vibrating device

Abstract

A vibration device (1) includes a piezoelectric portion (2) including a piezoelectric element (5) and a metal frame (3) holding the piezoelectric portion (2), the frame (3) having a bottom surface portion (11) to which the piezoelectric portion (2) is fixed and a side surface portion (12) erected on an edge portion of the bottom surface portion (11) so as to surround the piezoelectric portion (2), the side surface portion (12) being continuous with the bottom surface portion (11) and inclined with respect to the bottom surface portion (11) in such a manner as to open to the outside of the edge portion.

Description

Technical Field

[0001] This invention relates to vibration devices. Background Technology

[0002] As an existing vibration device, there is, for example, the sound generator described in Japanese Patent Application Publication No. 2015-133750. This existing sound generator includes: a diaphragm, a frame member disposed on the outer periphery of the diaphragm, a piezoelectric element disposed on the diaphragm, and a resin layer filled in the frame of the frame member in a manner that covers the piezoelectric element.

[0003] In such vibrating devices, achieving the desired acoustic characteristics through the vibration of the frame becomes a key feature. Therefore, studying the structure of the frame to improve the acoustic characteristics has become a technical problem. Summary of the Invention

[0004] This invention was made to solve the above-mentioned technical problems, and its purpose is to provide a vibration device that improves acoustic characteristics.

[0005] The vibration device according to one aspect of the present invention comprises: a piezoelectric part including a piezoelectric element; a metal frame holding the piezoelectric part, the frame having a bottom part on which the piezoelectric part is fixed, and a side part erected at the edge of the bottom part in a manner surrounding the piezoelectric part, the side part being continuous with the bottom part and inclined relative to the bottom part in a manner opening outward from the edge.

[0006] In this vibrating device, the frame of the piezoelectric element is made of metal. The side portion surrounding the piezoelectric element is continuous with the bottom portion and is inclined outward relative to the bottom portion. With this structure, vibration is effectively transmitted from the bottom portion where the piezoelectric element is located to the side portion, and the vibration of the side portion and the vibration of the bottom portion can be fully extracted as output. Therefore, the acoustic characteristics are improved.

[0007] Alternatively, both the inner and outer surfaces of the side portion can be inclined relative to the bottom portion. In this case, the overall thickness of the side portion can be suppressed, improving the efficiency of vibration transmission from the bottom portion to the side portion. Therefore, further improvements in acoustic characteristics are achieved.

[0008] Alternatively, the ridge portion and the connection between the bottom and side portions of the piezoelectric element can both be formed into a curved shape, with the radius of curvature of the connection portion being larger than that of the ridge portion of the piezoelectric element. This improves the efficiency of vibration transmission from the bottom portion to the side portion. Furthermore, it allows for ensuring the required area of ​​the side portion for vibration while suppressing the height of the side portion relative to the bottom portion. This contributes to the thinning of the vibration device.

[0009] Alternatively, the piezoelectric part can be rectangular when viewed from above, and the bottom part can be trapezoidal with the sides corresponding to the long side of the piezoelectric part forming the upper and lower bases. The upper base of the bottom part is shorter than the long side of the piezoelectric part, and the lower base is longer than the long side of the piezoelectric part. This structure, in particular, improves the acoustic characteristics in the high-frequency domain.

[0010] Alternatively, the distance between the bottom surface of the base and the long side of the piezoelectric part along the bottom surface can be shorter than the short side of the piezoelectric part. This structure, in particular, improves the acoustic characteristics in the high-frequency domain.

[0011] Alternatively, a first opening can be formed on the bottom side of the bottom surface by not providing a side surface. In this case, vibrations can be effectively extracted from the first opening.

[0012] Alternatively, a second opening may be formed on the upper bottom side of the bottom portion by cutting a portion of the top of the side portion. In this case, the second opening can be used as an outlet for the wiring component.

[0013] Alternatively, the opening area of ​​the first opening can be larger than the opening area of ​​the second opening. In this case, vibrations can be preferentially extracted from the first opening compared to the second opening. Therefore, both improved acoustic characteristics and simplified layout of wiring components are achieved.

[0014] Alternatively, an outward-facing flange can be provided at the top of the side portion. Such a flange can improve the ease of installation when mounting the vibration device to an external device.

