JP6717222B2 - Vibrating device - Google Patents

Description

The present invention relates to a vibrating device.

A piezoelectric element having a first principal surface and a second principal surface facing each other, and a pair of first electrodes arranged on the first principal surface, and a third principal surface facing each other and A vibrating device including a vibrating body having a fourth main surface and having a pair of second electrodes electrically connected to the first electrode is known (for example, Patent Document 1). .. The piezoelectric element and the vibrating body are arranged so that the first main surface and the third main surface face each other. The second electrode is exposed from the piezoelectric element when viewed from the direction orthogonal to the third main surface. In the vibrating device described in Patent Document 1, the vibrating body has a glass plate, and the pair of second electrodes is arranged on the glass plate.

JP-A-04-70100

In the vibrating device described in Patent Document 1, the vibrating body has a glass plate. Therefore, the Q value and strength of the vibrating body are relatively low, and it is difficult to improve the displacement amount.

An object of the present invention is to provide a vibrating device with an improved displacement amount.

A vibrating device according to the present invention, a piezoelectric element having a piezoelectric body having a first main surface and a second main surface facing each other, and a pair of first electrodes arranged on the first main surface, A metal plate having a third main surface and a fourth main surface facing each other, an insulating layer arranged on the third main surface, and a first electrode physically arranged on the insulating layer and corresponding to the first electrode. A vibrating body having a pair of second electrodes that are in contact with each other, and the piezoelectric element and the vibrating body are arranged so that the first main surface and the third main surface face each other with an insulating layer interposed therebetween. The pair of second electrodes are exposed from the piezoelectric element and are separated from all the edges of the insulating layer when viewed from the direction orthogonal to the third main surface.

In the vibrating device according to the present invention, the vibrating body includes a metal plate having a third main surface and a fourth main surface, an insulating layer arranged on the third main surface, and an insulating layer arranged on the insulating layer. A pair of second electrodes that are in physical contact with the corresponding first electrodes. The metal plate has a high Q value and strength as compared with the glass plate. Therefore, the displacement amount of the vibration device is improved.

In the vibrating device according to the present invention, since the second electrode is arranged on the insulating layer, the second electrode and the metal plate are electrically insulated. The second electrode is separated from all the edges of the insulating layer when viewed in the direction orthogonal to the third main surface, and thus is reliably electrically insulated from the metal plate. That is, even when the vibrating body has the metal plate instead of the glass plate, the electrically insulating relationship between the metal plate and the second electrode is secured.

An adhesive member that joins the piezoelectric element and the vibrating body is further provided, and the pair of first electrodes has a plurality of convex portions that are in physical contact with the corresponding second electrodes, and the adhesive member is a plurality of adhesive members. The first electrode and the corresponding second electrode may be bonded to each other while being provided between the convex portions. In this case, the first electrode and the second electrode are joined by the adhesive member provided between the plurality of convex portions. Therefore, the bonding strength between the vibrating body and the piezoelectric element is secured.

The first electrode may be separated from all the edges of the first main surface when viewed from the direction orthogonal to the first main surface. In this case, contact of the first electrode with a conductor included in a device other than the vibration device is suppressed.

The piezoelectric element further has a third electrode arranged on the second main surface, and the third electrode is separated from all edges of the second main surface when viewed from a direction orthogonal to the second main surface. May be In this case, contact of the third electrode with a conductor included in a device other than the vibration device is suppressed.

The piezoelectric body may further have a side surface connecting the first main surface and the second main surface, and the entire second main surface and the side surface may be exposed. In this case, in the piezoelectric element, the electrode (conductor) is not exposed on the surface other than the first main surface facing the vibrating body (third main surface). Therefore, it is possible to prevent the electrode (conductor) included in the piezoelectric element from coming into contact with a conductor included in a device other than the vibration device.

The piezoelectric element includes a plurality of internal electrodes arranged in the piezoelectric body and facing each other, and a conductor arranged in the piezoelectric body and electrically connecting the corresponding internal electrode and the first electrode. , May be further included. In this case, it is not necessary to dispose a conductor for electrically connecting the corresponding internal electrode and the first electrode on the surface of the piezoelectric element. Therefore, it is possible to prevent the electrode (conductor) included in the piezoelectric element from coming into contact with a conductor included in a device other than the vibration device.

According to the present invention, it is possible to provide a vibrating device in which the amount of displacement is improved.

It is a schematic perspective view which shows the vibrating device which concerns on one Embodiment. It is a top view of a piezoelectric element. It is a top view of a piezoelectric element. It is a top view of a vibrating body. It is a figure for demonstrating the cross-sectional structure of a piezoelectric element. It is a figure for demonstrating the state by which the piezoelectric element and the vibrating body were joined. It is a figure for demonstrating the cross-sectional structure of the vibration device which concerns on the modification of this embodiment. It is a figure for demonstrating the cross-sectional structure of the vibration device which concerns on the modification of this embodiment. It is a figure for demonstrating the cross-sectional structure of the vibration device which concerns on the modification of this embodiment. It is a top view which shows the vibrating device which concerns on the further modification of this embodiment. It is a top view which shows the vibrating device which concerns on the further modification of this embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description, the same elements or elements having the same function will be denoted by the same reference symbols, without redundant description.

