JP2018133412A - Piezoelectric device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric device in which output is less likely to be attenuated even when a load applied state is maintained.SOLUTION: A piezoelectric device 1 includes: a power storage element part 11; and a piezoelectric element part 12 overlaid on the power storage element part 11. In the power storage element part 11, plural dielectric films 2 which are disposed between a first conductive layer 31 and a second conductive layer 32 are laminated. In the piezoelectric element part 12, plural piezoelectric body films 4 which are disposed between a third conductive layer 33 and a fourth conductive layer 34 are laminated. The first conductive layer 31 and the third conductive layer 33 are electrically connected to each other, and the second conductive layer 32 and the fourth conductive layer 34 are electrically connected to each other. Since each of the plural piezoelectric body films 4 has a curved shape, the entire of the piezoelectric element part 12 has a curved shape.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a piezoelectric device including a piezoelectric film.

  As a piezoelectric device including a piezoelectric film such as a stretched polylactic acid film, for example, in Patent Document 1, a sensor that converts mechanical vibration into a voltage and detects the vibration, and vibration generated by applying a signal voltage to an electrode are disclosed. A piezoelectric speaker that has been used has been proposed. Such a piezoelectric device outputs a voltage according to the acceleration of displacement generated in itself. Therefore, for example, when a large load is momentarily applied to the piezoelectric device, the piezoelectric device outputs a large voltage.

JP 2014-27038 A

  The voltage output by the conventional piezoelectric device is quickly attenuated, and thereafter, the piezoelectric device does not output voltage even if the load is maintained. Therefore, it is difficult to detect that the load is maintained using a piezoelectric device.

  An object of the present invention is to provide a piezoelectric device in which an output is not easily attenuated even when a state where a load is applied is maintained.

  A piezoelectric device according to one embodiment of the present invention includes a power storage element portion and a piezoelectric element portion that overlaps the power storage element portion. A plurality of dielectric films sandwiched between the first conductive layer and the second conductive layer are laminated on the power storage element portion. A plurality of piezoelectric films sandwiched between the third conductive layer and the fourth conductive layer are laminated on the piezoelectric element portion. The first conductive layer and the third conductive layer are electrically connected, and the second conductive layer and the fourth conductive layer are electrically connected. Since the plurality of piezoelectric films all have a curved shape, the entire piezoelectric element portion has a curved shape.

  According to one embodiment of the present invention, it is possible to obtain a piezoelectric device in which output is hardly attenuated even when a state where a load is applied is maintained.

1A is a schematic perspective view showing a piezoelectric device according to an embodiment of the present invention, and FIG. 1B is a schematic cross-sectional view showing the piezoelectric device shown in FIG. 1A. 1B is a schematic perspective view showing an intermediate product for manufacturing the piezoelectric device shown in FIG. 1A. FIG. 3A is a schematic perspective view showing a process for producing an original member of the electricity storage element part in the intermediate product shown in FIG. 2, and FIG. 3B shows a process of producing an original member of the piezoelectric element part in the intermediate product shown in FIG. It is a schematic perspective view shown.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1A and 1B.

  The piezoelectric device 1 according to the present embodiment includes a power storage element unit 11 and a piezoelectric element unit 12 that overlaps the power storage element unit 11.

  A plurality of dielectric films 2 sandwiched between the first conductive layer 31 and the second conductive layer 32 are stacked on the power storage element portion 11. A plurality of piezoelectric films 4 sandwiched between the third conductive layer 33 and the fourth conductive layer 34 are laminated on the piezoelectric element portion 12.

  For example, in FIG. 1, the power storage element unit 11 includes a plurality of laminated dielectric films 2, and a first conductive layer 31 and a second conductive layer 32 that are stacked on each of the dielectric films 2. In addition, if the 1st conductive layer 31 and the 2nd conductive layer 32 are piled up on each of the dielectric films 2 except the dielectric film 2 located in the outermost direction of the lamination direction of the dielectric film 2, they are the outermost. The dielectric film 2 positioned at the position may only overlap one of the first conductive layer 31 and the second conductive layer 32. “Laminated” in this case means that a plurality of dielectric films 2 are arranged in the thickness direction in the electricity storage element portion 11, and in this case, the dielectric films 2 are in direct contact with each other. It does not have to be.

