Optical Module and Optical Device

Abstract

This optical module comprises: a transparent body; a vibrating body that is formed in a tubular shape, and that supports the transparent body; a piezoelectric element that is disposed on the vibrating body, and that vibrates the vibrating body; and an inner layer optical component disposed in the vibrating body. The inner layer optical component includes an inner layer lens that opposes the transparent body. The surface of the inner layer lens opposing the transparent body has a first recess that is formed in the thickness direction of the inner layer lens and that has a curvature. A gap is formed between the transparent body and the first recess of the inner layer lens.

Description

Technical Field

[0001] The present invention relates to an optical module and an optical device for removing droplets or the like by vibration.

Background Art

[0002] Patent Document 1 discloses a droplet elimination device including a vibration member that is connected to an end of a curved surface forming a dome portion of an optical element and generates bending vibration in the dome portion. In the droplet elimination device described in Patent Document 1, a drip-proof cover and a piezoelectric element are adhesively fixed, and the drip-proof cover is bent and vibrated by the vibration of the piezoelectric element to remove droplets or the like adhering to the surface of the drip-proof cover.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the device described in Patent Document 1, there is still room for improvement in terms of suppressing vibration attenuation.

Means for Solving the Problems

[0005] An optical module according to one aspect of the present invention includes a light-transmitting body, a vibrating body formed in a cylindrical shape and supporting the light-transmitting body, a piezoelectric element disposed on the vibrating body and vibrating the vibrating body, an inner layer optical component disposed inside the vibrating body, and the inner layer optical component includes an inner layer lens facing the light-transmitting body, on a surface of the inner layer lens facing the light-transmitting body, a first concave portion that is recessed in the thickness direction of the inner layer lens and has a curvature is formed. A gap is formed between the light-transmitting body and the first concave portion of the inner layer lens.

[0006] An optical device according to one aspect of the present invention includes the optical module of the above aspect, and an optical element disposed in the optical module.

Advantages of the Invention

[0007] According to the present invention, it is possible to provide an optical module and an optical device capable of suppressing vibration attenuation.

Brief Description of the Drawings

[0008]

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Mode for Carrying Out the Invention

[0009] (Background Leading to the Present Invention) In a vehicle provided with an imaging unit having an imaging element or the like at the front or rear of the vehicle, a safety device is controlled or automatic driving control is performed using the image acquired by the imaging unit. Such an imaging unit may be disposed outside the vehicle. In this case, a light-transmitting body such as a protective cover or a lens is disposed on the exterior of the imaging unit.

[0010] For this reason, foreign matters such as raindrops (droplets), mud, and dust may adhere to the light-transmitting body. When foreign matters adhere to the light-transmitting body, the foreign matters may be reflected in the image acquired by the imaging unit, and a clear image may not be obtained.

[0011] In recent years, a device for removing foreign matters adhering to a light-transmitting body by vibrating the light-transmitting body has been developed. In such a device, the light-transmitting body is disposed in a cylindrical vibrating body, and the light-transmitting body is vibrated by vibrating the vibrating body with a piezoelectric element or the like. Further, inner layer optical components such as an inner layer lens are disposed inside the vibrating body.

[0012] However, depending on the position of the inner layer optical component disposed inside the vibrating body, the vibration of the light-transmitting body and / or the vibrating body may be attenuated. For example, a gap is provided between the light-transmitting body and the inner layer optical component, and vibration attenuation may occur depending on the dimension of the gap. As a result, there is a problem that foreign matters adhering to the light-transmitting body cannot be sufficiently removed. This is a new problem discovered by the inventors.

[0013] For example, when a translucent body is vibrated, sound waves are generated by the vibration. The sound waves generated from the translucent body are reflected by the inner layer optical component, and a standing wave including antinodes and nodes of the sound waves is generated. At the antinode of the sound wave, the sound pressure rises compared to other parts, and the air is in a more compressed state. Therefore, at the antinode of the sound wave, the compressed air acts as a damper, and vibration attenuation occurs. Thus, when an antinode of the sound wave is formed at the position where the translucent body is disposed in the gap between the translucent body and the inner layer optical component, the vibration of the translucent body is attenuated. As a result, foreign matter attached to the translucent body may not be sufficiently removed.

[0014] Also, in order to avoid the antinodes generated by the reflection of the sound waves generated from the translucent body and dispose the inner layer optical component, it has been considered to dispose the inner layer optical component closer to the translucent body and reduce the gap between the translucent body and the inner layer optical component. In this case, regardless of the presence or absence of the standing wave, the volume of air in the gap becomes small and the sound pressure rises. As a result, vibration attenuation may occur.

[0015] As a result of intensive studies, the inventors of the present invention have found a configuration for suppressing vibration attenuation by suppressing an increase in sound pressure in the gap between the translucent body and the inner layer optical component, and have reached the following invention.

[0016] An optical module according to an aspect of the present invention includes a translucent body, a vibrating body formed in a cylindrical shape that supports the translucent body, a piezoelectric element disposed on the vibrating body that vibrates the vibrating body, and an inner layer optical component disposed inside the vibrating body. The inner layer optical component includes an inner layer lens facing the translucent body, and a first concave portion that is recessed in the thickness direction of the inner layer lens and has a curvature is formed on the surface of the inner layer lens facing the translucent body. A gap is formed between the translucent body and the first concave portion of the inner layer lens.

[0017] With such a configuration, vibration attenuation can be suppressed.

[0018] When viewed from the thickness direction of the translucent body, the first concave portion may be formed at a position overlapping the central portion of the translucent body.

[0019] With such a configuration, it is possible to suppress vibration attenuation in the central portion of the light-transmitting body.

[0020] When viewed from the thickness direction of the light-transmitting body, the center of the first concave portion may substantially coincide with the center of the light-transmitting body.

[0021] With such a configuration, it is possible to further suppress vibration attenuation in the central portion of the light-transmitting body.

[0022] The depth of the first concave portion may decrease toward the outside from the center of the inner layer lens when viewed from the thickness direction of the inner layer lens.

[0023] With such a configuration, when the sound wave generated by the vibration of the light-transmitting body is reflected by the first concave portion, it is likely to be dispersed, and vibration attenuation of the light-transmitting body can be suppressed.

[0024] The first concave portion may be formed in a spherical shape or an aspherical shape.

[0025] With such a configuration, the sound wave generated by the vibration of the light-transmitting body is more likely to be dispersed, and vibration attenuation of the light-transmitting body can be further suppressed.

[0026] On the surface of the light-transmitting body facing the inner layer lens, a second concave portion that is recessed in the thickness direction of the light-transmitting body and has a curvature may be formed.

[0027] With such a configuration, the sound wave is likely to be dispersed by the second concave portion, and vibration attenuation of the light-transmitting body can be suppressed.

[0028] The second concave portion of the light-transmitting body may have a shape that is recessed in a hemispherical shape.

[0029] With such a configuration, the sound wave is more likely to be dispersed by the second concave portion, and vibration attenuation of the light-transmitting body can be further suppressed.

[0030] When viewed from the thickness direction of the light-transmitting body, the outer diameter of the inner layer lens may be larger than the outer diameter of the second concave portion of the light-transmitting body.