[0015] Alternatively, the radius of curvature of the connection between the side portion and the flange portion can be smaller than the radius of curvature of the connection between the bottom portion and the side portion. This suppresses the transmission of vibration from the side portion to the flange portion. Therefore, it prevents the vibration of the side portion from being weakened by the flange portion. Furthermore, it suppresses the reduction in the mounting strength of the vibrating device relative to the external device due to vibration of the flange portion. Attached Figure Description

[0016] Figure 1 This is a perspective view showing one embodiment of the vibration device of the present invention.

[0017] Figure 2 yes Figure 1 The top view of the vibrating device shown.

[0018] Figure 3 yes Figure 1 The front view of the vibrating device shown. Detailed Implementation

[0019] Hereinafter, with reference to the accompanying drawings, preferred embodiments of a vibration device according to one aspect of the present invention will be described in detail.

[0020] Figure 1 This is a perspective view illustrating one embodiment of the vibration device of the present invention. The vibration device 1 is used as an audio device, such as a loudspeaker or buzzer. Figure 1 As shown, the vibration device 1 is configured to include a piezoelectric part 2, a frame 3, and a wiring component 4.

[0021] The piezoelectric part 2 is configured to include a piezoelectric element 5. The piezoelectric element 5 has a piezoelectric body and a pair of external electrodes. The piezoelectric element 5 is formed into a flat cuboid shape in the thickness direction. The cuboid shape may also include a shape with chamfered corners and edges, or a shape with rounded corners and edges. The piezoelectric body is composed of a stack of multiple piezoelectric body layers. Each piezoelectric body layer is formed of a piezoelectric material such as piezoelectric ceramic. Examples of piezoelectric ceramic materials include, for example, PZT[Pb(Zr,Ti)O3], PT(PbTiO3), PLZT[(Pb,La)(Zr,Ti)O3], or barium titanate (BaTiO3).

[0022] Each piezoelectric layer is, for example, a sintered body of a ceramic green sheet containing the aforementioned piezoelectric ceramic. In a practical piezoelectric body, each piezoelectric layer is integrated to the point that the boundaries between the piezoelectric layers are indistinguishable. Multiple internal electrodes (not shown) are disposed within the piezoelectric body. Each internal electrode is formed of a conductive material. Examples of conductive materials include Ag, Pd, and Ag-Pd alloys.

[0023] The piezoelectric part 2 can also be a component in which a vibrating plate is combined with the piezoelectric element 5. The vibrating plate is, for example, a plate-shaped component made of a metal material. Examples of metal materials that make up the vibrating plate include, for example, Ni-Fe alloy, Ni, brass, stainless steel, etc. The vibrating plate is, for example, rectangular. The vibrating plate is disposed on the bottom surface (the surface on the side of the frame 3) of the piezoelectric element 5 and can be fixed to the piezoelectric element 5 and the frame 3 using, for example, adhesive materials, double-sided tape, etc.

[0024] The frame 3 is a component that holds the piezoelectric part 2. The frame 3 is formed, for example, by stamping metal. Examples of metal materials constituting the frame 3 include stainless steel, aluminum, and 42Ni alloy. The frame 3 has a bottom portion 11 and multiple side portions 12. The bottom portion 11 is the portion that fixes the piezoelectric part 2. The side portions 12 are erected such that they surround the piezoelectric part 2 at the edge of the bottom portion 11.

[0025] An outwardly extending flange 13 is provided at the top 12a of the side portion 12. The flange 13 extends from the top 12a of the side portion 12 parallel to the bottom portion 11 with a predetermined width. The flange 13 functions as a mounting part for mounting the vibrating device 1 to an external device. One side of the flange 13 (the side opposite to the bottom portion 11) becomes a mounting surface for mounting components such as double-sided tape. In addition to double-sided tape, adhesives can also be used as mounting components.

[0026] Wiring component 4 is a component that electrically connects the piezoelectric element 2 to an external device. Wiring component 4 is, for example, a flexible printed circuit board (FPC). One end of wiring component 4 is electrically connected to a pair of external electrodes of the piezoelectric element 5. The connection between one end of wiring component 4 and the external electrodes of the piezoelectric element 5 can be made, for example, using an anisotropic conductive adhesive material. The other end of wiring component 4 (not shown) is electrically connected to an external device.

[0027] Next, the structure of the frame 3 and the arrangement relationship between the piezoelectric part 2 and the frame 3 will be explained.

