Sensor device

Abstract

This sensor device comprises: an externally facing exposed portion; and a vibration source capable of causing the exposed portion to vibrate. The exposed portion has a maximum displacement portion, of which a displacement amount due to the vibration of the vibration source is the highest, and a minimum displacement portion, of which the displacement amount due to the vibration source is the lowest. The maximum displacement portion and the minimum displacement portion are located at opposing positions with respect to the centre of the exposed portion. The exposed portion has a displacement slope ratio, defined by formula (1): (A-B) / L [in formula (1), A is a maximum displacement amount (μm) representing the displacement amount of the maximum displacement portion, B is a minimum displacement amount (μm) representing the displacement amount of the minimum displacement portion, and L is the distance (mm) between the maximum displacement portion and the minimum displacement portion. The displacement slope ratio is also defined by formula (2): C ≥ 2.3935e-0.176B [in formula (2), C is the displacement slope ratio, B is the minimum displacement amount, and e is Euler's number].

Description

Sensor Device

[0001] The present disclosure relates to a sensor device.

[0002] Patent Document 1 discloses a droplet removal device that has the function of reliably and efficiently removing droplets and the like that have adhered to the light beam passing area of ​​a dome-shaped drip-proof cover.

[0003] Japanese Patent Application Laid-Open No. 2017-170303

[0004] The droplet removal device of Patent Document 1 has room for improvement in terms of more reliably removing foreign matter adhering to the dome-shaped drip-proof cover.

[0005] An object of the present disclosure is to provide a sensor device that can more reliably remove foreign matter adhering to an exposed portion.

[0006] A sensor device according to a first aspect of the present disclosure includes an exposed portion facing the outside, and a vibration source capable of vibrating the exposed portion, wherein the exposed portion has a maximum displacement portion where a displacement amount due to vibration of the vibration source is maximum, and a minimum displacement portion where a displacement amount due to the vibration source is minimum, the maximum displacement portion and the minimum displacement portion are located at positions opposite each other with respect to a center of the exposed portion, and the exposed portion has a displacement gradient rate defined by the following formula (1): (A-B) / L formula (1) [in formula (1), A is the maximum displacement amount (μm) that is the displacement amount of the maximum displacement portion, B is the minimum displacement amount (μm) that is the displacement amount of the minimum displacement portion, and L is the distance (mm) between the maximum displacement portion and the minimum displacement portion], and the displacement gradient rate satisfies the following formula (2): C≧2.3935e －０．１７６Ｂ It is defined by the formula (2): [In the formula (2), C is the displacement gradient rate, B is the minimum displacement amount, and e is Napier's constant].

[0007] A sensor device according to a second aspect of the present disclosure includes an exposed portion facing the outside, and a vibration source capable of vibrating the exposed portion, wherein the exposed portion has a maximum displacement portion where a displacement amount due to vibration of the vibration source is maximum, and a minimum displacement portion where a displacement amount due to the vibration source is minimum, the maximum displacement portion and the minimum displacement portion are located at positions opposite to each other with respect to the center of the exposed portion, and the exposed portion has a displacement gradient defined by the following formula (1): (A-B) / L formula (1) [in formula (1), A is the maximum displacement amount (μm) that is the displacement amount of the maximum displacement portion, B is the minimum displacement amount (μm) that is the displacement amount of the minimum displacement portion, and L is the distance (mm) between the maximum displacement portion and the minimum displacement portion], and the displacement gradient rate satisfies the following formula (3): C≧3.6203e －０．１３２Ｂ It is defined by the following equation (3): [In equation (3), C is the displacement gradient rate, B is the minimum displacement amount, and e is Napier's constant].

[0008] According to the present disclosure, a sensor device can be provided that can more reliably remove foreign matter adhering to an exposed portion.

