Optical module and optical device

Abstract

An optical module according to the present invention comprises: a translucent body; a vibrating body that is formed into a cylindrical shape and supports the translucent body; a piezoelectric element that is disposed on the vibrating body and vibrates the vibrating body; and an inner layer optical component that is disposed to the inner side of the vibrating body. In the translucent body, a recessed section, that is indented in the thickness direction of the translucent body and is curved, is formed in a surface opposing the inner layer optical component. The inner layer optical component includes an inner layer lens opposing the translucent body, and the inner layer lens includes a first portion that protrudes toward the translucent body and is curved, and a second portion that is provided at the outer periphery of the first portion. On the outer periphery of the first portion, a first gap is formed between the first portion and the translucent body, and a second gap is formed between the second portion and the translucent body; and the second gap is larger than the first gap.

Description

[Technical field]

[0001] The present invention relates to an optical module and an optical device that removes droplets and the like by vibration. [Background technology]

[0002] Patent Document 1 discloses a droplet removal device that includes a vibration member that is connected to the end of the curved surface that forms the dome part of an optical element and generates bending vibration in the dome part. In the droplet removal device described in Patent Document 1, a drip-proof cover and a piezoelectric element are bonded and fixed, and the drip-proof cover is subjected to bending vibration by vibration of the piezoelectric element, thereby removing droplets and the like that are attached to the surface of the drip-proof cover. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-170303 A Summary of the Invention [Problem to be solved by the invention]

[0004] The device described in Patent Document 1 still has room for improvement in terms of suppressing vibration damping. [Means for solving the problem]

[0005] An optical module according to one aspect of the present invention includes: A transparent body; A vibrating body formed in a cylindrical shape and supporting the light-transmitting body; A piezoelectric element is disposed on the vibrating body and vibrates the vibrating body; An inner layer optical component disposed inside the vibrating body; Equipped with A concave portion having a curvature and recessed in a thickness direction of the light-transmitting body is formed on a surface of the light-transmitting body facing the inner layer optical component, The inner layer optical component includes an inner layer lens facing the light-transmitting body, The inner layer lens includes a first portion that protrudes toward the light-transmitting body and has a curvature, and a second portion that is provided on an outer periphery of the first portion, a first gap is formed between the first portion and the light-transmitting body at the outer periphery of the first portion, A second gap is formed between the second portion and the light-transmitting body, The second gap is larger than the first gap.

[0006] An optical device according to one aspect of the present invention comprises: The optical module according to the above aspect; an optical element disposed in the optical module; Equipped with. Effect 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 damping. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic perspective view showing an example of an optical device according to a first embodiment of the present invention. [Diagram 2] 1 is a schematic cross-sectional view showing an example of a configuration of an optical device according to a first embodiment of the present invention. [Diagram 3] 1 is a block diagram showing an example of a functional configuration of an optical device according to a first embodiment of the present invention. [Figure 4] 10 is a schematic diagram for explaining a gap between a light-transmitting body and an inner layer lens. FIG. [Diagram 5] FIG. 2 is a schematic diagram for explaining Comparative Example 1, Comparative Example 2, and Example 1. [Figure 6] 11 is a graph illustrating an example of a simulation result of the displacement amount and sound pressure of a light-transmitting body in Comparative Example 1, Comparative Example 2, and Example 1. [Figure 7] 1A to 1C are diagrams illustrating an example of a displacement distribution and a sound pressure distribution in Comparative Example 1, Comparative Example 2, and Example 1. [Figure 8]13 is a graph showing an example of the relationship between the dimension of a second gap and the displacement amount of a light-transmitting body. [Figure 9] 13 is a graph illustrating an example of the relationship between the curvature of a concave portion of a light-transmitting body and the curvature of a first portion of an inner layer lens. [Figure 10] 10 is a schematic cross-sectional view showing a main configuration of an optical module according to a first modified example. [Figure 11] 11 is a schematic cross-sectional view showing a main configuration of an optical module according to a second modified example. FIG. [Figure 12] FIG. 11 is a schematic cross-sectional view showing a main configuration of an optical device according to a third modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] (How the present invention was arrived at) In vehicles equipped with an imaging unit equipped with an imaging element or the like at the front or rear of the vehicle, images acquired by the imaging unit are used to control safety devices or perform automatic driving control. Such imaging units may be placed outside the vehicle. In this case, a protective cover or a transparent body such as a lens is placed on the exterior of the imaging unit.

[0010] For this reason, foreign matter such as raindrops (liquid droplets), mud, dust, etc. may adhere to the transparent body. If foreign matter adheres to the transparent body, the foreign matter may be reflected in the image captured by the imaging unit, making it difficult to obtain a clear image.

[0011] In recent years, devices have been developed that remove foreign matter attached to a transparent body by vibrating the transparent body. In such devices, the transparent body is placed on a cylindrical vibrating body, and the vibrating body is vibrated by a piezoelectric element or the like to vibrate the transparent body. In addition, an inner layer optical component such as an inner layer lens is placed 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 occurs depending on the size of the gap. This causes a problem that foreign matter attached to the light-transmitting body cannot be sufficiently removed. This is a new problem discovered by the inventors.

