JP2020205371A - Piezoelectric element - Google Patents

Abstract

To provide a piezoelectric element capable of suppressing a decrease in vibration transmissibility.SOLUTION: A piezoelectric element 1A includes a first main surface 1a and a second main surface 1b which have a polygonal shape and face each other, and a plurality of ridges 1e extending in a direction D1. The piezoelectric element 1A is provided with a slit 5 for dividing the first main surface 1a. One of the plurality of ridges 1e has a chamfered shape at the end 1f on the first main surface 1a side.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to piezoelectric elements.

A piezoelectric element having a first main surface and a second main surface facing each other and provided with a slit for dividing the first main surface is known (see, for example, Patent Document 1). In the ultrasonic vibrator described in Patent Document 1, the flow rate and flow velocity of a gas or liquid are measured by ultrasonic waves.

Japanese Unexamined Patent Publication No. 2003-348681

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

One aspect of the present disclosure provides a piezoelectric element capable of suppressing a decrease in vibration transmissibility.

The piezoelectric element according to one aspect of the present disclosure has a polygonal shape, and has a first main surface and a second main surface facing each other, and a plurality of ridges extending in the opposite directions of the first main surface and the second main surface. It is a piezoelectric element having a structure, and a slit for dividing the first main surface is provided, and one of the plurality of ridges has a chamfered shape at the end on the first main surface side. ..

In this piezoelectric element, the polarization deformation becomes larger on the first main surface side divided by the slit than on the second main surface side not divided by the slit. Therefore, the flat state of the first main surface is more likely to be deteriorated than the flat state of the second main surface. Therefore, for example, when the first main surface is joined to the flat plate-shaped vibrating member, the joining state between the first main surface and the vibrating member varies within the first main surface. In particular, on the first main surface, the closer the ridgeline portion is to the end on the first main surface side, the greater the distance between the ridgeline portion and the vibrating member. In this piezoelectric element, one of the plurality of ridgeline portions has a chamfered portion at the end portion on the first main surface side. That is, the first main surface does not have at least one portion having the largest distance from the vibrating member. As a result, variations in the joint state between the first main surface and the vibrating member are suppressed. Therefore, it is possible to suppress a decrease in vibration transmissibility.

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

One ridge line portion may have a chamfered shape over the entire facing direction. Even in this case, it is possible to suppress a decrease in vibration transmissibility.

The plurality of ridge lines may all have a chamfered shape over the entire facing direction. Even in this case, it is possible to further suppress the decrease in vibration transmissibility.

The chamfered shape may be flat. Even in this case, it is possible to suppress a decrease in vibration transmissibility.

The chamfered shape may be a curved surface. Even in this case, it is possible to suppress a decrease in vibration transmissibility.

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

It is a perspective view which shows the piezoelectric element which concerns on 1st Embodiment. It is sectional drawing which shows the piezoelectric element of FIG. It is a perspective view which shows the piezoelectric element which concerns on a comparative example. It is a perspective view which shows the piezoelectric element which concerns on 2nd Embodiment. It is a perspective view which shows the piezoelectric element which concerns on 3rd Embodiment. It is a perspective view which shows the piezoelectric element which concerns on 4th Embodiment.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same or equivalent elements are designated by the same reference numerals, and duplicate description will be omitted.

[First Embodiment]
FIG. 1 is a perspective view showing a piezoelectric element according to the first embodiment. FIG. 2 is a cross-sectional view showing the piezoelectric element of FIG. 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, in a sensor such as an in-vehicle sensor that transmits and receives ultrasonic waves to detect an inter-vehicle distance, or 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 in which the corners and ridges are chamfered, and a rectangular parallelepiped in which the corners and ridges are rounded. The piezoelectric element 1A has, as its outer surface, a first main surface 1a and a second main surface 1b facing each other, a pair of side surfaces 1c facing each other, and a pair of side surfaces 1d facing each other.

