JP2014211358A - Raindrop detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the device size of a raindrop detector while maintaining the area of a raindrop detection area.SOLUTION: The present raindrop detector is provided with a first reflection unit 40 disposed opposite to a light-receiving unit 30 across a light-emitting unit 20 and causing light radiated opposite to the light-receiving unit 30, among the light radiated from the light-emitting unit 20, to be reflected by a first reflection surface 41 and guided to a transparent plate-like body 70 side. The raindrop detector also has a window part 51 of a bowl shape depressed in a direction parting from the transparent plate-like body 70 in which the light-emitting unit 30 is disposed, and a second reflection surface 52 provided around the window part 51, and is further provided with a second reflection unit 50 for causing light reflected by either the first reflection unit 40 or the transparent plate-like body 70 to be reflected by the second reflection surface 52 and condensed on the light-receiving unit 30. This ensures that not only the light totally reflected by the transparent plate-like body 70, but other diffused light is also guided to the light-receiving unit 30, making it unnecessary to secure the distance between the light-emitting unit 20 and the light-receiving unit 30 in order to have light totally reflected by the transparent plate-like body 70.

Description

  The present invention relates to a raindrop detection device that detects that raindrops are attached to a transparent plate-like body.

  Conventionally, for example, Patent Document 1 proposes a raindrop detection device configured to detect raindrops. Specifically, in Patent Document 1, the light emitted from the light emitting means enters the raindrop detection area of the glass surface at an incident angle of, for example, about 45 °, and the light reflected by the glass surface is detected by the light receiving means. There has been proposed a raindrop detection apparatus configured as described above. According to such a configuration, the transmittance of the glass changes due to raindrops adhering to the glass surface, so that the intensity of light detected by the light receiving means changes. Thereby, raindrops are detected.

JP 2007-33153 A

  However, in the above conventional technique, the raindrop detection device is configured so that the incident angle of light on the glass surface is about 45 °. Therefore, the arrangement of the light emitting means and the light receiving means is determined, so that the raindrop detection device is arranged. The overall size is determined. In other words, the raindrop detection area becomes smaller than the size of the raindrop detection device. For this reason, if the raindrop detection device is made smaller, the raindrop detection area becomes smaller, which makes it difficult to downsize the raindrop detection device.

  In view of the above points, an object of the present invention is to reduce the size of a raindrop detection device while maintaining the area of a raindrop detection area.

  In order to achieve the above object, according to the first aspect of the present invention, the transparent plate-like body (71) is disposed on the inner surface (71) side of the transparent plate-like body (70) having the inner surface (71) and the outer surface (72). 70) and light receiving means (20) for receiving light reflected by the transparent plate (70) and disposed on the inner surface (71) side of the transparent plate (70). 30), and a raindrop detection device that detects that raindrops have adhered to the outer surface (72) of the transparent plate-like body (70) based on the intensity of light received by the light receiving means (30), It is characterized by.

  That is, the light emitted from the light emitting means (20) is disposed on the inner surface (71) side of the transparent plate-like body (70), provided on the opposite side of the light receiving means (30) with respect to the light emitting means (20). Among them, the first reflecting means (40) for reflecting the light irradiated to the side opposite to the light receiving means (30) by the first reflecting surface (41) and guiding it to the transparent plate-like body (70) side is provided.

  Moreover, it is a bowl shape recessed in the direction away from the transparent plate-like body (70), and a window part (51) in which the light receiving means (30) is disposed, and a first part provided around the window part (51). And the light reflected by either the first reflecting means (40) or the transparent plate (70) is reflected by the second reflecting surface (52). A second reflecting means (50) for condensing light on the light receiving means (30) is provided.

  According to this, since light can be reflected by the first reflecting means (40) and the second reflecting means (50), not only the light totally reflected by the transparent plate (70) but also other diffused light is received. The means (30) can be led. That is, the light emitted from the light emitting means (20) is directly applied to the transparent plate (70) at a predetermined angle, and the light reflected by the transparent plate (70) is not directly received by the light receiving means (30). Therefore, it is not necessary to increase the distance between the light emitting means (20) and the light receiving means (30). Therefore, it is possible to reduce the size of the raindrop detection device while maintaining the area of the raindrop detection area (73) set in the transparent plate (70) at a predetermined size.