[0013] For example, when a transparent body is vibrated, a sound wave is generated by the vibration. The sound wave generated from the transparent body is reflected by the inner layer optical component, and a standing wave including an antinode and a node of the sound wave is generated. At the antinode of the sound wave, the sound pressure is higher than at 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. Therefore, when an antinode of the sound wave is formed at the position where the transparent body is disposed in the gap between the transparent body and the inner layer optical component, the vibration of the transparent body is attenuated. As a result, there are cases where foreign matter attached to the transparent body cannot be sufficiently removed.

[0014] In addition, in order to position the inner layer optical components so as to avoid the antinodes and nodes caused by the reflection of the sound waves generated from the transparent body, it has been considered to position the inner layer optical components close to the transparent body and reduce the gap between the transparent body and the inner layer optical components. In this case, regardless of the presence or absence of standing waves, the volume of air in the gap decreases and the sound pressure increases. As a result, vibration attenuation may occur.

[0015] As a result of extensive research, the present inventors have found a configuration for suppressing the attenuation of vibrations by suppressing an increase in sound pressure in the gap between the light-transmitting body and the inner layer optical component, and have arrived at the following invention.

[0016] The optical module of the first aspect of the present invention comprises 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, and an inner layer optical component disposed inside the vibrating body, wherein a recess is formed on a surface of the light-transmitting body facing the inner layer optical component, the recess being recessed in the thickness direction of the light-transmitting body and having a curvature, and the inner layer optical component includes an inner layer lens facing the light-transmitting body, the inner layer lens including a first portion protruding toward the light-transmitting body and having a curvature, and a second portion provided on the outer periphery of the first portion, wherein a first gap is formed between the first portion and the light-transmitting body at the outer periphery of the first portion, and a second gap is formed between the second portion and the light-transmitting body, and the second gap is larger than the first gap.

[0017] With this configuration, vibration damping can be suppressed.

[0018] The second portion may be a step recessed in a direction away from the light-transmitting body relative to the first portion.

[0019] With this configuration, vibration damping can be further suppressed.

[0020] The second portion may have an inclined surface that is inclined in a direction away from the light-transmitting body toward an outer periphery of the inner layer lens.

[0021] With this configuration, vibration damping can be further suppressed.

[0022] The second gap may be 1.2 times or more larger than the first gap.

[0023] With this configuration, vibration damping can be further suppressed.

[0024] When viewed in 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 recess of the light-transmitting body.

[0025] With this configuration, it is possible to suppress vibration damping while maintaining the optical characteristics of the inner layer lens.

[0026] The curvature of the first portion of the inner layer lens may be greater than the curvature of the recess of the light-transmitting body.

[0027] With this configuration, vibration damping can be further suppressed.

[0028] The second portion has a flat surface perpendicular to the thickness direction of the inner layer lens, and the inner layer optical component includes a cylindrical lens holding portion that stores the inner layer lens, and the lens holding portion may have a pressing portion on the inside of the lens holding portion that contacts the flat surface.

[0029] With this configuration, the optical properties of the inner lens can be maintained and preserved.

[0030] The first portion may be disposed within the recess of the optically transparent body.

[0031] With this configuration, it is possible to reduce the size of the module while suppressing vibration damping.

[0032] The inner layer lens may be composed of a spherical lens or an aspherical lens.

[0033] With this configuration, vibration damping can be further suppressed.

[0034] The recess of the light-transmitting body may have a hemispherical recessed shape.

[0035] With this configuration, vibration damping can be further suppressed.

[0036] An optical device according to one aspect of the present disclosure includes the optical module according to the above aspect, and an optical element disposed in the optical module.

[0037] With this configuration, vibration damping can be suppressed.

[0038] 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 application, or its uses. Furthermore, the drawings are schematic, and the ratios of dimensions do not necessarily correspond to the real ones.

[0039] (Embodiment 1) [Optical device] Fig. 1 is a schematic perspective view showing an example of an optical device 100 according to a first embodiment of the present invention. Fig. 2 is a schematic cross-sectional view showing an example of a configuration of the optical device 100 according to the first embodiment of the present invention. The X, Y, and Z directions in the figure indicate the vertical, horizontal, and height directions of the optical device 100.

[0040] 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.

[0041] In this embodiment, an example will be described in which the optical device 100 is an imaging device. The optical device 100 is attached to, for example, the front or rear of a vehicle, and captures an image of an imaging target. Note that the location where the optical device 100 is attached is not limited to a vehicle, and the optical device 100 may be attached to other devices such as a ship or an aircraft.

[0042] 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 ranging from the visible region to the far infrared region.

[0043] When the optical device 100 is mounted on a vehicle or the like and used outdoors, foreign matter such as raindrops, mud, dust, etc. may adhere to the light-transmitting body 10 of the optical module 1 that is disposed in the viewing direction of the optical element 2 and covers the outside. The optical module 1 can generate vibrations to remove foreign matter such as raindrops that have adhered to the light-transmitting body 10.

[0044] [Optical module] 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 component.

