Vibration device and imaging device

Abstract

The present disclosure provides: a vibration device that, by means of vibration, prevents foreign matter from gathering at the center of a translucent body and keeps a field of view unobstructed; and an imaging device. A vibration device (10) comprises: a translucent body (outermost layer lens (1)) that transmits light having a prescribed wavelength; a vibrating body (3) that is in contact with the translucent body and causes the translucent body to vibrate; and a vibration source (piezoelectric element (5)) provided to the vibrating body (3). Vibration source-based vibrational components of the translucent body include at least: a first component in the optical axis direction of light passing through the translucent body from the vibrating body side; and a second component in a direction orthogonal to the optical axis direction.

Description

Vibration device and imaging device

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

[0002] In recent years, in vehicles, imaging devices are provided at the front and rear of the vehicle in order to control safety devices or perform driving support control using images obtained by the imaging devices. Such imaging devices are often provided outside the vehicle, and foreign substances such as raindrops (water droplets), mud, and dust adhere to the light-transmitting body (protective cover or lens) that covers the outside.

[0003] When foreign substances adhere to the light-transmitting body, the foreign substances are reflected in the image obtained by the imaging device, and a clear image cannot be obtained. Therefore, in Japanese Patent Application Laid-Open No. 2017-170303 (Patent Document 1), an imaging device is provided with a droplet elimination device (vibration device) that vibrates the light-transmitting body in order to remove foreign substances adhering to the surface of the light-transmitting body.

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

[0005] When the light-transmitting body is vibrated by the vibration device to remove foreign substances adhering to the surface of the light-transmitting body, the foreign substances are collected at the central portion of the light-transmitting body where the displacement due to vibration is maximum, and the foreign substances are atomized and removed. However, when foreign substances with high viscosity that cannot be atomized adhere to the surface of the light-transmitting body, the foreign substances gather at the central portion of the light-transmitting body by vibrating the light-transmitting body with the vibration device, obstructing the field of view.

[0006] Therefore, an object of the present disclosure is to provide a vibration device and an imaging device that prevent foreign substances from gathering at the central portion of the light-transmitting body due to vibration and do not obstruct the field of view.

[0007] A vibration device according to an aspect of the present disclosure includes a light-transmitting body that transmits light of a predetermined wavelength, a vibrating body that contacts the light-transmitting body and vibrates the light-transmitting body, and a vibration source provided on the vibrating body. The vibration component of the light-transmitting body based on the vibration source includes at least a first component in the optical axis direction of the light that passes through the light-transmitting body from the side of the vibrating body and a second component in a direction orthogonal to the optical axis direction.

[0008] An imaging device according to an aspect of the present disclosure includes the above-described vibration device and an imaging element arranged such that the light-transmitting body faces the field of view direction.

[0009] According to this disclosure, the vibration device, based on the vibration source, includes at least a first component in the direction of the optical axis of light passing through the transparent material from the side of the vibrating material, and a second component in a direction perpendicular to the optical axis. Therefore, vibration prevents foreign matter from accumulating in the central part of the transparent material and does not obstruct the field of view.

[0010] This is a cross-sectional view of the imaging device according to Embodiment 1. This is a schematic diagram illustrating the force acting on foreign matter attached to the surface of the outermost lens. This is a schematic diagram illustrating the relationship between the vibration component in the Z direction of the outermost lens and the force acting on the foreign matter. This is a schematic diagram illustrating the relationship between the vibration component of the outermost lens and the force acting on the foreign matter in the vibration device according to Embodiment 1. This is a perspective view of the vibration device according to Embodiment 2. This is a schematic diagram illustrating the displacement occurring in the vibration device according to Embodiment 2. This is a graph illustrating the relationship between the ratio of vibration components and the coupling coefficient. This is a cross-sectional view of the imaging device according to Embodiment 3. This is a schematic diagram illustrating the displacement occurring in the vibration device according to Embodiment 3.

[0011] The imaging device described below will be described in detail with reference to the drawings. In the drawings, the same reference numerals indicate the same or corresponding parts. The imaging device described below is, for example, for automotive use and includes a vibrator and a vibration source that vibrate a transparent material (e.g., the outermost lens) to remove foreign matter adhering to the surface of the transparent material. The imaging device is not limited to automotive applications. For example, the imaging device can also be applied to security cameras, drones, etc.

