Vibration device and imaging device

Abstract

The present disclosure provides a vibration device and an imaging device that prevent foreign matter from collecting in a central part of a translucent body due to vibration and do not cause a decrease in vibration performance. A vibration device (10) comprises: an outermost-layer lens (1) (translucent body) that transmits light of a prescribed wavelength; a vibrating body (3) that contacts the outermost-layer lens (1) and vibrates the outermost-layer lens (1); a piezoelectric element (5) provided to the vibrating body (3); and a housing (2) that retains the outermost-layer lens (1) and covers the vibrating body (3). The vibrating body (3) includes: a first cylindrical part (31) that has a cylindrical shape and is in contact with the outermost-layer lens (1); a second cylindrical part (32) that is provided with the piezoelectric element (5); and a spring part (33) that links the first cylindrical part (31) and the second cylindrical part (32). The vibrating body (3) is such that at least one of the shape of the vibrating body (3), the physical characteristics of the material constituting the vibrating body (3), the position of the outermost-layer lens (1) in contact with the first cylindrical part, and the position of the piezoelectric element (5) provided to the second cylindrical part (32) is asymmetrical with respect to a central axis (C) of the cylindrical shape of the vibrating body (3).

Description

Vibration device and imaging device

[0001] The present disclosure relates to a vibration device and an imaging device.

[0002] In recent years, vehicles have been provided with imaging devices at the front or rear of the vehicle to control safety devices and drive assistance controls using images obtained by the imaging devices. Such imaging devices are often installed outside the vehicle, and foreign matter such as raindrops (water droplets), mud, and dust adheres to the transparent bodies (protective covers and lenses) that cover the exterior.

[0003] If foreign matter adheres to the light-transmitting body, the foreign matter will be reflected in the image captured by the imaging device, making it difficult to obtain a clear image. Therefore, in Japanese Patent Laid-Open No. 2017-170303 (Patent Document 1), an imaging device is provided with a droplet removal device (vibration device) that vibrates the light-transmitting body in order to remove foreign matter adhered to the surface of the light-transmitting body.

[0004] Japanese Patent Application Laid-Open No. 2017-170303

[0005] When a vibrating device is used to vibrate a transparent body to remove foreign matter adhering to its surface, the foreign matter gathers in the center of the transparent body, where the displacement due to vibration is greatest, and is then atomized and removed. However, if the foreign matter has a high viscosity and cannot be atomized, vibrating the transparent body with the vibrating device will cause the foreign matter to gather in the center of the transparent body, obstructing the field of view. Furthermore, if the foreign matter cannot be atomized, the mass of the vibrating transparent body will increase due to the foreign matter gathering in the center of the transparent body due to vibration, reducing the vibration performance of the vibrating device.

[0006] Therefore, an object of the present disclosure is to provide a vibration device and an imaging device that prevent foreign matter from gathering in the center of a light-transmitting body due to vibration and do not degrade vibration performance.

[0007] A vibration device according to one aspect of the present disclosure includes a translucent body that transmits light of a predetermined wavelength, a vibrator that contacts the translucent body and vibrates the translucent body, a piezoelectric element provided on the vibrator, and a housing that holds the translucent body and covers the vibrator. The vibrator is cylindrical and includes a first cylindrical portion that contacts the translucent body, a second cylindrical portion that is provided with the piezoelectric element, and a spring portion that connects the first cylindrical portion and the second cylindrical portion. The vibrator is asymmetric with respect to the central axis of the cylindrical shape of the vibrator in at least one of the following: the shape of the vibrator, the physical properties of the material that makes up the vibrator, the position of the translucent body that contacts the first cylindrical portion, and the position of the piezoelectric element provided on the second cylindrical portion.

[0008] An imaging device according to an embodiment of the present disclosure includes the vibration device described above and an imaging element arranged so that the light-transmitting body is in the field of view.

[0009] According to the present disclosure, the vibration device is asymmetrical with respect to the central axis of the cylindrical shape of the vibrating body in that at least one of the following is asymmetrical with respect to the central axis of the cylindrical shape of the vibrating body: the shape of the vibrating body, the physical properties of the material constituting the vibrating body, the position of the translucent body in contact with the first cylindrical portion, and the position of the piezoelectric element provided in the second cylindrical portion, thereby preventing foreign matter from gathering in the center of the translucent body due to vibration and not degrading vibration performance.

[0010] 1 is a cross-sectional view of an imaging device according to embodiment 1. FIG. 2 is a cross-sectional view for explaining the configuration of a vibrating body according to embodiment 1. FIG. 3 is a schematic view for explaining displacement occurring in a vibration device according to embodiment 1. FIG. 4 is a graph for explaining the relationship between a plate thickness ratio and a displacement gradient rate of a vibrating body according to embodiment 1. FIG. 5 is a schematic view for explaining the configuration of a vibrating body according to embodiment 2. FIG. 6 is a graph for explaining displacement occurring in a vibration device according to embodiment 2. FIG. 7 is a schematic view for explaining the configuration of a vibrating body according to embodiment 3. FIG. 8 is a graph for explaining displacement occurring in a vibration device according to embodiment 3. FIG. 9 is a schematic view for explaining the configuration of a vibrating body according to a modified example of embodiment 3. FIG. 10 is a graph for explaining displacement occurring in a vibration device according to a modified example of embodiment 3. FIG. 11 is a schematic view for explaining the configuration of a vibrating body according to embodiment 4. FIG. 12 is a graph for explaining displacement occurring in a vibration device according to embodiment 4. FIG. 13 is a cross-sectional view for explaining the configuration of a vibrating body according to embodiment 5. FIG. 14 is a graph for explaining displacement occurring in a vibration device according to embodiment 5. FIG. 15 is a perspective view for explaining the configuration of a vibration device according to a modified example.

[0011] The imaging device according to the present disclosure will be described in detail below with reference to the drawings. Note that the same reference numerals in the drawings indicate the same or corresponding parts. The imaging device described below is, for example, for vehicle installation, and can vibrate a transparent body (e.g., the outermost lens) to remove foreign matter adhering to the surface of the transparent body. The imaging device is not limited to vehicle installation. For example, the imaging device can also be applied to security surveillance cameras, drones, etc.

[0012] (Embodiment 1) Fig. 1 is a cross-sectional view of an imaging device 100 according to embodiment 1. Fig. 2 is a cross-sectional view for explaining the configuration of a vibrating body 3 according to embodiment 1. Note that the X, Y, and Z directions in the figure indicate the horizontal, depth, and height directions of the imaging device 100, respectively. The imaging device 100 includes a vibration device 10 and a sensor device 20. The vibration device 10 includes an outermost lens 1, a housing 2, a vibrating body 3, and a piezoelectric element 5. The sensor device 20 includes a bracket 8 that holds an imaging element 6. Although not shown, it is preferable that the imaging device 100 has an inner lens between the outermost lens 1 and the imaging element 6.