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

It is sectional drawing of the raindrop detection apparatus in 1st Embodiment of this invention. It is an electrical block diagram of the raindrop detection apparatus shown by FIG. It is a flowchart for demonstrating the action | operation of the raindrop detection apparatus shown by FIG. It is a partial sectional view of the 2nd reflective part concerning a 2nd embodiment. It is a partial sectional view of the 2nd reflective part concerning a 2nd embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. The raindrop detection device shown in the present embodiment is used for detecting raindrops attached to a windshield of a vehicle, for example.

  As shown in FIG. 1, the raindrop detection apparatus 1 includes a case 10, a light emitting unit 20, a light receiving unit 30, a first reflecting unit 40, a second reflecting unit 50, and a circuit board 60.

  The case 10 is a bottomed cylindrical casing for housing the light emitting unit 20, the light receiving unit 30, the first reflecting unit 40, the second reflecting unit 50, and the circuit board 60. The case 10 is formed from a metal material or a resin material. In the present embodiment, the planar shape of the case 10 viewed from the open end 11 side to the bottom surface 12 side is a quadrangular shape.

  Further, the case 10 is fixed to the inner surface 71 side of the transparent plate-like body 70 so as to form a space 13 between the case 10 and the inner surface 71 of the transparent plate-like body 70. Accordingly, the light emitting unit 20, the light receiving unit 30, the first reflecting unit 40, the second reflecting unit 50, and the circuit board 60 are disposed on the inner surface 71 side of the transparent plate 70. The transparent plate-like body 70 is a vehicle windshield.

  The light emitting unit 20 is a light emitting element that emits measurement light for detecting raindrops attached to the outer surface 72 of the transparent plate-like body 70. The light emitting unit 20 is mounted on the circuit board 60. The light emitting unit 20 includes, for example, a light emitting diode (LED) and a drive circuit (not shown) that drives the light emitting diode. The drive circuit performs PWM control of the light emitting diode, for example. That is, the drive circuit blinks the light emitting diode by the pulse signal. Of course, the light emitting diode may be driven with a constant voltage.

  The light emitting unit 20 emits light toward the transparent plate-like body 70 side. That is, the measurement light is emitted from the light emitting unit 20 in all directions on the transparent plate-like body 70 side. Therefore, as shown in FIG. 1, the measurement light is also irradiated on the side opposite to the light receiving unit 30.

  The light receiving unit 30 is a light receiving element that receives light reflected by the transparent plate 70. Specifically, the light receiving unit 30 includes a photodiode (PD) that detects the intensity of the received light, and a processing circuit (not shown) that amplifies a signal of the photodiode.

  The light receiving unit 30 is mounted on the circuit board 60. In the present embodiment, the light receiving unit 30 is arranged together with the light emitting unit 20 in the surface direction of the inner surface 71 of the transparent plate-like body 70. In other words, the light emitting unit 20 and the light receiving unit 30 are arranged in one of the surface directions of the bottom surface 12 of the case 10.

  The first reflecting unit 40 is a reflecting unit that reflects the light irradiated from the light emitting unit 20 to the side opposite to the light receiving unit 30 by the first reflecting surface 41 and guides it to the transparent plate-like body 70 side. is there. For this reason, the 1st reflection part 40 is provided in the wall surface 14 of case 10 on the opposite side to the light-receiving part 30 on the basis of the light emission part 20. FIG. The wall surface 14 is an inner wall surface that is vertically connected to the bottom surface 12.

  In the present embodiment, the first reflecting unit 40 is provided on the wall surface 14 facing the light emitting unit 20 among the four wall surfaces 14 of the case 10. Further, the first reflecting portion 40 is disposed on the transparent plate-like body 70 side with respect to the light emitting surface 21 of the light emitting portion 20. This is because the measurement light is not irradiated to the bottom surface 12 side of the case 10 relative to the light emitting surface 21 of the light emitting unit 20.

  The second reflecting unit 50 is a condensing unit that reflects the light reflected by either the first reflecting unit 40 or the transparent plate-like body 70 by the second reflecting surface 52 and collects the light on the light receiving unit 30. The second reflecting portion 50 is fixed to the circuit board 60 via the pedestal 61. The second reflecting portion 50 has a bowl shape that is recessed in a direction away from the transparent plate 70. Here, the term “cocoon shape” refers to the shape of a part of a spherical shell, the shape of a contact lens, the surface shape of an egg shell, or the like. That is, the second reflecting surface 52 is a concave surface.

