニル樹脂、ポリエチレン、ポリスチレン、メタクリル樹脂、ポリブテン、および、イソブチレン等の熱可塑性樹脂、ならびに、フェノール樹脂、尿素樹脂、メラミン樹脂、アルキド樹脂、および、マイカ等の熱硬化性樹脂を添加しても良い。
さらに、粘着性を向上する目的で、ロジンエステル、ロジン、テルペン、テルペンフェノール、および、石油樹脂等の粘着付与剤を添加しても良い。 In addition to the dielectric polymer material, thematrix 34 also includes thermoplastic resins such as vinyl chloride resin, polyethylene, polystyrene, methacrylic resin, polybutene, and isobutylene, for the purpose of adjusting the glass transition point Tg, and Thermosetting resins such as phenol resins, urea resins, melamine resins, alkyd resins, and mica may also be added.
Furthermore, for the purpose of improving tackiness, tackifiers such as rosin ester, rosin, terpene, terpene phenol, and petroleum resin may be added.
さらに、粘着性を向上する目的で、ロジンエステル、ロジン、テルペン、テルペンフェノール、および、石油樹脂等の粘着付与剤を添加しても良い。 In addition to the dielectric polymer material, the
Furthermore, for the purpose of improving tackiness, tackifiers such as rosin ester, rosin, terpene, terpene phenol, and petroleum resin may be added.
圧電体層２０のマトリックス３４において、シアノエチル化ＰＶＡ等の粘弾性を有する高分子材料以外の材料を添加する際の添加量には、特に限定は無いが、マトリックス３４に占める割合で３０質量％以下とするのが好ましい。
これにより、マトリックス３４における粘弾性緩和機構を損なうことなく、添加する高分子材料の特性を発現できるため、高誘電率化、耐熱性の向上、圧電体粒子３６および電極層との密着性向上等の点で好ましい結果を得ることができる。 In thematrix 34 of the piezoelectric layer 20, when adding a material other than a viscoelastic polymeric material such as cyanoethylated PVA, there is no particular limitation on the amount added, but the proportion in the matrix 34 is 30% by mass or less. It is preferable that
This allows the properties of the added polymer material to be expressed without impairing the viscoelastic relaxation mechanism in thematrix 34, resulting in higher dielectric constant, improved heat resistance, improved adhesion between the piezoelectric particles 36 and the electrode layer, etc. Favorable results can be obtained in this respect.
これにより、マトリックス３４における粘弾性緩和機構を損なうことなく、添加する高分子材料の特性を発現できるため、高誘電率化、耐熱性の向上、圧電体粒子３６および電極層との密着性向上等の点で好ましい結果を得ることができる。 In the
This allows the properties of the added polymer material to be expressed without impairing the viscoelastic relaxation mechanism in the
圧電体層２０は、このようなマトリックス３４に、圧電体粒子３６を含む、高分子複合圧電体からなる層である。圧電体粒子３６は、マトリックス３４に分散されている。好ましくは、圧電体粒子３６は、マトリックス３４に均一（略均一）に分散される。
圧電体粒子３６は、ペロブスカイト型またはウルツ鉱型の結晶構造を有するセラミックス粒子からなるものである。
圧電体粒子３６を構成するセラミックス粒子としては、例えば、チタン酸ジルコン酸鉛（ＰＺＴ）、チタン酸ジルコン酸ランタン酸鉛（ＰＬＺＴ）、チタン酸バリウム（ＢａＴｉＯ3）、酸化亜鉛（ＺｎＯ）、および、チタン酸バリウムとビスマスフェライト（ＢｉＦｅ3）との固溶体（ＢＦＢＴ）等が例示される。 Thepiezoelectric layer 20 is a layer made of a polymer composite piezoelectric material that includes such a matrix 34 and piezoelectric particles 36 . Piezoelectric particles 36 are dispersed in matrix 34 . Preferably, the piezoelectric particles 36 are uniformly (substantially uniformly) dispersed in the matrix 34.
Thepiezoelectric particles 36 are made of ceramic particles having a perovskite or wurtzite crystal structure.
Examples of the ceramic particles constituting thepiezoelectric particles 36 include lead zirconate titanate (PZT), lead lanthanate zirconate titanate (PLZT), barium titanate (BaTiO 3 ), zinc oxide (ZnO), and A solid solution (BFBT) of barium titanate and bismuth ferrite (BiFe 3 ) is exemplified.
圧電体粒子３６は、ペロブスカイト型またはウルツ鉱型の結晶構造を有するセラミックス粒子からなるものである。
圧電体粒子３６を構成するセラミックス粒子としては、例えば、チタン酸ジルコン酸鉛（ＰＺＴ）、チタン酸ジルコン酸ランタン酸鉛（ＰＬＺＴ）、チタン酸バリウム（ＢａＴｉＯ3）、酸化亜鉛（ＺｎＯ）、および、チタン酸バリウムとビスマスフェライト（ＢｉＦｅ3）との固溶体（ＢＦＢＴ）等が例示される。 The
The
Examples of the ceramic particles constituting the
このような圧電体粒子３６の粒径には制限はなく、圧電フィルム１０のサイズ、および、圧電素子５０の用途等に応じて、適宜、選択すれば良い。圧電体粒子３６の粒径は、１～１０μｍが好ましい。
圧電体粒子３６の粒径をこの範囲とすることにより、圧電フィルム１０が高い圧電特性とフレキシビリティとを両立できる等の点で好ましい結果を得ることができる。 There is no limit to the particle size of thepiezoelectric particles 36, and it may be selected as appropriate depending on the size of the piezoelectric film 10, the use of the piezoelectric element 50, and the like. The particle size of the piezoelectric particles 36 is preferably 1 to 10 μm.
By setting the particle size of thepiezoelectric particles 36 within this range, favorable results can be obtained in that the piezoelectric film 10 can have both high piezoelectric properties and flexibility.
圧電体粒子３６の粒径をこの範囲とすることにより、圧電フィルム１０が高い圧電特性とフレキシビリティとを両立できる等の点で好ましい結果を得ることができる。 There is no limit to the particle size of the
By setting the particle size of the
なお、圧電体層２０中の圧電体粒子３６は、マトリックス３４中に、均一かつ規則性を持って分散されていてもよいし、均一に分散されていれば、マトリックス３４中に不規則に分散されていてもよい。
Note that the piezoelectric particles 36 in the piezoelectric layer 20 may be uniformly and regularly dispersed in the matrix 34, or if they are uniformly dispersed, they may be irregularly dispersed in the matrix 34. may have been done.
圧電フィルム１０において、圧電体層２０中におけるマトリックス３４と圧電体粒子３６との量比には、制限はなく、圧電フィルム１０の面方向の大きさおよび厚さ、圧電素子５０の用途、ならびに、圧電素子５０に要求される特性等に応じて、適宜、設定すればよい。
圧電体層２０中における圧電体粒子３６の体積分率は、３０～８０％が好ましく、５０％以上がより好ましく、従って、５０～８０％とするのが、さらに好ましい。
マトリックス３４と圧電体粒子３６との量比を上記範囲とすることにより、高い圧電特性とフレキシビリティとを両立できる等の点で好ましい結果を得ることができる。 In thepiezoelectric film 10, the ratio of the matrix 34 to the piezoelectric particles 36 in the piezoelectric layer 20 is not limited, and depends on the size and thickness of the piezoelectric film 10 in the plane direction, the use of the piezoelectric element 50, and It may be set as appropriate depending on the characteristics etc. required of the piezoelectric element 50.
The volume fraction of thepiezoelectric particles 36 in the piezoelectric layer 20 is preferably 30 to 80%, more preferably 50% or more, and therefore even more preferably 50 to 80%.
By setting the quantity ratio of thematrix 34 to the piezoelectric particles 36 within the above range, favorable results can be obtained in terms of achieving both high piezoelectric properties and flexibility.
圧電体層２０中における圧電体粒子３６の体積分率は、３０～８０％が好ましく、５０％以上がより好ましく、従って、５０～８０％とするのが、さらに好ましい。
マトリックス３４と圧電体粒子３６との量比を上記範囲とすることにより、高い圧電特性とフレキシビリティとを両立できる等の点で好ましい結果を得ることができる。 In the
The volume fraction of the
By setting the quantity ratio of the
圧電フィルム１０において、圧電体層２０の厚さには、特に限定はなく、圧電素子５０の用途、圧電素子５０における圧電フィルムの積層数、圧電フィルム１０に要求される特性等に応じて、適宜、設定すればよい。
圧電体層２０が厚いほど、いわゆるシート状物のコシの強さなどの剛性等の点では有利であるが、同じ量だけ圧電フィルム１０を伸縮させるために必要な電圧（電位差）は大きくなる。
圧電体層２０の厚さは、１０～３００μｍが好ましく、２０～２００μｍがより好ましく、３０～１５０μｍがさらに好ましい。
圧電体層２０の厚さを、上記範囲とすることにより、剛性の確保と適度な柔軟性との両立等の点で好ましい結果を得ることができる。 In thepiezoelectric film 10, the thickness of the piezoelectric layer 20 is not particularly limited, and may be determined as appropriate depending on the use of the piezoelectric element 50, the number of laminated piezoelectric films in the piezoelectric element 50, the characteristics required of the piezoelectric film 10, etc. , just set it.
The thicker thepiezoelectric layer 20 is, the more advantageous it is in terms of rigidity such as the stiffness of the so-called sheet-like material, but the voltage (potential difference) required to expand and contract the piezoelectric film 10 by the same amount increases.
The thickness of thepiezoelectric layer 20 is preferably 10 to 300 μm, more preferably 20 to 200 μm, and even more preferably 30 to 150 μm.
By setting the thickness of thepiezoelectric layer 20 within the above range, favorable results can be obtained in terms of ensuring both rigidity and appropriate flexibility.
圧電体層２０が厚いほど、いわゆるシート状物のコシの強さなどの剛性等の点では有利であるが、同じ量だけ圧電フィルム１０を伸縮させるために必要な電圧（電位差）は大きくなる。
圧電体層２０の厚さは、１０～３００μｍが好ましく、２０～２００μｍがより好ましく、３０～１５０μｍがさらに好ましい。
圧電体層２０の厚さを、上記範囲とすることにより、剛性の確保と適度な柔軟性との両立等の点で好ましい結果を得ることができる。 In the
The thicker the
The thickness of the
By setting the thickness of the
また、圧電体層２０は、厚さ方向に分極処理（ポーリング）されているのが好ましい。
Furthermore, the piezoelectric layer 20 is preferably polarized (poled) in the thickness direction.
図８に示すように、圧電フィルム１０は、このような圧電体層２０の一面に、第２電極層２６を有し、その上に第２保護層３０を有し、圧電体層２０の他方の面に、第１電極層２４を有し、その上に第１保護層２８を有してなる構成を有する。ここで、第１電極層２４と第２電極層２６とが電極対を形成する。
As shown in FIG. 8, the piezoelectric film 10 has a second electrode layer 26 on one side of the piezoelectric layer 20, a second protective layer 30 thereon, and a second electrode layer 26 on one side of the piezoelectric layer 20. It has a structure in which it has a first electrode layer 24 on its surface and a first protective layer 28 thereon. Here, the first electrode layer 24 and the second electrode layer 26 form an electrode pair.
すなわち、圧電フィルム１０は、圧電体層２０の両面を電極対、すなわち、第２電極層２６および第１電極層２４で挟持し、この積層体を、第２保護層３０および第１保護層２８で挟持してなる構成を有する。
このように、圧電フィルム１０において、第２電極層２６および第１電極層２４で挾持された領域は、印加された電圧に応じて伸縮される。
なお、第２電極層２６および第２保護層３０、ならびに、第１電極層２４および第１保護層２８は、圧電フィルム１０を説明するために、便宜的に付しているものである。従って、本発明における第１および第２には、技術的な意味は無く、また、実際の使用状態とは無関係である。 That is, in thepiezoelectric film 10, both surfaces of the piezoelectric layer 20 are sandwiched between an electrode pair, that is, a second electrode layer 26 and a first electrode layer 24, and this laminate is sandwiched between a second protective layer 30 and a first protective layer 28. It has a structure in which it is sandwiched between.
In this way, in thepiezoelectric film 10, the region sandwiched between the second electrode layer 26 and the first electrode layer 24 expands and contracts depending on the applied voltage.
Note that thesecond electrode layer 26 and the second protective layer 30, as well as the first electrode layer 24 and the first protective layer 28 are added for convenience in order to explain the piezoelectric film 10. Therefore, the first and second aspects of the present invention have no technical meaning and are unrelated to actual usage conditions.
このように、圧電フィルム１０において、第２電極層２６および第１電極層２４で挾持された領域は、印加された電圧に応じて伸縮される。
なお、第２電極層２６および第２保護層３０、ならびに、第１電極層２４および第１保護層２８は、圧電フィルム１０を説明するために、便宜的に付しているものである。従って、本発明における第１および第２には、技術的な意味は無く、また、実際の使用状態とは無関係である。 That is, in the
In this way, in the
Note that the
本発明において圧電フィルム１０は、これらの層に加えて、例えば、電極層と圧電体層２０とを貼着するための貼着層、および、電極層と保護層とを貼着するための貼着層を有してもよい。
貼着剤は、接着剤でも粘着剤でもよい。また、貼着剤は、圧電体層２０から圧電体粒子３６を除いた高分子材料すなわちマトリックス３４と同じ材料も、好適に利用可能である。なお、貼着層は、第１電極層２４側および第２電極層２６側の両方に有してもよく、第１電極層２４側および第２電極層２６側の一方のみに有してもよい。 In the present invention, thepiezoelectric film 10 includes, in addition to these layers, an adhesive layer for pasting the electrode layer and the piezoelectric layer 20, and a pasting layer for pasting the electrode layer and the protective layer. It may have an attached layer.
The adhesive may be an adhesive or a pressure-sensitive adhesive. Further, as the adhesive, a polymeric material obtained by removing thepiezoelectric particles 36 from the piezoelectric layer 20, that is, the same material as the matrix 34, can also be suitably used. Note that the adhesive layer may be provided on both the first electrode layer 24 side and the second electrode layer 26 side, or may be provided only on one of the first electrode layer 24 side and the second electrode layer 26 side. good.
