JP7087942B2 - Vibration devices, electronic devices, and how to drive vibration devices - Google Patents

Description

One aspect of the present invention relates to a vibrating device, an electronic device, and a method of driving the vibrating device.

Patent Document 1 describes a piezoelectric actuator including a piezoelectric element and a flexible substrate bonded to one main surface of the piezoelectric element. On one main surface of the piezoelectric element, the flatness of the region to which the flexible substrate is joined is lower than the flatness of the other main surface of the piezoelectric element. Therefore, peeling of the flexible substrate can be suppressed as compared with the case where the flexible substrate is bonded to the region where the flatness of the piezoelectric element is high.

Japanese Patent No. 5474261

The piezoelectric actuator described in Patent Document 1 cannot suppress reverberation.

One aspect of the present invention provides a vibrating device, an electronic device, and a method for driving the vibrating device capable of suppressing reverberation.

The vibration device according to one aspect of the present invention is a piezoelectric element having a piezoelectric element having a rectangular main surface, an external electrode arranged on the main surface, and an external electrode. It comprises a wiring member located above and electrically connected to an external electrode, the wiring member having a rectangular first surface that overlaps the main surface when viewed from an orthogonal direction orthogonal to the main surface. It has a region, the first region includes a second region bonded to the piezoelectric element so as to cover the external electrode, and the second region is one corner of the first region when viewed from an orthogonal direction. It is located closer to the department.

In one aspect described above, the wiring member has a first region that overlaps the main surface when viewed from an orthogonal direction orthogonal to the main surface of the piezoelectric element. The first region includes a second region bonded to the piezoelectric element so as to integrally cover the plurality of external electrodes of the piezoelectric element. The second region is unevenly arranged near the corner of any one of the rectangular first regions. That is, the arrangement of the regions other than the second region in the first region is biased around the second region. As a result, the resonance points of the regions other than the second region of the first region are shifted. As a result, reverberation can be suppressed.

In one of the above aspects, a piezoelectric element having a piezoelectric element having a rectangular main surface, an external electrode arranged on the main surface, and a piezoelectric element located on the external electrode and The wiring member comprises a wiring member that is electrically connected to an external electrode, and the wiring member has a first region that overlaps the main surface when viewed from an orthogonal direction orthogonal to the main surface, and the first region is A second region joined to the piezoelectric element so as to cover the external electrode is included, and one end in the short side direction of the main surface of the first region and one end in the short side direction of the second region when viewed from the orthogonal direction. The first length between and is different from the second length between the other end in the short side direction of the first region and the other end in the short side direction of the second region, and is the length of the main surface of the first region. The third length between one end in the side direction and one end in the long side direction of the second region is between the other end in the long side direction of the first region and the other end in the long side direction of the second region. It is different from the fourth length of.

In one aspect described above, the wiring member has a first region that overlaps the main surface when viewed from an orthogonal direction orthogonal to the main surface of the piezoelectric element. The first region includes a second region bonded to the piezoelectric element so as to integrally cover the plurality of external electrodes of the piezoelectric element. Seen from the orthogonal direction, the first length is different from the second length and the third length is different from the fourth length. That is, the arrangement of the regions other than the second region in the first region is biased around the second region. As a result, the resonance points of the regions other than the second region of the first region are shifted. As a result, reverberation can be suppressed.

In one aspect described above, the wiring member may extend along the long side of the main surface so as to intersect the short side of the main surface when viewed from the orthogonal direction. In this case, it is possible to suppress the wiring member from inhibiting the vibration of the piezoelectric element as compared with the case where the wiring member extends along the short side of the main surface so as to intersect the long side of the main surface. Become.

In one aspect described above, the second region may cover the entire external electrode when viewed from the orthogonal direction. In this case, since the plurality of external electrodes are not exposed from the second region, the occurrence of a short circuit can be suppressed.

In one aspect described above, the second region may be arranged in the central portion of the main surface when viewed from the orthogonal direction. In this case, a plurality of external electrodes are also arranged in the central portion of the main surface. Therefore, the piezoelectric element can be vibrated in a well-balanced manner.

In one of the above embodiments, a vibrating member bonded to the piezoelectric element may be further provided. In this case, vibration can be increased.

The electronic device according to one aspect of the present invention includes the above-mentioned vibration device.

In one of the above embodiments, the vibration device is provided, so that reverberation can be suppressed.

The method for driving a vibration device according to one aspect of the present invention is the method for driving the vibration device, in which sound is generated by vibrating the piezoelectric element.

In one of the above embodiments, the vibration device is driven, so that reverberation can be suppressed.

According to one aspect of the present invention, it is possible to provide a vibration device, an electronic device, and a method for driving the vibration device, which can suppress reverberation.