[0028] Figure 2 yes Figure 1 The top view of the vibrating device shown. Figure 3 This is a front view. In Figure 2 and Figure 3 For ease of explanation, the illustration of wiring component 4 is omitted. Figure 3 In the middle, the piezoelectric part 2 is further omitted. For example... Figure 2 and Figure 3 As shown, in this embodiment, the piezoelectric part 2 is rectangular when viewed from above. The planar shape of the piezoelectric part 2 is the planar shape of the piezoelectric element 5 when the piezoelectric part 2 is composed only of the piezoelectric element 5, and the planar shape of the vibrating plate when the piezoelectric part is composed of the piezoelectric element 5 and the vibrating plate.

[0029] The bottom surface 11 of the frame 3 forms a trapezoid when viewed from above. That is, the bottom surface 11 has an upper base 21, a lower base 22, and a pair of hypotenuses 23, 23. Here, as... Figure 2 As shown, the planar shape of the bottom surface 11 is an isosceles trapezoid. The lower base 22 of the bottom surface 11 is larger than the upper base 21. That is, the bottom surface 11 expands from the upper base 21 towards the lower base 22. The piezoelectric part 2 is disposed approximately at the center of the bottom surface 11. The bottom surface 11 is the main vibrating part of the frame 3, directly transmitting the vibration of the piezoelectric part 2.

[0030] The upper base 21 and lower base 22 of the bottom surface 11 extend along the long side 24 of the piezoelectric part 2 when viewed from above. The upper base 21 of the bottom surface 11 is shorter than the long side 24 of the piezoelectric part 2, and the lower base 22 of the bottom surface 11 is longer than the long side 24 of the piezoelectric part 2. A certain distance D1 is provided between the lower base 22 of the bottom surface 11 and the long side 24 of the piezoelectric part 2. The distance D1 is shorter than the short side 25 of the piezoelectric part 2. Similarly, a certain distance D2 is provided between the upper base 21 of the bottom surface 11 and the long side 24 of the piezoelectric part 2. The distance D2 is shorter than the short side 25 of the piezoelectric part 2. In this embodiment, the distance D1 is greater than or equal to the distance D2. The distance D1 may also be less than the distance D2.

[0031] The side portion 12 is provided correspondingly to the upper bottom 21 and a pair of inclined edges 23, 23 of the bottom portion 11. The height of the side portion 12 is greater than the thickness of the piezoelectric portion 2. Thus, the piezoelectric portion 2 disposed on the bottom portion 11 is surrounded by the side portion 12 from three directions other than the lower bottom 22 side. The side portion 12 is smoothly continuous with the bottom portion 11 and is inclined outward relative to the bottom portion 11 in a manner that opens towards the outer edge. The side portion 12 is a subordinate vibrating part of the frame 3, transmitting the vibration of the piezoelectric portion 2 via the bottom portion 11.

[0032] The side portion 12 has a connecting portion 12A to the bottom portion 11, a connecting portion 12B to the flange portion 13, and a middle portion 12C located between the connecting portions 12A and 12B. In this embodiment, as... Figure 3 As shown, the connecting portion 12A and the intermediate portion 12C are formed into an integral arc-shaped cross-section that bulges outward toward the outer side of the frame 3. In this embodiment, the thickness of the connecting portion 12A and the intermediate portion 12C is the same as the thickness of the bottom portion 11, and is constant. Therefore, both the inner surface 12b and the outer surface 12c of the side portion 12 are in a state of slow curvature and inclination relative to the bottom portion 11.

[0033] When the radius of curvature of the ridge portion of the piezoelectric element 5 is set to R1 and the radius of curvature of the connecting portion 12A is set to R2, the radius of curvature R2 of the connecting portion 12A is greater than the radius of curvature R1 of the ridge portion of the piezoelectric element 5. The ratio of the radius of curvature R1 to the radius of curvature R2 is, for example, 1:2 or greater. By making the radius of curvature R2 greater than the radius of curvature R1, the following performance of the bottom portion 11 relative to the piezoelectric element 5 is improved, and the displacement of the bottom portion 11 is sufficiently ensured. As a result, the sound pressure of the vibrating device 1 is increased.

