Vibration device

Abstract

This vibration device comprises: a vibrator; a piezoelectric element positioned at one end of the vibrator in a first direction; and a translucent body that has an optical axis extending in the first direction and that is positioned at the other end of the vibrator in the first direction. The vibrator includes a first flange connected to the translucent body, a second flange connected to the piezoelectric element, and an arm that connects the first flange and the second flange. The first and second flanges extend, in a cross-section including the optical axis, along a direction approaching the optical axis in a second direction, which intersects the first direction, from positions away from the optical axis in the second direction. The arm has a curved shape in the cross-section including the optical axis.

Description

vibration device

[0001] The present disclosure relates to vibration devices.

[0002] Patent document 1 discloses a vibration device that includes a vibrator having a cylindrical vibrating body provided with a light-transmitting body, a support body that supports the vibrating body, and a connecting member that connects the vibrating body and the support body.

[0003] Patent No. 7010386

[0004] The vibration device of Patent Document 1 has room for improvement in terms of reducing the stress applied to the light-transmitting body while preventing foreign matter adhering to the light-transmitting body from accumulating on the vibrating body.

[0005] An object of the present disclosure is to provide a vibration device that can reduce stress on a light-transmitting body while preventing foreign matter adhering to the light-transmitting body from accumulating on the vibrating body.

[0006] A vibration device according to one aspect of the present disclosure comprises a vibrating body, a piezoelectric element located at one end of the vibrating body in a first direction, and a translucent body having an optical axis extending along the first direction and located at the other end of the vibrating body in the first direction, wherein the vibrating body includes a first flange portion connected to the translucent body, a second flange portion connected to the piezoelectric element, and an arm portion connecting the first flange portion and the second flange portion, wherein the first flange portion and the second flange portion extend in a cross section including the optical axis from a position away from the optical axis in a second direction intersecting the first direction, along the second direction and a direction approaching the optical axis, and the arm portion has a curved shape in the cross section.

[0007] According to the vibration device of the above aspect, it is possible to reduce the stress acting on the light-transmitting body while preventing foreign matter adhering to the light-transmitting body from accumulating on the vibrating body.

[0008] 1 is a perspective view showing a vibration device according to an embodiment of the present disclosure. FIG. 1 is a cross-sectional view taken along line II-II in FIG. 1. FIG. 2 is a diagram showing a simulation result of displacement distribution in the vibration device of FIG. 1. FIG. 3 is a diagram showing a simulation result of stress distribution in the vibration device of FIG. 1. FIG. 4 is a cross-sectional view showing an example of a vibration device not including the vibration body of the vibration device of FIG. 1. FIG. 5 is a diagram showing a simulation result of displacement distribution in the vibration device of FIG. 5. FIG. 6 is a diagram showing a simulation result of stress distribution in the vibration device of FIG. 5. A graph comparing the stress applied to the joint between the lens and the vibration body of the vibration device of FIG. 1 with the stress applied to the joint between the lens and the vibration body of the vibration device of FIG. 5. A perspective view showing an example of a usage mode of the vibration device of FIG. 1. A perspective view showing an example of a usage mode of the vibration device of FIG. 5. A graph showing the relationship between the ratio of the first distance to the second distance and the stress applied to the joint between the lens and the first flange portion.

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

[0010] A vibration device of a first aspect of the present disclosure comprises a vibrating body, a piezoelectric element located at one end of the vibrating body in a first direction, and a translucent body having an optical axis extending along the first direction and located at the other end of the vibrating body in the first direction, wherein the vibrating body includes a first flange portion connected to the translucent body, a second flange portion connected to the piezoelectric element, and an arm portion connecting the first flange portion and the second flange portion, wherein the first flange portion and the second flange portion extend in a cross section including the optical axis from a position away from the optical axis in a second direction intersecting the first direction, along the second direction and a direction approaching the optical axis, and the arm portion has a curved shape in the cross section.

[0011] According to the vibration device of the first aspect, the peeling stress applied to the joint between the light-transmitting body and the vibrating body can be significantly reduced, thereby reducing the stress applied to the light-transmitting body when the vibrating body vibrates and suppressing deterioration of optical characteristics. The curved shape of the arm portion can suppress the accumulation of foreign matter such as raindrops and muddy water on the vibrating body. In other words, according to the vibration device of the first aspect, the stress applied to the light-transmitting body can be reduced while preventing foreign matter adhering to the light-transmitting body from accumulating on the vibrating body.

