JPWO2019078053A1 - Piezoelectric device and its manufacturing method - Google Patents

Abstract

Even if a plurality of piezoelectric layers having the same piezoelectric characteristics are laminated and the opposing surfaces of adjacent piezoelectric layers are not electrically insulated, a voltage corresponding to the tensile force when a tensile force is applied. A piezoelectric device capable of producing a piezoelectric device and a method for manufacturing the same. In the piezoelectric device (1), a plurality of piezoelectric layers (10) included in the first group and a plurality of piezoelectric layers (20) included in the second group are alternately arranged and laminated to form an adjacent piezoelectric layer (10). A conductive layer (30) is interposed between the piezoelectric layer (20). The piezoelectric layer (10) included in the first group and the piezoelectric layer (20) included in the second group are stretched resin films having the same piezoelectric characteristics. The stretching directions of the piezoelectric layers (10) included in the first group are all in the same direction, and the stretching directions of the piezoelectric layers (20) included in the second group are all in the same direction. The stretching direction of the piezoelectric layer (10) included in the first group intersects with the stretching direction of the piezoelectric layer (20) included in the second group.

Description

The present disclosure relates to a piezoelectric device and a method for manufacturing the same, and more particularly to a piezoelectric device in which a plurality of piezoelectric layers are laminated and a method for manufacturing the same.

Conventionally, a piezoelectric layer made of a stretched resin film having piezoelectricity and a conductive layer are laminated to produce a piezoelectric device. In such a piezoelectric device, when a tensile force or the like is applied, the piezoelectric layer is polarized. Therefore, the voltage can be taken out from the conductive layer.

For example, in Patent Document 1, a piezoelectric layer made of a stretched resin film of poly L-lactic acid resin and a piezoelectric layer made of a stretched resin film of poly D-lactic acid resin, which is an optical isomer of poly L-lactic acid resin, are conductive. A piezoelectric device in which layers are alternately laminated is disclosed.

Japanese Unexamined Patent Publication No. 2012-232497

However, since the piezoelectric device disclosed in Patent Document 1 requires two types of piezoelectric layers having different piezoelectric characteristics, the piezoelectric film has poor productivity, is costly, and has the same characteristics without optical isomers. However, there was a problem that a piezoelectric device having the same structure could not be realized.

On the other hand, when a piezoelectric layer made of a resin film having the same piezoelectric characteristics is laminated to produce a piezoelectric device and a tensile force or the like is applied to the piezoelectric device, the opposing surfaces of the adjacent piezoelectric layers differ from each other due to polarization. Charges are generated. Therefore, when the conductive layers are interposed between the adjacent piezoelectric layers to electrically connect the facing surfaces of the piezoelectric layers, the electric charges generated in the piezoelectric layers are canceled. Therefore, an insulating layer must be provided between the opposing surfaces of the piezoelectric layer to electrically insulate the opposing surfaces of the piezoelectric layer, and the size of the piezoelectric device is increased by the thickness of the insulating layer. turn into. Therefore, there is a problem that it is not suitable for miniaturization and weight reduction of the piezoelectric device.

An object of the present disclosure is that even if a plurality of piezoelectric layers having the same piezoelectric characteristics are laminated and the opposing surfaces of adjacent piezoelectric layers are not electrically insulated, a force is applied when a force is applied. It is an object of the present invention to provide a piezoelectric device capable of generating a voltage according to the above and a method for manufacturing the same.

The piezoelectric device according to one aspect of the present disclosure includes a piezoelectric layer included in the first group, a piezoelectric layer included in the second group, and a conductive layer. The piezoelectric layers included in the first group and the piezoelectric layers included in the second group are alternately laminated. A conductive layer is interposed between the piezoelectric layers included in the first group and the piezoelectric layers included in the second group, which are adjacent to each other in the stacking direction. The piezoelectric layer included in the first group and the piezoelectric layer included in the second group are stretched resin films. The piezoelectric layer included in the first group and the piezoelectric layer included in the second group are a tensile force direction with respect to a stretching direction when a tensile force is applied, and a polarization direction of the piezoelectric layer generated by the tensile force. It has piezoelectric properties in which the relationships are the same as each other. The stretching directions of the piezoelectric layers included in the first group are all in the same direction. The stretching directions of the piezoelectric layers included in the second group are all the same direction. The stretching direction of the piezoelectric layer included in the first group and the stretching direction of the piezoelectric layer included in the second group intersect.

Further, in the method for manufacturing a piezoelectric device according to one aspect of the present disclosure, a first film material and a second film material are prepared. Each of the first film material and the second film material includes a stretched resin film. At least one of the first film material and the second film material further includes a conductive film that overlaps the stretched resin film. The stretched resin film of the first film material and the stretched resin film of the second film material have a relationship between the direction of the tensile force with respect to the stretching direction when a tensile force is applied and the direction of polarization generated by the tensile force. However, they have piezoelectric characteristics that are the same as each other. In the manufacturing method, the first film material and the second film material are crossed so that the stretching direction of the stretched resin film of the first film material and the stretching direction of the stretched resin film of the second film material intersect. Including weaving and folding.

According to one aspect of the present disclosure, a force is applied even if a plurality of piezoelectric layers having the same piezoelectric characteristics are laminated and the opposing surfaces of adjacent piezoelectric layers are not electrically insulated. A piezoelectric device capable of generating a voltage depending on the force can be obtained.

FIG. 1 is a schematic cross-sectional view showing a piezoelectric device according to the first embodiment of the present disclosure. FIG. 2 is an exploded perspective view showing an outline of the piezoelectric device according to the first embodiment of the present disclosure. FIG. 3A is a schematic view showing the upper surface of the first film material in the first embodiment. FIG. 3B is a schematic view showing the lower surface of the first film material in the first embodiment. FIG. 3C is a schematic view showing the upper surface of the second film material. FIG. 3D is a schematic view showing the lower surface of the second film material. FIG. 3E is a side view showing an example of the first film material and the second film material. FIG. 4A is a schematic view showing an example of braided folding in the method for manufacturing a piezoelectric device according to the first embodiment of the present disclosure. FIG. 4B is a schematic view showing an example of braided folding in the method for manufacturing a piezoelectric device according to the first embodiment of the present disclosure. FIG. 4C is a schematic view showing an example of braided folding in the method for manufacturing a piezoelectric device according to the first embodiment of the present disclosure. FIG. 4D is a diagram showing an example of an intermediate product produced by braiding and folding. FIG. 4E is a cross-sectional view of the intermediate product as viewed from the side. FIG. 5A is a schematic cross-sectional view showing the piezoelectric device according to the second embodiment of the present invention. FIG. 5B is an exploded perspective view showing an outline of the piezoelectric device according to the second embodiment. FIG. 6A is a schematic view showing the upper surfaces of the first film material and the second film material in the second embodiment. FIG. 6B is a schematic view showing the lower surfaces of the first film material and the second film material in the second embodiment. FIG. 7A is a schematic view showing an example of braided folding in the method for manufacturing a piezoelectric device according to the second embodiment of the present disclosure. FIG. 7B is a schematic view showing an example of braided folding in the method for manufacturing a piezoelectric device according to the second embodiment of the present disclosure. FIG. 7C is a schematic view showing an example of braided folding in the method for manufacturing a piezoelectric device according to the second embodiment of the present disclosure. FIG. 7D is a diagram showing an example of an intermediate product produced by braiding and folding. FIG. 8A is a schematic cross-sectional view showing the piezoelectric device according to the third embodiment of the present disclosure. FIG. 8B is an exploded perspective view showing an outline of the piezoelectric device according to the third embodiment. FIG. 9A is a schematic view showing the upper surface of the first film material in the third embodiment. FIG. 9B is a schematic view showing the lower surface of the first film material in the third embodiment. FIG. 9C is a schematic view showing the upper surface of the second film material in the third embodiment. FIG. 9D is a schematic view showing the lower surface of the second film material in the third embodiment. FIG. 10A is a schematic view showing an example of braided folding in the method for manufacturing a piezoelectric device according to the third embodiment of the present disclosure. FIG. 10B is a schematic view showing an example of braided folding in the method for manufacturing a piezoelectric device according to the third embodiment of the present disclosure. FIG. 10C is a schematic view showing an example of braided folding in the method for manufacturing a piezoelectric device according to the third embodiment of the present disclosure. FIG. 10D is a diagram showing an example of an intermediate product produced by braiding and folding. FIG. 11A is a schematic view showing an example of the electrode pattern of the conductive film on the first film material and the second film material and the marking on the conductive film. FIG. 11B is a schematic view showing an example of the electrode pattern of the conductive film on the first film material and the second film material and the marking on the conductive film. FIG. 11C is a schematic view showing an example of the electrode pattern of the conductive film on the first film material and the second film material and the marking on the conductive film. FIG. 11D is a schematic view showing an example of the electrode pattern of the conductive film on the first film material and the second film material and the marking on the conductive film. FIG. 11E is a schematic view showing an example of the electrode pattern of the conductive film on the first film material and the second film material and the marking on the conductive film. FIG. 11F is a schematic view showing an example of the electrode pattern of the conductive film on the first film material and the second film material and the marking on the conductive film. FIG. 11G is a diagram showing an example of the position of the terminal portion when the piezoelectric device is viewed from above. FIG. 12 is a schematic view for explaining the piezoelectric characteristics.