[0012] (Embodiment 1) Figure 1 is a cross-sectional view of the imaging device 100 according to Embodiment 1. In the figure, the X, Y, and Z directions indicate the lateral, depth, and height directions of the imaging device 100, respectively. The imaging device 100 includes a vibrator 10 and a sensor device 20. The vibrator 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 the image sensor 6. Although not shown, it is preferable to provide an inner lens between the outermost lens 1 and the image sensor 6 in the imaging device 100.

[0013] After adjusting the alignment between the outermost lens 1 and the image sensor 6, the sensor device 20 is joined to the vibration device 10 to form the imaging device 100. The image sensor 6 is an image sensor such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal-Oxide-Semiconductor) sensor, and is mounted on a circuit board (not shown). The circuit board not only has semiconductor elements such as general-purpose ICs (Integrated Circuits) and ASICs (Application Specific Integrated Circuits) mounted on it to control the image sensor 6, but may also have semiconductor elements that generate signals to drive the piezoelectric element 5. The circuit board (not shown) is fixed to the bracket 8 in a position where the alignment between the outermost lens 1 and the inner lens (not shown) and the image sensor 6 has been adjusted. The bracket 8 is made of aluminum (A5052), for example.

[0014] The outermost lens 1 is a light-transmitting material that transmits light of a predetermined wavelength (for example, the wavelength of visible light, the wavelength that can be imaged by the image sensor, etc.), and is, for example, borosilicate crown glass (BK7), quartz glass, crown glass, flint glass, or a convex meniscus lens. 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 a transparent plastic or other resin or glass.

[0015] The end of the outermost lens 1 is held by the end 2b of the housing 2, which extends in the Z direction. The end 2b of the housing 2 is in contact with the outermost lens 1, with a retainer 21 in between. 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 vibrator 3 are bonded together, for example, with an adhesive. In Figure 1, the housing 2 indirectly holds the outermost lens 1 via the retainer 21, but it may also be held directly by the end 2b of the housing 2.

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

[0017] The first portion 2a is shaped to extend in the axial direction (Z direction) of the cylinder, and the disc-shaped third portion 2d can vibrate in the axial direction (Z direction) of the cylinder and in directions perpendicular to the axial direction (X, Y directions) by elastically deforming like a spring. In addition, a weight 2e is provided inside the second portion 2c to reduce vibration from the vibrating body 3. Furthermore, the housing 2, first portion 2a, end portion 2b, second portion 2c, third portion 2d, and weight 2e may be formed as a single unit or individually. The housing 2 can be made of, for example, stainless steel (SUS304, SUS420, SUS440).

[0018] As shown in Figure 1, the vibrating device 10 is in contact with the vibrating body 3 in order to vibrate the outermost lens 1. The vibrating body 3 is cylindrical in shape and consists of a first cylindrical portion 31 that is in contact with the outermost lens 1, a second cylindrical portion 32 on which the 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-sectional shape of the spring portion 33 is S-shaped. An inner lens may be placed inside the cylinder of the vibrating body 3, although this is not shown. The vibrating body 3 is made of, for example, stainless steel (SUS304, SUS420, SUS440).

[0019] The first cylindrical portion 31 is a cylindrical part whose shape is extended in the axial direction (Z direction) of the cylinder, and its end contacts the peripheral edge of the outermost lens 1, transmitting the vibrations of the vibrator 3 to the outermost lens 1. The first cylindrical portion 31 has an end that is extended in the radial direction (X, Y direction) of the cylinder in order to stably hold the outermost lens 1.

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

[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 as a single unit or individually. Furthermore, although the cross-sectional shape of the spring portion 33 has been described as S-shaped, the spring portion 33 may have any shape that bulges radially outward from the first cylindrical portion 31 (for example, a U-shape or a shape with two S-shapes connected). Moreover, the spring portion 33 may have any shape that can transmit vibrations of the second cylindrical portion 32 to the first cylindrical portion 31.

