Piezoelectric element

Abstract

To provide a piezoelectric element capable of suppressing narrowing of a detection band.SOLUTION: A piezoelectric element includes: a support 10; a vibrating portion 20 provided on the support 10, including a piezoelectric film 40 and an electrode film 50 connected to the piezoelectric film 40, and having a support region 21a supported by the support 10 and a floating region 21b connected to the support region 21a and floating from the support 10. The floating region 21b has a plurality of vibration regions 22a to 22d partitioned by slits 30, and the adjacent vibration regions 22a to 22d are connected at the support region 21a side.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a piezoelectric element having a vibrating portion. [Background technology]

[0002] Piezoelectric elements having a vibrating portion have been proposed in the past (see, for example, Patent Document 1). Specifically, this piezoelectric element has a configuration in which a vibrating portion having a piezoelectric film and an electrode film electrically connected to the piezoelectric film is stacked on a support. The piezoelectric element has a recess formed in the support, and a part of the vibrating portion forms a floating region floating above the support. In this piezoelectric element, slits are formed in the floating region, dividing the floating region into multiple regions to form the vibrating region. In this piezoelectric element, the slits are formed so as to completely divide the floating region into four regions.

[0003] When pressure such as sound pressure is applied to the vibration region of such a piezoelectric element, the vibration region vibrates, and an electric charge generated in the piezoelectric film is output as a detection signal. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5936154 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the above piezoelectric element, the pressure escapes through the slit, which may narrow the detection band.

[0006] In view of the above, an object of the present invention is to provide a piezoelectric element that can prevent the detection band from narrowing. [Means for solving the problem]

[0007] Claim 1 to achieve the above object and 2 is a piezoelectric element having a vibration part (20) arranged on a support (10), and comprising: the support; and a vibration part arranged on the support and including a piezoelectric film (40) and an electrode film (50) connected to the piezoelectric film, the vibration part having a support region (21a) supported by the support; and a floating region (21b) connected to the support region and floating above the support, the floating region having a plurality of vibration regions (22a to 22d) separated by slits (30), and adjacent vibration regions are connected at the part on the support region side. In claims 1 and 2, the slits are formed so as to reach the support region from the floating region, and adjacent vibration regions are connected at the support region side by an additional thin film (81) that covers the portion of the slit on the support region side, and adjacent vibration regions are connected at the support region side by an additional thin film (82) that covers the portion of the slit on the opposite side to the support region side. Furthermore, in claim 1, the additional thin film arranged on the side opposite the support region side is thicker and has a larger Young's modulus than the additional thin film arranged on the support region side. In claim 2, the additional thin film arranged on the side opposite the support region side is thinner and has a smaller Young's modulus than the additional thin film arranged on the support region side.

[0008] According to this, adjacent vibration regions are connected at the support region side. Therefore, the opening area of the slit can be made smaller compared to when adjacent vibration regions are completely separated. Therefore, it is possible to prevent the detection band from narrowing by reducing the low-frequency roll-off frequency. Furthermore, compared to when adjacent vibration regions are connected at the support region side and the opposite side, the influence on the vibration of each vibration region caused by connecting the vibration regions is likely to be smaller, and it is possible to prevent a decrease in detection sensitivity.

[0009] The reference symbols in parentheses attached to each component indicate an example of the correspondence between the component and the specific components described in the embodiments described below. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 2 is a plan view of the piezoelectric element according to the first embodiment. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Figure 3] FIG. 2 is a cross-sectional view taken along line III-III in FIG. [Figure 4] FIG. 10 is a diagram showing the relationship between the coverage of the slit with the additional thin film and the roll-off frequency and the decrease in sensitivity. [Figure 5] FIG. 10 is a plan view of a piezoelectric element according to a second embodiment. [Figure 6] 6 is a cross-sectional view of the vibration part and the additional thin film taken along the line VI-VI in FIG. 5. [Figure 7] 7 is a cross-sectional schematic view of the vibration part and the additional thin film taken along line VII-VII in FIG. 5. [Figure 8] FIG. 10 is a plan view of a piezoelectric element according to a third embodiment. [Figure 9] FIG. 11 is a plan view of a piezoelectric element according to a modified example of the third embodiment. [Figure 10] FIG. 10 is a plan view of a piezoelectric element according to a fourth embodiment. [Figure 11] FIG. 10 is a plan view of a piezoelectric element according to a fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following embodiments, identical or equivalent parts will be denoted by the same reference numerals.