貼着剤は、接着剤でも粘着剤でもよい。また、貼着剤は、圧電体層２０から圧電体粒子３６を除いた高分子材料すなわちマトリックス３４と同じ材料も、好適に利用可能である。なお、貼着層は、第１電極層２４側および第２電極層２６側の両方に有してもよく、第１電極層２４側および第２電極層２６側の一方のみに有してもよい。 In the present invention, the
The adhesive may be an adhesive or a pressure-sensitive adhesive. Further, as the adhesive, a polymeric material obtained by removing the
圧電フィルム１０において、第１保護層２８および第２保護層３０は、第１電極層２４および第２電極層２６を被覆すると共に、圧電体層２０に適度な剛性と機械的強度を付与する役目を担っている。すなわち、圧電フィルム１０において、マトリックス３４と圧電体粒子３６とからなる圧電体層２０は、ゆっくりとした曲げ変形に対しては、非常に優れた可撓性を示す一方で、用途によっては、剛性や機械的強度が不足する場合がある。圧電フィルム１０は、それを補うために第１保護層２８および第２保護層３０が設けられる。
第１保護層２８と第２保護層３０とは、配置位置が異なるのみで、構成は同じである。従って、以下の説明においては、第１保護層２８および第２保護層３０を区別する必要がない場合には、両部材をまとめて、保護層ともいう。 In thepiezoelectric film 10, the first protective layer 28 and the second protective layer 30 cover the first electrode layer 24 and the second electrode layer 26, and also serve to impart appropriate rigidity and mechanical strength to the piezoelectric layer 20. is in charge of That is, in the piezoelectric film 10, the piezoelectric layer 20 consisting of the matrix 34 and the piezoelectric particles 36 exhibits excellent flexibility against slow bending deformation, but depending on the application, it may have low rigidity. or mechanical strength may be insufficient. The piezoelectric film 10 is provided with a first protective layer 28 and a second protective layer 30 to compensate for this.
The firstprotective layer 28 and the second protective layer 30 have the same structure, except for the arrangement position. Therefore, in the following description, when there is no need to distinguish between the first protective layer 28 and the second protective layer 30, both members are collectively referred to as protective layers.
第１保護層２８と第２保護層３０とは、配置位置が異なるのみで、構成は同じである。従って、以下の説明においては、第１保護層２８および第２保護層３０を区別する必要がない場合には、両部材をまとめて、保護層ともいう。 In the
The first
保護層には、制限はなく、各種のシート状物が利用可能であり、一例として、各種の樹脂フィルムが好適に例示される。
中でも、優れた機械的特性および耐熱性を有するなどの理由により、ポリエチレンテレフタレート（ＰＥＴ）、ポリプロピレン（ＰＰ）、ポリスチレン（ＰＳ）、ポリカーボネート（ＰＣ）、ポリフェニレンサルファイト（ＰＰＳ）、ポリメチルメタクリレート（ＰＭＭＡ）、ポリエーテルイミド（ＰＥＩ）、ポリイミド（ＰＩ）、ポリエチレンナフタレート（ＰＥＮ）、トリアセチルセルロース（ＴＡＣ）、および、環状オレフィン系樹脂等からなる樹脂フィルムが、好適に利用される。 The protective layer is not limited and various sheet-like materials can be used, and various resin films are suitably exemplified as an example.
Among them, polyethylene terephthalate (PET), polypropylene (PP), polystyrene (PS), polycarbonate (PC), polyphenylene sulfite (PPS), and polymethyl methacrylate (PMMA) are used because of their excellent mechanical properties and heat resistance. ), polyetherimide (PEI), polyimide (PI), polyethylene naphthalate (PEN), triacetyl cellulose (TAC), cyclic olefin resin, and the like are suitably used.
中でも、優れた機械的特性および耐熱性を有するなどの理由により、ポリエチレンテレフタレート（ＰＥＴ）、ポリプロピレン（ＰＰ）、ポリスチレン（ＰＳ）、ポリカーボネート（ＰＣ）、ポリフェニレンサルファイト（ＰＰＳ）、ポリメチルメタクリレート（ＰＭＭＡ）、ポリエーテルイミド（ＰＥＩ）、ポリイミド（ＰＩ）、ポリエチレンナフタレート（ＰＥＮ）、トリアセチルセルロース（ＴＡＣ）、および、環状オレフィン系樹脂等からなる樹脂フィルムが、好適に利用される。 The protective layer is not limited and various sheet-like materials can be used, and various resin films are suitably exemplified as an example.
Among them, polyethylene terephthalate (PET), polypropylene (PP), polystyrene (PS), polycarbonate (PC), polyphenylene sulfite (PPS), and polymethyl methacrylate (PMMA) are used because of their excellent mechanical properties and heat resistance. ), polyetherimide (PEI), polyimide (PI), polyethylene naphthalate (PEN), triacetyl cellulose (TAC), cyclic olefin resin, and the like are suitably used.
保護層の厚さにも、制限はない。また、第１保護層２８および第２保護層３０の厚さは、基本的に同じであるが、異なってもよい。
ここで、保護層の剛性が高過ぎると、圧電体層２０の伸縮を拘束するばかりか、可撓性も損なわれる。そのため、機械的強度やシート状物としての良好なハンドリング性が要求される場合を除けば、保護層は、薄いほど有利である。 There is also no limit to the thickness of the protective layer. Moreover, the thicknesses of the firstprotective layer 28 and the second protective layer 30 are basically the same, but may be different.
Here, if the rigidity of the protective layer is too high, it not only restricts the expansion and contraction of thepiezoelectric layer 20 but also impairs its flexibility. Therefore, the thinner the protective layer is, the more advantageous it is, except when mechanical strength and good handling properties as a sheet-like product are required.
ここで、保護層の剛性が高過ぎると、圧電体層２０の伸縮を拘束するばかりか、可撓性も損なわれる。そのため、機械的強度やシート状物としての良好なハンドリング性が要求される場合を除けば、保護層は、薄いほど有利である。 There is also no limit to the thickness of the protective layer. Moreover, the thicknesses of the first
Here, if the rigidity of the protective layer is too high, it not only restricts the expansion and contraction of the
圧電フィルム１０においては、保護層の厚さが、圧電体層２０の厚さの２倍以下であれば、剛性の確保と適度な柔軟性との両立等の点で好ましい結果を得ることができる。
例えば、圧電体層２０の厚さが５０μｍで保護層がＰＥＴからなる場合、保護層の厚さは、１００μｍ以下が好ましく、５０μｍ以下がより好ましく、２５μｍ以下がさらに好ましい。 In thepiezoelectric film 10, if the thickness of the protective layer is at most twice the thickness of the piezoelectric layer 20, favorable results can be obtained in terms of ensuring both rigidity and appropriate flexibility. .
For example, when thepiezoelectric layer 20 has a thickness of 50 μm and the protective layer is made of PET, the thickness of the protective layer is preferably 100 μm or less, more preferably 50 μm or less, and even more preferably 25 μm or less.
例えば、圧電体層２０の厚さが５０μｍで保護層がＰＥＴからなる場合、保護層の厚さは、１００μｍ以下が好ましく、５０μｍ以下がより好ましく、２５μｍ以下がさらに好ましい。 In the
For example, when the
圧電フィルム１０において、圧電体層２０と第２保護層３０との間には第２電極層２６が、圧電体層２０と第１保護層２８との間には第１電極層２４が、それぞれ形成される。第１電極層２４および第２電極層２６は、圧電体層２０（圧電フィルム１０）に電圧を印加するために設けられる。
In the piezoelectric film 10, a second electrode layer 26 is provided between the piezoelectric layer 20 and the second protective layer 30, and a first electrode layer 24 is provided between the piezoelectric layer 20 and the first protective layer 28. It is formed. The first electrode layer 24 and the second electrode layer 26 are provided to apply a voltage to the piezoelectric layer 20 (piezoelectric film 10).
第１電極層２４および第２電極層２６は、位置が異なる以外は、基本的に同じものである。従って、以下の説明においては、第１電極層２４および第２電極層２６を区別する必要がない場合には、両部材をまとめて、電極層ともいう。
The first electrode layer 24 and the second electrode layer 26 are basically the same except for their positions. Therefore, in the following description, when there is no need to distinguish between the first electrode layer 24 and the second electrode layer 26, both members are collectively referred to as electrode layers.
本発明において、電極層の形成材料には制限はなく、各種の導電体が利用可能である。具体的には、炭素、パラジウム、鉄、錫、アルミニウム、ニッケル、白金、金、銀、銅、チタン、クロムおよびモリブデン等の金属、これらの合金、これらの金属および合金の積層体および複合体、ならびに、酸化インジウムスズ等が例示される。あるいは、ＰＥＤＯＴ／ＰＰＳ（ポリエチレンジオキシチオフェン－ポリスチレンスルホン酸）などの導電性高分子も例示される。中でも、銅、アルミニウム、金、銀、白金、および、酸化インジウムスズは、電極層として好適に例示される。その中でも、導電性、コストおよび可撓性等の観点から銅がより好ましい。
In the present invention, there are no restrictions on the material for forming the electrode layer, and various conductors can be used. Specifically, metals such as carbon, palladium, iron, tin, aluminum, nickel, platinum, gold, silver, copper, titanium, chromium, and molybdenum, alloys thereof, laminates and composites of these metals and alloys, Further, indium tin oxide and the like are exemplified. Alternatively, conductive polymers such as PEDOT/PPS (polyethylenedioxythiophene-polystyrene sulfonic acid) are also exemplified. Among them, copper, aluminum, gold, silver, platinum, and indium tin oxide are preferably exemplified as the electrode layer. Among these, copper is more preferable from the viewpoints of conductivity, cost, flexibility, and the like.
また、電極層の形成方法にも制限はなく、真空蒸着およびスパッタリング等の気相堆積法（真空成膜法）、めっきによる成膜、ならびに、上記材料で形成された箔を貼着する方法等、公知の方法が、各種、利用可能である。
Furthermore, there are no restrictions on the method of forming the electrode layer, including vapor deposition methods (vacuum film formation methods) such as vacuum evaporation and sputtering, film formation by plating, and methods of pasting foil made of the above materials. Various known methods are available.
中でも特に、圧電フィルム１０の可撓性が確保できる等の理由で、真空蒸着によって成膜された銅およびアルミニウム等の薄膜は、電極層として、好適に利用される。その中でも特に、真空蒸着による銅の薄膜は、好適に利用される。
Among these, thin films made of copper, aluminum, or the like formed by vacuum deposition are particularly preferably used as the electrode layer because the flexibility of the piezoelectric film 10 can be ensured. Among these, a copper thin film formed by vacuum evaporation is particularly preferably used.
電極層の厚さには、制限はない。また、第１電極層２４および第２電極層２６の厚さは、基本的に同じであるが、異なってもよい。
ここで、前述の保護層と同様に、電極層の剛性が高過ぎると、圧電体層２０の伸縮を拘束するばかりか、可撓性も損なわれる。そのため、電極層は、電気抵抗が高くなり過ぎない範囲であれば、薄いほど有利である。 There is no limit to the thickness of the electrode layer. Further, the thicknesses of thefirst electrode layer 24 and the second electrode layer 26 are basically the same, but may be different.
Here, similarly to the above-mentioned protective layer, if the rigidity of the electrode layer is too high, it not only restricts the expansion and contraction of thepiezoelectric layer 20 but also impairs its flexibility. Therefore, it is advantageous for the electrode layer to be thinner, as long as the electrical resistance does not become too high.
ここで、前述の保護層と同様に、電極層の剛性が高過ぎると、圧電体層２０の伸縮を拘束するばかりか、可撓性も損なわれる。そのため、電極層は、電気抵抗が高くなり過ぎない範囲であれば、薄いほど有利である。 There is no limit to the thickness of the electrode layer. Further, the thicknesses of the
Here, similarly to the above-mentioned protective layer, if the rigidity of the electrode layer is too high, it not only restricts the expansion and contraction of the
圧電フィルム１０においては、電極層の厚さと、ヤング率との積が、保護層の厚さとヤング率との積を下回れば、可撓性を大きく損なうことがないため、好適である。
例えば、保護層がＰＥＴ（ヤング率：約６．２ＧＰａ）で、電極層が銅（ヤング率：約１３０ＧＰａ）からなる組み合わせの場合、保護層の厚さが２５μｍだとすると、電極層の厚さは、１．２μｍ以下が好ましく、０．３μｍ以下がより好ましく、中でも０．１μｍ以下とするのが好ましい。 In thepiezoelectric film 10, it is preferable that the product of the thickness of the electrode layer and the Young's modulus be less than the product of the thickness of the protective layer and the Young's modulus, since flexibility will not be significantly impaired.
For example, in the case of a combination in which the protective layer is made of PET (Young's modulus: approximately 6.2 GPa) and the electrode layer is made of copper (Young's modulus: approximately 130 GPa), and the thickness of the protective layer is 25 μm, the thickness of the electrode layer is The thickness is preferably 1.2 μm or less, more preferably 0.3 μm or less, and particularly preferably 0.1 μm or less.
例えば、保護層がＰＥＴ（ヤング率：約６．２ＧＰａ）で、電極層が銅（ヤング率：約１３０ＧＰａ）からなる組み合わせの場合、保護層の厚さが２５μｍだとすると、電極層の厚さは、１．２μｍ以下が好ましく、０．３μｍ以下がより好ましく、中でも０．１μｍ以下とするのが好ましい。 In the
For example, in the case of a combination in which the protective layer is made of PET (Young's modulus: approximately 6.2 GPa) and the electrode layer is made of copper (Young's modulus: approximately 130 GPa), and the thickness of the protective layer is 25 μm, the thickness of the electrode layer is The thickness is preferably 1.2 μm or less, more preferably 0.3 μm or less, and particularly preferably 0.1 μm or less.
上述したように、圧電フィルム１０は、高分子材料を含むマトリックス３４に圧電体粒子３６を分散してなる圧電体層２０を、第１電極層２４および第２電極層２６で挟持し、さらに、この積層体を、第１保護層２８および第２保護層３０を挟持してなる構成を有する。
このような圧電フィルム１０は、動的粘弾性測定による周波数１Ｈｚでの損失正接（Ｔａｎδ）の極大値が常温に存在するのが好ましく、０．１以上となる極大値が常温に存在するのがより好ましい。
これにより、圧電フィルム１０が外部から数Ｈｚ以下の比較的ゆっくりとした、大きな曲げ変形を受けたとしても、歪みエネルギーを効果的に熱として外部へ拡散できるため、高分子マトリックスと圧電体粒子との界面で亀裂が発生するのを防ぐことができる。 As described above, thepiezoelectric film 10 has a piezoelectric layer 20 formed by dispersing piezoelectric particles 36 in a matrix 34 containing a polymeric material, sandwiched between the first electrode layer 24 and the second electrode layer 26, and further includes: This laminate has a structure in which a first protective layer 28 and a second protective layer 30 are sandwiched between them.
