Vibration device and imaging device

Abstract

This disclosure provides: a vibration device having a structure that makes it less likely for foreign matter to adhere to a portion thus causing a deterioration in vibration performance; and an imaging device. A vibration device (10) comprises: an outermost layer lens (1) (translucent body) that transmits light of a prescribed wavelength; a vibrating body (3) that is in contact with the outermost layer lens (1) and vibrates the outermost layer lens (1); a piezoelectric element (5) provided to the vibrating body (3); a plate spring (2a) and a retainer (2b) (extending parts) that extend outward from a side wall of the vibrating body (3) that is a cylindrical body; and a cover part (7) that covers at least a part of the plate spring (2a) and 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 equipped 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] In the vibration device described in Patent Document 1, a piezoelectric element is attached to a flange portion of a light-transmitting body to vibrate the light-transmitting body. The vibration device employs a configuration in which the piezoelectric element is sandwiched between a drip-proof seal to fix the piezoelectric element to the flange portion, and the drip-proof seal is then fixed to a support frame. Therefore, there is a risk that vibrations will be transmitted from the drip-proof seal, which is in direct contact with the piezoelectric element, to the support frame, resulting in a deterioration in vibration performance.

[0006] Furthermore, in the vibration device described in Patent Document 1, it is possible that foreign matter such as water or dust may adhere to the drip-proof seal, and if foreign matter adheres to the drip-proof seal, the adhered foreign matter may inhibit the vibration of the piezoelectric element, resulting in a risk of a decrease in vibration performance.

[0007] Therefore, an object of the present disclosure is to provide a vibration device and an imaging device that have a structure that makes it difficult for foreign matter to adhere to parts that may cause a decrease in vibration performance.

[0008] A vibration device according to one embodiment of 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, an extension portion that extends outward from the side wall of the vibrating body, which is a cylindrical body, and a cover portion that covers at least a portion of the extension portion and the vibrating body.

[0009] 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.

[0010] According to the present disclosure, by providing a cover portion so as to prevent foreign matter from adhering to at least a portion of the extension portion and the vibrating body, vibration performance is not reduced.

[0011] 1 is a perspective view of an imaging device according to embodiment 1. FIG. 2 is a half sectional view of a vibration device according to embodiment 1. FIG. 3 is a diagram for explaining the relationship between the distance from a starting point and the displacement. FIG. 4 is a schematic diagram for explaining the displacement occurring in the vibration device according to embodiment 1. FIG. 4 is a diagram for explaining the relationship between the amount of displacement of the outermost lens (translucent body) and the load. FIG. 5 is a diagram for explaining the relationship between the amount of displacement of the outermost lens (translucent body) and the Young's modulus of the intermediate member. FIG. 5 is a half sectional view of a vibration device according to modified example 1. FIG. 6 is a half sectional view of a vibration device according to modified example 2. FIG. 7 is a half sectional view of a vibration device according to modified example 3. FIG. 8 is a half sectional view of a vibration device according to modified example 4. FIG. 9 is a half sectional view of a vibration device according to modified example 5. FIG. 10 is a half sectional view of a vibration device according to modified example 6. FIG. 11 is a diagram for explaining the attachment position of a cover unit. FIG. 12 is a diagram for explaining different attachment positions of the cover unit. FIG. 13 is a half sectional view of a vibration device according to embodiment 2. FIG. 14 is a schematic diagram for explaining the displacement occurring in the vibration device according to embodiment 2. FIG. 15 is a half sectional view of a vibration device according to a modified example of embodiment 2. FIG. 16 is a half sectional view of a vibration device according to embodiment 3. FIG. 17 is a diagram for explaining the relationship between the amount of displacement of the outermost lens (translucent body) and the dimensions of the intermediate member. FIG. 18 is a half sectional view of a vibration device according to a modified example of embodiment 3. FIG. 10 is a perspective view of a vibration device according to a fifth embodiment.

[0012] 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.

[0013] (Embodiment 1) Fig. 1 is a perspective view of an imaging device 100 according to embodiment 1. Fig. 2 is a half-sectional view of a vibration device 10 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 dashed-dotted line in Fig. 2 indicates a portion passing through the central axis of the vibration device 10. 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, a piezoelectric element 5, and a cover 7. 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.

[0014] 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 form 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 (not shown). The circuit board 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 to drive the piezoelectric element 5. The circuit board 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).

[0015] 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.

[0016] An end of the outermost lens 1 is in contact with an end of a leaf spring 2a extending from the housing 2. An end of the leaf spring 2a is a retainer 2b, which is in contact with the outermost lens 1 and the vibrating body 3. An adhesive, for example, is filled between the retainer 2b and the outermost lens 1 and the vibrating body 3. The housing 2, leaf spring 2a, and retainer 2b may be formed integrally or separately. Furthermore, the vibrating device 10 is in contact with the vibrating body 3 to vibrate the outermost lens 1. The housing 2 and the vibrating body 3 are made of, for example, stainless steel (SUS304, SUS420, SUS440), etc.

[0017] 2, the vibrating body 3 is a cylindrical body and is composed of a connecting portion 31 (first portion) that contacts the outermost lens 1, a vibrating portion 32 (second portion) that has the piezoelectric element 5 provided thereon, and a supporting portion 33 (third portion) that connects the connecting portion 31 and the vibrating portion 32. The cross section of the supporting portion 33 is S-shaped. An inner lens (not shown) may be placed inside the cylinder of the vibrating body 3.

