Piezoelectric film element and method for manufacturing piezoelectric film element

Abstract

To provide a piezoelectric film element capable of remarkably improving power generation output, and to provide a method for manufacturing the piezoelectric film element at high speed and with high density.SOLUTION: The method for manufacturing the piezoelectric element includes a process for forming fine processing having irregularities on the surface of a substrate 11 on at least one side of the substrate 11, a process for forming a piezoelectric film 12 having a film thickness of 100 μm or more in parallel by an aerosol deposition method, and an annealing process for each piezoelectric film 12 formed on the substrate 11.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a piezoelectric film element and a method for manufacturing a piezoelectric film element. [Background technology]

[0002] Piezoelectric materials are processed into various piezoelectric elements for various purposes, and are widely used as functional electronic components such as actuators that operate by applying voltage to cause deformation, and conversely, sensors that detect the amount of displacement from the voltage generated by the deformation of the piezoelectric element. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-033254 Summary of the Invention [Problem to be solved by the invention]

[0004] As described in Patent Document 1, piezoelectric films used in actuators or sensors need to be thickened to achieve high power generation performance. The thickness of the piezoelectric film depends on the type and thickness of the substrate, the size of the piezoelectric film element, and other factors, but thickening the film increases the amount of power that can be extracted. However, piezoelectric films have mainly been deposited using sputtering to date, which has a slow deposition rate (maximum 1.0 μm / h), making it impractical in terms of manufacturing costs to obtain thick films. The main solutions being explored are materials development (aiming to achieve performance equivalent to PZT using lead-free materials) and investigation of deposition methods (thicker films, such as hydrothermal synthesis). The present invention has been made in view of the above problems, and its purpose is to provide a piezoelectric film element that can significantly improve power generation output, and a method for manufacturing a piezoelectric film element quickly and precisely. [Means for solving the problem]

[0005] The characteristic configuration of the method for manufacturing a piezoelectric film element according to the present invention to achieve the above object is as follows: The method includes the steps of forming a micro-fabrication having irregularities on at least one side of the substrate, depositing a plurality of piezoelectric films having a thickness of 100 μm or more by an aerosol deposition method, and annealing each of the piezoelectric films deposited on the substrate. Furthermore, the piezoelectric film element according to the present invention, which achieves the above object, has the following characteristic configuration: Substrate and a plurality of piezoelectric films formed on at least one surface of the substrate; Each of the piezoelectric films is an aerosol deposition film having a thickness of 100 μm or more; The surface of the substrate has minutely processed irregularities.

[0006] According to the above-mentioned characteristic configuration, film formation by the aerosol deposition method has a high film formation speed (approximately 5 to 50 μm / min) and low equipment costs. According to the present invention, it is possible to easily manufacture a piezoelectric film element having a so-called thick film type piezoelectric film with a film thickness of 100 μm or more. A piezoelectric film element having such a thick film type piezoelectric film can ensure a larger amount of power generation.

[0007] Furthermore, by providing the substrate with micro-fabrication that creates irregularities, the power generation capacity of the piezoelectric film element can be improved. Furthermore, while crystal defects and distortions are introduced into the piezoelectric film formed by the aerosol deposition method during the film formation process, removing these defects and distortions by annealing increases the piezoelectric constant. In other words, according to the present invention, the piezoelectric constant of the piezoelectric film is high, ensuring even greater power generation capacity.

[0008] Further characteristic configurations of the manufacturing method of the piezoelectric film element and the piezoelectric film element according to the present invention are as follows: The microfabrication is performed by forming grooves in the longitudinal or lateral direction of the substrate.

[0009] By forming the microfabrication in the longitudinal or lateral direction of the substrate, it is possible to secure an even greater amount of power generation.

[0010] Further characteristic configurations of the manufacturing method of the piezoelectric film element and the piezoelectric film element according to the present invention are as follows: The cross section of the microfabrication has at least one shape selected from the group consisting of a rectangle, a triangle, and a semicircle.

[0011] It is believed that the larger the projected area of ​​the microfabricated shape relative to the main direction of polarization, the greater the amount of power generated. Therefore, with the above-described characteristic configuration, a larger amount of power can be generated.