It is a perspective view of the vibration device which concerns on embodiment. It is an exploded perspective view of the vibration device of FIG. It is sectional drawing along the line III-III of FIG. It is sectional drawing which shows the part of FIG. 3 enlarged. It is an exploded perspective view which shows the structure of a piezoelectric element. It is a top view of the connection structure and the piezoelectric element. It is a top view of the connection structure and the piezoelectric element. It is a bottom view of the connection structure. It is a partially enlarged sectional view of the vibration device which concerns on a modification.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. In the description, the same reference numerals are used for the same elements or elements having the same function, and duplicate description is omitted.

FIG. 1 is a perspective view of the vibration device according to the embodiment. FIG. 2 is an exploded perspective view of the vibration device of FIG. FIG. 3 is a cross-sectional view taken along the line III-III of FIG. FIG. 4 is an enlarged cross-sectional view showing a part of FIG. As shown in FIGS. 1 to 4, the vibration device 100 includes a vibration unit 1, a connection structure 2 connected to the vibration unit 1, and a case 3 in which the vibration unit 1 is arranged. The vibration device 100 is used, for example, as a speaker or a buzzer. The vibration device 100 is provided in an electronic device such as a television or a smartphone.

The case 3 is made of a resin material such as an acrylic resin, a vinyl chloride resin, or a molding resin. The case 3 is, for example, a rectangular parallelepiped box member having an open upper surface. The case 3 has a rectangular plate-shaped bottom portion 3a, a pair of side portions 3b facing each other, and a pair of side portions 3c facing each other.

The bottom portion 3a has a rectangular shape having a pair of long sides and a pair of short sides when viewed from the thickness direction. The rectangular shape includes, for example, a shape in which each corner is chamfered and a shape in which each corner is rounded. The rectangular shape also includes a square shape. In the following, the long side direction of the bottom 3a is the X direction, the short side direction of the bottom 3a is the Y direction, and the thickness direction of the bottom 3a is the Z direction.

The length of the bottom portion 3a in the X direction is, for example, 33 mm. The length of the bottom portion 3a in the Y direction is, for example, 18 mm. The length of the bottom portion 3a in the Z direction is, for example, 1.5 mm. A rectangular recess 3d is formed in the center of the upper surface of the bottom 3a when viewed from the Z direction. The length of the recess 3d in the X direction is, for example, 15 mm. The length of the recess 3d in the Y direction is, for example, 10 mm. The length (depth) of the recess 3d in the Z direction is, for example, 1.0 mm.

The pair of side portions 3b have a rectangular plate shape and extend along the Z direction from the long side portion of the bottom portion 3a. The facing direction of the pair of side portions 3b coincides with the Y direction. A rectangular through hole 3e that penetrates the side portion 3b in the thickness direction (Y direction) is formed in one side portion 3b. In FIG. 3, the through hole 3e is not shown. The sound generated by the vibration device 100 is mainly transmitted to the outside of the case 3 through the through hole 3e. The pair of side portions 3c have a rectangular plate shape and extend along the Z direction from the short side portion of the bottom portion 3a. The facing direction of the pair of side portions 3c coincides with the X direction. The lengths of the side portions 3b and 3c in the Z direction are the same, for example, 7.6 mm.

The case 3 further has a support portion 3f that supports the connection structure 2. The support portion 3f projects from the end portion of one side portion 3c opposite to the bottom portion 3a to the outside of the case 3 along the X direction. The case 3 may have at least a bottom portion 3a, and may not have the side portions 3c, 3b and the support portion 3f.

The vibrating portion 1 is arranged at the bottom portion 3a. In the present embodiment, the vibrating portion 1 is surrounded by a pair of side portions 3b and a pair of side portions 3c on the bottom portion 3a. The vibrating unit 1 is housed in the case 3. The vibrating unit 1 has a piezoelectric element 10 and a vibrating member 12 joined to the piezoelectric element 10.

The vibrating member 12 is made of, for example, a metal such as a Ni—Fe alloy, Ni, brass, or stainless steel. In the present embodiment, the vibrating member 12 is a plate-shaped member. The vibrating member 12 has a pair of main surfaces 12a and 12b facing each other in the Z direction. The vibrating member 12 is arranged so that the outer edge of the vibrating member 12 is located outside the outer edge of the recess 3d when viewed from the Z direction. The vibrating member 12 completely covers the recess 3d.

The main surface 12b faces the bottom 3a in the Z direction. The main surface 12b is bonded (adhered) to the bottom portion 3a by, for example, an adhesive layer 60 made of an epoxy resin or an acrylic resin. The adhesive layer 60 does not contain a conductive filler and has electrical insulation. The main surface 12b is joined to the peripheral edge of the recess 3d in the bottom 3a and is supported by the peripheral edge of the recess 3d.

Each of the main surfaces 12a and 12b has a rectangular shape having a pair of long sides and a pair of short sides. That is, the vibrating member 12 has a rectangular shape having a pair of long sides and a pair of short sides in a plan view (viewed from the Z direction). In the present embodiment, the long side directions of the main surfaces 12a and 12b coincide with the X direction. The short side direction of each of the main surfaces 12a and 12b coincides with the Y direction.