[0013] After adjusting the alignment between the outermost lens 1 and the imaging element 6, the sensor device 20 is bonded to the vibration device 10 to complete the imaging device 100. The imaging element 6 is an image sensor such as a charge-coupled device (CCD) or a complementary metal-oxide-semiconductor (CMOS) sensor, and is mounted on a circuit board 60 ( FIG. 2 ). The circuit board 60 may be mounted with semiconductor elements such as a general-purpose integrated circuit (IC) or application-specific integrated circuit (ASIC) that control the imaging element 6, as well as semiconductor elements that generate signals for driving the piezoelectric element 5. The circuit board 60 is fixed to the bracket 8 at a position where the alignment between the outermost lens 1 and the inner lens (not shown) and the imaging element 6 has been adjusted. The bracket 8 is made of, for example, aluminum (A5052).

[0014] The outermost lens 1 is a translucent body that transmits light of a predetermined wavelength (e.g., a wavelength of visible light, a wavelength that can be captured by an imaging element, etc.), and is made of, for example, borosilicate crown glass (BK7), quartz glass, crown glass, flint glass, a convex meniscus lens, etc. Note that the vibration device 10 may use a transparent member such as a protective cover instead of the outermost lens 1. The protective cover is made of glass or a resin such as transparent plastic.

[0015] An end of the outermost lens 1 is held by an end 2b of the housing 2 extending in the Z direction. The end 2b of the housing 2 contacts the outermost lens 1 with a retainer 21 sandwiched therebetween. The retainer 21 may be made of a resin such as polyphenylene sulfide (PPS) or a metal such as stainless steel (SUS304, SUS420, SUS440). The end 2b of the housing 2, the retainer 21, the outermost lens 1, and the vibrating body 3 are bonded together with, for example, an adhesive. In FIG. 1 , the housing 2 indirectly holds the outermost lens 1 via the retainer 21, but the outermost lens 1 may also be held directly by the end 2b of the housing 2.

[0016] The housing 2 includes a first portion 2 a, an end portion 2 b, a cylindrical second portion 2 c having a larger diameter than the first portion 2 a, and a third portion 2 d connecting the first portion 2 a and the second portion 2 c. The housing 2 has a shape in which two cylinders (the first portion 2 a and the second portion 2 c) with different diameters are connected by a disk (the third portion 2 d) extending in the radial direction (X and Y directions) of the first portion 2 a.

[0017] The first portion 2a is elongated in the axial direction (Z direction) of the cylinder, and the disk-shaped third portion 2d elastically deforms like a spring, allowing the cylinder to vibrate in the axial direction. A weight 2e is provided inside the second portion 2c to reduce vibration from the vibrating body 3. The first portion 2a, end portion 2b, second portion 2c, third portion 2d, and weight 2e of the housing 2 may be integrally formed or individually formed. The housing 2 may be made of, for example, stainless steel (SUS304, SUS420, SUS440), etc.

[0018] As shown in Figure 1, the vibration device 10 is in contact with a vibrating body 3 to vibrate the outermost lens 1. The vibrating body 3 is cylindrical and is composed of a first cylindrical portion 31 that is in contact with the outermost lens 1, a second cylindrical portion 32 in which a piezoelectric element 5 is provided, and a spring portion 33 that connects the first cylindrical portion 31 and the second cylindrical portion 32. The cross section of the spring portion 33 is S-shaped. An inner lens (not shown) may be placed inside the cylinder of the vibrating body 3. The vibrating body 3 is made of, for example, stainless steel (SUS304, SUS420, SUS440) or the like.

[0019] The first cylindrical portion 31 is a cylindrical portion that is elongated in the axial direction of the tube (Z direction), and its end contacts the peripheral edge of the outermost lens 1 to transmit the vibration of the vibrating body 3 to the outermost lens 1. The first cylindrical portion 31 has an end that is elongated in the radial direction of the tube (X and Y directions) to stably hold the outermost lens 1.

[0020] The second cylindrical portion 32 is a portion that vibrates together with the vibration of the piezoelectric element 5, and has a thickness greater than the thicknesses of the first cylindrical portion 31 and the spring portion 33. This makes it easier to transmit the vibration of the piezoelectric element 5 to the outermost lens 1 more efficiently.

[0021] The spring portion 33 supports the first cylindrical portion 31 and transmits vibrations of the second cylindrical portion 32 to the first cylindrical portion 31. The first cylindrical portion 31, the second cylindrical portion 32, and the spring portion 33 may be formed integrally or separately. Although the cross-sectional shape of the spring portion 33 has been described as being S-shaped, the cross-sectional shape of the spring portion 33 may be any curved shape, such as a shape that has a portion that bulges out in the radial direction of the first cylindrical portion 31 relative to the first cylindrical portion 31 (e.g., a U-shape or a shape of two S-shapes connected together). Furthermore, the spring portion 33 may have any shape as long as it can transmit vibrations of the second cylindrical portion 32 to the first cylindrical portion 31.

[0022] The piezoelectric element 5 is provided on the surface of the second cylindrical portion 32 opposite to the side in contact with the outermost lens 1. The piezoelectric element 5 is hollow and circular, and vibrates by being polarized in the thickness direction, for example. The piezoelectric element 5 is made of lead zirconate titanate piezoelectric ceramics. However, (K,Na)NbO ３ Other piezoelectric ceramics such as LiTaO may also be used. ３ A piezoelectric single crystal such as

[0023] The hollow circular piezoelectric element 5 vibrates in the radial direction, and this vibration is converted into vibration in the Z direction (up and down in the figure) by the spring portion 33 of the vibrating body 3, causing the outermost lens 1 to vibrate in the Z direction. Therefore, if the shape of the vibrating body 3 is symmetrical with respect to the central axis C of the cylindrical shape of the vibrating body 3, the vibrating device 10 vibrates the outermost lens 1 in the Z direction so that the central portion of the outermost lens 1 is displaced to the maximum. The vibrating device 10 uses vibration to move foreign matter adhering to the surface of the outermost lens 1 to the central portion of the outermost lens 1, where it is atomized and removed.

[0024] However, if the foreign matter has a high viscosity and cannot be atomized and adheres to the surface of the outermost lens 1, vibrating the outermost lens 1 with the vibration device 10 will cause the foreign matter to gather in the center of the outermost lens 1, thereby obstructing the field of view. Furthermore, if the foreign matter cannot be atomized, the mass of the outermost lens 1 that is vibrated by the foreign matter gathering in the center of the outermost lens 1 due to vibration will increase, and the vibration performance of the vibration device 10 will be reduced.