[0012] A vibration device of a second aspect of the present disclosure is the vibration device of the first aspect, wherein the arm portion includes: a first arm portion extending from one of the ends of the first flange portion in the second direction that is farther from the optical axis toward the second flange portion; and a second arm portion extending from one of the ends of the second flange portion in the second direction that is farther from the optical axis toward the first flange portion and connected to the end of the first arm portion opposite the end connected to the first flange portion.

[0013] According to the vibration device of the second aspect, it is possible to more reliably prevent foreign matter adhering to the light-transmitting body from accumulating on the vibrating body, and to more reliably reduce the stress acting on the light-transmitting body.

[0014] A third aspect of the vibration device of the present disclosure is the vibration device of the second aspect, wherein the distance in the first direction from the portion of the first flange portion that contacts the translucent body to the connection portion of the first arm portion and the second arm portion is defined as a first distance, and the total length of the arm portion in the first direction is defined as a second distance, and the ratio of the second distance to the first distance is 0.05 or more.

[0015] According to the vibration device of the third aspect, the stress applied to the light-transmitting body can be further reduced.

[0016] A vibration device of a fourth aspect of the present disclosure is the vibration device of any one of the first to third aspects, further comprising a holding member positioned outside the translucent body in the second direction and holding the connection between the translucent body and the first flange portion.

[0017] According to the vibration device of the fourth aspect, the holding member can prevent the light-transmitting body from falling off the vibration body. For example, by configuring the holding member to be light-blocking, it is possible to block light incident from the side surface of the light-transmitting body, thereby reducing the occurrence of stray light, ghosts, flare, etc.

[0018] A vibration device according to a fifth aspect of the present disclosure is the vibration device according to the fourth aspect, wherein the holding member is asymmetric with respect to the optical axis.

[0019] According to the vibration device of the fifth aspect, foreign matter adhering to the light-transmitting body can be more reliably slid off.

[0020] A vibration device of a sixth aspect of the present disclosure is a vibration device of any one of the first to fifth aspects, wherein the cross section of the first arm portion has a curved shape that protrudes from the first flange portion toward the second flange portion, and the cross section of the second arm portion has a curved shape that protrudes from the second flange portion toward the first flange portion.

[0021] According to the vibration device of the sixth aspect, it is possible to more reliably prevent foreign matter adhering to the light-transmitting body from accumulating on the vibrating body, and to more reliably reduce the stress acting on the light-transmitting body.

[0022] A seventh aspect of the present disclosure provides the vibration device of the sixth aspect, wherein the radius of curvature of the curved shape of the first arm portion is greater than the radius of curvature of the curved shape of the second arm portion.

[0023] According to the vibration device of the seventh aspect, it is possible to more reliably prevent foreign matter adhering to the light-transmitting body from accumulating on the vibrating body, and to more reliably reduce the stress acting on the light-transmitting body.

[0024] An eighth aspect of the present disclosure provides a vibration device according to any one of the first to seventh aspects, wherein the arm portion extends along the optical axis.

[0025] According to the vibration device of the eighth aspect, it is possible to more reliably prevent foreign matter adhering to the light-transmitting body from accumulating on the vibrating body, and to more reliably reduce the stress acting on the light-transmitting body.

[0026] A ninth aspect of the present disclosure provides a vibration device according to any one of the first to eighth aspects, wherein the thickness of the second flange portion is greater than the thickness of the first flange portion.

[0027] According to the vibration device of the ninth aspect, the vibration of the piezoelectric element can be efficiently transmitted to the light-transmitting body.

[0028] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The following description does not limit the present disclosure, but is essentially merely illustrative, and appropriate modifications can be made without departing from the spirit of the present disclosure. The drawings are schematic, and the ratios of dimensions and the like do not necessarily correspond to reality.

[0029] 1 , a vibration device 1 according to an embodiment of the present disclosure includes a vibrating body 10, a piezoelectric element 20 located at one end of the vibrating body 10 in a first direction (e.g., the Z direction), and a lens 30 (an example of a translucent body) located at the other end of the vibrating body 10 in the first direction Z. The lens 30 has an optical axis L extending along the first direction Z.