  Further, the second reflecting portion 50 includes a window portion 51 and a second reflecting surface 52 provided around the window portion 51. The window portion 51 is a through hole that penetrates the second reflecting portion 50. The light receiving unit 30 is disposed in the window 51. The pedestal 61 is also provided with the light receiving portion 30 and a window portion 62 that communicates with the window portion 51 of the second reflecting portion 50.

  In the present embodiment, the second reflecting surface 52 is configured by a curved surface. In the present embodiment, the portion of the second reflecting portion 50 that faces the first reflecting portion 40 extends to the opening end 11 side of the case 10. On the other hand, the light emitting unit 20 side of the second reflecting unit 50 is formed to have a lower height from the bottom surface 12 of the case 10 than the wall surface 14 side of the case 10.

  The first reflection surface 41 of the first reflection unit 40 and the second reflection surface 52 of the second reflection unit 50 are made of a reflection material that reflects light more than light is absorbed or transmitted. For example, metallic materials such as Al, Ag, Au, Cu, white paint, enamel, paint such as enamel, resin, paper such as blotter paper, Kent, bird cub, stone materials such as white tile Can be adopted.

  The material reflectivity of the metal material is about 50% to 90% depending on the metal. The material reflectivity of the paint is approximately 70% to 85%. The material reflectance of the stone is about 70% to 80% in the case of a white tile.

  As described above, the light reflectance varies depending on the reflective material, but the light reflectance of each of the first reflective surface 41 and the second reflective surface 52 is 50% or more. In addition, not only each reflective surface 41 and 52 but the whole 1st reflection part 40 and the whole 2nd reflection part 50 may be comprised with said metal material, resin material, etc. FIG.

  For example, in the present embodiment, the first reflecting surface 41 is formed by depositing a metal material such as Al on the base of the first reflecting portion 40. The base body of the first reflecting portion 40 may be a separate part from the case 10 or may be a portion formed on the wall surface 14 when the case 10 is formed. In addition, the second reflecting surface 52 is formed by depositing a metal material such as Al on the base material to be the second reflecting portion 50. Thus, uniform reflective surfaces 41 and 52 can be formed by vapor-depositing a metal material as a reflective material on the bases of the reflective portions 40 and 50, respectively.

  The circuit board 60 includes a circuit (not shown) for driving the light emitting unit 20, the light receiving unit 30, the second reflecting unit 50, the light emitting unit 20, and the light receiving unit 30. The circuit board 60 is disposed on the bottom surface 12 of the case 10.

  According to the configuration of the raindrop detection apparatus 1 described above, as shown in FIG. 1, the measurement light emitted from the light emitting unit 20 is reflected by the first reflecting unit 40 and the transparent plate 70, and further the second reflecting unit. The light is reflected by 50 and received by the light receiving unit 30.

  Specifically, of the measurement light emitted from the light emitting unit 20, the measurement light emitted to the side opposite to the light receiving unit 30 side is reflected by the first reflecting surface 41 of the first reflecting unit 40. For example, light incident on the first reflection unit 40 at 70 ° is incident and reflected on the outer surface 72 of the transparent plate-like body 70 at an angle of 20 °, and the light receiving unit among the second reflection surfaces 52 of the second reflection unit 50. The light is reflected by the second reflecting surface 52 closer to the wall surface 14 of the case 10 than 30 and received by the light receiving unit 30.

  Further, the light incident on the first reflecting surface 41 of the first reflecting portion 40 at 45 ° is incident on the outer surface 72 of the transparent plate-like body 70 at an angle of 45 °, so that it is totally reflected in the total reflection region of the transparent plate-like body 70. Further, the light is reflected by the second reflecting surface 52 of the second reflecting portion 52 of the second reflecting portion 50 on the wall surface 14 side of the case 10 from the light receiving portion 30 and is received by the light receiving portion 30. Furthermore, the light incident on the first reflecting portion 40 at 10 ° is incident on and reflected by the outer surface 72 of the transparent plate-like body 70 at an angle of 80 °, and further, the light receiving portion of the second reflecting surface 52 of the second reflecting portion 50. The light is reflected by the second reflecting surface 52 closer to the light emitting unit 20 than 30 and received by the light receiving unit 30.

  On the other hand, of the measurement light emitted from the light emitting unit 20, the measurement light emitted to the light receiving unit 30 side is reflected by the outer surface 72 of the transparent plate 70 and further reflected by the second reflecting surface 52 of the second reflecting unit 50. The light receiving unit 30 receives the light. Alternatively, the measurement light is multiple-reflected by the outer surface 72 of the transparent plate-like body 70 and the second reflection surface 52 of the second reflection unit 50 and received by the light receiving unit 30.

