JP7434732B2 - Piezoelectric element - Google Patents

Description

The present disclosure relates to piezoelectric elements.

2. Description of the Related Art A piezoelectric element is known that has a first main surface and a second main surface facing each other, and is provided with a slit that divides the first main surface (for example, see Patent Document 1). In the ultrasonic transducer described in Patent Document 1, the flow rate and flow velocity of gas or liquid are measured using ultrasonic waves.

Japanese Patent Application Publication No. 2003-348681

In the piezoelectric element as described above, polarization deformation becomes large on the first main surface side divided by the slit, and the planar state of the first main surface deteriorates. When such a first main surface is bonded to a flat vibration member, the state of bonding between the first main surface and the vibration member varies within the first main surface. As a result, vibration transmissibility is reduced.

One aspect of the present disclosure provides a piezoelectric element that can suppress a decrease in vibration transmissibility.

A piezoelectric element according to one aspect of the present disclosure has a polygonal shape, a first main surface and a second main surface facing each other, and a plurality of ridgeline portions extending in opposing directions of the first main surface and the second main surface, A piezoelectric element having a slit that divides the first main surface, and one of the plurality of ridgeline sections has a chamfered shape at the end on the first main surface side. .

In this piezoelectric element, polarization deformation is larger on the first main surface side divided by the slits than on the second main surface side not divided by the slits. Therefore, the planar state of the first main surface is more likely to deteriorate than the planar state of the second main surface. Therefore, for example, when the first main surface is joined to a flat vibration member, the state of joining between the first main surface and the vibration member varies within the first main surface. In particular, on the first principal surface, the closer the position of the ridgeline portion to the first principal surface side end, the greater the distance from the vibrating member. In this piezoelectric element, one of the plurality of ridgeline parts has a chamfered part at the end on the first main surface side. In other words, the first main surface does not have at least one portion where the distance from the vibrating member is the greatest. This suppresses variations in the bonding state between the first main surface and the vibrating member. Therefore, it is possible to suppress a decrease in vibration transmissibility.

Each of the plurality of ridgeline portions may have a chamfered shape at the end on the first main surface side. In this case, the first main surface does not have any part where the distance between it and the vibrating member is the largest. Therefore, it is possible to further suppress a decrease in vibration transmissibility.

One ridgeline portion may have a chamfered shape over the entire opposing direction. Also in this case, it is possible to suppress the vibration transmissibility from decreasing.

Each of the plurality of ridgeline portions may have a chamfered shape over the entire opposing direction. Also in this case, it is possible to further suppress a decrease in vibration transmissibility.

The chamfered shape may be planar. Also in this case, it is possible to suppress the vibration transmissibility from decreasing.

The chamfered shape may be curved. Also in this case, it is possible to suppress the vibration transmissibility from decreasing.

According to one aspect of the present disclosure, a piezoelectric element capable of suppressing a decrease in vibration transmissibility is provided.

FIG. 1 is a perspective view showing a piezoelectric element according to a first embodiment. 2 is a cross-sectional view showing the piezoelectric element of FIG. 1. FIG. FIG. 3 is a perspective view showing a piezoelectric element according to a comparative example. FIG. 3 is a perspective view showing a piezoelectric element according to a second embodiment. FIG. 7 is a perspective view showing a piezoelectric element according to a third embodiment. FIG. 7 is a perspective view showing a piezoelectric element according to a fourth embodiment.

Embodiments will be described in detail below with reference to the accompanying drawings. In the description of the drawings, the same or equivalent elements are given the same reference numerals, and redundant description will be omitted.

[First embodiment]
FIG. 1 is a perspective view showing a piezoelectric element according to a first embodiment. FIG. 2 is a sectional view showing the piezoelectric element of FIG. 1. The piezoelectric element 1A shown in FIGS. 1 and 2 is used as a sensor by being joined to a vibrating member (not shown) made of a metal plate such as SUS (stainless steel), for example. The piezoelectric element 1A is used, for example, as an on-vehicle sensor that transmits and receives ultrasonic waves to detect the distance between vehicles, or as a powder level sensor that detects the amount of toner in a copying machine.