The first main surface 1a and the second main surface 1b have a polygonal shape. Each internal angle of the first main surface 1a and the second main surface 1b is less than 180 degrees. The first main surface 1a overlaps with 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 the present embodiment, the first main surface 1a and the second main surface 1b have a rectangular shape. The four internal angles of the first main surface 1a and the second main surface 1b are, for example, 90 degrees each. 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 as each other. The pair of side surfaces 1d have a rectangular shape. The pair of side surfaces 1d have the same shape as each other. 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 main surface 1a and the second main surface 1b face each other, the direction D2 in which the pair of side surfaces 1c face each other, and the direction D3 in which the pair of side surfaces 1d face each other intersect each other (for example, orthogonal to each other). )doing. The length of the direction D1 of the piezoelectric element 1A is, for example, 3 mm, the length of the direction D2 of the piezoelectric element 1A is, for example, 8 mm, and the length of the direction D3 of the piezoelectric element 1A 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 between the pair of side surfaces 1c. The first main surface 1a and the second main surface 1b extend in the direction D3 so as to connect between the pair of side surfaces 1d. The pair of side surfaces 1c extend in the direction D1 so as to connect between the first main surface 1a and the second main surface 1b. The pair of side surfaces 1c also extends in direction D3 so as to connect between the pair of side surfaces 1d. The pair of side surfaces 1d extend in the direction D1 so as to connect between the first main surface 1a and the second main surface 1b. The pair of side surfaces 1d also extends in direction D2 so as to connect between the pair of side surfaces 1c.

The piezoelectric element 1A has a plurality of (here, four) ridge line portions 1e, a plurality of (here, four) corner portions A1, and a plurality of (here, four) corner portions A2. The ridge line portion 1e is located between the side surface 1c and the side surface 1d 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 ridge line 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 ridge line 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 ridge line portions 1e. The plurality of corner portions A2 are located between the side surface 1c and the side surface 1d adjacent to each other and the second main surface 1b.

The ridge line portion 1e has a chamfered shape at the end portion 1f. In the present embodiment, each of the plurality of ridge line 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, and may be a shape equivalent thereto. The end portion 1f is inside a virtual corner portion 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. The chamfered shape of the present embodiment refers to a shape that is continuously provided over at least the piezoelectric body 2 and the electrode 3 described later.

The corner portion A1 has a squared shape. In the present embodiment, each of the plurality of corner portions A1 has a squared shape. The cornering shape is not limited to the shape formed by actually cornering the corner portion A1, and may be a shape equivalent thereto. The corner portion A1 is inside a virtual corner portion 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. The squared shape of the present embodiment refers to a shape that is continuously provided over at least the piezoelectric body 2 and the electrode 3 described later.

In the present embodiment, the chamfered shape of the end portion 1f (that is, the chamfered shape of the corner portion A1) is a flat 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 on each of the side surface 1c, the side surface 1d, and the first main surface 1a. It can be said that the piezoelectric element 1A has a squared portion having a squared 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 (three in this case) slits 5 for dividing the first main surface 1a. Specifically, the plurality of slits 5 are provided in a portion of the piezoelectric element 1A near 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 reaches from one end to the other end of the direction D2 of the piezoelectric element 1A. The slit 5 does not reach the second main surface 1b. The slit 5 is provided, for example, to adjust the resonance frequency, impedance waveform, and the like for sensing when the piezoelectric element 1A is used for a sensor.

The first main surface 1a is divided by the slit 5. The first main surface 1a has a plurality of (here, four) main surface portions 1a1 divided by the plurality of slits 5. A pair of main surface portions 1a1 adjacent to each other in the direction D3 are separated from each other via a 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 a rectangular shape having substantially the same shape as each other. The main surface portions 1a1 at both ends of the direction D3 are different in shape from the other main surface portions 1a1 in that the corner portions corresponding to the corner portions A1 have a squared shape.

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 with 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 directions D1 of the plurality of slits 5 are equal to each other.

The length of the direction D1 of the slit 5 (depth of the slit 5) is, for example, 2.6 mm. The length of the direction D2 of the slit 5 coincides with the length of the direction D2 of the piezoelectric body 2, and is, for example, 8 mm. The length of the direction D3 of the slit 5 (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 (four in this case) divided portions 11 divided by a plurality of slits 5 and a plurality of (three in this case) connecting portions 12 for connecting the plurality of divided portions 11 to each other. doing.

The plurality of divided portions 11 have substantially the same shape as each other. The divided portions 11 at both ends of the direction D3 are different in shape from the other divided portions 11 in that they have a ridge line portion 1e having a chamfered shape. The pair of divided portions 11 adjacent to each other in the direction D3 are separated from each other through the slit 5. Seen from the direction D1, the divided portion 11 does not overlap with the slit 5. The divided portion 11 includes a part of the first main surface 1a (main surface portion 1a1) and a part of the second main surface 1b. The divided portion 11 reaches from the first main surface 1a to the second main surface 1b.