First, the configuration of the vibrating device according to the present embodiment will be described with reference to FIGS. 1 to 5. FIG. 1 is a schematic perspective view showing a vibrating device according to this embodiment. 2 and 3 are plan views of the piezoelectric element. FIG. 4 is a plan view of the vibrating body. FIG. 5 is a diagram for explaining the cross-sectional structure of the piezoelectric element.

As shown in FIG. 1, the vibrating device 1 includes a piezoelectric element 10, a vibrating body 20, and an adhesive member 30 that joins the piezoelectric element 10 and the vibrating body 20.

The piezoelectric element 10 includes a piezoelectric element 11, a pair of first electrodes 12 and 13, internal electrodes 17a, 17b, 18a and 18b, pad conductors 7a, 7b, 8a and 8b, a third electrode 14, and a via. And a conductor 19. The piezoelectric element 10 has a laminated structure. Any one of the pair of first electrodes 12 and 13, the plurality of internal electrodes 17a, 17b, 18a and 18b, and the third electrode 14 and the piezoelectric layer of the piezoelectric body 11 are alternately arranged.

The piezoelectric body 11 has a rectangular parallelepiped shape. The piezoelectric body 11 has a first main surface 11a and a second main surface 11b facing each other, and four side surfaces 11c. The first major surface 11a has a rectangular shape and has four edges 15a, 15b, 15c, 15d. Each side surface 11c extends in a direction in which the first main surface 11a and the second main surface 11b face each other so as to connect the first main surface 11a and the second main surface 11b. The rectangular parallelepiped shape also includes a rectangular parallelepiped shape with chamfered corners and ridges, and a rectangular parallelepiped shape with rounded corners and ridges. The shape of the piezoelectric body 11 is not limited to a rectangular parallelepiped shape, and may be, for example, a disk shape.

The direction in which the first main surface 11a and the second main surface 11b face each other is the thickness direction of the piezoelectric element body 11. The direction in which the pair of side surfaces 11c face each other is the longitudinal direction of the piezoelectric body 11, and the direction in which the other pair of side surfaces 11c faces each other is the width direction of the piezoelectric body 11. The length of the piezoelectric body 11 in the longitudinal direction is, for example, 50 mm. The length of the piezoelectric body 11 in the width direction is, for example, 50 mm. The length of the piezoelectric body 11 in the thickness direction is, for example, 0.1 mm.

The piezoelectric body 11 is configured such that a plurality of piezoelectric layers are laminated in a direction in which the first main surface 11a and the second main surface 11b face each other. In this embodiment, the direction in which the plurality of piezoelectric layers are stacked coincides with the direction in which the first main surface 11a and the second main surface 11b face each other. The piezoelectric body 11 is made of a piezoelectric ceramic material. Examples of the piezoelectric ceramic material include PZT [Pb(Zr,Ti)O ₃ ], PT(PbTiO ₃ ), PLZT[(Pb,La)(Zr,Ti)O ₃ ], and barium titanate (BaTiO ₃ ). Can be mentioned. Each piezoelectric layer is made of, for example, a sintered body of a ceramic green sheet containing the above-mentioned piezoelectric ceramic material. In the actual piezoelectric element body 11, the respective piezoelectric layers are integrated so that the boundaries between the respective piezoelectric layers cannot be recognized.

As shown in FIGS. 2 and 5, a pair of first electrodes 12 and 13 are arranged on the first main surface 11 a of the piezoelectric body 11. As shown in FIGS. 1, 3, and 5, the third electrode 14 is disposed on the second main surface 11b of the piezoelectric body 11. As shown in FIG. 5, inside the piezoelectric body 11, a plurality of internal electrodes 17a, 18a, 17b, 18b facing each other are arranged. As shown in FIGS. 1 and 5, no electrode is provided on the side surface 11c of the piezoelectric body 11, and the entire side surface 11c is exposed. Here, the entire side surface 11c refers to the entire area between the first main surface 11a and the second main surface 11b over the entire circumference of the side surface 11c.

The first electrodes 12, 13, the internal electrodes 17a, 17b, 18a, 18b, the pad conductors 7a, 7b, 8a, 8b, and the third electrode 14 are made of a conductive material (for example, Ag, Pd, or Cu). , Both are conductors. These conductors are configured as a sintered body of a conductive paste containing a conductive material.

As shown in FIG. 2, the pair of first electrodes 12 and 13 is viewed from a direction orthogonal to the first major surface 11a (the direction in which the first major surface 11a and the second major surface 11b face each other). , All the edges 15a, 15b, 15c, 15d of the first main surface 11a, that is, the side surface 11c. In the present embodiment, the separation distance between the edges of the pair of first electrodes 12 and 13 and the edges 15a, 15b, 15c, and 15d of the first principal surface 11a when viewed from the direction orthogonal to the first principal surface 11a is It is 20 μm or more.