[0012] Further characteristic configurations of the manufacturing method of the piezoelectric film element and the piezoelectric film element according to the present invention are as follows: The depth of the micro-fabrication is less than 100 μm.

[0013] The greater the microfabrication depth, the greater the power generation capacity. However, if the depth is too great, there is a risk that the piezoelectric film will crack. Therefore, by making the microfabrication depth less than 100 μm, a greater power generation capacity can be secured. If the depth is too small, the power generation capacity improvement effect cannot be expected. Therefore, it is preferable that the microfabrication depth be greater than 5 μm.

[0014] Further characteristic configurations of the manufacturing method of the piezoelectric film element and the piezoelectric film element according to the present invention are as follows: The width of the fine processing is 10 μm or more and 120 μm or less.

[0015] The larger the width of the microfabrication, the greater the amount of power generated. Therefore, by setting the width of the microfabrication within the above range, a larger amount of power can be generated.

[0016] Further characteristic configurations of the manufacturing method of the piezoelectric film element and the piezoelectric film element according to the present invention are as follows: The distance between the finely processed portions is 10 μm or more and 100 μm or less.

[0017] The closer the spacing between the microfabrications, the higher the power generation. If the spacing between the microfabrications exceeds 100 μm, the power generation cannot be improved. Also, from the perspective of processing accuracy, the spacing between the microfabrications is preferably 10 μm or more. Therefore, by setting the spacing between the microfabrications within the above range, more power generation can be ensured.

[0018] The manufacturing method of the piezoelectric film element and further characteristic configurations of the piezoelectric film element according to the present invention are each of the piezoelectric films is made of potassium sodium niobate.

[0019] Lead zirconate titanate (Pb(Zr,Ti)O3: PZT), which is widely used as a material for piezoelectric films, has a very high piezoelectric constant, which is one of the factors affecting the power generation of piezoelectric films. However, it is being strictly regulated because it contains lead, a substance harmful to the environment and the human body, at a high concentration. In contrast, potassium sodium niobate (K 1-x Na x NbO3, 0 < x < 1: KNN) is a lead-free piezoelectric material. According to the manufacturing method of the present invention, a piezoelectric film element with a low environmental load can be obtained.

[0020] A further characteristic configuration of the manufacturing method of the piezoelectric film element according to the present invention is that it further includes a step of poling each of the annealed piezoelectric films.

[0021] When the piezoelectric film formed by the aerosol deposition method is poled by applying an electric field to align the polarization directions in one direction, the piezoelectric constant increases. That is, according to the manufacturing method of the present invention, a piezoelectric film element with a high piezoelectric constant of the piezoelectric film can be manufactured, thereby ensuring even more power generation.

[0022] A further characteristic configuration of the manufacturing method of the piezoelectric film element according to the present invention is in the annealing treatment, each of the piezoelectric films is heated to 600°C to 800°C.

[0023] By performing the annealing treatment under the above conditions, a piezoelectric film exhibiting a high piezoelectric constant can be obtained.

[0024] Further characteristic features of the manufacturing method of the piezoelectric film element according to the present invention are as follows: The poling treatment involves applying a voltage of 40 kV / cm to 50 kV / cm to each of the piezoelectric films at 0° C. to 150° C. for 10 minutes to 30 minutes.

[0025] By carrying out the poling treatment under the above conditions, a piezoelectric film exhibiting a high piezoelectric constant can be obtained.

[0026] The characteristic configuration of the piezoelectric film element according to the present invention is as follows: The piezoelectric constant d of each of the piezoelectric films 33 is less than 100 pC / N.

[0027] Aerosol-deposited films have a piezoelectric constant d 33 When the piezoelectric material is KNN, the piezoelectric constant d of the sputtered film tends to be low. 33 is about 110 pC / N, while the piezoelectric constant d 33 is less than 100 pC / N.