[0030] As an example, the vibrating body 10 has a substantially cylindrical shape and is configured to amplify vibrations from the piezoelectric element 20 to vibrate the lens 30. In this embodiment, as shown in Fig. 2, the vibrating body 10 includes a first flange portion 11 connected to the lens 30, a second flange portion 12 connected to the piezoelectric element 20, and an arm portion 13 connecting the first flange portion 11 and the second flange portion 12.

[0031] 2 , in a cross section including the optical axis L, the first flange portion 11 and the second flange portion 12 extend from a position away from the optical axis L in a second direction (e.g., the X direction) intersecting the first direction Z along the second direction X and a direction approaching the optical axis L. In the present embodiment, the first flange portion 11 and the second flange portion 12 have a substantially annular shape extending in a circumferential direction about the optical axis L. The second direction X is an example of a radial direction about the optical axis L. The first flange portion 11 extends from an end 301 of the lens 30 in the second direction X toward the optical axis L along the second direction X. The second flange portion 12 extends from a position farther from the optical axis L than the end 301 of the lens 30 in the second direction X toward the optical axis L along the second direction X.

[0032] The arm portion 13 has a curved shape in a cross section including the optical axis L. In this embodiment, the arm portion 13 includes a first arm portion 131 and a second arm portion 132. The arm portion 13 extends along the optical axis L and has a substantially S-shape in a cross section including the optical axis L. The radius of curvature of the curved shape of the first arm portion 131 is larger than the radius of curvature of the curved shape of the second arm portion 132.

[0033] In a cross section including the optical axis L, the first arm portion 131 extends from an end 1101 of the first flange portion 11 in the second direction X that is farther from the optical axis L toward the second flange portion 12. The cross section of the first arm portion 131 including the optical axis L has a curved shape that protrudes from the first flange portion 11 toward the second flange portion 12.

[0034] The second arm portion 132 extends from an end 1201 of the second flange portion 12 farther from the optical axis L than the other end in the second direction X toward the first flange portion 11, and is connected to the end of the first arm portion 131 opposite to the end connected to the first flange portion 11. A cross section of the second arm portion 132 including the optical axis L has a curved shape that protrudes from the second flange portion 12 toward the first flange portion 11.

[0035] In this embodiment, the first arm portion 131 and the second arm portion 132 are connected at a portion where a tangent L1 to the outline of the arm portion 13 in a cross section including the optical axis L extends along the second direction X. That is, at a connection portion 133 between the first arm portion 131 and the second arm portion 132, the tangent L1 extends approximately parallel to the second direction X. The vibrating body 10 is configured so that the thickness T2 of the second flange portion 12 is greater than the thickness T1 of the first flange portion 11. The thicknesses T1 and T2 of the first flange portion 11 and the second flange portion 12 are, for example, the average values ​​of the dimensions of the first flange portion 11 and the second flange portion 12 in the first direction Z.

[0036] The piezoelectric element 20 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 ３The electrodes are made of, for example, Ni, Ag, or Au.

[0037] In this embodiment, the piezoelectric element 20 has a substantially annular shape extending in the circumferential direction about the optical axis L, and is positioned symmetrically about the optical axis L. The piezoelectric element 20 is connected to the second flange portion 12 by, for example, an adhesive.

[0038] The lens 30 is made of glass, for example, and has a substantially circular shape when viewed along the first direction Z. The lens 30 is curved in the first direction Z so as to protrude in a direction away from the vibrating body 10. A surface 302 of the lens 30 is coated with a water-repellent coating and an anti-reflection coating (AR coating). An end 301 of the lens 30 in the second direction X is provided with a protrusion 303 that protrudes radially outward relative to the optical axis L.

[0039] In this embodiment, the vibration device 1 includes a holding member 40. The holding member 40 is located outside the lens 30 in the second direction X and is configured to maintain the connection between the lens 30 and the first flange portion 11. As an example, the holding member 40 has a substantially annular shape extending along the edge of the lens 30 when viewed along the first direction Z. The holding member 40 extends from the lens 30 to the first flange portion 11 along the first direction Z in a cross section including the optical axis L. The connection portion between the lens 30 and the first flange portion 11 is covered by the holding member 40.