[0031] With such a configuration, while improving optical characteristics, vibration attenuation of the light-transmitting body can be suppressed.

[0032] The curvature of the first concave portion of the inner layer lens may be larger than the curvature of the second concave portion of the light-transmitting body.

[0033] With such a configuration, while securing an optical path passing through the inner layer lens from the light-transmitting body, vibration attenuation of the light-transmitting body can be suppressed.

[0034] The maximum dimension of the gap may be 0.5 mm or more.

[0035] With such a configuration, vibration attenuation of the light-transmitting body can be further suppressed.

[0036] The maximum dimension of the gap may be defined in the range of [(n×λ / 2)+0.1 mm] or more and [{(n + 1)×λ / 2}-0.1 mm] or less, where n is an integer of 0 or more, and λ represents the wavelength of the sound wave generated by vibration.

[0037] With such a configuration, vibration attenuation of the light-transmitting body can be further suppressed.

[0038] The maximum dimension of the gap may be the dimension between the light-transmitting body and the first concave portion on a straight line passing through the center of the light-transmitting body and the center of the first concave portion when viewed from the thickness direction of the light-transmitting body.

[0039] With such a configuration, vibration attenuation at the center of the light-transmitting body can be suppressed.

[0040] The inner layer lens has a flat surface orthogonal to the thickness direction of the inner layer lens on the surface facing the light transmissive body, and the inner layer optical component includes a cylindrical lens holding portion for housing the inner layer lens, and the lens holding portion may have a pressing portion that contacts the flat surface inside the lens holding portion.

[0041] With such a configuration, it is possible to hold the inner layer lens while maintaining its optical characteristics.

[0042] An optical device according to one aspect of the present invention includes the optical module according to the above aspect and an optical element disposed in the optical module.

[0043] With such a configuration, vibration attenuation can be suppressed.

[0044] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. Note that the following description is merely illustrative in nature and is not intended to limit the present disclosure, its applications, or its uses. Further, the drawings are schematic, and the ratios of the respective dimensions do not necessarily match the actual ones.

[0045] (Embodiment 1) [Optical Device] FIG. 1 is a schematic perspective view showing an example of an optical device 100 according to Embodiment 1 of the present invention. FIG. 2 is a schematic cross-sectional view showing an example of the configuration of the optical device 100 according to Embodiment 1 of the present invention. The X, Y, and Z directions in the figures indicate the longitudinal direction, the lateral direction, and the height direction of the optical device 100, respectively.

[0046] As shown in FIGS. 1 and 2, the optical device 100 includes an optical module 1 and an optical element 2. The optical element 2 is disposed in the optical module 1. Specifically, the optical element 2 is disposed inside the optical module 1.

[0047] In this embodiment, an example where the optical device 100 is an imaging device will be described. The optical device 100 is attached, for example, to the front or rear of a vehicle and images an imaging target. Note that the location where the optical device 100 is attached is not limited to a vehicle and may be attached to other devices such as ships and aircraft.

[0048] The optical element 2 is an imaging element, and is, for example, a CMOS, a CCD, a bolometer, or a thermopile that receives light having a wavelength in any of the visible region to the far-infrared region.

[0049] When the optical device 100 is attached to a vehicle or the like and used outdoors, foreign matters such as raindrops, mud, and dust may adhere to the light-transmitting body 10 of the optical module 1 disposed in the viewing direction of the optical element 2 and covering the outside. The optical module 1 can generate vibration to remove foreign matters such as raindrops adhering to the light-transmitting body 10.

[0050] [Optical module] As shown in FIGS. 1 and 2, the optical module 1 includes a light-transmitting body 10, a vibrating body 20, a piezoelectric element 30, a fixing portion 40, and an inner-layer optical component 50. Note that in the optical module 1, the fixing portion 40 is not an essential configuration.

[0051] [Light-transmitting body] The light-transmitting body 10 has light-transmitting properties through which energy rays or light having wavelengths detected by the optical element 2 can pass. In this embodiment, the light-transmitting body 10 is a cover for protecting the optical element 2 and the inner-layer optical component 50 from the adhesion of foreign matters. In the optical device 100, the optical element 2 detects energy rays or light through the light-transmitting body 10.

[0052] As the material for forming the light-transmitting body 10, for example, light-transmitting plastics, glass such as quartz and borosilicate, light-transmitting ceramics, or synthetic resins can be used. By forming the light-transmitting body 10 with, for example, tempered glass, it is possible to increase the strength of the light-transmitting body 10. In this embodiment, the light-transmitting body 10 is formed of BK-7 (borosilicate glass).

[0053] The light-transmitting body 10 has, for example, a dome shape. When viewed from the height direction (Z direction) of the optical module 1, the light-transmitting body 10 is formed in a circular shape. Note that the shape of the light-transmitting body 10 is not limited to this.

[0054] In the present embodiment, the light-transmitting body 10 has a first main surface PS1 and a second main surface PS2 on the side opposite to the first main surface PS1. The first main surface PS1 is the main surface located on the outer side of the light-transmitting body 10. The first main surface PS1 is formed as a continuous curved surface. Specifically, the first main surface PS1 is curved in a round shape. The second main surface PS2 is the main surface located on the inner side of the light-transmitting body 10. A concave portion 11 is provided in the second main surface PS2 as a flat surface. In this specification, the concave portion 11 may be referred to as the second concave portion.

[0055] Specifically, the second main surface PS2 is the surface of the light-transmitting body 10 that faces the inner layer optical component 50. A concave portion 11 that is recessed in the thickness direction (Z direction) of the light-transmitting body 10 and has a curvature is formed in the second main surface PS2. For example, the concave portion 11 is provided at the center of the light-transmitting body 10 when viewed from the thickness direction (Z direction) of the light-transmitting body 10 and has a circular shape. For example, the concave portion 11 has a shape that is recessed in a hemispherical shape.

[0056] The outer peripheral end portion of the light-transmitting body 10 is joined to the vibrating body 20. Specifically, the second main surface PS2 of the light-transmitting body 10 and the vibration flange 21 of the vibrating body 20 are joined along the outer periphery of the light-transmitting body 10 when viewed from the thickness direction (Z direction) of the light-transmitting body 10. The joining of the light-transmitting body 10 and the vibrating body 20 can be performed using, for example, an adhesive or a brazing material. Alternatively, thermocompression bonding or anodic bonding can also be used.

[0057] <Vibrating body> The vibrating body 20 is formed in a cylindrical shape and supports the light-transmitting body 10. Further, the vibrating body 20 vibrates the light-transmitting body 10 by being vibrated by the piezoelectric element 30.

[0058] The vibrating body 20 has a vibration flange 21, a first cylindrical body 22, a spring portion 23, a second cylindrical body 24, a diaphragm 25, and a connection portion 26. In the vibrating body 20, the connection portion 26 is not an essential component.

[0059] The vibration flange 21 is formed of an annular plate member when viewed from the height direction (Z direction) of the optical module 1. The vibration flange 21 is arranged along the outer periphery of the light transmissive body 10 and joined to the light transmissive body 10. The vibration flange 21 stably supports the light transmissive body 10 by being in surface contact with the light transmissive body 10.