[0009] 9 is a perspective view showing a sensor device according to an example of the present disclosure; FIG. 1 is a cross-sectional view taken along line II-II of FIG. 1; FIG. 2 is a perspective view showing the sensor device of FIG. 1 in a state in which the minimum displacement portion is positioned vertically above the maximum displacement portion; FIG. 3 is a graph showing the relationship between the displacement gradient rate and the minimum displacement amount and the results of removing foreign matter of 1 μL or more; FIG. 4 is a diagram showing a foreign matter 100 of 1 μL or more; FIG. 5 is a graph showing the relationship between the displacement gradient rate and the minimum displacement amount and the results of removing foreign matter of 1 μL or less; FIG. 6 is a diagram showing a foreign matter 110 of 1 μL or less; FIG. 7 is a displacement contour diagram of the sensor device of FIG. 1; FIG. 8 is a stress contour diagram of the sensor device of FIG. 1 corresponding to FIG. 8; FIG. 9 is a partial enlarged view of FIG. 1; FIG. 10 is a graph showing the relationship between the stress applied to the sensor device of FIG. 1 and the maximum displacement amount of the lens; FIG. 11 is a graph showing the relationship between the maximum and minimum displacement amounts of the lens, the displacement gradient rate, and the failure range of the sensor device of FIG. 1; FIG. 12 is a graph showing the relationship between the displacement gradient rate and the maximum displacement amount and the failure range of the sensor device of FIG. 1, corresponding to the graph of FIG. 6; FIG. 13 is a cross-sectional view showing a modified example of the external vibrator of the sensor device of FIG. 1; A plan view showing a first modified example of the external vibrator of Fig. 14. A plan view showing a second modified example of the external vibrator of Fig. 14. A sectional view taken along line XVII-XVII of Fig. 14 showing the second modified example of the external vibrator of Fig. 14. A plan view showing the second modified example of the external vibrator of Fig. 14.

[0010] Various aspects of the present disclosure will now be described.

[0011] A sensor device according to a first aspect of the present disclosure includes an exposed portion facing the outside, and a vibration source capable of vibrating the exposed portion, wherein the exposed portion has a maximum displacement portion where a displacement amount due to vibration of the vibration source is maximum, and a minimum displacement portion where a displacement amount due to the vibration source is minimum, the maximum displacement portion and the minimum displacement portion are located at positions opposite each other with respect to a center of the exposed portion, and the exposed portion has a displacement gradient rate defined by the following formula (1): (A-B) / L formula (1) [in formula (1), A is the maximum displacement amount (μm) that is the displacement amount of the maximum displacement portion, B is the minimum displacement amount (μm) that is the displacement amount of the minimum displacement portion, and L is the distance (mm) between the maximum displacement portion and the minimum displacement portion], and the displacement gradient rate satisfies the following formula (2): C≧2.3935e －０．１７６ＢIt is defined by the formula (2): [In the formula (2), C is the displacement gradient rate, B is the minimum displacement amount, and e is Napier's constant].

[0012] A sensor device according to a second aspect of the present disclosure includes an exposed portion facing the outside, and a vibration source capable of vibrating the exposed portion, wherein the exposed portion has a maximum displacement portion where a displacement amount due to vibration of the vibration source is maximum, and a minimum displacement portion where a displacement amount due to the vibration source is minimum, the maximum displacement portion and the minimum displacement portion are located at positions opposite to each other with respect to the center of the exposed portion, and the exposed portion has a displacement gradient defined by the following formula (1): (A-B) / L formula (1) [in formula (1), A is the maximum displacement amount (μm) that is the displacement amount of the maximum displacement portion, B is the minimum displacement amount (μm) that is the displacement amount of the minimum displacement portion, and L is the distance (mm) between the maximum displacement portion and the minimum displacement portion], and the displacement gradient rate satisfies the following formula (3): C≧3.6203e －０．１３２Ｂ It is defined by the following equation (3): [In equation (3), C is the displacement gradient rate, B is the minimum displacement amount, and e is Napier's constant].

[0013] A sensor device according to a third aspect of the present disclosure is the sensor device according to the second aspect, wherein the displacement gradient rate is expressed by the following formula (4): C≧3.2337e －０．０９３Ｂ It is defined by the following equation (4): [In equation (4), C is the displacement gradient rate, B is the minimum displacement amount, and e is Napier's constant].

[0014] A sensor device according to a fourth aspect of the present disclosure is the sensor device according to the second aspect, wherein the minimum displacement is 15 μm or more, and the displacement gradient rate is 1.0 μm / mm or more.

[0015] A sensor device according to a fifth aspect of the present disclosure is the sensor device according to any one of the first to fourth aspects, wherein the minimum displacement portion is positioned vertically above the maximum displacement portion.

[0016] A sensor device according to a sixth aspect of the present disclosure is the sensor device according to any one of the first to fifth aspects, wherein the exposed portion has an exposed surface that is water-repellent.

[0017] An example of the present disclosure will be described below with reference to the accompanying drawings. The following description is merely exemplary in nature and does not limit the present disclosure, its applications, and uses. The accompanying drawings are schematic drawings, and the illustrated configuration and actual products may differ in dimensional ratios, etc.