  The piezoelectric element unit 12 includes a plurality of stacked piezoelectric films 4 and a third conductive layer 33 and a fourth conductive layer 34 that are stacked on each of the piezoelectric films 4. If the third conductive layer 33 and the fourth conductive layer 34 are stacked on each of the piezoelectric films 4 excluding the piezoelectric film 4 positioned at the outermost position in the stacking direction of the piezoelectric films 4, The piezoelectric film 4 positioned at the position may overlap only with one of the third conductive layer 33 and the fourth conductive layer 34. In this case, “laminated” means that a plurality of piezoelectric films 4 are arranged in the thickness direction in the piezoelectric element portion 12. In this case, the piezoelectric films 4 are in direct contact with each other. It does not have to be.

  The first conductive layer 31 and the third conductive layer 33 are electrically connected, and the second conductive layer 32 and the fourth conductive layer 34 are electrically connected.

  Each of the plurality of piezoelectric films 4 has a curved shape, whereby the entire piezoelectric element portion 12 has a curved shape.

  According to the present embodiment, when the piezoelectric element portion 12 is deformed by a load, a voltage is generated in the piezoelectric element portion 12 due to the piezoelectric effect caused by the displacement of the piezoelectric film 4. Therefore, the piezoelectric device 1 can output a voltage corresponding to the load.

  In the present embodiment, as described above, the dielectric film 2 has a curved shape, so that the entire piezoelectric element portion 12 has a curved shape, which is the case when a load is applied. The charge generated at 12 can be increased. The electric charge generated in the piezoelectric element unit 12 is supplied to the electric storage element unit 11 and stored therein. For this reason, even if the load applied to the piezoelectric device 1 is maintained, the voltage output from the piezoelectric device 1 is not easily attenuated. Further, even when the acceleration of displacement of the piezoelectric film 4 is small, such as when the load applied to the piezoelectric device 1 gradually increases, the piezoelectric device 1 can output a sufficiently large voltage.

  Therefore, in the present embodiment, it can be detected using the piezoelectric device 1 that the load is maintained. Even when the load gradually increases, the load can be detected. Furthermore, in this embodiment, since the piezoelectric element portion 12 that exhibits the piezoelectric effect and the power storage element portion 11 that stores the charge generated by the piezoelectric effect are stacked in the piezoelectric device 1, the above functions are exhibited. The piezoelectric device 1 can be made compact, and the piezoelectric device 1 can be used to detect a load being maintained or a gradually increasing load without using other circuits or detectors. it can. The piezoelectric device 1 can also be used for power generation.

  The piezoelectric device 1 according to this embodiment includes, for example, traffic fields such as traffic sensors and tire pressure sensors, security fields such as intrusion detection and theft alarm, acoustic and ultrasonic fields such as acoustic pickups, fish finders, and sonars. It can be applied to various fields such as the medical field such as ultrasonic diagnosis and the field of floor power generation.

  The configuration of the piezoelectric device 1 will be described in more detail.

  In the present embodiment, as shown in FIG. 1A, the piezoelectric element portion has a curved shape so as to protrude toward the side opposite to the electricity storage element portion. The power storage element portion has a curved shape so as to protrude toward the piezoelectric element portion side. That is, in the present embodiment, each of the power storage element portion and the piezoelectric element portion has a curved shape so as to protrude in one direction from the power storage element portion to the piezoelectric element portion. Thereby, the whole piezoelectric device has a curved shape.

  In the present embodiment, the power storage element portion and the piezoelectric element portion are curved, and thus have an arc shape when viewed from one direction (hereinafter referred to as the X direction).

  First, the power storage element unit 11 will be described. The power storage element portion 11 can have the same structure as a general laminated film capacitor except that it has a curved shape when viewed from the X direction.