The piezoelectric element 1A has, for example, a rectangular parallelepiped shape. The rectangular parallelepiped shape includes a rectangular parallelepiped shape with chamfered corners and edge lines, and a rectangular parallelepiped shape with rounded corners and edge lines. The piezoelectric element 1A has, as its outer surface, a first main surface 1a and a second main surface 1b that face each other, a pair of side faces 1c that face each other, and a pair of side faces 1d that face each other.

The first main surface 1a and the second main surface 1b have a polygonal shape. Each interior angle of the first main surface 1a and the second main surface 1b is less than 180 degrees. The first main surface 1a overlaps the second main surface 1b when viewed from the direction D1 in which the first main surface 1a and the second main surface 1b face each other. In this embodiment, the first main surface 1a and the second main surface 1b have a rectangular shape. The four interior angles of the first main surface 1a and the second main surface 1b are each 90 degrees, for example. The first main surface 1a is, for example, a surface joined to a vibrating member.

The pair of side surfaces 1c have a rectangular shape. The pair of side surfaces 1c have the same shape. The pair of side surfaces 1d have a rectangular shape. The pair of side surfaces 1d have the same shape. The side surface 1c is adjacent to each of the pair of side surfaces 1d. The side surface 1d is adjacent to each of the pair of side surfaces 1c.

The direction D1 in which the first principal surface 1a and the second principal surface 1b face each other, the direction D2 in which the pair of side surfaces 1c oppose each other, and the direction D3 in which the pair of side surfaces 1d oppose each other are mutually intersecting (for example, perpendicular to each other). )are doing. The length of the piezoelectric element 1A in the direction D1 is, for example, 3 mm, the length of the piezoelectric element 1A in the direction D2 is, for example, 8 mm, and the length of the piezoelectric element 1A in the direction D3 is, for example, 8 mm.

The first main surface 1a and the second main surface 1b extend in the direction D2 so as to connect the pair of side surfaces 1c. The first main surface 1a and the second main surface 1b also extend in the direction D3 so as to connect the pair of side surfaces 1d. The pair of side surfaces 1c extend in the direction D1 so as to connect the first main surface 1a and the second main surface 1b. The pair of side surfaces 1c also extend in the direction D3 so as to connect the pair of side surfaces 1d. The pair of side surfaces 1d extend in the direction D1 so as to connect the first main surface 1a and the second main surface 1b. The pair of side surfaces 1d also extend in the direction D2 so as to connect the pair of side surfaces 1c.

The piezoelectric element 1A has a plurality of (here, four) ridgeline portions 1e, a plurality of (here, four) corner portions A1, and a plurality of (here, four) corner portions A2. The ridgeline portion 1e is located between the side surface 1c and the side surface 1d that are adjacent to each other, and extends in the direction D1 so as to connect the first main surface 1a and the second main surface 1b. The ridgeline portion 1e includes an end portion 1f on the first main surface 1a side and an end portion 1g on the second main surface 1b side.

The plurality of corner portions A1 are located at each end portion 1f of the plurality of ridgeline portions 1e. The plurality of corner portions A1 are located between the side surface 1c and the side surface 1d adjacent to each other and the first main surface 1a. The plurality of corner portions A2 are located at each end portion 1g of the plurality of ridgeline portions 1e. The plurality of corner portions A2 are located between the side surface 1c and the side surface 1d that are adjacent to each other and the second main surface 1b.

The ridgeline portion 1e has a chamfered shape at the end portion 1f. In this embodiment, each of the plurality of ridgeline portions 1e has a chamfered shape at the end portion 1f. The chamfered shape is not limited to the shape formed by actually chamfering the end portion 1f, but may be any shape equivalent thereto. The end portion 1f is located inside a virtual corner formed by intersecting a virtual plane including the side surface 1c, a virtual plane including the side surface 1d, and a virtual plane including the first principal surface 1a. positioned. The chamfered shape of this embodiment refers to a shape continuously provided at least over the piezoelectric body 2 and the electrode 3, which will be described later.