First, an outline of the configuration of the piezoelectric device according to the embodiment of the present disclosure will be described with reference to FIG.

The piezoelectric device 1 according to the present embodiment includes a piezoelectric layer 10 included in the first group (hereinafter, also simply referred to as a piezoelectric layer 10) and a piezoelectric layer 20 included in a second group (hereinafter, also simply referred to as a piezoelectric layer 20). ) And are stacked alternately. A conductive layer 30 is interposed between the adjacent piezoelectric layers 10 and the piezoelectric layer 20. The piezoelectric layer 10 and the piezoelectric layer 20 are both stretched resin films. The piezoelectric layer 10 and the piezoelectric layer 20 have piezoelectric characteristics in which the relationship between the direction of the tensile force with respect to the stretching direction when a tensile force is applied and the polarization direction of the piezoelectric layer generated by the tensile force is the same as each other. .. The stretching directions of the piezoelectric layer 10 are all the same. The stretching directions of the piezoelectric layer 20 are all the same. The stretching direction of the piezoelectric layer 10 and the stretching direction of the piezoelectric layer 20 intersect.

In the description in the specification, the "piezoelectric property" is a property of the piezoelectric layer in which polarization is generated according to the tensile force when a tensile force is applied, and this property is determined by the direction of the tensile force and the tensile force. The relationship with the direction of the resulting polarization is also included. The piezoelectric layer 10 which is a stretched resin film and the piezoelectric layer 20 which is a stretched resin film have the same piezoelectric characteristics as each other. That is, the relationship between the tensile force direction with respect to the stretching direction when a tensile force is applied to the piezoelectric layer 10 and the piezoelectric layer 20 and the polarization direction of the piezoelectric layer 10 and the piezoelectric layer 20 generated by the tensile force is both. It is the same.

More specifically, when the piezoelectric layer 10 and the piezoelectric layer 20 have the same piezoelectric characteristics with reference to FIG. 12, for example, the piezoelectric layer 10 and the piezoelectric layer 20 have the following configurations. Both the piezoelectric layer 10 and the piezoelectric layer 20 are stretched resin films having a thickness and being stretched in one direction (the direction of + X in FIG. 12) orthogonal to the thickness direction. In both the piezoelectric layer 10 and the piezoelectric layer 20, a surface facing in one direction along the thickness is defined as an upper surface, and a surface facing in a direction opposite to the upper surface is defined as a lower surface. The terms of the upper surface and the lower surface do not regulate the postures of the piezoelectric layer 10 and the piezoelectric layer 20. When a tensile force is applied to the piezoelectric layer 10 in a direction in which the piezoelectric layer 10 is inclined with respect to the stretching direction (+ X direction), the piezoelectric layer 10 is polarized. Even if a tensile force is applied to the piezoelectric layer 20 in a direction in which the piezoelectric layer 20 is inclined with respect to the stretching direction (+ X direction), the piezoelectric layer 20 is polarized. When a tensile force is applied to the piezoelectric layer 10 in a direction inclined clockwise when viewed from the upper surface side (+ Y direction in FIG. 12) with respect to the stretching direction (+ X direction) of the piezoelectric layer 10. Polarization occurs in the direction (+ Z direction in FIG. 12) so that the upper surface of 10 is positively charged. Even when a tensile force is applied to the piezoelectric layer 20 in a direction (+ Y direction) inclined clockwise when viewed from the upper surface side with respect to the stretching direction (+ X direction) of the piezoelectric layer 10, the piezoelectric layer 20 is subjected to a tensile force. Polarization occurs in the direction (+ Z direction) so that the upper surface is positively charged.

In the above case, the piezoelectric layer 10 and the piezoelectric layer 20 have the same piezoelectric characteristics. In the above, even when clockwise is paraphrased as counterclockwise, the piezoelectric layer 10 and the piezoelectric layer 20 have the same piezoelectric characteristics. On the other hand, the piezoelectric layer 10 is polarized so that the upper surface is positively charged (for example, in the + Z direction), and the piezoelectric layer 20 is polarized so that the lower surface is positively charged (for example, in the −Z direction). If so, the piezoelectric layer 10 and the piezoelectric layer 20 have different piezoelectric characteristics.

If a piezoelectric layer 10 and a piezoelectric layer 20 are laminated so that the stretching directions of the piezoelectric layer 10 and the piezoelectric layer 20 are in the same direction to produce a piezoelectric device, a force is applied to the piezoelectric device 1. In this case, the directions of polarization in all the piezoelectric layers 10 and 20 are the same. In this case, opposite charges are generated on the facing surfaces of the adjacent piezoelectric layer 10 and the piezoelectric layer 20. Therefore, if the opposing surfaces of the adjacent piezoelectric layer 10 and the piezoelectric layer 20 are not electrically insulated, the charges cancel each other out.

On the other hand, in the piezoelectric device 1 according to the present embodiment, the piezoelectric layers 10 and the piezoelectric layers 20 are alternately arranged and laminated, and the stretching direction of the piezoelectric layer 10 and the stretching direction of the piezoelectric layer 20 intersect. ing. Therefore, when a force such as a tensile force is applied to the piezoelectric device 1, the direction of the force applied to the piezoelectric layer 10 with respect to the stretching direction of the piezoelectric layer 10 and the direction of the force applied to the piezoelectric layer 20 with respect to the stretching direction of the piezoelectric layer 20 are different. ,different. Therefore, although the piezoelectric layer 10 and the piezoelectric layer 20 have the same piezoelectric characteristics, the piezoelectric layer 10 and the piezoelectric layer 20 are polarized in opposite directions. Therefore, the same electric charge is generated on the facing surfaces of the adjacent piezoelectric layer 10 and the piezoelectric layer 20.