[0012] (First embodiment) The piezoelectric element of the first embodiment will be described with reference to Figures 1 to 3. The piezoelectric element of this embodiment is suitable for use in a piezoelectric microphone mounted on a smartphone, an AI (artificial intelligence) speaker, etc. The piezoelectric element of this embodiment is also suitable for use in an ultrasonic sensor, etc.

[0013] 1 to 3, the piezoelectric element includes a support 10 and a vibration part 20 disposed on the support 10, and has a rectangular planar shape. The support 10 includes a support substrate 11 having one surface 11a, and an insulating film 12 formed on the one surface 11a of the support substrate 11. The support substrate 11 is made of, for example, a silicon substrate, and the insulating film 12 is made of, for example, an oxide film.

[0014] A recess 10a is formed in the support 10 to float the inner edge side of the vibration section 20. Therefore, the vibration section 20 has a configuration including a support region 21a arranged on the support 10 and a floating region 21b that is connected to the support region 21a and floats above the recess 10a. In this embodiment, the opening end of the recess 10a on the vibration section 20 side has a rectangular shape in plan view. Therefore, the entire floating region 21b has a rectangular shape in plan view.

[0015] Furthermore, in the vibrating section 20 of this embodiment, an opening 20a is formed in the outer edge portion thereof, exposing the outer edge portion of the insulating film 12. An opening 12a is formed in the outer edge portion of the insulating film 12, exposing the outer edge portion of the support substrate 11. Therefore, the outer edge portion of the support substrate 11 is exposed from the insulating film 12 and the vibrating section 20. Note that the opening 12a formed in the insulating film 12 and the opening 20a formed in the vibrating section 20 are intended to facilitate the dicing process when manufacturing the piezoelectric element, and are not necessarily required to be formed.

[0016] The floating region 21b is formed with slits 30 penetrating the floating region 21b in the thickness direction. In this embodiment, the slits 30 are formed so as to divide the floating region 21b into four parts. Specifically, two slits 30 are formed so as to pass through the center C of the floating region 21b and extend toward opposite corners of the floating region 21b. In other words, the slits 30 extend from each corner of the floating region 21b, which has a rectangular planar shape, toward the center C, and are formed so that the slits 30 intersect at the center C. As a result, the floating region 21b is divided into first to fourth vibration regions 22a to 22d, each of which has a substantially triangular planar shape. Although not particularly limited, in this embodiment, the interval between the vibration regions 22a to 22d (i.e., the width of the slits 30) is approximately 1 μm. In addition, in this embodiment, the slits 30 extend to the support region 21a, but may be formed so as to terminate at the boundary between the floating region 21b and the support region 21a.

[0017] The first to fourth vibration regions 22a to 22d are configured as described above, so that the end on the support region 21a side is a fixed end, and the tip end (hereinafter simply referred to as the tip end) on the opposite side to the support region 21a is a cantilever that is a free end.

[0018] The vibration section 20 is configured to have a piezoelectric film 40 and an electrode film 50 connected to the piezoelectric film 40. Specifically, the piezoelectric film 40 has a lower-layer piezoelectric film 41 and an upper-layer piezoelectric film 42 laminated on the lower-layer piezoelectric film 41. The lower-layer piezoelectric film 41 and the upper-layer piezoelectric film 42 are made of lead-free piezoelectric ceramics such as scandium aluminum nitride (ScAlN) and aluminum nitride (AlN). The lower-layer piezoelectric film 41 and the upper-layer piezoelectric film 42 are made of lead zirconate titanate (PZT) or the like.

[0019] The electrode film 50 is formed on each of the vibration regions 22a to 22d so as to be connected to the piezoelectric film 40, and is made of molybdenum (Mo). However, the electrode film 50 may be made of a metal material other than molybdenum, such as titanium (Ti), platinum (Pt), aluminum (Al), or ruthenium (Ru).

[0020] In this embodiment, the electrode films 50 include a lower electrode film 51 formed below the lower piezoelectric film 41, an intermediate electrode film 52 formed between the lower piezoelectric film 41 and the upper piezoelectric film 42, and an upper electrode film 53 formed above the upper piezoelectric film 42. The lower electrode film 51 and the intermediate electrode film 52 are arranged to face each other with the lower piezoelectric film 41 in between. The intermediate electrode film 52 and the upper electrode film 53 are arranged to face each other with the upper piezoelectric film 42 in between.