[0025] Therefore, in vibration device 10 according to the present embodiment, a displacement gradient is provided at the end of outermost lens 1 such that displacement due to vibration is greatest, preventing foreign matter from gathering in the center of outermost lens 1 and allowing any adhering foreign matter to slide off and be removed from outermost lens 1. Furthermore, in vibration device 10 according to the present embodiment, foreign matter that cannot be atomized does not gather in the center of outermost lens 1, and foreign matter is allowed to slide off and be removed from outermost lens 1, so vibration performance is not reduced.

[0026] In the vibration device 10 according to this embodiment, the shape of the vibrating body 3 is asymmetric with respect to the central axis C of the cylindrical shape of the vibrating body 3 in order to provide a displacement gradient at the end of the outermost lens 1 where displacement due to vibration is greatest. Specifically, as shown in Fig. 2, the thickness of the first cylindrical portion 31a, the second cylindrical portion 32a, and the spring portion 33a on the left side of the figure is thicker than the thickness of the first cylindrical portion 31b, the second cylindrical portion 32b, and the spring portion 33b on the right side of the figure, and the vibrating body 3 is asymmetric with respect to the central axis C. For example, when the vibrating body 3 is formed by lathe machining, the machining axis K (rotation axis) of the vibrating body 3 machined by lathe machining can be shifted from the central axis C of the vibrating body 3 to make the thickness of the vibrating body 3 asymmetric with respect to the central axis C.

[0027] By making the thickness of the vibrating body 3 asymmetrical with respect to the central axis C, the elastic modulus of the thicker first cylindrical portion 31a, the second cylindrical portion 32a, and the spring portion 33a is high, while the elastic modulus of the thinner first cylindrical portion 31b, the second cylindrical portion 32b, and the spring portion 33b is low. Therefore, the vibration device 10 exhibits a displacement gradient in which the displacement is large on the thicker first cylindrical portion 31a, the second cylindrical portion 32a, and the spring portion 33a side and small on the thinner first cylindrical portion 31b, the second cylindrical portion 32b, and the spring portion 33b side. Figure 3 is a schematic diagram illustrating displacements occurring in the vibration device 10 according to the first embodiment. Figure 3(a) is a perspective view illustrating displacements occurring in the vibration device 10, and Figure 3(b) is a cross-sectional view illustrating displacements occurring in the vibration device 10. The schematic diagram shown in Figure 3 shows the results of a simulation of the displacement that occurs in the vibration device 10 when a voltage is applied to the piezoelectric element 5 to vibrate the outermost lens 1. In Figure 3, the magnitude of the displacement is indicated by the shade of hatching, with darker hatching indicating areas with greater displacement. In the vibration device 10 shown in Figure 3, the displacement at the area with the greatest displacement is approximately 8 μm.

[0028] It can be seen from Fig. 3 that the vibration device 10 has a displacement gradient where the displacement due to vibration is greatest at the end of the outermost lens 1. Specifically, the displacement occurring in the vibration device 10 is large at the bottom of Fig. 3(a) and the left side of Fig. 3(b), and the displacement occurring in the vibration device 10 is small at the top of Fig. 3(a) and the right side of Fig. 3(b). The bottom of Fig. 3(a) and the left side of Fig. 3(b) are the sides of the thick first cylindrical portion 31a, second cylindrical portion 32a, and spring portion 33a, and the top of Fig. 3(a) and the right side of Fig. 3(b) are the sides of the thin first cylindrical portion 31b, second cylindrical portion 32b, and spring portion 33b.

[0029] In other words, the vibration device 10 causes the thicker first cylindrical portion 31a, second cylindrical portion 32a, and spring portion 33a to displace significantly, causing the outermost lens 1 to tilt and vibrate. By tilting and vibrating the outermost lens 1, it is possible to slide and remove any adhering foreign matter from the outermost lens 1. In particular, by attaching the vibration device 10 to the imaging device 100 so that the direction from the side where the displacement of the vibrating body 3 is smallest to the side where it is largest (the direction from top to bottom in FIG. 3A ) is the direction of gravity, it becomes easier to slide any adhering foreign matter off the outermost lens 1. It is more preferable that the surface of the outermost lens 1 be coated with a water-repellent or hydrophilic coating material.

[0030] As can be seen in FIG. 3B , the vibration device 10 vibrates the outermost lens 1 by elastically deforming the first and third portions 2a and 2d of the housing 2 like springs, while suppressing vibration leakage to the second portion 2c of the housing 2. The second portion 2c of the housing 2 barely displaces even when the outermost lens 1 is vibrated. Therefore, by supporting the second portion 2c of the housing 2 with a vehicle-side component, the imaging device 100 can be mounted on a vehicle without transmitting vibrations from the vibration device 10 to the vehicle. Furthermore, as shown in FIG. 2 , the wiring 51 connected to the piezoelectric element 5 is drawn from the side of the first cylindrical portion 31b, the second cylindrical portion 32b, and the spring portion 33b, which have thinner plate thicknesses, where the displacement of the vibrating body 3 is minimal, and connected to the circuit board 60. This prevents breakage of the wiring 51 and noise caused by the vibration of the wiring 51.

[0031] It has been explained that by making the thickness of the vibrating body 3 asymmetrical with respect to the central axis C, a displacement gradient can be provided in which the displacement due to vibration is greatest at the end of the outermost lens 1. Furthermore, the relationship between the thickness of the vibrating body 3 and the displacement gradient occurring in the vibration device 10 will be described in detail. Fig. 4 is a graph for explaining the relationship between the thickness ratio and the displacement gradient rate of the vibrating body 3 according to embodiment 1. In Fig. 4, the horizontal axis represents the left-right thickness ratio (the thickness ratio between the left and right sides in Fig. 2), and the vertical axis represents the displacement gradient rate of the outermost lens 1.

[0032] Here, the thickness ratio is defined as, for example, (left side thickness - right side thickness) / right side thickness in Figure 2. Therefore, as the thickness ratio increases, the asymmetry of the thickness of the vibrating body 3 with respect to the central axis C increases. Also, the displacement gradient rate is, for example, the value obtained by dividing the difference in displacement between a portion of the outermost lens 1 where the displacement is large and a portion of the outermost lens 1 where the displacement is small by the distance between the portions where the displacement is large and the portion of the outermost lens 1 where the displacement is small. Therefore, as the displacement gradient rate increases, the gradient due to the displacement of the outermost lens 1 increases.

