Rain detector

Abstract

To provide a rain detector which can suppress increase of size of a device in a case where the range of detecting rain is enlarged.SOLUTION: A rain detector 50 includes: a light-emitting element 1 for emitting light from a light-emitting unit 12; a light-receiving element 2 for receiving reflection light which returned to the light-emitting element 1 side by a light-receiving unit 22 of light emitted from the light-emitting unit 12 of the light-emitting element 1; and a detector 7 for detecting rain according to light received by the light-receiving element 2. The light-emitting unit 12 of the light-emitting element 1 and the light-receiving unit 22 of the light-receiving element 2 face the same direction.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a rain detection device. [Background technology]

[0002] Patent Document 1 discloses a raindrop detection device in which a raindrop sensor unit consisting of a light-emitting element and a light-receiving element is integrated and disposed inside the windshield of a vehicle. In the raindrop detection device of Patent Document 1, the light-emitting element and the light-receiving element are provided separately so that the light emitted from the light-emitting element is totally reflected at least once by the windshield and then received by the light-receiving element.

[0003] Patent Document 2 discloses a raindrop detection device that includes a first reflecting surface provided on the opposite side of the light-emitting element from the light-receiving element, and a recessed second reflecting surface provided around the light-receiving element. In the raindrop detection device of Patent Document 2, light emitted from the light-emitting element is reflected by the first reflecting surface and directed toward a transparent plate-like body. The light reflected by the transparent plate-like body is directed toward the second reflecting surface, reflected by the second reflecting surface, and then received by the light-receiving element. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 57-88346 [Patent Document 2] JP 2014-211358 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the conventional techniques such as those disclosed in Patent Documents 1 and 2, in order to expand the rain detection range, it was necessary to basically expand the distance between the light-emitting element and the light-receiving element. Increasing the distance between the light-emitting element and the light-receiving element in this way poses the problem that the device equipped with the light-emitting element and the light-receiving element becomes larger.

[0006] The present disclosure has been made to solve the above-mentioned problems, and its purpose is to provide a rain detection device that can prevent the device from becoming larger when the rain detection range is expanded. [Means for solving the problem]

[0007] A rain detection device according to one aspect of the present disclosure includes a light-emitting element that emits light from a light-emitting unit, a light-receiving element that is capable of receiving reflected light that returns to the light-emitting element from the light-emitting unit of the light-emitting element in a light-receiving unit, and a detection unit that detects rain in response to the light received by the light-receiving element, and is arranged so that the light-emitting unit of the light-emitting element and the light-receiving unit of the light-receiving element face the same side. Effect of the Invention

[0008] According to the present disclosure, when the rain detection range is expanded, the size of the device can be suppressed. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing an example of installation of a rain detection device according to a first embodiment. [Diagram 2] FIG. 2 is a diagram showing a configuration of the rain detection device according to the first embodiment. [Diagram 3] FIG. 3 is a diagram showing an example of how infrared light travels inside the front windshield of the rain detection device according to the first embodiment. [Figure 4] FIG. 4 is a cross-sectional view showing a configuration example of a signal processing circuit in the rain detection device according to the first embodiment. [Diagram 5] FIG. 5 is a diagram showing a configuration of a photodetector according to the second embodiment. [Figure 6] FIG. 6 is a diagram showing a configuration of a rain detection device according to the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the drawings. In the following, the same or corresponding parts in the drawings will be denoted by the same reference numerals, and the description thereof will not be repeated in principle. Although several embodiments will be described below, it is planned from the beginning of the application that the configurations described in each embodiment will be appropriately combined.

[0011] <Embodiment 1> In the first embodiment, a configuration of a rain detection device 50 in which a light emitting element 1 and a light receiving element 2 are arranged side by side in a direction intersecting the optical axis of light emitted by the light emitting element 1 will be described.

[0012] [Installation example of rain detection device 50] Fig. 1 is a diagram showing an example of installation of a rain detection device 50 according to the first embodiment. In the example of Fig. 1, a side view of a vehicle 100 is shown. Fig. 1 shows a configuration in which the rain detection device 50 is installed on the inside of a glass windshield 60 of the vehicle 100, such as an automobile. The windshield 60 is a translucent plate-like body.

[0013] The rain detection device 50 is a rain sensor that detects rain including raindrops in the vehicle 100. The rain detection device 50 includes a sensor body 10 in which a light emitting element 1 and a light receiving element 2 are provided on a semiconductor substrate 11 as shown in FIG.

[0014] [Example of configuration of rain detection device 50] Fig. 2 is a diagram showing the configuration of the rain detection device 50 according to the embodiment 1. Fig. 2 shows an enlarged view of the internal configuration of the rain detection device 50 and the surrounding area of ​​the windshield 60 where the rain detection device 50 is provided.

[0015] 2 shows the rain detection device 50 and the windshield 60 as viewed from the inside of the windshield 60 of the vehicle 100. In order to clearly show the configurations of the light-emitting element 1 and the light-receiving element 2, the configuration of the rain detection device 50 other than the light-emitting element 1 and the light-receiving element 2 is shown by a simple frame line in FIG.

[0016] The rain detection device 50 includes a housing 51 and a sensor body 10. The rain detection device 50 further includes a first light guide 41 and a first adhesive 31, and a second light guide 42 and a second adhesive 32, as described later with reference to FIG. 3, but these are omitted in FIG. 2. The housing 51 has a rectangular box shape (see FIG. 1) and is open on the side facing the bottom. The sensor body 10 is provided inside the housing 51. The sensor body 10 includes a light emitting element 1 and a light receiving element 2 provided on a semiconductor substrate 11.