[0018] Connection part 31 is a cylindrical part that is elongated in the axial direction (Z direction) of the cylindrical body, and its end comes into contact with the peripheral edge of outermost lens 1 to transmit the vibration of vibrating body 3 to outermost lens 1. A recess is provided in connection part 31 to stably hold outermost lens 1 in the radial direction (X and Y directions) of the cylindrical body.

[0019] The vibrating 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 connecting portion 31 and the supporting portion 33. This makes it easier to transmit the vibration of the piezoelectric element 5 to the outermost lens 1 more efficiently.

[0020] The support portion 33 is a portion that supports the connection portion 31 and transmits vibrations of the vibration portion 32 to the connection portion 31. The connection portion 31, the vibration portion 32, and the support portion 33 may be formed integrally or separately.

[0021] The piezoelectric element 5 is provided on the surface of the vibrating section 32 opposite to the side in contact with the outermost lens 1. The piezoelectric element 5 has a hollow circular shape 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

[0022] 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 direction in the figure) by the support part 33 of the vibrating body 3, causing the outermost lens 1 to vibrate in the Z direction.

[0023] When the vibrating body 3 vibrates the outermost lens 1, the retainer 2b, which is in contact with the outermost lens 1 and the vibrating body 3, and the leaf spring 2a, which is connected to the retainer 2b, also vibrate. The leaf spring 2a and the retainer 2b are extensions that extend outward from the side wall of the vibrating body 3, and the displacement caused by the vibration of the vibrating body 3 decreases toward the outside. Specifically, the displacement of the leaf spring 2a and the retainer 2b will be described starting from the position where the vibrating body 3 and the retainer 2b contact each other. Figure 3 is a diagram for explaining the relationship between the distance from the starting point and the displacement.

[0024] As shown in FIG. 3B, the imaging device 100 is mounted on a device (e.g., a vehicle) so that the optical axis direction (the direction of the dashed line) is approximately 90 degrees relative to the direction of gravity (the downward direction in the figure). Therefore, raindrops and other moisture-rich foreign matter adhering to the outermost lens 1 or the leaf spring 2a (extension) are moved downward in the figure by gravity G. However, when the outermost lens 1 or the leaf spring 2a are displaced by the vibration of the vibrating body 3, foreign matter W adhering to the leaf spring 2a, which vibrates at a displacement that does not cause atomization, moves toward the larger displacement. This is because the force that deforms the foreign matter W due to the vibration of the vibrating body 3 differs depending on the displacement, causing a deviation in the center of gravity of the foreign matter W, resulting in a force P that moves the foreign matter W toward the larger displacement.

[0025] As shown in Figure 3(a), the displacement of the leaf spring 2a and the retainer 2b decreases with increasing distance from the starting point. Therefore, the force P acting on the foreign object W due to the vibration of the vibrating body 3 is generated in the direction of the starting point, i.e., in the opposite direction to gravity G. As a result, the foreign object W attached to the leaf spring 2a continues to remain at a position where the force P acting on the foreign object W and gravity G are balanced. If the foreign object W continues to remain on the leaf spring 2a, the attached foreign object W may inhibit the vibration of the piezoelectric element 5, resulting in a risk of degrading vibration performance.

[0026] Therefore, the vibration device 10 is provided with a cover portion 7 that covers the leaf spring 2a to prevent foreign matter from adhering to the leaf spring 2a. The cover portion 7 is held on the outer surface of the housing 2 (a surface perpendicular to the leaf spring 2a) with a gap provided so that it does not come into direct contact with the leaf spring 2a that vibrates due to the vibrating body 3. Therefore, the cover portion 7 itself is not displaced by the vibration of the vibrating body 3, so foreign matter does not remain on the surface of the cover portion 7, and there is no risk that attached foreign matter will inhibit the vibration of the piezoelectric element 5 and reduce vibration performance. It is sufficient for the cover portion 7 to cover the vibrating body 3 and at least a portion of the leaf spring 2a (extension portion) that is displaced by the vibration of the vibrating body 3.

[0027] FIG. 4 is a schematic diagram illustrating the displacement occurring in the vibration device 10 according to the first embodiment. As can be seen from FIG. 4 , the vibration body 3 causes the support portion 33 to elastically deform like a spring, thereby significantly displacing the outermost lens 1 in the Z direction. The vibration of the vibration body 3 also causes the leaf spring 2a in contact with the outermost lens 1 to elastically deform. Also, as can be seen from FIG. 4 , the vibration body 3 has a vibration node N at the center of the S-shaped cross section of the support portion 33. The vibration of the vibration body 3 maximizes the displacement of the outermost lens 1, while the displacement at the center (node) of the support portion 33 is small. Note that in FIG. 4 , the magnitude of displacement is indicated by the shade of hatching, with darker hatching indicating areas with greater displacement, with the outermost lens 1 having the greatest displacement. Meanwhile, the displacement is smallest at the center of the support portion 33 and the housing 2.

[0028] The cover part 7 is held by the housing 2 with the smallest displacement. Specifically, the conditions under which the cover part 7 can be held will be described. To meet these conditions, it is necessary that the location does not impede the vibration of the outermost lens 1 even when an external force is applied. To evaluate the locations that do not impede the vibration of the outermost lens 1, loads were applied to the four corners of the housing 2 of the vibration device 10 to measure the amount of displacement of the outermost lens 1. Figure 5 is a diagram for explaining the relationship between the amount of displacement of the outermost lens 1 (translucent body) and the load.