[0033] As can be seen from the graph in Figure 4, the displacement gradient rate is maximum at approximately 0.248 µm / mm when the left / right plate thickness ratio is approximately 1.7%. In other words, it can be seen that the displacement gradient rate decreases whether the left / right plate thickness ratio is smaller or larger than approximately 1.7%. For example, the displacement gradient rate is approximately 0.155 µm / mm when the left / right plate thickness ratio is approximately 0.6%, and approximately 0.09 µm / mm when the left / right plate thickness ratio is approximately 2.9%.

[0034] As described above, in the vibration device 10 according to embodiment 1, by making the thickness of the vibrating body 3 asymmetric with respect to the central axis C, a displacement gradient is provided in which the displacement due to vibration is greatest at the end of the outermost lens 1, preventing foreign matter from concentrating in the center of the outermost lens 1 due to vibration and enabling driving without degrading vibration performance. The vibrating body 3 may be formed such that the first cylindrical portion 31, the second cylindrical portion 32, and the spring portion 33 are integrally formed or separately formed. When the first cylindrical portion 31, the second cylindrical portion 32, and the spring portion 33 are separately formed, it is sufficient that the thickness of at least one of the first cylindrical portion 31, the second cylindrical portion 32, and the spring portion 33 is asymmetric with respect to the central axis C.

[0035] (Embodiment 2) In the first embodiment, it was described that the thickness of the vibrating body 3 is asymmetric with respect to the central axis C in order to provide a displacement gradient at the end of the outermost lens 1 at which displacement due to vibration is maximized. However, the configuration for providing a displacement gradient at the end of the outermost lens 1 at which displacement due to vibration is maximized is not limited to a configuration in which the thickness of the vibrating body 3 is asymmetric with respect to the central axis C. In the vibrating body 3A according to the second embodiment, a configuration is described in which the position of the piezoelectric element 5 provided in the second cylindrical portion 32 is asymmetric with respect to the central axis C to provide a displacement gradient at the end of the outermost lens 1 at which displacement due to vibration is maximized. FIG. 5 is a schematic diagram for explaining the configuration of the vibrating body 3A according to the second embodiment. FIG. 5(a) is a side view of the vibrating body 3A, and FIG. 5(b) is a bottom view of the vibrating body 3A. Note that in the vibrating body 3A, components similar to those of the vibrating body 3 shown in FIG. 1 are designated by the same reference numerals, and their description will not be repeated. Furthermore, the vibrating body 3A can be used in place of the vibrating body 3 included in the imaging device 100 shown in FIG. 1.

[0036] The vibrating body 3A is cylindrical and is composed of a first cylindrical portion 31 that contacts the outermost lens 1, a second cylindrical portion 32 that has a piezoelectric element 5 provided therein, and a spring portion 33 that connects the first cylindrical portion 31 and the second cylindrical portion 32. The piezoelectric element 5 is provided on the surface of the second cylindrical portion 32 opposite to the side that contacts the outermost lens 1. The piezoelectric element 5 is not provided symmetrically with respect to the central axis C, but is provided displaced by an offset amount 5a with respect to the second cylindrical portion 32 as shown in FIG.

[0037] For example, when the piezoelectric element 5 of the vibrating body 3A is displaced from the second cylindrical portion 32 by an offset amount 5a of approximately 0.3 mm, the position of the piezoelectric element 5 can be made asymmetric with respect to the central axis C by approximately 5% in terms of volume. By making the position of the piezoelectric element 5 asymmetric with respect to the central axis C, the side of the vibrating body 3A where the piezoelectric element 5 is arranged closer to the central axis C (the side where the piezoelectric element 5 is smaller in terms of volume) will have stronger vibration transmission to the spring portion 33, and the side of the vibrating body 3A where the piezoelectric element 5 is arranged farther from the central axis C (the side where the piezoelectric element 5 is larger in terms of volume) will have weaker vibration transmission to the spring portion 33. Therefore, the vibrating body 3A has a displacement gradient where the displacement of the outermost lens 1 on the side where vibration transmission to the spring portion 33 is stronger is greater and the displacement of the outermost lens 1 on the side where vibration transmission to the spring portion 33 is weaker is smaller, resulting in a maximum displacement due to vibration at the end of the outermost lens 1.

[0038] Fig. 6 is a graph illustrating the displacement occurring in the vibration device according to embodiment 2. In Fig. 6, the horizontal axis represents the distance from point A shown in Fig. 5(a), and the vertical axis represents the amount of displacement of the outermost lens 1. The graph shown in Fig. 6 is a simulation result of the displacement occurring in the vibration body 3A when a voltage is applied to the piezoelectric element 5 to vibrate the outermost lens 1.

[0039] On the vibrating body 3A, the side of point A is the side where the piezoelectric element 5 is positioned closer to the central axis C, and the side away from point A is the side where the piezoelectric element 5 is positioned further away from the central axis C. Therefore, the displacement of the outermost lens 1 on the side of point A, where the vibration transmission to the spring portion 33 is strong, is large, and the displacement of the outermost lens 1 on the side away from point A, where the vibration transmission to the spring portion 33 is weak, is small. Specifically, in Figure 6, the displacement of the outermost lens 1 on the side of point A is approximately 6.2 μm, and the displacement of the outermost lens 1 on the side away from point A is approximately 4.9 μm.

[0040] As described above, in the vibration device according to the second embodiment, by making the position of the piezoelectric element 5 provided on the vibrating body 3A asymmetrical with respect to the central axis C, a displacement gradient is provided in which the displacement due to vibration is greatest at the end of the outermost lens 1, preventing foreign matter from gathering in the center of the outermost lens 1 due to vibration and enabling driving without degrading vibration performance. Furthermore, in the vibration device according to the second embodiment, by making only the position of the piezoelectric element 5 asymmetrical with respect to the central axis C, it is possible to minimize the bias of the stress applied to the vibrating body 3A. Furthermore, by making the position of the piezoelectric element 5 asymmetrical with respect to the central axis C, the symmetry of the shape of the vibrating body 3A is not impaired, ensuring the design of the vibration device. Furthermore, because the symmetry of the shape of the vibrating body 3A is not impaired, it is possible to suppress vibration leakage to the vehicle on which the imaging device is mounted.