The length of the vibrating member 12 in the X direction is, for example, 30 mm. The length of the vibrating member 12 in the Y direction is, for example, 15 mm. The length of the vibrating member 12 in the Z direction is, for example, 100 μm.

The piezoelectric element 10 has a piezoelectric element 11 and a plurality of external electrodes 13 and 15. In this embodiment, the piezoelectric element 10 has two external electrodes 13 and 15. The external electrode 13 and the external electrode 15 have different polarities from each other.

The piezoelectric element 11 has a rectangular parallelepiped shape. The rectangular parallelepiped shape includes, for example, the shape of a rectangular parallelepiped having chamfered corners and ridges, and the shape of a rectangular parallelepiped having rounded corners and ridges. The piezoelectric element 11 has a pair of main surfaces 11a and 11b facing each other in the Z direction. The main surface 11b faces the main surface 12a in the Z direction. The main surface 11b is joined (adhered) to the central portion of the main surface 12a by the adhesive layer 61.

Each of the main surfaces 11a and 11b has a rectangular shape. Each of the main surfaces 11a and 11b has a rectangular shape having a pair of long sides 11c and a pair of short sides 11d. That is, the piezoelectric element 10 (piezoelectric element 11) has a rectangular shape having a pair of long sides and a pair of short sides in a plan view (viewed from the Z direction). In the present embodiment, the long side directions of the main surfaces 11a and 11b coincide with the X direction. The short side direction of each of the main surfaces 11a and 11b coincides with the Y direction.

The length of the piezoelectric element 11 in the X direction is, for example, 20 mm. The length of the piezoelectric element 11 in the Y direction is, for example, 10 mm. The length of the piezoelectric element 11 in the Z direction is, for example, 200 μm.

FIG. 5 is an exploded perspective view showing the configuration of the piezoelectric element. As shown in FIGS. 4 and 5, the piezoelectric element 11 is configured by laminating a plurality of piezoelectric layers 17a, 17b, 17c, and 17d. That is, the piezoelectric element 11 has a plurality of laminated piezoelectric layers 17a, 17b, 17c, 17d. In the present embodiment, the piezoelectric element 11 has four piezoelectric layers 17a, 17b, 17c, and 17d. In the piezoelectric element 11, the direction in which the plurality of piezoelectric layers 17a, 17b, 17c, and 17d are laminated coincides with the Z direction. The piezoelectric layer 17a has a main surface 11a. The piezoelectric layer 17d has a main surface 11b. The piezoelectric layers 17b and 17c are located between the piezoelectric layer 17a and the piezoelectric layer 17d.

Each of the piezoelectric layers 17a, 17b, 17c, 17d is made of a piezoelectric material. In this embodiment, each of the piezoelectric layers 17a, 17b, 17c, 17d is made of a piezoelectric ceramic material. Piezoelectric ceramic materials include, for example, PZT [Pb (Zr, Ti) O ₃ ], PT (PbTIO ₃ ), PLZT [(Pb, La) (Zr, Ti) O ₃ ], or barium titanate (BaTIO ₃ ). Is used. Each of the piezoelectric layers 17a, 17b, 17c, 17d is composed of, for example, a sintered body of a ceramic green sheet containing the above-mentioned piezoelectric ceramic material. In the actual piezoelectric element 11, the piezoelectric layers 17a, 17b, 17c, and 17d are integrated to such an extent that the boundary between the piezoelectric layers 17a, 17b, 17c, and 17d cannot be recognized.

The piezoelectric element 10 includes a plurality of internal electrodes 19, 21, 23 arranged in the piezoelectric element 11. In this embodiment, the piezoelectric element 10 includes three internal electrodes 19, 21, 23. Each of the internal electrodes 19, 21, 23 is made of a conductive material. As the conductive material, for example, Ag, Pd, or Ag—Pd alloy is used. Each of the internal electrodes 19, 21, 23 is configured as, for example, a sintered body of a conductive paste containing the above conductive material. In the present embodiment, the outer shapes of the internal electrodes 19, 21, 23 are rectangular.

The internal electrodes 19, 21, 23 are arranged at different positions (layers) in the Z direction. The internal electrode 19 and the internal electrode 21 face each other with a gap in the Z direction. The internal electrode 21 and the internal electrode 23 face each other with a gap in the Z direction. The internal electrode 19 is located between the piezoelectric layer 17a and the piezoelectric layer 17b. The internal electrode 21 is located between the piezoelectric layer 17b and the piezoelectric layer 17c. The internal electrode 23 is located between the piezoelectric layer 17c and the piezoelectric layer 17d. The internal electrodes 19, 21, 23 are not exposed on the surface of the piezoelectric element 11. That is, each of the internal electrodes 19, 21, 23 is not exposed on each side surface. The internal electrodes 19, 21, 23 are separated from all the edges (four sides) of the main surfaces 11a and 11b when viewed from the Z direction.