In such apiezoelectric film 10, it is preferable that the maximum value of the loss tangent (Tan δ) at a frequency of 1 Hz as measured by dynamic viscoelasticity exists at room temperature, and it is preferable that the maximum value of 0.1 or more exists at room temperature. More preferred.
As a result, even if thepiezoelectric film 10 is subjected to a relatively slow and large bending deformation of several Hz or less from the outside, the strain energy can be effectively diffused to the outside as heat, so that the polymer matrix and piezoelectric particles are This can prevent cracks from forming at the interface.
このような圧電フィルム１０は、動的粘弾性測定による周波数１Ｈｚでの損失正接（Ｔａｎδ）の極大値が常温に存在するのが好ましく、０．１以上となる極大値が常温に存在するのがより好ましい。
これにより、圧電フィルム１０が外部から数Ｈｚ以下の比較的ゆっくりとした、大きな曲げ変形を受けたとしても、歪みエネルギーを効果的に熱として外部へ拡散できるため、高分子マトリックスと圧電体粒子との界面で亀裂が発生するのを防ぐことができる。 As described above, the
In such a
As a result, even if the
圧電フィルム１０は、動的粘弾性測定による周波数１Ｈｚでの貯蔵弾性率（Ｅ’）が、０℃において１０～３０ＧＰａ、５０℃において１～１０ＧＰａであるのが好ましい。なお、この条件に関しては、圧電体層２０も同様である。
これにより、常温で圧電フィルム１０が貯蔵弾性率（Ｅ’）に大きな周波数分散を有することができる。すなわち、２０Ｈｚ～２０ｋＨｚの振動に対しては硬く、数Ｈｚ以下の振動に対しては柔らかく振る舞うことができる。 Thepiezoelectric film 10 preferably has a storage modulus (E') at a frequency of 1 Hz measured by dynamic viscoelasticity measurement of 10 to 30 GPa at 0°C and 1 to 10 GPa at 50°C. Note that this condition also applies to the piezoelectric layer 20.
This allows thepiezoelectric film 10 to have a large frequency dispersion in storage modulus (E') at room temperature. That is, it is hard against vibrations of 20 Hz to 20 kHz, and can behave soft against vibrations of several Hz or less.
これにより、常温で圧電フィルム１０が貯蔵弾性率（Ｅ’）に大きな周波数分散を有することができる。すなわち、２０Ｈｚ～２０ｋＨｚの振動に対しては硬く、数Ｈｚ以下の振動に対しては柔らかく振る舞うことができる。 The
This allows the
また、圧電フィルム１０は、厚さと動的粘弾性測定による周波数１Ｈｚでの貯蔵弾性率（Ｅ’）との積が、０℃において１．０×１０5～２．０×１０6Ｎ／ｍ、５０℃において１．０×１０5～１．０×１０6Ｎ／ｍであるのが好ましい。なお、この条件に関しては、圧電体層２０も同様である。
これにより、圧電フィルム１０が可撓性および音響特性を損なわない範囲で、適度な剛性と機械的強度を備えることができる。 Furthermore, thepiezoelectric film 10 has a product of thickness and storage modulus (E') at a frequency of 1 Hz measured by dynamic viscoelasticity measurement of 1.0×10 5 to 2.0×10 6 N/m at 0°C. , 1.0×10 5 to 1.0×10 6 N/m at 50°C. Note that this condition also applies to the piezoelectric layer 20.
Thereby, thepiezoelectric film 10 can have appropriate rigidity and mechanical strength without impairing its flexibility and acoustic properties.
これにより、圧電フィルム１０が可撓性および音響特性を損なわない範囲で、適度な剛性と機械的強度を備えることができる。 Furthermore, the
Thereby, the
さらに、圧電フィルム１０は、動的粘弾性測定から得られたマスターカーブにおいて、２５℃、周波数１ｋＨｚにおける損失正接（Ｔａｎδ）が、０．０５以上であるのが好ましい。この条件に関しては、圧電体層２０も同様である。
これにより、圧電フィルム１０を用いたスピーカの周波数特性が平滑になり、スピーカの曲率の変化に伴い最低共振周波数ｆ０が変化した際の音質の変化量も小さくできる。 Furthermore, thepiezoelectric film 10 preferably has a loss tangent (Tan δ) of 0.05 or more at 25° C. and a frequency of 1 kHz in a master curve obtained from dynamic viscoelasticity measurement. Regarding this condition, the piezoelectric layer 20 is also the same.
As a result, the frequency characteristics of the speaker using thepiezoelectric film 10 are smoothed, and the amount of change in sound quality when the lowest resonance frequency f 0 changes due to a change in the curvature of the speaker can also be reduced.
これにより、圧電フィルム１０を用いたスピーカの周波数特性が平滑になり、スピーカの曲率の変化に伴い最低共振周波数ｆ０が変化した際の音質の変化量も小さくできる。 Furthermore, the
As a result, the frequency characteristics of the speaker using the
なお、本発明において、圧電フィルム１０および圧電体層２０等の貯蔵弾性率（ヤング率）および損失正接は、公知の方法で測定すればよい。一例として、エスアイアイ・ナノテクノロジー社製（ＳＩＩナノテクノロジー社製）の動的粘弾性測定装置ＤＭＳ６１００を用いて測定すればよい。
測定条件としては、一例として、測定周波数は０．１Ｈｚ～２０Ｈｚ（０．１Ｈｚ、０．２Ｈｚ、０．５Ｈｚ、１Ｈｚ、２Ｈｚ、５Ｈｚ、１０Ｈｚおよび２０Ｈｚ）が、測定温度は－５０～１５０℃が、昇温速度は２℃／分（窒素雰囲気中）が、サンプルサイズは４０ｍｍ×１０ｍｍ（クランプ領域込み）が、チャック間距離は２０ｍｍが、それぞれ、例示される。 In the present invention, the storage modulus (Young's modulus) and loss tangent of thepiezoelectric film 10, piezoelectric layer 20, etc. may be measured by a known method. As an example, the measurement may be performed using a dynamic viscoelasticity measuring device DMS6100 manufactured by SII Nanotechnology.
As an example of the measurement conditions, the measurement frequency is 0.1Hz to 20Hz (0.1Hz, 0.2Hz, 0.5Hz, 1Hz, 2Hz, 5Hz, 10Hz and 20Hz), and the measurement temperature is -50 to 150℃. Examples include a temperature increase rate of 2° C./min (in a nitrogen atmosphere), a sample size of 40 mm×10 mm (including the clamp area), and a distance between chucks of 20 mm.
測定条件としては、一例として、測定周波数は０．１Ｈｚ～２０Ｈｚ（０．１Ｈｚ、０．２Ｈｚ、０．５Ｈｚ、１Ｈｚ、２Ｈｚ、５Ｈｚ、１０Ｈｚおよび２０Ｈｚ）が、測定温度は－５０～１５０℃が、昇温速度は２℃／分（窒素雰囲気中）が、サンプルサイズは４０ｍｍ×１０ｍｍ（クランプ領域込み）が、チャック間距離は２０ｍｍが、それぞれ、例示される。 In the present invention, the storage modulus (Young's modulus) and loss tangent of the
As an example of the measurement conditions, the measurement frequency is 0.1Hz to 20Hz (0.1Hz, 0.2Hz, 0.5Hz, 1Hz, 2Hz, 5Hz, 10Hz and 20Hz), and the measurement temperature is -50 to 150℃. Examples include a temperature increase rate of 2° C./min (in a nitrogen atmosphere), a sample size of 40 mm×10 mm (including the clamp area), and a distance between chucks of 20 mm.
圧電素子５０において、圧電フィルム１０の第１電極層２４および第２電極層２６には、圧電フィルム１０を伸縮させる駆動電圧を印加すなわち駆動電力を供給する、電源（外部電源）が接続される。
電源には、制限はなく、直流電源でも交流電源でもよい。また、駆動電圧も、圧電フィルム１０の圧電体層２０の厚さおよび形成材料等に応じて、圧電フィルム１０を適正に駆動できる駆動電圧を、適宜、設定すればよい。 In thepiezoelectric element 50, a power source (external power source) is connected to the first electrode layer 24 and the second electrode layer 26 of the piezoelectric film 10, which applies a driving voltage to expand and contract the piezoelectric film 10, that is, supplies driving power.
The power source is not limited and may be either a direct current power source or an alternating current power source. Furthermore, the drive voltage may be appropriately set to a drive voltage that can appropriately drive thepiezoelectric film 10, depending on the thickness and forming material of the piezoelectric layer 20 of the piezoelectric film 10.
電源には、制限はなく、直流電源でも交流電源でもよい。また、駆動電圧も、圧電フィルム１０の圧電体層２０の厚さおよび形成材料等に応じて、圧電フィルム１０を適正に駆動できる駆動電圧を、適宜、設定すればよい。 In the
The power source is not limited and may be either a direct current power source or an alternating current power source. Furthermore, the drive voltage may be appropriately set to a drive voltage that can appropriately drive the
前述のとおり、圧電フィルムを折り返して積層した圧電素子の場合には、第１電極層２４および第２電極層２６から電極の引き出しは、突出部１１ｂにおいて行われる。第１電極層２４および第２電極層２６から電極の引き出し方法には、制限はなく、公知の各種の方法が利用可能である。
一例として、第１電極層２４および第２電極層２６に銅箔等の導電体を接続して外部に電極を引き出す方法、および、レーザ等によって第１保護層２８および第２保護層３０に貫通孔を形成して、この貫通孔に導電性材料を充填して外部に電極を引き出す方法、等が例示される。
好適な電極の引き出し方法として、特開２０１４－２０９７２４号公報に記載される方法、および、特開２０１６－０１５３５４号公報に記載される方法等が例示される。 As described above, in the case of a piezoelectric element in which piezoelectric films are folded and laminated, electrodes are drawn out from thefirst electrode layer 24 and the second electrode layer 26 at the protrusion 11b. There is no limit to the method of drawing out the electrodes from the first electrode layer 24 and the second electrode layer 26, and various known methods can be used.
As an example, a method of connecting a conductive material such as copper foil to thefirst electrode layer 24 and the second electrode layer 26 and drawing out the electrodes to the outside, and a method of penetrating the first protective layer 28 and the second protective layer 30 with a laser or the like are available. Examples include a method of forming a hole, filling the through hole with a conductive material, and drawing out an electrode to the outside.
Examples of suitable electrode extraction methods include the method described in JP-A No. 2014-209724 and the method described in JP-A No. 2016-015354.
一例として、第１電極層２４および第２電極層２６に銅箔等の導電体を接続して外部に電極を引き出す方法、および、レーザ等によって第１保護層２８および第２保護層３０に貫通孔を形成して、この貫通孔に導電性材料を充填して外部に電極を引き出す方法、等が例示される。
好適な電極の引き出し方法として、特開２０１４－２０９７２４号公報に記載される方法、および、特開２０１６－０１５３５４号公報に記載される方法等が例示される。 As described above, in the case of a piezoelectric element in which piezoelectric films are folded and laminated, electrodes are drawn out from the
As an example, a method of connecting a conductive material such as copper foil to the
Examples of suitable electrode extraction methods include the method described in JP-A No. 2014-209724 and the method described in JP-A No. 2016-015354.
［圧電フィルムの製造方法］
本発明の圧電フィルムの製造方法は、
高分子材料を含むマトリックス中に圧電体粒子を含む高分子複合圧電体からなる圧電体層と、圧電体層の両面に設けられる電極層と、を有する圧電フィルムの製造方法であって、
一方の電極層の主面に、未分極の圧電体層を形成する圧電体層形成工程と、
圧電体層形成工程の後に、圧電体層の一部を分極処理する分極処理工程と、
分極処理工程の後に、圧電体層の主面に他方の電極層を積層する電極積層工程と、を有し、
分極処理工程は、圧電体層の一方の電極層とは反対側の主面に対面して電極部材を配置して、一方の電極層をアースに接続した後、電極部材との間に直流電圧を印加して分極処理を行うものであり、
分極処理される領域を規制することにより、圧電体層に分極された分極領域と、分極されていない未分極領域とを形成する、圧電フィルムの製造方法である。
また、好ましい態様として、本発明の圧電フィルムの製造方法は、分極処理がコロナポーリング処理であり、電極部材がワイヤー状のコロナ電極である。 [Method for manufacturing piezoelectric film]
The method for manufacturing a piezoelectric film of the present invention includes:
A method for producing a piezoelectric film having a piezoelectric layer made of a polymer composite piezoelectric material containing piezoelectric particles in a matrix containing a polymeric material, and electrode layers provided on both sides of the piezoelectric layer, the method comprising:
a piezoelectric layer forming step of forming an unpolarized piezoelectric layer on the main surface of one electrode layer;
After the piezoelectric layer forming step, a polarization treatment step of polarizing a part of the piezoelectric layer;
After the polarization treatment step, an electrode lamination step of laminating the other electrode layer on the main surface of the piezoelectric layer,
In the polarization process, an electrode member is placed facing the main surface of the piezoelectric layer on the opposite side from one electrode layer, and after one electrode layer is connected to the ground, a DC voltage is applied between the electrode member and the electrode member. The polarization process is performed by applying
This is a method of manufacturing a piezoelectric film in which a polarized region and an unpolarized region are formed in a piezoelectric layer by regulating the region to be polarized.
Moreover, as a preferable embodiment, in the piezoelectric film manufacturing method of the present invention, the polarization treatment is a corona poling treatment, and the electrode member is a wire-shaped corona electrode.