  In the present embodiment, the power storage element unit 11 includes a plurality of dielectric films 2 and a plurality of conductive layers 3. Dielectric films 2 and conductive layers 3 are arranged alternately. The conductive layer 3 includes a first conductive layer 31 and a second conductive layer 32, and the first conductive layer 31 and the second conductive layer 32 are arranged alternately. That is, in the electric storage element unit 11, the elements are repeated such as the first conductive layer 31, the dielectric film 2, the second conductive layer 32, the dielectric film 2, the first conductive layer 31, the dielectric film 2, and so on. They are stacked side by side. As a result, the storage element unit 11 includes a plurality of laminated dielectric films 2, and a first conductive layer 31 and a second conductive layer 32 that are stacked in contact with each of the dielectric films 2, and a dielectric Each of the body films 2 is sandwiched between the first conductive layer 31 and the second conductive layer 32. The thickness direction and the lamination direction of the dielectric film 2 and the conductive layer 3 are orthogonal to the X direction.

  In the present embodiment, each of the dielectric film 2, the first conductive layer 31, and the second conductive layer 32 is curved so that the shape seen from the X direction is an arc shape. Since the dielectric film 2, the first conductive layer 31, and the second conductive layer 32 are laminated in a direction orthogonal to the X direction, the entire storage element unit 11 is curved, and the storage element unit 11 has an arc shape. Have. The curvature of the arc shape of the dielectric film 2 is, for example, in the range of 1/10 to 1/2000 (1 / mm), preferably in the range of 1/20 to 1/1000 (1 / mm). This is not a limitation.

  The dielectric film 2 may be a film made of a dielectric. The dielectric film 2 is made of a plastic such as polyester, polycarbonate, polypropylene, or polystyrene. That is, the dielectric film 2 is, for example, a plastic film. In the present embodiment, the dielectric film 2 preferably does not have piezoelectricity, that is, the piezoelectric constant of the dielectric film 2 is preferably zero.

  The conductive layer 3 in the power storage element unit 11 may be a layer made of a conductor. The conductive layer 3 is, for example, at least one metal selected from the group consisting of indium, tin, zinc, gallium, antimony, titanium, silicon, zirconium, magnesium, aluminum, gold, silver, copper, palladium, and tungsten, or at least It is made from a kind of metal oxide.

  Although the number of the dielectric films 2 in the electrical storage element part 11 exists in the range of 20-1000, for example, it is not restrict | limited to this.

  Next, the piezoelectric element unit 12 will be described.

  In the present embodiment, the piezoelectric element unit 12 includes a plurality of piezoelectric films 4, a plurality of insulating films 8, and a plurality of conductive layers 3. The piezoelectric films 4 and the insulating films 8 are alternately arranged. The conductive layer 3 is interposed between the adjacent piezoelectric film 4 and the insulating film 8. The conductive layer 3 in the piezoelectric element portion 12 includes a third conductive layer 33 and a fourth conductive layer 34, and the third conductive layer 33 and the fourth conductive layer 34 are alternately arranged. That is, in the piezoelectric element portion 12, the elements are repeatedly arranged such as the third conductive layer 33, the piezoelectric film 4, the fourth conductive layer 34, the insulating film 8, the third conductive layer 33, the piezoelectric film 4,. Are stacked. As a result, the piezoelectric element portion 12 includes a plurality of stacked piezoelectric films 4, and a third conductive layer 33 and a fourth conductive layer 34 stacked in contact with each of the piezoelectric films 4. Each of the body films 4 is sandwiched between the third conductive layer 33 and the fourth conductive layer 34.

  In other words, in this embodiment, the piezoelectric element portion 12 includes the piezoelectric element 9 including the third conductive layer 33, the fourth conductive layer 34, and the piezoelectric film 4 sandwiched therebetween, and the insulating film 8. Are provided, and the piezoelectric elements 9 and the insulating films 8 are alternately stacked. The thickness direction and lamination direction of the piezoelectric film 4, the insulating film 8, and the conductive layer 3 are orthogonal to the X direction.

  In the present embodiment, each of the piezoelectric film 4, the insulating film 8, the third conductive layer 33, and the fourth conductive layer 34 is curved so that the shape viewed from the X direction is an arc shape. Since the piezoelectric film 4, the insulating film 8, the third conductive layer 33, and the fourth conductive layer 34 are laminated in a direction orthogonal to the X direction, the entire piezoelectric element unit 12 is curved, and the piezoelectric element unit 12 Has an arc shape. The curvature of the arc shape of the piezoelectric film 4 is, for example, in the range of 1/10 to 1/2000 (1 / mm), preferably in the range of 1/20 to 1/1000 (1 / mm). This is not a limitation.