[0017] The sensor body 10 further includes a detection unit 7 provided on the semiconductor substrate 11, as will be described later with reference to Fig. 4. The detection unit 7 is omitted in Fig. 2.

[0018] 1, the windshield 60 is inclined at a predetermined angle with respect to the horizontal direction of the vehicle 100. The rain detection device 50 is attached to the inside of the windshield 60 so that the bottom surface inside the housing 51 faces the windshield 60 through the opening of the housing 51. In this way, the rain detection device 50 is attached to the inside of the windshield 60 in a state inclined with respect to the horizontal direction at the same angle as the windshield 60.

[0019] The sensor body 10 is attached to the bottom surface inside the housing 51 so that the surface faces the front window 60. As a result, inside the housing 51, the light-emitting portion 12 of the light-emitting element 1 and the light-receiving portion 22 of the light-receiving element 2 face the front window 60.

[0020] The light-emitting element 1 is an element provided for emitting infrared light used for detecting rain. The light-receiving element 2 is an element provided for receiving infrared light used for detecting rain. The light-emitting element 1 of the first embodiment has a light-emitting unit 12, and emits infrared light L from the light-emitting unit 12. The infrared light L is light that spreads around an optical axis L0 with a certain width. The infrared light L emitted from the light-emitting unit 12 of the light-emitting element 1 enters the inside of the front window 60 from a first surface of the front window 60.

[0021] The infrared light L that enters the inside of the front window 60 is repeatedly reflected between the second surface and the first surface, and travels inside the front window 60 to an end surface 63 at the upper edge of the front window 60, as shown by the dashed arrow in Fig. 2. The infrared light L having, for example, a light width LW shown in Fig. 2 is incident on the end surface 63. Inside the front window 60, the infrared light L that travels in this manner and is incident on the end surface 63 is reflected by the end surface 63.

[0022] In FIG. 2, light L2 is shown as a representative example of the light after the infrared light L is reflected by the end surface 63. Specifically, the light L2 is the light after the light L1 included in the infrared light L incident on the end surface 63 is reflected by the end surface 63. The light L2, which is the light after the light L1 is reflected by the end surface 63, returns to the vicinity of the light emitting element 1 of the front window 60 inside the front window 60 while repeatedly reflecting between the second surface and the first surface, as shown by the dashed arrow in FIG. 2, and is emitted from inside the front window 60 to the outside through the first surface. The light L2 emitted to the outside of the front window 60 is received by the light receiving element 2. The light receiving element 2 has a light receiving unit 22, and the light receiving unit 22 receives the light L2.

[0023] The principle by which the rain detection device 50 detects rain containing raindrops is, for example, as follows. When rain containing raindrops is attached to the windshield 60, the amount of infrared light received by the light receiving section 22 of the light receiving element 2 is reduced in response to a decrease in the amount of infrared light reflected by the windshield 60 compared to when rain containing raindrops is not attached to the windshield 60. This is because, when rain containing raindrops is attached to the windshield 60, the amount of infrared light going out from the windshield 60 to the outside is greater than when rain containing raindrops is not attached to the windshield 60. Therefore, the rain detection device 50 can detect the rainfall state in response to detecting the amount of infrared light received by the light receiving section 22 of the light receiving element 2.

[0024] In the rain detection device 50, the light emitting section 12 of the light emitting element 1 and the light receiving section 22 of the light receiving element 2 are arranged to face the same side. In the example of Fig. 2, both the light emitting section 12 of the light emitting element 1 and the light receiving section 22 of the light receiving element 2 are arranged to face the same side, that is, the side of the object of rain detection. The side of the object of rain detection is the side of the rain detection area on the windshield 60.

[0025] More specifically, in the rain detection device 50, the light-emitting element 1 and the light-receiving element 2 are arranged so that the direction in which the light-emitting unit 12 of the light-emitting element 1 emits light is the same as the direction in which the light-receiving unit 22 of the light-receiving element 2 receives light. In the rain detection device 50, the light-emitting element 1 and the light-receiving element 2 are arranged side by side in a direction intersecting the direction of the optical axis L0 of the infrared light L emitted by the light-emitting unit 12 of the light-emitting element 1.

[0026] The fact that the direction in which the light-emitting section 12 of the light-emitting element 1 emits light and the direction in which the light-receiving section 22 of the light-receiving element 2 receives light are the same means that, with respect to the same reflective object such as the edge surface 63 of the front window 60, the direction in which the light-emitting section 12 of the light-emitting element 1 faces to emit light and the direction in which the light-receiving section 22 of the light-receiving element 2 faces to receive light are the same.

[0027] In the rain detection device 50, when the direction in which the light-emitting unit 12 of the light-emitting element 1 emits light and the direction in which the light-receiving unit 22 of the light-receiving element 2 receives light are the same, this includes a case in which the direction in which the light-emitting unit 12 of the light-emitting element 1 emits light and the direction in which the light-receiving unit 22 of the light-receiving element 2 receives light are completely the same direction, and a case in which the direction in which the light-emitting unit 12 of the light-emitting element 1 emits light and the direction in which the light-receiving unit 22 of the light-receiving element 2 receives light are approximately the same direction. The case in which the direction in which the light-emitting element 1 emits light and the direction in which the light-receiving unit 22 of the light-receiving element 2 receives light are approximately the same direction may include, as a minimum condition, a case in which the light-emitting direction of the light-emitting unit 12 of the light-emitting element 1 and the light-receiving direction of the light-receiving unit 22 of the light-receiving element 2 are set to a direction in which the light L1 emitted by the light-emitting unit 12 of the light-emitting element 1 and the light-receiving direction of the light-receiving unit 22 of the light-receiving element 2 can receive the light L2 reflected by the end surface 63.