[0021] As will be described later, the piezoelectric element of this embodiment outputs, as a detection signal, the charge that changes as each of the vibration regions 22a to 22d vibrates. The piezoelectric element of this embodiment is configured to output the change in charge in the first to fourth vibration regions 22a to 22d as a single pressure detection signal. Specifically, the electrode films 50 of the first to fourth vibration regions 22a to 22d are electrically connected in series via wiring (not shown). More specifically, the first vibration region 22a to 22d has a so-called bimorph structure. The lower electrode films 51, intermediate electrode films 52, and upper electrode films 53 formed in each of the vibration regions 22a to 22d are connected in parallel, and the vibration regions 22a to 22d are connected in series.

[0022] The piezoelectric element is formed with a first electrode portion 61 and a second electrode portion 62 so as to be connected to end portions of the series-connected electrode films 50 of the first to fourth vibration regions 22a to 22d. Specifically, the first electrode portion 61 has a first through electrode 61b and a first pad portion 61c, and is formed in the support region 21a so as to be connected to the lower-layer electrode film 51 and the upper-layer electrode film 53 formed in the first vibration region 22a. The second electrode portion 62 has a second through electrode 62b and a second pad portion 62c, and is formed in the support region 21a so as to be electrically connected to the intermediate electrode film 52 formed in the fourth vibration region 22d.

[0023] 2, the lower electrode film 51 and the upper electrode film 53 formed in the first vibration region 22a extend to the support region 21a. A first hole 61a is formed to penetrate the upper piezoelectric film 42 and the lower piezoelectric film 41 to expose the lower electrode film 51, and a first through electrode 61b is disposed in the first hole 61a so as to be electrically connected to the lower electrode film 51. A first pad 61c is disposed on the upper piezoelectric film 42 so as to be electrically connected to the first through electrode 61b and the upper electrode film 53.

[0024] 3, the intermediate electrode film 52 formed in the fourth vibration region 22d extends to the support region 21a. A second hole 62a is formed so as to penetrate the upper-layer piezoelectric film 42 and expose the intermediate electrode film 52, and a second through-electrode 62b is disposed in the second hole 62a so as to be electrically connected to the intermediate electrode film 52. A second pad 62c is disposed on the upper-layer piezoelectric film 42 so as to be electrically connected to the second through-electrode 62b.

[0025] Furthermore, the vibration section 20 of this embodiment has a buffer layer 70 on the support 10 side, on which the lower piezoelectric film 41 and the lower electrode film 51 are arranged. The buffer layer 70 is made of, for example, aluminum nitride (AlN) or the like.

[0026] In the piezoelectric element of this embodiment, an additional thin film 81 is provided so as to cover a part of the slit 30 formed in the floating region 21b. Specifically, the additional thin film 81 is disposed in a part of the slit 30 that is located on the support region 21a side. The additional thin film 81 is also formed so as to connect the adjacent vibrating regions 22a to 22d via the slit 30. Therefore, the vibrating regions 22a to 22d are connected at the part on the support region 21a side.

[0027] In this embodiment, the additional thin film 81 is formed from the support region 21 a side to the floating region 21 b. However, the additional thin film 81 may be formed only in the floating region 21 b, or may be arranged so that the end of the slit 30 on the support region 21 a side is exposed from the additional thin film 81.

[0028] The additional thin film 81 is intended to make it difficult for pressure to escape from the slit 30. For this reason, the additional thin film 81 may be arranged inside the slit 30, or may not be arranged inside the slit 30. The additional thin film 81 is preferably made of a material with a low Young's modulus so as to be less likely to affect the vibration of each of the vibrating regions 22a to 22d, and is made of, for example, an organic material containing urethane.

[0029] The above is the structure of the piezoelectric element in this embodiment. When pressure such as sound pressure is applied to each of the vibration regions 22a to 22d of this piezoelectric element, the vibration regions 22a to 22d vibrate. Then, for example, when the tip end side (i.e., the free end side) of each of the vibration regions 22a to 22d is displaced upward, tensile stress is generated in the lower-layer piezoelectric film 41, and compressive stress is generated in the upper-layer piezoelectric film 42. Therefore, by extracting the charge from the first electrode portion 61 and the second electrode portion 62, pressure such as sound pressure can be detected.