[0045] <Translucent body> The light-transmitting body 10 has a light-transmitting property that transmits energy rays or light of a wavelength detected by the optical element 2. 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 adhesion of foreign matter. In the optical device 100, the optical element 2 detects energy rays or light through the light-transmitting body 10.

[0046] Examples of materials that can be used to form the light-transmitting body 10 include light-transmitting plastic, quartz, glass such as borosilicate, light-transmitting ceramic, and synthetic resin. The strength of the light-transmitting body 10 can be increased by forming the light-transmitting body 10 from, for example, reinforced glass. In this embodiment, the light-transmitting body 10 is formed from BK-7 (borosilicate glass).

[0047] 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.

[0048] In this embodiment, the translucent body 10 has a first main surface PS1 and a second main surface PS2 opposite to the first main surface PS1. The first main surface PS1 is a main surface located on the outside of the translucent body 10. The first main surface PS1 is formed of a continuous curved surface. Specifically, the first main surface PS1 is curved in a round shape. The second main surface PS2 is a main surface located on the inside of the translucent body 10. The second main surface PS2 has a recess 11 provided on a flat surface.

[0049] Specifically, the second principal surface PS2 is a surface of the light-transmitting body 10 that faces the inner layer optical component 50. A recess 11 that is recessed in the thickness direction (Z direction) of the light-transmitting body 10 and has a curvature is formed on the second principal surface PS2. For example, the recess 11 is provided in 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 recess 11 has a hemispherically recessed shape.

[0050] The outer peripheral end of the light-transmitting body 10 is joined to the vibration body 20. Specifically, the second main surface PS2 of the light-transmitting body 10 and the vibration flange 21 of the vibration 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 light-transmitting body 10 and the vibration body 20 can be joined together using, for example, an adhesive or a brazing material. Alternatively, thermocompression bonding, anodic bonding, or the like can also be used.

[0051] <Vibration body> The vibrating body 20 is formed in a cylindrical shape and supports the light-transmitting body 10. The vibrating body 20 is vibrated by the piezoelectric element 30, thereby vibrating the light-transmitting body 10.

[0052] The vibrating body 20 has a vibrating flange 21, a first cylindrical body 22, a spring portion 23, a second cylindrical body 24, a vibration plate 25, and a connecting portion 26. It should be noted that in the vibrating body 20, the connecting portion 26 is not an essential component.

[0053] The vibrating flange 21 is formed of an annular plate member when viewed from the height direction (Z direction) of the optical module 1. The vibrating flange 21 is disposed along the outer periphery of the light-transmitting body 10 and joined to the light-transmitting body 10. The vibrating flange 21 stably supports the light-transmitting body 10 by being in surface contact with the light-transmitting body 10.

[0054] The first cylindrical body 22 is formed in a cylindrical shape having one end and the other end. The first cylindrical body 22 is made of a hollow member with a through hole provided therein. The through hole is provided in the height direction (Z direction) of the optical module 1, and the opening of the through hole is 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 opening of the through hole are formed in a circular shape.

[0055] A vibration flange 21 is provided at one end of the first cylindrical body 22, and a 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.

[0056] 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 be elastically deformable. The spring portion 23 supports the other end of the cylindrical first cylindrical body 22 and extends from the supported position toward the outside of the first cylindrical body 22.

[0057] The spring portion 23 is formed in a plate shape. The spring portion 23 has a hollow circular shape with a through hole provided therein, and extends so as to surround the periphery of 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-shaped 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 opening of the through hole are formed in a circular shape.

[0058] 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.

[0059] The second cylindrical body 24 is formed in a cylindrical shape having one end and the other end. When viewed from the height direction (Z direction) of the optical module 1, the second cylindrical body 24 is located outside the first cylindrical body 22 and supports the spring portion 23. The spring portion 23 is connected to one end of the second cylindrical body 24. The vibration plate 25 is connected to the other end of the second cylindrical body 24.

[0060] The second cylindrical body 24 is made of a hollow member with a through hole provided therein. The through hole is provided in the height direction (Z direction) of the optical module 1, and the through hole opening is 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 into a circle.

[0061] 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 toward the inside of the second cylindrical body 24 from the supported position.

[0062] The diaphragm 25 has a hollow circular shape with a through hole provided therein, and is provided along the inner circumference of the second cylindrical body 24. The diaphragm 25 has an annular plate shape.

[0063] The connection part 26 connects the diaphragm 25 and the fixed part 40. The connection part 26 extends outward from the outer peripheral end of the diaphragm 25 and is bent toward the fixed part 40. The connection part 26 is supported by the fixed part 40. The connection part 26 is configured to have a node, making it difficult for vibrations from the diaphragm 25 to be transmitted.

[0064] In this embodiment, the first cylindrical body 22, the spring portion 23, the second cylindrical body 24, the diaphragm 25, and the connection 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 connection portion 26 may be formed as separate bodies or as separate members.