[0040] Of both ends of the holding member 40 in the first direction Z, a pressing portion 41 is provided on the end farther from the first flange portion 11. The pressing portion 41 protrudes from the holding member 40 toward the lens 30. A protruding portion 303 of the lens 30 is located between the pressing portion 41 and the first flange portion 11 in the first direction Z. This prevents the lens 30 from falling off the vibrating body 10.

[0041] Fig. 3 shows the simulation results of the displacement distribution of the vibration device 1 when the piezoelectric element 20 is driven. Fig. 4 shows the simulation results of the stress distribution around the joint 50 between the lens 30 and the vibrating body 10 of the vibration device 1. Fig. 6 shows the simulation results of the displacement distribution of the vibration device 100 (shown in Fig. 5) that does not include the vibrating body 10 when the piezoelectric element 120 is driven. Fig. 7 shows the simulation results of the stress distribution around the joint 150 between the lens 130 and the vibrating body 110 of the vibration device 100.

[0042] Simulations were performed assuming that the vibration device 100 has the same configuration as the vibration device 1, except for the vibration body 110, i.e., the piezoelectric element 120, the lens 130, and the holding member 140. The vibration body 110 includes a first flange portion 111, a second flange portion 112, and a connecting portion 113, and does not have a curved shape in a cross section including the optical axis L. The first flange portion 111 extends in a direction substantially perpendicular to the optical axis L and is connected to the lens 130. The second flange portion 112 extends in a direction substantially perpendicular to the optical axis L and is connected to the piezoelectric element 120. The connecting portion 113 extends linearly in the first direction Z in a cross section including the optical axis L, and connects the portion of the first flange portion 111 farthest from the optical axis L to the portion of the second flange portion 112 farthest from the optical axis L.

[0043] As shown in Fig. 3, in the vibration device 1, the lens 30 moves in the vertical direction (i.e., the first direction Z). That is, in the vibration device 1, a vertical displacement is input from the vibrating body 10 to the lens 30 due to vibrations generated by the piezoelectric element 30. As shown in Fig. 6, in the vibration device 100, the lens 130 moves not only in the vertical direction but also in a direction intersecting the vertical direction.

[0044] As shown in Fig. 4, in the vibration device 1, stress is applied to a portion of the lens 30 around the joint 50. As shown in Fig. 7, in the vibration device 100, stress is applied not only to the area around the joint 150 but also over a wide area of ​​the lens 130.

[0045] 8 is a graph comparing the stress applied to the joint 50 of the vibration device 1 with the stress applied to the joint 150 of the vibration device 100. As shown in Fig. 8, the stress applied to the joint 150 of the vibration device 100 is about nine times the stress applied to the joint 50 of the vibration device 1. In other words, it can be seen that the vibration device 1 can significantly reduce the peel stress applied to the joint between the lens 30 and the vibration body 10 compared to the vibration device 100.

[0046] FIG. 9 shows an example of how the vibration device 1 is used. FIG. 10 shows an example of how the vibration device 100 is used. In FIGS. 9 and 10 , the up-down direction is assumed to be vertical. As shown in FIG. 9 , even if a droplet 200 adheres to the vibration body 10, the curved shape of the arm portion 13 promotes the droplet 200 to slide off the vibration body 10, making it difficult for a droplet pool to form on the vibration body 10. As shown in FIG. 10 , when a droplet 200 adheres to the vibration device 100, the droplet 200 is trapped in the right-angle portion 160 formed by the holding member 140 and the vibration body 110, making it easier for a droplet pool to form than with the vibration device 1. In other words, the vibration device 1 can suppress the accumulation of foreign matter such as raindrops and muddy water on the vibration body 10 compared to the vibration device 100.

[0047] The vibration device 1 can achieve the following effects.