[0022] The piezoelectric element 5 is a vibration source and 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, for example, by polarization in the thickness direction. The piezoelectric element 5 is made of lead zirconate titanate piezoelectric ceramics. ３ Other piezoelectric ceramics such as LiTaO may also be used. ３ Piezoelectric single crystals such as the above may be used. Although the piezoelectric element 5 was described as an example of a vibration source for vibrating the vibrating body 3, the vibration source may also be an electromagnetic vibration source, a magnetostrictive vibration source, an actuator vibration source, or an SMA (Shape Memory Alloy) vibration source.

[0023] Here, we will explain the forces acting on foreign matter attached to the surface of the outermost lens 1. Figure 2 is a schematic diagram illustrating the forces acting on foreign matter 70 attached to the surface of the outermost lens 1. First, the vibration device 10 vibrates the hollow circular piezoelectric element 5 radially, and this vibration is converted into vibration in the Z direction (up and down direction in the figure) by the spring portion 33 of the vibrating body 3, causing the outermost lens 1 to vibrate in the Z direction (vibration B). By vibrating the outermost lens 1 in the Z direction (vibration B), a force Fc acts on the foreign matter 70 attached to the surface of the outermost lens 1 toward the center of the outermost lens 1. On the other hand, a force Fg also acts on the foreign matter 70 in the direction of sliding off the surface of the outermost lens 1.

[0024] Therefore, if the force Fc directed toward the center of the outermost lens 1 is greater than the force Fg in the direction of sliding down from the surface of the outermost lens 1 (Fc > Fg), the foreign matter 70 adhering to the surface of the outermost lens 1 will accumulate in the center of the outermost lens 1 due to vibration. However, if the foreign matter 70 adhering to the surface of the outermost lens 1 is highly viscous and cannot be atomized, the accumulation of the foreign matter 70 in the center of the outermost lens 1 will obstruct the field of view.

[0025] Therefore, in order to prevent foreign matter 70 from accumulating in the center of the outermost lens 1, it is preferable that the force Fc directed toward the center of the outermost lens 1 be smaller than the force Fg in the direction of sliding down from the surface of the outermost lens 1 (Fc < Fg). To achieve this relationship, it would be desirable to make the force Fg in the direction of sliding down from the surface of the outermost lens 1 sufficiently large relative to the force Fc directed toward the center of the outermost lens 1, but this may be difficult to achieve depending on conditions such as the radius of curvature of the surface of the outermost lens 1 and the viscosity of the foreign matter 70. Therefore, as a measure to prevent foreign matter 70 from accumulating in the center of the outermost lens 1, for example, it is possible to increase the radius of curvature of the surface of the outermost lens 1 to reduce the force Fc directed toward the center of the outermost lens 1. When increasing the radius of curvature of the surface of the outermost lens 1, for example, it is preferable that the radius of curvature of the surface of the outermost lens 1 be 24 mm or more. Furthermore, by setting the radius of curvature of the outermost lens 1 surface to 24 mm or more, the standard viscosity liquid JS100 (kinematic viscosity 100.8 mm) ２ This can suppress the accumulation of highly viscous foreign matter (at / s) in the center of the outermost lens 1.

[0026] Alternatively, as another measure, it is conceivable to change the direction of the force acting on the foreign object 70 from a force Fc directed toward the center of the outermost lens 1 to a force Fd directed toward the outside of the outermost lens 1, as shown in Figure 2. In the vibration device 10 according to this embodiment, the outermost lens 1 is vibrated by vibration A as shown in Figure 1 in order to change the direction of the force acting on the foreign object 70. The vibration component of vibration A includes a vibration component in the X direction in addition to a vibration component in the Z direction. The principle by which the outermost lens 1 can be vibrated by vibration A to change the direction of the force acting on the foreign object 70 to a force Fd directed toward the outside of the outermost lens 1 will be explained.

[0027] Before that, let's explain the principle by which the force Fc directed toward the center of the outermost lens 1 is generated. Figure 3 is a schematic diagram to explain the relationship between the vibration component in the Z direction of the outermost lens 1 and the force acting on the foreign object 70. Figure 3(a) shows the force acting on the foreign object 70 when the phase of vibration B is 0 degrees. On the other hand, Figure 3(b) shows the force acting on the foreign object 70 when the phase of vibration B is 180 degrees. Note that the vibration component of vibration B is only the vibration component in the Z direction. Also, in Figure 3, the tangential direction at the position of the outermost lens 1 to which the foreign object 70 is attached is the x direction, the normal direction to the tangential direction is the z direction, and the direction of the arrow in the figure is the positive direction.