[0018] As shown in FIGS. 1 and 2 , a sensor device 1 according to an example of the present disclosure includes a lens 5 (an example of an exposed portion) and a vibration source 9. The lens 5 has an optical axis L (an example of a center of the exposed portion) extending along a first direction (e.g., the Z direction). In this embodiment, the lens 5 has a water-repellent exposed surface 51. The exposed surface 51 faces the outside of the sensor device 1 in a state where foreign matter (e.g., pure water) can adhere to it. The vibration source 9 is configured to be able to vibrate the lens 5. The vibration source 9 includes, for example, an element (a piezoelectric element, an electromagnetic vibrator, a magnetostrictive vibrator, etc.) or an actuator (an SMA actuator, an electromagnetic actuator, a motor, etc.).

[0019] The sensor device 1 includes an internal vibrator 7 and an external vibrator 3. A vibration source 9 is connected to one end of the internal vibrator 7 in the first direction Z. A lens 5 is connected to the other end of the internal vibrator 7 in the first direction Z. Vibrations generated by the vibration source 9 are transmitted to the lens 5 via the internal vibrator 7, causing the lens 5 to vibrate. This removes foreign matter such as water droplets or mud adhering to the lens 5.

[0020] The internal vibrator 7 is configured to be able to amplify vibrations generated by the vibration source 9. The internal vibrator 7 includes, for example, a metal material such as stainless steel, aluminum, iron, titanium, or duralumin, or ceramics. The surface of the internal vibrator 7 may be subjected to a surface treatment such as oxidation or alumite treatment to improve adhesive adhesion. For example, by blackening the surface of the internal vibrator 7 through surface treatment, it is possible to prevent degradation of optical performance due to diffuse reflection of light.

[0021] The internal vibrator 7 is, for example, a cylindrical body positioned symmetrically with respect to the optical axis L. The internal vibrator 7 includes a first portion 71 in contact with the lens 5, a second portion 72 to which the vibration source 9 is attached, and a third portion 73 connecting the first portion 71 and the second portion 72. The first portion 71 and the second portion 72 have, for example, a cylindrical shape extending along the first direction Z. The second portion 72 is configured to vibrate together with the vibration of the vibration source 9 and has a thickness (i.e., a dimension in the first direction Z) greater than those of the first portion 71 and the third portion 73. This facilitates more efficient transmission of the vibration of the vibration source 9 to the lens 5. The third portion 73 has a substantially S-shaped cross section and is configured to support the first portion 71 and transmit the vibration of the second portion 72 to the first portion 71.

[0022] The first portion 71, the second portion 72, and the third portion 73 may be formed integrally or separately. The maximum outer dimension of the third portion 73 (i.e., the maximum dimension in a second direction (e.g., the X direction) intersecting the first direction Z) is larger than the maximum outer dimension of the first portion 71, and the maximum outer dimension of the second portion 72 is larger than the maximum outer dimension of the third portion 73. This allows the vibration of the vibration source 9 to be efficiently transmitted to the lens 5.

[0023] The external vibrator 3 is configured to prevent the vibrations of the internal vibrator 7 from escaping to members other than the lens 5 and to efficiently transmit the vibrations of the internal vibrator 7 to the lens 5. As an example, the external vibrator 3 is configured to cover the entire internal vibrator 7 and protect the internal vibrator 7 from the outside. The external vibrator 3 includes, for example, a metal material such as stainless steel, aluminum, iron, titanium, or duralumin, or a resin.

[0024] As an example, the external vibrator 3 has a substantially rectangular prism shape and is configured to surround the internal vibrator 7 in a radial direction (e.g., the X direction) relative to the optical axis L. The external vibrator 3 of this embodiment includes a first connecting portion 31, a cylinder portion 32, an attenuator portion 33, a second connecting portion 34, and a fixing portion 35.

[0025] The first connecting portion 31 has, for example, a cylindrical shape extending in the first direction Z. A radially inner surface of the first connecting portion 31 relative to the optical axis L is in contact with a radially outer surface of the internal vibrator 7 relative to the optical axis L. In other words, the first connecting portion 31 is connected to the lens 5 via the internal vibrator 7. The first connecting portion 31 is not limited to being connected to the lens 5 via the internal vibrator 7, and may also be connected to the lens 5 without the internal vibrator 7 via, for example, an adhesive.

[0026] The outer surface of the first connection portion 31 is covered with a cover member 8. The cover member 8 includes, for example, a resin member or a metal member, and is configured to cover the first connection portion 31 and the outer end of the lens 5 in the radial direction with respect to the optical axis L. The cover member 8 more reliably connects the first connection portion 31 and the lens 5, and also prevents moisture and foreign matter on the lens 5 from entering the interior of the external vibrator 3.