  In this way, light incident on and reflected from the transparent plate 70 at an angle other than a certain angle can be guided to the light receiving unit 30. That is, the range from the first reflecting surface 41 of the first reflecting unit 40 to the second reflecting surface 52 of the second reflecting unit 50 on the outer surface 72 of the transparent plate-like body 70 is the raindrop detection area 73.

  Of course, these measurement light paths are merely examples. As described above, since the measurement light is emitted from the light emitting unit 20 in all directions on the transparent plate-like body 70 side, the first reflecting surface 41 of the first reflecting portion 40 and the transparent plate-like body 70 are routed according to each direction. And reflected by the second reflecting surface 52 of the second reflecting unit 50 and received by the light receiving unit 30.

  As shown in FIG. 2, the light emitting unit 20 and the light receiving unit 30 constitute a raindrop detection apparatus 1 together with the CPU 62. The CPU 62 has a function of irradiating measurement light from the light emitting unit 20, a function of detecting that raindrops have adhered to the outer surface 72 of the transparent plate 70 based on the intensity of light received by the light receiving unit 30, and raindrop detection results Is a control means having a function of outputting to the outside.

  The raindrop detection device 1 is electrically connected to an ECU 80 for operating a wiper of the vehicle. The ECU 80 controls the operation of the wiper for wiping off the raindrops on the windshield based on the raindrop detection result of the raindrop detection device 1.

  Next, the operation of the raindrop detection apparatus 1 will be described with reference to the flowchart of FIG. It is assumed that the space 13 of the case 10, particularly the inner surface 71 of the transparent plate 70 and the lens of the light receiving unit 30 are not fogged and are not affected by sunlight.

  The flowchart shown in FIG. 3 starts when, for example, the vehicle is turned on or the user operates a predetermined switch. First, in step 100, measurement light irradiation and measurement light detection are performed. That is, the measurement light irradiated from the light emitting unit 20 and reflected by the first reflection unit 40, the transparent plate 70, and the second reflection unit 50 is received by the light receiving unit 30.

  In the light receiving unit 30, the intensity of the measurement light is detected as a voltage value, for example. When raindrops are not attached to the outer surface 72 of the transparent plate-like body 70, the intensity of the measurement light detected by the light receiving unit 30 is A, for example. On the other hand, when raindrops adhere to the raindrop detection area 73 in the outer surface 72 of the transparent plate-like body 70, the amount of measurement light reflected by the transparent plate-like body 70 decreases, so that the measurement light detected by the light receiving unit 30 is reduced. The strength is, for example, A-α.

  The intensity of the measurement light measured by the light receiving unit 30 is, in other words, the amount of measurement light. In other words, the amount of light received by the light receiving unit 30 is “A” in a normal time when no raindrops are attached to the outer surface 72 of the transparent plate-like body 70. On the other hand, the amount of light received by the light receiving unit 30 when raindrops are attached is A-α, and the amount of light decreases by α. That is, α is a threshold value for raindrop detection.

  Subsequently, in step 110, raindrop detection determination is performed. Specifically, when the intensity of the measurement light detected in step 100 is A, the process proceeds to step 120, and when the intensity of the measurement light is A−α, the process proceeds to step 130.

  In step 120, it is determined that it is not raining. Then, returning to step 100, the measurement light is irradiated again and the measurement light is detected again. On the other hand, in step 130, it is determined that it is raining. That is, the raindrop is detected from the attenuation amount α of the intensity (light quantity) of the measurement light received by the light receiving unit 30. Then, the process proceeds to Step 140.

  In step 140, wiper control is performed. The wiper control in this step is, for example, control for operating the wiper once. That is, the wiper is reciprocated once. Specifically, a wiper control signal is output from the CPU 62 of the raindrop detection apparatus 1 to the ECU 80. The ECU 80 having input the wiper control signal operates the wiper once. Thereafter, the process returns to step 100 again, and measurement light irradiation and measurement light detection are performed again.

  When rain continues and raindrops continue to adhere to the outer surface 72 of the transparent plate-like body 70, Step 100, Step 110, Step 130, and Step 140 are repeated.

  As described above, in the present embodiment, the first reflection unit 40 that guides the measurement light emitted in the direction away from the light receiving unit 30 out of the measurement light emitted from the light emitting unit 20 to the light receiving unit 30 side is provided. It is a feature. Further, the second reflection unit 50 is characterized in that the measurement light reflected by the first reflection unit 40 and the transparent plate-like body 70 is collected on the light receiving unit 30.