The plurality of external electrodes 13 and 15 are arranged on the main surface 11a. The external electrode 13 and the external electrode 15 are arranged in the X direction. The external electrode 13 and the external electrode 15 are adjacent to each other in the X direction. The plurality of external electrodes 13 and 15 are arranged in the central portion of the main surface 11a. The plurality of external electrodes 13 and 15 are separated from all the edges (four sides) of the main surface 11a when viewed from the Z direction. Each of the external electrodes 13 and 15 has a rectangular shape when viewed from the Z direction. Each of the external electrodes 13 and 15 is made of a conductive material. As the conductive material, for example, Ag, Pd, or Ag—Pd alloy is used. Each of the external electrodes 13 and 15 is configured as, for example, a sintered body of a conductive paste containing the above conductive material.

The external electrode 13 is electrically connected to the connecting conductor 25 through the via conductor 31. The connecting conductor 25 is located on the same layer as the internal electrode 19. The connecting conductor 25 is located inside the internal electrode 19. An opening is formed in the internal electrode 19 at a position corresponding to the external electrode 13 when viewed from the Z direction. The connecting conductor 25 is located in the opening formed in the internal electrode 19. When viewed from the Z direction, the entire edge of the connecting conductor 25 is surrounded by the internal electrode 19.

The connecting conductor 25 is located between the piezoelectric layer 17a and the piezoelectric layer 17b. The internal electrode 19 and the connecting conductor 25 are separated from each other. The connecting conductor 25 faces the external electrode 13 in the Z direction. The via conductor 31 is connected to the external electrode 13 and is also connected to the connecting conductor 25. The connecting conductor 25 is electrically connected to the internal electrode 21 through the via conductor 33. The connecting conductor 25 faces the internal electrode 21 in the Z direction. The via conductor 33 is connected to the connecting conductor 25 and is also connected to the internal electrode 21.

The internal electrode 21 is electrically connected to the connecting conductor 27 through the via conductor 35. The connecting conductor 27 is located on the same layer as the internal electrode 23. The connecting conductor 27 is located inside the internal electrode 23. An opening is formed in the internal electrode 23 at a position corresponding to the external electrode 13 (connecting conductor 25) when viewed from the Z direction. The connecting conductor 27 is located in the opening formed in the internal electrode 23. When viewed from the Z direction, the entire edge of the connecting conductor 27 is surrounded by the internal electrode 23.

The external electrode 15 is electrically connected to the internal electrode 19 through the via conductor 37. The internal electrode 19 faces the external electrode 15 in the Z direction. The via conductor 37 is connected to the external electrode 15 and is connected to the internal electrode 19.

The internal electrode 19 is electrically connected to the connecting conductor 29 through the via conductor 39. The connecting conductor 29 is located on the same layer as the internal electrode 21. The connecting conductor 29 is located inside the internal electrode 21. An opening is formed in the internal electrode 21 at a position corresponding to the external electrode 15 when viewed from the Z direction. The connecting conductor 29 is located in the opening formed in the internal electrode 21. When viewed from the Z direction, the entire edge of the connecting conductor 29 is surrounded by the internal electrode 21.

The connecting conductor 29 is located between the piezoelectric layer 17b and the piezoelectric layer 17c. The internal electrode 21 and the connecting conductor 29 are separated from each other. The connecting conductor 29 faces the internal electrode 19 in the Z direction. The via conductor 39 is connected to the internal electrode 19 and is also connected to the connecting conductor 29. The connecting conductor 29 is electrically connected to the internal electrode 23 through the via conductor 41. The connecting conductor 29 faces the internal electrode 23 in the Z direction. The via conductor 41 is connected to the connecting conductor 29 and is also connected to the internal electrode 23.

The external electrode 13 is electrically connected to the internal electrode 21 through the via conductor 31, the connecting conductor 25, and the via conductor 33. The external electrode 15 is electrically connected to the internal electrode 19 through the via conductor 37. The external electrode 15 is electrically connected to the internal electrode 23 through the via conductor 37, the internal electrode 19, the via conductor 39, the connecting conductor 29, and the via conductor 41.

The connecting conductors 25, 27, 29 and the via conductors 31, 33, 35, 37, 39, 41 are made of a conductive material. Each of the via conductors 31, 33, 35, 37, 39, 41 is a via conductor group composed of a plurality of via conductors, but may be a single via conductor. The via conductors 31 and 33 arranged on the piezoelectric layers 17a and 17b adjacent to each other in the Z direction are arranged so as to be separated from each other and not overlap each other when viewed from the Z direction. The via conductors 37 and 39 arranged on the piezoelectric layers 17a and 17b are arranged so as to be separated from each other and not overlap each other when viewed from the Z direction. The via conductors 33 and 37 arranged on the piezoelectric layers 17b and 17c adjacent to each other in the Z direction are arranged so as to be separated from each other and not overlap each other when viewed from the Z direction. The via conductors 39 and 41 arranged on the piezoelectric layers 17b and 17c are arranged so as to be separated from each other and not overlap each other when viewed from the Z direction.