[0030] In this embodiment, the slit area is reduced by the additional thin film 81. This makes it difficult for pressure to escape from the slit 30, and as shown in FIG. 4, the detection band can be widened by reducing the roll-off frequency. Note that the sensitivity reduction in FIG. 4 shows the simulation results when the sound pressure is set to 1 kHz. The slit area here refers to the area of the slit 30 when viewed from the stacking direction of the support 10 and the vibration part 20, that is, the opening area of the slit 30.

[0031] In this case, the larger the slit 30 covered by the additional thin film 81, the smaller the roll-off frequency can be, but the larger the slit 30 covered by the additional thin film 81, the more the vibration of each vibration region 22a to 22d is hindered, resulting in a decrease in sensitivity. Therefore, it is preferable that the area of the slit 30 covered by the additional thin film 81 be adjusted according to the required performance.

[0032] 1, the length of the slit 30 along the longitudinal direction is defined as length L1, and the length of the additional thin film 81 along the longitudinal direction of the slit 30 is defined as length L2. In this case, according to the studies of the present inventors, it has been confirmed that when the length L1 of the slit 30 is set to 477 μm, the roll-off frequency can be set to about 20 Hz by setting the length L2 of the additional thin film 81 to 250 μm. Setting the roll-off frequency to 20 Hz means matching the roll-off frequency to a frequency on the low frequency side of the audible range.

[0033] 1, if the length of the additional thin film 81 in the direction intersecting the longitudinal direction of the slit 30 is defined as width d, the narrower the width d, the less the additional thin film 81 affects the vibration of each of the vibration regions 22a to 22d. Here, the additional thin film 81 of this embodiment is made using an organic material as described above. And, this additional thin film 81 is made, for example, by applying an organic material and patterning it. For this reason, taking into account manufacturing limitations and simplification of the manufacturing process, it is preferable that the additional thin film 81 be formed so that the width d is less than the sum of the width of the slit 30 and 15 μm.

[0034] According to the present embodiment described above, the additional thin film 81 is provided so as to cover the portion of the slit 30 on the support region 21a side, and the adjacent vibration regions 22a to 22d are connected at the portion on the support region 21a side. This allows the opening area of the slit 30 to be reduced, and the narrowing of the detection band due to the reduction in the low-frequency roll-off frequency can be suppressed.

[0035] Furthermore, the additional thin film 81 is provided so as to cover the portion of the slit 30 on the support region 21a side. Therefore, compared to when the additional thin film 81 is provided on the portion of the slit 30 opposite the support region 21a, the additional thin film 81 is less likely to affect the vibration of each of the vibrating regions 22a to 22d, and a decrease in detection sensitivity can be suppressed.

[0036] (1) In this embodiment, the additional thin film 81 is provided so as to cover the portion of the slit 30 on the support region 21a side. Therefore, the opening area of the slit 30 can be easily adjusted.

[0037] (Second embodiment) A second embodiment will be described. This embodiment is the same as the first embodiment except that an additional thin film is added. As the rest of the configuration is the same as the first embodiment, a description thereof will be omitted here.

[0038] 5 to 7, the piezoelectric element of this embodiment is provided with an additional thin film 82 that covers the portion of the slit 30 formed in the floating region 21b on the side opposite the support region 21a. In other words, the piezoelectric element is also provided with an additional thin film 82 on the portion of the slit 30 that defines the free end sides of the first to fourth vibration regions 22a to 22d. Therefore, the free end sides of the vibration regions 22a to 22d are also connected. Hereinafter, in this embodiment, the additional thin film 81 that covers the portion of the slit 30 on the side of the support region 21a will be referred to as the fixed end side additional thin film 81, and the additional thin film 82 that covers the portion of the slit 30 on the side opposite the support region 21a will be referred to as the free end side additional thin film 82.

[0039] 6 and 7 show a simplified shape of the vibration section 20, but in reality, the vibration section 20 is formed as shown in FIGS. 2 and 3. Also, while FIG. 6 shows a diagram in which the free-end-side additional thin film 82 is arranged so as to fill the slit 30, the free-end-side additional thin film 82 does not have to be arranged so as to fill the slit 30. Similarly, FIG. 7 shows a diagram in which the fixed-end-side additional thin film 81 is arranged so as to fill the slit 30, but the fixed-end-side additional thin film 81 does not have to be arranged so as to fill the slit 30.