[0028] In the rain detection device 50, the light-emitting element 1 and the light-receiving element 2 are arranged side by side in a direction intersecting the direction of the optical axis L0 of the light L1 emitted by the light-emitting portion 12 of the light-emitting element 1. Specifically, FIG. 2 shows, as an example, a configuration in which the light-emitting element 1 and the light-receiving element 2 are arranged side by side in a direction perpendicular to the optical axis L0. The light-emitting element 1 and the light-receiving element 2 may be arranged side by side in any direction, not limited to the direction perpendicular to the optical axis L0, as long as it intersects with the optical axis L0. However, the light-emitting element 1 and the light-receiving element 2 need to be arranged in a positional relationship such that the light L1 emitted by the light-emitting element 1 is incident on the end surface 63 and reflected, and the light-receiving element 2 can receive the light L2 after being reflected in this way.

[0029] [Example of infrared light progression inside the front windshield 60] Fig. 3 is a diagram showing an example of the progression of infrared light L inside the front window 60 of the rain detection device 50 according to the first embodiment. Fig. 3(A) shows an example in which light L1 as infrared light progresses between the light-emitting portion 12 of the light-emitting element 1 and the end face 63 at the upper edge of the front window 60. Fig. 3(B) shows an example in which light L2 as infrared light progresses between the end face 63 at the upper edge of the front window 60 and the light-receiving portion 22 of the light-receiving element 2.

[0030] 3(A), the light-emitting element 1 is provided at an angle set with respect to the windshield 60 so that the light L1 emitted from the light-emitting unit 12 travels toward an end surface 63 of the windshield 60. The light-emitting element 1 is provided at an angle set with respect to the windshield 60 so that the light L1 emitted from the light-emitting unit 12 is incident on a first surface 61, which is the inner surface in the thickness direction of the windshield 60 (the inner surface of the vehicle 100), at an angle of, for example, 45 degrees.

[0031] The rain detection device 50 includes a first light guide 41 for guiding the light L1 emitted by the light emitting section 12 of the light emitting element 1 to the inside of the front windshield 60. The first light guide 41 is a translucent optical element. The first light guide 41 guides the light L1 emitted from the light emitting section 12 of the light emitting element 1 so that the light L1 is incident on the inside of the front windshield 60 at a predetermined angle (e.g., 45 degrees). The first light guide 41 is adhered to a first surface 61 of the front windshield 60 by a first adhesive material 31. The first adhesive material 31 is translucent.

[0032] The light L1 emitted from the light-emitting section 12 of the light-emitting element 1 enters the first light guide 41 and is guided by the first light guide 41. The light L1 guided by the first light guide 41 passes through the first adhesive material 31 and enters the front window 60 from the first surface 61.

[0033] Inside the windshield 60, light L1 incident from a first surface 61 travels in the direction of a second surface 62 opposing the first surface 61, and is incident on the second surface 62. The light L1 is incident on the second surface 62 at an angle of, for example, 45 degrees. The second surface 62 is the outer surface of the windshield 60 in the thickness direction (the outer surface of the vehicle 100).

[0034] Light L1 incident on the second surface 62 at an angle of 45 degrees is reflected by the second surface 62. At the second surface 62, the light L1 is reflected at an angle of, for example, 45 degrees with respect to the second surface 62. The light L1 incident on the second surface 62 is totally reflected by the second surface 62, for example, when there is no rain, including raindrops, on the outside of the front window 60.

[0035] The light L1 reflected by the second surface 62 travels inside the front window 60 in the direction of the first surface 61 and is incident on the first surface 61. The light L1 is incident on the first surface 61 at an angle of, for example, 45 degrees. The light L1 incident on the first surface 61 at an angle of 45 degrees is reflected on the first surface 61. On the first surface 61, the light L1 is totally reflected at an angle of, for example, 45 degrees with respect to the first surface 61. The light L1 reflected on the first surface 61 is further incident on the second surface 62 at an angle of 45 degrees. Inside the front window 60, the light L1 is repeatedly reflected between the first surface 61 and the second surface 62 in this manner.

[0036] As shown in Figure 3(A), inside the front window 60, light L1 is repeatedly reflected between the first surface 61 and the second surface 62, causing the light L1 to travel toward the end surface 63 at the upper edge of the front window 60, as indicated by the dashed arrow in Figure 3(A).

[0037] As shown in Fig. 3(A), inside the front window 60, light L1 that reaches the edge surface 63 of the front window 60 is incident on the edge surface 63 of the front window 60 at an angle of, for example, 45 degrees. As shown in Fig. 3(B), the light L1 that is incident on the edge surface 63 is reflected by the edge surface 63. At the edge surface 63, the light L1 is totally reflected at an angle of, for example, 45 degrees with respect to the edge surface 63. In this way, the light L1 that is incident inside the front window 60 travels to the edge surface 63 and is reflected at the edge surface 63.

[0038] 3(B), inside the front window 60, after the light L1 is reflected by the end face 63, the light L2 returns in the direction of the light-emitting element 1 and the light-receiving element 2. As shown by the dashed arrow in FIG. 3(B), the light L2 that is the light reflected by the end face 63 returns in the direction of the light-emitting element 1 and the light-receiving element 2 while repeatedly being reflected between the first surface 61 and the second surface 62 inside the front window 60, in the same way as when the incident light L1 travels to the end face 63.