[0027] The cylinder portion 32 extends from the first connection portion 31 in the first direction Z in a direction away from the lens 5, and connects the first connection portion 31 and the attenuator portion 33. The cylinder portion 32 has, for example, a cylindrical shape and is configured to have an inner diameter larger than that of the first connection portion 31. A step is formed between the first connection portion 31 and the cylinder portion 32, and a gap is formed between the cylinder portion 32 and the internal vibrator 7. The cylinder portion 32 may include an inclined portion whose diameter gradually increases as it approaches the attenuator portion 33.

[0028] The attenuator section 33 extends from one of the ends of the cylinder section 32 in the first direction Z that is farthest from the lens 5 toward the outside in the radial direction with respect to the optical axis L. The attenuator section 33 has spring characteristics and is configured to attenuate vibrations generated by the vibration source 9.

[0029] The second connecting portion 34 extends from one of the ends of the attenuator portion 33 in the radial direction relative to the optical axis L, the end farthest from the optical axis L, in a direction away from the lens 5 along the first direction Z, and connects the attenuator portion 33 and the fixed portion 35. The second connecting portion 34 is, for example, cylindrical and configured to have spring characteristics.

[0030] The fixing portion 35 extends from one of the ends of the second connection portion 34 in the first direction Z that is farthest from the attenuator portion 33 in a direction away from the lens 5 along the first direction Z. The fixing portion 35 is configured to be able to suppress vibrations propagated to members connected to the fixing portion 35 (for example, a case that houses the imaging element and a lens module). The fixing portion 35 is configured to have a thickness (i.e., a radial dimension relative to the optical axis L) that is greater than other portions of the external vibrator 3.

[0031] 1, the fixed portion 35 has a substantially rectangular prism-like outer shape. By configuring it in this manner, the volume of the fixed portion 35 can be increased without increasing the size of the sensor device 1.

[0032] The maximum width of the first connecting portion 31 in the radial direction relative to the optical axis L (hereinafter referred to as the maximum outer dimension) is smaller than the maximum outer dimension of the cylinder portion 32, which is smaller than the maximum outer dimension of the attenuator portion 33. The maximum outer dimensions of the attenuator portion 33 and the second connecting portion 34 are substantially the same and are smaller than the maximum outer dimension of the fixed portion 35. With this configuration, the portion of the external vibrator 3 located on the lens 5 side can vibrate more easily, while vibration of the fixed portion 35 can be suppressed.

[0033] In this embodiment, the external vibrator 3 is made of a material having a lower Young's modulus than the internal vibrator 7. By configuring it in this way, the attenuation of vibration by the attenuator section 33 can be increased.

[0034] The first connecting portion 31, the cylinder portion 32, the attenuator portion 33, the second connecting portion 34, and the fixed portion 35 may be integrally formed as a single member, or may be individually formed as different members. The first connecting portion 31, the cylinder portion 32, the attenuator portion 33, and the second connecting portion 34 may be integrally formed as a single member, and only the fixed portion 35 may be individually formed as a separate member.

[0035] The sensor device 1 is configured so that the lens 5 has a maximum displacement portion P1 and a minimum displacement portion P2 and has a displacement gradient rate defined by the following formula 1 and formula 2, or has a displacement gradient rate defined by the following formula 1 and formula 3, or formula 4. In formula 1, A is the maximum displacement amount (μm) that is the displacement amount of the maximum displacement portion P1, B is the minimum displacement amount (μm) that is the displacement amount of the minimum displacement portion P2, and L is the distance (mm) between the maximum displacement portion P1 and the minimum displacement portion P2. L is calculated, for example, from the difference in coordinates (e.g., XYZ coordinates) assigned to the maximum displacement portion P1 and the minimum displacement portion P2. In formulas 2 to 4, C is the displacement gradient rate, B is the minimum displacement amount, and e is Napier's constant.

[0036] The maximum displacement portion P1 is a portion of the lens 5 where the amount of displacement caused by the vibration of the vibration source 9 is the largest, and the minimum displacement portion P2 is a portion of the lens 5 where the amount of displacement caused by the vibration of the vibration source 9 is the smallest. As shown in Figures 2 and 3, the maximum displacement portion P1 and the minimum displacement portion P2 are located at positions opposite each other with respect to the optical axis L. Figure 3 shows the sensor device 1 in a state where the minimum displacement portion P2 is located vertically above the maximum displacement portion P1.

