Vibration device

Abstract

Provided is a vibration device that makes it possible for foreign matter adhered to a translucent body to be removed. A vibration device according to the present invention comprises a substantially cylindrical internal vibration body that can amplify vibration and extends in a first direction, a piezoelectric element that is connected to one end in the first direction of the internal vibration body and can generate vibration, a translucent body that is connected to the other end in the first direction of the internal vibration body and has an optical axis that extends along the first direction, and a substantially cylindrical external vibration body that is provided to surround the internal vibration body and extends in the first direction. The external vibration body has a first connection part that is connected to the translucent body, an attenuator part that extends from the first connection part to the outside of the translucent body along a second direction that intersects the first direction and is configured to dampen vibration, and a cylinder part that is connected to the first connection part and the attenuator part and extends along the first direction. The cylinder part is provided at a gap from the internal vibration body in the second direction, and at least one of the attenuator part and the cylinder part is non-axisymmetric with respect to the optical axis.

Description

vibration device

[0001] The present invention relates to a vibration device.

[0002] Patent document 1 discloses a vibration device equipped with an imbalance means for removing or adding mass to at least one of a translucent body, a first cylindrical body, a second cylindrical body, a spring portion, and a vibrating body.

[0003] Patent No. 6819846

[0004] The vibration device of Patent Document 1 has room for improvement in terms of removing foreign matter adhering to the light-transmitting body.

[0005] An object of the present invention is to provide a vibration device capable of removing foreign matter adhering to a light-transmitting body.

[0006] A vibration device according to one embodiment of the present invention comprises: a substantially cylindrical internal vibrator capable of amplifying vibrations and extending in a first direction; a piezoelectric element connected to one end of the internal vibrator in the first direction and capable of generating vibrations; a translucent body connected to the other end of the internal vibrator in the first direction and having an optical axis extending along the first direction; and a substantially cylindrical external vibrator arranged to surround the internal vibrator and extending in the first direction, wherein the external vibrator has a first connection portion connected to the translucent body, an attenuator portion extending from the first connection portion outward from the translucent body along a second direction intersecting the first direction and configured to attenuate vibrations, and a cylinder portion connecting the first connection portion and the attenuator portion and extending along the first direction, wherein the cylinder portion is arranged at a distance from the internal vibrator in the second direction, and at least one of the attenuator portion and the cylinder portion is non-axially symmetrical with respect to the optical axis.

[0007] According to the present invention, it is possible to provide a vibration device capable of removing foreign matter adhering to a light-transmitting body.

[0008] Schematic perspective view showing a vibration device according to an embodiment of the present invention. Schematic cross-sectional view taken along line II-II of FIG. 1. Schematic perspective view of the vibration device of FIG. 1 as seen from below. Schematic perspective view showing an external vibrator in the vibration device of FIG. 1. Schematic cross-sectional view taken along line V-V of FIG. 4. Schematic cross-sectional view of the external vibrator excluding the fixing part in the vibration device of FIG. 1. Schematic bottom view of the external vibrator excluding the fixing part shown in FIG. 6A. Schematic cross-sectional view taken along line VIC-VIC of FIG. 6A. Schematic cross-sectional perspective view showing an arrangement example of the vibration device. Graph illustrating the displacement amount of the lens surface of the vibration device of FIG. 1. Schematic cross-sectional view illustrating the natural vibration of the internal vibrator of the vibration device of FIG. 1. Schematic cross-sectional view illustrating the natural vibration (mode A) of the external vibrator of the vibration device of FIG. 1. Schematic cross-sectional view illustrating the natural vibration (mode B) of the external vibrator of the vibration device of FIG. 1. Schematic cross-sectional view showing another example of the external vibrator excluding the fixing part. Schematic bottom view of the external vibrator excluding the fixing part shown in FIG. 10A. Schematic cross-sectional view showing a vibration device of Modification 1. Schematic cross-sectional view showing the external vibrator excluding the fixing part in the vibration device of FIG. 11. Cross-sectional view taken along line XIIB-XIIB of FIG. 12A. Schematic perspective view showing an arrangement example of the vibration device of FIG. 11. Graph illustrating the displacement amount of the lens surface of the vibration device of FIG. 11. Schematic cross-sectional view showing a vibration device of Modification 2. Graph illustrating the displacement amount of the lens surface of the vibration device of FIG. 15. Schematic perspective view showing a vibration device of Modification 3. Schematic cross-sectional view taken along line XVIII-XVIII of FIG. 17.

[0009] Various aspects of the present invention will be described.

[0010] a piezoelectric element connected to one end of the internal vibrator in the first direction and capable of generating vibrations; a light-transmitting body connected to the other end of the internal vibrator in the first direction and having an optical axis extending along the first direction; and a light-transmitting body arranged to surround the internal vibrator and extending in the first direction, the light-transmitting body having a substantially cylindrical shape; the external vibrator having a first connection portion connected to the light-transmitting body; an attenuator portion extending from the first connection portion to the outside of the light-transmitting body along a second direction intersecting the first direction and configured to attenuate vibrations; and a cylinder portion connecting the first connection portion and the attenuator portion and extending along the first direction, the cylinder portion being arranged at a distance from the internal vibrator in the second direction, and at least one of the attenuator portion and the cylinder portion being non-axially symmetrical with respect to the optical axis.

[0011] A second aspect of the vibration device of the present invention is the vibration device of the first aspect, wherein, in a cross-sectional view along the optical axis, the attenuator section has a first attenuator section and a second attenuator section positioned symmetrically with respect to the optical axis, and the thickness of the first attenuator section in the first direction is different from the thickness of the second attenuator section in the first direction.

[0012] A third aspect of the vibration device of the present invention is a vibration device of the first or second aspect, wherein, in a cross-sectional view along the optical axis, the cylinder portion has a first cylinder portion and a second cylinder portion positioned symmetrically with respect to the optical axis, and the thickness of the first cylinder portion in the second direction is different from the thickness of the second cylinder portion in the second direction.

[0013] A fourth aspect of the vibration device of the present invention is the vibration device of the third aspect, wherein the cylinder portion has a first member and a second member, the first cylinder portion is composed of a part of the first member, the second cylinder portion is composed of another part of the first member and the second member, and in the second cylinder portion, the second member is located inside the first member.

[0014] A fifth aspect of the present invention is the vibration device of any one of the first to fourth aspects, wherein both the attenuator section and the cylinder section are asymmetrical with respect to the optical axis.

[0015] A sixth aspect of the vibration device of the present invention is the vibration device of the fifth aspect, wherein, in a cross-sectional view along the optical axis, the attenuator section has a first attenuator section and a second attenuator section positioned symmetrically with respect to the optical axis, the cylinder section has a first cylinder section and a second cylinder section positioned symmetrically with respect to the optical axis, the first attenuator section and the first cylinder section are positioned on one side of the optical axis, and the second attenuator section and the second cylinder section are positioned on the other side of the optical axis, the thickness in the first direction of the first attenuator section is greater than the thickness in the first direction of the second attenuator section, and the thickness in the second direction of the first cylinder section is smaller than the thickness in the second direction of the second cylinder section.