The first electrode 12 has a circular shape when viewed from a direction orthogonal to the first main surface 11a, and is arranged closer to the corner defined by the edges 15a and 15b of the first main surface 11a than the first electrode 13. Has been done. The first electrode 12 does not necessarily have to be arranged near the corner of the first major surface 11a. For example, the first electrode 12 may be arranged near one of the edges 15a, 15b, 15c, 15d of the first major surface 11a.

The first electrode 13 is separated from the first electrode 12 on the first major surface 11a, and has a rectangular shape when viewed from a direction orthogonal to the first major surface 11a. This rectangular shape also includes, for example, a shape with rounded corners. The first electrode 13 has a shape in which the arrangement area of the first electrode 12 is excluded from the rectangular shape. That is, the first electrode 13 includes the arrangement area of the first electrode 12 on the first main surface 11a, and all the edges 15a, 15b, 15c, 15d of the pair of first electrodes 12 and 13 and the first main surface 11a. It is located on an area other than the area separated from.

The internal electrodes 17a and 17b are electrically connected to each other by the pad conductors 7a and 7b and the via conductor 19. The internal electrodes 18a and 18b are electrically connected to each other by the pad conductors 8a and 8b and the via conductor 19.

The internal electrodes 17a, 17b and the pad conductors 7a, 7b are arranged so as to face each other with the piezoelectric layer interposed therebetween, and the internal electrodes 17a, the pads are arranged in the direction from the first main surface 11a to the second main surface 11b. The conductor 7a, the internal electrode 17b, and the pad conductor 7b are arranged in this order. The internal electrodes 18a, 18b and the pad conductors 8a, 8b are arranged so as to face each other via the piezoelectric layer, and in the direction from the first main surface 11a to the second main surface 11b, the pad conductors 8a, The electrode 18a, the pad conductor 8b, and the internal electrode 18b are arranged in this order. The first main surface 11a and the second main surface 11b of the internal electrode 17a and the pad conductor 8a, the pad conductor 7a and the internal electrode 18a, the internal electrode 17b and the pad conductor 8b, and the pad conductor 7b and the internal electrode 18b face each other. In the direction, they are located on the same layer and are separated from each other on the same layer.

The internal electrodes 17a, 17b, 18a, 18b and the pad conductors 7a, 7b, 8a, 8b are separated from the side surface 11c. In the present embodiment, the distance between the edges of the internal electrodes 17a, 17b, 18a, 18b and the pad conductors 7a, 7b, 8a, 8b and the side surface 11c is 10 μm or more when viewed from the direction orthogonal to the first major surface 11a. Is.

The pad conductors 7a, 7b, 8a, 8b have a circular shape when viewed from the direction orthogonal to the first major surface 11a. That is, the pad conductors 7a, 7b, 8a, 8b have substantially the same shape as the first electrode 12.

The pad conductors 7a and 7b are arranged in the vicinity of a corner defined by a pair of side surfaces 11c adjacent to each other so as to overlap the first electrode 12 when viewed in a direction orthogonal to the first major surface 11a. The pad conductors 8a and 8b are arranged in the vicinity of a corner different from the corner where the pad conductors 7a and 7b are located when viewed from the direction orthogonal to the first major surface 11a. The pad conductors 7a, 7b, 8a, 8b do not necessarily have to be arranged in the vicinity of the corner defined by the pair of adjacent side surfaces 11c. For example, the pad conductors 7a, 7b, 8a, 8b may be arranged near one of the four side surfaces 11c.

The internal electrodes 17a, 17b, 18a, 18b have a rectangular shape when viewed from a direction orthogonal to the first major surface 11a. This rectangular shape also includes, for example, a shape with rounded corners. The internal electrodes 17a, 17b, 18a, 18b have substantially the same shape as the first electrode 13.

As shown in FIG. 3, the third electrode 14 is separated from all the edges 16a, 16b, 16c, 16d of the second main surface 11b, that is, the side surface 11c when viewed from the direction orthogonal to the second main surface 11b. ing. In the present embodiment, the separation distance between the edge of the third electrode 14 and each edge 16a, 16b, 16c, 16d of the second main surface 11b when viewed from the direction orthogonal to the second main surface 11b is 20 μm or more. .. The third electrode 14 has a rectangular shape when viewed from a direction orthogonal to the first major surface 11a. This rectangular shape also includes, for example, a shape with rounded corners.

The first electrode 13, the internal electrodes 17a, 17b, 18a, 18b, and the third electrode 14 have regions overlapping each other when viewed in the direction orthogonal to the first main surface.