[0060] The first cylindrical body 22 is formed in a cylindrical shape having one end and the other end. The first cylindrical body 22 is a hollow member provided with a through hole inside. The through hole is provided in the height direction (Z direction) of the optical module 1, and openings of the through hole are provided at one end and the other end of the first cylindrical body 22. The first cylindrical body 22 has, for example, a cylindrical shape. When viewed from the height direction of the optical module 1, the outer shape of the first cylindrical body 22 and the openings of the through hole are formed in a circular shape.

[0061] The vibration flange 21 is provided at one end of the first cylindrical body 22, and the spring portion 23 is provided at the other end of the first cylindrical body 22. The first cylindrical body 22 supports the vibration flange 21 while being supported by the spring portion 23.

[0062] The spring portion 23 is a leaf spring that supports the other end of the first cylindrical body 22. The spring portion 23 is configured to elastically deform. The spring portion 23 supports the other end of the cylindrical first cylindrical body 22 and extends outward from the supported position toward the outside of the first cylindrical body 22.

[0063] The spring portion 23 is formed in a plate shape. Further, the spring portion 23 has a hollow circular shape provided with a through hole inside and extends so as to surround the first cylindrical body 22 in a circular shape. In other words, the spring portion 23 has an annular plate shape. The annular plate shape means a shape in which a plate member is formed in an annular shape. When viewed from the height direction (Z direction) of the optical module 1, the outer shape of the spring portion 23 and the openings of the through hole are formed in a circular shape.

[0064] The spring portion 23 connects the first cylindrical body 22 and the second cylindrical body 24. Specifically, the spring portion 23 is connected to the first cylindrical body 22 on the inner peripheral side of the spring portion 23, and is connected to the second cylindrical body 24 on the outer peripheral side of the spring portion 23.

[0065] The second cylindrical body 24 is formed in a cylindrical shape having one end and the other end. The second cylindrical body 24 is located outside the first cylindrical body 22 when viewed from the height direction (Z direction) of the optical module 1, and supports the spring portion 23. One end of the second cylindrical body 24 is connected to the spring portion 23. A diaphragm 25 is connected to the other end of the second cylindrical body 24.

[0066] The second cylindrical body 24 is composed of a hollow member provided with a through hole inside. The through hole is provided in the height direction (Z direction) of the optical module 1, and openings of the through hole are provided at one end and the other end of the second cylindrical body 24. The second cylindrical body 24 has, for example, a cylindrical shape. When viewed from the height direction of the optical module 1, the outer shape of the second cylindrical body 24 and the opening of the through hole are formed in a circular shape.

[0067] The diaphragm 25 is a plate-like member extending inward from the other end of the second cylindrical body 24. The diaphragm 25 supports the other end of the second cylindrical body 24 and extends from the supported position toward the inside of the second cylindrical body 24.

[0068] The diaphragm 25 has a hollow circular shape provided with a through hole inside, and is provided along the inner circumference of the second cylindrical body 24. The diaphragm 25 has an annular plate shape.

[0069] The connecting portion 26 connects the diaphragm 25 and the fixing portion 40. The connecting portion 26 extends outward from the outer peripheral end portion of the diaphragm 25 and bends toward the fixing portion 40. The connecting portion 26 is supported by the fixing portion 40. The connecting portion 26 is configured to have a node, and it is difficult for the vibration from the diaphragm 25 to be transmitted.

[0070] In this embodiment, the first cylindrical body 22, the spring portion 23, the second cylindrical body 24, the diaphragm 25, and the connecting portion 26 are integrally formed. Note that the first cylindrical body 22, the spring portion 23, the second cylindrical body 24, the diaphragm 25, and the connecting portion 26 may be formed separately or formed of separate members.

[0071] The elements constituting the vibrating body 20 described above are formed of, for example, metal or ceramics. As the metal, for example, stainless steel, 42 alloy, 50 alloy, invar, super invar, kovar, aluminum, or duralumin, etc. can be used. Alternatively, the elements constituting the vibrating body 20 may be formed of ceramics such as alumina or zirconia, or may be formed of a semiconductor such as Si. Furthermore, the elements constituting the vibrating body 20 may be covered with an insulating material. Also, the elements constituting the vibrating body 20 may be subjected to black body treatment.

[0072] Also, the shape and arrangement of the elements constituting the vibrating body 20 are not limited to the above examples.

[0073] <Piezoelectric element> The piezoelectric element 30 is disposed on the vibrating body 20 and vibrates the vibrating body 20. The piezoelectric element 30 is provided on the main surface of the diaphragm 25. Specifically, the piezoelectric element 30 is provided on the main surface of the diaphragm 25 on the side opposite to the side where the light-transmitting body 10 is located. The piezoelectric element 30 vibrates the second cylindrical body 24 in the penetrating direction (Z direction) by vibrating the diaphragm 25. For example, the piezoelectric element 30 vibrates when a voltage is applied.

[0074] The piezoelectric element 30 has a hollow circular shape with a through hole provided inside. In other words, the piezoelectric element 30 has an annular plate shape. When viewed from the height direction (Z direction) of the optical module 1, the outer shape of the piezoelectric element 30 and the opening of the through hole are formed in a circular shape.

[0075] Note that the outer shape of the piezoelectric element 30 and the opening of the through hole are not limited thereto.

[0076] The piezoelectric element 30 has a piezoelectric body and electrodes. As a material for forming the piezoelectric body, for example, barium titanate (BaTiO3), lead titanate zirconate (PZT: PbTiO3·PbZrO3), lead titanate (PbTiO3), lead metaniobate (PbNb2O6), bismuth titanate (Bi4Ti3O 12 )), appropriate piezoelectric ceramics such as (K,Na)NbO3, or appropriate piezoelectric single crystals such as LiTaO3, LiNbO3, etc. can be used. The electrode may be, for example, a Ni electrode. The electrode may be an electrode made of a metal thin film such as Ag or Au formed by a sputtering method. Alternatively, the electrode can be formed not only by sputtering but also by plating or vapor deposition.

[0077] The fixing part 40 fixes the vibrating body 20. Also, the fixing part 40 fixes the inner layer optical component 50. The fixing part 40 is formed in a cylindrical shape. For example, the fixing part 40 has a cylindrical shape. Note that the shape of the fixing part 40 is not limited to a cylindrical shape. The fixing part 40 may be integrally formed with the vibrating body 20.

[0078] <Inner layer optical component> As shown in FIG. 2, the inner layer optical component 50 is an optical component disposed inside the vibrating body 20. For example, the inner layer optical component 50 is a lens module.

[0079] In this embodiment, the inner layer optical component 50 has an inner layer lens 51, a lens holding part 52, and an inner layer flange 53.

[0080] The inner layer lens 51 is composed of a plurality of lenses. The inner layer lens 51 is disposed on the optical path of the optical element 2 inside the vibrating body 20 and faces the light transmissive body 10. A concave portion 51a is formed on the surface of the inner layer lens 51 that faces the light transmissive body 10. Specifically, among the plurality of lenses constituting the inner layer lens 51, the concave portion 51a is formed on the surface of the lens disposed at the position facing the light transmissive body 10. In this specification, the concave portion 51a may be referred to as the first concave portion 51a.