[0065] The elements constituting the vibrating body 20 described above are made of, for example, metal or ceramic. Examples of metals that can be used include stainless steel, 42 alloy, 50 alloy, invar, super invar, kovar, aluminum, and duralumin. Alternatively, the elements constituting the vibrating body 20 may be made of ceramics such as alumina and zirconia, or may be made of semiconductors such as Si. Furthermore, the elements constituting the vibrating body 20 may be covered with an insulating material. Furthermore, the elements constituting the vibrating body 20 may be subjected to blackbody treatment.

[0066] Furthermore, the shape and arrangement of the elements that make up the vibrating body 20 are not limited to the above example.

[0067] <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 a main surface of the vibration plate 25. Specifically, the piezoelectric element 30 is provided on the main surface of the vibration plate 25 opposite to the side on which the translucent body 10 is located. The piezoelectric element 30 vibrates the vibration plate 25, thereby vibrating the second cylindrical body 24 in the penetration direction (Z direction). For example, the piezoelectric element 30 vibrates when a voltage is applied thereto.

[0068] The piezoelectric element 30 has a hollow circular shape with a through hole provided therein. In other words, the piezoelectric element 30 has a circular 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.

[0069] The outer shape of the piezoelectric element 30 and the opening of the through hole are not limited to this.

[0070] The piezoelectric element 30 has a piezoelectric body and electrodes. Examples of materials for forming the piezoelectric body include barium titanate (BaTiO3), lead zirconate titanate (PZT: PbTiO3·PbZrO3), lead titanate (PbTiO3), lead metaniobate (PbNb2O6), bismuth titanate (Bi4Ti3O 12Suitable piezoelectric ceramics such as (K,Na)NbO3, or suitable piezoelectric single crystals such as LiTaO3, LiNbO3, etc. can be used. The electrodes may be, for example, Ni electrodes. The electrodes may be electrodes made of a thin metal film such as Ag or Au formed by a sputtering method. Alternatively, the electrodes can be formed by plating or vapor deposition in addition to sputtering.

[0071] The fixing portion 40 fixes the vibration body 20. The fixing portion 40 also fixes the inner layer optical component 50. The fixing portion 40 is formed in a tubular shape. For example, the fixing portion 40 has a cylindrical shape. The shape of the fixing portion 40 is not limited to a cylindrical shape. The fixing portion 40 may be formed integrally with the vibration body 20.

[0072] <Inner layer optical components> 2, the inner layer optical component 50 is an optical component disposed inside the vibration body 20. For example, the inner layer optical component 50 is a lens module.

[0073] In this embodiment, the inner layer optical component 50 has an inner layer lens 51 , a lens holding portion 52 , and an inner layer flange 53 .

[0074] The inner layer lens 51 is composed of multiple lenses. The inner layer lens 51 is disposed on the optical path of the optical element 2 inside the vibration body 20, and faces the light-transmitting body 10. The inner layer lens 51 includes a first portion 51a and a second portion 51b on the side facing the light-transmitting body 10. Specifically, of the multiple lenses constituting the inner layer lens 51, the lens disposed at the position facing the light-transmitting body 10 includes the first portion 51a and the second portion 51b.

[0075] The first portion 51a is a portion of the inner layer lens 51 that protrudes toward the light-transmitting body 10 and has a curvature. The first portion 51a has a circular shape when viewed in the thickness direction (Z direction) of the inner layer lens 51. The first portion 51a has a shape that increases in thickness toward the center of the inner layer lens 51. For example, the first portion 51a has a spherical shape. The first portion 51a also has an outer wall that extends in the thickness direction (Z direction) of the inner layer lens 51. The first portion 51a is connected to the second portion 51b at the lower end of the outer wall.

[0076] The second portion 51b is a portion provided on the outer periphery of the first portion 51a in the inner layer lens 51. The second portion 51b is formed in an annular shape when viewed in the thickness direction (Z direction) of the inner layer lens 51.

[0077] In this embodiment, the second portion 51b is a step recessed in a direction away from the light-transmitting body 10 in the thickness direction (Z direction) of the inner layer lens 51, further away from the light-transmitting body 10 than the first portion 51a. The second portion 51b has a flat surface FS1 formed at a position farther away from the light-transmitting body 10 than the first portion 51a in the thickness direction (Z direction) of the inner layer lens 51. The flat surface FS1 is perpendicular to the thickness direction (Z direction) of the inner layer lens 51. In other words, the flat surface FS1 extends in the X and Y directions.

[0078] The inner layer lens 51 is, for example, a spherical lens. Note that the inner layer lens 51 is not limited to a spherical lens, and may be an aspherical lens.

[0079] The lens holding portion 52 holds the inner layer lens 51. The lens holding portion 52 is formed in a tubular 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 layer lens 51.

[0080] The lens holding portion 52 has a pressing portion 52a that contacts the flat surface FS1 of the second portion 51b on the inside of the lens holding portion 52. The pressing portion 52a is a member that protrudes toward the inside of 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 second portion 51b and presses the flat surface FS1 in the thickness direction (Z direction) of the inner layer lens 51.

[0081] In this embodiment, a contact portion 52b that contacts the inner layer lens 51 is provided at the other end of the lens holding portion 52. The contact portion 52b protrudes inward of the lens holding portion 52 at 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 stored in the lens holding portion 52 and is pressed against the contact portion 52b by the pressing portion 52a. This causes the inner layer lens 51 to be 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 be attached to the lens holding portion 52 by a screw structure.