本発明の圧電フィルムの製造方法は、
高分子材料を含むマトリックス中に圧電体粒子を含む高分子複合圧電体からなる圧電体層と、圧電体層の両面に設けられる電極層と、を有する圧電フィルムの製造方法であって、
一方の電極層の主面に、未分極の圧電体層を形成する圧電体層形成工程と、
圧電体層形成工程の後に、圧電体層の一部を分極処理する分極処理工程と、
分極処理工程の後に、圧電体層の主面に他方の電極層を積層する電極積層工程と、を有し、
分極処理工程は、圧電体層の一方の電極層とは反対側の主面に対面して電極部材を配置して、一方の電極層をアースに接続した後、電極部材との間に直流電圧を印加して分極処理を行うものであり、
分極処理される領域を規制することにより、圧電体層に分極された分極領域と、分極されていない未分極領域とを形成する、圧電フィルムの製造方法である。
また、好ましい態様として、本発明の圧電フィルムの製造方法は、分極処理がコロナポーリング処理であり、電極部材がワイヤー状のコロナ電極である。 [Method for manufacturing piezoelectric film]
The method for manufacturing a piezoelectric film of the present invention includes:
A method for producing a piezoelectric film having a piezoelectric layer made of a polymer composite piezoelectric material containing piezoelectric particles in a matrix containing a polymeric material, and electrode layers provided on both sides of the piezoelectric layer, the method comprising:
a piezoelectric layer forming step of forming an unpolarized piezoelectric layer on the main surface of one electrode layer;
After the piezoelectric layer forming step, a polarization treatment step of polarizing a part of the piezoelectric layer;
After the polarization treatment step, an electrode lamination step of laminating the other electrode layer on the main surface of the piezoelectric layer,
In the polarization process, an electrode member is placed facing the main surface of the piezoelectric layer on the opposite side from one electrode layer, and after one electrode layer is connected to the ground, a DC voltage is applied between the electrode member and the electrode member. The polarization process is performed by applying
This is a method of manufacturing a piezoelectric film in which a polarized region and an unpolarized region are formed in a piezoelectric layer by regulating the region to be polarized.
Moreover, as a preferable embodiment, in the piezoelectric film manufacturing method of the present invention, the polarization treatment is a corona poling treatment, and the electrode member is a wire-shaped corona electrode.
以下、図９～図１３を参照して、圧電フィルム１０の製造方法の一例を説明する。
An example of a method for manufacturing the piezoelectric film 10 will be described below with reference to FIGS. 9 to 13.
まず、図９に示す、第１保護層２８の表面に第１電極層２４が形成されたシート状物１２ａを準備する。さらに、図１３に概念的に示す、第２保護層３０の表面に第２電極層２６が形成されたシート状物１２ｃを準備する。
First, a sheet-like material 12a shown in FIG. 9 in which the first electrode layer 24 is formed on the surface of the first protective layer 28 is prepared. Furthermore, a sheet-like material 12c, conceptually shown in FIG. 13, in which a second electrode layer 26 is formed on the surface of a second protective layer 30 is prepared.
シート状物１２ａは、第１保護層２８の表面に、真空蒸着、スパッタリング、めっき等によって第１電極層２４として銅薄膜等を形成して、作製すればよい。同様に、シート状物１２ｃは、第２保護層３０の表面に、真空蒸着、スパッタリング、めっき等によって第２電極層２６として銅薄膜等を形成して、作製すればよい。
あるいは、保護層の上に銅薄膜等が形成された市販品をシート状物を、シート状物１２ａおよび／またはシート状物１２ｃとして利用してもよい。
シート状物１２ａおよびシート状物１２ｃは、同じものでもよく、異なるものでもよい。 The sheet-like material 12a may be produced by forming a copper thin film or the like as the first electrode layer 24 on the surface of the first protective layer 28 by vacuum evaporation, sputtering, plating, or the like. Similarly, the sheet-like material 12c may be produced by forming a copper thin film or the like as the second electrode layer 26 on the surface of the second protective layer 30 by vacuum evaporation, sputtering, plating, or the like.
Alternatively, a commercially available sheet material in which a copper thin film or the like is formed on a protective layer may be used as thesheet material 12a and/or the sheet material 12c.
The sheet-like material 12a and the sheet-like material 12c may be the same or different.
あるいは、保護層の上に銅薄膜等が形成された市販品をシート状物を、シート状物１２ａおよび／またはシート状物１２ｃとして利用してもよい。
シート状物１２ａおよびシート状物１２ｃは、同じものでもよく、異なるものでもよい。 The sheet-
Alternatively, a commercially available sheet material in which a copper thin film or the like is formed on a protective layer may be used as the
The sheet-
なお、保護層が非常に薄く、ハンドリング性が悪い時などは、必要に応じて、セパレータ（仮支持体）付きの保護層を用いても良い。なお、セパレータとしては、厚さ２５～１００μｍのＰＥＴ等を用いることができる。セパレータは、電極層および保護層の熱圧着後、取り除けばよい。
Note that if the protective layer is very thin and has poor handling properties, a protective layer with a separator (temporary support) may be used as necessary. Note that as the separator, PET or the like having a thickness of 25 to 100 μm can be used. The separator may be removed after thermocompression bonding of the electrode layer and the protective layer.
次いで、図１０に示すように、シート状物１２ａの第１電極層２４上に、圧電体層２０となる塗料（塗布組成物）を塗布した後、硬化して圧電体層２０を形成する（圧電体層形成工程）。これにより、シート状物１２ａと圧電体層２０とを積層した圧電積層体１２ｂを作製する。圧電体層形成工程で形成した圧電体層２０は未分極の状態である。
Next, as shown in FIG. 10, a paint (coating composition) that will become the piezoelectric layer 20 is applied onto the first electrode layer 24 of the sheet-like material 12a, and then cured to form the piezoelectric layer 20 ( piezoelectric layer formation process). In this way, a piezoelectric laminate 12b in which the sheet-like material 12a and the piezoelectric layer 20 are laminated is manufactured. The piezoelectric layer 20 formed in the piezoelectric layer forming step is in an unpolarized state.
圧電体層２０の形成は、圧電体層２０を形成する材料に応じて、各種の方法が利用可能である。
一例として、まず、有機溶媒に、上述したシアノエチル化ＰＶＡ等の高分子材料を溶解し、さらに、ＰＺＴ粒子等の圧電体粒子３６を添加し、攪拌して塗料を調製する。
有機溶媒には制限はなく、ジメチルホルムアミド（ＤＭＦ）、メチルエチルケトン（ＭＥＫ）、および、シクロヘキサノン等の各種の有機溶媒が利用可能である。
シート状物１２ａを準備し、かつ、塗料を調製したら、この塗料をシート状物１２ａにキャスティング（塗布）して、有機溶媒を蒸発して乾燥する。これにより、図１０に示すように、第１保護層２８の上に第１電極層２４を有し、第１電極層２４の上に圧電体層２０を積層してなる圧電積層体１２ｂを作製する。 Various methods can be used to form thepiezoelectric layer 20 depending on the material used to form the piezoelectric layer 20.
As an example, first, a polymer material such as the above-mentioned cyanoethylated PVA is dissolved in an organic solvent, and thenpiezoelectric particles 36 such as PZT particles are added and stirred to prepare a paint.
There are no restrictions on the organic solvent, and various organic solvents such as dimethylformamide (DMF), methyl ethyl ketone (MEK), and cyclohexanone can be used.
After preparing the sheet-like material 12a and preparing the paint, the paint is cast (coated) on the sheet-like material 12a, and the organic solvent is evaporated and dried. Thereby, as shown in FIG. 10, a piezoelectric laminate 12b having the first electrode layer 24 on the first protective layer 28 and the piezoelectric layer 20 laminated on the first electrode layer 24 was manufactured. do.
一例として、まず、有機溶媒に、上述したシアノエチル化ＰＶＡ等の高分子材料を溶解し、さらに、ＰＺＴ粒子等の圧電体粒子３６を添加し、攪拌して塗料を調製する。
有機溶媒には制限はなく、ジメチルホルムアミド（ＤＭＦ）、メチルエチルケトン（ＭＥＫ）、および、シクロヘキサノン等の各種の有機溶媒が利用可能である。
シート状物１２ａを準備し、かつ、塗料を調製したら、この塗料をシート状物１２ａにキャスティング（塗布）して、有機溶媒を蒸発して乾燥する。これにより、図１０に示すように、第１保護層２８の上に第１電極層２４を有し、第１電極層２４の上に圧電体層２０を積層してなる圧電積層体１２ｂを作製する。 Various methods can be used to form the
As an example, first, a polymer material such as the above-mentioned cyanoethylated PVA is dissolved in an organic solvent, and then
There are no restrictions on the organic solvent, and various organic solvents such as dimethylformamide (DMF), methyl ethyl ketone (MEK), and cyclohexanone can be used.
After preparing the sheet-
塗料のキャスティング方法には制限はなく、バーコーター、スライドコーターおよびドクターナイフ等の公知の方法（塗布装置）が、全て、利用可能である。
あるいは高分子材料が加熱溶融可能な物であれば、高分子材料を加熱溶融して、これに圧電体粒子３６を添加してなる溶融物を作製し、押し出し成形等によって、図９に示すシート状物１２ａの上にシート状に押し出し、冷却することにより、図１０に示すような、圧電積層体１２ｂを作製してもよい。 There are no restrictions on the coating method, and all known methods (coating devices) such as a bar coater, slide coater, and doctor knife can be used.
Alternatively, if the polymeric material can be heated and melted, the polymeric material is heated and melted, thepiezoelectric particles 36 are added thereto to produce a melted material, and the sheet shown in FIG. 9 is formed by extrusion molding or the like. A piezoelectric laminate 12b as shown in FIG. 10 may be produced by extruding it in a sheet form onto the shaped object 12a and cooling it.
あるいは高分子材料が加熱溶融可能な物であれば、高分子材料を加熱溶融して、これに圧電体粒子３６を添加してなる溶融物を作製し、押し出し成形等によって、図９に示すシート状物１２ａの上にシート状に押し出し、冷却することにより、図１０に示すような、圧電積層体１２ｂを作製してもよい。 There are no restrictions on the coating method, and all known methods (coating devices) such as a bar coater, slide coater, and doctor knife can be used.
Alternatively, if the polymeric material can be heated and melted, the polymeric material is heated and melted, the
なお、上述のように、圧電体層２０において、マトリックス３４には、常温で粘弾性を有する高分子材料以外にも、ＰＶＤＦ等の高分子圧電材料を添加しても良い。
マトリックス３４に、これらの高分子圧電材料を添加する際には、上記塗料に添加する高分子圧電材料を溶解すればよい。あるいは、加熱溶融した常温で粘弾性を有する高分子材料に、添加する高分子圧電材料を添加して加熱溶融すればよい。 Note that, as described above, in thepiezoelectric layer 20, the matrix 34 may contain a polymeric piezoelectric material such as PVDF in addition to the polymeric material having viscoelasticity at room temperature.
When adding these polymer piezoelectric materials to thematrix 34, the polymer piezoelectric materials to be added to the paint may be dissolved. Alternatively, the polymeric piezoelectric material to be added may be added to a polymeric material that is heated and melted and has viscoelasticity at room temperature, and then heated and melted.
マトリックス３４に、これらの高分子圧電材料を添加する際には、上記塗料に添加する高分子圧電材料を溶解すればよい。あるいは、加熱溶融した常温で粘弾性を有する高分子材料に、添加する高分子圧電材料を添加して加熱溶融すればよい。 Note that, as described above, in the
When adding these polymer piezoelectric materials to the
圧電体層２０を形成したら、必要に応じて、カレンダ処理を行ってもよい。カレンダ処理は、１回でもよく、複数回、行ってもよい。
周知のように、カレンダ処理とは、加熱プレスや加熱ローラ等によって、被処理面を加熱しつつ押圧して、平坦化等を施す処理である。 Once thepiezoelectric layer 20 is formed, calendaring may be performed if necessary. Calendar processing may be performed once or multiple times.
As is well known, calendering is a process in which a surface to be treated is heated and pressed using a heated press, a heated roller, etc. to flatten the surface.
周知のように、カレンダ処理とは、加熱プレスや加熱ローラ等によって、被処理面を加熱しつつ押圧して、平坦化等を施す処理である。 Once the
As is well known, calendering is a process in which a surface to be treated is heated and pressed using a heated press, a heated roller, etc. to flatten the surface.
次いで、圧電積層体１２ｂの圧電体層２０に、分極処理（ポーリング）を行う（分極処理工程）。圧電体層２０の分極処理は、カレンダ処理の前に行ってもよいが、カレンダ処理を行った後に行うのが好ましい。
圧電体層２０の分極処理の方法には制限はなく、公知の方法が利用可能である。例えば、分極処理を行う対象に、直接、直流電界を印加する電界ポーリング、コロナポーリング処理等が例示される。
また、本発明の圧電フィルム１０においては、分極処理は、圧電体層２０の面方向ではなく、厚さ方向に分極を行う。 Next, polarization treatment (poling) is performed on thepiezoelectric layer 20 of the piezoelectric laminate 12b (polarization treatment step). Although the polarization treatment of the piezoelectric layer 20 may be performed before the calender treatment, it is preferably performed after the calender treatment.
There are no restrictions on the method for polarizing thepiezoelectric layer 20, and any known method can be used. Examples include electric field poling, corona poling, and the like, in which a DC electric field is directly applied to the object to be polarized.
Furthermore, in thepiezoelectric film 10 of the present invention, the polarization treatment is performed not in the plane direction of the piezoelectric layer 20 but in the thickness direction.
圧電体層２０の分極処理の方法には制限はなく、公知の方法が利用可能である。例えば、分極処理を行う対象に、直接、直流電界を印加する電界ポーリング、コロナポーリング処理等が例示される。
また、本発明の圧電フィルム１０においては、分極処理は、圧電体層２０の面方向ではなく、厚さ方向に分極を行う。 Next, polarization treatment (poling) is performed on the
There are no restrictions on the method for polarizing the
Furthermore, in the
ここで、本発明の製造方法においては、分極処理工程は、圧電体層２０の一方の電極層（第１電極層２４）とは反対側の主面に対面してコロナ電極を配置して、一方の電極層（第１電極層）をアースに接続した後、一方の電極層（第１電極層）とコロナ電極との間に電圧を印加してコロナ放電を生じさせることで分極処理を行うコロナポーリング処理であり、分極処理される領域を規制することにより、圧電体層２０に分極された分極領域と、分極されていない未分極領域とを形成するものである。
これにより、圧電体層が一部に分極されていない未分極領域を有する、圧電フィルムを作製することができる。 Here, in the manufacturing method of the present invention, the polarization treatment step includes arranging a corona electrode facing the main surface of thepiezoelectric layer 20 on the opposite side to one electrode layer (first electrode layer 24), After connecting one electrode layer (first electrode layer) to ground, polarization treatment is performed by applying a voltage between one electrode layer (first electrode layer) and the corona electrode to generate corona discharge. This is a corona poling process, and by regulating the area to be polarized, a polarized area and an unpolarized area are formed in the piezoelectric layer 20.