[0028] When an aerosol deposition film with a low piezoelectric constant is used, the amount of power generated by the piezoelectric film element is usually low. However, as mentioned above, aerosol deposition films are easily made thick. Therefore, by increasing the thickness of the aerosol deposition film, the piezoelectric film element according to the present invention can ensure an amount of power generation equal to or higher than that of a sputtering film.

[0029] Further characteristic configurations of the manufacturing method of the piezoelectric film element and the piezoelectric film element according to the present invention are as follows: The microfabrication and the piezoelectric film are formed in multiple layers on both sides of the substrate.

[0030] According to the above characteristic configuration, the area of ​​the substrate can be effectively utilized to provide more piezoelectric films, thereby increasing the amount of power generated by the entire piezoelectric film element. [Brief explanation of the drawings]

[0031] [Figure 1] 1 is a plan view showing a piezoelectric film element according to the present invention. [Figure 2] 1 is a cross-sectional view showing a piezoelectric film element according to the present invention. [Figure 3] 1 is a structural example for mounting a piezoelectric film element according to the present invention. [Figure 4] FIG. 10 is an enlarged cross-sectional view of a piezoelectric film element according to the present invention, in which rectangular microfabrication is performed on the substrate. [Figure 5] FIG. 10 is an enlarged cross-sectional view of a piezoelectric film element according to the present invention, in which triangular microfabrication is performed on the substrate. [Figure 6] FIG. 10 is an enlarged cross-sectional view of a piezoelectric film element according to the present invention, in which semicircular microfabrication is performed on the substrate. [Figure 7] 10 is a graph showing the relationship between the width and depth of the microstructure and the amount of power generation. [Figure 8] 10 is a graph showing the relationship between the spacing of the microstructures and the amount of power generation. [Figure 9] 10 is a graph showing the relationship between the width of the fine structure, the direction in which the fine structure is formed, and the amount of power generation. DETAILED DESCRIPTION OF THE INVENTION

[0032] A piezoelectric film element and a manufacturing method thereof according to an embodiment of the present invention will be described below with reference to the drawings.

[0033] <Piezoelectric film element> As shown in FIGS. 1 and 2, a piezoelectric film element 10 according to one embodiment of the present invention includes a substrate 11 on which microfabrication 13 has been performed, and a piezoelectric film 12 formed on the substrate 11.

[0034] In this embodiment, the substrate 11 is preferably made of Ti and has a thickness of 0.1 mm or more and 2 mm or less. However, the present invention is not limited to this, and substrates made of metals other than Ti, such as stainless steel, or substrates with thicknesses outside the above range can also be used. In this embodiment, the substrate 11 is rectangular in plan view, and micro-fabrications 13 with concave and convex portions are formed on each of both surfaces of the substrate 11 in parallel with their long sides facing each other. A plurality of piezoelectric films 12 each having a rectangular shape in plan view are disposed on the micro-fabrications 13. However, the substrate 11 and the piezoelectric films 12 may have other shapes, and the micro-fabrications 13 and the piezoelectric films 12 may be provided on one surface of the substrate 11.

[0035] As shown in Figures 4, 5, and 6, the micro-fabrications 13 are formed in the shape of rectangular, triangular, and semicircular grooves in a cross section perpendicular to the longitudinal direction of one piezoelectric film 12 formed on a substrate 11. In this embodiment, the micro-fabrications 13 are formed in a single shape, but this is not limited thereto. The micro-fabrications 13 may be formed in a plurality of shapes selected from rectangular, triangular, and semicircular. Furthermore, the micro-fabrications 13 may be formed in the longitudinal direction so that the long sides of the substrate 11 face each other, or in the lateral direction so that the short sides of the substrate 11 face each other. Furthermore, the micro-fabrications 13 may extend linearly or in a dotted line in the longitudinal or lateral direction of the substrate 11.