[0041] (Embodiment 3) In the first embodiment, it was described that the thickness of the vibrating body 3 is asymmetric with respect to the central axis C in order to provide a displacement gradient at the end of the outermost lens 1 at which displacement due to vibration is maximized. However, the configuration for providing a displacement gradient at the end of the outermost lens 1 at which displacement due to vibration is maximized is not limited to a configuration in which the thickness of the vibrating body 3 is asymmetric with respect to the central axis C. In the vibration device according to the third embodiment, a configuration is described in which the shape of the vibrating body 3B is asymmetric with respect to the central axis C to provide a displacement gradient at the end of the outermost lens 1 at which displacement due to vibration is maximized. FIG. 7 is a schematic diagram for explaining the configuration of the vibrating body 3B according to the third embodiment. FIG. 7(a) is a cross-sectional view of the vibrating body 3B, and FIG. 7(b) is a perspective view of the vibrating body 3B. Note that in the vibrating body 3B, components similar to those of the vibrating body 3 shown in FIG. 1 are denoted by the same reference numerals, and their description will not be repeated. Furthermore, the vibrating body 3B can be used in place of the vibrating body 3 included in the imaging device 100 shown in FIG. 1.

[0042] The vibrating body 3B is cylindrical and is composed of a first cylindrical portion 31 that contacts the outermost lens 1, a second cylindrical portion 32 that has the piezoelectric element 5 provided therein, and a spring portion 33 that connects the first cylindrical portion 31 and the second cylindrical portion 32. As shown in FIG. 7A, the spring portion 33 has an additional member 33c that makes the plate thickness asymmetric with respect to the central axis C. The additional member 33c may be made of the same material as the spring portion 33 or a different material. Furthermore, the additional member 33c may be formed integrally with the spring portion 33 or may be formed separately from the spring portion 33.

[0043] The additional member 33c has a thickness of, for example, about 0.2 mm, and the thickness of the side where the additional member 33c is provided is about 2.8% thicker than the thickness of the side where the additional member 33c is not provided. Therefore, the additional member 33c allows the thickness of the spring portion 33 of the vibrating body 3B to be asymmetric with respect to the central axis C. By making the thickness of the spring portion 33 asymmetric with respect to the central axis C, a difference in the elastic modulus of the vibrating body 3B occurs between the thick side of the spring portion 33 and the thin side of the spring portion 33, and it is possible to provide a displacement gradient at the end of the outermost lens 1 where displacement due to vibration is greatest.

[0044] Fig. 8 is a graph illustrating the displacement occurring in the vibration device according to embodiment 3. In Fig. 8, the horizontal axis represents the distance from point A shown in Fig. 7(a), and the vertical axis represents the amount of displacement of the outermost lens 1. The graph shown in Fig. 8 is a simulation result of the displacement occurring in the vibration body 3B when a voltage is applied to the piezoelectric element 5 to vibrate the outermost lens 1.

[0045] In vibrating body 3B, spring portion 33 is thinner on the side of point A and thicker on the side away from point A. As a result, the elastic modulus is lower on the thinner side of spring portion 33, resulting in smaller displacement of outermost lens 1 on the side of point A, and the elastic modulus is higher on the thicker side of spring portion 33, resulting in larger displacement of outermost lens 1 on the side away from point A. Specifically, in Figure 8, the displacement of outermost lens 1 on the side of point A is approximately 4.3 μm, and the displacement of outermost lens 1 on the side away from point A is approximately 6.4 μm.

[0046] (Modification) In the vibration body 3B, a configuration in which an additional member 33c is provided on the spring portion 33 to make the shape of the vibration body 3B asymmetric with respect to the central axis C has been described. However, the configuration in which the shape of the vibration body 3B is asymmetric with respect to the central axis C is not limited to the configuration in which an additional member 33c is provided. In a vibration device according to a modification, a configuration in which grooves or holes are provided on the spring portion 33 of the vibration body 3C to make the shape of the vibration body 3C asymmetric with respect to the central axis C and to provide a displacement gradient at the end of the outermost lens 1 in which displacement due to vibration is maximized will be described. FIG. 9 is a schematic diagram illustrating the configuration of the vibration body 3C according to a modification of the third embodiment. FIG. 9(a) is a cross-sectional view of the vibration body 3C, and FIG. 9(b) is a perspective view of the vibration body 3C. Note that in the vibration body 3C, components similar to those of the vibration body 3 shown in FIG. 1 are designated by the same reference numerals, and their description will not be repeated. Furthermore, the vibration body 3C can be used in place of the vibration body 3 included in the imaging device 100 shown in FIG. 1.

[0047] The vibrating body 3C is cylindrical and is composed of a first cylindrical portion 31 that contacts the outermost lens 1, a second cylindrical portion 32 that has the piezoelectric element 5 provided therein, and a spring portion 33 that connects the first cylindrical portion 31 and the second cylindrical portion 32. As shown in FIG. 9( a), the spring portion 33 has a hole 33d formed therein to make the shape of the vibrating body 3C asymmetric with respect to the central axis C. The hole 33d penetrates the spring portion 33 at a position approximately 7 mm away from the central axis C. Instead of the hole 33d, a groove (a recess that does not penetrate the spring portion 33) may be formed in the spring portion 33 at a position approximately 7 mm away from the central axis C.

[0048] The holes 33d have a diameter of, for example, approximately 0.5 mm, and two of them are provided in the spring portion 33. Therefore, the holes 33d allow the shape of the spring portion 33 of the vibrating body 3C to be asymmetric with respect to the central axis C. By making the shape of the spring portion 33 asymmetric with respect to the central axis C, a difference in the elastic modulus of the vibrating body 3C occurs between the side of the spring portion 33 where the holes 33d are provided and the side of the spring portion 33 where the holes 33d are not provided, and it is possible to provide a displacement gradient at the end of the outermost lens 1 where displacement due to vibration is greatest.

[0049] Fig. 10 is a graph illustrating the displacement occurring in a vibration device according to a modified example of embodiment 3. In Fig. 10, the horizontal axis represents the distance from point A shown in Fig. 9(a), and the vertical axis represents the amount of displacement of outermost lens 1. The graph shown in Fig. 10 is a simulation result of the displacement occurring in vibration body 3C when a voltage is applied to piezoelectric element 5 to vibrate outermost lens 1.

[0050] In vibrating body 3C, the elastic modulus is lowered by providing hole 33d in spring portion 33 on the side away from point A, and the elastic modulus of spring portion 33 on the side of point A is higher. As a result, the displacement of outermost lens 1 on the side of point A where hole 33d is not provided in spring portion 33 is large, and the displacement of outermost lens 1 on the side away from point A where hole 33d is provided in spring portion 33 is small. Specifically, in Figure 10, the displacement of outermost lens 1 on the side of point A is approximately 6.4 μm, and the displacement of outermost lens 1 on the side away from point A is approximately 4.6 μm.