As a result, it is possible to produce a piezoelectric film in which the piezoelectric layer has an unpolarized region in which the piezoelectric layer is not polarized.
これにより、圧電体層が一部に分極されていない未分極領域を有する、圧電フィルムを作製することができる。 Here, in the manufacturing method of the present invention, the polarization treatment step includes arranging a corona electrode facing the main surface of the
As a result, it is possible to produce a piezoelectric film in which the piezoelectric layer has an unpolarized region in which the piezoelectric layer is not polarized.
分極処理される領域を規制する方法としては、例えば、ワイヤー状のコロナ電極の、コロナ放電が生じる領域の長さを圧電体層の幅よりも短くすることで、分極処理される領域を規制する方法、および、圧電体層の一方の電極層（第１電極層）とは反対側の主面上の一部に絶縁体またはアースに接続された導電体を配置することで、分極処理される領域を規制する方法等が挙げられる。
As a method of regulating the region to be polarized, for example, the length of the region where corona discharge occurs of a wire-shaped corona electrode is made shorter than the width of the piezoelectric layer, thereby regulating the region to be polarized. Polarization is performed by arranging an insulator or a conductor connected to ground on a part of the main surface of the piezoelectric layer opposite to one electrode layer (first electrode layer). Examples include methods of regulating areas.
図１１は、コロナ電極の、コロナ放電が生じる領域の長さを圧電体層の幅よりも短くすることで、分極処理される領域を規制する方法を説明するための図である。
図１１に示すように、圧電積層体１２ｂの圧電体層２０の第１電極層２４とは反対側の表面（上面）に対面して、この表面に沿って移動可能なワイヤー状のコロナ電極６０を配置する。圧電体層２０とコロナ電極６０との間隔は例えば１ｍｍ程度である。このコロナ電極６０と第１電極層２４とを直流電源に接続し、直流電源から第１電極層２４とコロナ電極６０との間に、数ｋＶ、例えば、６ｋＶの直流電圧を印加してコロナ放電を生じさせる。さらに、間隔を維持した状態で、圧電体層２０の上面に沿って、コロナ電極６０を移動（走査）して、圧電体層２０の分極処理を行う。これにより、圧電体層２０は厚さ方向に分極される。 FIG. 11 is a diagram for explaining a method of regulating the region to be polarized by making the length of the region of the corona electrode where corona discharge occurs shorter than the width of the piezoelectric layer.
As shown in FIG. 11, a wire-shapedcorona electrode 60 faces the surface (top surface) of the piezoelectric layer 20 of the piezoelectric laminate 12b opposite to the first electrode layer 24 and is movable along this surface. Place. The distance between the piezoelectric layer 20 and the corona electrode 60 is, for example, about 1 mm. This corona electrode 60 and the first electrode layer 24 are connected to a DC power source, and a DC voltage of several kV, for example, 6 kV is applied between the first electrode layer 24 and the corona electrode 60 from the DC power source to discharge the corona. cause Further, the corona electrode 60 is moved (scanned) along the upper surface of the piezoelectric layer 20 while maintaining the interval to polarize the piezoelectric layer 20. Thereby, the piezoelectric layer 20 is polarized in the thickness direction.
図１１に示すように、圧電積層体１２ｂの圧電体層２０の第１電極層２４とは反対側の表面（上面）に対面して、この表面に沿って移動可能なワイヤー状のコロナ電極６０を配置する。圧電体層２０とコロナ電極６０との間隔は例えば１ｍｍ程度である。このコロナ電極６０と第１電極層２４とを直流電源に接続し、直流電源から第１電極層２４とコロナ電極６０との間に、数ｋＶ、例えば、６ｋＶの直流電圧を印加してコロナ放電を生じさせる。さらに、間隔を維持した状態で、圧電体層２０の上面に沿って、コロナ電極６０を移動（走査）して、圧電体層２０の分極処理を行う。これにより、圧電体層２０は厚さ方向に分極される。 FIG. 11 is a diagram for explaining a method of regulating the region to be polarized by making the length of the region of the corona electrode where corona discharge occurs shorter than the width of the piezoelectric layer.
As shown in FIG. 11, a wire-shaped
その際、図１１に示すように、ワイヤー状のコロナ電極６０の一部を、アルミナ等の絶縁体である第１被覆部材６２で覆うことにより、第１被覆部材６２で覆った領域に対面する圧電体層２０の領域にはコロナ放電を生じさせず、分極処理されることを防止する。すなわち、図１１に示す例は、ワイヤー状のコロナ電極６０の一部を第１被覆部材６２で覆うことにより、コロナ電極６０の、コロナ放電が生じる領域の長さを圧電体層２０の幅よりも短くしている。これにより、圧電体層２０に未分極領域２０ｂと分極領域２０ａとを形成することができる。
At that time, as shown in FIG. 11, a part of the wire-shaped corona electrode 60 is covered with a first covering member 62 made of an insulator such as alumina, so that the wire-shaped corona electrode 60 faces the area covered with the first covering member 62. Corona discharge is not generated in the region of the piezoelectric layer 20, and polarization treatment is prevented. That is, in the example shown in FIG. 11, by covering a part of the wire-shaped corona electrode 60 with the first covering member 62, the length of the region of the corona electrode 60 where corona discharge occurs is made smaller than the width of the piezoelectric layer 20. It's also shorter. Thereby, unpolarized regions 20b and polarized regions 20a can be formed in the piezoelectric layer 20.
第１被覆部材６２の位置、長さ等は、圧電体層２０において未分極領域２０ｂを形成する領域に合わせて適宜設定すればよい。
また、第１被覆部材６２の材料としては、アルミナ、ジルコニア等を用いることができる。 The position, length, etc. of thefirst covering member 62 may be appropriately set according to the region of the piezoelectric layer 20 in which the unpolarized region 20b is formed.
Further, as the material of thefirst covering member 62, alumina, zirconia, etc. can be used.
また、第１被覆部材６２の材料としては、アルミナ、ジルコニア等を用いることができる。 The position, length, etc. of the
Further, as the material of the
なお、図１１に示す例では、コロナ電極６０の一部を、第１被覆部材６２で覆うことにより、圧電体層２０に未分極領域２０ｂを形成する構成としたがこれに限定はされない。
例えば、コロナ電極６０自体の長さを、圧電体層２０の幅（ワイヤー状のコロナ電極の長手方向の幅）よりも短くして、圧電体層２０の、コロナ電極６０と対面しない領域にコロナ放電を生じさせずに未分極領域２０ｂを形成するようにしてもよい。あるいは、コロナ電極６０の一部をタングステンワイヤーにしてコロナ放電を生じにくくして未分極領域２０ｂを形成するようにしてもよい。 In the example shown in FIG. 11, a part of thecorona electrode 60 is covered with the first covering member 62 to form the unpolarized region 20b in the piezoelectric layer 20, but the present invention is not limited to this.
For example, the length of thecorona electrode 60 itself may be made shorter than the width of the piezoelectric layer 20 (width in the longitudinal direction of the wire-shaped corona electrode), and the corona electrode may be placed in a region of the piezoelectric layer 20 that does not face the corona electrode 60. The unpolarized region 20b may be formed without causing discharge. Alternatively, a portion of the corona electrode 60 may be made of tungsten wire to make corona discharge less likely to occur and form the unpolarized region 20b.
例えば、コロナ電極６０自体の長さを、圧電体層２０の幅（ワイヤー状のコロナ電極の長手方向の幅）よりも短くして、圧電体層２０の、コロナ電極６０と対面しない領域にコロナ放電を生じさせずに未分極領域２０ｂを形成するようにしてもよい。あるいは、コロナ電極６０の一部をタングステンワイヤーにしてコロナ放電を生じにくくして未分極領域２０ｂを形成するようにしてもよい。 In the example shown in FIG. 11, a part of the
For example, the length of the
図１２は、圧電体層の一方の電極層とは反対側の主面上の一部に絶縁体またはアースに接続された導電体を配置することで、分極処理される領域を規制する方法を説明するための図である。
図１２に示すように、圧電積層体１２ｂの圧電体層２０の第１電極層２４とは反対側の表面（上面）に対面して、この表面に沿って移動可能なワイヤー状のコロナ電極６０を配置する。圧電体層２０とコロナ電極６０との間隔は例えば１ｍｍ程度である。このコロナ電極６０と第１電極層２４とを直流電源に接続し、直流電源から第１電極層２４とコロナ電極６０との間に、数ｋＶ、例えば、６ｋＶの直流電圧を印加してコロナ放電を生じさせる。さらに、間隔を維持した状態で、圧電体層２０の上面に沿って、コロナ電極６０を移動（走査）して、圧電体層２０の分極処理を行う。これにより、圧電体層２０は厚さ方向に分極される。 FIG. 12 shows a method of regulating the area to be polarized by placing an insulator or a conductor connected to ground on a part of the main surface of the piezoelectric layer opposite to one electrode layer. It is a figure for explaining.
As shown in FIG. 12, a wire-shapedcorona electrode 60 faces the surface (top surface) of the piezoelectric layer 20 of the piezoelectric laminate 12b opposite to the first electrode layer 24 and is movable along this surface. Place. The distance between the piezoelectric layer 20 and the corona electrode 60 is, for example, about 1 mm. This corona electrode 60 and the first electrode layer 24 are connected to a DC power source, and a DC voltage of several kV, for example, 6 kV is applied between the first electrode layer 24 and the corona electrode 60 from the DC power source to discharge the corona. cause Further, the corona electrode 60 is moved (scanned) along the upper surface of the piezoelectric layer 20 while maintaining the interval to polarize the piezoelectric layer 20. Thereby, the piezoelectric layer 20 is polarized in the thickness direction.
図１２に示すように、圧電積層体１２ｂの圧電体層２０の第１電極層２４とは反対側の表面（上面）に対面して、この表面に沿って移動可能なワイヤー状のコロナ電極６０を配置する。圧電体層２０とコロナ電極６０との間隔は例えば１ｍｍ程度である。このコロナ電極６０と第１電極層２４とを直流電源に接続し、直流電源から第１電極層２４とコロナ電極６０との間に、数ｋＶ、例えば、６ｋＶの直流電圧を印加してコロナ放電を生じさせる。さらに、間隔を維持した状態で、圧電体層２０の上面に沿って、コロナ電極６０を移動（走査）して、圧電体層２０の分極処理を行う。これにより、圧電体層２０は厚さ方向に分極される。 FIG. 12 shows a method of regulating the area to be polarized by placing an insulator or a conductor connected to ground on a part of the main surface of the piezoelectric layer opposite to one electrode layer. It is a figure for explaining.
As shown in FIG. 12, a wire-shaped
その際、図１２に示すように、圧電体層２０の上面の一部を、絶縁性またはアースに接続された導電性の第２被覆部材６４で覆うことにより、第２被覆部材６４で覆った領域にはコロナ放電を生じさせず、あるいは、コロナ放電に晒される領域を規制して、分極処理されることを防止する。これにより、圧電体層２０に未分極領域２０ｂと分極領域２０ａとを形成することができる。
At this time, as shown in FIG. 12, a part of the upper surface of the piezoelectric layer 20 is covered with an insulating or conductive second covering member 64 connected to the ground. Corona discharge is not generated in the region, or the region exposed to corona discharge is regulated to prevent it from being polarized. Thereby, unpolarized regions 20b and polarized regions 20a can be formed in the piezoelectric layer 20.
第２被覆部材６４の位置、長さ等は、圧電体層２０において未分極領域２０ｂを形成する領域に合わせて適宜設定すればよい。
The position, length, etc. of the second covering member 64 may be appropriately set according to the area in the piezoelectric layer 20 where the unpolarized area 20b is formed.
絶縁性の第２被覆部材６４としては、アルミナ、ゴムシート等を用いることができる。
また、導電性の第２被覆部材６４としては、銅箔シート等を用いることができる。なお、導電性の第２被覆部材６４を用いる場合には、第２被覆部材６４はアースに接続される。 As the insulating second coveringmember 64, alumina, a rubber sheet, etc. can be used.
Further, as the conductivesecond covering member 64, a copper foil sheet or the like can be used. Note that when using the conductive second covering member 64, the second covering member 64 is connected to ground.
また、導電性の第２被覆部材６４としては、銅箔シート等を用いることができる。なお、導電性の第２被覆部材６４を用いる場合には、第２被覆部材６４はアースに接続される。 As the insulating second covering
Further, as the conductive
分極処理工程の後には、図１３に示すように、分極処理を行った圧電積層体１２ｂの圧電体層２０側に、先に準備したシート状物１２ｃを、第１電極層２４を圧電体層２０に向けて積層する。
さらに、この積層体を、第１保護層２８および第２保護層３０を挟持するようにして、加熱プレス装置および加熱ローラ等を用いて熱圧着して、圧電積層体１２ｂとシート状物１２ｃとを貼り合わせ、図８に示すような、圧電フィルム１０を作製する。
あるいは、圧電積層体１２ｂとシート状物１２ｃとを、接着剤を用いて貼り合わせて、好ましくは、さらに圧着して、圧電フィルム１０を作製してもよい。 After the polarization treatment step, as shown in FIG. Stack toward 20.
Furthermore, this laminate is thermocompressed using a hot press device, a heating roller, etc., with the firstprotective layer 28 and the second protective layer 30 sandwiched therebetween, thereby forming the piezoelectric laminate 12b and the sheet-like material 12c. are bonded together to produce a piezoelectric film 10 as shown in FIG.
Alternatively, thepiezoelectric film 10 may be produced by bonding the piezoelectric laminate 12b and the sheet-like material 12c together using an adhesive, and preferably further press-bonding them.
さらに、この積層体を、第１保護層２８および第２保護層３０を挟持するようにして、加熱プレス装置および加熱ローラ等を用いて熱圧着して、圧電積層体１２ｂとシート状物１２ｃとを貼り合わせ、図８に示すような、圧電フィルム１０を作製する。
あるいは、圧電積層体１２ｂとシート状物１２ｃとを、接着剤を用いて貼り合わせて、好ましくは、さらに圧着して、圧電フィルム１０を作製してもよい。 After the polarization treatment step, as shown in FIG. Stack toward 20.