As the conductive material, for example, Ag, Pd, or Ag—Pd alloy is used. The connecting conductors 25, 27, 29 and the via conductors 31, 33, 35, 37, 39, 41 are configured as, for example, a sintered body of a conductive paste containing the above conductive material. The connecting conductors 25, 27, and 29 have a rectangular shape. The via conductors 31, 33, 35, 37, 39, 41 are sintered by the conductive paste filled in the through holes formed in the ceramic green sheet for forming the corresponding piezoelectric layers 17a, 17b, 17c. It is formed by.

On the main surface 11b of the piezoelectric element 11, the conductor electrically connected to the internal electrodes 19 and 23 and the conductor electrically connected to the internal electrode 21 are not arranged. In the present embodiment, when the main surface 11b is viewed from the Z direction, the entire main surface 11b is exposed. The main surfaces 11a and 11b are natural surfaces. The natural surface is a surface composed of the surfaces of crystal grains grown by firing.

Also on each side surface of the piezoelectric element 11, the conductor electrically connected to the internal electrodes 19 and 23 and the conductor electrically connected to the internal electrode 21 are not arranged. In the present embodiment, when each side surface of the piezoelectric element 11 is viewed from the X direction and the Y direction, the entire side surface is exposed. In this embodiment, each of these aspects is also a natural aspect.

The region sandwiched between the internal electrode 19 and the internal electrode 21 in the piezoelectric layer 17b and the region sandwiched between the internal electrode 21 and the internal electrode 23 in the piezoelectric layer 17c form a piezoelectrically active region. .. In the present embodiment, the piezoelectrically active region is located so as to surround the plurality of external electrodes 13 and 15 when viewed from the Z direction. When viewed from the Z direction, the piezoelectric element 11 includes a piezoelectrically active region in a region located between the external electrode 13 and the external electrode 15. When viewed from the Z direction, the piezoelectric element 11 also includes a piezoelectrically active region outside the region where the external electrode 13 and the external electrode 15 are located.

As shown in FIGS. 1 to 4, the connection structure 2 has a band-shaped wiring member 50 connected to the vibrating portion 1 and a plurality of lead wires 80 connected to the wiring member 50. .. In this embodiment, the connection structure 2 has two lead wires 80.

FIG. 6 is a top view of the connection structure and the piezoelectric element. As shown in FIGS. 1 to 6, the wiring member 50 extends along the long side 11c of the main surface 11a so as to intersect the short side 11d of the main surface 11a. In the present embodiment, the wiring member 50 is arranged so as to be orthogonal to the short side 11d of the main surface 11a. The direction in which the wiring member 50 extends is orthogonal to the Y direction. The wiring member 50 extends in the X direction. The wiring member 50 has one end that is electrically and physically connected to the piezoelectric element 10, and the other end that is electrically and physically connected to the lead wire 80.

The wiring member 50 is located on the plurality of external electrodes 13 and 15. The wiring member 50 is electrically connected to the plurality of external electrodes 13 and 15 by the joining member 70. The joining member 70 is provided between one end of the wiring member 50 and the piezoelectric element 10 so as to integrally cover the plurality of external electrodes 13 and 15 when viewed from the Z direction. The joining member 70 is a resin layer containing a plurality of conductive particles (not shown). The conductive particles are, for example, metal particles and gold-plated particles. The joining member 70 contains, for example, a thermosetting elastomer. The joining member 70 is formed, for example, by curing an anisotropic conductive paste or an anisotropic conductive film.

The wiring member 50 is also joined to the main surface 11a by the joining member 71. The wiring member 50 is joined to the main surface 11a by the joining member 71. The joining member 71 has an insulating property. The joining member 71 is arranged along one short side 11d of the main surface 11a. The joining member 71 joins the entire width direction (Y direction) of the wiring member 50 to the main surface 11a. The joining member 71 is separated from the joining member 70. The joining member 71 contains, for example, nitrile rubber. The joining member 71 may contain the same resin material as the resin material contained in the joining member 70.

The wiring member 50 has a first region R1 that overlaps with the main surface 11a when viewed from an orthogonal direction (Z direction) orthogonal to the main surface 11a. The first region R1 includes the second region R2. The second region R2 is joined to the piezoelectric element 10 by a joining member 70 so as to integrally cover the plurality of external electrodes 13 and 15. The second region R2 covers the entire plurality of external electrodes 13 and 15. The plurality of external electrodes 13 and 15 are not exposed from the second region R2 when viewed from the Z direction.

In the present embodiment, the first region R1 and the second region R2 have a rectangular shape when viewed from the Z direction. The long side direction of the first region R1 and the second region R2 is the X direction, which coincides with the long side direction of the main surface 11a. When viewed from the Z direction, the short side direction of the first region R1 and the second region R2 is the Y direction, which coincides with the short side direction of the main surface 11a.