[0028] When the outermost lens 1 is vibrated with vibration B at a phase of 0 degrees, as shown in Figure 3(a), a force Fx is generated that tries to keep the foreign object 70 in the same position due to the vibration component (-x1) in the x direction of vibration B. On the other hand, when the outermost lens 1 is vibrated with vibration B at a phase of 180 degrees, as shown in Figure 3(b), a force (-Fx) is generated that tries to keep the foreign object 70 in the same position due to the vibration component (x1) in the x direction of vibration B. Thus, when the outermost lens 1 is vibrated with vibration B, forces Fx of the same magnitude in opposite directions are generated due to the phase, so the average force acting on the foreign object 70 over one period of vibration B is 0 (zero).

[0029] However, when the outermost lens 1 is vibrated, the frictional force Ff generated between the outermost lens 1 and the foreign object 70 changes in magnitude depending on the phase. Specifically, when the outermost lens 1 is vibrated with vibration B at phase 0, as shown in Figure 3(a), the outermost lens 1 is pressed against the foreign object 70, so a large frictional force (-Ffa) is generated in the opposite direction to the force Fx. On the other hand, when the outermost lens 1 is vibrated with vibration B at phase 180, as shown in Figure 3(b), the outermost lens 1 is pulled away from the foreign object 70, so a small frictional force Ffb (|Ffb| < |-Ffa|) is generated in the opposite direction to the force (-Fx). Therefore, when the outermost lens 1 is vibrated with vibration B, frictional forces Ff of different magnitudes are generated depending on the phase, so when the force acting on the foreign object 70 is averaged over one period of vibration B, a force of frictional force (-Ffa) + frictional force Ffb remains. This remaining force generates a force Fc directed toward the center of the outermost lens 1.

[0030] Therefore, in the vibration device 10 according to this embodiment, as shown in Figure 1, the outermost lens 1 is vibrated by vibration A, and the direction of the force acting on the foreign object 70 is changed to a force Fd directed outward from the outermost lens 1. The principle will be explained using a diagram. Figure 4 is a schematic diagram for explaining the relationship between the vibration component of the outermost lens 1 and the force acting on the foreign object 70 in the vibration device 10 according to Embodiment 1. Figure 4(a) shows the force acting on the foreign object 70 when the phase of vibration A is 0 degrees. On the other hand, Figure 4(b) shows the force acting on the foreign object 70 when the phase of vibration A is 180 degrees. Note that the vibration component of vibration A includes a vibration component in the X direction in addition to the vibration component in the Z direction. Also, in Figure 4, the tangential direction at the position of the outermost lens 1 to which the foreign object 70 is attached is the x direction, the normal direction to the tangential direction is the z direction, and the direction of the arrow in the figure is the positive direction.

[0031] When the outermost lens 1 is vibrated with vibration A at a phase of 0 degrees, as shown in Figure 4(a), a force (-Fx) is generated that causes the foreign object 70 to remain in the same position due to the vibration component x2 in the x direction of vibration A. On the other hand, when the outermost lens 1 is vibrated with vibration A at a phase of 180 degrees, as shown in Figure 4(b), a force Fx is generated that causes the foreign object 70 to remain in the same position due to the vibration component (-x2) in the x direction of vibration A. Thus, when the outermost lens 1 is vibrated with vibration A, forces Fx of the same magnitude in opposite directions are generated due to the phase, so the average force acting on the foreign object 70 during one period of vibration A is 0 (zero).

[0032] However, when the outermost lens 1 is vibrated, the frictional force Ff generated between the outermost lens 1 and the foreign object 70 is such that, as shown in Figure 4(a), when the outermost lens 1 is pressed against the foreign object 70, a large frictional force Ffa is generated in the opposite direction to the force (-Fx). On the other hand, when the outermost lens 1 is vibrated with vibration A of a phase of 180 degrees, as shown in Figure 4(b), the outermost lens 1 is pulled away from the foreign object 70, so a small frictional force (-Ffb) (|-Ffb| < |Ffa|) is generated in the opposite direction to the force Fx. Therefore, when the outermost lens 1 is vibrated with vibration A, frictional forces Ff of different magnitudes are generated depending on the phase, so when the force acting on the foreign object 70 is averaged over one period of vibration A, a force of frictional force Ffa + frictional force (-Ffb) remains. This remaining force generates a force Fd directed outward from the outermost lens 1.