[0081] The first recess 51a is formed such that it is recessed in the thickness direction (Z direction) of the inner lens 51 and has a curvature on the surface of the inner lens 51 facing the light-transmitting body 10. The first recess 51a is recessed in a direction away from the light-transmitting body 10.

[0082] The depth of the first recess 51a decreases toward the outside from the center of the inner lens 51 when viewed in the thickness direction of the inner lens 51. Also, the first recess 51a has a circular shape when viewed in the thickness direction (Z direction) of the inner lens 51. For example, the first recess 51a is formed in a spherical shape or an aspherical shape.

[0083] In the present embodiment, the first recess 51a is formed in a spherical shape. Specifically, the first recess 51a is formed by being recessed hemispherically in the thickness direction of the inner lens 51 on the surface of the inner lens 51 facing the light-transmitting body 10. When viewed in the thickness direction (Z direction) of the inner lens 51, the first recess 51a is formed at the center of the inner lens 51. Also, when viewed in the thickness direction of the inner lens 51, a flat surface FS1 is formed on the outer periphery of the first recess 51a. The flat surface FS1 extends in a direction orthogonal to the thickness direction (Z direction) of the inner lens 51.

[0084] The inner lens 51 is constituted by, for example, a spherical lens. Note that the inner lens 51 is not limited to a spherical lens and may be constituted by an aspherical lens.

[0085] The lens holding portion 52 holds the inner lens 51. The lens holding portion 52 is formed in a cylindrical shape having one end and the other end. Specifically, the lens holding portion 52 has a cylindrical shape and holds the outer periphery of the inner lens 51.

[0086] The lens holding portion 52 has a pressing portion 52a that contacts the flat surface FS1 of the inner layer lens 51 inside the lens holding portion 52. The pressing portion 52a is a member that protrudes inside the lens holding portion 52 at one end of the lens holding portion 52. The pressing portion 52a is formed in an annular shape when viewed from the height direction (Z direction) of the inner layer optical component 50. The pressing portion 52a contacts the flat surface FS1 of the inner layer lens 51 and presses the flat surface FS1 in the thickness direction (Z direction) of the inner layer lens 51.

[0087] In the present embodiment, at the other end of the lens holding portion 52, a contact portion 52b that contacts the inner layer lens 51 is provided. The contact portion 52b protrudes inside the lens holding portion 52 on the other end side of the lens holding portion 52. For example, the contact portion 52b is formed in an annular shape when viewed from the height direction (Z direction) of the inner layer optical component 50. The inner layer lens 51 is housed in the lens holding portion 52 and is pressed against the contact portion 52b by the pressing portion 52a. Thereby, the inner layer lens 51 is held in the lens holding portion 52. Note that the contact portion 52b may be detachable from the lens holding portion 52. For example, the contact portion 52b may have an annular shape and may be attached to the lens holding portion 52 by a screw structure.

[0088] The inner layer flange 53 extends outward from the outer wall of the lens holding portion 52. Specifically, the inner layer flange 53 is connected to the other end of the lens holding portion 52 and extends toward the fixing portion 40. The inner layer flange 53 is formed in an annular plate shape when viewed from the height direction (Z direction) of the optical module 1. The outer periphery of the inner layer flange 53 is connected to the fixing portion 40. The inner layer flange 53 is fixed inside the vibrating body 20 by being supported by the fixing portion 40.

[0089] FIG. 3 is a block diagram showing an example of the functional configuration of the optical device 100 according to Embodiment 1 of the present invention. As shown in FIG. 3, the piezoelectric element 30 is controlled by the control unit 3. The control unit 3 applies a drive signal for generating vibration to the piezoelectric element 30. The control unit 3 is connected to the piezoelectric element 30 via, for example, a power supply conductor. The piezoelectric element 30 vibrates in the height direction (Z direction) of the optical module 1 based on the drive signal from the control unit 3. When the piezoelectric element 30 vibrates, the vibrating body 20 is vibrated, and the vibration of the vibrating body 20 is transmitted to the light-transmitting body 10, causing the light-transmitting body 10 to vibrate. Thereby, foreign matters such as raindrops attached to the light-transmitting body 10 are removed.

[0090] The control unit 3 can be realized by, for example, a semiconductor element or the like. For example, the control unit 3 can be composed of a microcomputer, a CPU (Central Processing Unit), an MPU (Micro Processing Unit), a GPU (Graphics Processing Unit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), or an ASIC (Application Specific Integrated Circuit). The functions of the control unit 3 may be configured by hardware only, or may be realized by combining hardware and software.

[0091] For example, the control unit 3 reads data and programs stored in the storage unit and performs various arithmetic processes to realize a predetermined function.

[0092] The control unit 3 may be included in the optical device 100, or may be included in a control device separate from the optical device 100. For example, when the control unit 3 is not included in the optical device 100, the optical device 100 may be controlled by a control device including the control unit 3. Alternatively, the control unit 3 may be included in the optical module 1.

[0093] [Regarding the gap] Next, in the optical module 1, the gap formed between the light-transmitting body 10 and the inner layer lens 51 will be described.

[0094] Returning to FIG. 2, a gap G0 is formed between the light-transmitting body 10 and the inner layer lens 51.

[0095] FIG. 4 is a schematic diagram for explaining the gap G0 between the light-transmitting body 10 and the inner layer lens 51. FIG. 4(a) shows a schematic view of the light-transmitting body 10 as seen from the first main surface PS1 side, and FIG. 4(b) shows a schematic cross-sectional view near the light-transmitting body 10. In FIG. 4, reference numeral D11 indicates the outer diameter of the light-transmitting body 10, reference numeral D12 indicates the outer diameter of the second recess 11 of the light-transmitting body 10, reference numeral D21 indicates the outer diameter of the first recess 51a of the inner layer lens 51, and reference numeral D22 indicates the outer diameter of the inner layer lens 51. Reference numeral A1 indicates the vibration direction of the light-transmitting body 10. Note that the outer diameter D12 of the second recess 11 means the diameter of the outer edge defining the second recess 11 on the second main surface PS2 of the light-transmitting body 10. The outer diameter D22 of the first recess 51a means the diameter of the outer edge defining the first recess 51a on the surface of the inner layer lens 51 facing the light-transmitting body 10. Further, D11, D12, D21, and D22 are dimensions when viewed from the height direction (Z direction) of the optical module 1, respectively.

[0096] In the present embodiment, when viewed from the height direction ( Z direction direction) of the optical module 1, the outer diameter D12 of the second recess 11 is larger than the outer diameter D22 of the first recess 51a of the inner layer lens 51. Also, the outer diameter D22 of the inner layer lens 51 is larger than the outer diameter D12 of the second recess 11. By making the outer diameter D22 of the inner layer lens 51 larger than the outer diameter D12 of the second recess 11, light incident from the light-transmitting body 10 is more likely to enter the optical element 2 through the inner layer lens 51. Thereby, the optical characteristics can be improved.

[0097] Further, the curvature of the first recess 51a of the inner layer lens 51 is larger than the curvature of the second recess 11 of the light-transmitting body 10. Thereby, it becomes easier to secure an optical path passing from the light-transmitting body 10 through the inner layer lens 51.

