JPH0628715U - Raindrop sensor - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a raindrop sensor that can be easily mounted without requiring waterproof treatment. [Structure] The raindrop detection light α1 incident from the rear surface 10b of the glass 10 on the front surface 10a side of the glass 10 is used as a raindrop detection point 5
A raindrop sensor 1 including a reflecting member 5 having an uneven surface 5b for reflecting at b3.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a raindrop sensor that is used to automatically detect a skylight of a house or a wiper of an automobile by detecting rain.

[0002]

[Prior art]

 Conventionally, as a raindrop sensor for automatically driving a wiper upon detecting that it is raining, for example, there is one disclosed in Japanese Utility Model Laid-Open No. 60-150475.

The raindrop sensor described in the above publication is arranged in a portion such as an automobile hood where a raindrop easily hits, and is charged by a vibration element that generates a voltage due to collision of the raindrop and a voltage from the vibration element. In addition, a control circuit that supplies a current to the drive circuit of the wiper when the charging potential reaches a predetermined value is provided.

[0004]

[Problems to be solved by the device]

 In the conventional raindrop sensor described above, it is installed on the outer panel of the automobile or on the glass surface in order to collide with raindrops, so it is necessary to carry out waterproof treatment so that rain and water do not enter inside, and as a result, the external shape is Since there is a possibility that it will become large and it will protrude from the vehicle body when the outer shape becomes large, there is a problem that the position is limited and it cannot be easily installed, and these problems can be solved. It was an issue.

[0005]

[The purpose of the device]

 The raindrop sensor according to the present invention aims to provide a raindrop sensor which does not need to be waterproofed and can be easily mounted.

[0006]

[Constitution of device]

[0007]

[Means for Solving the Problems]

 A raindrop sensor according to the present invention includes a light emitting element that emits raindrop detection light on the back surface of glass, and a raindrop detection light level that has passed through the glass on the back surface of the glass and is adjusted to the level of the raindrop detection light. A light receiving element for generating a corresponding detection signal, a control unit for amplifying and controlling the detection signal from the light receiving element, and an uneven surface for reflecting raindrop detection light incident from the backside of the glass on the front side of the glass at the raindrop detection point In a preferred embodiment, the incident angle of the light for raindrop detection from the light emitting element is determined by the critical angle of the light traveling from the reflecting member into the air. And the apex angle of the uneven surface having an angle within the range of the critical angle of the light traveling from the reflecting member into the raindrop.

[0008]

[Function of the device]

 In the raindrop sensor according to the present invention, the raindrop detection light that is generated on the back surface of the glass and that is transmitted from the light emitting element through the glass is reflected by the uneven surface of the reflecting portion and travels toward the light receiving element on the back surface of the glass. At this time, the level detected by the light receiving element is high. When a raindrop adheres to the raindrop detection point, the raindrop detection light from the light emitting element is divided into light that passes through the reflector and enters the raindrop and light that is reflected by the reflector and travels toward the light receiving element. Therefore, the level detected by the light receiving element becomes low and the fact that it is raining is detected on the back surface of the glass.

[0009]

【Example】

 1 and 2 show an embodiment of a raindrop sensor according to the present invention.

The illustrated raindrop sensor 1 includes a light emitting element 2 and a light receiving element 3 arranged near a back surface 10 b of a glass 10 (window glass), a control section 4 electrically connected to the light receiving element 3, and a glass 10. The reflecting member 5 is in close contact with the surface 10a of the.

The light emitting element 2 arranged near the back surface 10b of the glass 10 emits raindrop detection light α 1 from the radiation portion 2c by supplying a predetermined current to the external wirings 2a 1 and 2b. It is an infrared light emitting diode, and the raindrop detecting light α1 is made incident from a direction directly intersecting the back surface 10b of the glass 10.

Further, the light receiving element 3 arranged near the back surface 10b of the glass 10 is close to the light emitting element 2 and excites electrons corresponding to the energy of the light with which the light receiving section 3a is irradiated. The photodiodes are output from the external wirings 3b and 3c, and the raindrop detecting light α1 is emitted from a direction orthogonal to the back surface 10b of the glass 10.