When viewed from the Z direction, the second region R2 is arranged closer to any one corner portion A1 of the first region R1. That is, when viewed from the Z direction, the second region R2 is biased with respect to the first region R1. In the present embodiment, the corner portion A1 is a corner portion formed by one long side and one short side of the first region R1.

One end of the first region R1 in the Y direction (that is, one long side of the first region R1) and one end of the second region R2 in the Y direction (that is, the length of one of the second regions R2) when viewed from the Z direction. The length L1 between the first region R1 and the other end in the Y direction of the first region R1 (that is, the other long side of the first region R1) and the other end of the second region R2 in the Y direction (that is, the first side). It is different from the length L2 between the two regions R2 (the other long side). The length L1 is shorter than the length L2. The length L1 may be 0. That is, when viewed from the Z direction, one end of the first region R1 in the Y direction and one end of the second region R2 in the Y direction may overlap. The lengths L1 and L2 are, for example, the shortest lengths in the Y direction.

One end of the first region R1 in the X direction (that is, one short side of the first region R1) and one end of the second region R2 in the X direction (that is, one short side of the second region R2) when viewed from the Z direction. The length L3 between the first region R1 and the other end in the X direction of the first region R1 (that is, the other short side of the first region R1) and the other end of the second region R2 in the X direction (that is, the first side). The length L4 between the other short side of the two regions R2) is different. The length L3 is shorter than the length L4. The length L3 may be 0. That is, when viewed from the Z direction, one end of the first region R1 in the X direction and one end of the second region R2 in the X direction may overlap. The lengths L3 and L4 are, for example, the shortest lengths in the X direction.

When viewed from the Z direction, the first region R1 is arranged closer to any one corner A2 of the main surface 11a. That is, when viewed from the Z direction, the first region R1 is biased with respect to the main surface 11a. In the present embodiment, the corner portion A2 is a corner portion formed by the other long side 11c and the other short side 11d of the main surface 11a.

The other end of the main surface 11a in the Y direction (that is, the other long side 11c of the main surface 11a) and the other end of the first region R1 in the Y direction (that is, the other end of the first region R1) when viewed from the Z direction. The length L5 between the long side (long side) is one end of the main surface 11a in the Y direction (that is, one long side 11c of the main surface 11a) and one end of the first region R1 in the Y direction (that is, the first region). It is different from the length L6 between the one long side of R1). The length L5 is shorter than the length L6. The length L5 may be 0. That is, when viewed from the Z direction, the other end of the main surface 11a in the Y direction and the other end of the first region R1 in the Y direction may overlap. The lengths L5 and L6 are, for example, the shortest lengths in the Y direction.

The other end of the main surface 11a in the X direction (that is, the other short side 11d of the main surface 11a) and the other end of the first region R1 in the X direction (that is, the other end of the first region R1) when viewed from the Z direction. The length L7 (not shown) between the short side (not shown) is one end of the main surface 11a in the X direction (that is, one short side 11d of the main surface 11a) and one end of the first region R1 in the X direction (that is, the short side). , One short side of the first region R1) is different from the length L8. The length L7 is shorter than the length L8. The length L7 is 0, but it does not have to be 0. That is, when viewed from the Z direction, the other end of the main surface 11a in the X direction and the other end of the first region R1 in the X direction overlap, but may not overlap. The lengths L7 and L8 are, for example, the shortest lengths in the X direction.

FIG. 7 is a top view of the connection structure and the piezoelectric element. FIG. 8 is a bottom view of the connection structure. As shown in FIGS. 1 to 8, the wiring member 50 has a base 51, a plurality of conductor layers 53, 55, a cover 57, and a reinforcing member 59. In this embodiment, the wiring member 50 includes two conductor layers 53 and 55. The wiring member 50 is, for example, a flexible printed circuit board (FPC) or a flexible flat cable (FFC).

The base 51 has a band shape and has a pair of main surfaces 51a and 51b facing each other. The base 51 has electrical insulation. The base 51 is a resin layer made of a resin such as a polyimide resin. The thickness of the base 51 is, for example, 100 μm.

The conductor layers 53 and 55 are arranged on the main surface 51a of the base 51. The conductor layers 53 and 55 are joined (bonded) to the main surface 51a by an adhesive layer (not shown). Each conductor layer 53, 55 is made of, for example, Cu. Each of the conductor layers 53 and 55 may have, for example, a configuration in which a Ni plating layer and an Au plating layer are provided in this order on the Cu layer. The conductor layer 53 and the conductor layer 55 are arranged apart from each other. The thickness of each conductor layer 53, 55 is, for example, 20 μm.

The conductor layer 53 includes an end portion 53a connected to the lead wire 80, an end portion 53b connected to the external electrode 13, and a connection portion 53c connecting the end portion 53a and the end portion 53b. There is. The connection portion 53c extends in the direction (X direction) in which the wiring member 50 extends. The end portion 53a is adjacent to one end portion of the connection portion 53c in the direction in which the wiring member 50 extends. The end portion 53b is adjacent to the other end portion of the connection portion 53c in the width direction (Y direction) of the wiring member 50.