[0037] 4 shows the relationship between the displacement gradient rate C and the minimum displacement amount B and the result of removing foreign matter of 1 μL or more. FIG. 5 shows an example of a foreign matter 100 of 1 μL or more. The dotted line R1 in FIG. 4 indicates the relationship between C=2.3935e －０．１７６Ｂ 4 is an approximation curve of the above. A circle (●) indicates a result in which the foreign matter 100 was successfully removed. A cross (×) indicates a result in which the foreign matter 100 was not successfully removed. In FIG. 4, the displacement of the lens 5 was measured in a room temperature (25±5 degrees Celsius) environment using a laser Doppler displacement meter (LV1800 manufactured by Ono Keisokuki) and a gain phase analyzer (FRA51602 manufactured by NF Corporation).

[0038] As shown in FIG. 4, the area on the dotted line R1 and the area to the upper right of the dotted line R1 (C≧2.3935e －０．１７６Ｂ ), only circles are shown, while the area below and to the left of the dotted line R1 (C<2.3935e－０．１７６Ｂ ) has multiple crosses. In other words, it has been found that by configuring the sensor device 1 so that the lens 5 has a displacement gradient rate defined by the mathematical expressions 1 and 2, foreign matter 100 of 1 μL or more can be more reliably removed.

[0039] 6 shows the relationship between the displacement gradient rate C and the minimum displacement amount B and the result of removing foreign matter of 1 μL or less. FIG. 7 shows an example of a foreign matter 110 of 1 μL or less. The dotted line R2 in FIG. 6 corresponds to C=3.6203 e －０．１３２Ｂ The dotted line R3 is an approximate curve of 3.2337e －０．０９３Ｂ 6 is an approximation curve of the above. Circles (●) indicate results in which the foreign matter 110 was removed quickly (for example, within 10 seconds). Triangles (▲) indicate results in which the foreign matter 110 was removed but not quickly. Crosses (×) indicate results in which the foreign matter was not removed. In FIG. 6, the displacement of the lens 5 was measured in a room temperature (25±5°C) environment using a laser Doppler displacement meter (LV1800 manufactured by Ono Keisokuki) and a gain phase analyzer (FRA51602 manufactured by NF Corporation).

[0040] As shown in FIG. 6, the area on the dotted line R2 and the area to the upper right of the dotted line R2 (C≧3.6203e －０．１３２Ｂ ), only circles and triangles are shown, while the area below and to the left of the dotted line R2 (C<3.6203e －０．１３２Ｂ ) has multiple crosses. In other words, it has been found that the sensor device 1 (hereinafter referred to as the first sensor device 1) including the lens 5 configured to have the displacement gradient rate defined by the mathematical expressions 1 and 3 can more reliably remove foreign matter 110 of 1 μL or less.

[0041] The area above the dotted line R3 and the area to the upper right of the dotted line R3 (C≧3.2337e －０．０９３Ｂ ) shows only a circle. That is, it was found that the sensor device 1 (hereinafter referred to as the second sensor device 1) including the lens 5 configured to have the displacement gradient rate defined by the mathematical expressions 1 and 4 can remove foreign matter 110 of 1 μL or less more reliably and quickly (for example, within 10 seconds) than the first sensor device 1.

[0042] It was found that, for the same minimum displacement amount B, the removal speed of the foreign matter 110 increases as the displacement gradient rate C increases. The removal speed of the foreign matter 110 was fastest when the displacement gradient rate C and the minimum displacement amount B were within the range of the first region 201, followed by when the displacement gradient rate C and the minimum displacement amount B were within the range of the second region 202, and slowest when the displacement gradient rate C and the minimum displacement amount B were within the range of the third region 203. In other words, it was found that the second sensor device 1 can sometimes remove foreign matter 110 of 1 μL or less faster than the first sensor device 1. For example, when the displacement gradient rate C and the minimum displacement amount B were within the range of the first region 201, removal of the foreign matter 110 was sometimes completed within one second. On the other hand, when the displacement gradient rate C and the minimum displacement amount B were within the range of the third region 203, it sometimes took 10 seconds to complete removal of the foreign matter 110.

[0043] For example, let us assume that the sensor device 1 includes a lens 5 configured to have a displacement gradient C and a minimum displacement B within the range of the region 200 shown by the dashed line in Fig. 6 (i.e., the minimum displacement B is 15 μm or more and the displacement gradient C is 1.0 μm / mm or more). It has been found that the sensor device 1 in this case can sometimes remove foreign matter 110 of 1 μL or less more quickly than the second sensor device 1.