[0082] 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 fixed portion 40. The inner layer flange 53 is formed in a circular ring 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 fixed portion 40. The inner layer flange 53 is fixed to the inside of the vibrating body 20 by being supported by the fixed portion 40.

[0083] FIG. 3 is a block diagram showing an example of a functional configuration of the optical device 100 according to the first embodiment of the present invention. As shown in FIG. 3, the piezoelectric element 30 is controlled by a control unit 3. The control unit 3 applies a drive signal that generates 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. The vibration of the piezoelectric element 30 vibrates the vibrating body 20, and the vibration of the vibrating body 20 is transmitted to the light-transmitting body 10, causing the light-transmitting body 10 to vibrate. As a result, foreign matter such as raindrops attached to the light-transmitting body 10 is removed.

[0084] The control unit 3 can be realized, for example, by a semiconductor element. For example, the control unit 3 can be configured by 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 alone, or may be realized by combining hardware and software.

[0085] For example, the control unit 3 realizes a predetermined function by reading out data and programs stored in the storage unit and performing various arithmetic processing.

[0086] 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.

[0087] [About Gap] Next, the gap formed between the light-transmitting body 10 and the inner lens 51 in the optical module 1 will be described.

[0088] Returning to FIG. 2, between the light-transmitting body 10 and the inner layer lens 51, a gap G0 is formed.

[0089] 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 diagram of the light-transmitting body 10 viewed from the first main surface PS1 side, and FIG. 4(b) shows a schematic cross-sectional view of the vicinity of the light-transmitting body 10. In FIG. 4, the reference character D11 indicates the outer diameter of the light-transmitting body 10, the reference character D12 indicates the outer diameter of the recess 11 of the light-transmitting body 10, the reference character D21 indicates the outer diameter of the first portion 51a of the inner layer lens 51, and the reference character D22 indicates the outer diameter of the second portion 51b of the inner layer lens 51. The reference character A1 indicates the vibration direction of the light-transmitting body 10. The outer diameter D12 of the recess 11 means the diameter that defines the recess 11 on the second main surface PS2 of the light-transmitting body 10. The outer diameter D22 of the second portion 51b of the inner layer lens 51 also means the outer diameter of the inner layer lens 51. Moreover, the symbols D11, D12, D21, and D22 each indicate a dimension when viewed from the height direction (Z direction) of the optical module 1.

[0090] In this embodiment, the height direction of the optical module 1 ( Z direction When viewed from the front side, the outer diameter D12 of the recess 11 is larger than the outer diameter D11 of the first portion 51a of the inner layer lens 51. Furthermore, the outer diameter D22 of the inner layer lens 51 is larger than the outer diameter D12 of the recess 11. This can improve the optical characteristics. By making the outer diameter D22 of the inner layer lens 51 larger than the outer diameter D12 of the recess 11, light entering from the light-transmitting body 10 is more likely to pass through the inner layer lens 51 and enter the optical element 2.

[0091] 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 a surface of the inner layer lens 51 that faces the second main surface PS2 of the light-transmitting body 10.

[0092] In the gap G0, a first gap G1 and a second gap G2 are formed. The first gap G1 is formed on the outer periphery of the first portion 51a of the inner layer lens 51 between the first portion 51a and the translucent body 10. For example, the first gap G1 is formed on the outer periphery of the first portion 51a between the first portion 51a and the recess 11. The second gap G2 is formed between the second portion 51b of the inner layer lens 51 and the translucent body 10. For example, the second gap G2 is formed between the flat surface FS1 of the second portion 51b and the second main surface PS2 of the translucent body 10.

[0093] The second gap G2 is larger than the first gap G1. Specifically, the dimension of the second gap G2 is larger than the dimension of the first gap G1 in the height direction (Z direction) of the optical module 1. By making the dimension of the second gap G2 larger than the dimension of the first gap G1, the volume of air in the gap G0 is prevented from decreasing. This makes it possible to prevent the sound pressure from increasing in the gap G0 and the occurrence of vibration attenuation.

[0094] In this embodiment, a pressing portion 52a is disposed on the second portion 51b, but even if the second gap G2 is reduced by the thickness of the pressing portion 52a, the second gap G2 is larger than the first gap G1.

[0095] [Relationship between the displacement of a transparent body and sound pressure] Displacement of the transparent body 10 amount In order to investigate the relationship between the vibration and sound pressure, a simulation was performed using the analysis models of Comparative Example 1, Comparative Example 2, and Example 1. The analysis models and simulation results of Comparative Example 1, Comparative Example 2, 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., and a piezoelectric / acoustic analysis (harmonic analysis, strong coupling) was performed. In the analysis model, the material of the translucent body 10 was borosilicate glass, the material forming the vibrating body 20 was stainless steel, and the piezoelectric element 30 was PZT. The translucent body 10 and the vibrating body 20 were bonded with epoxy resin. The resonant frequency of the vibrating body 20 was set to 27 kHz.