[0029] Figure 5(a) shows the change in the amount of displacement of the outermost lens 1 when weights of 0 g to 800 g are placed on the four corners of the housing 2. The horizontal axis of Figure 5(a) shows the mass (g) of the weight, and the vertical axis shows the rate of change in the amount of displacement when the amount of displacement of the outermost lens 1 when a 0 g weight is placed is 100%. When weights were placed on the four corners of the housing 2, the amount of displacement of the outermost lens 1 remained almost unchanged regardless of the mass of the weight.

[0030] In Figure 5(b), the displacement of the vibration device 10 was determined by simulation. In Figure 5(b), the magnitude of displacement is indicated by the shade of hatching, with darker hatching indicating areas with greater displacement. The outermost lens 1 had the greatest displacement, at approximately 40 μm. Meanwhile, the housing 2 had the smallest displacement, at approximately 0.8 μm. The displacement at the four corners of the housing 2 where the weights were placed was approximately 0.8 μm, which is approximately 2% of the maximum displacement of the outermost lens 1. Therefore, if the lightly hatched areas in Figure 5(b) are 0.8 μm or less, the conditions for being able to hold the cover 7 are met. In other words, the cover 7 only needs to be held in areas where the displacement is less than a predetermined value (for example, 2% of the maximum displacement).

[0031] The cover portion 7 provides a gap between the leaf spring 2a and the retainer 2b when the displacement due to vibration of the vibrating body 3 is greater than a predetermined value (for example, 2% of the maximum displacement amount). The vibration device 10 provides intermediate members 71 and 72 to prevent foreign matter from entering the gap. The intermediate member 71 fills the gap between the cover portion 7 and the retainer 2b, and the intermediate member 72 fills the gap between the cover portion 7 and the leaf spring 2a. Therefore, the intermediate members 71 and 72 come into direct contact with the leaf spring 2a and the retainer 2b.

[0032] Because the intermediate members 71 and 72 are in direct contact with the leaf spring 2a and the retainer 2b, they are made of a material with a low Young's modulus, such as rubber, resin, or sponge, that does not impede the vibration of the piezoelectric element 5 or reduce vibration performance. It is preferable that the intermediate members 71 and 72 not only have the function of not reducing vibration performance, but also have other functions, such as waterproofing and sealing (capability). Figure 6 is a diagram illustrating the relationship between the displacement of the outermost lens 1 (translucent body) and the Young's modulus of the intermediate members 71 and 72. The horizontal axis of Figure 6 represents Young's modulus (GPa), and the vertical axis represents the rate of change in displacement when the displacement of the outermost lens 1 is 0% when the intermediate members 71 and 72 are not provided. As shown in Figure 6, if the Young's modulus of the intermediate members 71 and 72 is 1.0 GPa or less, the displacement of the outermost lens 1 will be 0% even when the gaps between the cover portion 7 and the leaf spring 2a and the retainer 2b are filled with the intermediate members 71 and 72. Therefore, if the intermediate members 71 and 72 of the vibration device 10 are made of a material with a Young's modulus of 1.0 GPa or less, the vibration of the piezoelectric element 5 will not be inhibited and the vibration performance will not be reduced.

[0033] (Variation 1) As shown in Fig. 2, in the vibration device 10, the gaps between the cover portion 7 and the leaf spring 2a and the retainer 2b are filled with intermediate members 71, 72. However, the vibration device may be provided with only the cover portion 7 as long as it makes it difficult for foreign matter to adhere to the leaf spring 2a. Fig. 7 is a half cross-sectional view of a vibration device 10a according to Variation 1. Note that in the vibration device 10a, components similar to those in the vibration device 10 shown in Fig. 2 are designated by the same reference numerals, and descriptions thereof will not be repeated.

[0034] The vibration device 10a includes a cover 7 that is held on the outer surface of the housing 2 with a gap provided so as not to come into direct contact with the leaf spring 2a. However, the vibration device 10a does not include an intermediate member in the gap between the cover 7 and the leaf spring 2a or the retainer 2b. The cover 7 is disposed so as to cover the leaf spring 2a, which at least makes it difficult for foreign matter to adhere to the leaf spring 2a.

[0035] (Modification 2) As shown in Fig. 7, the vibration device 10a has a gap between the cover portion 7 and the retainer 2b, but the vibration device may have a configuration in which the gap between the cover portion 7 and the retainer 2b is filled. Fig. 8 is a half cross-sectional view of a vibration device 10b according to Modification 2. Note that in the vibration device 10b, components similar to those of the vibration device 10 shown in Fig. 2 are designated by the same reference numerals, and descriptions thereof will not be repeated.

[0036] The vibration device 10b includes a cover 7 that is held on the outer surface of the housing 2 with a gap provided so as not to come into direct contact with the leaf spring 2a. Furthermore, the vibration device 10b includes an intermediate member 71 in the gap between the cover 7 and the retainer 2b. Therefore, the vibration device 10b can prevent foreign matter from entering the gap between the cover 7 and the leaf spring 2a using the intermediate member 71. It is preferable that the intermediate member 71 be made of a material with a Young's modulus of 1.0 GPa or less. Furthermore, the intermediate member 71 does not necessarily have to have one surface in contact with the leaf spring 2a as shown in FIG. 8 , and it does not have to have one surface in contact with the leaf spring 2a.