[0044] FIG. 8 shows an example of a displacement contour diagram of the sensor device 1, and FIG. 9 shows an example of a stress contour diagram of the sensor device 1 corresponding to FIG. 8. FIG. 10 is an enlarged view showing the lens 5 portion of the stress contour diagram of FIG. 9. FIG. 11 shows an example of the relationship between the stress applied to the sensor device 1 and the maximum displacement amount A of the lens 5. As shown in FIGS. 8 to 10, the stress applied to the sensor device 1 tends to concentrate at the maximum displacement point P1. As shown in FIG. 11, as the maximum displacement amount A of the lens 5 increases, the stress applied to the sensor device 1 also increases. Therefore, the upper limit of the displacement amount of the lens 5 (i.e., the upper limit of the maximum displacement amount A) is determined from the stress value within the range in which the sensor device 1 will not break.

[0045] 12 shows an example of the relationship between the maximum displacement amount A and minimum displacement amount B of the lens 5, the displacement gradient rate C, and the failure range 300 of the sensor device 1. In the example of FIG. 12, when the maximum displacement amount A of the lens 5 exceeds 35 μm, the sensor device 1 tends to fail. The displacement gradient rate C is set within a range that does not fall within the failure range 300.

[0046] 13 shows an example of the relationship between the displacement gradient rate C and the maximum displacement amount A corresponding to the graph in Fig. 6 and the failure range 300 of the sensor device 1. As shown in Fig. 13, the smaller the maximum displacement amount A, the smaller the failure risk of the sensor device 1.

[0047] The sensor device 1 can be realized, for example, by the following configuration.

[0048] The sensor device 1 includes an attenuator unit 33 that is asymmetrical with respect to the optical axis L. The asymmetrical nature of the attenuator unit 33 can be achieved, for example, in the following manner: The attenuator unit 33 includes a first attenuator unit 331 and a second attenuator unit 332 that are positioned symmetrically with respect to the optical axis L. The first attenuator unit 331 and the second attenuator unit 332 are formed of different materials. For example, the first attenuator unit 331 is formed of a material having a smaller Young's modulus than the second attenuator unit 332. The first attenuator unit 331 and the second attenuator unit 332 may be formed of materials that are not limited to having a different Young's modulus, but may also have a different density or mechanical Q value, for example. The first attenuator unit 331 and the second attenuator unit 332 are formed so that their dimensions in the first direction Z (i.e., the thickness dimension of the attenuator unit 33) are different. For example, in the external vibrator 3 shown in Fig. 14 , the first attenuator section 331 has a thin portion 3311 having the same thickness (= t2) as the second attenuator section 332, and a thick portion 3312 having a thickness (= t1) greater than that of the thin portion 3311. The first attenuator section 331 may be configured as shown in Figs. 15 and 16 . In the first attenuator section 331 of Fig. 15 , the thick portion 3312 has a crescent shape extending toward the second attenuator section 332 along the outer shape of the external vibrator 3 when viewed along the direction of arrow XV in Fig. 14 . In the first attenuator section 331 of Fig. 16 , the thick portion 3312 has a straight portion facing the optical axis L and an arc portion extending along the outer shape of the external vibrator 3 when viewed along the direction of arrow XV in Fig. 14 . The first attenuator section 331 and the second attenuator section 332 are formed so that their lengths u (see FIG. 14) in the radial direction relative to the optical axis L are different.

[0049] The sensor device 1 includes a cylinder portion 32 that is non-axially symmetric with respect to the optical axis L. The non-axial symmetry of the cylinder portion 32 can be achieved, for example, in the following manner: The cylinder portion 32 includes a first cylinder portion 321 and a second cylinder portion 322 that are positioned symmetrically with respect to the optical axis L. The first cylinder portion 321 and the second cylinder portion 322 are formed of different materials. For example, the first attenuator portion 331 is formed of a material having a smaller Young's modulus than the second attenuator portion 332. The first cylinder portion 321 and the second cylinder portion 322 may be formed of materials that are not limited to having a different Young's modulus, but may also have a different density or mechanical Q value, for example. The first cylinder portion 321 and the second cylinder portion 322 are formed so that their radial dimensions with respect to the optical axis L (i.e., the thickness dimension of the cylinder portion 32) are different. For example, in the external vibrator 3 shown in FIGS. 14 and 17 , the second cylinder portion 322 has a thickness s2 that is greater than the thickness s1 of the first cylinder portion 321. In the external vibrator 3 shown in FIG. 18, the first cylinder portion 321 and the second cylinder portion 322 are formed to have the same thickness s1, and a weight member 325 is fixed to the second cylinder portion 322.