The input side of the control unit 4 is electrically connected to the external wirings 3b and 3c of the light receiving element 3, and the control unit 4 amplifies and shapes the output current from the light receiving element 3 and is preset. When the shaped level becomes smaller than the threshold level, it is recognized that it is raining and the wiper operating current is output from the output wirings 4a and 4b. The wiper operating current operates a wiper (not shown) via a drive circuit (not shown).

On the other hand, the reflecting member 5 that is in close contact with the surface 10a of the glass 10 is a medium having a density higher than that of air and raindrops (water), is formed of a glass material, and has a refractive index of It is set to 1.5.

The reflecting member 5 is provided with a smooth surface 5a, which is in close contact with the surface 10a of the glass 10, on one side, and an uneven surface 5b on the other side opposite to the smooth surface 5a.

The concavo-convex surface 5b is formed as a first reflection surface 5b1 and a second reflection surface 5b2 which are continuous along the smooth surface 5a with a vertical angle θ1 interposed.

Since the raindrop detection light α1 from the light emitting element 2 has an incident angle that is orthogonal to the back surface 10b of the glass 10, the incident angle that is also orthogonal to the smooth surface 5a of the reflecting member 5. And has an incident angle r1 with respect to the normal line of the first reflection surface 5b1 toward the raindrop detection point 5b3 inside the first reflection surface 5b1.

Here, the magnitude of the apex angle θ1 is determined by changing the incident angle r1 of the raindrop detection light α1 incident on the first reflecting surface 5b1 from an optically dense medium (glass) to an optically sparse medium (glass). When light travels from an optically dense medium (glass) that is larger than the critical angle (about 41 °) when the light travels to air) to an optically sparse medium (water) (refractive index 1.33) Is set to a value smaller than the critical angle (about 62 °) of, and the incident angle r2 of the raindrop detection light α1 incident on the second reflecting surface 5b2 after being reflected by the first reflecting surface 5b1 is It is set to be in the same range as.

As a result, the incident angle r1 of the raindrop detecting light α1 incident on the first reflecting surface 5b1 and the incident angle r2 of the raindrop detecting light α1 incident on the second reflecting surface 5b2 are about 41 ° to about 62 °. Since the apex angle θ1 is set so as to fall within the range of, the reflectance on the uneven surface 5b of the reflecting member 5 is 100% when the incident angle r1 with respect to air is larger than about 41 ° (total Reflection), and 100% (total reflection) does not occur unless the incident angle r1 with respect to raindrops is larger than about 62 °.

The raindrop sensor 1 having such a structure is for detecting raindrops emitted from the light emitting element 2 when rain is not present as shown in FIG. 1 with a main switch (not shown) turned on and off. The light α1 passes through the glass 10 and enters the first reflecting surface 5b1 of the uneven surface 5b provided on the reflecting member 5 at an incident angle r1.

Since the incident angle r1 is set by the apex angle θ1 so as to be larger than the critical angle of the light traveling from the reflecting member 5 into the air, for detecting raindrops incident on the first reflecting surface 5b1. The light α1 is totally reflected by the first reflecting surface 5b1 and travels toward the second reflecting surface 5b2.

Since the incident angle r2 at which the raindrop detection light α1 is incident on the second reflection surface 5b2 is set in the same manner as above by the apex angle θ1, the raindrop detection light α 1 incident on the second reflection surface 5b2 is The light is totally reflected by the second reflecting surface 5b2 and goes toward the light receiving element 3.

As a result, the raindrop detection light α1 from the light emitting element 2 is totally reflected by the first reflecting surface 5b1 and is also totally reflected by the second reflecting surface 5b2 toward the light receiving element 3; A large output current is generated, and the wiper operating current is not output by the controller 4.