[0037] (Variation 3) As shown in Fig. 2, in the vibration device 10, the cover portion 7 is held by the side of the housing 2. However, as long as the cover portion 7 is held in a portion where the displacement is equal to or less than a predetermined value (for example, 2% of the maximum displacement), the vibration of the piezoelectric element 5 is not inhibited and the vibration performance is not reduced. Fig. 9 is a half cross-sectional view of a vibration device 10c according to Variation 3. Note that in the vibration device 10c, components similar to those of the vibration device 10 shown in Fig. 2 are designated by the same reference numerals, and their description will not be repeated.

[0038] The vibration device 10c includes a cover portion 7a that is held on the upper surface of the housing 2 (a surface parallel to the leaf spring 2a) with a gap provided so as not to come into direct contact with the leaf spring 2a. As shown in FIG. 4, the portion where the cover portion 7a is held is a portion where the displacement is equal to or less than a predetermined value. Therefore, the cover portion 7a covers the portion of the leaf spring 2a where the displacement is greater than the predetermined value, making it difficult for foreign matter to adhere to this portion. An intermediate member 71 may be provided in the gap between the cover portion 7a and the retainer 2b.

[0039] (Variation 4) As shown in Fig. 2, in the vibration device 10, the gaps between the cover portion 7 and the leaf spring 2a and the retainer 2b are filled with intermediate members 71 and 72. However, the vibration device may have no gaps between the cover portion 7 and the leaf spring 2a and the retainer 2b. Fig. 10 is a half cross-sectional view of a vibration device 10d according to Variation 4. Note that in the vibration device 10d, components similar to those of the vibration device 10 shown in Fig. 2 are designated by the same reference numerals, and descriptions thereof will not be repeated.

[0040] The vibration device 10d includes a cover 7b that directly contacts the leaf spring 2a. Because the cover 7b directly contacts the portion of the leaf spring 2a where the displacement is greater than a predetermined value, it is made of a material with a Young's modulus of 1.0 GPa or less. Therefore, the cover 7b of the vibration device 10d prevents foreign matter from adhering to the leaf spring 2a, does not impede the vibration of the piezoelectric element 5, and does not degrade the vibration performance.

[0041] (Variation 5) As shown in Fig. 7, the vibration device 10a has the cover portion 7 arranged substantially parallel to the leaf spring 2a. However, the vibration device may have the cover portion 7 inclined relative to the leaf spring 2a. Fig. 11 is a half cross-sectional view of a vibration device 10e according to Variation 5. Note that in the vibration device 10e, components similar to those of the vibration device 10 shown in Fig. 2 are designated by the same reference numerals, and descriptions thereof will not be repeated.

[0042] Vibration device 10e includes cover portion 7c that is held on the outer surface of housing 2 with a gap provided so as not to come into direct contact with leaf spring 2a. Furthermore, cover portion 7c is inclined from the outermost lens 1 side toward the side where it is held, and the position of the held cover portion 7c is lower than the position of the outermost lens 1 in the axial direction (Z direction) of the cylindrical body. By inclining cover portion 7c in this manner, foreign matter W flows along the inner surface of cover portion 7c (the surface facing leaf spring 2a) as shown in FIG. 11, and can be discharged through discharge hole 73 provided in cover portion 7c.

[0043] As shown in FIG. 11 , the vibration device 10e is preferably attached to a device (e.g., a vehicle) so that the axial direction (Z direction) of the cylindrical body is at approximately 90 degrees with respect to the direction of gravity G (downward in the figure). Furthermore, only the portion of the cover part 7c that is located on the lower side when attached to the device may be inclined. Furthermore, when a configuration in which the cover part 7c is inclined is adopted, it is preferable that the connection part 31 of the vibrating body 3 be elongated in the axial direction (Z direction) of the cylindrical body as shown in FIG. 11 . Furthermore, a water-repellent or hydrophilic coating material may be applied to the surface of the cover part 7c that faces the leaf spring 2a.

[0044] (Variation 6) As shown in Fig. 11, the vibration device 10e has the cover portion 7c inclined relative to the leaf spring 2a to facilitate the discharge of foreign matter. However, the vibration device may also have a guide portion for discharging foreign matter provided on the cover portion to facilitate the discharge of foreign matter. Fig. 12 is a half cross-sectional view of a vibration device 10f according to Variation 6. Note that in the vibration device 10f, components similar to those of the vibration device 10 shown in Fig. 2 are designated by the same reference numerals, and their description will not be repeated.

[0045] The vibration device 10f includes a cover 7d that is held on the outer surface of the housing 2 with a gap provided so as not to come into direct contact with the leaf spring 2a. Furthermore, the cover 7d has an uneven surface facing the leaf spring 2a and a guide 74 for discharging foreign matter. By providing the guide 74 on the cover 7d in this manner, foreign matter W flows along the guide 74 as shown in FIG. 12 and can be discharged through a discharge hole 73 provided in the cover 7d.

[0046] As shown in Fig. 12, the vibration device 10f is preferably attached to a device (e.g., a vehicle) so that the axial direction (Z direction) of the cylindrical body is at approximately 90 degrees with respect to the direction of gravity G (downward in the figure). The cover 7d may be provided with a guide portion 74 only on the portion that will be positioned on the lower side when attached to the device. Furthermore, the cover 7d may be inclined like the cover 7c shown in Fig. 11. A water-repellent or hydrophilic coating material may be applied to the surface of the cover 7d that faces the leaf spring 2a.