The via conductor 19 is provided inside the piezoelectric body 11 and in the vicinity of the side surface 11c when viewed from the direction orthogonal to the first main surface 11a. The via conductor 19 includes conductors (inner electrodes 17a, 17b, 18a, 18b, pad conductors 7a, 7b, 8a, 8b, first conductors) that are adjacent to each other in the direction in which the first main surface 11a and the second main surface 11b face each other. The electrodes 12, 13) are connected physically and electrically. The via conductor 19 penetrates the piezoelectric layer located between the conductors adjacent to each other in the direction in which the first main surface 11a and the second main surface 11b face each other. The first electrode 12, the internal electrode 17a, the pad conductor 7a, the internal electrode 17b, the pad conductor 7b, and the third electrode 14 are electrically connected through the via conductor 19. The first electrode 13, the pad conductor 8a, the internal electrode 18a, the pad conductor 8b, and the internal electrode 18b are electrically connected through the via conductor 19.

In the present embodiment, the pair of via conductors 19 connect the conductors adjacent to each other in the direction in which the first main surface 11a and the second main surface 11b face each other. The connection of the conductors adjacent to each other in the direction in which the first main surface 11a and the second main surface 11b face each other may be realized by one via conductor 19 or by three or more via conductors 19. May be The via conductor 19 is located in a region overlapping the corresponding pad conductors 7a, 7b, 8a, 8b when viewed from the direction orthogonal to the first major surface 11a.

The vibrating body 20 includes a metal plate 21, an insulating layer 22 arranged on the metal plate 21, and a pair of second electrodes 23, 24 arranged on the insulating layer 22. The vibrating body 20 is arranged so that the metal plate 21 and the piezoelectric body 11 face each other with the insulating layer 22 in between. The vibrating body 20 and the piezoelectric element 10 are joined by an adhesive member 30. The vibrating body 20 has a rectangular shape when viewed from a direction orthogonal to the first major surface 11a. The rectangular shape also includes, for example, a shape with rounded corners. The shape of the vibrating body 20 is not limited to the rectangular shape.

The metal plate 21 has a rectangular shape when viewed from a direction orthogonal to the first main surface 11a, and has a third main surface 21a and a fourth main surface 21b facing each other. This rectangular shape also includes, for example, a shape with rounded corners. Examples of the material of the metal plate 21 include Ni, stainless steel, brass, invar and the like. The dimensions of the third major surface 21a of the metal plate 21 are, for example, 80 mm×90 mm. The area of the third major surface 21a is at least larger than the area of the first major surface 11a of the piezoelectric element 10.

The insulating layer 22 is arranged on the third major surface 21 a of the metal plate 21. Examples of the material of the insulating layer 22 include polyimide resin and epoxy resin. The thickness of the insulating layer 22 is, for example, 5 μm. The insulating layer 22 covers the third major surface 21 a of the metal plate 21. In the present embodiment, the insulating layer 22 covers the entire third major surface 21a.

As shown in FIG. 4, the pair of second electrodes 23, 24 extends from the central portion of the vibrating body 20 toward the edge 22a of the third main surface 21a when viewed from the direction orthogonal to the first main surface 11a. It has an existing line shape. One end of each second electrode 23, 24 is located in the central portion of the vibrating body 20, and the other end of each second electrode 23, 24 is located near the edge 22a and away from the edge 22a. doing. The second electrode 23 and the second electrode 24 are separated from each other on the third major surface 21a. The pair of second electrodes 23 and 24 are exposed from the piezoelectric element 10 when viewed from the direction orthogonal to the third major surface 21a. The pair of second electrodes 23, 24 are separated from not only the edge 22a but also the three edges 22b, 22c, 22d of the insulating layer 22 when viewed from the direction orthogonal to the third major surface 21a.

In the present embodiment, the separation distance between the other ends of the pair of second electrodes 23 and 24 and the edge 22a of the insulating layer 22 is 5 μm or more when viewed in the direction orthogonal to the third major surface 21a. The second electrodes 23 and 24 are not limited to linear shapes. The second electrodes 23 and 24 are made of, for example, Au, Sn, Ni or the like.

The pair of second electrodes 23, 24 are in physical contact with the corresponding first electrodes 12, 13 as shown in FIG. The pair of first electrodes 12 and 13 has a plurality of convex portions A on the surface side facing the vibrating body 20 (second electrodes 23 and 24 ). The convex portion A of the first electrode 12 physically contacts the second electrode 23, and the convex portion A of the first electrode 13 physically contacts the second electrode 24. The surface of the second electrode 23 that contacts the first electrode 12 is flatter than the surface of the first electrode 12 that faces the vibrating body 20. The surface of the second electrode 24 that contacts the first electrode 13 is also flat compared to the surface of the first electrode 13 that faces the vibrating body 20.

As shown in FIG. 6, the adhesive member 30 is provided between the plurality of convex portions A, and joins the corresponding first electrodes 12 and 13 and the corresponding second electrodes 23 and 24. The first electrode 12 and the second electrode 23 are joined by the adhesive member 30, and the first electrode 13 and the second electrode 24 are joined by the adhesive member 30.

In the present embodiment, as shown in FIG. 5, the adhesive member 30 joins the insulating layer 22 and the first main surface 11a, and also joins a part of the side surface 11c and the insulating layer 22. .. An epoxy resin, an acrylic resin, or the like is used for the adhesive member 30. The adhesive member 30 does not contain a conductive filler.