The corner portion A1 has a chamfered shape. In this embodiment, the plurality of corners A1 all have a chamfered shape. The chamfered shape is not limited to a shape formed by actually chamfering the corner portion A1, but may be any shape equivalent to the shape. The corner A1 is located inside a virtual corner formed by intersecting a virtual plane including the side surface 1c, a virtual plane including the side surface 1d, and a virtual plane including the first principal surface 1a. positioned. The chamfered shape of this embodiment refers to a shape that is continuously provided over at least a piezoelectric body 2 and an electrode 3, which will be described later.

In this embodiment, the chamfered shape of the end portion 1f (that is, the chamfered shape of the corner portion A1) is a planar shape inclined with respect to the direction D1. The chamfered shape of the end portion 1f (that is, the chamfered shape of the corner portion A1) is a shape that intersects the side surface 1c, the side surface 1d, and the first main surface 1a, respectively. The chamfered shape of the end portion 1f (that is, the chamfered shape of the corner portion A1) is a triangular shape having one side each on the side surface 1c, the side surface 1d, and the first main surface 1a. It can also be said that the piezoelectric element 1A has a chamfered portion exhibiting a chamfered shape between the side surface 1c and the side surface 1d adjacent to each other and the first main surface 1a.

The piezoelectric element 1A is provided with a plurality of (here, three) slits 5 that divide the first main surface 1a. Specifically, the plurality of slits 5 are provided in a portion of the piezoelectric element 1A closer to the first main surface 1a. The plurality of slits 5 are arranged at equal intervals in the direction D3. The slit 5 extends in the direction D2, and extends from one end of the piezoelectric element 1A in the direction D2 to the other end. The slit 5 does not reach the second main surface 1b. The slit 5 is provided to adjust the resonance frequency, impedance waveform, etc. for sensing, for example, when the piezoelectric element 1A is used as a sensor.

The first main surface 1a is divided by slits 5. The first main surface 1a has a plurality of (four in this case) main surface portions 1a1 divided by a plurality of slits 5. A pair of main surface portions 1a1 that are adjacent to each other in the direction D3 are separated from each other via the slit 5. The plurality of main surface portions 1a1 are arranged at equal intervals in the direction D3. The plurality of main surface portions 1a1 have substantially the same rectangular shape. The main surface portions 1a1 at both ends in the direction D3 differ in shape from the other main surface portions 1a1 in that the corners corresponding to the corners A1 are rounded.

The bottom surface of the slit 5 faces the second main surface 1b in the direction D1. The bottom surface of the slit 5 is provided, for example, in parallel to the first main surface 1a and the second main surface 1b. The distances between the bottom surfaces of the plurality of slits 5 and the second main surface 1b are equal to each other. That is, the lengths of the plurality of slits 5 in the direction D1 are equal to each other.

The length of the slit 5 in the direction D1 (the depth of the slit 5) is, for example, 2.6 mm. The length of the slit 5 in the direction D2 matches the length of the piezoelectric body 2 in the direction D2, and is, for example, 8 mm. The length of the slit 5 in the direction D3 (the width of the slit 5) is, for example, 0.3 mm. The distance between the slit 5 and the second main surface 1b in the direction D1 is, for example, 0.4 mm.

The piezoelectric element 1A has a plurality of (here, four) divided portions 11 divided by a plurality of slits 5, and a plurality of (here, three) connecting portions 12 that connect the plurality of divided portions 11 to each other. are doing.

The plurality of divided portions 11 have substantially the same shape as each other. The divided portions 11 at both ends in the direction D3 differ in shape from the other divided portions 11 in that they have a chamfered ridgeline portion 1e. A pair of divided portions 11 adjacent in the direction D3 are separated from each other via the slit 5. The divided portion 11 does not overlap the slit 5 when viewed from the direction D1. The divided portion 11 includes a part of the first main surface 1a (main surface part 1a1) and a part of the second main surface 1b. The divided portion 11 extends from the first main surface 1a to the second main surface 1b.