[0039] Referring to Figure 3 (B), the light receiving element 2 is disposed at an angle set so that the light receiving unit 22 can receive light L2 that is reflected by the end surface 63 of the front window 60, returns to the side of the light emitting element 1 and the light receiving element 2, and is emitted from the first surface 61 of the front window 60 at an angle of, for example, 45 degrees.

[0040] The rain detection device 50 includes a second light guide 42 for guiding the light L2 emitted from the first surface 61 of the front windshield 60 to the light receiving portion 22 of the light receiving element 2. The second light guide 42 is a light-transmitting optical element. The second light guide 42 is adhered to the first surface 61 of the front windshield 60 by a second adhesive material 32. The second adhesive material 32 is light-transmitting. The second light guide 42 guides the light L2, which is light reflected by an end surface 63 of the front windshield 60, so that it is emitted from the inside of the front windshield 60 at a predetermined angle (for example, 45 degrees).

[0041] 3(B), inside the front window 60, the light L2 reflected by the end face 63 returns to the position of the sensor body 10 where the light emitting element 1 and the light receiving element 2 are provided, and then exits from the first surface 61 of the front window 60. The light L2 exiting from the first surface 61 passes through the second adhesive material 32 and is guided by the second light guide 42. The light L2 guided by the second light guide 42 exits from the second light guide 42 toward the light receiving section 22 of the light receiving element 2. As a result, the light receiving element 2 receives the light L2 reflected by the end face 63 and returning, at the light receiving section 22.

[0042] In the rain detection device 50, in the region of the front windshield 60 between the positions where the light-emitting element 1 and the light-receiving element 2 are provided and the position of the edge surface 63 of the front windshield 60, the infrared light L is reflected back and forth between the first surface 61 and the second surface 62. Therefore, the detection region in which the rain detection device 50 can detect rain including raindrops on the front windshield 60 is the region between the positions where the light-emitting element 1 and the light-receiving element 2 are provided and the position of the edge surface 63.

[0043] [Example of the configuration of the signal processing circuit of the rain detection device 50] Fig. 4 is a diagram showing an example of the configuration of a signal processing circuit related to the rain detection device 50 according to the embodiment 1. In Fig. 4, the rain detection device 50 and a control device 8 are shown.

[0044] A detection unit 7 is further provided on the semiconductor substrate 11. The detection unit 7 may be provided on a semiconductor substrate other than the one on which the light emitting element 1 and the light receiving element 2 are provided.

[0045] The detection unit 7 is composed of a computer including a CPU (Central Processing Unit) 71, memory 72 (various storage devices including ROM (Read Only Memory), RAM (Random Access Memory), and non-volatile memory such as flash memory), and an input / output buffer (not shown) for inputting and outputting various signals. The detection unit 7 is composed of an IC chip such as an ASIC (Application Specific Integrated Circuit). Note that the detection unit 7 may be composed of a processing circuit such as a processor other than an ASIC.

[0046] The detection unit 7 is connected to the light-emitting element 1 and the light-receiving element 2. The detection unit 7 transmits a control signal to the light-emitting element 1. The detection unit 7 receives a detection signal input from the light-receiving element 2. The detection unit 7 executes light emission control of the light-emitting element 1 by transmitting a control signal to the light-emitting element 1. The detection unit 7 executes a rain detection process that detects rain based on the detection signal input from the light-receiving element 2 in response to the infrared light received by the light-receiving unit 22 by the light-receiving element 2.

[0047] The ratio of the infrared light emitted from the light-emitting unit 12 of the light-emitting element 1 reflected by the front windshield 60 differs between when there is rain including raindrops on the outside of the front windshield 60 and when there is no rain including raindrops on the outside of the front windshield 60. Therefore, when the same amount of infrared light L is emitted from the light-emitting unit 12 of the light-emitting element 1, the amount of infrared light L received by the light-receiving unit 22 of the light-receiving element 2 differs between when it is raining and when it is not raining. The detection unit 7 executes a rain detection process for detecting rain, which determines that rain has been detected when it is determined, for example, that the amount of infrared light L received by the light-receiving unit 22 of the light-receiving element 2 is equal to or greater than a threshold based on the detection signal input from the light-receiving element 2.

[0048] The ROM stores various software programs that indicate the processing procedures related to the rain detection control executed by the detection unit 7. The CPU 71 loads the software programs stored in the ROM into the RAM or the like and executes them. The CPU 71 executes the software programs stored in the ROM to execute the light emission control and the rain detection process as described above.

[0049] The detection unit 7 is connected to the control device 8. The control device 8 is provided separately from the rain detection device 50 in the vehicle 100 shown in FIG. 1, and executes various controls. The detection unit 7 transmits rain detection information to the control device 8 based on the rain determination result by the rain detection process described above. For example, in response to the rain detection information transmitted from the detection unit 7, the control device 8 executes control to automatically operate a wiper device (not shown) provided on the vehicle 100 when it is raining.

[0050] In the rain detection device 50 configured as shown in FIGS. 1 to 4, the rain detection area on the front windshield 60 is the area between the position where the light emitting element 1 and the light receiving element 2 are provided and the position of the end surface 63.

[0051] 1 to 4, the rain detection area on the windshield 60 is the area between the position where the light-emitting element 1 and the light-receiving element 2 are provided and the position of the edge surface 63, so that the rain detection range can be expanded by simply increasing the distance between the position where the light-emitting element 1 and the light-receiving element 2 are provided and the position of the edge surface 63 of the windshield 60, without increasing the size of the rain detection device 50 itself. Therefore, in the rain detection device 50, the size of the device can be prevented from increasing when the rain detection range is expanded.