[0033] As with the vibration device 10, the outermost lens 1 is vibrated with vibration A that includes vibration components in the X direction in addition to vibration components in the Z direction, thereby reversing the force Fc directed toward the center of the outermost lens 1 into a force Fd directed toward the outside of the outermost lens 1, and preventing foreign matter 70 from accumulating in the center of the outermost lens 1. Although it has been explained that the vibration device 10 vibrates the outermost lens 1 with vibration A that includes vibration components in the X direction in addition to vibration components in the Z direction, the vibration components included in the vibration of the outermost lens 1 are not limited to vibration components in the X direction. A vibration component that can prevent foreign matter 70 from accumulating in the center of the outermost lens 1 only needs to include at least a vibration component in the direction of the optical axis (Z direction) of the light passing through the outermost lens 1 from the side of the vibrating body 3 (first component) and vibration components in directions perpendicular to the optical axis (X direction, Y direction) (second component).

[0034] Specifically, the vibration component that can prevent foreign matter 70 from accumulating in the center of the outermost lens 1 includes vibration components in the X or Y direction in addition to the Z direction vibration component, or includes vibration components in the X and Y directions in addition to the Z direction vibration component. Thus, the vibration device 10 according to this embodiment only needs to be able to vibrate the outermost lens 1 with vibrations that include vibration components in directions other than the Z direction vibration component. In the vibration device 10, in order to vibrate the outermost lens 1 with vibrations that include vibration components in directions other than the Z direction vibration component, for example, the piezoelectric element 5 is divided into multiple parts, and the vibrating body 3 is vibrated with vibrations of different magnitudes by each piezoelectric element 5.

[0035] (Embodiment 2) In Embodiment 2, a configuration is described in which the outermost lens is vibrated by vibrations that include vibration components other than the vibration component in the Z direction, by devising the shape of the vibrating body. Figure 5 is a perspective view of the vibrating device 10A according to Embodiment 2. In the vibrating device 10A, the same reference numerals are used for components that are the same as those in the vibrating device 10 shown in Figure 1, and their descriptions are not repeated.

[0036] The vibration device 10A differs in the shape of the spring portion (third cylindrical portion) of the vibrating body 3A. The spring portion connecting the first cylindrical portion 31 and the second cylindrical portion 32 of the vibrating body 3A is composed of two parts with different natural vibration directions. Specifically, the vibrating body 3A combines a spring portion 33A (first portion) whose main natural vibration direction is the Z direction and a spring portion 33B (second portion) which includes natural vibration directions other than the Z direction, in the circumferential direction of the cylinder. As shown in Figure 5, the spring portion 33A is a plate-shaped member which is half the shape of a cylinder. On the other hand, as shown in Figure 5, the spring portion 33B is a column-shaped (tuning fork-shaped) member with a Y-shape positioned downwards.

[0037] Figure 6 is a schematic diagram illustrating the displacement that occurs in the vibration device 10A according to Embodiment 2. The schematic diagram in Figure 6 shows the simulation results of the displacement that occurs in the vibration device 10A when a voltage is applied to the piezoelectric element 5 to vibrate the outermost lens 1. In Figure 6, the magnitude of the displacement is indicated by the intensity of the hatching, with darker hatching indicating areas of large displacement. In the vibration device 10 shown in Figure 6, the displacement of the largest displacement is approximately 8 μm.

[0038] From Figure 6, it can be seen that the vibration device 10A includes a vibration component in the X direction in addition to the vibration component in the Z direction of the outermost lens 1. Specifically, in the outermost lens 1 shown in Figure 6, the vibration component at point C includes both a vibration component in the Z direction and a vibration component in the X direction. In this way, by combining spring sections 33A and 33B which have different natural vibration directions, the vibration device 10A can include a vibration component in the X direction in addition to the vibration component in the Z direction of the outermost lens 1.