Furthermore, this laminate is thermocompressed using a hot press device, a heating roller, etc., with the first
Alternatively, the
なお、この圧電フィルム１０は、カットシート状のシート状物１２ａおよびシート状物１２ｃ等を用いて製造してもよく、あるいは、ロール・トゥ・ロール（Ｒｏｌｌ ｔｏ Ｒｏｌｌ）を利用して製造してもよい。
Note that this piezoelectric film 10 may be manufactured using a cut sheet-like sheet material 12a, a sheet-like material 12c, etc., or may be manufactured using a roll-to-roll method. Good too.
作製された圧電フィルムは、各種用途に合わせて、所望の形状に裁断されてもよい。
このようにして作製される圧電フィルム１０の分極領域は、面方向ではなく厚さ方向に分極されており、かつ、分極処理後に延伸処理をしなくても大きな圧電特性が得られる。そのため、圧電フィルム１０の分極領域は、圧電特性に面内異方性がなく、駆動電圧を印加すると、面方向では全方向に等方的に伸縮する。 The produced piezoelectric film may be cut into desired shapes according to various uses.
The polarized region of thepiezoelectric film 10 produced in this way is polarized not in the plane direction but in the thickness direction, and great piezoelectric properties can be obtained even without stretching treatment after polarization treatment. Therefore, the polarized region of the piezoelectric film 10 has no in-plane anisotropy in its piezoelectric properties, and when a driving voltage is applied, it expands and contracts isotropically in all directions in the plane.
このようにして作製される圧電フィルム１０の分極領域は、面方向ではなく厚さ方向に分極されており、かつ、分極処理後に延伸処理をしなくても大きな圧電特性が得られる。そのため、圧電フィルム１０の分極領域は、圧電特性に面内異方性がなく、駆動電圧を印加すると、面方向では全方向に等方的に伸縮する。 The produced piezoelectric film may be cut into desired shapes according to various uses.
The polarized region of the
ここで、上述したように、圧電体層２０は、マトリックス３４に圧電体粒子３６を含むものである。また、圧電体層２０を厚さ方向で挟むように、第２電極層２６および第１電極層２４が設けられる。
このような圧電体層２０を有する圧電フィルム１０の第２電極層２６および第１電極層２４に電圧を印加すると、分極領域２０ａにおいては、印加した電圧に応じて圧電体粒子３６が分極方向に伸縮する。その結果、圧電フィルム１０（圧電体層２０の分極領域２０ａ）が厚さ方向に収縮する。同時に、ポアゾン比の関係で、圧電フィルム１０は、面内方向にも伸縮する。この伸縮は、０．０１～０．１％程度である。 Here, as described above, thepiezoelectric layer 20 includes piezoelectric particles 36 in the matrix 34. Further, a second electrode layer 26 and a first electrode layer 24 are provided so as to sandwich the piezoelectric layer 20 in the thickness direction.
When a voltage is applied to thesecond electrode layer 26 and the first electrode layer 24 of the piezoelectric film 10 having such a piezoelectric layer 20, in the polarization region 20a, the piezoelectric particles 36 move in the polarization direction according to the applied voltage. Expand and contract. As a result, the piezoelectric film 10 (polarized region 20a of the piezoelectric layer 20) contracts in the thickness direction. At the same time, the piezoelectric film 10 also expands and contracts in the in-plane direction due to the Poisson ratio. This expansion/contraction is approximately 0.01 to 0.1%.
このような圧電体層２０を有する圧電フィルム１０の第２電極層２６および第１電極層２４に電圧を印加すると、分極領域２０ａにおいては、印加した電圧に応じて圧電体粒子３６が分極方向に伸縮する。その結果、圧電フィルム１０（圧電体層２０の分極領域２０ａ）が厚さ方向に収縮する。同時に、ポアゾン比の関係で、圧電フィルム１０は、面内方向にも伸縮する。この伸縮は、０．０１～０．１％程度である。 Here, as described above, the
When a voltage is applied to the
上述したように、圧電体層２０の厚さは、好ましくは１０～３００μｍ程度である。従って、厚さ方向の伸縮は、最大でも０．３μｍ程度と非常に小さい。
これに対して、圧電フィルム１０すなわち圧電体層２０（分極領域２０ａ）は、面方向には、厚さよりもはるかに大きなサイズを有する。従って、例えば、圧電フィルム１０の長さが２０ｃｍであれば、電圧の印加によって、最大で０．２ｍｍ程度、圧電フィルム１０は伸縮する。 As mentioned above, the thickness of thepiezoelectric layer 20 is preferably about 10 to 300 μm. Therefore, the expansion and contraction in the thickness direction is very small, about 0.3 μm at most.
On the other hand, thepiezoelectric film 10, that is, the piezoelectric layer 20 (polarized region 20a) has a size much larger than its thickness in the plane direction. Therefore, for example, if the length of the piezoelectric film 10 is 20 cm, the piezoelectric film 10 expands and contracts by a maximum of about 0.2 mm by applying a voltage.
これに対して、圧電フィルム１０すなわち圧電体層２０（分極領域２０ａ）は、面方向には、厚さよりもはるかに大きなサイズを有する。従って、例えば、圧電フィルム１０の長さが２０ｃｍであれば、電圧の印加によって、最大で０．２ｍｍ程度、圧電フィルム１０は伸縮する。 As mentioned above, the thickness of the
On the other hand, the
振動板１０２は、貼着層によって圧電フィルム１０に貼着されている。従って、圧電フィルム１０の伸縮によって、振動板１０２は撓み、その結果、振動板１０２は、厚さ方向に振動する。
この厚さ方向の振動によって、振動板１０２は、音を発生する。すなわち、振動板１０２は、圧電フィルム１０に印加した電圧（駆動電圧）の大きさに応じて振動して、圧電フィルム１０に印加した駆動電圧に応じた音を発生する。 Thediaphragm 102 is attached to the piezoelectric film 10 with an adhesive layer. Therefore, the diaphragm 102 is bent by the expansion and contraction of the piezoelectric film 10, and as a result, the diaphragm 102 vibrates in the thickness direction.
Due to this vibration in the thickness direction, thediaphragm 102 generates sound. That is, the diaphragm 102 vibrates according to the magnitude of the voltage (driving voltage) applied to the piezoelectric film 10 and generates sound according to the driving voltage applied to the piezoelectric film 10.
この厚さ方向の振動によって、振動板１０２は、音を発生する。すなわち、振動板１０２は、圧電フィルム１０に印加した電圧（駆動電圧）の大きさに応じて振動して、圧電フィルム１０に印加した駆動電圧に応じた音を発生する。 The
Due to this vibration in the thickness direction, the
また、振動板１０２のばね定数に応じて、圧電フィルム１０の質量を調整することで、音圧レベルを向上させることができる。圧電フィルム１０の質量が大きいと、振動板１０２が撓んでしまうため、駆動時の振動板１０２の振動を抑制する可能性がある。一方、圧電フィルム１０の質量が小さいと、共振周波数が高くなり、低周波数における振動板１０２の振動を抑制する可能性がある。これらの点を考慮すると、圧電フィルム１０の質量は、振動板１０２のばね定数に応じて、適切に調整することが好ましい。
Furthermore, by adjusting the mass of the piezoelectric film 10 according to the spring constant of the diaphragm 102, the sound pressure level can be improved. If the mass of the piezoelectric film 10 is large, the diaphragm 102 will bend, which may suppress the vibration of the diaphragm 102 during driving. On the other hand, when the mass of the piezoelectric film 10 is small, the resonance frequency becomes high, and vibration of the diaphragm 102 at low frequencies may be suppressed. Considering these points, it is preferable that the mass of the piezoelectric film 10 is appropriately adjusted according to the spring constant of the diaphragm 102.
以上、本発明の圧電素子について詳細に説明したが、本発明は上述の例に限定はされず、本発明の要旨を逸脱しない範囲において、各種の改良や変更を行ってもよいのは、もちろんである。
Although the piezoelectric element of the present invention has been described in detail above, the present invention is not limited to the above-mentioned examples, and it goes without saying that various improvements and changes may be made without departing from the gist of the present invention. It is.
以下、本発明の具体的実施例を挙げ、本発明についてより詳細に説明する。なお、本発明はこの実施例に限定されるものでなく、以下の実施例に示す材料、使用量、割合、処理内容、処理手順などは、本発明の趣旨を逸脱しない限り適宜変更することができる。
Hereinafter, the present invention will be explained in more detail by giving specific examples of the present invention. It should be noted that the present invention is not limited to this example, and the materials, usage amounts, ratios, processing contents, processing procedures, etc. shown in the following examples may be changed as appropriate without departing from the spirit of the present invention. can.
［実施例１］
＜圧電フィルムの作製＞
上述した図９～図１３に示す方法によって、圧電フィルムを作製した。
まず、下記の組成比で、シアノエチル化ＰＶＡ（ＣＲ－Ｖ 信越化学工業社製）をジメチルホルムアミド（ＤＭＦ）に溶解した。その後、この溶液に、圧電体粒子としてＰＺＴ粒子を下記の組成比で添加して、プロペラミキサー（回転数２０００ｒｐｍ）で攪拌して、圧電体層を形成するための塗料を調製した。
・ＰＺＴ粒子・・・・・・・・・・・３００質量部
・シアノエチル化ＰＶＡ・・・・・・・３０質量部
・ＤＭＦ・・・・・・・・・・・・・・７０質量部
なお、ＰＺＴ粒子は、市販のＰＺＴ原料粉を１０００～１２００℃で焼結した後、これを平均粒径５μｍになるように解砕および分級処理したものを用いた。 [Example 1]
<Preparation of piezoelectric film>
A piezoelectric film was produced by the method shown in FIGS. 9 to 13 described above.
First, cyanoethylated PVA (CR-V, manufactured by Shin-Etsu Chemical Co., Ltd.) was dissolved in dimethylformamide (DMF) at the composition ratio shown below. Thereafter, PZT particles as piezoelectric particles were added to this solution in the composition ratio shown below, and the mixture was stirred with a propeller mixer (rotation speed: 2000 rpm) to prepare a paint for forming a piezoelectric layer.
・PZT particles・・・・・・・・・300 parts by mass ・Cyanoethylated PVA・・・・・・30 parts by mass ・DMF・・・・・・・・・70 parts by mass The PZT particles used were obtained by sintering commercially available PZT raw material powder at 1000 to 1200° C., and then crushing and classifying it to an average particle size of 5 μm.
＜圧電フィルムの作製＞
上述した図９～図１３に示す方法によって、圧電フィルムを作製した。
まず、下記の組成比で、シアノエチル化ＰＶＡ（ＣＲ－Ｖ 信越化学工業社製）をジメチルホルムアミド（ＤＭＦ）に溶解した。その後、この溶液に、圧電体粒子としてＰＺＴ粒子を下記の組成比で添加して、プロペラミキサー（回転数２０００ｒｐｍ）で攪拌して、圧電体層を形成するための塗料を調製した。
・ＰＺＴ粒子・・・・・・・・・・・３００質量部
・シアノエチル化ＰＶＡ・・・・・・・３０質量部
・ＤＭＦ・・・・・・・・・・・・・・７０質量部
なお、ＰＺＴ粒子は、市販のＰＺＴ原料粉を１０００～１２００℃で焼結した後、これを平均粒径５μｍになるように解砕および分級処理したものを用いた。 [Example 1]
<Preparation of piezoelectric film>
A piezoelectric film was produced by the method shown in FIGS. 9 to 13 described above.
First, cyanoethylated PVA (CR-V, manufactured by Shin-Etsu Chemical Co., Ltd.) was dissolved in dimethylformamide (DMF) at the composition ratio shown below. Thereafter, PZT particles as piezoelectric particles were added to this solution in the composition ratio shown below, and the mixture was stirred with a propeller mixer (rotation speed: 2000 rpm) to prepare a paint for forming a piezoelectric layer.
・PZT particles・・・・・・・・・300 parts by mass ・Cyanoethylated PVA・・・・・・30 parts by mass ・DMF・・・・・・・・・70 parts by mass The PZT particles used were obtained by sintering commercially available PZT raw material powder at 1000 to 1200° C., and then crushing and classifying it to an average particle size of 5 μm.
一方、厚さ４μｍのＰＥＴフィルムに、厚さ０．３μｍの銅薄膜を真空蒸着してなる枚葉状のシート状物を用意した。すなわち、本例においては、第１電極層および第２電極層は、厚さ０．３μｍの銅蒸着薄膜であり、第１保護層および第２保護層は、厚さ４μｍのＰＥＴフィルムとなる。
シート状物の第１電極層（銅蒸着薄膜）の上に、スライドコーターを用いて、先に調製した圧電体層を形成するための塗料を塗布した。なお、塗料は、乾燥後の塗膜の膜厚が５０μｍになるように、塗布した。
次いで、シート状物に塗料を塗布した物を、１２０℃のホットプレート上で加熱乾燥することでＤＭＦを蒸発させた。これにより、ＰＥＴ製の第１保護層の上に銅製の第１電極層を有し、その上に、厚さが５０μｍの圧電体層（高分子複合圧電体層）を有する圧電積層体を作製した。作製した圧電積層体を１７０ｍｍ×２００ｍｍの大きさに切り出した。 On the other hand, a sheet-like product was prepared by vacuum-depositing a 0.3 μm thick copper thin film onto a 4 μm thick PET film. That is, in this example, the first electrode layer and the second electrode layer are copper vapor deposited thin films with a thickness of 0.3 μm, and the first protective layer and the second protective layer are PET films with a thickness of 4 μm.
The previously prepared paint for forming the piezoelectric layer was applied onto the first electrode layer (copper deposited thin film) of the sheet using a slide coater. The coating material was applied so that the thickness of the coating film after drying was 50 μm.
Next, the sheet material coated with the paint was heated and dried on a hot plate at 120° C. to evaporate the DMF. As a result, a piezoelectric laminate having a first electrode layer made of copper on a first protective layer made of PET, and a piezoelectric layer (polymer composite piezoelectric layer) with a thickness of 50 μm on top of the first electrode layer was produced. did. The produced piezoelectric laminate was cut into a size of 170 mm x 200 mm.