[0096] FIG. 5 is a schematic diagram for explaining Comparative Example 1, Comparative Example 2, and Example 1. As shown in FIG. 5, Comparative Example 1 uses an analysis model having an inner layer lens whose surface facing the light-transmitting body is a flat surface. Comparative Example 2 uses an analysis model having an inner layer lens whose surface facing the light-transmitting body protrudes toward the light-transmitting body and has a curvature. In the inner layer lens of Comparative Example 2, the surface facing the light-transmitting body is formed only by the first portion 51a and does not have the second portion 51b. Example 1 uses an analysis model having the configuration of the optical module 1 described in this embodiment. Note that Comparative Example 1 and Comparative Example 2 are different only in the configuration of the inner layer lens, and the other configurations are the same as Example 1.

[0097] Fig. 6 is a graph illustrating an example of a simulation result of the displacement amount and sound pressure of the light-transmitting body in Comparative Example 1, Comparative Example 2, and Example 1. Note that 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 part of the light-transmitting body 10.

[0098] 6, in Example 1, the sound pressure in the gap G0 is smaller and the displacement of the light-transmitting body 10 is larger than in Comparative Example 1 and Comparative Example 2. In Example 1, the first portion 51a of the inner layer lens 51 protrudes toward the light-transmitting body 10 and forms a surface having a curvature. Therefore, sound waves reflected by the first portion 51a tend to diffuse.

[0099] In addition, a second portion 51b is provided on the outer periphery of the first portion 51a, the second portion 51b being disposed in a direction away from the light-transmitting body 10 than the first portion 51a. Therefore, a second gap G2 between the second portion 51b and the light-transmitting body 10 is larger than a first gap G1 between the first portion 51a on the outer periphery of the first portion 51a and the light-transmitting body 10. Therefore, sound waves in the gap G0 are easily emitted toward the radial outside of the inner layer lens 51.

[0100] On the other hand, in Comparative Example 1, the surface of the inner layer lens facing the light-transmitting body 10 is formed flat, so sound waves reflected by the inner layer lens are less likely to diffuse. Also, because the gap becomes smaller from the center of the light-transmitting body toward the radial outside, sound waves in the gap are less likely to be emitted radially outward from the inner layer lens.

[0101] In Comparative Example 2, the surface of the inner layer lens facing the light-transmitting body 10 protrudes toward the light-transmitting body 10 and is formed as a surface having a curvature, so that sound waves reflected by the inner layer lens tend to diffuse, which is different from Comparative Example 1. However, like Comparative Example 1, the gap becomes smaller from the center of the light-transmitting body toward the radial outside, so that sound waves in the gap are less likely to be emitted radially outward from the inner layer lens.

[0102] In this way, in Example 1, compared with Comparative Example 1 and Comparative Example 2, the configuration is such that sound waves are more easily emitted from within the gap G0, and the sound waves within the gap G0 can be reduced. As a result, vibration attenuation can be suppressed, and the amount of displacement of the translucent body 10 can be increased.

[0103] Fig. 7 is a diagram illustrating an example of the displacement distribution and the sound pressure distribution in Comparative Example 1, Comparative Example 2, and Example 1. As shown in Fig. 7, the maximum displacement amount of the light-transmitting body in Comparative Example 1 is about 6 µm, the maximum displacement amount in Comparative Example 2 is about 6.5 µm, and the maximum displacement amount in Example 1 is about 7.2 µm.

[0104] On the other hand, when focusing on the sound pressure distribution, it can be seen that in Example 1, sound waves are emitted radially outward from the inner layer lens 51, compared to Comparative Examples 1 and 2. In other words, it can be seen that in Example 1, concentration of sound waves within the gap G0 is suppressed, compared to Comparative Examples 1 and 2.

[0105] [Second gap dimensions] Fig. 8 is a graph showing an example of the relationship between the dimension of the second gap G2 and the displacement of the light-transmitting body. As shown in Fig. 8, the larger the dimension of the second gap G2, the larger the displacement of the light-transmitting body 10. In this embodiment, the dimension of the first gap G1 is 50 µm. It is preferable that the dimension of the second gap G2 is larger than 50 µm. More preferably, the dimension of the second gap G2 is 60 µm or more.

[0106] Alternatively, the dimension of the second gap G2 is preferably 1.2 times or more the dimension of the first gap G1, and more preferably, the dimension of the second gap G2 is 1.5 times or more the dimension of the first gap G1.

[0107] [Relationship between the curvature of the concave portion of the transparent body and the curvature of the first portion of the inner lens] The relationship between the curvature of the recess 11 of the light-transmitting body 10 and the curvature of the first portion 51a of the inner layer lens 51 will be described with reference to FIG.

[0108] Fig. 9 is a graph illustrating an example of the relationship between the curvature of the recess 11 of the light-transmitting body 10 and the curvature of the first portion 51a of the inner layer lens 51. In Fig. 9, the horizontal axis indicates the difference in curvature, and the vertical axis indicates the amount of displacement of the light-transmitting body 10. Note that "difference in curvature" refers to the value obtained by subtracting the curvature of the first portion 51a from the curvature of the recess 11.