[0039] The proportion of the vibration component in the X direction included in the vibration component of the outermost lens 1 changes depending on the coupling coefficient of the spring parts 33A and 33B, which have different natural vibration directions. Figure 7 is a graph illustrating the relationship between the proportion of vibration components and the coupling coefficient. In Figure 7, the horizontal axis is the ratio of the spring parts 33A and 33B, which have different natural vibration directions, the left vertical axis is the proportion of the vibration component in the X direction, and the right vertical axis is the coupling coefficient. As shown in the solid line graph in Figure 7, the ratio of the vibration component in the X direction to the vibration component in the Z direction increases in the vibration device 10A. Specifically, when the ratio of the spring part 33B to the spring part 33A is approximately 0.83, the ratio of the vibration component in the X direction to the vibration component in the Z direction is approximately 50%. Also, as shown in the dashed line graph in Figure 7, the coupling coefficient of the vibration device 10A increases as the ratio of the spring part 33B to the spring part 33A increases.

[0040] As described above, the vibrating body 3A according to this embodiment is cylindrical in shape and includes a first cylindrical portion 31 that is in contact with the outermost lens 1, a second cylindrical portion 32 on which a piezoelectric element 5 is provided, and a spring portion (third cylindrical portion) that connects the first cylindrical portion 31 and the second cylindrical portion 32. The spring portion includes a spring portion 33A that connects the first cylindrical portion 31 and the second cylindrical portion 32 with a plate-shaped member in the circumferential direction of the cylinder, and a spring portion 33B that connects the first cylindrical portion 31 and the second cylindrical portion 32 with a columnar member. As a result, the vibrating device 10A can include a vibration component in the X direction in addition to the vibration component in the Z direction in the vibration component of the outermost lens 1.

[0041] (Embodiment 3) In the vibration devices 10 and 10A according to the above-described embodiment, the displacement of the outermost lens 1 is not tilted in a plane perpendicular to the optical axis direction. In this embodiment, a vibration device in which the displacement of the outermost lens 1 is tilted in a plane perpendicular to the optical axis direction will be described. Figure 8 is a cross-sectional view of the imaging device 100A according to Embodiment 3. In the imaging device 100A, the same reference numerals are used for components similar to those in the imaging device 100 shown in Figure 1, and their descriptions will not be repeated.

[0042] The vibration device 10 shown in Fig. 8 adds mass to at least a part of the vibrating body 3 in order to incline the displacement amount of the outermost lens 1 in a plane (X - Y plane) orthogonal to the optical axis direction (Z direction). Specifically, as shown in Fig. 8, the vibration device 10 provides a weight 4 on the first cylindrical portion 31. The weight 4 is not arranged on the entire circumference of the first cylindrical portion 31 but is provided only on a part thereof. For example, it has a semi - circular shape that extends half - way around the circumferential direction of the first cylindrical portion 31.

[0043] The weight 4 is not limited to a material as long as it can add mass to a part of the first cylindrical portion 31, and it may be the same material as the first cylindrical portion 31 or a different material. If the specific gravity of the material of the weight 4 is greater than the specific gravity of the material of the first cylindrical portion 31, the weight 4 can be miniaturized, and the space for providing the weight 4 can be reduced. Also, the weight 4 may be composed of a plurality of pieces, and may be formed integrally with the first cylindrical portion 31 or formed individually.

[0044] By providing the weight 4 on a part of the first cylindrical portion 31, when the outermost lens 1 is vibrated, the vibration device 10 can incline the displacement amount between the side where the weight 4 is provided and the side where the weight 4 is not provided. As shown in Fig. 8, in the vibration device 10, the displacement amount of the outermost lens 1 on the side where the weight 4 is provided is small, and conversely, the displacement amount of the outermost lens 1 on the side where the weight 4 is not provided is large. The vibration device 10 vibrates the outermost lens 1 with a vibration A that includes a vibration component in the X direction in addition to the vibration component in the Z direction. Therefore, among the vibration components of the outermost lens 1, the X direction (the direction of the second component) is the same as the direction (the inclination direction of the displacement) from the side where the displacement amount of the outermost lens 1 is small to the side where it is large, as shown in Fig. 8.