[0098] As shown in FIG. 4, the gap G0 is formed between the light-transmitting body 10 and the inner layer lens 51. Specifically, the gap G0 is formed between the second main surface PS2 of the light-transmitting body 10 and the surface of the inner layer lens 51 facing the second main surface PS2 of the light-transmitting body 10.

[0099] When viewed from the thickness direction (Z direction) of the light-transmitting body 10, the first recess 51a is formed at a position overlapping the central portion of the light-transmitting body 10. The central portion of the light-transmitting body 10 means the central portion of the light-transmitting body 10 when viewed from the first main surface PS1 side. For example, when viewed from the first main surface PS1 side of the light-transmitting body 10, the central portion of the light-transmitting body 10 is a circular region centered on the center C1 of the light-transmitting body 10. For example, the diameter of the central portion of the light-transmitting body 10 is 2 / 3 times or less of the outer diameter D1 of the light-transmitting body 10 when viewed from the first main surface PS1 side. Preferably, the diameter of the central portion may be 1 / 2 times or less of the outer diameter D1 of the light-transmitting body 10. Also, the diameter of the central portion may be 1 / 3 times or more of the outer diameter D1 of the light-transmitting body 10.

[0100] When viewed from the thickness direction (Z direction) of the light-transmitting body 10, the first recess 51a The center C2 of coincides substantially with the center C1 of the light-transmitting body 10. In this specification, "substantially coincide" may include an error of ±5% or less. In other words, the center line of the light-transmitting body 10 extending along the height direction (Z direction) of the optical module 1 passes through the center C1 of the light-transmitting body 10 and the center C2 of the inner layer lens 51.

[0101] When viewed from the thickness direction (Z direction) of the inner layer lens 51, the depth of the first recess 51a decreases outward from the center C2 of the inner layer lens 51. Also, when viewed from the thickness direction (Z direction) of the light-transmitting body 10, the depth of the second recess 11 decreases outward from the center C1 of the light-transmitting body 10. Note that the depth of the first recess 51a means the dimension in the thickness direction (Z direction) of the inner layer lens 51, and the depth of the second recess 11 means the dimension in the thickness direction (Z direction) of the light-transmitting body 10.

[0102] The gap G0 becomes smaller toward the outside from the center C1 of the light-transmitting body 10 and the center C2 of the inner layer lens 51. Specifically, the dimension of the gap G0 in the height direction (Z direction) of the optical module 1 becomes smaller toward the outside from the center C1 of the light-transmitting body 10 and the center C2 of the inner layer lens 51.

[0103] In the present embodiment, when viewed from the thickness direction (Z direction) of the light-transmitting body 10, the center C2 of the first recess 51a substantially coincides with the center C1 of the light-transmitting body 10. Therefore, in the gap G0, the dimension between the light-transmitting body 10 and the first recess 51a on the straight line passing through the center C1 of the light-transmitting body 10 and the center C2 of the first recess 51a when viewed from the thickness direction (Z direction) of the light-transmitting body 10 becomes the largest. In this specification, the dimension at which the gap G0 becomes the largest in the height direction (Z direction) of the optical module 1 is defined as "the maximum dimension L1 of the gap G0". The maximum dimension L1 of the gap G0 is preferably 0.5 mm or more.

[0104] In this way, by forming the first recess 51a on the surface of the inner layer lens 51 facing the light-transmitting body 10, the sound pressure generated in the gap G0 can be dispersed. Specifically, the sound wave generated in the gap G0 due to the vibration of the light-transmitting body 10 hits the first recess 51a and is reflected. Since the first recess 51a has a curvature, that is, a curved shape, the sound wave is reflected in various directions when it hits the first recess 51a. In this way, the sound wave reflected by the first recess 51a is dispersed, so that the concentration of the sound pressure in the gap G0 can be suppressed. Thereby, the occurrence of vibration attenuation can be suppressed.

[0105] [Regarding the relationship between the displacement amount of the light-transmitting body and the sound pressure] In order to examine the relationship between the displacement amount of the light-transmitting body 10 and the sound pressure, simulations were performed using the analysis models of Comparative Example 1 and Example 1. The analysis models and simulation results of Comparative Example 1 and Example 1 will be described with reference to FIGS. 5 to 7. The simulation was performed using Femtet manufactured by Murata Software Co., Ltd. for piezoelectric / ultrasonic wave analysis (harmonic analysis, strong coupling). In the analysis model, the material of the light-transmitting body 10 was borosilicate glass, the material forming the vibrating body 20 was stainless steel, and the piezoelectric element 30 was PZT. Further, the light-transmitting body 10 and the vibrating body 20 were adhered with an epoxy resin. The resonance frequency of the vibrating body 20 was set to 27 kHz.

[0106] FIG. 5 is a schematic diagram for explaining Comparative Example 1 and Example 1. As shown in FIG. 5, in Comparative Example 1, an analysis model having an inner layer lens whose entire surface facing the light-transmitting body is a flat surface is used. In Comparative Example 1, the first recess is not formed in the inner layer lens. In Example 1, an analysis model having the configuration of the optical module 1 described in the present embodiment is used. In Example 1, the only difference from Comparative Example 1 is that the first recess 51a is provided in the inner layer lens 51, but the other configurations are the same.

[0107] FIG. 6 is a graph for explaining an example of the simulation results of the displacement amount and sound pressure of the light-transmitting body in Comparative Example 1 and Example 1. The sound pressure shown in FIG. 6 indicates the sound pressure in the gap G0, and the displacement amount indicates the displacement amount of the central portion of the light-transmitting body 10.

[0108] As shown in FIG. 6, in Example 1, compared with Comparative Example 1, the sound pressure in the gap G0 is reduced and the displacement amount of the light-transmitting body 10 is increased. In Example 1, since the first recess 51a is provided on the surface of the inner layer lens 51 facing the light-transmitting body 10, when the sound wave generated by the vibration of the light-transmitting body 10 is reflected by the first recess 51a in the gap G0, it is more likely to be dispersed than in Comparative Example 1. For this reason, in Example 1, it is possible to suppress the concentration of sound waves at the center of the gap G0. Thereby, in Example 1, compared with Comparative Example 1, the sound pressure in the gap G0 can be reduced and vibration attenuation can be suppressed.

[0109] On the other hand, in Comparative Example 1, since the first concave portion is not formed on the surface of the inner layer lens facing the light-transmitting body and the entire surface is formed flat, the sound waves reflected by the inner layer lens are less likely to be dispersed. Therefore, in Comparative Example 1, compared with Example 1, the sound waves are more likely to concentrate, and the sound pressure is likely to increase. For this reason, in Comparative Example 1, vibration attenuation cannot be suppressed compared with Example 1, and the displacement amount is small. in For this reason, in Comparative Example 1, vibration attenuation cannot be suppressed compared with Example 1, and the displacement amount is small.

[0110] As described above, in Example 1, compared with Comparative Example 1, the sound waves are likely to be dispersed in the gap G0, and the sound pressure in the gap G0 can be reduced. As a result, in Example 1, compared with Comparative Example 1, vibration attenuation can be suppressed, and the displacement amount of the light-transmitting body 10 can be increased.

[0111] FIG. 7 is a diagram for explaining an example of the displacement distribution and the sound pressure distribution in Comparative Example 1 and Example 1. As shown in FIG. 7, in Comparative Example 1, the maximum displacement amount of the light-transmitting body is about 6 μm, and in Example 1, the maximum displacement amount is about 8.0 μm.