[0040] The free end side additional thin film 82 is thicker than the fixed end side additional thin film 81. The free end side additional thin film 82 also has a larger Young's modulus than the fixed end side additional thin film 81. For example, the free end side additional thin film 82 is made of polyimide or the like with a Young's modulus of about 4 GPa, and has a thickness of about 3 μm. On the other hand, the fixed end side additional thin film 81 is made of urethane or the like with a Young's modulus of about 0.1 GPa, and has a thickness of about 1 μm.

[0041] According to the present embodiment described above, the additional thin film 81 is provided so as to cover the portion of the slit 30 on the support region 21a side, and therefore, the same effects as those of the first embodiment can be obtained.

[0042] (1) In this embodiment, the free end side additional thin film 82 is disposed on the portion of the slit 30 opposite the support region 21a side. This prevents the free end side of the vibrating regions 22a to 22d from warping due to residual stress in each of the vibrating regions 22a to 22d that occurs when manufacturing the piezoelectric element. This prevents the slit area from increasing and the detection band from decreasing.

[0043] (2) In this embodiment, the free end side additional thin film 82 is thicker and has a larger Young's modulus than the fixed end side additional thin film 81. Therefore, warping due to residual stress can be further reduced compared to when the free end side additional thin film 82 is thinner and has a smaller Young's modulus than the fixed end side additional thin film 81.

[0044] (Modification of the second embodiment) A modification of the second embodiment will be described. In the second embodiment, the free-end side additional thin film 82 may be thinner and have a smaller Young's modulus than the fixed-end side additional thin film 81. This makes it possible to suppress the free-end side additional thin film 82 from affecting the vibration of each of the vibrating regions 22a to 22d, and to suppress a decrease in detection sensitivity, compared to when the free-end side additional thin film 82 is thicker and has a larger Young's modulus than the fixed-end side additional thin film 81.

[0045] (Third embodiment) A third embodiment will be described. This embodiment is different from the second embodiment in that the shape of the tip end side of each of the vibration regions 22a to 22d is changed. As the rest is the same as the second embodiment, a description thereof will be omitted here.

[0046] 8, in the piezoelectric element of this embodiment, each of the vibrating regions 22a to 22d has a rounded tip end so as to reduce the portion that overlaps with the free-end-side additional thin film 82 in the stacking direction. In other words, each of the vibrating regions 22a to 22d has a chamfered tip end.

[0047] According to the present embodiment described above, the additional thin film 81 is provided so as to cover the portion of the slit 30 on the support region 21a side, and therefore, the same effects as those of the first embodiment can be obtained.

[0048] (1) In this embodiment, the tip end side of each of the vibrating regions 22a to 22d is rounded so as to reduce the portion that overlaps with the free end side additional thin film 82 in the stacking direction. This makes it even more difficult for the free end side additional thin film 82 to affect the vibration of each of the vibrating regions 22a to 22d, thereby further suppressing a decrease in detection sensitivity.

[0049] (Modification of the third embodiment) A modification of the third embodiment will be described. In the third embodiment, each of the vibrating regions 22a to 22d may have a trapezoidal shape with a chamfered tip end. Even with such a piezoelectric element, the free-end-side additional thin film 82 is less likely to affect the vibration of each of the vibrating regions 22a to 22d, and the same effect as the third embodiment can be obtained.

[0050] (Fourth embodiment) A fourth embodiment will be described. This embodiment is different from the first embodiment in that the shape of the additional thin film 81 is changed. As the rest is the same as the first embodiment, a description thereof will be omitted here.

[0051] In the piezoelectric element of this embodiment, the additional thin film 81 has a planar elliptical shape in the stacking direction, as shown in Fig. 10. In other words, the additional thin film 81 has a planar shape with chamfered corners.

[0052] According to the present embodiment described above, the additional thin film 81 is provided so as to cover the portion of the slit 30 on the support region 21a side, and therefore, the same effects as those of the first embodiment can be obtained.

[0053] (1) In this embodiment, the additional thin film 81 has a planar shape with chamfered corners in the stacking direction. This makes it possible to prevent stress from concentrating at a specific location on the additional thin film 81, and to prevent the additional thin film 81 from peeling off. Although not particularly shown, the free-end-side additional thin film 82 of the second and third embodiments also has a planar shape with chamfered corners, which makes it possible to prevent the free-end-side additional thin film 82 from peeling off.