[0036] Furthermore, the greater the groove width and depth of the micro-processing 13, the greater the amount of power generation, and the narrower the interval between the micro-processings 13. The micro-processing 13 can be formed by forming grooves from the top or bottom surface of the substrate 11 toward the center of the substrate 11 using methods such as NC processing, pressing, laser, and etching. The width of the micro-fabrication 13 is preferably 10 μm or more and 120 μm or less, more preferably 15 μm or more and 110 μm or less, and even more preferably 20 μm or more and 100 μm or less. In addition, the depth of the microfabrication 13 is preferably less than 100 μm, more preferably less than 90 μm, and even more preferably less than 80 μm. If the depth is too small, a sufficient power generation improvement effect cannot be expected. Therefore, the depth of the microfabrication is preferably greater than 1 μm, more preferably greater than 3 μm, even more preferably greater than 5 μm, and particularly preferably greater than 10 μm. Furthermore, the interval between the microfabrications 13 is preferably 10 μm or more and 100 μm or less, more preferably 20 μm or more and 90 μm or less, and even more preferably 30 μm or more and 80 μm or less. In this specification, the "interval between the microfabrications 13" refers to the distance between the centers of the microfabrications 13.

[0037] The piezoelectric film 12 is an aerosol deposition film with a film thickness of 10 μm or more, which is formed on the substrate 11 by the aerosol deposition (AD) method using a piezoelectric material. The film thickness of the piezoelectric film 12 can be set to any value within the range (~1 mm) that can be formed by the aerosol deposition method. For example, it can be 10 μm, 30 μm, 40 μm, or 100 μm.

[0038] In this embodiment, the piezoelectric film 12 is formed using potassium sodium niobate (K 1-x Na x NbO3, 0 < x < 1: KNN). However, the present invention is not limited to this, and any material that can form a piezoelectric film 12 with a film thickness of 10 μm or more by the aerosol deposition method can be used. For example, oxide materials having piezoelectric properties such as barium titanate (BaTiO3) and lithium niobate (LiNbO3) can be used. In addition, transition metals such as Cu, Ni, Co, Mn, and Fe may be added.

[0039] The piezoelectric film 12 formed by the aerosol deposition method tends to have a lower piezoelectric constant than the piezoelectric film formed by the sputtering method. When the piezoelectric material is KNN, the piezoelectric constant d 33 of the piezoelectric film 12 formed by the sputtering method is about 110 pC / N, whereas the piezoelectric constant d 33Although it varies depending on the film formation conditions, it is basically less than 100 pC / N. That is, in this embodiment, the piezoelectric film 12 has a piezoelectric constant d 33 is less than 100 pC / N.

[0040] 1, the piezoelectric film element 10 may further include a lower electrode formed on the surface of the piezoelectric film 12 facing the substrate 11, and an upper electrode formed on the surface of the piezoelectric film 12 opposite the substrate 11. The lower electrode and the upper electrode may be made of any conductive material, such as a metal (such as a Pt / Ti laminate) or a metal oxide. In this embodiment, where the substrate 11 is made of Ti, the piezoelectric film element 10 further includes an insulating layer provided between the substrate 11 and the lower electrode.

[0041] <Manufacturing method of piezoelectric film element> Next, a method for manufacturing the above-mentioned piezoelectric film element 10 will be described. First, a micro-fabrication 13 with concaves and convexes is formed by laser processing from the top and bottom surfaces of a Ti substrate 11 toward the center of the substrate 11. Next, a piezoelectric film 12 with a thickness of 10 μm or more is formed on the micro-fabrication 13 formed on the substrate 11 by aerosol deposition. In film formation by aerosol deposition, a KNN powder having the same composition as the desired piezoelectric film 12 is used as the raw material, and an aerosol in which the powder raw material is dispersed in a carrier gas is sprayed onto the substrate 11. In this way, a piezoelectric film 12 made of KNN is formed on the substrate 11. The thickness of the piezoelectric film 12 can be controlled, for example, by adjusting the film formation time.

[0042] Next, the piezoelectric film 12 formed on the substrate 11 is subjected to an annealing treatment. In the annealing treatment, the piezoelectric film 12 is heated at a predetermined temperature for a predetermined time. This removes crystal defects and distortions introduced during the film formation process of the piezoelectric film 12, and increases the piezoelectric constant of the piezoelectric film 12. The annealing temperature is preferably 600°C to 800°C, and more preferably 650°C to 750°C. The holding time for the annealing treatment is preferably 10 minutes to 120 minutes, and can be, for example, 30 minutes or 60 minutes.