[0112] On the other hand, focusing on the sound pressure distribution, it can be seen that in Example 1, the sound pressure in the gap G0 is smaller than that in Comparative Example 1. In particular, in Example 1, it can be seen that the sound pressure in the vicinity of the center of the gap G0, that is, the portion where the gap G0 is the largest, is smaller than that in Comparative Example 1. From this, it can be seen that in Example 1, compared with Comparative Example 1, the sound waves are dispersed in the gap G0, and the concentration of the sound waves is suppressed.

[0113] [Regarding the maximum dimension of the gap] FIG. 8 is a graph showing an example of the relationship between the maximum dimension of the gap and the displacement amount of the light-transmitting body. As shown in FIG. 8, as the maximum dimension L1 of the gap G0 increases, the displacement amount of the light-transmitting body 10 increases. The maximum dimension L1 of the gap G0 may be 0.5 mm or more. Preferably, the maximum dimension L1 of the gap G0 is 1.5 mm or more. More preferably, the maximum dimension L1 of the gap G0 is 2.25 mm or more.

[0114] When the displacement amount of the light-transmitting body 10 is less than 0.3 μm / V, it becomes difficult to remove foreign matters such as droplets adhering to the first main surface PS1 of the light-transmitting body 10. When the maximum dimension L1 of the gap G0 is 0.5 mm or more, the displacement amount of the light-transmitting body 10 becomes 0.3 μm / V or more, and it becomes easier to remove the foreign matters adhering to the first main surface PS1 of the light-transmitting body 10. Further, when the maximum dimension L1 of the gap G0 is 1.5 mm or more, the displacement amount of the light-transmitting body 10 becomes 0.35 μm / V or more, and it becomes even easier to remove the foreign matters adhering to the first main surface PS1 of the light-transmitting body 10. Furthermore, when the maximum dimension L1 of the gap G0 is 2.25 mm or more, the displacement amount of the light-transmitting body 10 becomes 0.4 μm / V or more, and it becomes even easier to remove the foreign matters adhering to the first main surface PS1 of the light-transmitting body 10.

[0115] On the other hand, if the maximum dimension L1 of the gap G0 becomes too large, there is a possibility that a standing wave may be generated in the gap G0 where the sound wave traveling from the light-transmitting body 10 toward the inner layer lens 51 overlaps with the sound wave reflected by the inner layer lens 51 and traveling toward the light-transmitting body 10.

[0116] FIG. 9 is a schematic diagram for explaining the standing wave. In FIG. 9, for the sake of easy explanation, an example of the optical module 4 in which the surface of the inner layer lens 51A facing the light-transmitting body 10 is configured as a flat surface will be described.

[0117] As shown in FIG. 9, when the light-transmitting body 10 vibrates in the vibration direction A1, a sound wave is generated from the light-transmitting body 10 in the gap G10. The sound wave generated from the light-transmitting body 10 travels toward the inner layer lens 51A of the inner layer optical component 50A and is reflected by the surface of the inner layer lens 51A. As a result, the sound wave traveling from the light-transmitting body 10 toward the inner layer lens 51A overlaps with the sound wave reflected by the surface of the inner layer lens 51A, and a standing wave Ws including nodes and antinodes is generated.

[0118] At the standing wave Ws, in the region Z10 that becomes the antinode of the sound wave, the sound pressure becomes higher compared to other regions, and the air is compressed. Therefore, in the region Z10 that becomes the antinode of the sound wave, the compressed air acts as a damper, and vibration attenuation (damping) is likely to occur. Thus, when the light-transmitting body 10 is positioned in the region Z10 that becomes the antinode of the sound wave, the vibration of the light-transmitting body 10 will be attenuated.

[0119] Here, if the wavelength of the sound wave is “λ”, the antinode of the sound wave occurs at a position corresponding to λ / 2. The calculation formula for the wavelength λ is [wavelength (mm)] = [speed of sound (m / s) / frequency (Hz)].

[0120] When the sound pressure in the region Z10 vibrating due to the standing wave Ws increases, the springiness of the air increases as the air pressure increases. The springiness of the air is proportional to the air pressure and inversely proportional to the volume. This is clear from the formula for the spring constant of a bellows-shaped air spring [air spring constant K] = 10×γ(P + 0.1)A / V]. Here, P represents the internal pressure, A represents the effective pressure-receiving area of the air spring, and V represents the internal volume of the air spring.

[0121] When considering the attenuation in the vibration of free vibration, the critical damping ratio is calculated as Cc = 2√mk. Here, m represents the mass and k represents the spring constant. The larger this critical damping ratio Cc, the easier the vibration is to attenuate. Therefore, it is considered that an increase in the spring constant of the air leads to vibration attenuation. From the above, it can be said that vibration attenuation occurs due to the increase in sound pressure in the region Z10 that becomes the antinode of the standing wave Ws.

[0122] FIG. 10 is a graph showing an example of the analysis result of the relationship between the displacement of the light-transmitting body 10 and the sound pressure. FIG. 11 is a graph obtained by enlarging the graph of FIG. 10. The graphs shown in FIGS. 10 and 11 were obtained by performing piezoelectric / ultrasonic wave analysis (harmonic analysis, strong coupling) using Femtet manufactured by Murata Software Co., Ltd. In the analysis, a model in which a glass plate was arranged on the upper surface in the Z direction of the light-transmitting body 10 was used, and the distance between the glass plate and the upper surface of the light-transmitting body was changed. Also, an air layer was inserted into the gap between the glass plate and the upper surface of the light-transmitting body 10. Regarding the materials of the model, the material forming the glass plate was borosilicate glass, the material forming the vibrating body 20 was stainless steel, and the piezoelectric element 30 was PZT. Further, the light-transmitting body 10 and the vibrating body 20 were adhered with an epoxy resin. The resonance frequency of the vibrating body 20 used in the analysis was 27 kHz, and from the speed of sound in air, the wavelength λ of the sound wave was 9.2 mm.

[0123] As shown in FIGS. 10 and 11, when the Z-direction distance of the gap between the light-transmitting body 10 and the glass plate is changed, in regions P1 and P2 corresponding to an integer multiple of the half wavelength λ / 2 of the standing wave Ws, the sound pressure increases and vibration attenuation occurs, whereby the displacement amount of the light-transmitting body 10 becomes smaller. Specifically, in the regions near 4.6 mm and 9.6 mm of the Z-direction distance of the gap between the light-transmitting body 10 and the glass plate, the sound pressure increases and the displacement amount of the light-transmitting body 10 becomes smaller. Also, in the region P0 where the gap between the light-transmitting body 10 and the glass plate is near 0 mm, the displacement amount of the light-transmitting body 10 is also smaller.

[0124] From the above, it is considered that the vibration attenuation of the light-transmitting body 10 can be suppressed by arranging the light-transmitting body 10 while avoiding the region P0 where the gap is near 0 mm and the regions P1 and P2 which are the half wavelength of the standing wave Ws.