[0109] 9, when the difference in curvature is "-1", the curvature of the first portion 51a is greater than the curvature of the recess 11. When the difference in curvature is "0", the curvature of the recess 11 is equal to the curvature of the first portion 51a. When the difference in curvature is "+1", the curvature of the first portion 51a is smaller than the curvature of the recess 11.

[0110] 9, when the difference in curvature is "-1", the sound pressure is lower and the displacement of the light-transmitting body 10 is larger than when the difference in curvature is "0" and "+1". That is, as the curvature of the first portion 51a becomes larger than the curvature of the recess 11, the sound pressure is lower and the displacement is larger.

[0111] For this reason, it is preferable that the curvature of the recess 11 of the light-transmitting body 10 is smaller than the curvature of the first portion 51a of the inner layer lens 51. This makes it possible to reduce the sound pressure in the gap G0 and suppress vibration attenuation. As a result, the amount of displacement of the light-transmitting body 10 can be increased.

[0112] [effect] The optical module 1 and the optical device 100 according to the first embodiment can provide the following advantages.

[0113] 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 is disposed inside the vibrating body 20. 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 on a surface PS2 of the light-transmitting body 10 that faces the inner layer optical component 50. The inner layer optical component 50 includes an inner layer lens 51 that faces the light-transmitting body 10. The inner layer lens 51 includes a first portion 51a that protrudes toward the light-transmitting body 10 and has a curvature, and a second portion 51b that is provided on the outer periphery of the first portion 51a. A first gap G1 is formed between the first portion 51a and the light-transmitting body 10 on the outer periphery of the first portion 51a. A second gap G2 is formed between the second portion 51b and the light-transmitting body 10. The second gap G2 is larger than the first gap G1.

[0114] With this configuration, vibration attenuation can be suppressed. The optical module 1 can suppress concentration of sound pressure in the gap G0 formed between the light-transmitting body 10 and the inner layer lens 51. Specifically, in the inner layer lens 51, by making the second gap G2 larger than the first gap G1, sound waves reflected in the gap G0 are easily released to the outside of the inner layer lens 51. This reduces sound pressure in the gap G0, and vibration attenuation of the light-transmitting body 10 can be suppressed. As a result, the amount of displacement of the light-transmitting body 10 can be increased, and the efficiency of removing droplets attached to the light-transmitting body 10 can be improved.

[0115] The second portion 51b is a step recessed in a direction away from the light-transmitting body 10 more than the first portion 51a. With this configuration, the second gap G2 can be made larger than the first gap G1, and vibration damping of the light-transmitting body 10 can be suppressed.

[0116] The second gap G2 is 1.2 times or more the first gap G1. With this configuration, the vibration damping of the light-transmitting body 10 is further improved. Suppress It is possible.

[0117] When viewed in 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 recess 11 of the light-transmitting body 10. With this configuration, it is possible to suppress vibration damping of the light-transmitting body 10 while improving the optical characteristics.

[0118] The curvature of the first portion 51a of the inner layer lens 51 is greater than the curvature of the recess 11 of the light-transmitting body 10. With this configuration, sound waves reflected by the first portion 51a are more likely to be diffused. This makes it possible to further suppress the concentration of sound pressure in the gap G0, and thus to further suppress vibration attenuation.

[0119] The second portion 51b has a flat surface FS1 perpendicular to the thickness direction (Z direction) of the inner layer lens 51. 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 on the inside of the lens holding portion 52. With this configuration, the inner layer lens 51 can be stably held by the pressing portion 52a of the lens holding portion 52 while suppressing the concentration of sound pressure in the second portion 51b. This prevents the inner layer lens 51 from falling off and suppresses positional deviation, thereby maintaining the optical path.

[0120] The inner layer lens 51 is composed of a spherical lens or an aspherical lens. With such a configuration, the inner layer lens 51 having the first portion 51a and the second portion 51b can be easily produced.

[0121] The recess 11 of the transparent body 10 has a hemispherical recessed shape. With this configuration, the sound waves can be diffused when reflected at the recess 11 of the transparent body 10. This makes it possible to suppress concentration of sound pressure in the gap G0 and suppress vibration attenuation.

[0122] The optical device 100 includes an optical module 1 and an optical element 2 disposed in the optical module 1. With such a configuration, it is possible to achieve the same effects as the optical module 1 described above.

[0123] <Variation 1> Fig. 10 is a schematic cross-sectional view showing the main configuration of an optical module 1A of modified example 1. As shown in Fig. 10, the second portion 51ba of the inner layer lens 51A may have an inclined surface FS2 that is inclined in a direction away from the light-transmitting body 10 toward the outer periphery of the inner layer lens 51A. The inclined surface FS2 is inclined so that the second gap G2 continuously increases toward the radial outside of the inner layer lens 51A. The inner layer lens 51A may be composed of, for example, an aspheric lens.

[0124] Even in such a configuration, the second gap G2 can be made larger than the first gap G1, so that the concentration of sound pressure in the gap G0 can be suppressed, and the vibration damping of the light-transmitting body 10 can be suppressed.