The plurality of connecting portions 12 have, for example, the same shape as each other. Seen from the direction D1, the connecting portion 12 overlaps with the slit 5. The connecting portion 12 includes a 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 portion 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 in which the corners and ridges are chamfered, and a rectangular parallelepiped in which the corners and ridges are rounded. The piezoelectric body 2 has a main surface 2a and a main surface 2b facing each other as its outer surface. 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 (here, four) main surface portions 2a1 divided by the plurality of slits 5. A pair of main surface portions 2a1 adjacent to each other in the direction D3 are separated from each other via a slit 5. The plurality of main surface portions 2a1 are arranged at equal intervals in the direction D3. The plurality of main surface portions 2a1 have a rectangular shape having substantially the same shape as each other. The main surface portions 2a1 at both ends of the direction D3 are different in shape from the other main surface portions 2a1 in that the corner portions corresponding to the corner portions A1 have a squared shape.

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

The electrode 3 is provided on the main surface 2a. The electrodes 3 are provided on the entire main surface 2a except for the portion of the slit 5 described later. The electrode 3 has a main surface 3a and a main surface 3b facing 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 a 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 (here, four) electrode portions 31 divided by a plurality of slits 5 described later. The pair of electrode portions 31 adjacent to each other in the direction D3 are separated from each other through the slit 5. The plurality of electrode portions 31 are provided on each of the plurality of main surface portions 2a1. The plurality of electrode portions 31 are provided on the entire plurality of main surface portions 2a1.

The electrode 4 is provided on the main surface 2b. The electrode 4 has a main surface 4a and a main surface 4b facing 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 a 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 (the length of the direction D1) is equivalent to, for example, 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 chloride binder, water, or the like is added to the powder of the piezoelectric ceramic material to form a piezoelectric ceramic paste. Next, the piezoelectric ceramic paste is filled in a mold having a predetermined size, and press-molded at a pressure of, for example, 40 MPa. This gives a ceramic green. Subsequently, the ceramic green is subjected to a binder removal treatment. The binder removal treatment is performed at 400 ° C. for 12 hours, for example. Subsequently, the ceramic green is fired. Baking is carried out at 1250 ° C. for 4 hours, for example. As a result, a piezoelectric body is obtained.

Next, the piezoelectric body is lap-polished and formed into, for example, a plate having a thickness of 3.2 mm. Subsequently, the 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, or the like to a 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 circumference of the piezoelectric body is ground and slit processing is performed. After that, the conductive paste is baked. The baking process is performed at 800 ° C. for 20 minutes, for example.

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

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

On the second main surface 1b side that is not divided by the slit 5, the divided portions 11 (see FIG. 2) are connected to each other by the connecting portion 12 (see FIG. 2), so that deformation is restricted and it is difficult to deform freely. .. On the other hand, on the side of the first main surface 1a divided by the slit 5, the divided portions 11 are separated from each other, so that they can be easily deformed freely. Therefore, the polarization deformation on the first main surface 1a side is larger than that on the second main surface 1b side. Therefore, the piezoelectric element 1A and the piezoelectric element 100 are curved and deformed so that the first main surface 1a is curved outside and the second main surface 1b is curved inside, and the planar state of the first main surface 1a is the second main surface. It tends to be worse than the flat state of the surface 1b.

When the first main surface 1a in such a flat state is joined to a flat plate-shaped vibrating member (not shown), the joining state between the first main surface 1a and the vibrating member varies within the first main surface 1a. In particular, on the first main surface 1a, the closer the position is to the corner portion A1, the larger the distance between the first main surface 1a and the vibrating member, so that the joint state with the vibrating member tends to deteriorate. As a result of the variation in the bonding state, the transmission of vibration between the piezoelectric element 100 and the vibrating member is reduced.

On the other hand, in the piezoelectric element 1A, the ridge line portion 1e has a chamfered shape. That is, the corner portion A1 has a squared shape. Therefore, 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 that has the largest distance from the vibrating member. As a result, variations in the joint state between the first main surface 1a and the vibrating member are suppressed. Therefore, it is possible to suppress a decrease in vibration transmissibility.

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

In the piezoelectric element 1A, the ridgeline portion between the side surface 1c and the first main surface 1a, the ridgeline portion between the side surface 1d and the first main surface 1a, the ridgeline portion between the side surface 1c and the second main surface 1b, and The ridges between the side surface 1d and the second main surface 1b do not have a chamfered shape. As a result, the reduction of the vibration generation region of the piezoelectric element 1A is suppressed, and a desired vibration amount can be secured.