[0016] A seventh aspect of the vibration device of the present invention is a vibration device according to any one of the first to sixth aspects, wherein, in a cross-sectional view along the optical axis, the attenuator section has a first attenuator section and a second attenuator section positioned symmetrically with respect to the optical axis, and the material constituting the first attenuator section is different from the material constituting the second attenuator section.

[0017] An eighth aspect of the vibration device of the present invention is the vibration device of any one of the first to seventh aspects, wherein, in a cross-sectional view along the optical axis, the cylinder portion has a first cylinder portion and a second cylinder portion positioned symmetrically with respect to the optical axis, and the first cylinder portion is made of a different material than the second cylinder portion.

[0018] A vibration device of a ninth aspect of the present invention is the vibration device of any one of the first to eighth aspects, wherein, in a cross-sectional view along the optical axis, the external vibrator has a first external vibrator and a second external vibrator positioned symmetrically with respect to the optical axis, and when the amplitude of the first external vibrator due to vibrations generated by the piezoelectric element is larger than the amplitude of the second external vibrator due to vibrations generated by the piezoelectric element, the second external vibrator is positioned vertically above the first external vibrator.

[0019] A vibration device according to a tenth aspect of the present invention is the vibration device according to any one of the first to ninth aspects, wherein the internal vibrator has axial symmetry with respect to the optical axis.

[0020] An eleventh aspect of the present invention is the vibration device of any one of the first to tenth aspects, wherein the piezoelectric element has axial symmetry with respect to the optical axis.

[0021] A vibration device of a twelfth aspect of the present invention is the vibration device of any one of the first to eleventh aspects, wherein, in a cross-sectional view along the optical axis, the external vibration body has a first external vibration body and a second external vibration body positioned symmetrically with respect to the optical axis, and when the amplitude of the first external vibration body due to vibration generated in the piezoelectric element is greater than the amplitude of the second external vibration body due to vibration generated in the piezoelectric element, wiring is connected to the piezoelectric element from a position closer to the second external vibration body than the first external vibration body.

[0022] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the present disclosure is not limited to these embodiments. In addition, substantially identical components in the drawings are designated by the same reference numerals. For illustrative purposes, the dimensions of each element in the drawings may be exaggerated and are not necessarily drawn to scale.

[0023] Furthermore, for the sake of convenience in the following explanation, terms indicating directions such as "up," "down," "right," "left," and "side" are used assuming a state of normal use, but this is not intended to limit the state of use of the vibration device according to the present disclosure.

[0024] In the drawings described below, for reference, the X-axis and Z-axis, which are perpendicular to each other, are shown schematically. In the following description, when the X-direction or Z-direction is simply mentioned, it refers to the respective axial direction and includes two opposite directions (for example, the -X-direction and the +X-direction).

[0025] Fig. 1 is a perspective view showing a vibration device according to one embodiment of the present invention. Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1. Fig. 3 is a perspective view of the vibration device of Fig. 1 as seen from below. In these figures, the direction along the optical axis L of the light-transmitting body of the vibration device is defined as the Z direction (or first direction), and the radial direction of an imaginary circle centered on the optical axis L on a plane perpendicular to the Z direction is defined as the X direction (or second direction).

[0026] As shown in FIGS. 1 to 3, the vibration device 1 includes an internal vibrator 7, a piezoelectric element 9, a lens (an example of a light-transmitting body) 5, and an external vibrator 3.

[0027] <Internal vibrator 7> As shown in Fig. 2, the internal vibrator 7 is a substantially cylindrical body extending in the first direction Z. The piezoelectric element 9 is connected to one end of the internal vibrator 7 in the first direction Z (the lower end in Fig. 2). The lens 5 is connected to the other end of the internal vibrator 7 in the first direction Z (the upper end in Fig. 2). The lens 5 has an optical axis L extending along the first direction Z. Vibrations generated by the piezoelectric element 9 are transmitted to the lens 5 via the internal vibrator 7, causing the lens 5 to vibrate. This removes foreign matter such as water droplets or mud adhering to the lens 5.

[0028] The internal vibrator 7 is configured to be able to amplify the vibrations generated by the piezoelectric element 9. The internal vibrator 7 is made of, for example, a metal material or ceramics. Examples of metal materials that make up the internal vibrator 7 include stainless steel, aluminum, iron, titanium, and duralumin. The surface of the internal vibrator 7 may be subjected to a surface treatment such as oxidation or alumite treatment in order to improve the adhesion of the adhesive. For example, by making the surface of the internal vibrator 7 black through surface treatment, it is possible to prevent a decrease in optical performance due to diffuse reflection of light.

[0029] In the present embodiment, the internal vibrator 7 has, as an example, a substantially cylindrical shape extending along the first direction Z, and is positioned symmetrically with respect to the optical axis L. The internal vibrator 7 includes an upper portion 71 in contact with the lens 5, a lower portion 72 to which the piezoelectric element 9 is attached, and an intermediate portion 73 connecting the upper portion 71 and the lower portion 72.

[0030] The upper portion 71 has a cylindrical plate-like portion 711 and a protruding portion 712 that protrudes from the plate-like portion 711 toward the optical axis L in a second direction X intersecting the first direction Z. The protruding portion 712 is, for example, annular in plan view from the first direction Z. The peripheral portion (lower edge) of the lens 5 is supported by the inner surface of the plate-like portion 711 and the upper surface of the protruding portion 712. More specifically, at the lower edge of the lens 5, the lower surface of the lens 5 contacts the upper surface of the protruding portion 712, and the side surface of the lens 5 contacts the inner surface (inner periphery) of the plate-like portion 711. The lower portion 72 is configured to vibrate together with the vibration of the piezoelectric element 9 and has a greater plate thickness than the upper portion 71 and the middle portion 73. This facilitates more efficient transmission of the vibration of the piezoelectric element 9 to the lens 5. The middle portion 73 has a substantially S-shaped cross section. The middle portion 73 is configured to support the upper portion 71 and to transmit vibrations of the lower portion 72 to the upper portion 71 .

[0031] The upper portion 71, the lower portion 72, and the intermediate portion 73 may be formed integrally or separately. The maximum dimension of the intermediate portion 73 in the second direction X (hereinafter referred to as the "maximum outer dimension") is larger than the maximum outer dimension of the upper portion 71, and the maximum outer dimension of the lower portion 72 is larger than the maximum outer dimension of the intermediate portion 73. This allows the vibration of the piezoelectric element 9 to be efficiently transmitted to the lens 5.

[0032] <External vibrator 3> The external vibrator 3 is configured to prevent the vibrations of the internal vibrator 7 from escaping to members other than the lens 5 and to efficiently transmit the vibrations to the lens 5. As an example, the external vibrator 3 is configured to cover the entire internal vibrator 7 and protect the internal vibrator 7 from the outside. The external vibrator 3 is made of, for example, a metal material such as stainless steel, aluminum, iron, titanium, or duralumin, or a resin.

[0033] Fig. 4 is a schematic perspective view showing an external vibrator in the vibration device of Fig. 1. Fig. 5 is a cross-sectional view taken along line VV in Fig. 4.

[0034] 1 to 5, the external vibrator 3 is a generally cylindrical body extending in the first direction Z. The external vibrator 3 extends in the first direction Z and has a through-hole with a circular cross-section. The external vibrator 3 is disposed so as to surround the internal vibrator 7. In other words, the internal vibrator 7 is located inside the through-hole of the external vibrator 3.