シート状物の第１電極層（銅蒸着薄膜）の上に、スライドコーターを用いて、先に調製した圧電体層を形成するための塗料を塗布した。なお、塗料は、乾燥後の塗膜の膜厚が５０μｍになるように、塗布した。
次いで、シート状物に塗料を塗布した物を、１２０℃のホットプレート上で加熱乾燥することでＤＭＦを蒸発させた。これにより、ＰＥＴ製の第１保護層の上に銅製の第１電極層を有し、その上に、厚さが５０μｍの圧電体層（高分子複合圧電体層）を有する圧電積層体を作製した。作製した圧電積層体を１７０ｍｍ×２００ｍｍの大きさに切り出した。 On the other hand, a sheet-like product was prepared by vacuum-depositing a 0.3 μm thick copper thin film onto a 4 μm thick PET film. That is, in this example, the first electrode layer and the second electrode layer are copper vapor deposited thin films with a thickness of 0.3 μm, and the first protective layer and the second protective layer are PET films with a thickness of 4 μm.
The previously prepared paint for forming the piezoelectric layer was applied onto the first electrode layer (copper deposited thin film) of the sheet using a slide coater. The coating material was applied so that the thickness of the coating film after drying was 50 μm.
Next, the sheet material coated with the paint was heated and dried on a hot plate at 120° C. to evaporate the DMF. As a result, a piezoelectric laminate having a first electrode layer made of copper on a first protective layer made of PET, and a piezoelectric layer (polymer composite piezoelectric layer) with a thickness of 50 μm on top of the first electrode layer was produced. did. The produced piezoelectric laminate was cut into a size of 170 mm x 200 mm.
作製した圧電体層を、ワイヤー状のコロナ電極を用いるコロナポーリング処理によって、厚さ方向に分極処理した。
その際、圧電体層の上面の２００ｍｍの長さの端辺の１つに沿う幅２０ｍｍの領域を絶縁性の第２被覆部材（材質：ニトリルゴム）で覆って分極処理を行った。これにより、分極領域と未分極領域とを有する圧電体層を形成した。尚、第２被覆部材としては、ラバーマグネット（ゴム磁石）でも構わない。これは磁性材を主にゴム系（ニトリルゴム／アクリルゴム）バインダーと混合して押出し成形されたものであるが磁力を有するため、分極処理を金属ステージ上で行う場合などサンプルを容易にステージに固定できる点で好適である。 The produced piezoelectric layer was polarized in the thickness direction by corona poling using a wire-shaped corona electrode.
At that time, a 20 mm wide region along one of the 200 mm long edges of the top surface of the piezoelectric layer was covered with an insulating second covering member (material: nitrile rubber) to perform polarization treatment. As a result, a piezoelectric layer having polarized regions and unpolarized regions was formed. Note that a rubber magnet may be used as the second covering member. This is an extrusion molded product made by mixing a magnetic material with a mainly rubber-based (nitrile rubber/acrylic rubber) binder, and since it has magnetic force, it is easy to place the sample on a stage, such as when performing polarization treatment on a metal stage. This is suitable because it can be fixed.
その際、圧電体層の上面の２００ｍｍの長さの端辺の１つに沿う幅２０ｍｍの領域を絶縁性の第２被覆部材（材質：ニトリルゴム）で覆って分極処理を行った。これにより、分極領域と未分極領域とを有する圧電体層を形成した。尚、第２被覆部材としては、ラバーマグネット（ゴム磁石）でも構わない。これは磁性材を主にゴム系（ニトリルゴム／アクリルゴム）バインダーと混合して押出し成形されたものであるが磁力を有するため、分極処理を金属ステージ上で行う場合などサンプルを容易にステージに固定できる点で好適である。 The produced piezoelectric layer was polarized in the thickness direction by corona poling using a wire-shaped corona electrode.
At that time, a 20 mm wide region along one of the 200 mm long edges of the top surface of the piezoelectric layer was covered with an insulating second covering member (material: nitrile rubber) to perform polarization treatment. As a result, a piezoelectric layer having polarized regions and unpolarized regions was formed. Note that a rubber magnet may be used as the second covering member. This is an extrusion molded product made by mixing a magnetic material with a mainly rubber-based (nitrile rubber/acrylic rubber) binder, and since it has magnetic force, it is easy to place the sample on a stage, such as when performing polarization treatment on a metal stage. This is suitable because it can be fixed.
分極処理を行った圧電積層体の上に、第２電極層（銅薄膜側）を圧電体層に向けて、ＰＥＴフィルムに同薄膜を蒸着したシート状物を積層した。
次いで、圧電積層体とシート状物との積層体を、ラミネータ装置を用いて、温度１２０℃で熱圧着することで、圧電体層と第２電極層とを貼着して接着して、圧電フィルムを作製した。 On top of the polarized piezoelectric laminate, a sheet-like material in which the same thin film was deposited on a PET film was laminated with the second electrode layer (copper thin film side) facing the piezoelectric layer.
Next, the laminate of the piezoelectric laminate and the sheet-like material is thermocompression bonded at a temperature of 120°C using a laminator device, so that the piezoelectric layer and the second electrode layer are adhered and bonded to form a piezoelectric layer. A film was produced.
次いで、圧電積層体とシート状物との積層体を、ラミネータ装置を用いて、温度１２０℃で熱圧着することで、圧電体層と第２電極層とを貼着して接着して、圧電フィルムを作製した。 On top of the polarized piezoelectric laminate, a sheet-like material in which the same thin film was deposited on a PET film was laminated with the second electrode layer (copper thin film side) facing the piezoelectric layer.
Next, the laminate of the piezoelectric laminate and the sheet-like material is thermocompression bonded at a temperature of 120°C using a laminator device, so that the piezoelectric layer and the second electrode layer are adhered and bonded to form a piezoelectric layer. A film was produced.
作製した圧電フィルムを１７０ｍｍの辺の方向に２回折り返して、圧電フィルム同士を粘着層（アクリル系粘着剤）で積層して、長さ２００ｍｍ×幅５０ｍｍの積層部と、長さ２００ｍｍ×幅２０ｍｍの突出部を有する圧電素子を作製した。折り返しの際、未分極領域が突出部となるようにした。
The produced piezoelectric film was folded twice in the direction of the 170 mm side, and the piezoelectric films were laminated with an adhesive layer (acrylic adhesive) to form a laminated part with a length of 200 mm and a width of 50 mm, and a laminated part with a length of 200 mm and a width of 20 mm. A piezoelectric element having a protrusion was fabricated. When folded back, the unpolarized region became a protrusion.
［比較例１］
コロナポーリング処理を行う際に、圧電体層の上面を第２被覆部材で覆わずに全面を分極処理した以外は実施例１と同様にして、圧電フィルムを作製して圧電素子を作製した。 [Comparative example 1]
A piezoelectric film was produced to produce a piezoelectric element in the same manner as in Example 1, except that when performing the corona poling treatment, the entire surface of the piezoelectric layer was polarized without covering it with the second covering member.
コロナポーリング処理を行う際に、圧電体層の上面を第２被覆部材で覆わずに全面を分極処理した以外は実施例１と同様にして、圧電フィルムを作製して圧電素子を作製した。 [Comparative example 1]
A piezoelectric film was produced to produce a piezoelectric element in the same manner as in Example 1, except that when performing the corona poling treatment, the entire surface of the piezoelectric layer was polarized without covering it with the second covering member.
［評価］
＜音質＞
作製した実施例および比較例の圧電素子を振動板に貼着し、電気音響変換器を作製した。振動板としては、大きさ５００ｍｍ×４５０ｍｍ、厚さ０．８ｍｍ、材質：アルミニウム（Ａ５０５２）の板状部材を用いた。振動板の横方向と圧電素子の長手方向を一致させて、振動板の中央に圧電素子の積層部の中心を合わせて貼着した。圧電素子と振動板とを貼着する貼着層としては、アクリル系粘着剤を用いた。 [evaluation]
<Sound quality>
The produced piezoelectric elements of Examples and Comparative Examples were adhered to a diaphragm to produce electroacoustic transducers. As the diaphragm, a plate-like member having a size of 500 mm x 450 mm, a thickness of 0.8 mm, and made of aluminum (A5052) was used. The transverse direction of the diaphragm and the longitudinal direction of the piezoelectric element were aligned, and the piezoelectric element was attached with the center of the laminated portion of the piezoelectric element aligned with the center of the diaphragm. An acrylic adhesive was used as the adhesive layer that adheres the piezoelectric element and the diaphragm.
＜音質＞
作製した実施例および比較例の圧電素子を振動板に貼着し、電気音響変換器を作製した。振動板としては、大きさ５００ｍｍ×４５０ｍｍ、厚さ０．８ｍｍ、材質：アルミニウム（Ａ５０５２）の板状部材を用いた。振動板の横方向と圧電素子の長手方向を一致させて、振動板の中央に圧電素子の積層部の中心を合わせて貼着した。圧電素子と振動板とを貼着する貼着層としては、アクリル系粘着剤を用いた。 [evaluation]
<Sound quality>
The produced piezoelectric elements of Examples and Comparative Examples were adhered to a diaphragm to produce electroacoustic transducers. As the diaphragm, a plate-like member having a size of 500 mm x 450 mm, a thickness of 0.8 mm, and made of aluminum (A5052) was used. The transverse direction of the diaphragm and the longitudinal direction of the piezoelectric element were aligned, and the piezoelectric element was attached with the center of the laminated portion of the piezoelectric element aligned with the center of the diaphragm. An acrylic adhesive was used as the adhesive layer that adheres the piezoelectric element and the diaphragm.
圧電素子に市販のＣＤ音源を用いて音楽信号をアンプを経由して入力し、振動板の正面１メートルの場所で官能評価を行い音質を１０段階評価で評価した。計２０人の試験者の平均点を表１に示す。
結果を表１に示す。 A music signal was input to the piezoelectric element via an amplifier using a commercially available CD sound source, and a sensory evaluation was performed at a location 1 meter in front of the diaphragm to evaluate the sound quality on a 10-point scale. Table 1 shows the average scores of a total of 20 testers.
The results are shown in Table 1.
結果を表１に示す。 A music signal was input to the piezoelectric element via an amplifier using a commercially available CD sound source, and a sensory evaluation was performed at a location 1 meter in front of the diaphragm to evaluate the sound quality on a 10-point scale. Table 1 shows the average scores of a total of 20 testers.
The results are shown in Table 1.
表１から、本発明の実施例は比較例に比べて音質が向上していることがわかる。これはノイズが少ないためである。実施例は、突出部を未分極領域としたことで、突出部が好き勝手に振動することが無くなり、ノイズ成分が低減されたことに起因して音質が向上している。
From Table 1, it can be seen that the sound quality of the examples of the present invention is improved compared to the comparative examples. This is because there is less noise. In the example, by making the protrusion into an unpolarized region, the protrusion does not vibrate arbitrarily, and noise components are reduced, resulting in improved sound quality.
［実施例２］
大きさを５０ｍｍ×２００ｍｍとし、コロナポーリング処理を行う際に、圧電体層の上面の４つの端辺それぞれに沿って幅３ｍｍの絶縁性の第２被覆部材（材質：ニトリルゴム）を配置して分極処理を行った以外は実施例１と同様にして圧電フィルムを作製した。 [Example 2]
The size was 50 mm x 200 mm, and when performing corona poling treatment, a 3 mm wide insulating second covering member (material: nitrile rubber) was placed along each of the four edges of the top surface of the piezoelectric layer. A piezoelectric film was produced in the same manner as in Example 1 except that the polarization treatment was performed.
大きさを５０ｍｍ×２００ｍｍとし、コロナポーリング処理を行う際に、圧電体層の上面の４つの端辺それぞれに沿って幅３ｍｍの絶縁性の第２被覆部材（材質：ニトリルゴム）を配置して分極処理を行った以外は実施例１と同様にして圧電フィルムを作製した。 [Example 2]
The size was 50 mm x 200 mm, and when performing corona poling treatment, a 3 mm wide insulating second covering member (material: nitrile rubber) was placed along each of the four edges of the top surface of the piezoelectric layer. A piezoelectric film was produced in the same manner as in Example 1 except that the polarization treatment was performed.
［比較例２］
コロナポーリング処理を行う際に、圧電体層の上面を第２被覆部材で覆わずに全面を分極処理した以外は実施例２と同様にして、圧電フィルムを作製した。 [Comparative example 2]
A piezoelectric film was produced in the same manner as in Example 2, except that when performing the corona poling treatment, the upper surface of the piezoelectric layer was not covered with the second covering member and the entire surface was subjected to the polarization treatment.
コロナポーリング処理を行う際に、圧電体層の上面を第２被覆部材で覆わずに全面を分極処理した以外は実施例２と同様にして、圧電フィルムを作製した。 [Comparative example 2]
A piezoelectric film was produced in the same manner as in Example 2, except that when performing the corona poling treatment, the upper surface of the piezoelectric layer was not covered with the second covering member and the entire surface was subjected to the polarization treatment.
［評価］
＜音質、外観異常（剥離）＞
作製した実施例および比較例の圧電フィルムを振動板に貼着し、電気音響変換器を作製した。振動板としては、大きさ５００ｍｍ×４５０ｍｍ、厚さ０．８ｍｍ、材質：アルミニウム（Ａ５０５２）の板状部材を用いた。振動板の横方向と圧電フィルムの長手方向を一致させて、振動板の中央に圧電フィルムの中心を合わせて貼着した。圧電フィルムと振動板とを貼着する貼着層としては、ホットメルト系接着シート（クラボウ社社製 クランベター）を用いた。貼着層の厚さは３０μｍとした。 [evaluation]
<Sound quality, appearance abnormality (peeling)>
The produced piezoelectric films of Examples and Comparative Examples were adhered to a diaphragm to produce electroacoustic transducers. As the diaphragm, a plate-like member having a size of 500 mm x 450 mm, a thickness of 0.8 mm, and made of aluminum (A5052) was used. The lateral direction of the diaphragm and the longitudinal direction of the piezoelectric film were aligned, and the piezoelectric film was attached with the center of the diaphragm aligned with the center of the diaphragm. A hot melt adhesive sheet (Cranbetter, manufactured by Kurabo Industries, Ltd.) was used as the adhesive layer for adhering the piezoelectric film and the diaphragm. The thickness of the adhesive layer was 30 μm.