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

The chamfered shape is not limited to the shape formed by actually chamfering the ridge line portion 1e, and may be a shape equivalent thereto. The ridge line portion 1e is inside a virtual ridge line portion 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 the present embodiment, the chamfered shape of the ridge line portion 1e is a flat shape parallel to the direction D1. The chamfered shape of the ridge line 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 ridge line portion 1e is a rectangular shape having one side on each of the side surface 1c, the side surface 1d, the first main surface 1a, and the second main surface 1b. In the present embodiment, the ridge line portion 1e and the first main surface 1a are not chamfered, but may be chamfered. It can be said that the piezoelectric element 1B has a chamfered portion having a chamfered shape between the side surfaces 1c and the side surfaces 1d adjacent to each other. It can be said that the piezoelectric element 1B substantially has an octagonal columnar shape because the ridge line portion 1e is chamfered.

In the piezoelectric element 1B as well, similarly to the piezoelectric element 1A, the first main surface 1a has a portion corresponding to the portion of the first main surface 1a of the piezoelectric element 100 where the distance from the vibrating member is the largest. Absent. Therefore, it is possible to suppress a decrease in vibration transmissibility.

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

The chamfered shape is not limited to the shape formed by actually chamfering the end portion 1f into a curved surface shape (that is, the corner portion A1 is chamfered into a curved surface shape), and any shape equivalent thereto may be used. The end portion 1f (that is, the corner portion 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 a typical corner and is curved along a virtual 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 be said that the piezoelectric element 1C has a squared portion having a squared shape between the side surface 1c and the side surface 1d adjacent to each other and the first main surface 1a.

In the piezoelectric element 1C as well, similarly to the piezoelectric element 1A, the first main surface 1a has a portion corresponding to the portion of the first main surface 1a of the piezoelectric element 100 where the distance from the vibrating member is the largest. Absent. Therefore, even in the piezoelectric element 1C, it is possible to suppress a decrease in vibration transmissibility with the vibrating member.

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

The chamfered shape is not limited to the shape formed by actually chamfering the ridge line portion 1e into a curved surface, and may be a shape equivalent thereto. The ridge line portion 1e is inside a virtual ridge line portion 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 and curved along a virtual ridge. The ridge line portion 1e smoothly connects the side surface 1c and the side surface 1d to each other. The ridge line portion 1e is a curve that is convex outward when viewed from the direction D1. It can be said that the piezoelectric element 1D has a chamfered portion having a chamfered shape between the side surfaces 1c and the side surfaces 1d adjacent to each other. In the present embodiment, the ridge line portion 1e and the first main surface 1a are not chamfered, but may be chamfered.

In the piezoelectric element 1D as well, similarly to the piezoelectric element 1A, the first main surface 1a has a portion corresponding to the portion of the first main surface 1a of the piezoelectric element 100 where the distance from the vibrating member is the largest. Absent. Therefore, even in the piezoelectric element 1D, it is possible to suppress a decrease in vibration transmissibility with the vibrating member.

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

In the piezoelectric elements 1A, 1B, 1C, and 1D, the ridge line portion between the side surface 1c and the first main surface 1a, the ridge line portion between the side surface 1d and the first main surface 1a, and the side surface 1c and the second main surface 1b. The ridgeline portion of the above 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 ... 1st main surface, 1b ... 2nd main surface, 1e ... Ridge part, 1f ... End part, 5 ... Slit.

Claims (6)

The first and second main surfaces, which have a polygonal shape and face each other,
A piezoelectric element having a plurality of ridges extending in opposite directions of the first main surface and the second main surface.
A slit for dividing the first main surface is provided.
A piezoelectric element in which one of the plurality of ridgeline portions has a chamfered shape at an end portion on the first main surface side. The piezoelectric element according to claim 1, wherein each of the plurality of ridge line portions has the chamfered shape at the end portion on the first main surface side. The piezoelectric element according to claim 1, wherein the one ridge line portion has the chamfered shape over the entire facing direction. The piezoelectric element according to claim 3, wherein the plurality of ridge lines all have the chamfered shape over the entire facing direction. The piezoelectric element according to any one of claims 1 to 4, wherein the chamfered shape is flat. The piezoelectric element according to any one of claims 1 to 4, wherein the chamfered shape is a curved surface.

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