Therefore, in the piezoelectric device 1 according to the present embodiment, although a plurality of piezoelectric layers 10 and 20 having the same piezoelectric characteristics are laminated, the opposing surfaces of the adjacent piezoelectric layers 10 and 20 are electrically connected. Even if it is not specifically insulated, a voltage corresponding to the force can be generated when a force is applied. Then, the voltage thus generated can be taken out from the conductive layer 30 interposed between the piezoelectric layer 10 and the piezoelectric layer 20.

The outline of the manufacturing method of the piezoelectric device 1 will be described with reference to FIGS. 3A to 3E and FIGS. 4A to 4E.

In manufacturing the piezoelectric device 1, a first film material 101 and a second film material 201 are prepared. Each of the first film material 101 and the second film material 201 includes a stretched resin film 400. A conductive film 301 in which at least one of the first film material 101 and the second film material 201 overlaps the stretched resin film 400 is further provided. The stretched resin film 400 (401) of the first film material 101 and the stretched resin film 400 (402) of the second film material 201 have the same piezoelectric characteristics. That is, the direction of the tensile force with respect to the stretching direction when a tensile force is applied to the stretched resin film 401 and the stretched resin film 402, and the direction of polarization of the stretched resin film 401 and the stretched resin film 402 generated by this tensile force. The relationship is the same. The first film material 101 and the second film material 201 intersect with each other in the stretching direction of the stretched resin film 401 of the first film material 101 and the stretching direction of the stretched resin film 402 of the second film material 201. Knit and fold as you like.

Therefore, the piezoelectric device 1 can be manufactured from the first film material 101 and the second film material 201 having the stretched resin film 400 having the same piezoelectric characteristics.

Thereby, for example, the piezoelectric layer 10 can be produced from the stretched resin film 401, the piezoelectric layer 20 can be produced from the stretched resin film 402, and the conductive layer 30 can be produced from the conductive film 301.

The piezoelectric layer 10 included in the first group and the piezoelectric layer 20 included in the second group in the above description are convenient names for distinguishing between the two, and the first group in the above description. The names of the piezoelectric layer 10 included in the above and the piezoelectric layer 20 included in the second group may be interchanged. Similarly, the first film material 101 and the second film material 201 in the above description are convenient names for distinguishing between the two, and the first film material 101 and the second film in the above description are used. The name of the material 201 may be replaced.

Further, in the present embodiment, either one of the first film material 101 and the second film material 201 may include the conductive film 301. In this case, for example, the first film material 101 may include a conductive film 301 that overlaps on both sides of the stretched resin film 401. The first film material 101 and the second film material 201 may both include the conductive film 301.

The piezoelectric device 1 includes, for example, a traffic field such as a traffic sensor and a tire pressure sensor, a security field such as intrusion detection and theft warning, an acoustic / ultrasonic field such as an acoustic pickup, a fish finder, and a sonar, and medical treatment such as supersonic diagnosis. It can be applied to various fields such as fields and floor power generation fields.

Hereinafter, embodiments will be described more specifically.

[First Embodiment]
In the following description, the direction in which the piezoelectric layer 10 and the piezoelectric layer 20 are laminated is referred to as the vertical direction, one side of the vertical direction is referred to as an upper side, and the opposite side of the upper side is referred to as a lower side. The vertical direction, the upper direction, and the lower direction are convenient names, and these terms do not limit the orientation and orientation of the piezoelectric device 1.

As shown in FIG. 1, the piezoelectric device 1 according to the first embodiment includes a piezoelectric layer 10, a piezoelectric layer 20, and a conductive layer 30. The piezoelectric layer 10 and the piezoelectric layer 20 are alternately arranged and laminated. A conductive layer 30 is interposed between the adjacent piezoelectric layers 10 and the piezoelectric layer 20. That is, the piezoelectric layer 10, the conductive layer 30, the piezoelectric layer 20, and the conductive layer 30 are repeatedly arranged and laminated in this order. The aggregate of the piezoelectric layer 10, the piezoelectric layer 20, and the conductive layer 30 is hereinafter referred to as a laminated body 5.

The laminate 5 may or may not further include a conductive layer 30 that overlaps the upper surface of the uppermost layer of the piezoelectric layer 10 and the piezoelectric layer 20. The laminate 5 may or may not include a conductive layer 30 that overlaps the lowermost layer of the piezoelectric layer 10 and the piezoelectric layer 20.

The piezoelectric layer 10 and the piezoelectric layer 20 are stretched resin films. The stretching direction of the piezoelectric layer 10 (D1 direction shown in FIG. 2) is orthogonal to the vertical direction, and the stretching direction of the piezoelectric layer 20 (D2 direction shown in FIG. 2) is orthogonal to the vertical direction.

The stretched resin film has piezoelectricity.

The stretching directions (D1 direction) of the piezoelectric layer 10 are all the same direction.

The stretching direction (D2 direction) of the piezoelectric layer 20 is also the same direction.

The same direction is not limited to exactly the same direction. Even if the stretching directions are slightly different, in view of common general knowledge, it is sufficient as long as it can be equated with the case where the directions are exactly the same, that is, a state in which the desired action of the present embodiment can be obtained. That is, the same direction includes substantially the same direction.

Regardless of which two piezoelectric layers 10 included in the first group are selected, the angle formed by the two piezoelectric layers 10 in the stretching direction is preferably 30 degrees or less. If the angle formed by the stretching direction is 30 degrees or less, it can be said that the stretching directions are the same. The angle formed in the stretching direction is more preferably 20 degrees or less, further preferably 10 degrees or less, and particularly preferably 0 degrees. In this case, the piezoelectric device 1 can generate a higher voltage when a force is applied.

Regardless of which two piezoelectric layers 20 included in the second group are selected, the angle formed by the two piezoelectric layers 20 in the stretching direction is preferably 30 degrees or less. If the angle formed by the stretching direction is 30 degrees or less, it can be said that the stretching directions are the same. The angle formed in the stretching direction is more preferably 20 degrees or less, further preferably 10 degrees or less, and particularly preferably 0 degrees. In this case, the piezoelectric device 1 can generate a particularly high voltage when a force is applied.

The stretching direction of the piezoelectric layer 10 and the stretching direction of the piezoelectric layer 20 intersect. That is, the stretching direction of the piezoelectric layer 10 and the stretching direction of the piezoelectric layer 20 are not the same direction.

The angle formed by the stretching direction of any piezoelectric layer 10 selected from the piezoelectric layers 10 included in the first group and the stretching direction of any piezoelectric layer 20 selected from the piezoelectric layers 20 included in the second group. It is preferably 75 degrees or more and 105 degrees or less. In this case, the piezoelectric device 1 can generate a particularly high voltage when a force is applied. The angle formed by the stretching direction of the piezoelectric layer 10 and the stretching direction of the piezoelectric layer 20 is more preferably 80 degrees or more and 100 degrees or less, and further preferably 85 degrees or more and 95 degrees or less.