[0050] 14, both the cylinder portion 32 and the attenuator portion 33 are non-axially symmetric, but this is not limiting. The external vibrator 3 may be configured so that only one of the cylinder portion 32 and the attenuator portion 33 is non-axially symmetric.

[0051] The sensor device 1 can achieve the following effects.

[0052] The sensor device 1 includes a lens 5 having an optical axis L, and a vibration source 9 capable of vibrating the lens 5. The lens 5 has a maximum displacement portion P1 where the amount of displacement due to vibration of the vibration source 9 is maximum, and a minimum displacement portion P2 where the amount of displacement due to vibration of the vibration source 9 is minimum. The maximum displacement portion P1 and the minimum displacement portion P2 are located at positions opposite each other with respect to the optical axis L. The lens 5 has a displacement gradient defined by the following formula (1): (A-B) / L formula (1) [In formula (1), A is the maximum displacement amount (μm) that is the displacement amount of the maximum displacement portion P1, B is the minimum displacement amount (μm) that is the displacement amount of the minimum displacement portion P2, and L is the distance (mm) between the maximum displacement portion P1 and the minimum displacement portion P2]. When the displacement gradient is such that C≧2.3935e, the following formula (2) is satisfied: －０．１７６Ｂ It is defined by the formula (2) [in formula (2), C is the displacement gradient rate, B is the minimum displacement amount, and e is Napier's constant]. With this configuration, it is possible to provide a gradient to the vibration displacement of the lens 5, thereby preventing foreign matter from concentrating at the center of the lens 5 and facilitating the removal of foreign matter. For example, foreign matter of 1 μL or more can be more reliably removed in a room temperature environment.

[0053] The sensor device 1 includes a lens 5 having an optical axis L, and a vibration source 9 capable of vibrating the lens 5. The lens 5 has a maximum displacement portion P1 where the amount of displacement due to vibration of the vibration source 9 is maximum, and a minimum displacement portion P2 where the amount of displacement due to vibration of the vibration source 9 is minimum. The maximum displacement portion P1 and the minimum displacement portion P2 are located at positions opposite each other with respect to the optical axis L. The lens 5 has a displacement gradient defined by the following formula (1): (A-B) / L formula (1) [In formula (1), A is the maximum displacement amount (μm) that is the displacement amount of the maximum displacement portion P1, B is the minimum displacement amount (μm) that is the displacement amount of the minimum displacement portion P2, and L is the distance (mm) between the maximum displacement portion P1 and the minimum displacement portion P2]. When the displacement gradient is such that the following formula (3): C≧3.6203e －０．１３２ＢIt is defined by Equation (3) [In Equation (3), C is the displacement gradient rate, B is the minimum displacement amount, and e is Napier's constant]. With this configuration, it is possible to provide a gradient to the vibration displacement of the lens 5, thereby preventing foreign matter from concentrating at the center of the lens 5 and facilitating the removal of foreign matter. For example, foreign matter of 1 μL or less can be more reliably removed in a room temperature environment.

[0054] The displacement gradient rate is expressed by the following formula (4): C≧3.2337e －０．０９３Ｂ It is defined by the following formula (4): [In formula (4), C is the displacement gradient rate, B is the minimum displacement amount, and e is Napier's number] With this configuration, for example, foreign matter of 1 μL or less can be removed more reliably and quickly (for example, within 10 seconds) in a room temperature environment.

[0055] The minimum displacement amount B is 15 μm or more, and the displacement gradient rate C is 1.0 μm / mm or more. With this configuration, foreign matter of 1 μL or less can be removed more reliably and more quickly (for example, within 1 second) in a room temperature environment.

[0056] The minimum displacement portion P2 is located vertically above the maximum displacement portion P1. With this configuration, the removal of foreign matter from the lens 5 can be facilitated.

[0057] The lens 5 has a water-repellent exposed surface 51. With this configuration, removal of foreign matter from the lens 5 can be facilitated.

[0058] The sensor device 1 can be configured as follows.

[0059] The exposed portion is not limited to the lens 5, but may be another light-transmitting body, or may be a flat plate or metal plate that does not have light-transmitting properties.

[0060] The internal vibrator 7 and the vibration source 9 may or may not be positioned symmetrically with respect to the optical axis L.