For example, the plurality of connecting portions 12 have the same shape. The connecting portion 12 overlaps the slit 5 when viewed from the direction D1. The connecting portion 12 includes the bottom surface of the slit 5 and a part of the second main surface 1b. The connecting portion 12 extends from the bottom surface of the slit 5 to the second main surface 1b. The connecting portion 12 constitutes the bottom of the slit 5. The connecting portion 12 is arranged between a pair of divided portions 11 adjacent to each other in the direction D3, and connects the pair of divided portions 11 adjacent to each other in the direction D3.

The piezoelectric element 1A includes, for example, a piezoelectric body 2, an electrode 3, and an electrode 4. The piezoelectric body 2 has, for example, a rectangular parallelepiped shape. The rectangular parallelepiped shape includes a rectangular parallelepiped shape with chamfered corners and edge lines, and a rectangular parallelepiped shape with rounded corners and edge lines. The piezoelectric body 2 has, as its outer surface, a main surface 2a and a main surface 2b that face each other. The main surface 2a has substantially the same shape as the first main surface 1a. The main surface 2b has the same shape as the second main surface 1b.

The main surface 2a has a plurality of (four in this case) main surface portions two a1 divided by a plurality of slits 5. A pair of main surface portions two a1 adjacent in the direction D3 are separated from each other with a slit 5 interposed therebetween. The plurality of main surface portions two a1 are arranged at equal intervals in the direction D3. The plurality of main surface portions two a1 have substantially the same rectangular shape. The principal surface portions two a1 at both ends in the direction D3 differ in shape from the other principal surface portions two a1 in that the corners corresponding to the corner portions A1 are rounded.

The piezoelectric body 2 is made of piezoelectric material. In this embodiment, the piezoelectric body 2 is made of a piezoelectric ceramic material. Examples of piezoelectric ceramic materials include those whose main component is lead zirconate titanate (PZT), to which elements such as Nb, Zn, Ni, or Sr are added.

The electrode 3 is provided on the main surface 2a. The electrode 3 is provided over the entire main surface 2a except for a slit 5 portion, which will be described later. The electrode 3 has a main surface 3a and a main surface 3b that face each other in the direction D1. The main surface 3a constitutes the first main surface 1a of the piezoelectric element 1A. Therefore, the electrode 3 has the first main surface 1a. The main surface 3a has substantially the same shape as the first main surface 1a. The main surface 3b faces the main surface 2a of the piezoelectric body 2 in the direction D1. The thickness of the electrode 3 (length in direction D1) is, for example, 5 μm.

The electrode 3 has a plurality of (four in this case) electrode portions 31 divided by a plurality of slits 5, which will be described later. A pair of electrode portions 31 adjacent in direction D3 are spaced apart from each other with slit 5 interposed therebetween. The plurality of electrode portions 31 are provided on the plurality of main surface portions two a1, respectively. The plurality of electrode portions 31 are respectively provided on the entirety of the plurality of main surface portions two a1.

The electrode 4 is provided on the main surface 2b. The electrode 4 has a main surface 4a and a main surface 4b that face each other in the direction D1. The main surface 4a faces the main surface 2b of the piezoelectric body 2 in the direction D1. The main surface 4b constitutes the second main surface 1b of the piezoelectric element 1A. Therefore, the electrode 4 has the second main surface 1b. The main surface 4b has the same shape as the second main surface 1b and the main surface 2b. The thickness of the electrode 4 (length in the direction D1) is, for example, equivalent to the thickness of the electrode 3. The thickness of the electrode 4 is, for example, 5 μm.

An example of a method for manufacturing the piezoelectric element 1A will be described. First, a polyvinyl binder, water, and the like are added to piezoelectric ceramic material powder to form a piezoelectric ceramic paste. Next, a piezoelectric ceramic paste is filled into a mold of a predetermined size and press-molded at a pressure of, for example, 40 MPa. Ceramic green is thereby obtained. Subsequently, the ceramic green is subjected to a binder removal treatment. The binder removal process is performed, for example, at 400° C. for 12 hours. Next, the ceramic green is fired. Firing is performed, for example, at 1250° C. for 4 hours. Thereby, a piezoelectric body is obtained.