  The piezoelectric film 4 may be a film made of a piezoelectric body. The piezoelectric film 4 is made of, for example, polyvinylidene fluoride (PVDF). The piezoelectric film 4 is made of vinylidene fluoride-trifluoride ethylene copolymer (VDF / TrFE), vinylidene fluoride-tetrafluoroethylene copolymer (VDF / TeFE), vinylidene cyanide-vinyl acetate copolymer. You may produce from the plastics which have piezoelectricity, such as unification (VDCN / VAc), nylon 11, polylactic acid, and polyurea. That is, the piezoelectric film 4 is a plastic film having piezoelectricity, for example.

  In addition, when the piezoelectric film 4 contains polylactic acid, since polylactic acid has biodegradability, the burden on the environment when discarding the piezoelectric device 1 can be reduced. The polylactic acid is, for example, poly L-lactic acid or poly D-lactic acid, and particularly preferably stretched poly L-lactic acid or stretched poly D-lactic acid. In this case, it is possible to obtain the piezoelectric film 4 having a property of being polarized in the thickness direction according to the displacement along the direction orthogonal to the thickness direction. The optical purity of polylactic acid is preferably 80 mol% or more, more preferably 90 mol% or more, particularly preferably 95 mol% or more, and most preferably 98 mol% or more. Polylactic acid may contain units other than lactic acid in its molecular structure, but the ratio of units other than lactic acid to the total of units derived from lactic acid and units other than lactic acid is 10 mol% or less. Is preferably 5 mol% or less, more preferably 2 mol% or less.

  The insulating film 8 may be a film having electrical insulation. The insulating film 8 is made of an electrically insulating plastic such as a polypropylene resin such as biaxially stretched polypropylene or a polyethylene resin such as polyethylene terephthalate (PET). That is, the insulating film 8 is a plastic film having electrical insulation, for example. The thickness of the insulating film 8 is, for example, in the range of 1 to 20 μm, preferably in the range of 3 to 9 μm.

  The conductive layer 3 in the piezoelectric element portion 12 may be a layer made of a conductor. The conductive layer 3 is, for example, at least one metal selected from the group consisting of indium, tin, zinc, gallium, antimony, titanium, silicon, zirconium, magnesium, aluminum, gold, silver, copper, palladium, and tungsten, or at least It is made from a kind of metal oxide.

  The number of piezoelectric films 4 in the piezoelectric element portion 12 is, for example, in the range of 40 to 1000, but is not particularly limited thereto.

  The thickness of the piezoelectric element portion 12 is preferably smaller than the thickness of the electricity storage element portion 11. In this case, since the piezoelectric element unit 12 is more easily deformed than the power storage element unit 11, the displacement of the piezoelectric element unit 12 when subjected to a load is increased, thereby improving the output of the piezoelectric device 1. Specifically, the thickness of the electricity storage element portion 11 is preferably in the range of 0.5 to 25 mm, while the thickness of the piezoelectric element portion 12 is in the range of 0.1 to 20 mm. Is preferred. The thickness of the piezoelectric element portion 12 is preferably in the range of 10 to 90% of the thickness of the electricity storage element portion 11.

  The thickness of the piezoelectric film 4 is preferably larger than the thickness of the dielectric film 2, that is, the thickness of the dielectric film 2 is preferably smaller than the thickness of the piezoelectric film 4. In general, since the strength of a plastic film having piezoelectricity is weak, if the thickness of the piezoelectric film 4 is small, the piezoelectric film 4 is easily damaged by a load, and as a result, the output of the piezoelectric device 1 decreases. There is a risk of it. However, when the thickness of the piezoelectric film 4 is large, damage to the piezoelectric film 4 can be suppressed. Moreover, if the thickness of the dielectric film 2 is small, the electrostatic capacitance of the electrical storage element part 11 will become large, As a result, attenuation | damping of the output of the piezoelectric device 1 when a load is maintained will be suppressed more.