[0035] 2 and 4, the external vibrator 3 includes a substantially cylindrical upper cylindrical body 41 and a substantially prismatic (here, substantially rectangular) lower cylindrical body 42. The upper cylindrical body 41 is located above (closer to the lens 5) the lower cylindrical body 42. The maximum outer dimension of the upper cylindrical body 41 is smaller than the maximum outer dimension of the lower cylindrical body 42.

[0036] In this embodiment, the external vibrator 3 includes a first connecting portion 31, a cylinder portion 32, an attenuator portion 33, a second connecting portion 34, and a fixing portion 35. The first connecting portion 31, the cylinder portion 32, the attenuator portion 33, the second connecting portion 34, and an upper portion 351 of the fixing portion 35 are all cylindrical, and form an upper cylindrical body 41. A lower portion 352 of the fixing portion 35 forms a lower cylindrical body 42.

[0037] The first connection portion 31 is connected to the lens 5. In this embodiment, the first connection portion 31 is located on the upper end side of the external vibrator 3 and has a cylindrical shape extending in the first direction Z. As shown in FIG. 2 , the inner surface (inner circumferential surface) of the first connection portion 31 is in contact with the outer surface (outer circumferential surface) of the internal vibrator 7. The first connection portion 31 is connected to the lens 5 via the internal vibrator 7. Note that the first connection portion 31 only needs to be fixed to the lens 5, and may be connected to the lens 5 via the internal vibrator 7 or without via the internal vibrator 7 (for example, only via an adhesive).

[0038] 2 , the outer surface of the first connection portion 31 is covered with a cover member 8. The cover member 8 is arranged so as to cover the outer surface and upper surface of the first connection portion 31, the upper end portion of the internal vibrator 7 (here, the upper surface of the plate-shaped portion 711), and the peripheral portion of the upper surface 53 of the lens 5. The cover member 8 is, for example, a resin member or a metal member. By arranging the cover member 8 so as to connect the first connection portion 31 and the lens 5, the first connection portion 31 and the lens 5 are more reliably connected and moisture and foreign matter on the lens 5 are less likely to enter the interior of the external vibrator 3.

[0039] The cylinder portion 32 is located below the first connection portion 31 (on the piezoelectric element 9 side). The cylinder portion 32 is located between the first connection portion 31 and the attenuator portion 33 in the first direction Z and connects the first connection portion 31 and the attenuator portion 33. The cylinder portion 32 has a cylindrical shape extending along the first direction Z. As shown in FIG. 2 , in a cross-sectional view along the optical axis L, the cylinder portion 32 is spaced apart from the internal vibrator 7 in the second direction (radial direction) X and is disposed so as to surround the outer periphery of the internal vibrator 7. The inner diameter of the cylinder portion 32 is larger than the inner diameter of the first connection portion 31. This forms a step on the inner surface of the external vibrator 3 and a gap between the cylinder portion 32 and the outer surface of the internal vibrator 7. The cylinder portion 32 has a smaller thickness (wall thickness) than the fixing portion 35 and thus has spring characteristics. The cylinder portion 32 may include an inclined portion whose diameter gradually increases as it approaches the attenuator portion 33.

[0040] The attenuator section 33 extends from the lower end of the cylinder section 32 outward from the lens 5 in the second direction X. The attenuator section 33 is configured to attenuate vibrations generated by the piezoelectric element 9. The attenuator section 33 has a thickness (wall thickness) smaller than that of the fixed section 35 and therefore has spring characteristics. The attenuator section 33 is spaced apart from the internal vibrator 7 in the second direction X and is disposed so as to surround the outer periphery of the internal vibrator 7. The upper surface of the attenuator section 33 is, for example, annular and positioned symmetrically with respect to the optical axis L.

[0041] In this embodiment, the attenuator portion 33 and the cylinder portion 32 of the external vibrator 3 are each non-axially symmetrical with respect to the optical axis L. With this configuration, it is possible to tilt the amplitude of vibration of the lens 5 connected to the first connection portion 31 of the external vibrator 3. A specific non-axially symmetrical structure will be described later. In this specification, "tilting the amplitude of the lens 5" means forming, on the upper surface 53 of the lens 5, a region where the lens 5 vibrates with a large amplitude and a region where the lens 5 vibrates with a small amplitude.

[0042] The second connection portion 34 connects the attenuator portion 33 and the fixed portion 35. The second connection portion 34 has a cylindrical shape that extends downward (here, in the −Z direction) from the periphery of the attenuator portion 33. The second connection portion 34 is, for example, formed integrally with the attenuator portion 33. The second connection portion 34 allows the attenuator portion 33 and the fixed portion 35 to be disposed at a distance from each other in the first direction Z.

[0043] The fixed portion 35 is located closer to the piezoelectric element 9 than the attenuator portion 33, and is connected to the attenuator portion 33 by the second connection portion 34. The fixed portion 35 is configured to be able to suppress vibrations propagated to members (e.g., a case that houses the imaging element and a lens module) connected to the fixed portion 35. The thickness of the fixed portion 35 (thickness in the second direction X) is greater than other portions of the external vibrator 3.

[0044] As described above, the fixing portion 35 has a cylindrical upper portion 351 and a rectangular prism-shaped lower portion 352. In the example shown in Figures 2 and 4, the second connecting portion 34 is connected to the outer peripheral surface of the upper portion 351 of the fixing portion 35. More specifically, the inner surface of the lower end portion of the second connecting portion 34 contacts the outer surface of the upper portion 351 of the fixing portion 35 (for example, via an adhesive), and the lower surface of the second connecting portion 34 contacts the upper surface of the lower portion 352 of the fixing portion 35.

[0045] The larger the volume of the fixed portion 35, the more the vibration of the fixed portion 35 can be suppressed; however, simply increasing the size of the fixed portion 35 is difficult when miniaturizing the vibration device 1. In this embodiment, the lower portion 352 of the fixed portion 35 has an outer shape of a substantially square prism. This configuration allows the volume of the fixed portion 35 to be increased without increasing the size of the vibration device 1. For example, the volume of a 25 mm x 25 mm cube is larger than that of a cylinder with a diameter of 25 mm. The external vibrator 3 is made of a material with a lower Young's modulus than the internal vibrator 7. This configuration allows for greater vibration attenuation by the attenuator unit 33.

[0046] In the external vibrator 3, the maximum width (maximum outer dimension) of the first connecting portion 31 in the second direction (radial direction) X is smaller than the maximum outer dimension of the cylinder portion 32. The maximum outer dimension of the cylinder portion 32 is smaller than the maximum outer dimension of the attenuator portion 33. The maximum outer dimensions of the attenuator portion 33 and the second connecting portion 34 are substantially the same and are smaller than the maximum outer dimension of the fixed portion 35. With this configuration, the portion of the external vibrator 3 located on the lens 5 side is made more susceptible to vibration, and vibration of the lower portion 352 of the fixed portion 35 is suppressed.