[0054] (Fifth embodiment) A fifth embodiment will be described. This embodiment is different from the first embodiment in that the shape of the slit 30 is changed. As the rest is the same as the first embodiment, a description thereof will be omitted here.

[0055] 11, in the piezoelectric element of this embodiment, the slits 30 are not formed to reach the corners of the floating region 21b, which has a rectangular shape in plan view, but are shaped to terminate within the floating region 21b. Therefore, the vibrating regions 22a to 22d are connected at the portion on the support region 21a side.

[0056] According to the present embodiment described above, the slits 30 are formed so that the vibrating regions 22a to 22d are connected at the portion on the support region 21a side, thereby reducing the opening area of the slits 30. Therefore, the same effects as those of the first embodiment can be obtained.

[0057] (Other embodiments) Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and modifications within the scope of equivalents. In addition, various combinations and forms, as well as other combinations and forms including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

[0058] For example, in each of the above embodiments, the floating region 21b may have a polygonal planar shape such as a pentagonal, hexagonal, or octagonal shape instead of a rectangular shape. The number of vibration regions 22a to 22d formed in the floating region 21b can be changed as appropriate. Furthermore, the piezoelectric element may have a polygonal planar shape such as a pentagonal or hexagonal shape instead of a rectangular shape.

[0059] In each of the above embodiments, the vibration section 20 only needs to be configured to have at least one layer of piezoelectric film 40 and one layer of electrode film 50.

[0060] In each of the above embodiments, the opening 20a formed in the vibrating portion 20 and the opening 12a formed in the insulating film 12 may not be formed in the piezoelectric element.

[0061] Furthermore, in each of the above embodiments, each of the vibration regions 22a to 22d may output its own charge as a detection signal. In this case, a first electrode portion 61 is connected to the lower electrode film 51 and the upper electrode film 53 of each of the vibration regions 22a to 22d, and a second electrode portion 62 is connected to the intermediate electrode film 52 of each of the vibration regions 22a to 22d.

[0062] The above embodiments can also be combined. For example, the second and third embodiments can be combined with the fourth embodiment, so that the planar shape of the free end side additional thin film 82 has chamfered corners. [Explanation of symbols]

[0063] 10 Support 20 Vibration unit 21a Support area 21b Floating region 22a~22d Vibration area 30 slits 40 Piezoelectric film 50 Electrode membrane

Claims

1. A piezoelectric element having a vibration part (20) disposed on a support (10), The support; The vibration unit is disposed on the support, includes a piezoelectric film (40) and an electrode film (50) connected to the piezoelectric film, and has a support region (21a) supported by the support, and a floating region (21b) connected to the support and floating above the support, The floating region has a plurality of vibration regions (22a to 22d) divided by slits (30), The adjacent vibration regions are connected at the support region side, the slit is formed so as to reach the support region from the floating region, The adjacent vibration regions are connected to each other by disposing an additional thin film (81) that covers the support region side portion of the slit, and The adjacent vibration regions are connected to each other by disposing an additional thin film (82) that covers the portion of the slit opposite to the support region side, and The additional thin film disposed on the side opposite to the support region has a greater thickness and a greater Young's modulus than the additional thin film disposed on the support region side.

2. A piezoelectric element in which a vibration part (20) is disposed on a support (10), The support; The vibration unit is disposed on the support, includes a piezoelectric film (40) and an electrode film (50) connected to the piezoelectric film, and has a support region (21a) supported by the support, and a floating region (21b) connected to the support and floating above the support, The floating region has a plurality of vibration regions (22a to 22d) divided by slits (30), The adjacent vibration regions are connected at the support region side, the slit is formed so as to reach the support region from the floating region, The adjacent vibration regions are connected to each other by disposing an additional thin film (81) that covers the support region side portion of the slit, and The adjacent vibration regions are connected to each other by disposing an additional thin film (82) that covers the portion of the slit opposite to the support region side, and The additional thin film disposed on the side opposite to the support region has a smaller thickness and a smaller Young's modulus than the additional thin film disposed on the support region side.

3. 3. The piezoelectric element according to claim 1, wherein the additional thin film has a flat shape with chamfered corners.

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