  Specifically, the thickness of the piezoelectric film 4 is preferably in the range of 3 to 200 μm, and more preferably in the range of 5 to 50 μm. Moreover, it is preferable that the thickness of the dielectric film 2 exists in the range of 1-20 micrometers, and if it exists in the range of 2-9 micrometers, it is still more preferable. The thickness of the piezoelectric film 4 is also preferably in the range of 110 to 10000% of the thickness of the dielectric film 2.

  Note that when the thickness of the piezoelectric film 4 is reduced, the capacitance of the piezoelectric element portion 12 is increased, so that it can be expected that the output is less likely to be attenuated when the load is maintained. The film 4 is easily damaged. Increasing the number of piezoelectric films 4 can increase the capacitance of the piezoelectric element portion 12, but in this case, the thickness of the piezoelectric element portion 12 is increased, and the piezoelectric element portion 12 with respect to the load is increased. The amount of displacement will be small. On the other hand, in this embodiment, since the piezoelectric element portion 12 overlaps the power storage element portion 11, the output from the piezoelectric device 1 when the load is maintained is attenuated regardless of the thickness and number of the piezoelectric films 4. It can be difficult.

  The dielectric loss tangent of the piezoelectric film 4 is preferably larger than the dielectric loss tangent of the dielectric film 2. That is, the dielectric loss tangent of the dielectric film 2 is preferably smaller than the dielectric loss tangent of the piezoelectric film 4. When the dielectric loss tangent of the dielectric film 2 is small, the composite dielectric loss tangent in the power storage element unit 11 can be reduced. Therefore, heat generation at the time of charge / discharge in the electricity storage element unit 11 can be suppressed.

  Specifically, the dielectric loss tangent of the piezoelectric film 4 is preferably in the range of 0.04 to 0.2. The dielectric loss tangent of the dielectric film 2 is preferably in the range of 0.0005 to 0.015, and the smaller the value, the better.

  The thicknesses of the third conductive layer 33 and the fourth conductive layer 34 in the piezoelectric element portion 12 are preferably larger than the thicknesses of the first conductive layer 31 and the second conductive layer 32 in the power storage element portion 11. If the thicknesses of the third conductive layer 33 and the fourth conductive layer 34 are large, the internal resistance in the piezoelectric element portion 12 can be reduced, and the strength of the piezoelectric element portion 12 that is a portion that deforms under a load can be improved. .

  The thicknesses of the first conductive layer 31, the second conductive layer 32, the third conductive layer 33, and the fourth conductive layer 34 are used to suppress the surface resistance value of these conductive layers 3, and to manufacture the power storage element unit 11 and the piezoelectric element unit 12. It is preferably determined in consideration of the properties, maintenance of interlayer strength in the electricity storage element portion 11 and the piezoelectric element portion 12, and damage suppression when the conductive layer 3 is manufactured.

  Specifically, the thickness of the first conductive layer 31 and the second conductive layer 32 is preferably in the range of 10 nm to 5 μm. Moreover, it is preferable that the thickness of the 3rd conductive layer 33 and the 4th conductive layer 34 exists in the range of 10 nm-5 micrometers.

  As described above, the piezoelectric element portion 12 is overlaid on the power storage element portion 11. In this case, the stacking direction of the dielectric film 2 in the power storage element unit 11, the stacking direction of the piezoelectric film 4 in the piezoelectric element unit 12, and the stacking direction of the power storage element unit 11 and the piezoelectric element unit 12 are all the same. . Further, the arc-shaped center of the electric storage element unit 11, the arc-shaped center of the dielectric film 2, the arc-shaped center axis of the piezoelectric element unit 12, and the arc-shaped center axis of the piezoelectric film 4 are: It almost matches.

  The piezoelectric element unit 12 and the storage element unit 11 are electrically insulated from the surface of the piezoelectric element unit 12 that faces the storage element unit 11 and the surface of the storage element unit 11 that faces the piezoelectric element unit 12. So that they are laminated. In the present embodiment, the piezoelectric device 1 includes an elastic member 13 interposed between the electricity storage element unit 11 and the piezoelectric element unit 12. That is, the elastic member 13 is interposed between the power storage element portion 11 and the piezoelectric element portion 12. The elastic member 13 can be insulated. In addition, when the piezoelectric device 1 includes the elastic member 13, when the piezoelectric element portion 12 is deformed by a load, the elastic member 13 easily deforms following the deformation, and thus the piezoelectric element portion 12 overlaps the power storage element portion 11. However, the piezoelectric element portion 12 is easily deformed. Therefore, the voltage generated in the piezoelectric element portion 12 in accordance with the load increases, and as a result, the output of the piezoelectric device 1 with respect to the load is improved.