[0047] 7, the vibration device 10a holds the cover part 7 on the outer surface of the housing 2 with a gap provided so as not to come into direct contact with the leaf spring 2a. However, the cover part 7 does not have to be held by the housing 2. FIG. 13 is a diagram for explaining the attachment position of the cover part 7.

[0048] As shown in Fig. 13 , the cover part 7 is held on the vehicle body 90 with a gap provided so that it does not come into direct contact with the leaf spring 2a. The vehicle body 90 is part of the device to which the vibration device 10a is attached. By providing the cover part 7 on the vehicle body 90, the cover part 7 can be held in a part where the vibration of the vibration device 10a is not propagated. The cover part 7 is held between the housing 2 and the vehicle body 90.

[0049] The cover unit 7 is not limited to being held between the housing 2 and the vehicle body 90, but may be held only by the vehicle body. Fig. 14 is a diagram for explaining different attachment positions of the cover unit. As shown in Fig. 14, the cover unit 7e is held by the vehicle body 90 with a gap provided so that it does not come into direct contact with the leaf spring 2a. The housing 2 and the vehicle body 90 are directly connected, and the cover unit 7e is held only by the vehicle body 90.

[0050] (Embodiment 2) In the vibration device 10 according to embodiment 1, as shown in FIG. 2, it has been described that the leaf spring 2a and the retainer 2b are extensions that extend outward from the sidewall of the vibrating body 3. In embodiment 2, a vibration device in which the extensions are portions that extend directly from the vibrating body will be described. FIG. 15 is a half cross-sectional view of a vibration device 10A according to embodiment 2. Note that in the vibration device 10A, the same components as those in the vibration device 10 shown in FIG. 2 are denoted by the same reference numerals, and their description will not be repeated. Furthermore, the vibration device 10A can be combined with a sensor device 20 instead of the vibration device 10 shown in FIG. 1 to form an imaging device 100.

[0051] As shown in Figure 15, the vibrating body 3 is a cylindrical body and is composed of a connecting portion 31 (first portion) that contacts the outermost lens 1, a vibrating portion 32 (second portion) that has a piezoelectric element 5, and a supporting portion 33 (third portion) that connects the connecting portion 31 and the vibrating portion 32.

[0052] Connecting portion 31 is a cylindrical portion that contacts the underside of outermost lens 1, and transmits the vibration of vibrating body 3 to outermost lens 1. It has holding portion 31a to stably hold outermost lens 1 in the radial direction (X and Y directions) of the cylindrical body. Connecting portion 31 and holding portion 31a may be formed integrally, or may be formed separately and then combined.

[0053] The vibrating 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 connecting portion 31 and the supporting portion 33. The vibrating portion 32 also has a flange 32a (extension portion) that extends outward on the side surface thereof. The flange 32a is supported by the supporting portion 2c of the housing 2. The flange 32a and the supporting portion 2c are joined together, for example, with an adhesive.

[0054] 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 direction in the figure) by the support part 33 of the vibrating body 3, causing the outermost lens 1 to vibrate in the Z direction.

[0055] Fig. 16 is a schematic diagram for explaining displacement occurring in the vibration device 10A according to embodiment 2. As can be seen from Fig. 16, the vibration body 3 causes the support portion 33 to elastically deform like a spring, thereby significantly displacing the outermost lens 1 in the Z direction. Also, as can be seen from Fig. 16, the vibration body 3 also causes significant displacement of the connection portion 31, the holding portion 31a, the vibration portion 32, and the support portion 33. Note that in Fig. 16, the magnitude of displacement is indicated by the shade of hatching, with darker hatching indicating areas with greater displacement, with the outermost lens 1 having the greatest displacement. Meanwhile, the housing 2 has the smallest displacement.

[0056] Therefore, in the vibration device 10A, as shown in FIG. 15 , a cover 7f is provided to cover the vibrating body 3 to prevent foreign matter from adhering to the vibrating body 3. The cover 7f is supported on the outer surface of the housing 2 (a surface perpendicular to the flange 32a) with a gap provided so that it does not come into direct contact with the vibrating vibrating body 3. Therefore, the cover 7f itself is not displaced by the vibration of the vibrating body 3, so foreign matter does not remain on the surface of the cover 7f, and there is no risk that attached foreign matter will inhibit the vibration of the piezoelectric element 5 or reduce vibration performance. It is sufficient for the cover 7f to cover the vibrating body 3, including at least a portion of the flange 32a whose displacement is greater than a predetermined value (for example, 2% of the maximum displacement amount).

[0057] A gap is provided between the cover portion 7f and the holder portion 31a where the displacement due to vibration of the vibrating body 3 is greater than a predetermined value. The vibration device 10A includes an intermediate member 71a to prevent foreign matter from entering this gap. The intermediate member 71a fills the gap between the cover portion 7f and the holder portion 31a. Therefore, the intermediate member 71a is in direct contact with the holder portion 31a. Therefore, the intermediate member 71a is made of a material with a low Young's modulus (e.g., a material with a Young's modulus of 1 GPa or less), such as rubber, resin, or sponge, so as not to impede the vibration of the piezoelectric element 5 or reduce vibration performance. It is preferable that the intermediate member 71a not only has the function of not reducing vibration performance, but also has other functions such as waterproofing and sealing (ability to be covered).

[0058] (Modification) Furthermore, an intermediate member may be provided in the gap between the cover portion 7f and the vibrating body 3. Fig. 17 is a half cross-sectional view of a vibration device 10B according to a modification of embodiment 2. Note that in vibration device 10B, the same components as those in vibration device 10A shown in Fig. 15 are denoted by the same reference numerals, and description thereof will not be repeated.