The piezoelectric layer 10 and the piezoelectric layer 20 preferably contain the same type of spiral polymer. In other words, it is preferable that the piezoelectric layer 10 contains a spiral polymer, the piezoelectric layer 20 also contains a spiral polymer, and the spiral polymer in the piezoelectric layer 10 and the spiral polymer in the piezoelectric layer 20 are of the same type. In other words, the piezoelectric layer 10 and the piezoelectric layer 20 are preferably stretched resin films containing the same type of spiral polymer. In this case, the piezoelectric layer 10 and the piezoelectric layer 20 can have particularly high piezoelectric characteristics, and the piezoelectric device 1 can generate a higher voltage when a force is applied. The spiral polymer in the piezoelectric layer 10 is oriented in the stretching direction of the piezoelectric layer 10, and the spiral polymer in the piezoelectric layer 20 is oriented in the stretching direction of the piezoelectric layer 20. That is, the direction in which the spiral polymer is oriented is the stretching direction.

The helical polymer has a molecular chain having a helical structure. Spiral polymers include, for example, polymers or copolymers of chiral molecules. The same species means that the molecular structure is the same, including the optical activity.

The spiral polymer is preferably L-form polylactic acid or D-form polylactic acid. That is, it is preferable that both the piezoelectric layer 10 and the piezoelectric layer 20 contain L-form polylactic acid or D-form polylactic acid. When the spiral polymer is L-form polylactic acid or D-form polylactic acid, the piezoelectric device 1 can generate a particularly high voltage when a force is applied. Further, since both L-form polylactic acid and D-form polylactic acid are biodegradable polymers, it is expected to reduce the environmental load. That is, the piezoelectric device can be made into an environment-friendly device.

The thickness of the piezoelectric layer 10 and the piezoelectric layer 20 is, for example, 3 μm or more and 200 μm or less.

The conductive layer 30 is electrically connected to the piezoelectric layer 10 and the piezoelectric layer 20 in contact with the conductive layer 30. The conductive layer 30 has conductivity. The conductive layer 30 is at least one metal selected from the group consisting of, for example, indium, tin, zinc, gallium, antimony, titanium, silicon, zirconium, magnesium, aluminum, gold, silver, copper, palladium, and tungsten, or at least one metal. It is made from a kind of metal oxide. The thickness of the conductive layer 30 is, for example, 10 nm or more and 5 μm or less.

In the first embodiment, the conductive layer 30 has a main body portion 30a and a terminal portion 30b. The main body 30a has dimensions smaller than those of the piezoelectric layer 10 and the piezoelectric layer 20 when viewed from above. The main body 30a does not contact the peripheral edge of the piezoelectric layer 10 that overlaps the conductive layer 30, and does not contact the peripheral edge of the piezoelectric layer 20 that overlaps the conductive layer 30. The terminal portion 30b protrudes from the edge of the main body portion 30a and is in contact with a part of the peripheral edge portion of the piezoelectric layer 10 and a part of the peripheral edge portion of the piezoelectric layer 20. The conductive layer 30 has the same dimensions as the piezoelectric layer 10 and the piezoelectric layer 20 when viewed from above, and is in contact with the entire piezoelectric layer 10 overlapping the conductive layer 30 and the entire piezoelectric layer 20 overlapping the conductive layer 30. You may. The conductive layer 30 may have an appropriate shape and dimensions other than these.

The conductive layer 30 has a first conductive layer 31 having a piezoelectric layer 10 on the lower side and a piezoelectric layer 20 on the upper side, and a second conductive layer on which the piezoelectric layer 10 is on the upper side and the piezoelectric layer 20 is on the lower side. Layer 32 and the like are included.

The voltage generated by the piezoelectric device 1 is taken out from the conductive layer 30. The piezoelectric device 1 may include an external electrode that is electrically connected to the conductive layer 30. The external electrode is provided, for example, along the outer surface of the laminated body 5. The external electrode includes an electrode that is electrically connected to the first conductive layer 31 and an electrode that is electrically connected to the second conductive layer 32. When the piezoelectric device 1 includes an external electrode, the voltage generated by the piezoelectric device 1 can be extracted from the external power to the outside. When the conductive layer 30 has the terminal portion 30b, the external electrode and the conductive layer 30 can be easily electrically connected by providing the external electrode so as to be in contact with the terminal portion 30b.

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

In the first embodiment, the opposing surfaces of the piezoelectric layer 10 and the piezoelectric layer 20 adjacent to each other via the conductive layer 30 are electrically connected by the conductive layer 30. That is, the opposing surfaces of the piezoelectric layer 10 and the piezoelectric layer 20 are not electrically insulated from each other, and the piezoelectric layer 10 and the piezoelectric layer 20 are electrically sandwiched between the piezoelectric layer 10 and the piezoelectric layer 20. No insulating layer is placed to insulate. In addition to the conductive layer 30, a layer that does not electrically insulate between the piezoelectric layer 10 and the piezoelectric layer 20 may be interposed between the piezoelectric layer 10 and the piezoelectric layer 20. For example, an adhesive layer that adheres the outer edge portion of the piezoelectric layer 10 and the outer edge portion of the piezoelectric layer 20 may be interposed between the piezoelectric layer 10 and the piezoelectric layer 20. An adhesive layer that adheres the piezoelectric layer 10 and the conductive layer 30 and does not electrically insulate the two may be interposed. An adhesive layer that adheres the piezoelectric layer 20 and the conductive layer 30 and does not electrically insulate the two may be interposed.

Further, the number of the piezoelectric layers 10 and the number of the piezoelectric layers 20 are not limited to the numbers shown in FIG. 1, and the numbers of the piezoelectric layers 10 and the piezoelectric layers 20 may be appropriately set according to the application, the required amount of power generation, and the like. Good.

The method for manufacturing the piezoelectric device 1 according to the first embodiment will be described with reference to FIGS. 3A to 3E and FIGS. 4A to 4E.

The first film material 101 and the second film material 201 are prepared. The first film material 101 includes a stretched resin film 401. The second film material 201 includes a stretched resin film 402. The first film material 101 further includes a conductive film 301 that overlaps the stretched resin film 401. On the other hand, the second film material 201 does not have a conductive film. That is, the second film material 201 is composed of only the stretched resin film 402.

The stretched resin film 401 is a material for producing the piezoelectric layer 10, and has the same structure as the piezoelectric layer 10 except for its shape. The stretched resin film 402 is a material for producing the piezoelectric layer 20, and has the same structure as the piezoelectric layer 20 except for its shape. Therefore, the stretched resin film 401 and the stretched resin film 402 have the same piezoelectric characteristics. Further, the stretched resin film 401 and the stretched resin film 402 preferably contain the same type of spiral polymer. Further, the spiral polymer is preferably L-form polylactic acid or D-form polylactic acid.

The stretched resin film 401 has a strip shape having a predetermined length, and the stretching direction of the stretched resin film 401 coincides with the length direction of the stretched resin film 401. The stretched resin film 402 also has a strip shape having a predetermined length, and the stretching direction of the stretched resin film 402 coincides with the length direction of the stretched resin film 402. It is preferable that the width dimension of the stretched resin film 401 and the width dimension of the stretched resin film 402 are the same.

The conductive film 301 is a material for producing the conductive layer 30. Therefore, the material of the conductive film 301 is the same as that of the conductive layer 30. The conductive film 301 can be formed by depositing a conductive material on, for example, a stretched resin film 401. The conductive film 301 may be formed by, for example, applying an adhesive and then stacking conductive sheets such as metal foils.

In the first embodiment, the thickness of the conductive film 301 corresponds to the thickness of the conductive layer 30.