[0051] As described above, in the vibration device according to embodiment 3, by making the shapes of the vibrating bodies 3B and 3C asymmetrical with respect to the central axis C, a displacement gradient is provided in which the displacement due to vibration is greatest at the end of the outermost lens 1, preventing foreign matter from gathering in the center of the outermost lens 1 due to vibration and enabling driving without degrading vibration performance. Also, in the vibration device according to embodiment 3, by making the shapes of the vibrating bodies 3B and 3C asymmetrical with respect to the central axis C, the symmetry of the shape of the housing 2 that covers the vibrating bodies 3B and 3C is not compromised, ensuring the design of the vibration device. Furthermore, because the symmetry of the shape of the housing 2 is not compromised, vibration leakage to the vehicle on which the imaging device is mounted can be suppressed.

[0052] In the vibration device of embodiment 3, it has been explained that additional members 33c and holes 33d are provided in the spring portion 33 in order to make the shapes of the vibrating bodies 3B and 3C asymmetric with respect to the central axis C, but it is sufficient to provide additional members and holes in at least one of the first cylindrical portion 31, the second cylindrical portion 32, and the spring portion 33.

[0053] (Embodiment 4) The configuration of providing a displacement gradient at the end of the outermost lens 1 where the displacement due to vibration is greatest is not limited to the configuration described in embodiment 1 where the plate thickness of the vibrating body 3 is asymmetric with respect to the central axis C. In a vibration device according to embodiment 4, a configuration is described in which a displacement gradient is provided at the end of the outermost lens 1 where the displacement due to vibration is greatest by making the physical properties of the material constituting the vibrating body 3D asymmetric with respect to the central axis C. FIG. 11 is a schematic diagram for explaining the configuration of the vibrating body 3D according to embodiment 4. FIG. 11(a) is a cross-sectional view of the vibrating body 3D, and FIG. 11(b) is a perspective view of the vibrating body 3D. Note that in the vibrating body 3D, components similar to those of the vibrating body 3 shown in FIG. 1 are designated by the same reference numerals, and their description will not be repeated. Furthermore, the vibrating body 3D can be used in place of the vibrating body 3 included in the imaging device 100 shown in FIG. 1.

[0054] The vibrating body 3D is cylindrical and includes a first cylindrical portion in contact with the outermost lens 1, a second cylindrical portion in which the piezoelectric element 5 is provided, and a spring portion connecting the first and second cylindrical portions. The first cylindrical portion includes a first cylindrical portion 31f made of a material with a high elastic modulus and a first cylindrical portion 31e made of a material with a low elastic modulus. The second cylindrical portion includes a second cylindrical portion 32f made of a material with a high elastic modulus and a second cylindrical portion 32e made of a material with a low elastic modulus. The spring portion includes a spring portion 33f made of a material with a high elastic modulus and a spring portion 33e made of a material with a low elastic modulus. As shown in FIG. 11( a), the vibrating body 3D is configured with a material with a high elastic modulus on the left side and a material with a low elastic modulus on the right side relative to the central axis C. Note that the vibrating body 3D is configured by bonding different materials with different elastic moduli by welding or the like.

[0055] For example, SUS420J2 is used as a material with a high elastic modulus, and SUS303 or SUS304 is used as a material with a low elastic modulus. By making the elastic moduli of the materials constituting the vibrating body 3D asymmetric with respect to the central axis C, a difference in elastic modulus occurs between the different materials, and it is possible to provide a displacement gradient in which the displacement due to vibration is greatest at the end of the outermost lens 1. Note that, in the vibrating body 3D, elastic modulus has been described as an example of a physical property of the material that is asymmetric with respect to the central axis C, but this is not limited to this and other physical properties such as hardness and density may also be used.

[0056] Fig. 12 is a graph illustrating the displacement occurring in the vibration device according to embodiment 4. In Fig. 12, the horizontal axis represents the distance from point A shown in Fig. 11(a), and the vertical axis represents the amount of displacement of the outermost lens 1. The graph shown in Fig. 11 is a simulation result of the displacement occurring in the vibration body 3D when a voltage is applied to the piezoelectric element 5 to vibrate the outermost lens 1.

[0057] For vibration body 3D, a material with a high elastic modulus is used on the side of point A, and a material with a low elastic modulus is used on the side away from point A. As a result, the displacement of outermost lens 1 on the side of point A with a high elastic modulus is large, and the displacement of outermost lens 1 on the side away from point A with a low elastic modulus is small. Specifically, in Figure 12, the displacement of outermost lens 1 on the side of point A is approximately 6.5 μm, and the displacement of outermost lens 1 on the side away from point A is approximately 4.7 μm.

[0058] As described above, in the vibration device according to embodiment 4, by making the physical properties of the material of the vibrating body 3D asymmetric with respect to the central axis C, a displacement gradient is provided in which the displacement due to vibration is greatest at the end of the outermost lens 1, preventing foreign matter from gathering in the center of the outermost lens 1 due to vibration and enabling driving without degrading vibration performance. Also, in the vibration device according to embodiment 4, by making the physical properties of the material of the vibrating body 3D asymmetric with respect to the central axis C, the symmetry of the shape of the housing 2 that covers the vibrating body 3D is not impaired, ensuring the design of the vibration device. Furthermore, because the symmetry of the shape of the housing 2 is not impaired, vibration leakage to the vehicle on which the imaging device is mounted can be suppressed.

[0059] (Embodiment 5) In embodiment 2, a configuration was described in which the position of the piezoelectric element 5 provided in the second cylindrical portion 32 is asymmetrical with respect to the central axis C, thereby providing a displacement gradient in which the displacement due to vibration is maximized at the end of the outermost lens 1. However, the configuration in which the displacement gradient in which the displacement due to vibration is maximized at the end of the outermost lens 1 is provided is not limited to a configuration in which the position of the piezoelectric element 5 is asymmetrical with respect to the central axis C. In embodiment 5, a vibrating body 3E is described in which the position of the outermost lens 1 in contact with the first cylindrical portion 31 is asymmetrical with respect to the central axis C, thereby providing a displacement gradient in which the displacement due to vibration is maximized at the end of the outermost lens 1. Figure 13 is a cross-sectional view for explaining the configuration of the vibrating body 3E according to embodiment 5. Note that in the vibrating body 3E, components similar to those of the vibrating body 3 shown in Figure 1 are denoted by the same reference numerals, and their description will not be repeated. Furthermore, the vibrating body 3E can be used in place of the vibrating body 3 included in the imaging device 100 shown in Figure 1.

[0060] The vibrating body 3E is cylindrical and is composed of a first cylindrical portion 31 that contacts the outermost lens 1, a second cylindrical portion 32 that has a piezoelectric element 5 provided therein, and a spring portion 33 that connects the first cylindrical portion 31 and the second cylindrical portion 32. The outermost lens 1 is not provided symmetrically with respect to the central axis C, and contacts the first cylindrical portion 31 with the lens center L shifted from the central axis C by an offset amount 1a as shown in FIG.