Next, the operation and effect of the vibrating device 1 will be described.

As described above, in the piezoelectric element 10, the first electrode 13, the internal electrodes 17a, 17b, 18a, 18b, and the third electrode 14 have a region where they overlap with each other when viewed from the direction orthogonal to the first main surface. Have The internal electrodes 17a and 17b and the third electrode 14 are electrically connected to the first electrode 12 by the via conductor 19 and the pad conductors 7a and 7b. The internal electrodes 18a and 18b and the third electrode 14 are electrically connected to the first electrode 13 by the via conductor 19 and the pad conductors 8a and 8b.

For example, when voltages having different polarities are applied to the first electrode 12 and the first electrode 13, the first electrode 13, the internal electrode 17a, the internal electrode 18a, the internal electrode 17b, the internal electrode 18b, and the third electrode 14 are applied. An electric field is generated. Therefore, in the piezoelectric body 11, a region sandwiched between the first electrode 13 and the internal electrode 17a, a region sandwiched between the internal electrode 17a and the internal electrode 18a, a region sandwiched between the internal electrode 18a and the internal electrode 17b. The region sandwiched between the internal electrode 17b and the internal electrode 18b and the region sandwiched between the internal electrode 18b and the third electrode 14 become active regions, and displacement occurs in the active regions. That is, when the AC voltage is applied to the pair of first electrodes 12 and 13, the piezoelectric element 10 repeats expansion and contraction according to the frequency of the applied AC voltage.

The piezoelectric element 10 and the vibrating body 20 are arranged so that the first main surface 11a and the third main surface 21a face each other with the insulating layer 22 in between, and are bonded to each other by the adhesive member 30. Therefore, the vibrating body 20 flexurally vibrates integrally with the piezoelectric element 10 in response to repeated expansion and contraction of the piezoelectric element 10. At this time, the displacement amount of the vibrating body 20 is improved as the Q value and the strength of the vibrating body 20 are higher.

In the vibrating device 1, the vibrating body 20 has a metal plate 21. The vibrating body 20 having the metal plate 21 has a high Q value and strength as compared with a vibrating body having a glass plate instead of the metal plate 21. Therefore, the displacement amount of the vibration device 1 is improved.

In the vibrating device 1, since the second electrodes 23 and 24 are arranged on the insulating layer 22, the second electrodes 23 and 24 and the metal plate 21 are electrically insulated. The second electrodes 23, 24 are separated from all the edges 22a, 22b, 22c, 22d of the insulating layer 22 when viewed from the direction orthogonal to the third major surface 21a, so that the second electrodes 23, 24 are reliably electrically connected to the metal plate 21. Insulated. That is, even when the vibrating body 20 has the metal plate 21 instead of the glass plate, the electrically insulating relationship between the metal plate 21 and the second electrodes 23 and 24 is secured.

The first electrodes 12 and 13 and the second electrodes 23 and 24 are joined by an adhesive member 30 provided between the plurality of convex portions A. Therefore, the bonding strength between the vibrating body 20 and the piezoelectric element 10 is secured. In the present embodiment, the insulating layer 22 and the first main surface 11a are joined by the adhesive member 30, and part of the side surface 11c and the insulating layer 22 are joined by the adhesive member 30. Therefore, the bonding strength between the vibrating body 20 and the piezoelectric element 10 is further increased.

The first electrodes 12 and 13 are separated from all the edges 15a, 15b, 15c, and 15d of the first principal surface 11a when viewed from the direction orthogonal to the first principal surface 11a. For this reason, the first electrodes 12 and 13 are not exposed on the surface of the vibrating device 1, and the first electrodes 12 and 13 are suppressed from coming into contact with conductors provided in equipment other than the vibrating device 1.

The piezoelectric element 10 further has a third electrode 14 arranged on the second major surface 11b, and the third electrode 14 has a third major surface 11b of the second major surface 11b when viewed from a direction orthogonal to the second major surface 11b. It is separated from all the edges 16a, 16b, 16c, 16d. For this reason, the third electrode 14 is suppressed from coming into contact with a conductor provided in a device other than the vibrating device 1.

The piezoelectric element 10 has a via conductor 19 which is arranged in the piezoelectric element body 11 and electrically connects the corresponding internal electrodes 17a, 17b, 18a, 18b and the first electrodes 12, 13. Therefore, it is not necessary to dispose a conductor for electrically connecting the corresponding corresponding internal electrodes 17a, 17b, 18a, 18b and the first electrodes 12, 13 on the surface of the piezoelectric element 10. Therefore, it is possible to prevent the conductors (the internal electrodes 17a, 17b, 18a, 18b and the pad conductors 7a, 7b, 8a, 8b) of the piezoelectric element 10 from coming into contact with conductors provided in equipment other than the vibration device 1. Has been done.