[0059] As shown in FIG. 17 , the vibration device 10B has a cover 7f that covers the vibrating body 3 to prevent foreign matter from adhering to the vibrating body 3. The cover 7f is held on the outer surface of the housing 2 with a gap so that it does not come into direct contact with the vibrating body 3. The vibration device 10B has intermediate members 71a and 72a to prevent foreign matter from entering the gap. The intermediate member 71a fills the gap between the cover 7f and the holder 31a, and the intermediate member 72a fills the gap between the cover 7f and the vibrating body 3. Therefore, the intermediate members 71a and 72a are made of a material with a small Young's modulus, such as rubber, resin, or sponge (for example, a material with a Young's modulus of 1 GPa or less), so as not to inhibit the vibration of the piezoelectric element 5 or to degrade vibration performance. It is preferable that the intermediate members 71a and 72a not only have the function of not reducing vibration performance but also have the functions of waterproofing and sealing (being able to be covered), etc.

[0060] (Embodiment 3) In the vibration device 10 according to embodiment 1, the gaps between the leaf spring 2 a and the cover 7 and the retainer 2 b are filled with intermediate members 71 and 72 to prevent foreign matter from entering the gaps. The intermediate member 71 fills the gap between the retainer 2 b (extension side) and the cover 7, and the intermediate member 72 fills the gap between the leaf spring 2 a (extension) and the cover 7. It has been explained that these intermediate members 71 and 72 are preferably made of a material with a Young's modulus of 1.0 GPa or less so as not to inhibit the vibration of the piezoelectric element 5 or reduce the vibration performance of the vibrating body 3. However, it is considered that the shape of the intermediate member in contact with the cover 7 may also affect the vibration performance of the vibrating body 3. Therefore, in embodiment 3, the shape of the intermediate member in contact with the cover 7 is further examined.

[0061] Figure 18 is a half-sectional view of a vibration device 10 according to embodiment 3. The vibration device 10 shown in Figure 18 has the same configuration as the vibration device 10 shown in Figure 2, and the same components are designated by the same reference numerals and detailed description thereof will not be repeated. The intermediate member 71 sandwiched between the retainer 2b and the cover portion 7 is considered to have a greater structural impact on the vibration performance of the vibrating body 3 than the intermediate member 72, as shown in Figure 18. Therefore, the relationship between the displacement amount of the outermost lens 1 and the shape of the intermediate member 71 will be examined. Figure 19 is a diagram for explaining the relationship between the displacement amount of the outermost lens 1 and the dimensions of the intermediate member 71.

[0062] For example, as shown in FIG. 18 , the intermediate member 71 has a thickness t (length in the X direction), a width w (length in the Z direction), and a contact area S with the cover portion 7. The thickness t corresponds to the length of the extension direction (length in the X direction) of the leaf spring 2 a (extension portion). The contact area S can be calculated by multiplying the inner circumference of the cover portion 7 by the thickness k of the cover portion 7. FIG. 19( a) shows the rate of change in the displacement of the outermost lens 1 when the thickness t of the intermediate member 71 is changed. The horizontal axis of FIG. 19( a) represents the thickness t (mm) of the intermediate member 71, and the vertical axis represents the rate of change in the displacement when the displacement of the outermost lens 1 is 0% when no cover portion 7 is provided. The graph shown in FIG. 19( a) also assumes that the width w of the intermediate member 71 is fixed at 2 mm. As shown in FIG. 19( a), in order to achieve a rate of change in the displacement of 10% or less, it is preferable to set the thickness t of the intermediate member 71 to 0.4 mm or less.

[0063] FIG. 19(b) shows the rate of change in the displacement of the outermost lens 1 when the thickness w of the intermediate member 71 is changed. The horizontal axis of FIG. 19(b) represents the thickness w (mm) of the intermediate member 71, and the vertical axis represents the rate of change in the displacement when the displacement of the outermost lens 1 is 0% when no cover portion 7 is provided. The graph shown in FIG. 19(b) also assumes that the thickness t of the intermediate member 71 is fixed at 0.4 mm. As shown in FIG. 19(b), changing the thickness w of the intermediate member 71 to 1 mm or 2 mm has almost no effect on the rate of change in the displacement. This means that the thickness w of the intermediate member 71 does not affect the vibration performance of the vibrating body 3.

[0064] 19(c) shows the rate of change in the displacement of the outermost lens 1 when the contact area S between the intermediate member 71 and the cover portion 7 is changed. The horizontal axis of FIG. 19(c) represents the contact area S (mm ２ 19(c) ) and the vertical axis indicates the rate of change in displacement when the displacement of the outermost lens 1 when the cover part 7 is provided is 0%. In the graph shown in FIG. 19(c) , the thickness t of the intermediate member 71 is fixed to 0.4 mm and the width w is fixed to 2 mm as a prerequisite. As shown in FIG. 19(c) , in order to keep the rate of change in displacement to 10% or less, the contact area S of the intermediate member 71 with the cover part 7 must be set to 60 mm ２ The intermediate members 71 and 72 may be made of a foamed material containing polypropylene (PP) as the main component, and may have a Young's modulus of 1.0 GPa or less, or may have a Young's modulus of more than 1.0 GPa.