[0052] In the rain detection device 50 having the configuration shown in Figs. 1 to 4, the light emitting portion 12 of the light emitting element 1 and the light receiving portion 22 of the light receiving element 2 are arranged to face the same side. As a result, the light emitted from the light emitting portion 12 of the light emitting element 1 is reflected by a reflecting object such as the end surface 63 of the front windshield 60 and is received by the light receiving portion 22 of the light receiving element 2. In this configuration, when the rain detection range of the rain detection device 50 is expanded, it is only necessary to expand the distance between the light emitting element 1 and the light receiving element 2 and the reflecting object such as the end surface 63, and therefore there is no need to expand the distance between the light emitting element 1 and the light receiving element 2. Therefore, in the rain detection device 50, when the rain detection range is expanded, it is possible to suppress an increase in the size of the device.

[0053] Specifically, in the rain detection device 50, the rain detection area on the windshield 60 is the area between the position where the light-emitting element 1 and the light-receiving element 2 are provided and the position of the edge surface 63, so that in order to expand the rain detection range, it is sufficient to increase the distance between the position where the light-emitting element 1 and the light-receiving element 2 are provided and the position of the edge surface 63 of the windshield 60, without increasing the size of the rain detection device 50 itself. Therefore, in the rain detection device 50, when expanding the rain detection range, it is possible to suppress an increase in the size of the device.

[0054] Furthermore, in the rain detection device 50, infrared light L incident on the front window 60 travels while being repeatedly reflected between a first surface 61 in the thickness direction of the front window 60 and a second surface 62 opposite the first surface 61, and is reflected at the end surface 63, so that the range reached by the infrared light L incident on the inside of the front window 60 can be easily expanded.

[0055] Furthermore, in the rain detection device 50, the infrared light L reflected by the end surface 63 of the front window 60 is repeatedly reflected between the first surface 61 in the thickness direction of the front window 60 and the second surface 62 opposite the first surface 61, and travels back toward the light-emitting element, so that the range over which the infrared light L reflected by the end surface 63 of the front window 60 returns can be easily expanded.

[0056] Furthermore, in the rain detection device 50, the light-emitting element 1 and the light-receiving element 2 are arranged side by side in a direction intersecting the direction of the optical axis L0 of the infrared light L emitted by the light-emitting element 1. This eliminates the need to increase the distance between the light-emitting element 1 and the light-receiving element 2 when expanding the rain detection range, thereby preventing the device from becoming larger.

[0057] <Embodiment 2> In the second embodiment, a rain detection device 50A in which a light emitting element 1 and a light receiving element 2 are arranged side by side in the same direction as the optical axis L0 of infrared light L emitted by the light emitting element 1 will be described.

[0058] [Example of configuration of rain detection device 50A] Fig. 5 is a diagram showing the configuration of a rain detection device 50A according to embodiment 2. Fig. 5 shows an enlarged view of the internal configuration of the rain detection device 50A and the surrounding area of ​​the windshield 60 where the rain detection device 50A is provided.

[0059] 5 shows the configuration of the rain detection device 50A and the windshield 60 as viewed from the inside of the windshield 60 of the vehicle 100. In Fig. 5, similar to Fig. 2, in order to clearly show the configuration of the light-emitting element 1 and the light-receiving element 2, the configuration of the rain detection device 50A other than the light-emitting element 1 and the light-receiving element 2 is shown by a simple frame line.

[0060] The rain detection device 50A includes a housing 51A and a sensor body 10A. The rain detection device 50A further includes members similar to the first light guide 41 and the first adhesive material 31 as shown in FIG. 3, and members similar to the second light guide 42 and the second adhesive material 32 as shown in FIG. 3, similar to the rain detection device 50 of FIG. 2. The housing 51A has a shape similar to that of the housing 51 of FIG. 2. The sensor body 10A is provided inside the housing 51A. The sensor body 10A includes a light emitting element 1 and a light receiving element 2 provided on a semiconductor substrate 11A. The configuration of the signal processing circuit related to the rain detection device 50A according to the second embodiment is similar to that of the signal processing circuit of FIG. 4.

[0061] 1 to 4 in that the light-emitting element 1 and the light-receiving element 2 are arranged in series in the same direction as the direction of the optical axis L0 of the infrared light L emitted by the light-emitting portion 12 of the light-emitting element 1. As shown in Fig. 5, the light-receiving element 2 is arranged behind the light-emitting element 1 with respect to the end surface 63 of the front window 60 in the direction in which the light-emitting portion 12 of the light-emitting element 1 emits light.

[0062] In the rain detection device 50A of Fig. 5, similarly to the rain detection device 50 shown in Figs. 1 to 4, infrared light L emitted from the light emitting portion 12 of the light emitting element 1 is incident on the front window 60. Then, similarly to the rain detection device 50 shown in Figs. 1 to 4, inside the front window 60, the infrared light L travels to an end surface 63 of the front window 60 while repeatedly being reflected between a first surface 61 and a second surface 62. In Fig. 5, the light L1 and the light L2 are shown in a positional relationship separated from each other across the optical axis L0 so that the positional relationship with the optical axis L0 does not make the drawing unclear, but in reality, they are located close to each other.

[0063] In the rain detection device 50A of FIG. 5, similarly to the rain detection device 50 shown in FIGS. 1 to 4, inside the front window 60, the infrared light L that travels and enters the end surface 63 is reflected by the end surface 63. Then, light L2, which is light obtained after the light L1 included in the infrared light L is reflected by the end surface 63, returns toward the light-emitting element 1 and the light-receiving element 2 while repeatedly reflecting between the first surface 61 and the second surface 62 inside the front window 60. Thereafter, the light L2 is emitted from inside the front window 60 to the outside and is received by the light-receiving unit 22 of the light-receiving element 2. In the rain detection device 50A, a detection unit similar to the detection unit 7 shown in FIG. 4 performs rain detection processing similar to that of the rain detection device 50 shown in FIGS. 1 to 4.