In this state, it begins to rain, and as shown in FIG. 2, when the raindrop 20 adheres to the raindrop detection point 5b3 of the uneven surface 5b provided on the reflection member 5, it is incident on the first reflection surface 5b1. The incident angle r1 of the raindrop detecting light α1 is set by the apex angle θ1 so as to be smaller than the critical angle of the light traveling from the reflecting member 5 into the raindrop. Therefore, the raindrop incident on the first reflecting surface 5b1 is The detection light α1 is reflected by the light α2 refracted into the raindrop 20 at a refraction angle θ2 with respect to the first reflection surface 5b1 and the reflection angle θ3 with respect to the normal line of the first reflection surface 5b1 and then reflected by the second reflection surface 5b2. The light is dispersed toward the light α3.

At this time, the amount of light α3 reflected by the first reflection surface 5b1 at the reflection angle θ3 and traveling toward the second reflection surface 5b2 is greater than the amount of light α2 refracted into the raindrop 20 at the refraction angle θ2. Remarkably less.

The light α3 incident on the second reflecting surface 5b2 at the incident angle r2 is an apex angle θ so that the incident angle r2 is smaller than the critical angle of the light traveling from the reflecting member 5 into the raindrop. 1 is set, the light α4 refracted into the raindrop 20 at a refraction angle θ4 with respect to the second reflection surface 5b2 and the light α5 reflected at a reflection angle θ5 with respect to the normal line of the second reflection surface 5b2. The light receiving element 3 is irradiated with only the light α5 which is dispersed into the second reflection surface 5b2 and is reflected by the reflection angle θ5.

As a result, when the raindrop 20 adheres to the raindrop detection point 5b3, only the light α5 reflected at the reflection angle θ5 on the second reflection surface 5b2 is detected by the light receiving element 3, so that the light receiving element 3 A small output current is generated due to the difference in light amount between the light α5 and the raindrop detection light α1, and the level amplified and shaped by the control unit 4 becomes smaller than the threshold level, so that it started to rain. After that, the wiper operating current is output, and the wiper operating current is used to operate the wiper.

When the raindrops stop and the raindrops 20 no longer adhere to the raindrop detection points 5b3, the amount of light applied to the light receiving element 3 increases as shown in FIG. 1, so that the wiper operating current is The output is stopped and the wiper operation is stopped.

Although the raindrop sensor according to the embodiment of the present invention is used for operating the wiper, the operation current from the control unit 4 is used to open and close the skylight of the house. May be.

[0030]

[Effect of device]

 As described above, since the present invention is configured as described above, it is possible to detect that it is raining on the back surface of the glass, so that it is not necessary to apply waterproof treatment and the position is limited. It has an excellent effect that it can be installed easily because it does not need to be installed.

[Brief description of drawings]

FIG. 1 is a schematic view of an embodiment of a raindrop sensor according to the present invention.

FIG. 2 is a schematic diagram when the raindrop sensor shown in FIG. 1 detects raindrops.

[Explanation of symbols]

 1 Raindrop Sensor 2 Light-Emitting Element 3 Light-Receiving Element 4 Control Section 5 Reflecting Member 5b Uneven Surface 5b3 Raindrop Detection Point 10 Glass 10a Front Surface 10b Backside α1 Raindrop Detection Light

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical indication location G01N 21/41 Z 7370-2J (72) Creator Kunihiko Kanda Higashimatano-cho, Totsuka-ku, Yokohama-shi, Kanagawa 1760 Automobile Industry Co., Ltd.

Claims (2)

[Scope of utility model registration request] 1. A light emitting element for generating raindrop detection light on the back surface of the glass, and a detection signal corresponding to the level of the raindrop detection light upon receiving the raindrop detection light transmitted through the glass on the back surface of the glass. A light receiving element that generates a light, a control unit that controls amplification of a detection signal from the light receiving element, and an uneven surface that reflects raindrop detection light incident from the back surface of the glass at the raindrop detection point is formed on the front surface side of the glass. A raindrop sensor comprising a reflecting member. 2. The angle of incidence of the raindrop detection light from the light emitting element is such that it falls within the range between the critical angle of the light traveling from the reflecting member into the air and the critical angle of the light traveling from the reflecting member into the raindrop. The raindrop sensor according to claim 1, wherein the raindrop sensor is set by the apex angle of the uneven surface having the.