[0065] The thickness t of the intermediate member 71 is set to 0.4 mm or less, and the contact area S of the intermediate member 71 with the cover portion 7 is set to 60 mm ２ If the following is done, it is possible to increase the thickness w (length in the Z direction) of the intermediate member 71 without affecting the vibration performance of the vibrating body 3. If the thickness w of the intermediate member 71 can be increased, it is possible to adopt a cylindrical vibration device in which the outermost lens 1 protrudes in the Z direction. Figure 20 is a half cross-sectional view of a vibration device 10C according to a modified example of embodiment 3. In the vibration device 10C shown in Figure 20, the same components as those in the vibration device 10 shown in Figure 2 are designated by the same reference numerals, and detailed description thereof will not be repeated.

[0066] 2, the vibration device 10C has an outermost lens 1 that protrudes in the Z direction and has a cylindrical shape. Specifically, in the vibration device 10C, the leaf spring 2a that extends in the X direction is bent in the Z direction near the vibration body 3, and the connection part 31 of the vibration body 3 and the retainer 2b are connected, so that the outermost lens 1 has a cylindrical shape that protrudes in the Z direction. The cover part 7 is in contact with the retainer 2b with an intermediate member 71 sandwiched therebetween. As mentioned above, the intermediate member 71 has a thickness t of 0.4 mm or less and a contact area S with the cover part 7 of 60 mm. ２If the length in the Z direction where the intermediate member 71 and the cover portion 7 are in contact is 1.0 mm and the inner circumference of the cover portion 7 is 55 mm, the contact area S is 1.0×55=55 mm. ２ In addition, since there is no limitation on the thickness w (length in the Z direction) of the intermediate member 71, it can be provided long along the retainer 2b.

[0067] (Embodiment 4) In the vibration device 10a according to the seventh modification of embodiment 1, a structure has been described in which the cover portion 7 is provided on the vehicle body 90 and the cover portion 7 is connected to the housing 2. In the vibration device according to embodiment 4, the cover portion may be configured as part of the vehicle body. Fig. 21 is a half cross-sectional view of a vibration device 10D according to embodiment 4. In the vibration device 10D shown in Fig. 21, the same components as those in the vibration device 10 shown in Fig. 2 are designated by the same reference numerals and detailed description thereof will not be repeated.

[0068] In the vibration device 10D, as shown in FIG. 21 , a portion of the housing 2 to which the vibrations of the vibration device 10D are not propagated is connected to the vehicle body 91, and a portion of the vehicle body 91 contacts the leaf spring 2a and the retainer 2b via intermediate members 71 and 72. In other words, a portion of the vehicle body 91 functions as the cover portion 7 shown in FIG. 2 . Therefore, the vibration device 10D can be structured without a cover portion. Note that the vibration frequency of the vehicle body 91 when the vehicle is running is approximately 1 to 100 Hz, and even if vibrations are transmitted to the vibration device 10D via the portion of the vehicle body 91 that functions as a cover portion, this frequency is significantly different from the resonant frequency of the vibration device 10D and does not affect the vibration performance.

[0069] (Embodiment 5) In the vibration device 10 according to embodiment 1, a structure in which a cover portion 7 is provided so as to cover the leaf spring 2a has been described. In embodiment 5, a method for fixing the cover portion to the housing will be described in detail. Fig. 22 is a perspective view of a vibration device 10E according to embodiment 5. In the vibration device 10E shown in Fig. 22, the same components as those in the vibration device 10 shown in Fig. 1 are designated by the same reference numerals, and detailed description thereof will not be repeated.

[0070] In the vibration device 10E, a cover portion 701 is attached to the housing 2 as shown in FIG. 22( a). The cover portion 701 has claw portions 701a provided at two opposing corners. Meanwhile, the housing 2 has stopper portions 201 provided at positions corresponding to the claw portions 701a. Therefore, the cover portion 701 can be attached to the housing 2 by fitting the claw portions 701a into the stopper portions 201. Note that, in the vibration device 10E, the number and positions of the claw portions 701a provided on the cover portion 701 are not limited to those shown in FIG. 22( a). The number and positions of the stopper portions 201 provided on the housing 2 correspond to the number and positions of the claw portions 701a provided on the cover portion 701.

[0071] Furthermore, Figure 22(b) illustrates a cover part 702 that is provided with press-fit protrusions 702a instead of claws. The cover part 702 has protrusions 702a at its four corners. Although not shown, the housing 2 has insertion parts at positions corresponding to the protrusions 702a. Note that the number and positions of the protrusions 702a provided on the cover part 702 are not limited to those shown in Figure 22(b). The number and positions of the insertion parts provided on the housing 2 correspond to the number and positions of the protrusions 702a provided on the cover part 702.

[0072] As a method for attaching the cover to the housing (a method for fixing the cover to the vibration device), mechanical fixing methods such as screws can be used in addition to the claws 701a, stopper 201, and press-fit protrusions 702a as described above. Also, a fixing method using an adhesive can be used as a method for attaching the cover to the housing.

[0073] (Other Modifications) The configurations described in the vibration device according to the above-described embodiment and the vibration device according to the above-described modification can be combined as appropriate. For example, the cover portion 7f of the second embodiment may be held by the vehicle body 90 described in FIG. 13 .

[0074] In the vibrating device according to the above embodiment, the cross-sectional shape of the support portion 33 is described as being S-shaped, but the cross-sectional shape of the support portion is not limited to S-shape as long as it is a shape that does not cause stress concentration in the vibrating body. The cross-sectional shape of the support portion 33 may be, for example, a shape formed by connecting multiple S-shapes, a curved shape that is half an S-shape, or the like.