[0064] In the rain detection device 50A of FIG. 5, the light emitting portion 12 of the light emitting element 1 and the light receiving portion 22 of the light receiving element 2 are arranged to face the same side, similarly to the rain detection device 50. Specifically, in the rain detection device 50A of FIG. 5, unlike the rain detection device 50, the light emitting element 1 and the light receiving element 2 are arranged in series in the same direction as the direction of the optical axis L0 of the infrared light L emitted by the light emitting portion 12 of the light emitting element 1. The light receiving element 2 is provided behind the light emitting element 1 with respect to the end face 63 of the front window 60 in the direction in which the light emitting portion 12 of the light emitting element 1 emits light. In this configuration in which the light receiving element 2 is provided behind the light emitting element 1 with respect to the end face 63 of the front window 60, it is preferable to use an optical configuration that suppresses the light L2 received by the light receiving portion 22 of the light receiving element 2 from being blocked by the light emitting element 1.

[0065] In the rain detection device 50A according to the embodiment 2 described above, for the same reasons as in the rain detection device 50 according to the embodiment 1, when the rain detection range is expanded, an increase in the size of the device can be suppressed.

[0066] Furthermore, in the rain detection device 50A of embodiment 2, the light-emitting element 1 and the light-receiving element 2 are arranged side by side in the same direction as the optical axis L0 of the infrared light L emitted by the light-emitting portion 12 of the light-emitting element 1. This eliminates the need to increase the distance between the light-emitting element 1 and the light-receiving element 2 when expanding the rain detection range, thereby preventing the device from becoming larger.

[0067] Furthermore, in the rain detection device 50A of embodiment 2, the light receiving element 2 is provided behind the light emitting element 1 with respect to the end face 63 of the front window 60 in the direction in which the light emitting portion 12 of the light emitting element 1 emits light, thereby preventing interference between the light emitted by the light emitting portion 12 of the light emitting element 1 and the reflected light received by the light receiving portion 22 of the light receiving element 2.

[0068] Additionally, the rain detection device 50A according to the second embodiment has the same configuration as the rain detection device 50 according to the first embodiment, and can provide the same technical effects as the rain detection device 50.

[0069] <Embodiment 3> In the third embodiment, a rain detection device 50B in which the arrangement of the light-emitting elements 1 is different from that of the rain detection device 50 in the first embodiment will be described.

[0070] [Example of configuration of rain detection device 50B] Fig. 6 is a diagram showing the configuration of a rain detection device 50B according to embodiment 3. Fig. 6 shows an enlarged view of the internal configuration of the rain detection device 50B and the surrounding area of ​​the windshield 60 where the rain detection device 50B is provided.

[0071] 6 shows the configuration of the rain detection device 50B and the windshield 60 as viewed from the inside of the windshield 60 of the vehicle 100. In Fig. 6, similar to Fig. 2, in order to clearly show the configuration of the light-emitting element 1 and the light-receiving element 2, the configuration of the rain detection device 50B other than the light-emitting element 1 and the light-receiving element 2 is shown by a simple frame line.

[0072] The rain detection device 50B includes a housing 51B and a sensor body 10B. The rain detection device 50B further includes members similar to the first light guide 41 and the first adhesive 31 as shown in FIG. 3, and members similar to the second light guide 42 and the second adhesive 32 as shown in FIG. 3, similar to the rain detection device 50 of FIG. 2. The housing 51B has a shape similar to that of the housing 51 of FIG. 2. The sensor body 10B is provided inside the housing 51B. The sensor body 10B includes a light emitting element 1 and a light receiving element 2 provided on a semiconductor substrate 11B. The configuration of the signal processing circuit related to the rain detection device 50B according to the third embodiment is similar to that of the signal processing circuit of FIG. 4.

[0073] In the rain detection device 50B of FIG. 6, the light emitting section 12 of the light emitting element 1 and the light receiving section 22 of the light receiving element 2 are arranged to face the same side. In the example of FIG. 6, both the light emitting section 12 of the light emitting element 1 and the light receiving section 22 of the light receiving element 2 are arranged to face the same side, that is, the side of the rain detection target. The side of the rain detection target is the side of the rain detection area on the windshield 60. The rain detection device 50B of FIG. 6 is different from the rain detection device 50 shown in FIGS. 1 to 4 in that the light emitting element 1 and the light receiving element 2 are arranged so that the optical axis L0 of the infrared light L emitted by the light emitting section 12 of the light emitting element 1 and the optical axis L20 of the light L2 received by the light receiving section 22 of the light receiving element 2 intersect.

[0074] Specifically, in the rain detection device 50B of FIG. 6, compared to the rain detection device 50 shown in FIGS. 1 to 4, the light-emitting element 1 is arranged so that the optical axis L0 of the infrared light L emitted from the light-emitting portion 12 of the light-emitting element 1 is inclined in a direction approaching the light-receiving element 2.

[0075] 1 to 4, in the rain detection device 50B of Fig. 6, infrared light L emitted from the light-emitting portion 12 of the light-emitting element 1 is incident on the front window 60. Then, in the rain detection device 50 shown in Figs. 1 to 4, the infrared light L travels to an end surface 63 of the front window 60 while repeatedly being reflected between a first surface 61 and a second surface 62 inside the front window 60.