Next, the piezoelectric body is lapped and formed into a plate shape having a thickness of 3.2 mm, for example. Subsequently, a conductive paste is applied to both main surfaces of the piezoelectric body. The conductive paste is formed, for example, by adding a binder, a plasticizer, an organic solvent, etc. to powder of a conductive material such as Ag. The conductive paste is applied to a thickness of 10 μm, for example by screen printing. Subsequently, the outer periphery of the piezoelectric body is ground and slits are processed. After that, a conductive paste baking process is performed. The baking process is performed, for example, at 800° C. for 20 minutes.

Next, a chamfering process (that is, a cornering process) is performed on the end of the ridgeline part. The chamfering process is performed using, for example, a grinder. By chamfering, for example, a triangular pyramid-shaped portion having a length of 3 mm along each of the ridge lines along the direction D1, the direction D2, and the direction D3 is removed from the end of the ridge line portion. Next, polarization treatment is performed. The polarization treatment is performed, for example, at 150° C. by applying a voltage with an electric field strength of 3.5 kV/mm to the electrodes of the piezoelectric element for 5 minutes. Thereby, a piezoelectric element is obtained.

FIG. 3 is a perspective view showing a piezoelectric element according to a comparative example. As shown in FIG. 3, in the piezoelectric element 100 according to the comparative example, the ridgeline portion 1e does not have a chamfered shape (that is, the corner A1 does not have a chamfered shape). 1)). Both the piezoelectric element 1A and the piezoelectric element 100 are polarized and deformed by the polarization process. For illustrative purposes, polarization deformation is emphasized in FIG. 3 .

On the second main surface 1b side that is not divided by the slit 5, the divided parts 11 (see FIG. 2) are connected to each other by the connecting parts 12 (see FIG. 2), so deformation is restricted and it is difficult to deform freely. . On the other hand, on the first main surface 1a side divided by the slits 5, the divided portions 11 are spaced apart from each other, so that they are easily deformed freely. Therefore, the polarization deformation is larger on the first main surface 1a side than on the second main surface 1b side. Therefore, the piezoelectric element 1A and the piezoelectric element 100 are curved and deformed such that the first main surface 1a is on the outside of the curve and the second main surface 1b is on the inside of the curve, and the planar state of the first main surface 1a is different from that of the second main surface. The flat state of surface 1b is more likely to deteriorate.

When the first main surface 1a in such a planar state is joined to a flat vibration member (not shown), the state of joining between the first main surface 1a and the vibration member varies within the first main surface 1a. In particular, in the first principal surface 1a, the closer the position is to the corner A1, the greater the distance between the first main surface 1a and the vibrating member, so that the bonding state with the vibrating member is likely to deteriorate. As a result of variations in the bonding state, the transmission of vibration between the piezoelectric element 100 and the vibrating member is reduced.

In contrast, in the piezoelectric element 1A, the ridgeline portion 1e has a chamfered shape. In other words, the corner A1 has a chamfered shape. For this reason, the first main surface 1a of the piezoelectric element 1A does not have a portion corresponding to the portion of the first main surface 1a of the piezoelectric element 100 where the distance to the vibrating member is greatest. This suppresses variations in the bonding state between the first main surface 1a and the vibrating member. Therefore, it is possible to suppress a decrease in vibration transmissibility.

In the piezoelectric element 1A, each of the plurality of ridgeline portions 1e has a chamfered shape at the end portion 1f. Therefore, the first main surface 1a does not have any part corresponding to the part of the first main surface 1a of the piezoelectric element 100 where the distance between the first main surface 1a and the vibrating member is the largest. Therefore, it is possible to further suppress a decrease in vibration transmissibility.

In the piezoelectric element 1A, a ridgeline between the side surface 1c and the first main surface 1a, a ridgeline between the side surface 1d and the first main surface 1a, a ridgeline between the side surface 1c and the second main surface 1b, and The ridgeline portion between the side surface 1d and the second main surface 1b does not have a chamfered shape. Thereby, the vibration generation area of the piezoelectric element 1A is suppressed from decreasing, and a desired amount of vibration can be ensured.