[0034] On the other hand, the connecting portion 12B is formed as a cross-sectional arc shape facing the opposite direction to that of the connecting portion 12A and the intermediate portion 12C. In this embodiment, the thickness of the connecting portion 12B is the same as that of the bottom portion 11, the connecting portion 12A, and the intermediate portion 12C, and is constant. When the radius of curvature of the connecting portion 12B is set to R3, the radius of curvature R3 of the connecting portion 12B is smaller than the radius of curvature R2 of the connecting portion 12A. There are no particular restrictions on the relationship between the radius of curvature R3 of the connecting portion 12B and the radius of curvature R1 of the edge portion of the piezoelectric element 5. The radius of curvature R3 of the connecting portion 12B can be greater than or less than the radius of curvature R1 of the edge portion of the piezoelectric element 5.

[0035] A first opening 31 is formed on the lower bottom 22 side of the bottom portion 11, which is formed by not providing the side portion 12. For example... Figure 3 As shown, the first opening 31 is divided by a bottom portion 11, side portions 12, 12 corresponding to the inclined edges 23, 23 of the bottom portion 11, and an imaginary line connecting one side (the mounting surface facing the external device) of the flange portions 13, 13 on the side portions 12, 12 to each other. When the vibrating device 1 is mounted on the external device, the first opening 31 functions as an outlet for extracting the vibration of the piezoelectric unit 2 to the outside.

[0036] A second opening 32 is formed on the upper bottom 21 side of the bottom portion 11 by cutting a portion of the top 12a of the side portion 12. For example... Figure 3 As shown, the second opening 32 is divided by a cutout 33 formed on the side portion 12 corresponding to the upper bottom 21 of the bottom portion 11, and an imaginary line connecting the tops 12a, 12a of the side portion 12 separated by the cutout 33. The width of the cutout 33 is slightly larger than the width of the wiring component 4. The depth of the cutout 33 from the top 12a of the side portion 12 is the same as or slightly larger than the thickness of the wiring component 4. When the vibrating device 1 is mounted on an external device, the second opening 32 functions as the outlet of the wiring component 4, which is electrically connected to the piezoelectric part 2.

[0037] The bottom surface 33a of the cut portion 33 is higher than the bottom surface 11 than the height of the piezoelectric portion 2 relative to the bottom surface 11 (the height of the top surface of the piezoelectric element 5). The wiring component 4 is inclined between the piezoelectric portion 2 and the cut portion 33, gradually increasing in height towards the cut portion 33, thus applying a certain tension.

[0038] In this embodiment, the opening area S1 of the first opening 31 is larger than the opening area S2 of the second opening 32. Therefore, the vibration of the piezoelectric part 2 can be preferentially extracted from the first opening 31. The frequency characteristics of the vibrating device 1 are determined by the combination of the opening areas S1 and S2. The overall frequency characteristics of the vibrating device 1 are adjusted by utilizing the resonance of the first opening 31 and the resonance of the second opening 32. Furthermore, the corners and edges of the cutout 33 can also be chamfered or rounded. The inner surface of the cutout 33 can also be an inclined surface or a curved surface, so that the width of the cutout 33 increases towards the top 12a of the side surface 12.

[0039] As explained above, in the vibrating device 1, the frame 3 holding the piezoelectric part 2 is made of metal. The side portion 12 surrounding the piezoelectric part 2 is continuous with the bottom portion 11 and is inclined outward relative to the bottom portion 11. With this structure, vibration is effectively transmitted from the bottom portion 11 where the piezoelectric part 2 is disposed to the side portion 12, and the vibration of the side portion 12 and the vibration of the bottom portion 11 can be fully extracted as output. Therefore, the acoustic characteristics are improved.

[0040] In the vibrating device 1, both the inner surface 12b and the outer surface 12c of the side portion 12 are inclined relative to the bottom portion 11. This allows for overall reduction of the thickness of the side portion 12, improving the efficiency of vibration transmission from the bottom portion 11 to the side portion 12. Consequently, further improvements in acoustic characteristics are achieved.

[0041] In the vibrating device 1, the ridge portion of the piezoelectric part 2 and the connection portion 12A between the bottom portion 11 and the side portion 12 are both formed into a curved shape, and the radius of curvature R2 of the connection portion 12A is larger than the radius of curvature R1 of the ridge portion of the piezoelectric element 5. This improves the efficiency of vibration transmission from the bottom portion 11 to the side portion 12. Furthermore, it allows for ensuring the area of ​​the side portion 12 required for vibration while suppressing the height of the side portion 12 relative to the bottom portion 11. This contributes to the thinning of the vibrating device 1.