[0047] In this embodiment, only the first connection portion 31 at the upper end of the external vibrator 3 is connected to the internal vibrator 7 or the lens 5. Portions of the external vibrator 3 located below the first connection portion 31 (here, the cylinder portion 32, the attenuator portion 33, the second connection portion 34, and the fixing portion 35) are not in contact with the internal vibrator 7. With this configuration, it is possible to more efficiently impart a tilt to the amplitude of the lens 5 without significantly impairing the axial symmetry of the vibration of the internal vibrator 7 (vibration along the first direction Z).

[0048] The first connecting portion 31, the cylinder portion 32, the attenuator portion 33, the second connecting portion 34, and the fixed portion 35 may be formed integrally or separately. As shown in the figure, the first connecting portion 31, the cylinder portion 32, the attenuator portion 33, and the second connecting portion 34 may be formed integrally, separately from the fixed portion 35. By forming at least the cylinder portion 32 and the attenuator portion 33 integrally, it is possible to more efficiently impart non-axial symmetry to the vibration of the lens 5.

[0049] <Lens 5> The lens 5 is made of, for example, glass. As shown in FIG. 2, the upper surface 53 of the lens 5 has a convex shape, and as an example, the surface is coated with a water-repellent coating and an anti-reflection film (AR coating). The surface (lower surface) of the lens 5 on the optical image forming plane side is made up of a flat portion 51 and a recessed portion 52. The peripheral portion of the upper surface 53 of the lens 5 is connected to the cover member 8 by, for example, an adhesive. The flat portion 51 is connected to the upper portion 71 of the internal vibrator 7 by, for example, an adhesive.

[0050] <Piezoelectric Element 9> The piezoelectric element 9 has a piezoelectric body and electrodes, and is configured to be able to generate vibrations. The piezoelectric body is, for example, barium titanate (BaTiO ３ ), lead zirconate titanate (PZT: PbTiO ３ PbZrO ３ ), lead titanate (PbTiO ３ ), lead metaniobate (PbNb ２ O ６ ), bismuth titanate (Bi ４ Ti ３ O １２ ), (K,Na)NbO ３ Suitable piezoelectric ceramics such as LiTaO ３ , LiNbO ３ The electrodes are made of, for example, Ni, Ag, or Au.

[0051] 2, the piezoelectric element 9 is positioned symmetrically with respect to the optical axis L. In a plan view seen along the first direction Z, the piezoelectric element 9 has, for example, an annular shape. The piezoelectric element 9 is connected to the lower portion 72 of the internal vibrator 7 by, for example, an adhesive.

[0052] An adhesive is placed between the lens 5 and the internal vibrator 7, between the piezoelectric element 9 and the internal vibrator 7, and between the cover member 8 and the lens 5, the internal vibrator 7, and the external vibrator 3. The adhesive is made of, for example, epoxy resin. Using an adhesive with a high Young's modulus can reduce the transmission loss of vibration between two members.

[0053] <Non-axisymmetric structure of external vibrator> The non-axisymmetric structure of the external vibrator will be described in detail below with reference to Fig. 2 and Fig. 4 to Fig. 6C. Fig. 6A is a schematic perspective view showing the external vibrator with the fixing portion removed. Fig. 6B is a bottom view of the external vibrator shown in Fig. 6A, viewed from below. Fig. 6C is a schematic cross-sectional view taken along line VIC-VIC in Fig. 6A.

[0054] 6A , in a cross-sectional view along the optical axis L, the attenuator section 33 includes a first attenuator section 331 and a second attenuator section 332 that are positioned symmetrically with respect to the optical axis L. A thickness t1 of the first attenuator section 331 in the first direction Z and a thickness t2 of the second attenuator section 332 in the first direction Z are different.

[0055] In this embodiment, the thickness t1 of the first attenuator section 331 is greater than the thickness t2 of the second attenuator section 332. As an example, the surface (upper surface) of the first attenuator section 331 facing the lens 5 in the first direction Z and the upper surface of the second attenuator section 332 are located on approximately the same plane (here, on a plane perpendicular to the first direction Z). On the other hand, the surface (lower surface) of the first attenuator section 331 facing the piezoelectric element 9 in the first direction Z is located closer to the piezoelectric element 9 (towards the −Z side) than the lower surface of the second attenuator section 332.

[0056] The attenuator section 33 is composed of a thick section 33a and a thin section 33b having a thickness t2. The thick section 33a is thicker than the thin section 33b. Here, the thick section 33a includes a section having a thickness t1 and a connection section located outside the section having a thickness t1 and connected to the second connection section 34. The width of the thick section 33a in the second direction X in the first attenuator section 331 (w1 in the first section Q1) is larger than the width of the thick section 33a in the second attenuator section 332 (w2 in the second section Q2). The width w2 of the thick section 33a in the second section Q2 is, for example, approximately the same as the thickness of the second connection section 34 in the second direction X. In the example shown in FIG. 6B , the thick section 33a extends in the circumferential direction. The width of the thick portion 33a in the second direction X is configured to be maximum at the first portion Q1 of the first attenuator portion 331 and to be minimum at the second portion Q2 opposite to the first portion Q1 of the second attenuator portion 332, gradually decreasing along the circumferential direction from the first portion Q1 to the second portion Q2.

[0057] 6A , in a cross-sectional view along the optical axis L, the cylinder portion 32 includes a first cylinder portion 321 and a second cylinder portion 322 that are positioned symmetrically with respect to the optical axis L. The first cylinder portion 321 is positioned on the same side of the optical axis L as the first attenuator portion 331, and the second cylinder portion 322 is positioned on the same side of the optical axis L as the second attenuator portion 332. In a cross-sectional view along the optical axis L, a thickness s1 of the first cylinder portion 321 in the second direction X and a thickness s2 of the second cylinder portion 322 in the second direction X are different.

[0058] In this embodiment, the thickness s1 of the first cylinder portion 321 is smaller than the thickness s2 of the second cylinder portion 322. In the example shown in Fig. 6C, the thickness of the cylinder portion 32 in the second direction X is smallest at a first portion R1 of the first cylinder portion 321 and is largest at a second portion R2 of the second cylinder portion 322 that faces the first portion R1, and is configured to gradually increase in thickness along the circumferential direction from the first portion R1 to the second portion R2.

[0059] As an example, the first portion R1 of the cylinder portion 32 is adjacent to the first portion Q1 of the attenuator portion 33 (located in the same direction as viewed from the optical axis L), and the second portion R2 of the cylinder portion 32 is adjacent to the second portion Q2 of the attenuator portion 33. With this configuration, the non-axial symmetry of the cylinder portion 32 and the attenuator portion 33 can be combined to more easily adjust the amplitude.

[0060] 2 and 5, in a cross-sectional view along the optical axis L, the external vibrator 3 includes a first external vibrator 3L located on one side of the optical axis L (-X side, left side in FIG. 2) and a second external vibrator 3R located on the other side of the optical axis L (+X side, right side in FIG. 2). The first external vibrator 3L includes a first attenuator portion 331 and a first cylinder portion 321. The second external vibrator 3R includes a second attenuator portion 332 and a second cylinder portion 322.