[0125] As an example, a value obtained by reducing the maximum displacement amount S0 of the light-transmitting body 10 by 60% is set as the lower limit value S1 of the displacement amount of the light-transmitting body 10. Note that the lower limit value S1 may be set within a range in which droplets attached to the light-transmitting body 10 can be removed. In FIG. 8, since the maximum displacement amount S0 is 7.4 μm, the lower limit value S1 is 4.7 μm. In this case, in the region Pz for suppressing the vibration attenuation of the light-transmitting body 10, the distance in the Z direction of the gap is 0.1 mm or more and 4.5 mm or less. Within this numerical range, it is possible to suppress the vibration attenuation of the light-transmitting body 10 due to the generation of the standing wave Ws.

[0126] Here, the vibration attenuation of the light-transmitting body 10 occurs every integer multiple of the half wavelength λ / 2 of the standing wave Ws. For this reason, in the optical module 4, the dimension of the gap G10 for suppressing the vibration attenuation of the light-transmitting body 10 is determined within the range of [(n×λ / 2)+0.1 mm] or more and [{(n + 1)×λ / 2}-0.1 mm] or less. Note that "n" is an integer of 0 or more, and "λ" is the wavelength of the sound wave generated by vibration.

[0127] From the above, in the optical module 1 of the present embodiment, the maximum dimension L1 of the gap G0 between the light-transmitting body 10 and the inner layer lens 51 is 0.5 mm or more and is determined within the range of [(n×λ / 2)+0.1 mm] or more and [{(n + 1)×λ / 2}-0.1 mm] or less. In other words, when the relationship of 0.5 mm ≦ L1 and [(n×λ / 2)+0.1 mm] ≦ L1 ≦ [{(n + 1)×λ / 2}-0.1 mm] holds for the maximum dimension L1 of the gap G0, it is considered that the vibration attenuation of the light-transmitting body 10 due to the standing wave Ws can be suppressed.

[0128] In the present embodiment, the maximum dimension L1 of the gap G0 is the dimension at the center of the light-transmitting body 10 and the inner layer lens 51, and the vibration attenuation due to the standing wave Ws can be suppressed at the center of the light-transmitting body 10. As a result, the displacement amount at the center of the light-transmitting body 10 can be increased.

[0129] Preferably, the maximum dimension L1 of the gap G0 is 0.5 mm ≤ L1 ≤ (λ / 2 - 0.1) mm (when n = 0). Thereby, while miniaturizing the optical module 1, an increase in sound pressure in the gap G0 can be suppressed, and vibration attenuation can be suppressed.

[0130] [Effect] According to the optical module 1 and the optical device 100 according to Embodiment 1, the following effects can be achieved.

[0131] The optical module 1 includes a light-transmitting body 10, a vibrating body 20, a piezoelectric element 30, and an inner-layer optical component 50. The vibrating body 20 is formed in a cylindrical shape and supports the light-transmitting body 10. The piezoelectric element 30 is disposed on the vibrating body 20 and vibrates the vibrating body 20. The inner-layer optical component 50 includes an inner-layer lens 51 facing the light-transmitting body 10. On the surface of the inner-layer lens 51 facing the light-transmitting body 10, a first concave portion 51a that is recessed in the thickness direction (Z direction) of the inner-layer lens 51 and has a curvature is formed. A gap G0 is formed between the light-transmitting body 10 and the first concave portion 51a of the inner-layer lens 51.

[0132] With such a configuration, vibration attenuation can be suppressed. According to the optical module 1, it is possible to suppress the concentration of sound pressure in the gap G0 formed between the light-transmitting body 10 and the inner-layer lens 51. Specifically, by forming the first concave portion 51a on the surface of the inner-layer lens 51 facing the light-transmitting body 10, the sound waves reflected by the inner-layer lens 51 in the gap G0 are likely to be dispersed. Thereby, the sound pressure in the gap G0 is reduced, and vibration attenuation of the light-transmitting body 10 can be suppressed. As a result, the displacement amount of the light-transmitting body 10 can be increased, and the removal efficiency of the droplets attached to the light-transmitting body 10 can be improved.

[0133] When viewed from the thickness direction (Z direction) of the light-transmitting body 10, the first concave portion 51a is formed at a position overlapping the central portion of the light-transmitting body 10. With such a configuration, it is possible to suppress the concentration of sound waves near the central portion of the light-transmitting body 10 and suppress vibration attenuation at the central portion of the light-transmitting body 10.

[0134] When viewed from the thickness direction (Z direction) of the light-transmitting body 10, the center C2 of the first concave portion 51a substantially coincides with the center C1 of the light-transmitting body 10. With such a configuration, while improving the optical characteristics, it is possible to suppress the concentration of sound waves in the central portion of the light-transmitting body 10, and it is possible to suppress the vibration attenuation in the central portion of the light-transmitting body 10.

[0135] The depth of the first concave portion 51a becomes smaller toward the outside from the center C2 of the inner layer lens 51 when viewed from the thickness direction (Z direction) of the inner layer lens 51. With such a configuration, the sound waves reflected by the first concave portion 51a are likely to be dispersed, and it is possible to suppress the concentration of sound waves in the gap G0. Thereby, the vibration attenuation of the light-transmitting body 10 can be suppressed.

[0136] The first concave portion 51a is formed in a spherical shape or an aspherical shape. With such a configuration, the sound waves reflected by the first concave portion 51a are more likely to be dispersed, and it is possible to further suppress the concentration of sound waves in the gap G0. Thereby, the vibration attenuation of the light-transmitting body 10 can be further suppressed.

[0137] On the surface PS2 of the light-transmitting body 10 facing the inner layer lens 51, a second concave portion 11 that is recessed in the thickness direction (Z direction) of the light-transmitting body 10 and has a curvature is formed. With such a configuration, it is possible to disperse sound waves in the second concave portion 11 of the light-transmitting body 10, and it is possible to further suppress the concentration of sound waves in the gap G0. Thereby, the vibration attenuation of the light-transmitting body 10 can be further suppressed.

[0138] The second concave portion 11 of the light-transmitting body 10 has a shape that is recessed in a hemispherical shape. With such a configuration, it is easy to disperse sound waves in the second concave portion 11, and it is possible to suppress the concentration of sound waves in the gap G0. Thereby, the vibration attenuation of the light-transmitting body 10 can be suppressed.

[0139] When viewed from the thickness direction (Z direction) of the light-transmitting body 10, the outer diameter D22 of the inner layer lens 51 is larger than the outer diameter D12 of the second concave portion 11 of the light-transmitting body 10. With such a configuration, while improving the optical characteristics, it is possible to suppress the vibration attenuation of the light-transmitting body 10.

[0140] The curvature of the first concave portion 51a of the inner layer lens 51 is larger than the curvature of the second concave portion 11 of the light-transmitting body 10. With such a configuration, it becomes easier to secure an optical path passing from the light-transmitting body 10 through the inner layer lens 51.

[0141] The maximum dimension L1 of the gap G0 is 0.5 mm or more. With such a configuration, it becomes easier to suppress an increase in sound pressure within the gap G0 and easier to suppress vibration attenuation of the light-transmitting body 10.