The first film material 101 includes a conductive film 301 that overlaps one surface of the stretched resin film 401 (hereinafter referred to as an upper surface) and a surface of the stretched resin film 401 opposite to the upper surface (hereinafter referred to as a lower surface). .. The conductive film 301 on the upper surface of the stretched resin film 401 is divided into a plurality of separation films. The separation membranes are arranged in the longitudinal direction of the stretched resin film 401 at intervals. The separation membrane includes a first separation membrane 311 corresponding to the first conductive layer 31 and a second separation membrane 312 corresponding to the second conductive layer 32. The first separation membrane 311 and the second separation membrane 312 are arranged alternately. Similarly, the conductive film 301 on the lower surface of the stretched resin film 401 is also divided into a plurality of separation films, and this separation film also includes the first separation film 311 and the second separation film 312. Each separation membrane has one protruding portion 311b (312b) corresponding to the terminal portion 30b. The protruding portion 311b (312b) protrudes in the direction along the longitudinal direction of the stretched resin film 401. Further, the protruding portion 311b on the upper surface separating film of the stretched resin film 401 and the protruding portion 312b on the lower surface separating film of the stretched resin film 401 project in opposite directions with respect to the longitudinal direction. The first separation membrane 311 on the upper surface of the stretched resin film 401 and the second separation membrane 312 on the lower surface of the stretched resin film 401 form a pair, respectively, and the first separation membrane 311 and the second separation membrane 312 in each pair are They face each other via the stretched resin film 401. Similarly, the second separation membrane 312 on the upper surface of the stretched resin film 401 and the first separation membrane 311 on the lower surface of the stretched resin film 401 form a pair, respectively, and the second separation membrane 312 and the first separation membrane in each pair form a pair. The 311s face each other via the stretched resin film 401.

It is preferable to mark the conductive film 301. That is, it is preferable to provide a mark on the conductive film 301. In this case, a person engaged in the manufacture of the piezoelectric device 1 can grasp the correct positional relationship between the first film material 101 and the second film material 201 based on the mark provided on the conductive film 301. Therefore, the piezoelectric device 1 can be smoothly manufactured. For example, as shown in FIG. 11A, if the first separation membrane 311 is marked with "A" and the second separation membrane 312 is marked with "B", which have different shapes, the first separation membrane 311 and the second separation membrane 312 are provided. Can be easily identified. Further, if the conductive film 301 overlapping the upper surface of the stretched resin film 401 and the conductive film 301 overlapping the lower surface of the stretched resin film 401 are provided with marks having different shapes, the upper surface and the lower surface of the stretched resin film 401 can be easily distinguished. Can be done. Marking is performed by an appropriate method. For example, marking is performed by partially applying ink or the like to the conductive film. Marking may be performed by removing a part of the conductive film and marking the removed part as a mark.

The first film material 101 and the second film material 201 intersect with each other in the stretching direction of the stretched resin film 401 of the first film material 101 and the stretching direction of the stretched resin film 402 of the second film material 201. The piezoelectric device 1 can be manufactured by weaving and folding it so as to do so.

According to the method for manufacturing the piezoelectric device 1 according to the first embodiment, the stretched resin film 401 in the first film material 101 and the stretched resin film 402 in the second film material 201 have the same piezoelectric characteristics. A kind of film can be used. Therefore, the labor in manufacturing can be suppressed, and the cost can be reduced.

In addition, weaving folding means that one of the two materials is folded back alternately and the other is folded back in a state where a part of the two materials is overlapped with each other. It means to alternately overlap the folded parts.

In knitting and folding, for example, first, the stretching direction of the stretched resin film 401 of the first film material 101 and the stretching direction of the stretched resin film 402 of the second film material 201 intersect with each other. The end portion of the film material 101 and the end portion of the second film material 201 are overlapped with each other. Next, the first film material 101 is folded back along the long side of the second film material 201 and superposed on the second film material 201, and then the second film material 201 is placed on the length of the first film material 101. The process of folding back along the sides and stacking on the first film material 101 is repeated.

Therefore, the piezoelectric device 1 can be easily manufactured by knitting and folding the first film material 101 and the second film material 201, so that the labor in manufacturing can be omitted and the production can be performed. It can contribute to the improvement of efficiency.

Since the first film material 101 and the second film material 201 are long, for example, the stretched resin film 401 wound in a reel shape can be unwound and woven and folded according to an appropriate size. , Production efficiency can be further improved.

More specifically, in the first embodiment, the braided folding of the first film material 101 and the second film material 201 is performed, for example, as follows.

First, as shown in FIG. 4A, the first film material 101 is first stretched so that the stretched resin film 401 is crossed and the second film material 201 is stretched resin film 402. The end portion of the film material 101 and the end portion of the second film material 201 are overlapped with each other. Specifically, for example, the first film material 101 is arranged so that the upper surface of the stretched resin film 401 faces upward. At the end of the first film material 101, one first separation membrane 311 faces upward. On the first separation membrane 311 at the end of the first film material 101, the end of the second film material 201 is placed in the longitudinal direction of the first film material 101 and the longitudinal direction of the second film material 201. Overlap with and at right angles. In this case, if the conductive film 301 is marked, it is easy for a person engaged in manufacturing to correctly set the positional relationship between the first film material 101 and the second film material 201.

Next, as shown in FIG. 4B, the first film material 101 is folded back along the long side of the second film material 201 and superposed on the second film material 201. As a result, one second separation membrane 312 in the first film material 101 is superposed on the second film material 201. Next, as shown in FIG. 4C, the second film material 201 is folded back along the long side of the first film material 101 and superposed on the first film material 101. As a result, the second film material 201 is superposed on the one first separation membrane 311 in the first film material 101. In this way, the first film material 101 is folded back and then the second film material 201 is folded back repeatedly. As a result, the product as shown in FIG. 4D, which is produced by weaving and folding the first film material 101 and the second film material 201, is hereinafter referred to as an intermediate product 6.

When the first film material 101 and the second film material 201 are woven and folded in this way, the second film by folding back the first film material 101 of the stretched resin film 401 in the first film material 101. The piezoelectric layer 10 is produced from the portion overlapping the material 201. Further, the piezoelectric layer 20 is produced from the portion of the stretched resin film 402 in the second film material 201 that overlaps with the first film material 101 by folding back the second film material 201. Further, the conductive layer 30 is produced from the conductive film 301. In the first embodiment, the first conductive layer 31 is made from the first separation membrane 311 and the second conductive layer 32 is made from the second separation membrane 312. Each first conductive layer 31 is composed of one first separation membrane 311 and each second conductive layer 32 is composed of one second separation membrane 312. In this case, the stretching directions of the piezoelectric layer 10 are all the same, and the stretching directions of the piezoelectric layer 20 are also the same. Further, the stretching direction of the piezoelectric layer 10 and the stretching direction of the piezoelectric layer 20 are orthogonal to each other.

In producing the intermediate product 6, the portion where the stretched resin film and the stretched resin film directly overlap may be heat-sealed or bonded with an adhesive. The separation membrane and the stretched resin film may be heat-sealed or adhered with an adhesive that does not interfere with the electrical connection between the separation membrane and the stretched resin film.

It is also preferable to cut off the folded-back portion of the first film material 101 and the folded-back portion of the second film material 201 from the intermediate product 6. In this case, the first film material 101 can be separated into a plurality of piezoelectric layers 10, and the second film material 201 can be separated into a plurality of piezoelectric layers 20. For example, by cutting the intermediate product 6 at the position of the arrow shown in FIG. 4E, the laminated body 5 shown in FIG. 1 can be obtained. Further, in the first embodiment, the conductive layer derived from the protruding portion 311b (312b) of the separation membrane is formed on the cut surface formed by cutting the folded portion of the first film material 101 and the second film material 201. The terminal portion 30b of the above can be exposed.