[0061] The first cylindrical portion 31 and the outermost lens 1 of the vibrating body 3E are in contact with each other with the central axis C shifted by an offset amount 1a of approximately 0.2 mm in the positive X direction, for example, with respect to the lens center L. By making the position of the outermost lens 1 in contact with the first cylindrical portion 31 asymmetrical with respect to the central axis C, the specific gravity of the outermost lens 1 acting on the vibrating body 3E on the side of the lens center L with respect to the central axis C is smaller than the specific gravity of the outermost lens 1 acting on the vibrating body 3E on the side of the lens center L with respect to the central axis C. Therefore, the vibrating body 3E can be provided with a displacement gradient in which the displacement of the outermost lens 1 on the side with the smaller specific gravity of the outermost lens 1 is greater and the displacement of the outermost lens 1 on the side with the larger specific gravity of the outermost lens 1 is smaller, and the displacement due to vibration is greatest at the end of the outermost lens 1.

[0062] Fig. 14 is a graph illustrating the displacement occurring in the vibration device according to embodiment 5. In Fig. 14, the horizontal axis represents the distance from point A shown in Fig. 13, and the vertical axis represents the amount of displacement of the outermost lens 1. The graph shown in Fig. 13 is a simulation result of the displacement occurring in the vibration body 3E when a voltage is applied to the piezoelectric element 5 to vibrate the outermost lens 1.

[0063] With respect to vibrating body 3E, the side of point A is the side where the specific gravity of outermost lens 1 is greater, and the side away from point A is the side where the specific gravity of outermost lens 1 is less. Therefore, the displacement of outermost lens 1 on the side of point A where the specific gravity of outermost lens 1 is greater is smaller, and the displacement of outermost lens 1 on the side away from point A where the specific gravity of outermost lens 1 is less is larger. Specifically, in Figure 14, the displacement of outermost lens 1 on the side of point A is approximately 5.2 μm, and the displacement of outermost lens 1 on the side away from point A is approximately 5.9 μm.

[0064] As described above, in the vibration device according to embodiment 5, by making the position of the outermost lens 1 in contact with the first cylindrical portion 31 of the vibrating body 3E asymmetrical with respect to the central axis C, a displacement gradient is provided that minimizes vibration-induced displacement at the end of the outermost lens 1, preventing foreign matter from gathering in the center of the outermost lens 1 due to vibration and enabling driving without degrading vibration performance. Furthermore, in the vibration device according to embodiment 5, by making only the position of the outermost lens 1 asymmetrical with respect to the central axis C, it is possible to minimize the bias of stress applied to the vibrating body 3E. Furthermore, by making the position of the outermost lens 1 asymmetrical with respect to the central axis C, the symmetry of the shape of the vibrating body 3E is not compromised, ensuring the design of the vibration device. Furthermore, because the symmetry of the shape of the vibrating body 3E is not compromised, it is possible to suppress vibration leakage to the vehicle on which the imaging device is mounted.

[0065] (Other Modified Examples) As shown in FIG. 1 , the vibration device 10 employs a vibrating body 3 in which the cross-sectional shape of the spring portion 33 is S-shaped. However, the structure of the vibrating body 3 is not limited to a structure in which the cross-sectional shape of the spring portion 33 is S-shaped. FIG. 15 is a perspective view for explaining the configuration of a vibration device 10A according to a modified example. Note that in the vibration device 10A, components similar to those of the vibration device 10 shown in FIG. 1 are given the same reference numerals, and their description will not be repeated. Furthermore, components of the vibration device 10A not shown in FIG. 15 are the same as those of the vibration device 10 shown in FIG. 1.

[0066] As shown in Fig. 15, the vibrating body 3F has a cylindrical shape. The vibrating body 3F is composed of a first cylindrical portion 31 that contacts the outermost lens 1, a second cylindrical portion 32 that has the piezoelectric element 5 provided therein, and a spring portion 33g that connects the first cylindrical portion 31 and the second cylindrical portion 32. The first cylindrical portion 31, the second cylindrical portion 32, and the spring portion 33g may be formed integrally or separately.

[0067] The spring portion 33g is a side portion of the vibrating body 3F, and multiple grooves 30 each shaped like a horizontal Y (tuning fork) are formed in the spring portion 33g at equal intervals in the circumferential direction of the vibrating body 3F. The grooves 30 penetrate the spring portion 33g and are openings that penetrate the vibrating body 3F in the radial direction.

[0068] The groove 30 has a horizontal Y-shape (tuning fork shape) and is symmetrical about the radial direction of the vibrating body 3F. The groove 30 is formed so that one end contacts the first cylindrical portion 31 and the other end contacts the second cylindrical portion 32. The portion of the spring portion 33g that remains after the groove 30 is provided becomes a plurality of U-shaped pillars 35 that connect the first cylindrical portion 31 and the second cylindrical portion 32. The pillars 35 function as springs that vibrate the outermost lens 1 in the Z direction.

[0069] Pillar 35 has a horizontal U-shape. As shown in Fig. 7 , pillar 35 has a shape in which the connection portion with first cylindrical portion 31 and the connection portion with second cylindrical portion 32 are arranged on a substantially straight line. Therefore, vibration of piezoelectric element 5 causes vibrator 3F to narrow or widen the U-shaped portion of pillar 35, thereby vibrating outermost lens 1 in the Z direction.

[0070] Furthermore, as described in the above-mentioned embodiments 1 to 4, the vibration device 10A can achieve the same effect by making at least one of the following asymmetric with respect to the central axis of the cylindrical shape of the vibration body 3F: the shape of the vibration body 3F, the physical properties of the material constituting the vibration body 3F, the position of the outermost lens 1 in contact with the first cylindrical portion 31, and the position of the piezoelectric element 5 provided in the second cylindrical portion 32.

[0071] Furthermore, the configurations described in the vibration device according to the above embodiment and the vibration device according to the above modification can be combined as appropriate. Furthermore, the imaging device according to the above embodiment may include a camera, LiDAR, radar, etc. Furthermore, multiple imaging devices may be arranged side by side.

[0072] The imaging device according to the above-described embodiment is not limited to an imaging device installed in a vehicle, but can be similarly applied to any imaging device that includes an optical device and an imaging element arranged so that a light-transmitting body is in the field of view, and that requires removal of foreign matter from the light-transmitting body.