  Thereby, the light can be reflected by the first reflecting unit 40 and the second reflecting unit 50 and further condensed on the light receiving unit 30. For this reason, the light irradiated from the light emitting unit 20 may be directly applied to the transparent plate-like body 70 at an angle to totally reflect, and the light reflected by the transparent plate-like body 70 may not be directly received by the light receiving unit 30. That is, not only the light totally reflected by the transparent plate-like body 70 but also other diffused light can be condensed on the light receiving unit 30. As described above, since the diffused light in the space 13 of the case 10 is condensed on the light receiving unit 30 by the second reflecting unit 50, it is not necessary to secure a distance between the light emitting unit 20 and the light receiving unit 30. Therefore, the raindrop detection apparatus 1 can be reduced in size while maintaining the area of the raindrop detection area 73 set in the transparent plate-like body 70 at a predetermined size.

  In the present embodiment, the second reflecting surface 52 of the second reflecting unit 50 is configured by a smooth curved surface. Therefore, the light reflected by the second reflecting surface 52 can be easily collected on the light receiving unit 30.

  As for the correspondence between the description of the present embodiment and the description of the claims, the light emitting unit 20 corresponds to the “light emitting means” in the claims, and the light receiving unit 30 corresponds to the “light receiving means” in the claims. ". The first reflecting portion 40 corresponds to “first reflecting means” in the claims, and the second reflecting portion 50 corresponds to “second reflecting means” in the claims.

(Second Embodiment)
In the present embodiment, parts different from the first embodiment will be described. In this embodiment, as FIG.4 and FIG.5 shows, the 2nd reflective surface 52 of the 2nd reflective part 50 is not a curved surface, but is comprised from the several plane part 53. As shown in FIG. Although the curved second reflecting surface 52 is fine, it can be said that this surface is rough in this embodiment.

  As shown in FIG. 4, for example, the angle z <b> 1 of the flat surface portion 54 on the opening end 11 side of the case 10 in the portion of the second reflecting portion 50 located on the side opposite to the light emitting portion 20 in the light receiving portion 30 is designed. In this case, z1 can be derived from z1 = (180−x1−y1) / 2. For example, assuming that x1 = 60 ° and y1 = 20 °, z1 becomes z1 = 50 ° from the above formula.

  Further, as shown in FIG. 5, when designing the angle z <b> 2 of the flat portion 55 of the portion of the second reflecting portion 50 that is located closer to the light emitting portion 20 than the light receiving portion 30, z2 is z2 = (y2−x2). ) / 2. For example, if x2 = 20 ° and y2 = 80 °, z2 is z2 = 30 ° from the above equation. In addition, the light emission part 20 is abbreviate | omitted in FIG.

  As described above, the plane portions 53 to 55 are formed by designing the dimensions of the second reflecting surface 52 of the second reflecting portion 50 to reflect the measurement light at each position of the second reflecting surface 52. It becomes. Thus, the design of the second reflecting surface 52 of the second reflecting portion 50 can be facilitated by configuring the second reflecting surface 52 with the plurality of flat surface portions 53 to 55. Moreover, since the 2nd reflective surface 52 is not a curved surface, manufacture of the 2nd reflective part 50 can be made easy.

(Other embodiments)
The configuration of the raindrop detection device 1 shown in each of the above embodiments is an example, and is not limited to the configuration shown above, and may be another configuration that can realize the present invention. For example, the second reflecting unit 50 may be directly fixed to the circuit board 60 or the bottom surface 12 of the case 10 without using the pedestal 61. The first reflecting portion 40 is positioned not only on one wall surface 14 of the case 10 but also in a direction perpendicular to the direction in which the light emitting portion 20 and the light receiving portion 30 are arranged in the surface direction of the bottom surface 12 of the case 10. It may be provided in a part of two wall surfaces 14 to be.

  In each of the above embodiments, the case 10 and the reflecting portions 40 and 50 are separate components, but the wall surface 14 of the case 10 may be formed as the first reflecting portion 40 and the second reflecting portion 50. Moreover, the 1st reflective surface 41 may be formed by the 1st reflection part 40 being shape | molded by the resin material. Similarly, the 2nd reflective surface 52 may be formed by shape | molding the 2nd reflective part 50 with the resin material. On the other hand, although each reflective part 40 and 50 is shape | molded with the resin material with the case 10, each reflective surface 41 and 52 may be formed with another reflective material. For example, as described above, a reflective material may be deposited.