The conductor layer 55 includes an end portion 55a connected to the lead wire 80, an end portion 55b connected to the external electrode 15, and a connection portion 55c connecting the end portion 55a and the end portion 55b. There is. The connection portion 55c extends in the direction (X direction) in which the wiring member 50 extends. The end portion 55a is adjacent to one end portion of the connection portion 55c in the direction in which the wiring member 50 extends. The end portion 55b is adjacent to the other end portion of the connection portion 55c in the width direction (Y direction) of the wiring member 50.

The end portion 53a and the end portion 55a are arranged apart from each other in the width direction of the wiring member 50. The end portion 53b and the end portion 55b are arranged apart from each other in the extending direction of the wiring member 50. The connecting portion 53c and the connecting portion 55c are arranged parallel to each other and separated from each other in the width direction of the wiring member 50.

A joining member 70 exists between the end portion 53a and the external electrode 13. The end portion 53a and the external electrode 13 are electrically connected to each other through conductive particles contained in the joining member 70. A joining member 70 exists between the end portion 55a and the external electrode 15. The end portion 55a and the external electrode 15 are electrically connected to each other through conductive particles contained in the joining member 70.

The cover 57 is arranged on the main surface 51a, particularly as shown in FIG. The cover 57 covers each of the conductor layers 53 and 55 and the main surface 51a. The cover 57 is bonded (adhered) to each of the conductor layers 53 and 55 and a region of the main surface 51a exposed from each of the conductor layers 53 and 55 by an adhesive layer (not shown). The cover 57 is a resin layer made of a resin such as a polyimide resin. The thickness of the cover 57 is, for example, 25 μm.

The ends 53a and 53b of the conductor layer 53, the ends 55a and 55b of the conductor layer 55, and a part of the main surface 51a are exposed from the cover 57. A part of the main surface 51a is a region arranged between the end portion 53a and the end portion 55a and a region arranged between the end portion 53b and the end portion 55b when viewed from the Z direction. .. The ends 53a, 53b, 55a, 55b are, for example, nickel-plated and gold flash-plated.

The reinforcing member 59 is arranged at the other end of the wiring member 50. The reinforcing member 59 is arranged on the main surface 51b of the base 51. The reinforcing member 59 is joined (adhered) to the main surface 51b by an adhesive layer (not shown). The reinforcing member 59 is a rectangular plate-shaped member having electrical insulation. The reinforcing member 59 is made of, for example, a polyimide resin.

The lead wire 80 has a bundle 81 of a plurality of core wires and a covering member 82 that covers the bundle 81. In this embodiment, the lead wire 80 has 12 core wires. The covering member 82 covers the outer circumference of the bundle 81. The covering member 82 collectively covers the entire plurality of core wires. The ends of the bundle 81 are exposed from the covering member 82 and are connected to the ends 53a, 55a of the conductor layers 53, 55. The ends of the bundle 81 are connected to the ends 53a, 55a by a conductive adhesive. The conductive adhesive is, for example, a heat-meltable metal such as solder. The conductive adhesive may be formed by using a conductive paste containing Au, Cu or the like as the conductive material.

In the driving method of the vibration device 100 and the electronic device provided with the vibration device 100, sound is generated by vibrating the piezoelectric element 10. The vibration of the piezoelectric element 10 may generate not only sound but also tactile sensation.

As described above, in the vibration device 100, the wiring member 50 has a first region R1 that overlaps with the main surface 11a when viewed from the Z direction. The first region R1 includes a second region R2 bonded to the piezoelectric element 10 so as to integrally cover the plurality of external electrodes 13 and 15 of the piezoelectric element 10. The second region R2 is unevenly arranged near the corner A1 of any one of the rectangular first regions R1. In other words, when viewed from the Z direction, the length L1 is shorter than the length L2, and the length L3 is shorter than the length L4.

That is, in the first region R1, the regions other than the second region R2 (hereinafter referred to as peripheral regions) are arranged more on the other end side of the second region R2 than on one end side in the Y direction when viewed from the Z direction. In addition, more are arranged on the other end side of the second region R2 than on one end side in the X direction. As described above, in the vibration device 100, the arrangement of the peripheral region is biased around the second region R2. As a result, the resonance point in the surrounding region shifts. As a result, reverberation can be suppressed.

The first region R1 of the wiring member 50 is joined to the main surface 11a by the joining member 70 and the joining member 71. Therefore, the first region R1 vibrates together with the piezoelectric element 10. Therefore, the first region R1 is unlikely to inhibit the vibration of the piezoelectric element 10. On the other hand, the region other than the first region R1 in the wiring member 50 may hinder the vibration of the piezoelectric element 10. The vibration of the piezoelectric element 10 is the smallest at both ends of the main surface 11a in the X direction, that is, the short side 11d, and is the largest at the center of the main surface 11a in the X direction. Therefore, by arranging the region other than the first region R1 in the wiring member 50 on the short side 11d side where the vibration of the piezoelectric element 10 is the smallest, the influence on the vibration of the piezoelectric element 10 can be suppressed.