[0073] (Aspects) (1) A vibration device according to the present disclosure includes a translucent body that transmits light of a predetermined wavelength; a vibrating body that contacts the translucent body and vibrates the translucent body; a piezoelectric element provided on the vibrating body; and a housing that holds the translucent body and covers the vibrating body, wherein the vibrating body is cylindrical and includes a first cylindrical portion that contacts the translucent body, a second cylindrical portion that provides the piezoelectric element, and a spring portion that connects the first cylindrical portion and the second cylindrical portion, and at least one of the shape of the vibrating body, the physical properties of the material that makes up the vibrating body, the position of the translucent body that contacts the first cylindrical portion, and the position of the piezoelectric element provided on the second cylindrical portion is asymmetric with respect to the central axis of the cylindrical shape of the vibrating body.

[0074] As a result, in the vibration device of the present disclosure, at least one of the following is asymmetric with respect to the central axis of the cylindrical shape of the vibrating body: the shape of the vibrating body, the physical properties of the material constituting the vibrating body, the position of the translucent body in contact with the first cylindrical portion, and the position of the piezoelectric element provided in the second cylindrical portion, thereby preventing foreign matter from gathering in the center of the translucent body due to vibration and not degrading vibration performance.

[0075] (2) In the vibrating device described in (1), the vibrating body has a thickness of at least one of the first cylindrical portion, the second cylindrical portion, and the spring portion that is asymmetric with respect to the central axis.

[0076] (3) In the vibrating device described in (2), the machining axis of the vibrating body machined by lathe machining is shifted from the central axis, and the plate thickness of the vibrating body is asymmetric with respect to the central axis.

[0077] (4) In the vibration device described in any one of (1) to (3), the vibrating body has grooves or holes asymmetrically provided with respect to the central axis in at least one of the first cylindrical portion, the second cylindrical portion, and the spring portion.

[0078] (5) In the vibration device described in any one of (1) to (4), the vibrating body is configured such that at least one of the first cylindrical portion, the second cylindrical portion, and the spring portion is made of materials with different elastic moduli, which are asymmetrically arranged with respect to the central axis.

[0079] (6) In the vibration device according to any one of (1) to (5), the spring portion has an S-shaped cross section.

[0080] (7) In the vibration device described in any one of (1) to (6), the spring portion has a shape that has a portion that bulges out in the radial direction of the first cylindrical portion relative to the first cylindrical portion.

[0081] (8) In the vibration device according to any one of (1) to (5), the spring portion has a shape having a plurality of grooves arranged in the circumferential direction of the vibrating body.

[0082] (9) In the vibration device described in any one of (1) to (8), the second cylindrical portion has a portion whose shape is extended in the radial direction of the second cylindrical portion, and a piezoelectric element is provided in that portion.

[0083] (10) In the vibrating device according to any one of (1) to (9), the wiring connected to the piezoelectric element is drawn out from the side where the displacement of the vibrating body is smallest.

[0084] (11) An imaging device according to the present disclosure includes the vibration device according to any one of (1) to (10) above, and an imaging element arranged such that the light-transmitting body is in the field of view.

[0085] (12) In the imaging element according to (11), the vibration device is attached to the imaging device so that the direction from the side where the displacement of the vibration body is minimum to the side where the displacement is maximum is the direction of gravity.

[0086] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0087] 1 Outermost lens, 2 Housing, 2a First portion, 2b End portion, 2c Second portion, 2d Third portion, 2e Weight, 3, 3A to 3F Vibrating body, 5 Piezoelectric element, 6 Imaging element, 8 Bracket, 10, 10A Vibration device, 20 Sensor device, 21 Retainer, 30 Groove portion, 31, 31a, 31b, 31e, 31f First cylindrical portion, 32, 32a, 32b, 32e, 32f Second cylindrical portion, 33, 33a, 33b, 33e, 33f, 33g Spring portion, 33c Additional member, 33d Hole, 35 Pillar, 51 Wiring, 60 Circuit board, 100 Imaging device.

Claims

1. A vibration device comprising: a translucent body that transmits light of a predetermined wavelength; a vibrating body that contacts the translucent body and vibrates the translucent body; a piezoelectric element provided on the vibrating body; and a housing that holds the translucent body and covers the vibrating body, wherein the vibrating body is cylindrical and includes a first cylindrical portion that contacts the translucent body, a second cylindrical portion that provides the piezoelectric element, and a spring portion that connects the first cylindrical portion and the second cylindrical portion, and wherein at least one of the shape of the vibrating body, the physical properties of the material that makes up the vibrating body, the position of the translucent body that contacts the first cylindrical portion, and the position of the piezoelectric element provided on the second cylindrical portion is asymmetric with respect to the central axis of the cylindrical shape of the vibrating body.

2. The vibration device according to claim 1, wherein the thickness of at least one of the first cylindrical portion, the second cylindrical portion, and the spring portion of the vibrating body is asymmetric with respect to the central axis.

3. The vibration device according to claim 2, wherein the machining axis of the vibrating body machined by lathe machining is shifted from the central axis, and the plate thickness of the vibrating body is asymmetric with respect to the central axis.

4. A vibration device according to any one of claims 1 to 3, wherein the vibrating body has grooves or holes asymmetrically provided in at least one of the first cylindrical portion, the second cylindrical portion, and the spring portion with respect to the central axis.

5. A vibration device as described in any one of claims 1 to 4, wherein at least one of the first cylindrical portion, the second cylindrical portion, and the spring portion of the vibrating body is configured using materials with different elastic moduli that are asymmetrically arranged with respect to the central axis.

6. A vibration device according to any one of claims 1 to 5, wherein the cross section of the spring portion is S-shaped.

7. A vibration device according to any one of claims 1 to 6, wherein the spring portion has a shape that has a portion that bulges out in the radial direction of the first cylindrical portion relative to the first cylindrical portion.

8. A vibration device according to any one of claims 1 to 5, wherein the spring portion has a shape having a plurality of grooves arranged in the circumferential direction of the vibrating body.

9. A vibration device as described in any one of claims 1 to 8, wherein the second cylindrical portion has a portion whose shape is extended in the radial direction of the second cylindrical portion, and the piezoelectric element is provided in this portion.

10. A vibration device according to any one of claims 1 to 9, wherein the wiring connected to the piezoelectric element is drawn out from the side of the vibrating body where the displacement is smallest.

11. An imaging device comprising: the vibration device according to any one of claims 1 to 10; and an imaging element arranged so that the light-transmitting body is in the field of view.

12. The imaging device according to claim 11, wherein the vibration device is attached to the imaging device so that the direction from the side where the displacement of the vibrating body is minimum to the side where the displacement is maximum coincides with the direction of gravity.

Images