[0043] Although not necessarily required, the annealed piezoelectric film 12 may be further subjected to a poling treatment. In the poling treatment, a predetermined voltage is applied to the piezoelectric film 12 at a predetermined temperature for a predetermined time. This aligns the polarization direction in one direction and increases the piezoelectric constant of the piezoelectric film 12. The poling temperature is preferably 0°C to 150°C, and can be, for example, 140°C or 150°C. The poling voltage is preferably 40 kV / cm to 50 kV / cm, and can be, for example, 40 kV / cm, 45 kV / cm, or 50 kV / cm. The poling time is preferably 10 minutes to 30 minutes, and can be, for example, 10 minutes or 20 minutes.

[0044] <Effects of the embodiment> The piezoelectric film element 10 of the present invention employs a piezoelectric film 12 formed by aerosol deposition, which has a lower piezoelectric constant than a piezoelectric film formed by sputtering, resulting in a corresponding decrease in the amount of power generated. However, the piezoelectric film 12 formed by aerosol deposition can be formed at a high speed (approximately 5 to 50 μm / min) and can easily be formed to a thickness of 10 μm or more. Therefore, the decrease in power generation due to the low piezoelectric constant can be offset by the increase in power generation due to the thicker piezoelectric film 12. In other words, with the piezoelectric film element 10 of the present invention, by increasing the thickness of the piezoelectric film 12, it is possible to ensure a power generation amount equal to or higher than that of a piezoelectric film formed by sputtering.

[0045] For example, the amount of power generated by each piezoelectric film of the piezoelectric film element can be calculated using the following formulas 1 and 2. V∝d×t×X / A (Formula 1) In Equation 1, V is the electromotive force of the piezoelectric film, d is the piezoelectric constant of the piezoelectric film, t is the film thickness of the piezoelectric film, X is the stress applied to the piezoelectric film, and A is the cross-sectional area of ​​the piezoelectric film. P=V2 / 2R (formula 2) In Equation 2, P is the amount of power generated, and R is the resistance value of the load resistor connected to the piezoelectric film element.

[0046] As shown in Equation 1, both the piezoelectric constant d and film thickness t are proportional to the electromotive force V. Therefore, for example, in the case of a piezoelectric film of the same thickness produced by aerosol deposition, which has a piezoelectric constant one-third that of a piezoelectric film produced by sputtering, the power generation amount P calculated based on Equation 2 is one-ninth that of a piezoelectric film produced by sputtering. Even so, if the film thickness t of the piezoelectric film produced by aerosol deposition is three times or more times larger, the power generation amount P will be greater than that of a piezoelectric film produced by sputtering. [Example]

[0047] The piezoelectric film element and the method for manufacturing the same according to the present invention will be specifically described below with reference to examples.

[0048] Example 1: Evaluation of power generation capacity of piezoelectric film element As shown in Figure 3, we assumed that the piezoelectric film element was attached to a rotating shaft 16 on the inner circumference of a vehicle tire using a substrate fixing device 15 as a power generation device, and that the rotation of the tire caused the oscillator 14 to fluctuate, generating electricity which was then supplied to other devices (such as a tire pressure sensor), and evaluated the power generation capacity of the piezoelectric film element.