  As described above, in the case where the base material of each of the reflecting portions 40 and 50 and the reflecting material having the reflecting surfaces 41 and 52 are separate bodies, the first reflecting portion 40 has the reflecting material having the first reflecting surface 41 as the first reflecting portion 40. It may be formed by being bonded to the mother body. Similarly, the second reflection unit 50 may be formed by bonding a reflective material having the second reflection surface 52 to the base of the second reflection unit 50. According to this, since the base material of each reflection part 40 and 50 and the reflective material which has the reflective surfaces 41 and 52 can be prepared separately, the freedom degree of design can be improved.

  Further, in each of the above embodiments, the case 10 has a bottomed cylindrical shape with the bottom surface 12 having a quadrangular shape, but this is an example of the shape of the case 10. Therefore, for example, the bottom surface 12 of the case 10 is circular or elliptical, and the first reflecting portion 40 is disposed in one half region of the circle or ellipse, and the second reflecting portion 50 is disposed in the other half region. May be.

  The raindrop detection device 1 is not limited to being mounted on a vehicle. Therefore, it can be applied to a window glass of a building or the like. In this case, the raindrop detection result of the raindrop detection apparatus 1 may be output not to the ECU 80 but to a device that performs an operation according to the raindrop detection result.

20 Light emitting part (light emitting means)
30 Light receiving part (light receiving means)
40 1st reflection part (1st reflection means)
41 1st reflection surface 50 2nd reflection part (2nd reflection means)
51 Window 52 Second Reflecting Surface 70 Transparent Plate 71 Inner Surface 72 Outer Surface

Claims (8)

A light emitting means (20) disposed on the inner surface (71) side of the transparent plate (70) having an inner surface (71) and an outer surface (72), and emitting light toward the transparent plate (70); ,
A light receiving means (30) disposed on the inner surface (71) side of the transparent plate (70) and receiving light reflected by the transparent plate (70);
A raindrop detection device that detects that raindrops have adhered to the outer surface (72) of the transparent plate-like body (70) based on the intensity of light received by the light receiving means (30),
Arranged on the inner surface (71) side of the transparent plate-like body (70), provided on the opposite side of the light receiving means (30) with respect to the light emitting means (20), and irradiated from the light emitting means (20). First reflecting means (40) for reflecting the light irradiated on the opposite side of the light receiving means (30) from the first reflecting surface (41) to the transparent plate-like body (70) side. ,
It has a bowl shape recessed in a direction away from the transparent plate-like body (70), and a window portion (51) in which the light receiving means (30) is disposed, and a first portion provided around the window portion (51). And the light reflected by either the first reflecting means (40) or the transparent plate (70) is reflected by the second reflecting surface (52). Second reflecting means (50) for reflecting and condensing on the light receiving means (30);
A raindrop detection apparatus comprising:   The raindrop detection device according to claim 1, wherein the second reflecting surface (52) is formed of a curved surface.   The raindrop detection device according to claim 1, wherein the second reflection surface (52) includes a plurality of flat portions (53 to 55).   The first reflection surface (41) and the second reflection surface (52) are any of a metal material, a resin material, paper, and a stone material as a reflection material that reflects light more than light is absorbed or transmitted. The raindrop detection device according to claim 1, wherein the raindrop detection device is formed by:   The raindrop detection according to any one of claims 1 to 4, wherein the first reflective surface (41) and the second reflective surface (52) each have a light reflectance of 50% or more. apparatus. The first reflecting surface (41) is formed by depositing a metal material on the base of the first reflecting means (40),
The said 2nd reflective surface (52) is formed by vapor-depositing a metal material on the base | substrate of the said 2nd reflection means (50), The one of Claim 1 thru | or 5 characterized by the above-mentioned. Raindrop detector. The first reflecting means (40) is formed by adhering a reflective material having the first reflecting surface (41) to a base body of the first reflecting means (40),
The second reflecting means (50) is formed by adhering a reflecting material having the second reflecting surface (52) to a base body of the second reflecting means (50). The raindrop detection apparatus according to any one of 1 to 5. The first reflecting surface (41) is formed by molding the first reflecting means (40) with a resin material,
6. The raindrop according to claim 1, wherein the second reflecting surface (52) is formed by molding the second reflecting means (50) with a resin material. Detection device.

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