The adhesive member 30 does not contain a conductive filler. The electrical connection between the first electrodes 12 and 13 and the second electrodes 23 and 24 is established only by the physical contact between the first electrodes 12 and 13 and the second electrodes 23 and 24. The adhesive member 30 does not contribute to the electrical connection between the first electrodes 12 and 13 and the second electrodes 23 and 24. The adhesive member 30 has more resin components contained in the same volume and higher adhesive strength than an adhesive member containing a conductive filler. Therefore, the bonding strength between the vibrating body 20 and the piezoelectric element 10 is increased.

Next, the configuration of the vibrating device 1 according to the modified example of the present embodiment will be described with reference to FIGS. 7 to 9. 7 to 9 are diagrams for explaining a cross-sectional configuration according to a modified example of the vibration device 1.

First, the configuration of the modification shown in FIG. 7 will be described. In this modification, the piezoelectric element 10 does not have the third electrode 14 that the piezoelectric element 10 shown in FIG. 5 has. The piezoelectric element 10 of this modified example has internal electrodes 17a, 17b, 17c, 18a, 18b, pad conductors 7a, 7b, 8a, 8b, first electrodes 12, 13, and via conductors 19 as conductors. .. In the piezoelectric element 10 of this modification, in addition to the side surface 11c, the entire second main surface 11b is exposed. Therefore, in the piezoelectric body 11 of this modification, the electrodes (conductors) are not exposed on the surface other than the first main surface 11a facing the vibrating body 20 (third main surface 21a). Therefore, the conductors (the internal electrodes 17a, 17b, 17c, 18a, 18b, and the pad conductors 7a, 7b, 8a, 8b) of the piezoelectric element 10 should come into contact with the conductors provided in equipment other than the vibration device 1. Is suppressed.

Next, the configuration of the modification shown in FIG. 8 will be described. In this modification, the piezoelectric element 10 does not have an internal electrode. The piezoelectric element 10 of this modification has only the first electrodes 12 and 13, the third electrode 14, and the via conductor 19 as conductors. The third electrode 14 is electrically connected to the first electrode 12 through one via conductor 19. The first electrode 13 and the third electrode 14 have regions overlapping each other when viewed from the direction orthogonal to the first major surface 11a.

For example, in the present modification, when voltages having different polarities are applied to the first electrode 12 and the first electrode 13 in the piezoelectric element 10, an electric field is generated between the first electrode 13 and the third electrode 14. Therefore, the region of the piezoelectric body 11 sandwiched between the first electrode 13 and the third electrode 14 becomes an active region, and displacement occurs in the active region. That is, also in this modification, the piezoelectric element 10 repeats expansion and contraction according to the frequency of the applied AC voltage when the AC voltage is applied to the pair of first electrodes 12 and 13.

Next, the configuration of the modification shown in FIG. 9 will be described. In the present modification, the piezoelectric element 10 has the first electrodes 12 and 13, the internal electrodes 17a, the internal electrodes 18a and 18b, and the via conductors 19 as conductors. The first electrode 12 is electrically connected to the internal electrode 17a through one via conductor 19. The first electrode 13 is electrically connected to the internal electrodes 18a and 18b through one via conductor 19. The internal electrode 18b is located inside the piezoelectric body 11. That is, in the piezoelectric body 11, the entire second main surface 11b is exposed in addition to the side surface 11c. Since the conductors (internal electrodes 17a, 18a, 18b) included in the piezoelectric element 10 are not exposed on the surface of the vibrating device 1, the conductors (internal electrodes 17a, 18a, 18b) are devices other than the vibrating device 1. The contact with the conductor included in is suppressed.

In this modification, the area of the first electrode 13 is small, and the first electrode 13 does not overlap the internal electrode 17a when viewed from the direction orthogonal to the first major surface 11a. Therefore, in the piezoelectric element 10 of the present modification, displacement is generated mainly by the electric field generated between the internal electrodes 17a, 18a, 18b.

Next, with reference to FIG. 10, a vibrating device 1A according to a further modification of the present embodiment will be described. FIG. 10 is a plan view showing a vibrating device according to this modification.

As in the vibration device 1 described above, the vibration device 1A according to the present modification includes a piezoelectric element 10, a vibration body 20, a piezoelectric element 10, and a vibration body 20 as shown in FIG. And an adhesive member 30 (not shown) joining the two. As shown in FIG. 10, in the vibrating device 1A, the shapes of the piezoelectric element 10, the metal plate 21, the insulating layer 22, and the second electrodes 23 and 24 are different from those of the vibrating device 1 described above.

In the piezoelectric element 10 of this modification, for example, the length of the piezoelectric element body 11 in the longitudinal direction is 20 mm, and the length of the piezoelectric element body 11 in the width direction is 10 mm. The separation distance between the edge of the third electrode 14 and the edges 16a, 16b, 16c, 16d of the second principal surface 11b is 20 μm or more, as in the first embodiment.

The metal plate 21 has a circular shape when viewed from a direction orthogonal to the second main surface 11b. The size of the metal plate 21 is, for example, 30 mm in diameter. The piezoelectric element 10 is provided in the center of the metal plate 21 via the insulating layer 22 as viewed in the direction orthogonal to the second main surface 11b.