[0075] The imaging device according to the above-described embodiment may include a camera, LiDAR, radar, etc. Also, a plurality of imaging devices may be arranged side by side.

[0076] 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.

[0077] (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, an extension portion that extends outward from a side wall of the vibrating body, which is a cylindrical body, and a cover portion that covers at least a portion of the extension portion and the vibrating body.

[0078] As a result, the vibration device according to the present disclosure does not degrade vibration performance by providing a cover portion that makes it difficult for foreign matter to adhere to at least a portion of the extension portion and the vibrating body.

[0079] (2) In the vibration device described in (1), the cover portion has a gap between the vibrating body and the extension portion where the displacement due to vibration of the vibrating body is greater than a predetermined value, and is held at the portion below the predetermined value.

[0080] (3) The vibration device according to (2) further comprises an intermediate member disposed in a gap between the vibrating body or the extension portion and the cover portion, the intermediate member having a Young's modulus of 1 GPa or less.

[0081] (4) The vibration device according to (2) further comprises an intermediate member disposed in the gap between the vibrating body or the extension and the cover, the intermediate member having a length of 0.4 mm or less in the extension direction of the extension.

[0082] (5) In the vibrating device according to (2), the contact area with the cover is 60 mm ２ The following intermediate members are further provided.

[0083] (6) In the vibration device described in (2), the cover portion is inclined from the light-transmitting body side toward the side where it is held, and the position of the held cover portion is lower than the position of the light-transmitting body in the axial direction of the cylindrical body.

[0084] (7) In the vibrating device according to (2) or (6), the cover has a guide portion that has an uneven surface facing the vibrating body or the extension portion and that discharges foreign matter.

[0085] (8) In the vibrating device according to (6) or (7), the cover has a surface facing the vibrating body or the extension portion coated with a water-repellent or hydrophilic coating material.

[0086] (9) In the vibrating device according to any one of (1) to (8), the cover is held by a part of the device to which the vibrating device is attached.

[0087] (10) In the vibration device according to any one of (1) to (8), the cover is a part of a device to which the vibration device is attached.

[0088] (11) In the vibrating device according to any one of (1) to (10), the cover is attached to the vibrating device by a mechanical fixing method or a fixing method using an adhesive.

[0089] (12) In the vibrating device described in (1), the cover part is in contact with at least the vibrating body and the portion of the extension part where the displacement due to vibration of the vibrating body is greater than a predetermined value, and is made of a material having a Young's modulus of 1 GPa or less.

[0090] (13) An imaging device according to the present disclosure includes the vibration device according to any one of (1) to (12) above, and an imaging element arranged such that the light-transmitting body is in the field of view.

[0091] 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.

[0092] REFERENCE SIGNS LIST 1 Outermost lens, 2 Housing, 2a Leaf spring, 2b Retainer, 3 Vibrating body, 5 Piezoelectric element, 6 Imaging element, 8 Bracket, 10 Vibrating device, 20 Sensor device, 31 Connection portion, 32 Vibrating portion, 33 Support portion, 71, 71a, 72, 72a Intermediate member, 73 Discharge hole, 74 Guide portion, 90 Vehicle body, 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; an extension portion that extends outward from a side wall of the vibrating body which is a cylindrical body; and a cover portion that covers at least a portion of the extension portion and the vibrating body.

2. The vibration device according to claim 1, wherein the cover portion has a gap between the vibrating body and the extension portion where the displacement due to vibration of the vibrating body is greater than a predetermined value, and is supported by the portion below the predetermined value.

3. The vibration device according to claim 2, further comprising an intermediate member having a Young's modulus of 1 GPa or less, provided in a gap between said vibrating body or said extension portion and said cover portion.

4. The vibration device according to claim 2, further comprising an intermediate member disposed in a gap between said vibrating body or said extension portion and said cover portion, said intermediate member having a length of 0.4 mm or less in the extension direction of said extension portion.

5. A contact area between the vibrator or the extension and the cover is 60 mm ２ The vibration device of claim 2 further comprising an intermediate member:

6. The vibration device according to claim 2, wherein the cover portion is inclined from the side of the translucent body toward the side where it is held, and the position of the held cover portion is lower than the position of the translucent body in the axial direction of the cylindrical body.

7. A vibration device as claimed in claim 2 or claim 6, wherein the cover portion has an uneven surface facing the vibrating body or the extension portion, and has a guide portion for discharging foreign matter.

8. The vibration device according to claim 6 or 7, wherein the cover portion has a surface facing the vibrating body or the extension portion coated with a water-repellent or hydrophilic coating material.

9. A vibration device according to any one of claims 1 to 8, wherein the cover portion is held by a part of a device to which the vibration device is attached.

10. A vibration device according to any one of claims 1 to 8, wherein the cover portion is part of a device to which the vibration device is attached.

11. The vibration device according to any one of claims 1 to 10, wherein the cover portion is attached to the vibration device by a mechanical fixing method or a fixing method using an adhesive.

12. The vibration device according to claim 1, wherein the cover portion is in contact with at least a portion of the vibrating body and the extension portion where the displacement caused by vibration of the vibrating body is greater than a predetermined value, and is formed from a material having a Young's modulus of 1 GPa or less.

13. An imaging device comprising: the vibration device according to any one of claims 1 to 12; and an imaging element arranged so that the light-transmitting body is in the field of view.

Images