An external electrode is provided on the laminated body 5 as needed. The external electrode can be manufactured by a known method such as a thermal spraying method. When the external electrode is provided on the laminated body 5, the voltage can be efficiently taken out from the piezoelectric device 1 by electrically connecting the external electrode to the terminal portion 30b.

The method of weaving is not limited to the above description. For example, first, a portion other than the end portion of the first film material 101 and the second film material 201 may be overlapped and then folded back. Further, the first film material 101 and the second film material 201 may be overlapped so as to intersect the stretching directions even if the longitudinal directions are not orthogonal to each other.

Further, the pattern of the conductive film is not limited to the above description. For example, the position of the protruding portion 311b (312b) is appropriately set according to the position of the terminal portion 30b in the piezoelectric device 1. For example, as shown as an example in FIGS. 11A to 11G, various patterns corresponding to the positions and shapes of the terminals formed from the protruding portions 311b (312b) of the conductive film 301 can be formed.

Further, the conductive film 301 does not have to be separated into a plurality of separation films. Even in that case, the conductive film can be separated into a plurality of conductive layers by cutting off the folded portion from the intermediate product.

[Second Embodiment]
In the piezoelectric device 1 according to the second embodiment, in the first embodiment, each conductive layer 30 includes a first layer 33 and a second layer 34. Further, each conductive layer 30 includes two terminal portions. Other than that, the configuration of the piezoelectric device 1 according to the second embodiment is the same as that of the piezoelectric device 1 according to the first embodiment. In the following, the same components as those in the first embodiment will be designated by the same reference numerals, and duplicate description will be omitted as appropriate.

As shown in FIGS. 5A and 5B, the first layer 33 and the second layer 34 overlap each other in the vertical direction. The first layer 33 overlaps the piezoelectric layer 10, and the second layer 34 overlaps the piezoelectric layer 20. The first layer 33 and the second layer 34 are electrically connected to each other. The first layer 33 and the second layer 34 may be in direct contact with each other. The first layer 33 and the second layer 34 may be adhered with a conductive adhesive or an adhesive that does not interfere with the electrical connection between the first layer 33 and the second layer 34. Each conductive layer 30 includes a terminal portion 33b included in the first layer 33 and a terminal portion 34b included in the second layer 34. The two terminal portions of the first conductive layer 31 project in a direction orthogonal to each other, and the two terminal portions of the second conductive layer 32 also project in a direction orthogonal to each other. Further, the two terminal portions of the first conductive layer 31 and the two terminal portions of the second conductive layer 32 project in four different directions.

The manufacturing method of the piezoelectric device 1 according to the second embodiment will be described with reference to FIGS. 6A, 6B and 7A to 7D.

The first film material 101 and the second film material 201 are prepared. The first film material 101 includes a stretched resin film 401. The second film material 201 includes a stretched resin film 402. The first film material 101 further includes a conductive film 301 that overlaps the stretched resin film 401. The second film material 201 also further includes a conductive film 302 that overlaps the stretched resin film 401.

The stretched resin film 401 and the stretched resin film 402 have the same configuration as in the case of the first embodiment.

The conductive film 301 in the first film material 101 has the same configuration as the conductive film 301 in the first embodiment, except that the thickness matches the thickness of the first layer 33.

The conductive film 302 in the second film material 201 has the same configuration as the conductive film in the first film material 101 of the first embodiment, except that the thickness matches the thickness of the second layer 34. That is, the second film material 201 includes a conductive film 302 that overlaps the upper surface of the stretched resin film 402 and the lower surface of the stretched resin film 402, respectively. The conductive film 302 on the upper surface of the stretched resin film 402 is divided into a plurality of separation films, and these separation films correspond to the first separation film 311 corresponding to the first conductive layer 31 and the second conductive layer 32. Includes a second separation membrane 312. The conductive film 302 on the lower surface of the stretched resin film 402 is also divided into a plurality of separation films, and these separation films also correspond to the first separation film 311 corresponding to the first conductive layer 31 and the second conductive layer 32. Includes a second separation membrane 312.

Also in the second embodiment, it is preferable to mark the conductive film. That is, it is preferable to provide a mark on the conductive film. In this case, as in the first embodiment, the piezoelectric device 1 can be smoothly manufactured. For example, as shown in FIG. 11A, if the first separation membrane 311 and the second separation membrane 312 are provided with marks having different shapes, the first separation membrane 311 and the second separation membrane 312 can be easily distinguished. .. Further, if the conductive film 301 overlapping the upper surface of the stretched resin film 401 and the conductive film 301 overlapping the lower surface of the stretched resin film 401 are provided with marks having different shapes, the upper surface and the lower surface of the stretched resin film 401 can be easily distinguished. Can be done. Further, if the conductive film 302 overlapping the upper surface of the stretched resin film 402 and the conductive film 302 overlapping the lower surface of the stretched resin film 402 are provided with marks having different shapes, the upper surface and the lower surface of the stretched resin film 402 can be easily distinguished. Can be done.

Also in the second embodiment, the first film material 101 and the second film material 201 are used in the stretching direction of the stretched resin film 401 of the first film material 101 and the stretched resin film 402 of the second film material 201. The piezoelectric device 1 can be manufactured by knitting and folding so that the stretching directions of the films intersect with each other.

More specifically, in the second embodiment, the first film material 101 and the second film material 201 are woven and folded, for example, as follows.

As shown in FIG. 7A, first, the stretching direction of the stretched resin film 401 of the first film material 101 and the stretching direction of the stretched resin film 402 of the second film material 201 intersect with each other. The end portion of the film material 101 and the end portion of the second film material 201 are overlapped with each other. Specifically, for example, the first film material 101 is arranged so that the upper surface of the stretched resin film 401 faces upward. At the end of the first film material 101, one first separation membrane 311 faces upward. The end portion of the second film material 201 is overlapped with the end portion of the first film material 101 in a state where the longitudinal direction of the first film material 101 and the longitudinal direction of the second film material 201 are orthogonal to each other. At this time, at the end of the second film material 201, one first separation membrane 311 faces downward. That is, the first separation film 311 of the second film material 201 is superposed on the first separation film 311 of the first film material 101. In this case, if the conductive film 301 is marked, it is easy for a person engaged in manufacturing to correctly set the positional relationship between the first film material 101 and the second film material 201.

Next, as shown in FIG. 7B, the first film material 101 is folded back along the long side of the second film material 201 and superposed on the second film material 201. As a result, one second separation membrane 312 in the first film material 101 is superposed on one second separation membrane 312 in the second film material 201. Next, as shown in FIG. 7C, the second film material 201 is folded back along the long side of the first film material 101 and superposed on the first film material 101. As a result, one first separation film 311 in the second film material 201 is superposed on one first separation film 311 in the first film material 101. In this way, the first film material 101 is folded back and then the second film material 201 is folded back repeatedly. The product as shown in FIG. 7D, which is produced by weaving and folding the first film material 101 and the second film material 201, is hereinafter referred to as intermediate product 6.