[0061] In this embodiment, the external vibrator 3 is configured such that the amplitude of vibration generated by the piezoelectric element 9 is larger in the first external vibrator 3L than in the second external vibrator 3R due to the non-axisymmetric nature of the attenuator section 33 and the cylinder section 32. As an example, the amplitude of vibration of the external vibrator 3 has a gradient that gradually decreases from the first portions Q1, R1 to the second portions Q2, R2 in a plan view seen along the first direction Z. This makes it possible to gradient the amplitude of the lens 5 connected to the first connection section 31. In particular, the amplitude of vibration in a region of the surface of the lens 5 located on the first external vibrator 3L side can be made larger than the amplitude of vibration in a region located on the second external vibrator 3R side.

[0062] 7 is a cross-sectional perspective view showing an example of the arrangement of the vibration device 1. The vibration device 1 is arranged, for example, so that the second external vibrator 3R, which has a relatively small amplitude, is positioned vertically above the first external vibrator 3L, which has a relatively large amplitude. By arranging them in this manner, the amplitude of a first point P1, which is positioned vertically below, on the surface of the lens 5 can be made larger than the amplitude of a second point P2, which is positioned vertically above.

[0063] The first point P1 is, for example, a point located near the portion of the exposed surface of the lens 5 where the attenuator portion 33 is the thickest and the cylinder portion 32 is the thinnest (close to the first portions Q1, R1). The second point P2 is, for example, a point located near the portion of the exposed surface of the lens 5 where the attenuator portion 33 is the thinnest and the cylinder portion 32 is the thickest (close to the second portions Q2, R2). The "exposed surface of the lens 5" refers to the portion of the upper surface of the lens 5 that is exposed from the external vibrator 3, the internal vibrator 7, and the cover member 8.

[0064] 8 is a diagram showing the magnitude of displacement (amount of displacement) along a line connecting a first point P1 and a second point P2 on the exposed surface of the lens 5. As can be seen from Fig. 8, the amount of displacement (i.e., the amplitude of the lens 5) gradually increases from the second point P2 toward the first point P1. In this way, if the vibration device 1 is positioned so that the amplitude of the surface of the lens 5 gradually increases in the direction of gravity G (vertically downward), foreign matter on the surface of the lens 5 will easily slide off.

[0065] 2 , in this embodiment, the wiring 100 is connected to the piezoelectric element 9 from a position closer to the second external vibrating body 3R than to the first external vibrating body 3L, and a voltage is applied to the piezoelectric element 9 via the wiring 100. In this way, by connecting the wiring 100 from the side of the second external vibrating body 3R, which has a smaller amplitude, breakage of the wiring 100 and noise caused by vibration of the wiring 100 can be suppressed.

[0066] <Adjustment of Natural Vibration Frequency of External Vibrator 3> The dimensions of the attenuator portion 33 and the cylinder portion 32 can be adjusted so as to impart a desired gradient to the amplitude of the lens 5 .

[0067] 9A is a schematic cross-sectional view illustrating the natural vibration of only the internal vibrator. 9B and 9C are schematic cross-sectional views illustrating the natural vibration of only the external vibrator. In these figures, the stationary state is indicated by a solid line, and the vibrating state (state where the amplitude is maximum) is indicated by a dotted line.

[0068] 9A, when the internal vibrator 7 and the lens 5 are not connected to an external vibrator, they vibrate in the first direction Z due to expansion and contraction of the S-shaped lower portion 72. The resonant frequency is, for example, 22 to 29 kHz.

[0069] On the other hand, the natural vibration of only the external vibrator 3 can have, for example, two types of modes A and B shown in FIGS. 9B and 9C . Mode A, as shown in FIG. 9B , is a mode in which the amplitude of the first external vibrator 3L, including the first attenuator section and the first cylinder section, is smaller than the amplitude of the second external vibrator 3R, including the second attenuator section and the second cylinder section. Mode B, as shown in FIG. 9C , is a mode in which the amplitude of the first external vibrator 3L is larger than that of the second external vibrator 3R. By adjusting the frequencies (resonance frequencies) of the natural vibrations of these modes A and B, it is possible to couple either one of the modes with the natural vibration of the internal vibrator 7 ( FIG. 9A ). This makes it possible to impart a desired gradient to the amplitude of the lens 5 without increasing the resonant resistance value of the internal vibrator 7.

[0070] The frequencies of modes A and B of the natural vibration of the external vibrator 3 can be adjusted, for example, by the spring properties of the attenuator section 33 and the cylinder section 32. The spring properties of the attenuator section 33 and the cylinder section 32 can be adjusted, for example, by the following parameters, materials, etc. shown in FIG. 6A : t1, t2: thickness in the first direction Z of the first and second attenuator sections 331, 332 w1: width of the thick section 33a of the attenuator section 33 s1, s2: thickness in the second direction X of the first and second cylinder sections 321, 322 h: height in the Z direction of the cylinder section 32 u: distance along the second direction X between the outer surface of the cylinder section 32 and the outer surface of the attenuator section 33

[0071] In this embodiment, the frequency of Mode B is adjusted to a value closer to the resonant frequency of only the internal vibrator 7 (e.g., approximately 26 kHz) than the frequency of Mode A. As an example, the frequency of Mode A may be adjusted to 19.1 kHz, and the frequency of Mode B may be adjusted to 29.6 kHz. This allows the natural vibration of Mode B of the external vibrator 3 ( FIG. 9C ) to be coupled with the natural vibration of the internal vibrator 7 in the vibration device 1. In this case, the amplitude of the first external vibrator 3L, which has a thick attenuator section and a thin cylinder section, is greater than the amplitude of the second external vibrator 3R, which has a thin attenuator section and a thick cylinder section. Therefore, the amplitude of the region of the lens 5 located on the first external vibrator 3L side can be greater than the amplitude of the region of the lens 5 located on the second external vibrator 3R side.

[0072] (Effects) The vibration device 1 can exhibit the following effects.

[0073] The vibration device 1 includes a substantially cylindrical internal vibrator 7 extending in a first direction Z, a piezoelectric element 9 connected to one end of the internal vibrator 7 in the first direction Z, a light-transmitting body (here, a lens 5) connected to the other end of the internal vibrator 7 in the first direction Z and having an optical axis L extending along the first direction Z, and a substantially cylindrical external vibrator 3 extending in the first direction Z. The external vibrator 3 is arranged to surround the internal vibrator 7. The external vibrator 3 has a first connection portion 31 connected to the light-transmitting body, an attenuator portion 33 extending from the first connection portion 31 outward from the light-transmitting body along a second direction X intersecting the first direction Z, and a cylinder portion 32 connecting the first connection portion 31 and the attenuator portion 33 and extending along the first direction Z. The cylinder portion 32 is arranged at a distance from the internal vibrator 7 in the second direction X. At least one of the attenuator portion 33 and the cylinder portion 32 is asymmetric with respect to the optical axis.

[0074] According to the above configuration, at least one of the attenuator portion 33 and the cylinder portion 32 of the external vibrator 3 has non-axisymmetrical property, so that the amplitude of the light-transmitting body surface during vibration can be tilted. Therefore, it is possible to more effectively remove foreign matter adhering to the light-transmitting body surface. Furthermore, by suppressing uneven stress applied to the internal vibrator 7 during vibration, it is possible to suppress deterioration of impedance.