[0048] The vibration device 1 includes a vibrating body 10, a piezoelectric element 20 located at one end of the vibrating body 10 in a first direction, and a lens 30 located at the other end of the vibrating body 10 in the first direction, the lens 30 having an optical axis L extending along the first direction. The vibrating body 10 includes a first flange portion 11 connected to the lens 30, a second flange portion 12 connected to the piezoelectric element 20, and an arm portion 13 connecting the first flange portion 11 and the second flange portion 12. In a cross section including the optical axis L, the first flange portion 11 and the second flange portion 12 extend from a position away from the optical axis L in a second direction intersecting the first direction to a direction approaching the optical axis L in the second direction. The arm portion 13 has a curved shape in the cross section including the optical axis L. This configuration significantly reduces peel stress applied to the joint between the lens 30 and the vibrating body 10, thereby reducing stress applied to the lens 30 when the vibrating body 10 vibrates and suppressing deterioration of optical characteristics. The curved shape of the arm portion 13 can prevent foreign matter such as raindrops and muddy water from accumulating on the vibrating body 10. In other words, the vibration device 1 can reduce the stress on the lens 30 while preventing foreign matter adhering to the lens 30 from accumulating on the vibrating body 10.

[0049] The arm portion 13 includes a first arm portion 131 and a second arm portion 132. The first arm portion 131 extends from an end 1101, of both ends of the first flange portion 11 in the second direction, that is farther from the optical axis L, toward the second flange portion 12. The second arm portion 132 extends from an end 1201, of both ends of the second flange portion 12 in the second direction, that is farther from the optical axis L, toward the first flange portion 11, and is connected to an end of the first arm portion 131 opposite to the end connected to the first flange portion 11. With this configuration, foreign matter adhering to the lens 30 can be more reliably prevented from accumulating on the vibrating body 10, while more reliably reducing the stress acting on the lens 30.

[0050] The ratio of the second distance H2 to the first distance H1 is equal to or greater than 0.05. With this configuration, the stress applied to the lens 30 can be further reduced.

[0051] The vibration device 1 includes a holding member 40 that is positioned outside the lens 30 in the second direction and that maintains the connection between the lens 30 and the first flange portion 11. This configuration can prevent the lens 30 from falling off the vibration body 10. For example, by configuring the holding member 40 to be light-blocking, it is possible to block light that enters from the side surface of the lens 30, thereby reducing the occurrence of stray light, ghosts, flare, and the like.

[0052] A cross section including the optical axis L of the first arm portion 131 has a curved shape that protrudes from the first flange portion 11 toward the second flange portion 12. A cross section including the optical axis L of the second arm portion 132 has a curved shape that protrudes from the second flange portion 12 toward the first flange portion 11. With this configuration, it is possible to more reliably prevent foreign matter adhering to the lens 30 from accumulating on the vibrating body 10, while more reliably reducing the stress acting on the lens 30.

[0053] The radius of curvature of the curved shape of the first arm portion 131 is larger than the radius of curvature of the curved shape of the second arm portion 132. With this configuration, it is possible to more reliably prevent foreign matter adhering to the lens 30 from accumulating on the vibrating body 10, while more reliably reducing the stress acting on the lens 30.

[0054] The arm portion 13 extends along the optical axis L. With this configuration, it is possible to more reliably prevent foreign matter adhering to the lens 30 from accumulating on the vibrating body 10, and to more reliably reduce the stress acting on the lens 30.

[0055] The thickness T2 of the second flange portion 12 is greater than the thickness T1 of the first flange portion 11. With this configuration, the vibration of the piezoelectric element 20 can be transmitted to the lens 30 efficiently.

[0056] The vibration device 1 can also be configured as follows.

[0057] The distance in the first direction Z from the portion 1102 of the first flange portion 11 that contacts the lens 30 to the connection portion 133 of the first arm portion 131 and the second arm portion 132 is defined as a first distance H1 (see FIG. 2). The total length of the arm portion 13 in the first direction Z is defined as a second distance H2 (see FIG. 2). The vibrating body 10 may be configured so that the ratio of the first distance H1 to the second distance H2 is 0.05 or greater (H1 / H2≧0.05).

[0058] 11 shows the relationship between the ratio of the first distance H1 to the second distance H2 and the stress applied to the joint between the lens 30 and the first flange portion 11. As shown in FIG. 11, as the ratio of the first distance H1 to the second distance H2 decreases, the stress applied to the joint between the lens 30 and the first flange portion 11 increases. By configuring the vibrating body 10 so that H1 / H2≧0.05, the stress applied to the joint between the lens 30 and the first flange portion 11 is reduced to approximately half or less of the stress applied to the joint between the lens 130 and the vibrating body 110 of the vibration device 100 shown in FIG. 5. In other words, by configuring the vibrating body 10 so that H1 / H2≧0.05, the stress applied to the lens 30 can be further reduced.