In the present embodiment, when viewed from the Z direction, the wiring member 50 extends along the long side 11c of the main surface 11a so as to intersect the short side 11d of the main surface 11a. Therefore, the region other than the first region R1 in the wiring member 50 is arranged on the short side 11d side where the vibration of the piezoelectric element 10 is minimized. Therefore, it is possible to suppress the wiring member 50 from inhibiting the vibration of the piezoelectric element 10 as compared with the case where the wiring member 50 extends along the short side 11d so as to intersect the long side 11c. ..

The second region R2 covers the entire plurality of external electrodes 13 and 15. That is, the plurality of external electrodes 13 and 15 are not exposed from the second region R2 when viewed from the Z direction. Therefore, the occurrence of a short circuit can be suppressed as compared with the case where the plurality of external electrodes 13 and 15 are exposed from the second region R2. Further, since the entire plurality of external electrodes 13 and 15 are covered, peeling of the wiring member 50 can be suppressed.

The second region R2 is arranged in the central portion of the main surface 11a when viewed from the Z direction. As a result, the plurality of external electrodes 13 and 15 are also arranged in the central portion of the main surface 11a. Compared with the case where the plurality of external electrodes 13 and 15 are arranged at the end of the main surface 11a, the piezoelectrically active region can be arranged without bias. Therefore, the piezoelectric element 10 can be vibrated in a well-balanced manner.

The vibration device 100 includes a vibration member 12 joined to the piezoelectric element 10. Therefore, the vibration can be increased.

Since the electronic device according to the present embodiment includes the vibration device 100, reverberation can be suppressed. In the method of driving the vibration device 100, since the vibration device 100 is driven, reverberation can be suppressed.

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

FIG. 9 is a partially enlarged cross-sectional view of the vibration device according to the modified example. As shown in FIG. 9, in the vibration device 100A according to the modified example, the case 3 is not provided with the recess 3d, and the entire surface of the main surface 12b of the vibration member 12 is bonded (adhered) to the bottom 3a by the adhesive layer 60. It differs from the vibration device 100 in that it is used. Even in this case, since the second region R2 is biased with respect to the first region R1, the reverberation can be suppressed.

In the vibration devices 100 and 100A, the first region R1 and the second region R2 have a rectangular shape when viewed from the Z direction, but may have other shapes.

10 ... Piezoelectric element, 11 ... Piezoelectric element, 11a ... Main surface, 11c ... Long side, 11d ... Short side, 12 ... Vibration member, 13,15 ... External electrode, 50 ... Wiring member, 100, 100A ... Vibration device, A1 ... corner, R1 ... first region, R2 ... second region.

Claims (8)

A piezoelectric element having a rectangular main surface and an external electrode arranged on the main surface.
A wiring member located on the external electrode and electrically connected to the external electrode is provided.
The wiring member has a rectangular first region that overlaps the main surface when viewed from an orthogonal direction orthogonal to the main surface.
The first region includes a second region bonded to the piezoelectric element by a bonding member so as to cover the external electrode.
A vibration device in which the second region is arranged closer to the remaining one corner than the three corners of the first region when viewed from the orthogonal direction. A piezoelectric element having a rectangular main surface and an external electrode arranged on the main surface.
A wiring member located on the external electrode and electrically connected to the external electrode.
Equipped with
The wiring member has a first region that overlaps the main surface when viewed from an orthogonal direction orthogonal to the main surface.
The first region includes a second region bonded to the piezoelectric element by a bonding member so as to cover the external electrode.
Seen from the orthogonal direction
The first length between one end of the main surface of the first region in the short side direction and one end of the second region in the short side direction is the other end of the first region in the short side direction. , Unlike the second length between the second region and the other end in the short side direction.
The third length between one end of the main surface of the first region in the long side direction and one end of the second region in the long side direction is the other end of the first region in the long side direction. , A vibrating device different from the fourth length between the second region and the other end in the long side direction. The vibration device according to claim 1 or 2, wherein the wiring member extends along the long side of the main surface so as to intersect the short side of the main surface when viewed from the orthogonal direction. The vibration device according to any one of claims 1 to 3, wherein the second region covers the entire external electrode when viewed from the orthogonal direction. The vibration device according to any one of claims 1 to 4, wherein the second region is arranged in the central portion of the main surface when viewed from the orthogonal direction. The vibration device according to any one of claims 1 to 5, further comprising a vibration member bonded to the piezoelectric element. An electronic device comprising the vibration device according to any one of claims 1 to 6. The method for driving a vibration device according to any one of claims 1 to 6.
A method for driving a vibrating device that generates sound by vibrating the piezoelectric element.

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