[0045] As a result, the vibration device 10 can direct the force acting on the foreign matter 70 to the outside of the outermost lens 1, and further tilt and vibrate the outermost lens 1 to slide off the attached foreign matter 70 from the outermost lens 1 and remove it. In particular, by attaching the vibration device 10 to the imaging device 100 such that at least one of the X direction (the direction of the second component) of the vibration component and the inclination direction of the displacement of the outermost lens 1 is the direction of gravity, it becomes easier for the attached foreign matter to slide off from the outermost lens 1. It is more preferable that a water-repellent or hydrophilic coating material is applied to the surface of the outermost lens 1.

[0046] FIG. 9 is a schematic diagram for explaining the displacement generated in the vibration device 10 according to Embodiment 3. In FIG. 9, the magnitude of the displacement is indicated by the density of the hatching, and the portion with darker hatching indicates the portion with a larger displacement. In the vibration device 10 shown in FIG. 9, the displacement of the portion with the largest displacement is about 8 μm. It can be seen from FIG. 9 that a displacement inclination with the largest displacement due to vibration occurs at the end of the outermost lens 1. Specifically, the displacement generated in the vibration device 10 is large on the lower side of FIG. 9 and small on the upper side of FIG. 9. The direction from the upper side to the lower side of FIG. 9 is the direction of gravity.

[0047] (Other modification examples) In order to vibrate the outermost lens 1 with vibration A including a vibration component in the X direction in addition to the vibration component in the Z direction like the vibration device 10, it is necessary to give the piezoelectric element 5 an unbalanced property in the X direction. Therefore, instead of giving the piezoelectric element 5 itself an unbalanced property, an X-direction vibration component may be imparted to the vibration component of the vibrating body 3. Specifically, by providing a plate thickness difference in the X direction with respect to the central axis of the vibrating body 3, a difference is provided in the Young's modulus of the vibrating body 3 in the X direction. Alternatively, by providing at least one groove or hole in the spring portion 33 of the vibrating body 3, a difference is provided in the Young's modulus of the vibrating body 3 in the X direction.

[0048] The configurations described in the vibration devices according to the foregoing embodiments can be combined as appropriate. Further, the imaging device according to the foregoing embodiments may include a camera, LiDAR, Radar, etc. Furthermore, a plurality of imaging devices may be arranged side by side.

[0049] 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 image sensor arranged so that the translucent material is in the field of view, and where it is necessary to remove foreign matter from the translucent material.

[0050] In the imaging device according to the above-described embodiment, it was explained that a means for removing foreign matter adhering to the surface of the outermost lens 1 is to vibrate the outermost lens 1 using vibrators 3 and 3A to remove foreign matter adhering to the surface. However, the means for removing foreign matter adhering to the surface of the outermost lens 1 is not limited to this, and the imaging device according to the above-described embodiment may be further provided with a means for physically removing foreign matter with a wiper, for example, or a means for removing foreign matter by discharging a cleaning substance (cleaning liquid, air, etc.) with a discharge device.

[0051] (Aspects) (1) The vibration device according to the present disclosure comprises a light-transmitting body that transmits light of a predetermined wavelength, a vibrating body that is in contact with the light-transmitting body and vibrates the light-transmitting body, and a vibration source provided on the vibrating body, wherein the vibration component of the light-transmitting body based on the vibration source includes at least a first component in the direction of the optical axis of the light passing through the light-transmitting body from the side of the vibrating body, and a second component in a direction perpendicular to the optical axis.

[0052] As a result, the vibration device according to this disclosure has a vibration component of the transparent material based on the vibration source that includes at least a first component in the direction of the optical axis of light passing through the transparent material from the side of the vibrating material, and a second component in a direction perpendicular to the optical axis, thereby preventing foreign matter from accumulating in the central part of the transparent material due to vibration and not obstructing the field of view.

[0053] (2) In the vibrating device described in (1), the amount of displacement of the light-transmitting material is inclined in a plane perpendicular to the optical axis.

[0054] (3) In the vibration device described in (2), the direction of the second component of the vibration of the transparent material is the same as the direction in which the displacement of the transparent material moves from the smaller side to the larger side.

[0055] (4) In the vibration device described in any one of items (1) to (3), the direction of the second component of the vibration of the transparent material is the same as the direction of gravity.

[0056] (5) In the vibrating device described in any one of items (1) to (4), the radius of curvature of the surface of the transparent material is 24 mm or more.