[0061] The cylinder portion 32 and / or the attenuator portion 33 are not limited to the above-described embodiment, and any configuration that can achieve non-axisymmetricity can be adopted. For example, the cylinder portion 32 and / or the attenuator portion 33 having non-axisymmetricity may be achieved by fixing a separate member to the cylinder portion 32 and / or the attenuator portion 33.

[0062] The sensor device 1 can be used in any manner. For example, the sensor device 1 can be used in a state where the minimum displacement portion P2 is located vertically lower than the maximum displacement portion P1, or in a state where the maximum displacement portion P1 and the minimum displacement portion P2 are located at the same position in the vertical direction.

[0063] The exposed surface 51 of the lens 5 does not need to be water-repellent.

[0064] The present disclosure is not limited to the sensor device 1 of the above embodiment, but can also be applied to other embodiments of the sensor device 1 that include an exposed portion and a vibration source 9 capable of vibrating the exposed portion, and are configured so that the exposed portion has a displacement gradient rate defined by Formula 1 and Formula 2, or so that the exposed portion has a displacement gradient rate defined by Formula 1 and Formula 3 or Formula 4.

[0065] The embodiments and modifications of the present disclosure can be combined with each other, or with modifications, or with each other. Features included in the embodiments and modifications of the present disclosure can also be combined with each other.

[0066] The disclosure of the present disclosure may vary in structural details, and changes in the combination and order of elements in each embodiment may be made without departing from the scope and spirit of the claimed disclosure.

[0067] REFERENCE SIGNS LIST 1 Sensor device 3 External vibrator 5 Lens 7 Internal vibrator 71 First part 72 Second part 73 Third part 8 Cover member 9 Vibration source 31 First connection part 32 Cylinder part 321 First cylinder part 322 Second cylinder part 325 Weight member 33 Attenuator part 331 First attenuator part 3311 Thin part 3312 Thick part 332 Second attenuator part 34 Second connection part 35 Fixing part 51 Exposed surface 100, 110 Foreign matter 200, 201, 202, 203 Area 300 Failure area

Claims

1. An apparatus comprising: an exposed portion facing the outside; and a vibration source capable of vibrating the exposed portion; wherein the exposed portion has a maximum displacement portion where the amount of displacement caused by vibration of the vibration source is maximum, and a minimum displacement portion where the amount of displacement caused by the vibration source is minimum; the maximum displacement portion and the minimum displacement portion are located at positions opposite each other with respect to the center of the exposed portion; and the exposed portion has a displacement gradient defined by the following formula (1): (A-B) / L formula (1) [in formula (1), A is the maximum displacement amount (μm) that is the displacement amount of the maximum displacement portion, B is the minimum displacement amount (μm) that is the displacement amount of the minimum displacement portion, and L is the distance (mm) between the maximum displacement portion and the minimum displacement portion]; and the displacement gradient is defined by the following formula (2): C≧2.3935e －０．１７６Ｂ A sensor device defined by equation (2): wherein C is the displacement slope rate, B is the minimum displacement amount, and e is Napier's constant.

2. A device comprising an exposed portion facing the outside and a vibration source capable of vibrating the exposed portion, wherein the exposed portion has a maximum displacement portion where the amount of displacement caused by vibration of the vibration source is maximum, and a minimum displacement portion where the amount of displacement caused by the vibration source is minimum, the maximum displacement portion and the minimum displacement portion are located at positions opposite each other with respect to the center of the exposed portion, the exposed portion has a displacement gradient defined by the following formula (1): (A-B) / L formula (1) [in formula (1), A is the maximum displacement amount (μm) that is the displacement amount of the maximum displacement portion, B is the minimum displacement amount (μm) that is the displacement amount of the minimum displacement portion, and L is the distance (mm) between the maximum displacement portion and the minimum displacement portion], and the displacement gradient rate satisfies the following formula (3): C≧3.6203e －０．１３２Ｂ A sensor device defined by equation (3): wherein C is the displacement gradient rate, B is the minimum displacement amount, and e is Napier's constant.

3. The displacement gradient rate satisfies the following formula (4): C≧3.2337e －０．０９３Ｂ The sensor device of claim 2 , defined by Equation (4): where C is the displacement slope rate, B is the minimum displacement, and e is Napier's constant.

4. The sensor device according to claim 2, wherein the minimum displacement is 15 μm or more and the displacement gradient rate is 1.0 μm / mm or more.

5. A sensor device according to any one of claims 1 to 4, wherein the minimum displacement portion is positioned vertically above the maximum displacement portion.

6. The sensor device according to any one of claims 1 to 5, wherein the exposed portion has an exposed surface that is water-repellent.

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