In this way, when the first film material 101 and the second film material 201 are woven and folded, the first film material 101 of the stretched resin film 401 in the first film material 101 is folded back to form the second film material 101. The piezoelectric layer 10 is produced from the portion overlapping the film material 201. Further, the piezoelectric layer 20 is produced from the portion of the stretched resin film 402 in the second film material 201 that overlaps with the first film material 101 by folding back the second film material 201. Further, the conductive layer 30 is produced from the conductive film 301. In the second embodiment, the first layer 33 is made from the first separation membrane 311 of the first film material 101, and the second layer 34 is made from the first separation membrane 311 of the second film material 201. The first conductive layer 31 is produced from the first layer 33 and the second layer 34. Further, the first layer 33 is produced from the second separation film 312 of the first film material 101, and the second layer 34 is produced from the second separation film 312 of the second film material 201, and these first layers 33 are produced. And the second layer 34 make a second conductive layer 32. That is, each first conductive layer 31 is composed of two first separation membranes 311 and each second conductive layer 32 is composed of two second separation membranes 312. In this case, the stretching directions of the piezoelectric layer 10 are all the same, and the stretching directions of the piezoelectric layer 20 are also the same. Further, the stretching direction of the piezoelectric layer 10 and the stretching direction of the piezoelectric layer 20 are orthogonal to each other.

In producing the intermediate product 6, the portion where the stretched resin film of the first film material and the stretched resin film of the second film material directly overlap may be heat-sealed or bonded with an adhesive. .. The separation membrane and the stretched resin film may be adhered with an adhesive that does not interfere with the electrical connection between the separation membrane and the stretched resin film. The overlapping separation membranes may be adhered to each other with a conductive adhesive or an adhesive that does not interfere with the electrical connection between the separation membranes.

Similar to the first embodiment, it is also preferable to cut off the folded-back portion of the first film material 101 and the folded-back portion of the second film material 201 from the intermediate product 6. In this case, the first film material 101 can be separated into a plurality of piezoelectric layers 10, and the second film material 201 can be separated into a plurality of piezoelectric layers 20. As a result, the laminated body 5 shown in FIG. 5A is obtained. Further, in the second embodiment, the terminal portion of the conductive layer derived from the protruding portion of the separation membrane can be exposed on the cut surface formed by cutting the folded portion of the first film material 101.

External electrodes are provided on the laminate as needed. The external electrode can be manufactured by a known method such as a thermal spraying method. When the external electrode is provided on the laminate, the voltage can be efficiently taken out from the piezoelectric device 1 by electrically connecting the external electrode to the terminal portion.

In the second embodiment, the stretched resin film 401 in the first film material 101 and the stretched resin film 402 in the second film material 201 can have the same configuration, and the conductive film in the first film material 101 The conductive film 302 in the 301 and the second film material 201 can have the same configuration. That is, the first film material 101 and the second film material 201 can have the same configuration. Therefore, it is not necessary to prepare different materials for the first film material 101 and the second film material 201, and the piezoelectric device 1 can be manufactured from the same film material. Therefore, the labor in manufacturing can be suppressed.

[Third Embodiment]
In the piezoelectric device 1 according to the third embodiment, as shown in FIGS. 8A and 8B, the terminal portion of the first conductive layer 31 and the terminal portion of the second conductive layer 32 project in directions orthogonal to each other. There is. Other than this, the piezoelectric device 1 according to the third embodiment includes substantially the same components as the piezoelectric device according to the first embodiment. In the following, the same components as those in the first embodiment will be described by adding the same reference numerals and omitting duplicate explanations.

The manufacturing method of the piezoelectric device 1 according to the third embodiment will be described with reference to FIGS. 9A to 9D and FIGS. 10A to 10D.

The first film material 103 and the second film material 203 are prepared. The first film material 103 includes a stretched resin film 401. The second film material 203 includes a stretched resin film 402. The first film material 103 further includes a conductive film 303 that overlaps the stretched resin film 401. The second film material 203 also further includes a conductive film 304 that overlaps the stretched resin film 402.

The stretched resin film 401 and the stretched resin film 402 have the same configuration as in the case of the first embodiment.

The first film material 103 includes a conductive film 303 that overlaps one surface of the stretched resin film 401 (hereinafter referred to as an upper surface) and a surface of the stretched resin film 402 opposite to the upper surface (hereinafter referred to as a lower surface). .. The conductive film 303 on the upper surface of the stretched resin film 401 is divided into a plurality of separation films. The separation membranes are arranged in the longitudinal direction of the stretched resin film 401 at intervals. On the upper surface of the stretched resin film 401, between adjacent separation films, there is a blank portion 501 in which no separation film is provided. That is, the separation film and the blank portion 501 are alternately arranged on the upper surface of the stretched resin film 401. The size of the blank portion 501 is slightly larger than that of the separation membrane. For example, the length of the blank portion 501 (the dimension along the longitudinal direction of the first film material 103) is the same as the width dimension of the first film material 103. The conductive film 303 on the lower surface of the stretched resin film 401 is also divided into a plurality of separation films. The lower surface of the stretched resin film 401 also has a blank portion 501 similar to the upper surface. That is, the separation film and the blank portion 501 are alternately arranged on the lower surface of the stretched resin film 401. The first separation film 331 on the upper surface of the stretched resin film 401 and the blank portion 501 on the lower surface of the stretched resin film 401 form a pair, respectively, and the blank portion 501 on the upper surface of the stretched resin film 401 and the blank portion 501 on the lower surface of the stretched resin film 401 Each of the separation films also forms a pair. The separation membrane and the blank portion 501 in each pair face each other via the stretched resin film 401. The separation membrane 331 in the first film material 103 is the first separation membrane 331 corresponding to the first conductive layer 31.

Like the first film material 103, the second film material 203 also includes a conductive film 304 that overlaps the upper surface of the stretched resin film 402 and the lower surface of the stretched resin film 402, respectively. Further, each conductive film is divided into a plurality of separation films like the first film material 103, and blank portions 502 are formed on the upper surface and the lower surface of the stretched resin film 402, respectively, like the first film material 103. is there. That is, the second film material 203 has the same structure as the first film material 103. The separation membranes in the second film material 203 are the second separation membranes 332 corresponding to the second conductive layer 32.

Also in the third embodiment, it is preferable to mark the conductive film 303 (304). That is, it is preferable to provide a mark on the conductive film 303 (304). In this case, as in the first embodiment, the piezoelectric device 1 can be smoothly manufactured.

Also in the third embodiment, the first film material 103 and the second film material 203 are used in the stretching direction of the stretched resin film 401 of the first film material 103 and the stretched resin film 402 of the second film material 203. The piezoelectric device 1 can be manufactured by knitting and folding so that the stretching directions of the films intersect with each other.

More specifically, in the third embodiment, the braided folding of the first film material 103 and the second film material 203 is performed, for example, as follows.

First, as shown in FIG. 10A, the first film material 103 is first stretched so that the stretched resin film 401 is crossed and the second film material 203 is stretched resin film 402. The end portion of the film material 103 and the end portion of the second film material 203 are overlapped with each other. Specifically, for example, the first film material 103 is arranged so that the upper surface of the stretched resin film 401 faces upward. At the end of the first film material 103, one first separation membrane 331 faces upward. The end portion of the second film material 203 is overlapped with the end portion of the first film material 103 in a state where the longitudinal direction of the first film material 103 and the longitudinal direction of the second film material 203 are orthogonal to each other. At this time, at the end portion of the second film material 203, one blank portion 502 faces downward. That is, the blank portion 502 of the second film material 203 is overlapped with the first separation film 331 of the first film material 103. In this case, if the conductive film 303 (304) is marked, it is easy for a person engaged in manufacturing to correctly set the positional relationship between the first film material 103 and the second film material 203.