The second electrode 24 includes a linear electrode portion 24a that linearly extends from the central portion of the vibrating body 20 toward the edge, and an annular electrode portion that annularly extends along the edge of the vibrating body 20. 24b and. One end of the linear electrode portion 24a is electrically connected to the piezoelectric element 10, and the other end is connected to the inner circumference of the annular electrode portion 24b. The annular electrode portion 24b is located apart from the edge of the vibrating body 20. The separation distance between the outer periphery of the annular electrode portion 24b and the edge of the vibrating body 20 is 5 μm or more, as in the first embodiment.

The second electrode 23 has a linear electrode portion 23a extending linearly from the central portion of the vibrating body 20 toward the edge and parallel to the linear electrode portion 24a, and an inner circumference of the annular electrode portion 24b. And an annular electrode portion 23b extending in an annular shape along the. One end of the linear electrode portion 23a is electrically connected to the piezoelectric element 10, and the other end is connected to the inner circumference of the annular electrode portion 23b. The second electrode 23 and the second electrode 24 are separated from each other. The distance between the outer circumference of the annular electrode portion 23b and the inner circumference of the annular electrode portion 24b is 500 μm or more.

The ring-shaped electrode portion 23b has a partially cut ring shape and includes end portions 25a and 25b. The end 25a and the end 25b face each other with the linear electrode portion 24a interposed therebetween. That is, the linear electrode portion 24a extends between the end portion 25a and the end portion 25b, extends to the edge of the metal plate 21, and is connected to the inner circumference of the annular electrode portion 24b. The annular electrode portion 23b is separated from the piezoelectric element 10.

Next, with reference to FIG. 11, a vibrating device 1B according to a further modification of the present embodiment will be described. FIG. 11 is a plan view showing a vibrating device according to this modification.

As shown in FIG. 11, the vibrating device 1B according to this modification and the vibrating device 1 described above are different in the number of piezoelectric elements 10 arranged on the vibrating body 20. The vibration device 1B includes a plurality of piezoelectric elements 10, a vibrating body 20, and an adhesive member 30 (not shown) that joins the piezoelectric elements 10 and the vibrating body 20.

In the piezoelectric element 10 shown in FIG. 11, for example, the length of the piezoelectric element body 11 in the longitudinal direction is 30 mm, and the length of the piezoelectric element body 11 in the width direction is 30 mm. The separation distance between the edge of the third electrode 14 and the edges 16a, 16b, 16c, 16d of the second principal surface 11b is 20 μm or more, as in the first embodiment.

The metal plate 21 has a rectangular shape when viewed from a direction orthogonal to the second major surface 11a. This rectangular shape also includes, for example, a shape with rounded corners. The dimensions of the third major surface 21a of the metal plate 21 are, for example, 1600 mm×1200 mm.

In this embodiment, 12 piezoelectric elements 10 are arranged in a matrix with respect to one vibrating body 20. Ten piezoelectric elements 10 are arranged along the edge of the vibrating body 20, and two piezoelectric elements 10 are arranged at the center of the vibrating body 20. That is, the piezoelectric element 10 arranged in the center of the vibrating body 20 is surrounded by the piezoelectric elements 10 arranged along the edges of the vibrating body 20.

As shown in FIG. 11, a pair of second electrodes 23 and 24 is provided for each piezoelectric element 10. Both the second electrodes 23 and 24 extend toward the edge of the vibrating body 20. More specifically, each of the second electrodes 23 and 24 has one end electrically connected to the corresponding piezoelectric element 10 and the other end provided near the edge of the vibrating body 20 and separated from the edge of the vibrating body 20. doing.

The linear second electrodes 23 and 24 are electrically connected to the piezoelectric element 10 arranged along the edge of the vibrating body 20. L-shaped second electrodes 23 and 24 are electrically connected to the piezoelectric element 10 arranged in the center of the vibrating body 20. The L-shaped second electrodes 23 and 24 are linear electrode portions 23c and 24c extending toward the long side of the metal plate 21 and linear electrode portions extending toward the short side of the metal plate 21, respectively. It has parts 23d and 24d.

The linear electrode portions 23c and 24c have one end electrically connected to the piezoelectric element 10 and the other end connected to the linear electrode portions 23d and 24d. One end of each of the linear electrode portions 23d and 24d is connected to the linear electrode portions 23c and 24c, and the other end thereof extends toward the edge of the vibrating body 20.

In the vibrating device 1B according to the modified example shown in FIG. 11, the intervals between the second electrodes 23 and 24 are made sparse according to the position of each piezoelectric element 10 with respect to each side of the edge of the vibrating body 20. The second electrodes 23 and 24 extend toward different four sides. For example, in the piezoelectric element 10 arranged along the edge of the vibrating body 20, the second electrodes 23 and 24 connected to the piezoelectric element 10 extend toward the side of the closest edge. All of the second electrode 23 and the second electrode 24 provided on the vibrating body 20 may extend toward one side of the edge of the vibrating body 20.