[0075] In this specification, the term "substantially cylindrical" refers to any shape having a hole penetrating in the extension direction (here, the first direction Z), and includes a substantially cylindrical shape, a substantially rectangular cylindrical shape, and the like. The cross section of the through hole of the substantially cylindrical body is, for example, a substantially circular shape such as a perfect circle or an ellipse. The outer shape of the substantially cylindrical body may be a cylindrical shape or a substantially polygonal prism shape such as a square prism. The substantially cylindrical body may include a cone-shaped portion or a stepped portion whose cross-sectional shape expands or contracts along the first direction Z. It is preferable that at least the portions of the internal vibrator 7 and the external vibrator 3 located on the lens 5 side are substantially cylindrical. This makes it possible to impart a desired inclination to the amplitude of the surface of the lens 5 while suppressing unnecessary vibrations.

[0076] In a cross-sectional view along the optical axis L, the attenuator section 33 has a first attenuator section 331 and a second attenuator section 332 positioned symmetrically with respect to the optical axis L, and the thickness t1 of the first attenuator section 331 in the first direction Z is different from the thickness t2 of the second attenuator section 332 in the first direction Z. With this configuration, the attenuator section 33 is given non-axial symmetry, while the external appearance of the vibration device 1 can be made symmetrical.

[0077] In a cross-sectional view along the optical axis L, the cylinder portion 32 has a first cylinder portion 321 and a second cylinder portion 322 positioned symmetrically with respect to the optical axis L, and the thickness s1 of the first cylinder portion 321 in the second direction X is different from the thickness s2 of the second cylinder portion 322 in the second direction X. With this configuration, the cylinder portion 32 is given non-axisymmetric properties, while the external appearance of the vibration device 1 can be made symmetrical.

[0078] Both the attenuator section 33 and the cylinder section 32 are non-axially symmetrical with respect to the optical axis. The attenuator section 33 is mainly involved in vibration along the first direction Z, and the cylinder section 32 is mainly involved in vibration along the second direction X. Therefore, since both the attenuator section 33 and the cylinder section 32 are non-axially symmetrical, it is easy to impart a desired tilt to the amplitude of the lens 5 by respectively setting the magnitude, direction, position, etc. of this non-axial symmetry.

[0079] In a cross-sectional view along the optical axis L, the first attenuator portion 331 and the first cylinder portion 321 are located on one side of the optical axis L, and the second attenuator portion 332 and the second cylinder portion 322 are located on the other side of the optical axis L. The thickness t1 of the first attenuator portion 331 in the first direction Z is greater than the thickness t2 of the second attenuator portion 332 in the first direction Z. The thickness s1 of the first cylinder portion 321 in the second direction X is smaller than the thickness s2 of the second cylinder portion 322 in the second direction X. In this way, by reversing the direction of the non-axisymmetric property of the cylinder portion 32 (here, the relationship between the thicknesses) and the non-axisymmetric property of the attenuator portion 33, the following effects can be obtained.

[0080] The inventors have found that the non-axial asymmetry of the attenuator unit 33 alone may make it difficult to impart a desired tilt to the amplitude of the lens 5. If the thickness t1 of the first attenuator unit 331 is too small, the amplitude of the lens 5 during vibration may not be greatest at the end of the lens 5 near the first attenuator unit 331. In other words, the position of the maximum displacement point of the lens 5 shifts from the end of the lens 5 toward the optical axis L (see FIG. 16 ). On the other hand, if the thickness t1 of the first attenuator unit 331 is too large, the vibration transmitted to the fixing unit 35 located below (opposite the lens 5) increases, reducing vibration efficiency during assembly of the camera module. In contrast, imparting non-axial asymmetry to the cylinder unit 32 in the opposite direction to the attenuator unit 33 can increase (e.g., maximize) the displacement of the end of the lens 5 near the first attenuator unit 331 (see FIG. 8 ). Therefore, the desired tilt can be imparted to the amplitude of the lens 5 while suppressing a decrease in vibration efficiency.

[0081] In a cross-sectional view along the optical axis L, the external vibrator 3 has a first external vibrator 3L and a second external vibrator 3R positioned symmetrically with respect to the optical axis L. When the amplitude of the first external vibrator 3L caused by vibrations generated by the piezoelectric element 9 is greater than the amplitude of the second external vibrator 3R caused by vibrations generated by the piezoelectric element 9, the second external vibrator 3R is positioned vertically above the first external vibrator 3L. With this configuration, the amplitude of the lens 5 surface is greater in a region positioned vertically below than in a region positioned vertically above. This makes it easier for foreign matter adhering to the surface of the translucent body to slide off due to vibration. If the amplitude on the lens 5 surface is inclined so that it gradually increases along the direction of gravity G, the sliding off of foreign matter can be further facilitated.

[0082] When the amplitude of the first external vibrator 3L caused by the vibration generated by the piezoelectric element 9 is larger than the amplitude of the second external vibrator 3R caused by the vibration generated by the piezoelectric element 9, the wiring 100 is connected to the piezoelectric element 9 from a position closer to the second external vibrator 3R than to the first external vibrator 3L. With this configuration, breakage of the wiring 100 and noise caused by the vibration of the wiring 100 can be suppressed.

[0083] The internal vibrator 7 is axially symmetric with respect to the optical axis. With this configuration, the internal vibrator 7 does not have a non-axisymmetric structure, making it difficult for unwanted vibrations caused by the structure of the internal vibrator 7 to occur. This makes it possible to further suppress the superposition of unwanted vibrations of the internal vibrator 7. This also makes it possible to further suppress the deterioration of impedance. Furthermore, by minimizing the uneven distribution of stress applied to the internal vibrator 7 during vibration, it is possible to further suppress the deterioration of impedance.

[0084] The piezoelectric element 9 has axial symmetry with respect to the optical axis L. With this configuration, unwanted vibrations due to the structure of the piezoelectric element 9 are less likely to occur. This makes it possible to suppress the superposition of unwanted vibrations of the internal vibrator 7. This makes it possible to further suppress the deterioration of impedance.

[0085] The vibration device 1 can be configured as follows.

[0086] 6B, the thick portion 33a of the attenuator section 33 extends in the circumferential direction across the first attenuator section 331, but as illustrated in Figures 10A and 10B, the thick portion 33a may be located in only a part of the first attenuator section 331. In this example, the thick portion 33a includes an arched portion along part of the outer edge of the first attenuator section 331 in a plan view seen from the -Z direction.

[0087] The dimensions (FIG. 4) of the attenuator section 33 and the cylinder section 32 may be adjusted to couple the natural vibration of mode A (FIG. 9B) of the external vibrator 3 with the natural vibration of the internal vibrator 7. In this case, the amplitude of the first external vibrator 3L becomes smaller than the amplitude of the second external vibrator 3R. Such a configuration can be realized, for example, by reducing the height h of the cylinder section 32.

[0088] The non-axisymmetric nature of the attenuator portion 33 and / or the cylinder portion 32 is not limited to the case where the thickness (wall thickness) is different. Also, only one of the attenuator portion 33 and the cylinder portion 32 may have non-axisymmetric nature.

[0089] (Modifications) Modifications of the vibration device will be described below. According to the following modifications 1 to 3, it is possible to impart a tilt to the amplitude of the lens without impairing the axial symmetry of the internal vibrating body, as with the vibration device 1 shown in FIG.