[0057] (6) In the vibration device described in any one of items (1) to (5), the vibrating body is cylindrical in shape and includes a first cylindrical portion in contact with a translucent body, a second cylindrical portion on which a vibration source is provided, and a spring portion connecting the first cylindrical portion and the second cylindrical portion and having an S-shaped cross-section.

[0058] (7) In the vibration device described in any one of paragraphs (1) to (5), the vibrating body is cylindrical in shape and includes a first cylindrical portion in contact with a translucent body, a second cylindrical portion on which a vibration source is provided, and a third cylindrical portion connecting the first cylindrical portion and the second cylindrical portion, wherein the third cylindrical portion includes a first portion connecting the first cylindrical portion and the second cylindrical portion with a plate-shaped member in the circumferential direction of the cylinder, and a second portion connecting the first cylindrical portion and the second cylindrical portion with a column-shaped member.

[0059] (8) In the vibration device described in any one of items (1) to (7), the vibration source is a piezoelectric element.

[0060] (9) The imaging device relating to this disclosure comprises a vibrating device as described in any one of paragraphs (1) to (8), and an image sensor arranged such that the light-transmitting material is in the direction of the field of view.

[0061] The imaging apparatus described in (10)(9) is further provided with a dispensing device for dispensing a cleaning solution onto the surface of the light-transmitting body.

[0062] In the imaging apparatus described in (11), (9), or (10), the surface of the light-transmitting body is coated with a water-repellent coating material.

[0063] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of this disclosure is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope of the claims are intended to be included.

[0064] 1 Outermost lens, 2 Housing, 2a First part, 2b End, 2c Second part, 2d Third part, 2e, 4 Weight, 3, 3A Vibrator, 5 Piezoelectric element, 6 Image sensor, 8 Bracket, 10, 10A Vibration device, 20 Sensor device, 21 Retainer, 31 First cylindrical part, 32 Second cylindrical part, 33, 33A, 33B Spring part, 70 Foreign object, 100, 100A Imaging device.

Claims

1. A vibrating device comprising: a light-transmitting body that transmits light of a predetermined wavelength; a vibrating body that is in contact with the light-transmitting body and vibrates the light-transmitting body; and a vibration source provided on the vibrating body, wherein the vibration component of the light-transmitting body based on the vibration source includes at least a first component in the direction of the optical axis of light passing through the light-transmitting body from the side of the vibrating body, and a second component in a direction perpendicular to the optical axis.

2. The vibration device according to claim 1, wherein the amount of displacement of the light-transmitting material is inclined in a plane perpendicular to the optical axis direction.

3. The vibration device according to claim 2, wherein the direction of the second component of the vibration components of the transparent material is the same as the direction in which the displacement of the transparent material moves from the smaller side to the larger side.

4. The vibration device according to any one of claims 1 to 3, wherein the direction of the second component of the vibration components of the transparent material is the same as the direction of gravity.

5. The vibration device according to any one of claims 1 to 4, wherein the radius of curvature of the surface of the translucent material is 24 mm or more.

6. The vibrating body is cylindrical in shape and includes a first cylindrical portion in contact with the light-transmitting body, a second cylindrical portion on which the vibration source is provided, and a spring portion connecting the first cylindrical portion and the second cylindrical portion and having an S-shaped cross-section, according to any one of claims 1 to 5.

7. The vibrating body is cylindrical in shape and includes a first cylindrical portion in contact with the light-transmitting body, a second cylindrical portion for providing the vibration source, and a third cylindrical portion connecting the first cylindrical portion and the second cylindrical portion, wherein the third cylindrical portion includes a first portion connecting the first cylindrical portion and the second cylindrical portion with a plate-shaped member in the circumferential direction of the cylinder, and a second portion connecting the first cylindrical portion and the second cylindrical portion with a column-shaped member, according to any one of claims 1 to 5.

8. The vibration device according to any one of claims 1 to 7, wherein the vibration source is a piezoelectric element.

9. An imaging device comprising a vibrating device according to any one of claims 1 to 8, and an imaging sensor arranged such that the light-transmitting body is in the direction of the field of view.

10. The imaging apparatus according to claim 9, further comprising a dispensing device for dispensing a cleaning solution onto the surface of the light-transmitting body.

11. The imaging apparatus according to claim 9 or claim 10, wherein the surface of the light-transmitting body is coated with a water-repellent coating material.

Images