The second electrode 23 and the second electrode 24 may extend toward different sides of the edge of the vibrating body 20. In this case, the second electrode 23 and the second electrode 24 may extend toward the opposite sides of the edge of the vibrating body 20. The second electrodes 23 of all the piezoelectric elements 10 extend toward one side of the edge of the vibrating body 20, and the second electrodes 24 of all the piezoelectric elements 10 are located in the direction in which the second electrodes 23 extend. It may extend toward one side different from the side.

Although the preferred embodiments of the present invention 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 scope of the invention.

The number of internal electrodes 17a, 17b, 17c, 18a, 18b arranged in the piezoelectric element 10 is not limited to the number shown in the above-described embodiment and modification.

In the present embodiment, the internal electrodes 17a, 17b, 17c, 18a, 18b that generate an electric field, the first electrodes 12 and 13, and the third electrode 14 have a rectangular shape, but are not limited thereto. For example, the internal electrodes 17a, 17b, 17c, 18a, 18b, the first electrodes 12, 13 and the third electrode 14 may have a circular shape or the like when viewed from the direction orthogonal to the first major surface 11a. ..

The insulating layer 22 does not necessarily have to cover the entire third major surface 21a of the metal plate 21. If the second electrodes 23 and 24 and the metal plate 21 are electrically insulated, the insulating layer 22 may not cover the entire third major surface 21a. That is, a part of the third major surface 21 a of the metal plate 21 may be exposed from the insulating layer 22. Even in this case, the pair of second electrodes 23 and 24 are separated from all the edges of the insulating layer 22.

Although the first electrodes 12 and 13 of the piezoelectric element 10 have the convex portions A, the second electrodes 23 and 24 of the vibrating body 20 may have the convex portions.

The adhesive member 30 may include a conductive filler. In this case, the first electrode 12 and the second electrode 23 are electrically connected more reliably, and the first electrode 13 and the second electrode 24 are electrically connected more reliably. In the present embodiment, the insulating layer 22 and the first main surface 11a are joined by the adhesive member 30, and part of the side surface 11c and the insulating layer 22 are joined by the adhesive member 30. Does not need to be bonded to the first main surface 11a, and it is not necessary for a part of the side surface 11c and the insulating layer 22 to be bonded.

1, 1A, 1B... Vibrating device, 10... Piezoelectric element, 11... Piezoelectric element, 11a... First principal surface, 11b... Second principal surface, 12, 13... First electrode, 20... Vibrating body, 21... Metal Plate, 21a... Third main surface, 21b... Fourth main surface, 22... Insulating layer, 22a, 22b, 22c, 22d... Edge of insulating layer.

Claims (10)

A piezoelectric element having a piezoelectric body having a first main surface and a second main surface facing each other, and a pair of first electrodes arranged on the first main surface,
A metal plate having a third main surface and a fourth main surface facing each other, an insulating layer arranged on the third main surface, and a corresponding first electrode arranged on the insulating layer A pair of second electrodes that are in physical contact, and a vibrating body having,
The piezoelectric element and the vibrating body are arranged so that the first main surface and the third main surface are opposed to each other via the insulating layer,
The vibrating device in which the pair of second electrodes are exposed from the piezoelectric element and are separated from all edges of the insulating layer when viewed in a direction orthogonal to the third main surface. Further comprising an adhesive member joining the piezoelectric element and the vibrating body,
The pair of first electrodes has a plurality of convex portions that are in physical contact with the corresponding second electrodes,
The vibrating device according to claim 1, wherein the adhesive member is provided between the plurality of convex portions, and joins the corresponding first electrode and the corresponding second electrode. The vibrating device according to claim 2, wherein the adhesive member is made of resin and is continuously provided from one of the pair of second electrodes to the other. The vibrating device according to claim 1, wherein the first electrode is separated from all edges of the first main surface when viewed from a direction orthogonal to the first main surface. The piezoelectric element further has a third electrode arranged on the second main surface,
Said third electrode, said when viewed from the direction perpendicular to the second major surface is spaced from all edges of the second main surface, the vibration device according to any one of claims 1-4. The piezoelectric element further has a side surface connecting the first main surface and the second main surface,
It said second main surface and the whole of the side surface is exposed, the vibration device according to any one of claims 1-4. The piezoelectric element is
A plurality of internal electrodes arranged in the piezoelectric body and facing each other,
Wherein arranged in the piezoelectric element assembly, and the corresponding conductor connecting said internal electrode and the first electrode electrically further comprises a according to any one of claims 1 to 6 Vibrating device. The insulating layer comprises at least one of polyimide resin and epoxy resin, the vibration device according to any one of claims 1-7. The insulating layer covers up to the edge of the third main surface of the metal plate,
The pair of second electrodes extend toward the edge of the third main surface, the vibration device according to any one of claims 1-8. The insulating layer covers the entirety of the third main surface of the metal plate, the vibration device according to any one of claims 1-9.

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