[0090] <Modification 1> Fig. 11 is a schematic cross-sectional view showing a vibration device of Modification 1. Fig. 12A is a schematic cross-sectional view showing an external vibrator in the vibration device of Fig. 11 excluding the fixed portion. Fig. 12B is a cross-sectional view taken along line XIIB-XIIB in Fig. 12A. Fig. 13 is a perspective view showing an example of the arrangement of the vibration device of Fig. 11. Fig. 14 is a graph illustrating the amount of displacement of the surface of lens 5 of the vibration device of Fig. 11.

[0091] In the vibration device 1a, the cylinder portion 32 is asymmetrical with respect to the optical axis L. Specifically, the thickness s2 of the second cylinder portion 322 is greater than the thickness s1 of the first cylinder portion 321. On the other hand, the attenuator portion 33 is symmetrical with respect to the optical axis L. The thickness t of the attenuator portion 33 is, for example, approximately uniform around the entire circumference.

[0092] 12A and 12B , in this modification, the cylinder portion 32 includes a main portion 324 formed integrally with the attenuator portion 33 and a weight member 325. The main portion 324 has, for example, a substantially uniform thickness s1 around its entire circumference. The weight member 325 is located inside the main portion 324 in the second cylinder portion 322 and contacts the inner surface of the main portion 324. The weight member 325 has, for example, a semi-cylindrical shape extending in the first direction Z. The thickness s2 of the second cylinder portion 322 in the second direction X is the total thickness of the main portion 324 and the weight member 325. Therefore, the thickness s2 is greater than the thickness s1 of the first cylinder portion 321 by the thickness of the weight member 324.

[0093] The weight member 325 may be made of the same material as that of the attenuator section 33, or may be made of a different material. The elastic modulus of the material of the weight member 325 may be greater than the elastic modulus of the material of the attenuator section 33. This allows the amplitude of the lens 5 to be tilted more efficiently.

[0094] In the illustrated example, the weight member 325 is disposed across the height of the main portion 324 in the first direction Z. As shown in Fig. 12A , the weight member 325 and the main portion 324 extend in the first direction Z up to the upper surface of the attenuator portion 33. Therefore, the cylinder portion 32 does not have an inclined portion as shown in Fig. 2 . Note that the height of the weight member 325 in the first direction Z may be smaller than the height of the main portion 324.

[0095] The vibration device 1a of this modified example is configured, for example, so that the amplitude of the second external vibrator 3R including the second cylindrical portion 322 is smaller than the amplitude of the first external vibrator 3L including the first cylindrical portion 321. In this case, as shown in FIG. 13 , the vibration device 1a is positioned so that the second external vibrator 3R is on the upper side in the vertical direction. This allows the amplitude of vibration to gradually increase from a second point P2 located at the upper end of the lens 5 to a first point P1 located at the lower end, for example, as shown in FIG. 14 . The first point P1 may be, for example, a point on the exposed surface of the lens 5 that is close to the center point of the weight member 325 in the circumferential direction.

[0096] In this modification, the first cylinder portion 321 is composed of a portion of the main portion 324 (also referred to as the "first member"), and the second cylinder portion 322 is composed of another portion of the main portion 324 and a weight member 325 (also referred to as the "second member"). The weight member 325 is located inside the main portion 324. The weight member 325 may be made of the same material as or different from the material of the main portion 324. This configuration allows the cylinder portion 32 to be non-axially symmetrical while maintaining a symmetrical appearance for the vibration device 1. Furthermore, the attenuator portion 33 (first attenuator portion 331) can be thinner than the vibration device 1 shown in FIG. 2. This allows for attenuation of vibrations propagating from the attenuator portion 33 to the fixed portion 35. The thickness of the cylinder portion may be varied in parts without providing a separate member such as the weight member 325 (see FIG. 2).

[0097] <Modification 2> Fig. 15 is a schematic cross-sectional view of a vibration device of Modification 2. Fig. 16 is a schematic graph illustrating the amount of displacement of the lens surface of the vibration device of Fig. 15 .

[0098] In the vibration device 1b, the attenuator section 33 is asymmetrical about the optical axis L. For example, similar to the vibration device 1 shown in FIG. 2, the thickness t1 of the first attenuator section 331 is greater than the thickness t2 of the second attenuator section 332. The attenuator section 33 has a thick section 33a and a thin section 33b, similar to the configurations illustrated in FIG. 6B or 13B, for example. On the other hand, the cylinder section 32 is symmetrical about the optical axis L. The thickness s of the cylinder section 32 is, for example, approximately uniform around the entire circumference. With this configuration, the attenuator section 33 is asymmetrical about the optical axis L while the external appearance of the vibration device 1 can be made symmetrical.

[0099] The vibration device 1b of this modified example is configured so that the amplitude of the first external vibrator 3L including the first attenuator section 331 is larger than the amplitude of the second external vibrator 3R including the second attenuator section 332. In this case, the vibration device 1b is arranged, for example, so that the first portion Q1 (FIG. 6B) of the first attenuator section 331 is on the lower side in the vertical direction and the second portion Q2 (FIG. 6B) of the second attenuator section 332 is on the upper side in the vertical direction. This makes it possible to make the amplitude of a first point P1 located at the lower end larger than the amplitude of a second point P2 located at the upper end of the lens 5, for example, as shown in FIG. 16 .

[0100] 16 , the maximum displacement point P3, where the displacement amount is greatest, is located closer to the second point P2 than the first point P1 on the exposed surface of the lens 5. If the first attenuator section 331 is made thicker, the maximum displacement point P3 can be moved closer to the first point P1. However, if the attenuator section 33 is made thicker, the vibration transmitted from the attenuator section 33 to the fixed section 35 below tends to increase, which may reduce vibration efficiency. For this reason, in this modification, the thickness t1 of the first attenuator section 331 is adjusted to move the maximum displacement point P3 as close as possible to the first point P1 (the lower end of the lens 5) while ensuring vibration efficiency, thereby facilitating the sliding of foreign matter.

[0101] The vibration device 1b may be configured so that the amplitude of the first attenuator section 331 is smaller than the amplitude of the second attenuator section 332. Such a configuration can be achieved by adjusting the dimensions, for example, by reducing the height h of the cylinder section 32.

[0102] <Modification 3> Fig. 17 is a schematic perspective view of a vibration device of Modification 3. Fig. 18 is a cross-sectional view taken along line XVIII-XVIII in Fig. 17 .

[0103] In the vibration device 1c, the first attenuator portion 331 and the first cylindrical portion 321 are made of different materials from the second attenuator portion 332 and the second cylindrical portion 322. The attenuator portion 33 and the cylindrical portion 32 may both be axially symmetric with respect to the optical axis L. With this configuration, the appearance of the vibration device 1 can be made symmetrical while imparting non-axial symmetry to the attenuator portion 33 and the cylindrical portion 32.

[0104] 17 and 18 , the portions of the external vibrator 3 excluding the fixing portion 35 are formed from two types of materials. In detail, the first connecting portion 31, the cylinder portion 32 (first cylinder portion 321), the attenuator portion 33 (first attenuator portion 331), and the second connecting portion 34 that constitute the first external vibrator 3L are made from a first material. The first connecting portion 31, the cylinder portion 32 (second cylinder portion 322), the attenuator portion 33 (second attenuator portion 332), and the second connecting portion 34 that constitute the second external vibrator 3R are made from a second material that is different from the first material.