[0076] In the rain detection device 50B of Fig. 6, similarly to the rain detection device 50 shown in Figs. 1 to 4, inside the front window 60, the infrared light L that travels and is incident on the end surface 63 is reflected by the end surface 63. Then, the light L2 after the light L1 included in the infrared light L that is incident on the end surface 63 is reflected by the end surface 63 returns toward the light emitting element 1 and the light receiving element 2 while repeatedly being reflected between the first surface 61 and the second surface 62 inside the front window 60. Thereafter, the light L2 is emitted from inside the front window 60 to the outside, and is received by the light receiving unit 22 of the light receiving element 2.

[0077] In FIG. 6, the light L1 included in the infrared light L incident on the end face 63 is reflected by the end face 63 and then received by the light receiving unit 22 of the light receiving element 2 as light L2. FIG. 6 shows an example in which such light L1 is light on the optical axis L0. Note that such light L1 may be light other than the light on the optical axis L0. FIG. 6 shows an example in which the light L2 after reflection on the end face 63 is light on the optical axis L20 of the infrared light L before reflection reflected by the end face 63. Note that such light L2 may be light other than the light on the optical axis L20. In this way, in the rain detection device 50B, the light emitting element 1 and the light receiving element 2 may be arranged so that the optical axis L0 of the infrared light L emitted by the light emitting unit 12 of the light emitting element 1 and the optical axis L20 of the light L2 received by the light receiving unit 22 of the light receiving element 2 intersect.

[0078] In the rain detection device 50B, a detection unit similar to the detection unit 7 shown in FIG. 4 executes rain detection processing similar to that of the rain detection device 50 shown in FIGS.

[0079] In the rain detection device 50B according to the embodiment 3 described above, for the same reasons as in the rain detection device 50 according to the embodiment 1, when the rain detection range is expanded, an increase in the size of the device can be suppressed.

[0080] Additionally, the rain detection device 50B according to the third embodiment has a similar configuration to the rain detection device 50 according to the first embodiment, and can provide the same technical effects as the rain detection device 50.

[0081] <Modifications of the embodiment> Next, a modification of the above-described embodiment will be described.

[0082] (1) Fig. 3(A) shows an example in which the light L1 emitted from the light-emitting section 12 of the light-emitting element 1 passes through the first light guide 41 and enters the inside of the front window 60. However, the present invention is not limited to this example, and the light L1 emitted from the light-emitting section 12 of the light-emitting element 1 may be directly entered into the front window 60 without providing the first light guide 41.

[0083] 3(B) shows an example in which the light L2 reflected by the end surface 63 of the front window 60 passes through the second light guide 42, exits from the front window 60, and is received by the light receiving unit 22 of the light receiving element 2. However, the present invention is not limited to this example, and the light L2 may be reflected by the end surface 63 of the front window 60 and exits from the front window 60 directly received by the light receiving unit 22 of the light receiving element 2 without providing the second light guide 42.

[0084] (3) Fig. 3 shows the rain detection device 50 configured such that the light L1 emitted from the light-emitting unit 12 of the light-emitting element 1 is reflected by an end face 63 of the upper edge of the front window 60, and the light L2 reflected by the end face 63 is received by the light-receiving unit 22 of the light-receiving element 2. However, the rain detection device is not limited to this, and may have a configuration in which the light emitted from the light-emitting unit 12 of the light-emitting element 1 is reflected by an end face of the lower edge of the front window 60, and the light reflected by the end face is received by the light-receiving unit 22 of the light-receiving element 2.

[0085] (4) The end face 63 of the front window 60 shown in Figures 2 and 3 is not basically processed to increase the reflectance of infrared light, but this is not limited thereto, and the end face 63 may basically be processed to increase the reflectance of infrared light.

[0086] <Additional Notes> The present embodiment as described above includes the following technical idea.

[0087] [Configuration 1] A light-emitting element (light-emitting element 1) that emits light from a light-emitting section (light-emitting section 12), a light receiving element (light receiving element 2) capable of receiving, at a light receiving section (light receiving section 22), reflected light that returns to the light emitting element (light emitting element 1) side out of light emitted from the light emitting section (light emitting section 12) of the light emitting element (light emitting element 1); A detection unit (detection unit 7) that detects rain according to light received by the light receiving element (light receiving element 2), A rain detection device (rain detection device 50, 50A, 50B) in which the light emitting portion (light emitting portion 12) of the light emitting element (light emitting element 1) and the light receiving portion (light receiving portion 22) of the light receiving element (light receiving element 2) are arranged facing the same side.

[0088] [Configuration 2] The rain detection device (rain detection device 50, 50A) according to configuration 1, in which the light-emitting element (light-emitting element 1) and the light-receiving element (light-receiving element 2) are arranged so that the direction in which the light-emitting section (light-emitting section 12) of the light-emitting element (light-emitting element 1) emits light is the same as the direction in which the light-receiving section (light-receiving section 22) of the light-receiving element (light-receiving element 2) receives light.

[0089] [Configuration 3] The rain detection device (rain detection device 50B) according to Configuration 1, wherein the light-emitting element (light-emitting element 1) and the light-receiving element (light-receiving element 2) are arranged so that the optical axis (optical axis L0) of light emitted by the light-emitting section (light-emitting section 12) of the light-emitting element (light-emitting element 1) and the optical axis (optical axis L20) of light received by the light-receiving section (light-receiving section 22) of the light-receiving element (light-receiving element 2) intersect.