[0142] The maximum dimension L1 of the gap G0 is defined within the range of [(n×λ / 2)+0.1 mm] or more and [{(n + 1)×λ / 2}-0.1 mm] or less, where n is an integer of 0 or more and λ represents the wavelength of the sound wave generated by vibration. Preferably, the maximum dimension L1 of the gap G0 is 0.5 mm ≤ L1 ≤ (λ / 2 - 1) mm (when n = 0). With such a configuration, when a standing wave Ws is generated, it is possible to avoid the antinode of the sound wave, and it is possible to suppress vibration attenuation of the light-transmitting body 10 due to an increase in sound pressure.

[0143] The maximum dimension L1 of the gap G0 is the dimension between the light-transmitting body 10 and the first concave portion 51a on a straight line passing through the center C1 of the light-transmitting body 10 and the center C2 of the first concave portion 51a when viewed from the thickness direction (Z direction) of the light-transmitting body 10. With such a configuration, it is possible to suppress the concentration of sound waves on a straight line passing through the center C1 of the light-transmitting body 10 and the center C2 of the first concave portion 51a within the gap G0. Thereby, it is possible to suppress vibration attenuation near the center C1 of the light-transmitting body 10.

[0144] The inner layer lens 51 has a flat surface FS1 orthogonal to the thickness direction (Z direction) of the inner layer lens 51 on the surface facing the light-transmitting body 10. The inner layer optical component 50 includes a cylindrical lens holding portion 52 that houses the inner layer lens 51. The lens holding portion 52 has a pressing portion 52a that contacts the flat surface FS1 inside the lens holding portion 52. With such a configuration, while suppressing the concentration of sound pressure in the first concave portion 51a, the inner layer lens 51 can be stably held by the pressing portion 52a of the lens holding portion 52. Thereby, it is possible to suppress the dropout of the inner layer lens 51 and suppress positional deviation, and thus maintain an optical path.

[0145] The optical device 100 includes an optical module 1 and an optical element 2 disposed on the optical module 1. With such a configuration, the same effects as those of the above-described optical module 1 can be achieved.

[0146] <Modification Example 1> FIG. 12 is a schematic cross-sectional view showing the main configuration of the optical module 1A of Modification Example 1. As shown in FIG. 12, the second recess 11 may not be provided in the light-transmitting body 10A, and the entire surface of the second main surface PS2 of the light-transmitting body 10A may be formed as a flat surface. Alternatively, in the second main surface PS2 of the light-transmitting body 10A, the portion facing the inner layer lens 51 may be formed as a flat surface.

[0147] Even in such a configuration, sound waves can be dispersed in the first recess 51a of the inner layer lens 51, and concentration of sound waves in the gap G0 can be suppressed. Thereby, vibration attenuation of the light-transmitting body 10A can be suppressed.

[0148] <Modification Example 2> FIG. 13 is a schematic cross-sectional view showing the main configuration of the optical device 100A of Modification Example 3. As shown in FIG. 13, in the optical module 1B in the optical device 100A, a curved portion R1 is provided at a corner portion of the vibrating body 20A. The curved portion R1 is provided at a portion where each component of the vibrating body 20A is connected. The curved portion R1 has a round curved shape.

[0149] By providing the curved portion R1 at the corner portion of the vibrating body 20A, stress can be dispersed when the vibrating body 20A vibrates. Thereby, since stress can be reduced, fatigue failure of the vibrating body 20A can be suppressed, and reliability can be improved.

[0150] The present invention is fully described in connection with preferred embodiments with reference to the accompanying drawings, but various modifications and corrections will be apparent to those skilled in the art. Such modifications and corrections should be understood to be included therein as long as they do not depart from the scope of the present invention defined by the appended claims.

Industrial Applicability

[0151] The vibration device and vibration control method of the present invention can be applied to in-vehicle cameras, surveillance cameras, or optical sensors such as LiDAR used outdoors.

Explanation of Signs

[0152] 1, 1A, 1B Optical module 2 Optical element 3 Control unit 4 Optical module 10, 10A Translucent body 11, 11A Concave portion (second concave portion) 20, 20A Vibration body 21 Vibration flange 22 First cylindrical body 23 Spring portion 24 Second cylindrical body 25 Diaphragm 26 Connection portion 30 Piezoelectric element 40 Fixing portion 50, 50A Inner layer optical component 51, 51A Inner layer lens 51a Concave portion (first concave portion) 52 Lens holding portion 52a Pressing portion 52b Contact portion 53 Inner layer flange 100, 100A Optical device A1 Vibration direction C1 Center D11, D12, D21, D22 Outer diameter FS1 Flat surface G0, G10 Gap PS1 First main surface PS2 Second main surface

Claims

1. A light-transmitting body, a vibrating body formed in a cylindrical shape and supporting the light-transmitting body, a piezoelectric element disposed on the vibrating body and vibrating the vibrating body, an inner layer optical component disposed inside the vibrating body, comprising: the inner layer optical component includes an inner layer lens facing the light-transmitting body, on the surface of the inner layer lens facing the light-transmitting body, a first concave portion is formed that is recessed in the thickness direction of the inner layer lens and has a curvature, a gap is formed between the light-transmitting body and the first concave portion of the inner layer lens, the maximum dimension of the gap is 0.5 mm or more and is defined in the range of [(n × λ / 2) + 0.1 mm] or more and [{(n + 1) × λ / 2} - 0.1 mm] or less, n is an integer of 0 or more, and λ represents the wavelength of the sound wave generated by vibration, an optical module.

2. When viewed from the thickness direction of the light-transmitting body, the first concave portion is formed at a position overlapping the central portion of the light-transmitting body. The optical module according to Claim 1.

3. When viewed from the thickness direction of the light-transmitting body, the center of the first concave portion substantially coincides with the center of the light-transmitting body. The optical module according to Claim 2.

4. The depth of the first concave portion decreases outward from the center of the inner layer lens when viewed from the thickness direction of the inner layer lens. The optical module according to Claim 1.

5. The first concave portion is formed in a spherical shape or an aspherical shape. The optical module according to Claim 1.

6. On the surface of the light-transmitting body facing the inner layer lens, a second concave portion is formed that is recessed in the thickness direction of the light-transmitting body and has a curvature. The optical module according to Claim 1.

7. The second concave portion of the light-transmitting body has a shape that is recessed in a hemispherical shape. The optical module according to Claim 6.

8. When viewed from the thickness direction of the light-transmitting body, the outer diameter of the inner layer lens is larger than the outer diameter of the second concave portion of the light-transmitting body. The optical module according to Claim 6.

9. The curvature of the first concave portion of the inner layer lens is larger than the curvature of the second concave portion of the light-transmitting body. The optical module according to Claim 6.

10. The maximum dimension of the gap is the dimension between the light-transmitting body and the first concave portion on a straight line passing through the center of the light-transmitting body and the center of the first concave portion when viewed from the thickness direction of the light-transmitting body. The optical module according to Claim 1.

11. The inner layer lens has a flat surface orthogonal to the thickness direction of the inner layer lens on the surface facing the light transmissive body. The inner layer optical component includes a cylindrical lens holding portion for housing the inner layer lens. The lens holding portion has a pressing portion that contacts the flat surface inside the lens holding portion. The optical module according to claim 1.

12. An optical module according to any one of claims 1 to 11, an optical element disposed in the optical module, and an optical device comprising the same.

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