[Second embodiment]
FIG. 4 is a perspective view showing a piezoelectric element according to a second embodiment. The piezoelectric element 1B shown in FIG. 4 differs from the piezoelectric element 1A shown in FIG. 1 mainly in that the ridgeline portion 1e has a chamfered shape over the entire direction D1. In this embodiment, each of the plurality of ridgeline portions 1e has a chamfered shape over the entire direction D1.

The chamfered shape is not limited to a shape formed by actually chamfering the ridgeline portion 1e, but may be any shape equivalent thereto. The ridgeline part 1e is located inside a virtual ridgeline part formed by intersecting a virtual plane including the side surface 1c, a virtual plane including the side surface 1d, and a virtual plane including the first main surface 1a. positioned.

In this embodiment, the chamfered shape of the ridgeline portion 1e is a planar shape parallel to the direction D1. The chamfered shape of the ridgeline portion 1e is a shape that intersects the side surface 1c, the side surface 1d, the first main surface 1a, and the second main surface 1b, respectively. The chamfered shape of the ridgeline portion 1e is a rectangular shape having one side each on the side surface 1c, the side surface 1d, the first main surface 1a, and the second main surface 1b. In this embodiment, the space between the ridgeline portion 1e and the first main surface 1a is not chamfered, but may be chamfered. It can also be said that the piezoelectric element 1B has a chamfered portion exhibiting a chamfered shape between the side surface 1c and the side surface 1d that are adjacent to each other. It can be said that the piezoelectric element 1B has a substantially octagonal column shape because all the ridgeline portions 1e are chamfered.

Also in the piezoelectric element 1B, like the piezoelectric element 1A, the first principal surface 1a has a portion corresponding to the portion of the first principal surface 1a of the piezoelectric element 100 where the distance between the piezoelectric element 1B and the vibrating member is the largest. do not have. Therefore, it is possible to suppress a decrease in vibration transmissibility.

[Third embodiment]
FIG. 5 is a perspective view showing a piezoelectric element according to a third embodiment. The piezoelectric element 1C shown in FIG. 5 differs from the piezoelectric element 1A shown in FIG. 1 mainly in that the chamfered shape of the end portion 1f (that is, the chamfered shape of the corner portion A1) is curved. There is. The end portion 1f (that is, the corner portion A1) has a rounded shape. In this embodiment, each of the plurality of ridgeline portions 1e has a curved chamfered shape at the end portion 1f. In other words, each of the plurality of corner portions A1 has a chamfered shape that is a curved surface.

The chamfered shape is not limited to a shape formed by actually chamfering the end portion 1f into a curved surface shape (that is, chamfering the corner portion A1 into a curved surface shape), but may be any shape equivalent thereto. The end 1f (that is, the corner A1) is a virtual plane formed by intersecting a virtual plane including the side surface 1c, a virtual plane including the side surface 1d, and a virtual plane including the first main surface 1a. It is located inside the imaginary corner and is curved along the imaginary corner. The end portion 1f (that is, the corner portion A1) smoothly connects the side surface 1c, the side surface 1d, and the first main surface 1a to each other. The end portion 1f (that is, the corner portion A1) has a spherical shape. It can also be said that the piezoelectric element 1C has a chamfered portion exhibiting a chamfered shape between the side surface 1c and the side surface 1d adjacent to each other and the first main surface 1a.

Also in the piezoelectric element 1C, like the piezoelectric element 1A, the first main surface 1a has a part corresponding to the part of the first main surface 1a of the piezoelectric element 100 where the distance between it and the vibrating member is the largest. do not have. Therefore, in the piezoelectric element 1C as well, it is possible to suppress a decrease in vibration transmittance between the piezoelectric element 1C and the vibrating member.

[Fourth embodiment]
FIG. 6 is a perspective view showing a piezoelectric element according to a fourth embodiment. The piezoelectric element 1D shown in FIG. 6 is different from the piezoelectric element shown in FIG. It is different from 1A. The ridgeline portion 1e has a rounded shape. In this embodiment, each of the plurality of ridgeline portions 1e has a chamfered shape that is curved over the entire direction D1.