[0090] [Configuration 4] The light-emitting element (light-emitting element 1) and the light-receiving element (light-receiving element 2) can be attached to a light-transmitting plate-like body (front window 60), the light-emitting element (light-emitting element 1) is provided so as to emit infrared light from the light-emitting portion (light-emitting portion 12), and the infrared light travels inside the plate-like body (front window 60) and is reflected by an end surface (end surface 63) of the plate-like body, The rain detection device (rain detection device 50, 50A, 50B) according to any one of configurations 1 to 3, wherein the light receiving element (light receiving element 2) is arranged so that the infrared light reflected by the end face (end face 63) inside the plate-shaped body (front window 60), returning from the end face (end face 63) toward the light-emitting element (light-emitting element 1), and emitted from the plate-shaped body (front window 60) is received by the light receiving unit (light receiving unit 22).

[0091] [Configuration 5] In the rain detection device (rain detection device 50, 50A, 50B) described in configuration 4, the infrared light incident from the light-emitting element (light-emitting element 1) to the inside of the plate-shaped body (front window 60) travels inside the plate-shaped body (front window 60) while being repeatedly reflected between a first surface (first surface 61) in the thickness direction of the plate-shaped body (front window 60) and a second surface (second surface 62) opposite the first surface (first surface 61), and is reflected by the end surface (end surface 63).

[0092] [Configuration 6] In the rain detection device (rain detection device 50, 50A, 50B) described in Configuration 5, inside the plate-shaped body (front window 60), the infrared light reflected at the end face (end face 63) is repeatedly reflected between the first face (first face 61) and the second face (second face 62) while returning toward the light-emitting element (light-emitting element 1) and is emitted from the plate-shaped body (front window 60).

[0093] [Configuration 7] The plate-shaped body (front window 60) is a front window (front window 60) of a vehicle (vehicle 100), The rain detection device (rain detection device 50, 50A, 50B) according to any one of configurations 4 to 6, wherein the light-emitting element (light-emitting element 1) and the light-receiving element (light-receiving element 2) are provided inside the front window (front window 60).

[0094] [Configuration 8] A rain detection device (rain detection device 50) according to any one of configurations 1 to 5, wherein the light-emitting element (light-emitting element 1) and the light-receiving element (light-receiving element 2) are arranged side by side in a direction intersecting a direction of an optical axis of light emitted by the light-emitting section (light-emitting section 12) of the light-emitting element (light-emitting element 1).

[0095] [Configuration 9] The rain detection device (rain detection device 50A) according to any one of configurations 1 to 8, wherein the light-emitting element (light-emitting element 1) and the light-receiving element (light-receiving element 2) are arranged side by side in the same direction as the optical axis direction of the light emitted by the light-emitting section (light-emitting section 12) of the light-emitting element (light-emitting element 1).

[0096] [Configuration 10] The rain detection device (rain detection device 50A) according to Configuration 9, wherein the light receiving element (light receiving element 2) is provided behind the light emitting element (light emitting element 1) in a direction in which the light emitting portion (light emitting portion 12) of the light emitting element (light emitting element 1) emits light.

[0097] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present disclosure is defined by the claims, not by the description of the embodiments described above, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0098] 1 light emitting element, 2 light receiving element, 12 light emitting section, 22 light receiving section, 7 detection section, 50, 50A, 50B rain detection device, 60 front window, 63 end surface, 61 first surface, 62 second surface, vehicle 100.

Claims

1. A light emitting element that emits light from a light emitting portion; a light receiving element capable of receiving, at a light receiving section, reflected light that has returned to the light emitting element side out of light emitted from the light emitting section of the light emitting element; A detection unit that detects rain in response to light received by the light receiving element, A rain detection device, wherein the light emitting portion of the light emitting element and the light receiving portion of the light receiving element are arranged to face the same side.

2. The rain detection device according to claim 1 , wherein the light emitting element and the light receiving element are arranged so that a direction in which the light emitting portion of the light emitting element emits light and a direction in which the light receiving portion of the light receiving element receives light are the same.

3. 2. The rain detection device according to claim 1, wherein the light-emitting element and the light-receiving element are arranged so that an optical axis of light emitted by the light-emitting portion of the light-emitting element intersects with an optical axis of light received by the light-receiving portion of the light-receiving element.

4. the light emitting element and the light receiving element can be attached to a light-transmitting plate-like body; The light-emitting element is provided so as to emit infrared light from the light-emitting portion, and the infrared light travels inside the plate-like body and is reflected by an end surface of the plate-like body, The light receiving element is arranged so that the infrared light emitted from the plate-like body is reflected at the end surface inside the plate-like body, returned from the end surface toward the light receiving element, and received by the light receiving unit. The rain detection device according to any one of claims 1 to 3.

5. 5. The rain detection device according to claim 4, wherein infrared light incident from the light-emitting element into the inside of the plate-like body travels inside the plate-like body while repeatedly reflecting between a first surface of the plate-like body and a second surface opposite to the first surface, and is reflected by the end surface.

6. 6. The rain detection device according to claim 5, wherein, inside the plate-shaped body, infrared light reflected by the end surface is repeatedly reflected between the first surface and the second surface inside the plate-shaped body, returns toward the light receiving element, and is emitted from the plate-shaped body.

7. the plate-like body is a front window of a vehicle, The rain detection device according to claim 4 , wherein the light emitting element and the light receiving element are provided on an inner side of the windshield.

8. The rain detection device according to any one of claims 1 to 3, wherein the light-emitting element and the light-receiving element are arranged side by side in a direction intersecting a direction in which the light-emitting portion of the light-emitting element emits light.

9. The rain detection device according to any one of claims 1 to 3, wherein the light-emitting element and the light-receiving element are arranged side by side in a direction in which the light-emitting portion of the light-emitting element emits light.

10. The rain detection device according to claim 9 , wherein the light receiving element is provided behind the light emitting element in a direction in which the light emitting portion of the light emitting element emits light.

Images