  The elastic member 13 is not particularly limited as long as it is a member having an elastic limit strain higher than that of the power storage element portion 11. The elastic member 13 includes, for example, nitrile rubber, fluorine rubber, silicone rubber, natural rubber, isoprene rubber, butyl rubber, acrylic rubber, urethane rubber, ethylene propylene rubber, epichlorohydrin rubber, styrene butadiene rubber, butadiene rubber, norbornene rubber, latex, and heat. It is a sheet or a foamed sheet made from at least one material selected from the group consisting of plastic elastomers. The thickness of the elastic member 13 is in the range of 0.5 to 5 mm, for example.

  The piezoelectric device 1 may not include the elastic member 13 as described above. In that case, for example, the conductive layer 3 in the piezoelectric element section 12 and the dielectric film 2 in the power storage element section 11 are in contact with each other, or the piezoelectric film 4 or the insulating film 8 in the piezoelectric element section 12 and the power storage element section 11 are overlapped. The conductive layer 3 contacts and overlaps, or the piezoelectric film 4 or the insulating film 8 in the piezoelectric element portion 12 and the dielectric film 2 in the energy storage element portion 11 contact and overlap each other, whereby the power storage element portion 11 of the piezoelectric element portion 12. Is electrically insulated from the surface facing the piezoelectric element portion 12 of the electricity storage element portion 11. Further, a member having electrical insulation other than the elastic member 13 may be interposed between the piezoelectric element portion 12 and the power storage element portion 11.

  In the present embodiment, the piezoelectric device 1 includes a first external electrode 61 and a second external electrode 62. These configurations will be described.

  As described above, the first conductive layer 31 and the third conductive layer 33 are electrically connected, and the second conductive layer 32 and the fourth conductive layer 34 are electrically connected. In the present embodiment, the piezoelectric device 1 has a first end 51 and a second end 52 on the opposite side of the first end 51, and the first external electrode 61 is provided on the first end 51. A second external electrode 62 is provided at the second end 52. The first external electrode 61 is electrically connected to both the first conductive layer 31 and the third conductive layer 33 to electrically connect the first conductive layer 31 and the third conductive layer 33. ing. In addition, the second external electrode 62 is electrically connected to both the second conductive layer 32 and the fourth conductive layer 34, thereby electrically connecting the second conductive layer 32 and the fourth conductive layer 34. Connected. From the first external electrode 61 and the second external electrode 62, the output of the piezoelectric device 1 can be taken out.

  In the present embodiment, the first end 51 is one end in the X direction of the piezoelectric device 1. The second end 52 is an end opposite to the first end 51.

  In the present embodiment, the first conductive layer 31 is exposed on the surface on the first end portion 51 side of the power storage element portion 11, and the third conductive layer 33 is exposed on the surface on the first end portion 51 side of the piezoelectric element portion 12. ing. The first external electrode 61 is in contact with the surface on the first end portion 51 side of the power storage element portion 11 and the surface on the first end portion 51 side of the piezoelectric element portion 12. It is in contact with both the one conductive layer 31 and the third conductive layer 33. For this reason, the first external electrode 61 is electrically connected to both the first conductive layer 31 and the third conductive layer 33.

  In the present embodiment, the second conductive layer 32 is exposed on the surface on the second end 52 side of the power storage element portion 11, and the fourth conductive layer 34 is exposed on the surface on the second end 52 side of the piezoelectric element portion 12. Exposed. The second external electrode 62 is in contact with the surface on the second end 52 side of the electricity storage element portion 11 and the surface on the second end 52 side of the piezoelectric element portion 12, whereby the second external electrode 62 is It is in contact with both the second conductive layer 32 and the fourth conductive layer 34. For this reason, the second external electrode 62 is electrically connected to both the second conductive layer 32 and the fourth conductive layer 34.