[0059] The holding member 40 may be configured to be asymmetric with respect to the optical axis L. Such a configuration can more reliably prevent foreign matter adhering to the lens 30 from accumulating on the vibrating body 10. The asymmetry can be achieved, for example, by forming the holding member 40 from a plurality of materials, or by providing the holding member 40 with a plurality of regions having different Young's moduli, densities, or mechanical Q values.

[0060] The cross section of the arm portion 13 including the optical axis L may have any curved shape and is not limited to the above embodiment. For example, the cross section of the first arm portion 131 including the optical axis L may not have a curved shape that protrudes from the first flange portion 11 toward the second flange portion 12, and the cross section of the second arm portion 132 including the optical axis L may not have a curved shape that protrudes from the second flange portion 12 toward the first flange portion 11. The radius of curvature of the curved shape of the first arm portion 131 may not be larger than the radius of curvature of the curved shape of the second arm portion 132. The arm portion 13 may not extend along the optical axis L.

[0061] In the present disclosure, any of the various embodiments and modifications described above can be combined as appropriate. Combinations of embodiments and / or modifications include combinations of configurations included in the embodiments and / or configurations included in the examples.

[0062] The present disclosure has been fully described through the above-described embodiments and / or modifications with reference to the accompanying drawings, but the above-described embodiments and / or modifications do not encompass all of the present disclosure. Many modifications and variations are possible for those skilled in the art in the technical field of the present disclosure. Such modifications and variations should be understood to be included in the present disclosure as long as they do not depart from the scope of the present disclosure.

[0063] REFERENCE SIGNS LIST 1 vibration device 10 vibration body 11 first flange portion 12 second flange portion 13 arm portion 20 piezoelectric element 30 lens 40 holding member 41 pressing portion 50 joint portion 100 vibration device 110 vibration body 111 first flange portion 112 second flange portion 113 connecting portion 120 piezoelectric element 130 lens 131 first arm portion 132 second arm portion 133 connecting portion 140 holding member 150 joint portion 160 right angle portion 200 droplet

Claims

1. A vibrating body; a piezoelectric element located at one end of the vibrating body in a first direction; a transparent body having an optical axis extending along the first direction and positioned at the other end of the vibrator in the first direction; Equipped with The vibrating body is a first flange portion connected to the light-transmitting body; a second flange portion connected to the piezoelectric element; an arm portion connecting the first flange portion and the second flange portion; Including, the first flange portion and the second flange portion extend, in a cross section including the optical axis, from a position away from the optical axis in a second direction intersecting the first direction, along a direction approaching the optical axis in the second direction, the arm portion has a curved shape in the cross section, the cross section of the first arm portion has a curved shape that protrudes from the first flange portion toward the second flange portion, A vibration device, wherein the cross section of the second arm portion has a curved shape that protrudes from the second flange portion toward the first flange portion.

2. The arm portion a first arm portion extending from one of both ends of the first flange portion in the second direction that is farther from the optical axis toward the second flange portion; a second arm portion extending from one end of the second flange portion farther from the optical axis toward the first flange portion and connected to an end of the first arm portion opposite to the end connected to the first flange portion in the second direction; The vibration device of claim 1 , comprising:

3. When a distance in the first direction from a portion of the first flange portion that is in contact with the light-transmitting body to a connection portion of the first arm portion and the second arm portion is defined as a first distance, and a total length of the arm portion in the first direction is defined as a second distance, The vibration device of claim 2 , wherein the ratio of the first distance to the second distance is greater than or equal to 0.

05.

4. The vibration device according to any one of claims 1 to 3, further comprising a holding member positioned outside the light-transmitting body in the second direction and holding the connection between the light-transmitting body and the first flange portion.

5. The vibration device according to claim 4 , wherein the holding member is asymmetric with respect to the optical axis.

6. The vibration device according to claim 6 , wherein a radius of curvature of the curved shape of the first arm portion is larger than a radius of curvature of the curved shape of the second arm portion.

7. 4. The vibration device according to claim 1, wherein the arm portion extends along the optical axis.

8. 4. The vibration device according to claim 1, wherein the second flange portion has a thickness greater than a thickness of the first flange portion.