[0049] (Production Example 1) A Ti substrate with dimensions of 40 mm short side length, 50 mm long side length, and 0.3 mm thick was prepared. Multiple rectangular micro-fabrications were etched onto this substrate with their long sides facing each other. In this manufacturing example, the micro-fabrications were groove-like extending along the length of the substrate. The micro-fabrications were rectangular, 100 μm wide and 50 μm deep, with 17 micro-fabrications per 2 mm short side of the KNN piezoelectric film. The spacing between micro-fabrications was 18.75 μm. Next, KNN raw material powder with an average particle size of 1 μm was prepared. This raw material powder was then applied to both sides of the substrate by aerosol deposition to form KNN piezoelectric films with dimensions of 2 mm short side length, 15 mm long side length, and 100 μm thick. The surface with the upper electrode formed on it was designated the front side, with 15 films deposited on the front side and 15 on the back side. The film deposition conditions were as follows: The 15 piezoelectric films on each surface of the substrate were arranged in parallel along the short side of the substrate so that the long side of each piezoelectric film was aligned with the long side of the substrate and the center of each piezoelectric film in the long side was located in the center of the long side of the substrate (see Figures 1 and 3). Electrodes made of a Pt / Ti laminate were formed by aerosol deposition on the entire surface of each piezoelectric film facing the substrate and on the surface opposite the substrate, and the electrode thickness was 0.1 μm. Deposition chamber vacuum degree: 650Pa Carrier gas: Air Gas flow rate: 90L / min Nozzle scan speed: 4mm / sec

[0050] The piezoelectric film of the piezoelectric film element was subjected to an annealing treatment in an air atmosphere at a heating temperature of 700°C for 60 minutes, followed by a poling treatment in which a voltage of 40 kv / cm was applied at 140°C for 20 minutes.

[0051] (Production Example 2) The piezoelectric film element was manufactured in the same manner as in Manufacturing Example 1, except that the microfabrication was in a triangular shape with a width of 109.7 μm and a depth of 95 μm, and 16 microfabrications were performed on the KNN piezoelectric film with a short side length of 2 mm. The spacing between the microfabrications was 16.32 μm.

[0052] (Production Example 3) The piezoelectric film element was manufactured in the same manner as in Manufacturing Example 1, except that the microfabrication was performed in a semicircular shape (width 119 μm, depth 59.5 μm) with a radius of 59.5 μm in the cross section perpendicular to the longitudinal direction of the substrate, and 15 microfabrications were performed on the KNN piezoelectric film with a short side length of 2 mm. The spacing between the microfabrications was 15.35 μm.

[0053] (Comparative Example) A KNN piezoelectric film was formed by aerosol deposition on each side of a substrate that had not been subjected to microfabrication. Otherwise, a piezoelectric film element was manufactured in the same manner as in Manufacturing Example 1.

[0054] The amount of power generated by each piezoelectric film for each sample was calculated based on the above formulas 1 and 2. Stress X was determined by assuming that the tire deformation due to contact with the ground was 1.42 mm, and was taken as the maximum stress (stress below the fracture limit of the piezoelectric film) when the center of the long side of the substrate was displaced by 1.42 mm. The total amount of power generated by the 30 piezoelectric films was calculated as the amount of power generated by the piezoelectric film element. The results are shown in Table 1.

[0055] [Table 1]

[0056] Energy harvesting power generation devices are generally required to generate approximately 1 mW of power. Table 1 shows that the comparative example without microfabrication generated 0.47 mW, well below 1 mW, while Manufacturing Examples 1 to 3, which were microfabricated, all achieved power generation levels well above 1 mW. It can also be seen that Manufacturing Example 3, in which the width of the microfabrication was large and the spacing between the microfabrications was narrow, had the greatest improvement in power generation.

[0057] Example 2: Evaluation of the relationship between the width and depth of microfabrication and the spacing between microfabrications Next, the relationship between the width and depth of the micro-fabrication, the spacing between the micro-fabrications, and the amount of power generation was investigated. The results are shown in Figures 7 to 9.

[0058] Figure 7 shows the effect on the amount of power generated when the spacing between micro-fabrications is fixed at 60 μm and the width and depth of the micro-fabrication are changed. As is clear from Figure 7, the amount of power generated improves as the width and depth of the micro-fabrication increase.

[0059] Figure 8 shows the effect on the amount of power generated when the width and depth of the micro-fabrication are fixed and the spacing between the micro-fabrications is changed. As is clear from Figure 8, the amount of power generated decreases as the spacing between the micro-fabrications increases, and increases as the spacing decreases.