[0125] <Variation 2> Fig. 11 is a schematic cross-sectional view showing the main configuration of an optical module 1B of modified example 2. As shown in Fig. 11, a first portion 51a of an inner layer lens 51 may be disposed in a recess 11A of a light-transmitting body 10A. In addition, a curvature of the recess 11A may be larger than a curvature of the first portion 51a of the inner layer lens 51.

[0126] With this configuration, the light-transmitting body 10 and the inner layer lens 51 can be arranged closer to each other, thereby making it possible to miniaturize the optical module 1. Even if the gap G0 is small because the light-transmitting body 10 and the inner layer lens 51 are arranged closer to each other in this way, the second gap G2 is made larger than the first gap G1, making it possible to easily emit sound waves from within the gap G0. This makes it possible to miniaturize the optical module 1B while suppressing the concentration of sound pressure within the gap G0 and suppressing vibration damping of the light-transmitting body 10.

[0127] <Modification 3> Fig. 12 is a schematic cross-sectional view showing the main configuration of an optical device 100A of Modification 3. As shown in Fig. 12, in an optical module 1C in the optical device 100A, a curved portion R1 is provided at a corner of a 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 rounded curved shape.

[0128] By providing the curved portion R1 at the corner of the vibrating body 20A, it is possible to disperse stress when the vibrating body 20A vibrates. This reduces stress, thereby suppressing fatigue damage of the vibrating body 20A and improving reliability.

[0129] In the present embodiment, the second portion 51b is configured as a step or an inclined surface, but is not limited thereto. The second portion 51b may be formed so that the second gap G2 is larger than the first gap G1. For example, the second portion 51b may be configured as a curved surface that is curved in a direction away from the light-transmitting body 10. The curved surface is, for example, a surface having a curvature.

[0130] Although the present invention has been fully described in connection with the preferred embodiment with reference to the accompanying drawings, various changes and modifications will become apparent to those skilled in the art, and such changes and modifications are to be understood as being included within the scope of the present invention as defined by the appended claims, unless they depart therefrom. [Industrial Applicability]

[0131] The vibration device and vibration control method of the present invention can be applied to vehicle-mounted cameras, surveillance cameras, or optical sensors such as LiDAR used outdoors. [Explanation of symbols]

[0132] 1,1A,1B,1C Optical Module 2. Optical elements 3. Control Unit 10,10A Translucent body 11,11A Recess 20,20A Vibration Body 21 Vibration flange 22 First cylindrical body 23 Spring section 24 Second cylindrical body 25 Diaphragm 26 Connection 30 Piezoelectric element 40 Fixed part 50 Inner layer optical components 51,51A Inner layer lens 51a Part 1 51b,51ba 2nd part 52 Lens holder 52a Holding part 52b Contact part 53 Inner layer flange 100,100A optical device A1 Vibration direction C1 center D11, D12, D21, D22 Outer diameter FS1 Flat Surface FS2 Slope G0 Gap G1 First Gap G2 2nd Gap PS1 First main surface PS2 2nd main surface

Claims

1. A transparent body; A vibrating body formed in a cylindrical shape and supporting the light-transmitting body; A piezoelectric element is disposed on the vibrating body and vibrates the vibrating body; An inner layer optical component disposed inside the vibrating body; Equipped with A concave portion having a curvature and recessed in a thickness direction of the light-transmitting body is formed on a surface of the light-transmitting body facing the inner layer optical component, The inner layer optical component includes an inner layer lens facing the light-transmitting body, The inner layer lens includes a first portion that protrudes toward the light-transmitting body and has a curvature, and a second portion that is provided on an outer periphery of the first portion, a first gap is formed between the first portion and the light-transmitting body at the outer periphery of the first portion, A second gap is formed between the second portion and the light-transmitting body, The second gap is larger than the first gap. Optical module.

2. The second portion is a step recessed in a direction away from the light-transmitting body from the first portion. The optical module according to claim 1 .

3. The second portion has an inclined surface that is inclined in a direction away from the light-transmitting body toward the outer periphery of the inner layer lens. The optical module according to claim 1 .

4. The second gap is 1.2 times or more the first gap. The optical module according to claim 1 .

5. When viewed in the thickness direction of the light-transmitting body, the outer diameter of the inner layer lens is larger than the outer diameter of the recess of the light-transmitting body. The optical module according to claim 1 .

6. The curvature of the first portion of the inner layer lens is greater than the curvature of the concave portion of the transparent body. The optical module according to claim 1 .

7. The second portion has a flat surface perpendicular to a thickness direction of the inner layer lens, The inner layer optical component includes a cylindrical lens holding portion that stores the inner layer lens, The lens holder has a pressing portion that is in contact with the flat surface on the inside of the lens holder. The optical module according to claim 1 .

8. The first portion is disposed within the recess of the optically transparent body. The optical module according to claim 1 .

9. The inner layer lens is composed of a spherical lens or an aspherical lens. The optical module according to claim 1 .

10. The recess of the transparent body has a hemispherical recessed shape. The optical module according to claim 1 .

11. An optical module according to any one of claims 1 to 10; an optical element disposed in the optical module; An optical device comprising:

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