  The first external electrode 61 and the second external electrode 62 are selected from the group consisting of, for example, aluminum, zinc, tin, lead, nickel, iron, copper, and brass, and an alloy of two or more of these metals. Made from at least one material. The first external electrode 61 and the second external electrode 62 may be made of an easily deformable material such as conductive rubber. The first external electrode 61 and the second external electrode 62 may be made from a conductive paste, a conductive adhesive, or a conductive sheet.

  An example of a method for manufacturing the piezoelectric device 1 will be described.

  First, as shown in FIG. 2, the piezoelectric device includes the original member 110 of the power storage element unit 11, the original member 120 of the piezoelectric element unit 12, the original member 610 of the first external electrode 61, and the original member 620 of the second external electrode 62. The intermediate product 10 of the device 1 is produced. The original member 110, the original member 120, the original member 610, and the original member 620 are, when the piezoelectric device 1 is manufactured from the intermediate product 10, the electric storage element unit 11, the piezoelectric element unit 12, the first external electrode 61, and the second external electrode, respectively. It is a member that becomes the electrode 62.

  As a method for producing the original member 110 of the power storage element unit 11, a general method for producing a wound film capacitor can be employed. For example, first, a coating for improving adhesion is applied to one surface of the long first dielectric film 21 as necessary, and then the first conductive layer 31 is formed by a method such as vapor deposition or sputtering. . Thereby, the 1st metallized film 15 provided with the 1st dielectric film 21 and the 1st conductive layer 31 is produced. In addition, after applying a coating for improving adhesion on one surface of the long second dielectric film 22 as necessary, the second conductive layer 32 is produced by a method such as vapor deposition or sputtering. Thereby, the 2nd metallized film 16 provided with the 2nd dielectric film 22 and the 2nd conductive layer 32 is produced. In a state in which the first metallized film 15 and the second metallized film 16 are overlapped, the power storage element unit 11 is wound by winding them around a central axis along one direction (hereinafter referred to as Y direction). The original member 110 can be produced. The original member 110 has, for example, a tube shape having a central axis along the Y direction. In addition to the vapor deposition method and the sputtering method, for example, by applying a conductive paste on one surface of the dielectric film 2, applying a conductive adhesive, or stacking a conductive sheet such as a metal foil, Layer 3 may be produced. The Y direction coincides with the X direction in the piezoelectric device 1.

  In the description so far, the first conductive layer 31 is formed on one side of the first dielectric film 21, and the second conductive layer 32 is formed on one side of the second dielectric film 21, but the present invention is not limited to this. For example, the first conductive layer 31 is formed on one main surface of the first dielectric film 21, the second conductive layer 32 is formed on the other main surface, and the second conductive layer 3 is not formed. The dielectric film 22 may be wound.

  An elastic member 13 is disposed around the original member 110 of the electricity storage element unit 11 as necessary.

  As a manufacturing method of the original member 120 of the piezoelectric element portion 12, a method according to a general manufacturing method of a wound film capacitor can be adopted. For example, first, a coating for improving adhesion is applied on one surface of the long piezoelectric film 4 as necessary, and then the conductive layer 3 is produced by a method such as vapor deposition or sputtering. Thereby, the 3rd metallized film 17 provided with the piezoelectric material film 4 and the conductive layer 3 is produced. Moreover, after applying a coating for improving adhesion on one surface of the long insulating film 8 as necessary, the conductive layer 3 is produced by a method such as vapor deposition or sputtering. Thereby, the 4th metallized film 18 provided with the insulating film 8 and the conductive layer 3 is produced. Subsequently, in a state where the third metallized film 17 and the fourth metallized film 18 are overlapped, they are wound around the original member 110 of the electric storage element unit 11 around the central axis along the Y direction. Thus, the original member 120 of the piezoelectric element portion 12 can be manufactured. The original member 120 has, for example, a tube shape having a central axis along the Y direction. In addition to the vapor deposition method and the sputtering method, for example, a conductive paste is applied on one surface of the piezoelectric film 4 or the insulating film 8, a conductive adhesive is applied, or a conductive sheet such as a metal foil is stacked. By doing so, the conductive layer 3 may be fabricated.