The chamfered shape is not limited to a shape formed by actually chamfering the ridgeline portion 1e into a curved shape, but may be any shape equivalent thereto. The ridgeline part 1e is located inside a virtual ridgeline part formed by intersecting a virtual plane including the side surface 1c, a virtual plane including the side surface 1d, and a virtual plane including the first main surface 1a. It is curved along an imaginary ridgeline. The ridgeline portion 1e smoothly connects the side surface 1c and the side surface 1d to each other. The ridgeline portion 1e is an outwardly convex curve when viewed from the direction D1. It can also be said that the piezoelectric element 1D has a chamfered portion exhibiting a chamfered shape between the side surface 1c and the side surface 1d that are adjacent to each other. In this embodiment, the space between the ridgeline portion 1e and the first main surface 1a is not chamfered, but may be chamfered.

Similarly to the piezoelectric element 1A, in the piezoelectric element 1D, the first principal surface 1a has a portion corresponding to the portion of the first principal surface 1a of the piezoelectric element 100 where the distance from the vibrating member is greatest. do not have. Therefore, in the piezoelectric element 1D as well, it is possible to suppress a decrease in the transmittance of vibration between the piezoelectric element 1D and the vibrating member.

Although the embodiments have been described above, the present invention is not necessarily limited to the embodiments described above, and various changes can be made without departing from the gist thereof.

In the piezoelectric elements 1A, 1B, 1C, and 1D, the ridgeline between the side surface 1c and the first main surface 1a, the ridgeline between the side surface 1d and the first main surface 1a, and the ridgeline between the side surface 1c and the second main surface 1b. The ridgeline portion and the ridgeline portion between the side surface 1d and the second main surface 1b may each have a chamfered shape.

1A, 1B, 1C, 1D... piezoelectric element, 1a... first main surface, 1b... second main surface, 1e... ridgeline portion, 1f... end portion, 5... slit.

Claims (7)

A first main surface and a second main surface each having a rectangular shape and facing each other and each provided with an electrode ;
a plurality of side surfaces extending in a direction facing the first main surface and the second main surface , each of which is not provided with an electrode ;
a plurality of first ridgeline portions extending in opposing directions of the first main surface and the second main surface and located between the adjacent side surfaces;
a plurality of second ridgeline portions located between the first main surface and the plurality of side surfaces;
A piezoelectric element having the second main surface and a plurality of third ridgeline portions located between the plurality of side surfaces,
The piezoelectric element is provided with a slit that divides the first main surface and has a bottom surface where no electrode is provided ,
One of the plurality of first ridgeline portions has a chamfered shape at an end on the first main surface side,
A piezoelectric element, wherein each of the plurality of second ridgeline portions and the plurality of third ridgeline portions has a portion that does not have a chamfered shape. The piezoelectric element according to claim 1, wherein the chamfered shape is a curved shape. A first main surface and a second main surface that have a rectangular shape and are opposite to each other;
a plurality of side surfaces extending in a direction in which the first main surface and the second main surface face each other;
a plurality of first ridgeline portions extending in opposing directions of the first main surface and the second main surface and located between the adjacent side surfaces;
a plurality of second ridgeline portions located between the first main surface and the plurality of side surfaces;
A piezoelectric element having the second main surface and a plurality of third ridgeline portions located between the plurality of side surfaces,
The piezoelectric element is provided with a slit that divides the first main surface,
One of the plurality of first ridgeline portions has a chamfered shape at an end on the first main surface side,
Each of the plurality of second ridgeline portions and the plurality of third ridgeline portions has a portion that does not have a chamfered shape,
In the piezoelectric element, the chamfered shape is planar. The piezoelectric element according to any one of claims 1 to 3 , wherein each of the plurality of first ridgeline portions has the chamfered shape at an end portion on the first main surface side. The piezoelectric element according to any one of claims 1 to 3, wherein the one first ridgeline portion has the chamfered shape throughout the opposing direction. The piezoelectric element according to claim 5 , wherein each of the plurality of first ridgeline portions has the chamfered shape throughout the opposing direction. The piezoelectric element according to any one of claims 1 to 6, wherein the second main surface is not provided with a slit.

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