[0060] Figure 9 shows the effect on power generation when the width is changed while the depth and spacing of the microfabrication are fixed. A comparison was made between a case where the microfabrication was formed in the longitudinal direction, with the long sides of the substrate facing each other, and a case where the microfabrication was formed in the lateral direction, with the short sides of the substrate facing each other (Type B). As is clear from Figure 9, the power generation increased as the width of the microfabrication increased, and the power generation increased whether the microfabrication was formed in the longitudinal direction or the lateral direction.

[0061] In addition, the configurations disclosed in the above embodiments can be applied in combination with configurations disclosed in other embodiments as long as no contradictions arise, and the embodiments disclosed in this specification are examples, and the embodiments of the present invention are not limited to these and can be modified as appropriate within the scope that does not deviate from the purpose of the present invention. [Explanation of symbols]

[0062] 10 Piezoelectric film element 11 Circuit Board 12 Piezoelectric film 13 Microfabrication

Claims

1. A method for manufacturing a piezoelectric film element, comprising the steps of: forming a micro-fabrication having irregularities on the surface of at least one side of a substrate; depositing parallel piezoelectric films each having a thickness of 100 μm or more by an aerosol deposition method; and annealing each of the piezoelectric films deposited on the substrate.

2. 2. The method for manufacturing a piezoelectric film element according to claim 1, wherein the microfabrication forms grooves in the longitudinal or lateral direction of the substrate.

3. 2. The method for manufacturing a piezoelectric film element according to claim 1, wherein the cross section of the micro-machined film has at least one shape selected from the group consisting of a rectangle, a triangle, and a semicircle.

4. The method for manufacturing a piezoelectric film element according to claim 1, wherein the depth of the microfabrication is less than 100 μm.

5. 2. The method for manufacturing a piezoelectric film element according to claim 1, wherein the width of the microfabrication is 10 [mu]m or more and 120 [mu]m or less.

6. 2. The method for manufacturing a piezoelectric film element according to claim 1, wherein the interval between the micro-fabrication processes is 10 [mu]m or more and 100 [mu]m or less.

7. 2. The method for manufacturing a piezoelectric film element according to claim 1, wherein each of said piezoelectric films is made of potassium sodium niobate.

8. The method for manufacturing a piezoelectric film element according to claim 1, further comprising the step of poling each of the piezoelectric films that has been annealed.

9. 2. The method for manufacturing a piezoelectric film element according to claim 1, wherein the piezoelectric films are heated to 600° C. to 800° C. in the annealing treatment.

10. 9. The method for manufacturing a piezoelectric film element according to claim 8, wherein the poling treatment involves applying a voltage of 40 kV / cm to 50 kV / cm to each of the piezoelectric films at 0° C. to 150° C. for 10 minutes to 30 minutes.

11. The method for manufacturing a piezoelectric film element according to claim 1 , wherein the microfabrication and the piezoelectric film are formed in a plurality of layers on each of both surfaces of the substrate.

12. A substrate; a plurality of piezoelectric films formed on at least one surface of the substrate; Each of the piezoelectric films is an aerosol deposition film having a thickness of 100 μm or more, The surface of the substrate is a piezoelectric film element having micro-fabrication of recesses and projections.

13. The piezoelectric film element according to claim 12, wherein the microfabrication is performed to form grooves in the longitudinal or lateral direction of the substrate.

14. The piezoelectric film element according to claim 12, wherein the cross section of the micro-machined structure has at least one of the following shapes: rectangular, triangular, and semicircular.

15. The piezoelectric film element according to claim 12, wherein the micromachining depth is less than 100 μm.

16. 13. The piezoelectric film element according to claim 12, wherein the width of the microfabrication is 10 μm or more and 120 μm or less.

17. 13. The piezoelectric film element according to claim 12, wherein the interval between the microfabrications is 10 μm or more and 100 μm or less.

18. The piezoelectric film element according to claim 12, wherein each of the piezoelectric films is made of potassium sodium niobate.

19. The piezoelectric constant d of each of the piezoelectric films ３３ The piezoelectric film element according to claim 12, wherein the resistivity is less than 100 pC / N.

20. The piezoelectric film element according to claim 12 , wherein the microfabrication and the piezoelectric film are formed in a plurality of layers on each of both surfaces of the substrate.

Images