  In the above description, the conductive layer 3 is formed on one side of the piezoelectric film 4 and the conductive layer 3 is formed on one side of the insulating film 8, but the present invention is not limited to this. For example, the conductive layer 3 is formed on one main surface of the piezoelectric film 4 and the insulating film 8, and the conductive layer 3 is not formed on the other main surface. The insulating film 8 may be wound.

  The original member 610 of the first external electrode 61 and the original member 620 of the second external electrode 62 are provided at one end and the other end of the original member 110 and the original member 120 in the Y direction, respectively. The original member 610 and the original member 620 are, for example, at least one material selected from the group consisting of aluminum, zinc, tin, lead, nickel, iron, copper, and brass, and an alloy of two or more of these metals. Made from. The original member 610 and the original member 620 are produced by a method such as metallicon, plating, or vapor deposition, for example. The original member 610 and the original member 620 may be made of an easily deformable material such as conductive rubber. The first external electrode 61 and the second external electrode 62 may be manufactured by applying a material such as a conductive paste or a conductive adhesive, or by bonding a conductive sheet.

  In this way, an intermediate product 10 having a tubular shape having a central axis along the Y direction as shown in FIG. 3 can be produced. A plurality of piezoelectric devices 1 can be manufactured from one intermediate product 10 by cutting the intermediate product 10 at, for example, a plurality of locations along a plane parallel to the Y direction.

  The first external electrode 61 and the second external electrode 62 are produced after the original member 110 and the original member 120 are cut without producing the original member 610 and the original member 620, whereby the piezoelectric device 1 is produced. May be.

DESCRIPTION OF SYMBOLS 1 Piezoelectric device 11 Power storage element part 12 Piezoelectric element part 13 Elastic member 2 Dielectric film 31 1st conductive layer 32 2nd conductive layer 33 3rd conductive layer 34 4th conductive layer 4 Piezoelectric film 51 1st end part 52 2nd End 61 First external electrode 62 Second external electrode

Claims (10)

A power storage element part, and a piezoelectric element part overlapping the power storage element part,
A plurality of dielectric films sandwiched between the first conductive layer and the second conductive layer are laminated on the power storage element portion,
In the piezoelectric element portion, a plurality of piezoelectric films sandwiched between a third conductive layer and a fourth conductive layer are laminated,
The first conductive layer and the third conductive layer are electrically connected, the second conductive layer and the fourth conductive layer are electrically connected,
Since the plurality of piezoelectric films have a curved shape, the entire piezoelectric element portion has a curved shape.
Piezoelectric device. The piezoelectric element portion has a curved shape so as to protrude toward the opposite side of the electricity storage element portion.
The piezoelectric device according to claim 1. The power storage element portion has a curved shape so as to protrude toward the piezoelectric element portion side.
The piezoelectric device according to claim 2. The thickness of the piezoelectric element portion is smaller than the thickness of the electricity storage element portion,
The piezoelectric device according to any one of claims 1 to 3. The thickness of the piezoelectric film is larger than the thickness of the dielectric film,
The piezoelectric device according to any one of claims 1 to 4. The dielectric loss tangent of the piezoelectric film is larger than the dielectric loss tangent of the dielectric film,
The piezoelectric device according to any one of claims 1 to 5. Having a first end and a second end opposite to the first end;
A first external electrode at the first end, and a second external electrode at the second end,
The first external electrode is electrically connected to both the first conductive layer and the third conductive layer, thereby electrically connecting the first conductive layer and the third conductive layer. ,
The second external electrode is electrically connected to both the second conductive layer and the fourth conductive layer, thereby electrically connecting the second conductive layer and the fourth conductive layer. ing,
The piezoelectric device according to any one of claims 1 to 6. The thickness of each of the third conductive layer and the fourth conductive layer is greater than the thickness of each of the first conductive layer and the second conductive layer.
The piezoelectric device according to any one of claims 1 to 7. Comprising an elastic body interposed between the electricity storage element portion and the piezoelectric element portion;
The piezoelectric device according to any one of claims 1 to 8. The plurality of piezoelectric films contain polylactic acid,
The piezoelectric device according to any one of claims 1 to 9.

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