[0105] For example, materials with different elastic moduli (Young's moduli) can be selected as the first and second materials. As an example, if the elastic modulus of the second material is greater than that of the first material, the amplitude of the second external vibrator 3R made of the second material will be smaller than the amplitude of the first external vibrator 3L made of the first material. In this case, the vibration device 1c is arranged, for example, so that the second external vibrator 3R is positioned vertically above the first external vibrator 3L.

[0106] In this modification, both the attenuator portion 33 and the cylinder portion 32 are made of two types of material, but only one of the attenuator portion 33 and the cylinder portion 32 may be made of two types of material. Also, in this modification, the elastic moduli of the first material and the second material are made different, but, for example, the densities or mechanical Q values ​​may be made different. Furthermore, as long as at least one of the attenuator portion 33 and the cylinder portion 32 is given non-axisymmetric properties, the types and numbers of materials used, the arrangement and proportions of each material, etc. are not particularly limited.

[0107] The configuration of the vibration device of the present invention is not limited to the configuration described above with reference to Figures 1 to 18. In these figures, the attenuator section 33 and the cylinder section 32 are integrally formed, but they may be formed as separate members.

[0108] The non-axial symmetry of the attenuator portion 33 and the cylinder portion 32 may be imparted by combining any of the above-described configurations. For example, both the material and the thickness of the attenuator portion 33 and / or the cylinder portion 32 may be made different from each other.

[0109] Any of the various embodiments or modifications described above can be combined appropriately to achieve the effects of each. In addition, combinations of embodiments, combinations of examples, or combinations of embodiments and examples are possible, and combinations of features from different embodiments or examples are also possible.

[0110] Although the present invention has been described in various embodiments with a certain degree of detail, the disclosure of these embodiments may vary in structural details, and variations in the combination and order of elements in the various embodiments may be realized without departing from the scope and spirit of the invention as claimed.

[0111] The vibration device of the present invention can remove foreign matter adhering to a light-transmitting body, and therefore can be applied to an imaging unit or the like.

[0112] DESCRIPTION OF SYMBOLS 1, 1a, 1b, 1c Vibration device 3 External vibrator 3L First external vibrator 3R Second external vibrator 5 Lens 7 Internal vibrator 8 Cover member 9 Piezoelectric element 31 First connection portion 32 Cylinder portion 33 Attenuator portion 33a Thick portion 33b Thin portion 34 Second connection portion 35 Fixing portion 41 Upper cylindrical body 42 Lower cylindrical body 51 Flat portion 52 Recessed portion 53 Top surface 71 Upper portion 72 Lower portion 73 Middle portion 100 Wiring 321 First cylinder portion 322 Second cylinder portion 324 Main portion 325 Weight member 331 First attenuator portion 332 Second attenuator portion 711 Plate-like portion 712 Protruding portion L Optical axis Q1, Q2 Attenuator section R1, R2 Cylinder section P1 First point P2 Second point

Claims

1. A vibration device comprising: a generally cylindrical internal vibrator capable of amplifying vibrations and extending in a first direction; a piezoelectric element connected to one end of the internal vibrator in the first direction and capable of generating vibrations; a translucent body connected to the other end of the internal vibrator in the first direction and having an optical axis extending along the first direction; and a generally cylindrical external vibrator arranged to surround the internal vibrator and extend in the first direction, wherein the external vibrator has a first connection portion connected to the translucent body; an attenuator portion extending from the first connection portion to the outside of the translucent body along a second direction intersecting the first direction and configured to attenuate vibrations; and a cylinder portion connecting the first connection portion and the attenuator portion and extending along the first direction, wherein the cylinder portion is arranged at a distance from the internal vibrator in the second direction, and at least one of the attenuator portion and the cylinder portion is non-axially symmetrical with respect to the optical axis.

2. The vibration device described in claim 1, wherein, in a cross-sectional view along the optical axis, the attenuator section has a first attenuator section and a second attenuator section positioned symmetrically with respect to the optical axis, and the thickness of the first attenuator section in the first direction is different from the thickness of the second attenuator section in the first direction.

3. A vibration device as described in claim 1 or 2, wherein, in a cross-sectional view along the optical axis, the cylinder portion has a first cylinder portion and a second cylinder portion positioned symmetrically with respect to the optical axis, and the thickness of the first cylinder portion in the second direction is different from the thickness of the second cylinder portion in the second direction.

4. The vibration device as described in claim 3, wherein the cylinder portion has a first member and a second member, the first cylinder portion is constituted by a part of the first member, the second cylinder portion is constituted by another part of the first member and the second member, and in the second cylinder portion, the second member is located inside the first member.

5. A vibration device according to any one of claims 1 to 4, wherein both the attenuator section and the cylinder section are non-axially symmetric with respect to the optical axis.

6. The vibration device described in claim 5, wherein, in a cross-sectional view along the optical axis, the attenuator section has a first attenuator section and a second attenuator section positioned symmetrically with respect to the optical axis, the cylinder section has a first cylinder section and a second cylinder section positioned symmetrically with respect to the optical axis, the first attenuator section and the first cylinder section are positioned on one side of the optical axis, and the second attenuator section and the second cylinder section are positioned on the other side of the optical axis, the thickness of the first attenuator section in the first direction is greater than the thickness of the second attenuator section in the first direction, and the thickness of the first cylinder section in the second direction is smaller than the thickness of the second cylinder section in the second direction.

7. A vibration device as described in any one of claims 1 to 6, wherein, in a cross-sectional view along the optical axis, the attenuator section has a first attenuator section and a second attenuator section positioned symmetrically with respect to the optical axis, and a material constituting the first attenuator section is different from a material constituting the second attenuator section.

8. A vibration device as described in any one of claims 1 to 7, wherein, in a cross-sectional view along the optical axis, the cylinder portion has a first cylinder portion and a second cylinder portion positioned symmetrically with respect to the optical axis, and the first cylinder portion is made of a different material than the second cylinder portion.

9. A vibration device as described in any one of claims 1 to 8, wherein, in a cross-sectional view along the optical axis, the external vibrator has a first external vibrator and a second external vibrator positioned symmetrically with respect to the optical axis, and when the amplitude of the first external vibrator due to vibration generated in the piezoelectric element is larger than the amplitude of the second external vibrator due to vibration generated in the piezoelectric element, the second external vibrator is positioned vertically above the first external vibrator.

10. A vibration device according to any one of claims 1 to 9, wherein the internal vibrator has axial symmetry with respect to the optical axis.

11. A vibration device according to any one of claims 1 to 10, wherein the piezoelectric element has axial symmetry with respect to the optical axis.

12. A vibration device as described in any one of claims 1 to 11, wherein, in a cross-sectional view along the optical axis, the external vibration body has a first external vibration body and a second external vibration body positioned symmetrically with respect to the optical axis, and when the amplitude of the first external vibration body due to vibration generated in the piezoelectric element is larger than the amplitude of the second external vibration body due to vibration generated in the piezoelectric element, wiring is connected to the piezoelectric element from a position closer to the second external vibration body than the first external vibration body.

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