[0042] In the vibrating device 1, the piezoelectric part 2 is rectangular when viewed from above. Furthermore, the bottom part 11, when viewed from above, is a trapezoid with the sides corresponding to the long side 24 of the piezoelectric part 2 forming an upper base 21 and a lower base 22. Additionally, the upper base of the bottom part 11 is shorter than the long side 24 of the piezoelectric part 2, and the lower base 22 of the bottom part 11 is longer than the long side 24 of the piezoelectric part 2. Moreover, in the vibrating device 1, the distance D between the lower base 22 of the bottom part 11 and the long side 24 of the piezoelectric part 2 along the lower base 22 is shorter than the short side 25 of the piezoelectric part 2. With this structure, the acoustic characteristics in the high-frequency domain are particularly improved.

[0043] In the vibrating device 1, a first opening 31, formed without the side portion 12, is formed on the lower bottom 22 side of the bottom portion 11. This allows vibration to be effectively extracted from the first opening 31. Furthermore, in the vibrating device 1, a second opening 32, formed by cutting a portion of the top 12a of the side portion 12, is formed on the upper bottom 21 side of the bottom portion 11. This allows the second opening 32 to be used as an outlet for the wiring component 4.

[0044] In the vibrating device 1, the opening area S1 of the first opening 31 is larger than the opening area S2 of the second opening 32. Therefore, vibration can be preferentially extracted from the first opening 31 relative to the second opening 32. This achieves both improved acoustic characteristics and simplified layout of the wiring components 4, etc.

[0045] In the vibrating device 1, an outwardly facing flange 13 is provided at the top 12a of the side portion 12. This flange 13 improves the ease of installation when mounting the vibrating device 1 to an external device.

[0046] In the vibrating device 1, the radius of curvature R3 of the connection portion 12B between the side portion 12 and the flange portion 13 is smaller than the radius of curvature R2 of the connection portion 12A between the bottom portion 11 and the side portion 12. This suppresses the transmission of vibration from the side portion 12 to the flange portion 13. Therefore, it prevents the vibration of the side portion 12 from being weakened by the flange portion 13. Furthermore, it suppresses the reduction in the mounting strength of the vibrating device 1 relative to the external device due to vibration of the flange portion 13.

[0047] The present invention is not limited to the above embodiments. For example, in the above embodiments, the planar shape of the bottom part 11 of the frame 3 is trapezoidal, but the planar shape of the bottom part 11 is not limited to this, and can also be other shapes such as rectangle, square, circle, ellipse, etc.

[0048] Furthermore, in the above embodiment, the connecting portion 12A and the intermediate portion 12C are integrally formed with a circular arc cross-section. However, it is also possible to only make the connecting portion 12A with a circular arc cross-section and make the intermediate portion 12C a flat inclined surface. In this case, the inclination angle of the intermediate portion 12C relative to the bottom surface 11 can be set to, for example, 30° to 90°. In such a structure, by making the side portion 12 continuous with the bottom surface 11 and inclined outward relative to the bottom surface 11, the same effect as the structure described above is achieved.

Claims

1. A vibrating device, wherein, have: The piezoelectric part includes a piezoelectric element; and A metal frame that holds the piezoelectric part. The frame has a bottom portion on which the piezoelectric part is fixed, and a side portion that is erected on the edge of the bottom portion in a manner that surrounds the piezoelectric part. The side portion is continuous with the bottom portion and slopes outward relative to the bottom portion in a manner that opens outward from the edge portion. The ridge portion of the piezoelectric element and the connection portion between the bottom portion and the side portion are both formed into a curved shape. The radius of curvature of the connecting portion is greater than the radius of curvature of the ridge portion of the piezoelectric element.

2. The vibration device according to claim 1, wherein, Both the inner and outer surfaces of the side portion are inclined relative to the bottom portion.

3. The vibration device according to claim 1 or 2, wherein, An outwardly protruding flange is provided at the top of the side portion.

4. The vibration device according to claim 3, wherein, The radius of curvature of the connection portion between the side portion and the flange portion is smaller than the radius of curvature of the connection portion between the bottom portion and the side portion.

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