Next, as shown in FIG. 10B, the first film material 103 is folded back along the long side of the second film material 203 and superposed on the second film material 203. As a result, one blank portion 501 in the first film material 103 is superposed on one second separation membrane 332 in the second film material 203. Next, as shown in FIG. 10C, the second film material 203 is folded back along the long side of the first film material 103 and superposed on the first film material 103. As a result, one blank portion 502 of the second film material 203 is superposed on the one first separation film 331 of the first film material 103. In this way, the first film material 103 is folded back and then the second film material 203 is folded back repeatedly. The product as shown in FIG. 10D, which is produced by weaving and folding the first film material 103 and the second film material 203, is hereinafter referred to as intermediate product 6.

When the first film material 103 and the second film material 203 are woven and folded in this way, the second film material by folding back the first film material 103 of the stretched resin film 401 in the first film material 103 is folded back. The piezoelectric layer 10 is produced from the portion overlapping the 203. Further, the piezoelectric layer 20 is produced from the portion of the stretched resin film 402 in the second film material 203 that overlaps with the first film material 103 by folding back the second film material 203. Further, the conductive layer 30 is produced from the conductive film 303 (304). In the third embodiment, the first conductive layer 31 is produced from the first separation membrane 331 which is the separation membrane of the first film material 103, and from the second separation membrane 332 which is the separation membrane of the second film material 203. The second conductive layer 32 is produced. That is, each first conductive layer 31 is composed of one first separation membrane 331, and each second conductive layer 32 is composed of one second separation membrane 332. In this case, the stretching directions of the piezoelectric layer 10 are all the same, and the stretching directions of the piezoelectric layer 20 are also the same. Further, the stretching direction of the piezoelectric layer 10 and the stretching direction of the piezoelectric layer 20 are orthogonal to each other.

In producing the intermediate product 6, the portion where the stretched resin film and the stretched resin film directly overlap may be heat-sealed or bonded with an adhesive. The separation membrane and the stretched resin film may be heat-sealed or adhered with an adhesive that does not interfere with the electrical connection between the separation membrane and the stretched resin film.

Similar to the first embodiment, it is also preferable to cut off the folded-back portion of the first film material 103 and the folded-back portion of the second film material 203 from the intermediate product 6. In this case, the first film material 103 can be separated into a plurality of piezoelectric layers 10, and the second film material 203 can be separated into a plurality of piezoelectric layers 20. As a result, the laminated body 5 shown in FIG. 8A is obtained. Further, in the third embodiment, the cut surface formed by cutting the folded portion of the first film material 103 and the cut surface formed by cutting the folded portion of the second film material 203 are formed. The terminal portion 30b of the conductive layer derived from the protruding portion of the separation film can be exposed.

An external electrode is provided on the laminated body 5 as needed. The external electrode can be manufactured by a known method such as a thermal spraying method. When the external electrode is provided on the laminate 5, the voltage can be efficiently taken out from the piezoelectric device 1 by electrically connecting the external electrode to the terminal portion.

In the third embodiment, the stretched resin film 401 in the first film material 103 and the stretched resin film 402 in the second film material 203 can have the same configuration, and the conductive film in the first film material 103. The conductive film 304 in the 303 and the second film material 203 can have the same configuration. That is, the first film material 103 and the second film material 203 can have the same configuration. Therefore, it is not necessary to prepare different materials for the first film material 103 and the second film material 203, and the piezoelectric device 1 can be manufactured from the same film material. Therefore, the labor in manufacturing can be suppressed. Further, in the third embodiment, each conductive layer is made of one separation membrane and is not divided into two layers as in the case of the second embodiment, so that contact resistance between layers occurs in the conductive layer. Absent.

According to the piezoelectric device of the present disclosure and the method for manufacturing the same, even if a plurality of piezoelectric layers having the same piezoelectric characteristics are laminated and the opposing surfaces of the adjacent piezoelectric layers are not electrically insulated, the force is applied. A piezoelectric device capable of generating a voltage corresponding to a force when a force is applied is obtained, which is industrially useful.

1 Piezoelectric device 10, 20 Piezoelectric layer 30 Conductive layer 101, 103 First film material 201, 203 Second film material 301, 302, 303, 304 Conductive film 400, 401, 402 Stretched resin film

Claims (9)

It has a piezoelectric layer included in the first group, a piezoelectric layer included in the second group, and a conductive layer.
The piezoelectric layer included in the first group and the piezoelectric layer included in the second group are alternately laminated, and the piezoelectric layer included in the first group adjacent to each other in the stacking direction and the piezoelectric layer. The conductive layer is interposed between the piezoelectric layer and the piezoelectric layer included in the second group.
The piezoelectric layer included in the first group and the piezoelectric layer included in the second group are stretched resin films.
The piezoelectric layer included in the first group and the piezoelectric layer included in the second group are the direction of the tensile force with respect to the stretching direction when a tensile force is applied to stretch, and the tensile force. It has a piezoelectric property that the relationship with the polarization direction of the piezoelectric layer caused by the above is the same as each other.
The stretching directions of the piezoelectric layers included in the first group are all in the same direction.
The stretching directions of the piezoelectric layers included in the second group are all in the same direction.
The stretching direction of the piezoelectric layer included in the first group intersects with the stretching direction of the piezoelectric layer included in the second group.
Piezoelectric device. The piezoelectric layer included in the first group and the piezoelectric layer included in the second group contain the same type of spiral polymer.
The piezoelectric device according to claim 1. The spiral polymer is L-form polylactic acid or D-form polylactic acid.
The piezoelectric device according to claim 2. The angle formed by any two of the piezoelectric layers selected from the piezoelectric layers included in the first group in the stretching direction is 30 degrees or less.
The angle formed by any two of the piezoelectric layers selected from the piezoelectric layers included in the second group in the stretching direction is 30 degrees or less.
The piezoelectric device according to any one of claims 1 to 3. The stretching direction of any one of the piezoelectric layers selected from the piezoelectric layers included in the first group and the stretching direction of any one of the piezoelectric layers selected from the piezoelectric layers included in the second group. The angle between the two is 75 degrees or more and 105 degrees or less.
The piezoelectric device according to any one of claims 1 to 4. Prepare the first film material and the second film material,
Each of the first film material and the second film material includes a stretched resin film.
At least one of the first film material and the second film material further includes a conductive film that overlaps the stretched resin film.
The stretched resin film of the first film material and the stretched resin film of the second film material have the direction of the tensile force with respect to the stretching direction when a tensile force is applied and the polarization caused by the tensile force. It has piezoelectric characteristics that are the same as each other in relation to the direction.
The first film material and the second film material are crossed so that the stretching direction of the stretched resin film of the first film material and the stretching direction of the stretched resin film of the second film material intersect. Including weaving and folding in
A method for manufacturing a piezoelectric device. The first film material and the second film material are both strip-shaped.
When the first film material and the second film material are woven and folded, the stretching direction of the stretched resin film of the first film material and the stretching direction of the stretched resin film of the second film material are determined. , The end of the first film material and the end of the second film material are overlapped so as to intersect with each other.
The first film material is folded back along the long side of the second film material and superposed on the second film material, and then the second film material is placed along the long side of the first film material. Repeatedly folding back and stacking on the first film material,
The method for manufacturing a piezoelectric device according to claim 6. Including cutting off the folded-back portion of the first film material and the folded-back portion of the second film material.
The method for manufacturing a piezoelectric device according to claim 6 or 7. Including a step of marking the conductive film,
The method for manufacturing a piezoelectric device according to any one of claims 6 to 8.

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