＜音質、外観異常（剥離）＞
作製した実施例および比較例の圧電フィルムを振動板に貼着し、電気音響変換器を作製した。振動板としては、大きさ５００ｍｍ×４５０ｍｍ、厚さ０．８ｍｍ、材質：アルミニウム（Ａ５０５２）の板状部材を用いた。振動板の横方向と圧電フィルムの長手方向を一致させて、振動板の中央に圧電フィルムの中心を合わせて貼着した。圧電フィルムと振動板とを貼着する貼着層としては、ホットメルト系接着シート（クラボウ社社製 クランベター）を用いた。貼着層の厚さは３０μｍとした。 [evaluation]
<Sound quality, appearance abnormality (peeling)>
The produced piezoelectric films of Examples and Comparative Examples were adhered to a diaphragm to produce electroacoustic transducers. As the diaphragm, a plate-like member having a size of 500 mm x 450 mm, a thickness of 0.8 mm, and made of aluminum (A5052) was used. The lateral direction of the diaphragm and the longitudinal direction of the piezoelectric film were aligned, and the piezoelectric film was attached with the center of the diaphragm aligned with the center of the diaphragm. A hot melt adhesive sheet (Cranbetter, manufactured by Kurabo Industries, Ltd.) was used as the adhesive layer for adhering the piezoelectric film and the diaphragm. The thickness of the adhesive layer was 30 μm.
圧電フィルムにノイズ信号発生器を用いてピンクノイズ信号をアンプ経由で入力し、１万時間連続で駆動し、試験前後での音圧変化、外観異常の有無を調べた。
結果を表２に示す。 A pink noise signal was input to the piezoelectric film via an amplifier using a noise signal generator, and the piezoelectric film was driven continuously for 10,000 hours to examine changes in sound pressure and appearance abnormalities before and after the test.
The results are shown in Table 2.
結果を表２に示す。 A pink noise signal was input to the piezoelectric film via an amplifier using a noise signal generator, and the piezoelectric film was driven continuously for 10,000 hours to examine changes in sound pressure and appearance abnormalities before and after the test.
The results are shown in Table 2.
表２から、本発明の実施例は比較例に比べて音圧が低下しておらず、外観異常がないことがわかる。すなわち、本発明の実施例は、比較例に比べて剥離しにくい圧電フィルムが振動板から剥離しにくいことがわかる。
比較例１は、圧電フィルムと振動板との貼着面の外周端部で剥離が発生していた。また、比較例１は、この剥離に伴い、音圧が低下したものと考えられる。
以上から本発明の効果は明らかである。 From Table 2, it can be seen that the sound pressure of the examples of the present invention is not lower than that of the comparative examples, and there is no abnormality in appearance. That is, it can be seen that in the examples of the present invention, the piezoelectric film, which is difficult to peel off, is difficult to peel off from the diaphragm, compared to the comparative examples.
In Comparative Example 1, peeling occurred at the outer peripheral edge of the bonding surface between the piezoelectric film and the diaphragm. Further, in Comparative Example 1, it is considered that the sound pressure decreased due to this peeling.
From the above, the effects of the present invention are clear.
比較例１は、圧電フィルムと振動板との貼着面の外周端部で剥離が発生していた。また、比較例１は、この剥離に伴い、音圧が低下したものと考えられる。
以上から本発明の効果は明らかである。 From Table 2, it can be seen that the sound pressure of the examples of the present invention is not lower than that of the comparative examples, and there is no abnormality in appearance. That is, it can be seen that in the examples of the present invention, the piezoelectric film, which is difficult to peel off, is difficult to peel off from the diaphragm, compared to the comparative examples.
In Comparative Example 1, peeling occurred at the outer peripheral edge of the bonding surface between the piezoelectric film and the diaphragm. Further, in Comparative Example 1, it is considered that the sound pressure decreased due to this peeling.
From the above, the effects of the present invention are clear.
本発明の圧電フィルムおよび圧電素子は、例えば、音波センサー、超音波センサー、圧力センサー、触覚センサー、歪みセンサーおよび振動センサー等の各種センサー(特に、ひび検知等のインフラ点検や異物混入検知等の製造現場検査に有用である)、マイクロフォン、ピックアップ、スピーカーおよびエキサイター等の音響デバイス（具体的な用途としては、ノイズキャンセラー(車、電車、飛行機、ロボット等に使用)、人工声帯、害虫・害獣侵入防止用ブザー、家具、壁紙、写真、ヘルメット、ゴーグル、ヘッドレスト、サイネージ、ロボットなどが例示される）、自動車、スマートフォン、スマートウォッチ、ゲーム等に適用して用いるハプティクス、超音波探触子およびハイドロホン等の超音波トランスデューサ、水滴付着防止、輸送、攪拌、分散、研磨等に用いるアクチュエータ、容器、乗り物、建物、スキーおよびラケット等のスポーツ用具に用いる制振材（ダンパー）、ならびに、道路、床、マットレス、椅子、靴、タイヤ、車輪およびパソコンキーボード等に適用して用いる振動発電装置として好適に使用することができる。
The piezoelectric film and piezoelectric element of the present invention can be used, for example, in the manufacture of various sensors such as sonic sensors, ultrasonic sensors, pressure sensors, tactile sensors, strain sensors, and vibration sensors (particularly for infrastructure inspections such as crack detection and foreign object detection). (Useful for on-site inspections), acoustic devices such as microphones, pickups, speakers, and exciters (Specific applications include noise cancellers (used in cars, trains, airplanes, robots, etc.), artificial vocal cords, and pest/vermin intrusion. Examples include protective buzzers, furniture, wallpaper, photographs, helmets, goggles, headrests, signage, robots, etc.), haptics, ultrasonic probes, and hydrophones used in automobiles, smartphones, smart watches, games, etc. ultrasonic transducers such as, actuators used for water droplet prevention, transportation, stirring, dispersion, polishing, etc., vibration dampers used for containers, vehicles, buildings, sports equipment such as skis and rackets, and roads, floors, etc. It can be suitably used as a vibration power generation device for use in mattresses, chairs, shoes, tires, wheels, computer keyboards, and the like.
１０ａ、１０ｂ 圧電フィルム
１１ａ 積層部
１１ｂ 突出部
１２ａ、１２ｃ シート状物
１２ｂ 圧電積層体
１４ 粘着層
２０ 圧電体層
２０ａ 分極領域
２０ｂ 未分極領域
２４ 第１電極層
２６ 第２電極層
２８ 第１保護層
３０ 第２保護層
３４ マトリックス
３６ 圧電体粒子
４０、４２ 導線
５０ 圧電素子
６０ コロナ電極
６２ 第１被覆部材
６４ 第２被覆部材
１００ａ、１００ｂ 電気音響変換器
１０２ 振動板 10a,10b piezoelectric film 11a laminated portion 11b protruding portion 12a, 12c sheet-like material 12b piezoelectric laminate 14 adhesive layer 20 piezoelectric layer 20a polarized region 20b unpolarized region 24 first electrode layer 26 second electrode layer 28 first protective layer 30 second protective layer 34 matrix 36 piezoelectric particles 40, 42 conducting wire 50 piezoelectric element 60 corona electrode 62 first covering member 64 second covering member 100a, 100b electroacoustic transducer 102 diaphragm
１１ａ 積層部
１１ｂ 突出部
１２ａ、１２ｃ シート状物
１２ｂ 圧電積層体
１４ 粘着層
２０ 圧電体層
２０ａ 分極領域
２０ｂ 未分極領域
２４ 第１電極層
２６ 第２電極層
２８ 第１保護層
３０ 第２保護層
３４ マトリックス
３６ 圧電体粒子
４０、４２ 導線
５０ 圧電素子
６０ コロナ電極
６２ 第１被覆部材
６４ 第２被覆部材
１００ａ、１００ｂ 電気音響変換器
１０２ 振動板 10a,
Claims (12)
- 高分子材料を含むマトリックス中に圧電体粒子を含む高分子複合圧電体からなる圧電体層と、前記圧電体層の両面に設けられる電極層と、を有する圧電フィルムにおいて、
前記圧電体層が一部に分極されていない未分極領域を有する、圧電フィルム。 A piezoelectric film having a piezoelectric layer made of a polymer composite piezoelectric material containing piezoelectric particles in a matrix containing a polymer material, and electrode layers provided on both sides of the piezoelectric layer,
A piezoelectric film, wherein the piezoelectric layer has an unpolarized region in which the piezoelectric layer is not polarized. - 電極対を構成する一対の前記電極層に挟持された領域において、前記圧電体層が、厚さ方向に分極された分極領域と、前記未分極領域とを有する、請求項１に記載の圧電フィルム。 The piezoelectric film according to claim 1, wherein the piezoelectric layer has a polarized region polarized in the thickness direction and the unpolarized region in a region sandwiched between the pair of electrode layers constituting an electrode pair. .
- 前記未分極領域が、前記圧電フィルムの外縁部に存在する、請求項１に記載の圧電フィルム。 The piezoelectric film according to claim 1, wherein the unpolarized region is present at an outer edge of the piezoelectric film.
- 請求項１～３のいずれか一項に記載の圧電フィルムを１回以上、折り返すことにより、前記圧電フィルムを、複数層、積層してなる圧電素子であって、
平面視において、前記圧電フィルムが２層以上重なる積層部と、前記積層部から突出する突出部を有し、
前記突出部は、前記電極層と外部電源とを接続するための接続部を有し、
前記未分極領域が前記突出部に存在する、圧電素子。 A piezoelectric element formed by laminating a plurality of piezoelectric films by folding the piezoelectric film according to any one of claims 1 to 3 one or more times,
In a plan view, the piezoelectric film has a laminated part in which two or more layers overlap, and a protrusion part that protrudes from the laminated part,
The protruding portion has a connecting portion for connecting the electrode layer and an external power source,
A piezoelectric element, wherein the unpolarized region is present in the protrusion. - 請求項１～３のいずれか一項に記載の圧電フィルムを、振動板に貼り付けてなる、電気音響変換器。 An electroacoustic transducer comprising the piezoelectric film according to any one of claims 1 to 3 attached to a diaphragm.
- 請求項４に記載の圧電素子を、振動板に貼り付けてなる、電気音響変換器。 An electroacoustic transducer comprising the piezoelectric element according to claim 4 attached to a diaphragm.
- 前記圧電フィルムの前記電極層と、前記振動板とが電気的に接続されていない、請求項５に記載の電気音響変換器。 The electroacoustic transducer according to claim 5, wherein the electrode layer of the piezoelectric film and the diaphragm are not electrically connected.
- 前記圧電フィルムの前記電極層と、前記振動板とが電気的に接続されていない、請求項６に記載の電気音響変換器。 The electroacoustic transducer according to claim 6, wherein the electrode layer of the piezoelectric film and the diaphragm are not electrically connected.
- 高分子材料を含むマトリックス中に圧電体粒子を含む高分子複合圧電体からなる圧電体層と、前記圧電体層の両面に設けられる電極層と、を有する圧電フィルムの製造方法であって、
一方の前記電極層の主面に、未分極の前記圧電体層を形成する圧電体層形成工程と、
前記圧電体層形成工程の後に、前記圧電体層の一部を分極処理する分極処理工程と、
前記分極処理工程の後に、前記圧電体層の主面に他方の前記電極層を積層する電極積層工程と、を有し、
前記分極処理工程は、前記圧電体層の前記一方の電極層とは反対側の主面に対面して電極部材を配置して、前記一方の電極層をアースに接続した後、前記電極部材との間に直流電圧を印加して分極処理を行うものであり、
前記分極処理される領域を規制することにより、前記圧電体層に分極された分極領域と、分極されていない未分極領域とを形成する、圧電フィルムの製造方法。 A method for producing a piezoelectric film comprising: a piezoelectric layer made of a polymer composite piezoelectric material containing piezoelectric particles in a matrix containing a polymer material; and electrode layers provided on both sides of the piezoelectric layer.
a piezoelectric layer forming step of forming the unpolarized piezoelectric layer on the main surface of one of the electrode layers;
After the piezoelectric layer forming step, a polarization treatment step of polarizing a part of the piezoelectric layer;
After the polarization treatment step, an electrode lamination step of laminating the other electrode layer on the main surface of the piezoelectric layer,
In the polarization treatment step, after arranging an electrode member facing the main surface of the piezoelectric layer opposite to the one electrode layer and connecting the one electrode layer to ground, The polarization process is performed by applying a DC voltage between the
A method for manufacturing a piezoelectric film, wherein a polarized region and an unpolarized region are formed in the piezoelectric layer by regulating the region to be polarized. - 前記分極処理がコロナポーリング処理であり、
前記電極部材がワイヤー状のコロナ電極である、請求項９に記載の圧電フィルムの製造方法。 The polarization treatment is a corona poling treatment,
The method for manufacturing a piezoelectric film according to claim 9, wherein the electrode member is a wire-shaped corona electrode. - 前記分極処理工程において、ワイヤー状の前記コロナ電極の、前記コロナ放電が生じる領域の長さを前記圧電体層の幅よりも短くすることで、前記分極処理される領域を規制する、請求項１０に記載の圧電フィルムの製造方法。 10. In the polarization treatment step, the region to be polarized is regulated by making the length of the region of the wire-shaped corona electrode where the corona discharge occurs shorter than the width of the piezoelectric layer. A method for producing a piezoelectric film as described in .
- 前記分極処理工程において、前記圧電体層の前記一方の電極層とは反対側の主面上の一部に絶縁体またはアースに接続された導電体を配置することで、前記分極処理される領域を規制する、請求項９に記載の圧電フィルムの製造方法。 In the polarization treatment step, an insulator or a conductor connected to earth is placed on a part of the main surface of the piezoelectric layer opposite to the one electrode layer, so that the region to be polarized is The method for manufacturing a piezoelectric film according to claim 9, wherein the method regulates the following.
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Citations (3)
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| JP2017037875A (en) * | 2015-08-06 | 2017-02-16 | Tdk株式会社 | Piezoelectric element and piezoelectric actuator |
| WO2020196850A1 (en) * | 2019-03-28 | 2020-10-01 | 富士フイルム株式会社 | Piezoelectric film, layered piezoelectric element, and electroacoustic transducer |
| JP2021047819A (en) * | 2019-09-20 | 2021-03-25 | 株式会社ジャパンディスプレイ | Tactile device |
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| JP2017037875A (en) * | 2015-08-06 | 2017-02-16 | Tdk株式会社 | Piezoelectric element and piezoelectric actuator |
| WO2020196850A1 (en) * | 2019-03-28 | 2020-10-01 | 富士フイルム株式会社 | Piezoelectric film, layered piezoelectric element, and electroacoustic transducer |
| JP2021047819A (en) * | 2019-09-20 | 2021-03-25 | 株式会社ジャパンディスプレイ | Tactile device |
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