JP2000193586A - Optical raindrop detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a raindrop detector capable of detecting a raindrop at a low cost. SOLUTION: In the optical raindrop detector, a light emitting diode 33 is inserted in the recessed part 39 of a prism 3 on a light emitting side and the light L diffused from the light emitting diode 33 is refracted toward a slope 44 by the circular arc surface of the prism 38 on the light emitting side and this light L is incident on a front window 2 from the incident region IA set to an inside surface 3 and totally reflected by the reflecting region HA set to the reflection position reflected at first by an outside surface 51. A photodiode 61 is inserted in the recessed part 66 formed on the circular arc surface of a prism 65 on a light detecting side and the light L incident on the prism 65 on the light receiving side from a slope 72 is refracted by a circular arc surface 71 to be condensed to the photodiode 61. The slope 72 of the prism 65 on the light detecting side is arranged to the output region OA set to the position where the light L reflected at first by the reflecting region HA is outputted to the outside from the interior of the front window 2 and the photodiode 61 detects only the once reflected light of the light L in the front window 2 in the reflecting region HA.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical raindrop detecting device for optically detecting raindrops attached to a window.

[0002]

2. Description of the Related Art Conventionally, a vehicle is provided with an optical raindrop detecting device 501 as shown in FIG.
505101).

The optical raindrop detecting device 501 includes a light emitting diode 512 for emitting a radiation beam 511, a first deflecting mirror 513 for reflecting the radiation beam 511 emitted from the light emitting diode 512, and a first deflecting mirror. First prism 515 for guiding radiation beam 511 reflected by mirror 513 to window glass 514 at a predetermined angle
And an outer surface 516 and an inner surface 517 of the window glass 514.
A second prism 518 for receiving the radiation beam 511 reflected a plurality of times therebetween, a second deflection mirror 519 for reflecting the radiation beam 511 incident by the second prism 518 at a predetermined angle, A photodiode 521 that receives the radiation beam 511 reflected by the second deflection mirror 519 via a stop 520; In addition, the optical raindrop detection device 501 includes:
An electronic control measurement circuit 522 for comparing and controlling the light quantity of the radiation beam 511 received by the photodiode 521 and the light quantity of the radiation beam 511 emitted by the light emitting diode 512 is provided.

Accordingly, the measurement section 541 of the window glass 514 in which the radiation beam 511 is reflected a plurality of times between the outer surface 516 and the inner surface 517 of the window glass 514 and passes therethrough.
In the electronic control measurement circuit 522, it is confirmed that a part of the radiation beam 511 is emitted from the outer side surface 516 of the window glass 514 due to the attachment of the raindrop 531 and the light receiving intensity in the photodiode 521 is attenuated. If this is detected and the intensity is equal to or less than the intensity limit value, it is determined that the raindrop 531 has adhered to the window glass 514.

[0005]

However, in the above-mentioned optical raindrop detecting device 501, the window glass 51 is provided.
The attachment state of the raindrop 531 to the window glass 514 is determined by the radiation beam 511 that has been reflected a plurality of times between the outer surface 516 and the inner surface 517 in the inside 4. Therefore, when water droplets generated by dew condensation adhere to the inner side surface 517 of the window glass 514, the water droplets 511 are generated by the water droplets.
Is released from the inner surface 517 of the window glass 514,
The amount of light received by the photodiode 521 is reduced, and it may be erroneously determined that the raindrop 531 has adhered to the window glass 514.

In order to prevent such a problem, the optical raindrop detecting device 501 uses the radiation beam 511.
However, a heating device 542 for heating and drying the measurement section 541 through which the light is repeatedly reflected a plurality of times is indispensable, which has been a factor of high cost.

The present invention has been made in view of such conventional problems, and has as its object to provide an optical raindrop detecting device capable of detecting raindrops at low cost. .

[0008]

In order to solve the above-mentioned problems, an optical raindrop detecting device according to the present invention has a light-emitting means for emitting a light beam entering the inside of the glass from the inner surface of the glass. In the optical raindrop detecting device having light receiving means for reflecting a light beam incident on the inside of the glass on an outer surface of the glass and receiving the reflected light on the inner surface, The light receiving means is provided at a position where the incident light beam is first reflected on the outer surface and the reflected light reaches the inner surface.

That is, since the light emitted from the light emitting means is reflected only once on the outer surface of the glass, the influence of dew condensation on the inner surface is excluded.

A light emitting side prism for guiding the light emitted from the light emitting means toward the glass is provided between the light emitting means and the inner surface of the glass. A light receiving side prism for guiding the light beam toward the light receiving means is provided between the light receiving side prism and the side surface.

As a result, the influence of disturbance light such as direct sunlight is prevented.

Further, the end face of the light emitting side prism provided with the light emitting means on the light emitting means side is formed in an arc shape so as to refract the light emitted and diffused by the light emitting means toward the glass side. Along with the light receiving means side end face of the light receiving side prism provided with the light receiving means,
The light beam incident from the inner side surface of the glass was formed in an arc shape so as to be focused on the light receiving means.

That is, since the light beam emitted and diffused by the light emitting means is refracted toward the glass side by the end face of the light emitting side prism formed in an arc shape, the irradiation area of the light beam on the glass side is as follows. It is extended in the length direction of the end face. Further, since the light beam incident on the light receiving side prism is condensed on the light receiving means by the end face formed in an arc shape, the light condensing area by the light receiving means is extended in the length direction of the end face. Thereby, even if the number of times of reflection of the light beam on the outer surface is only one, the area (measurement section) where the light beam is reflected is expanded.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment of the present invention will be described below with reference to the drawings. FIG.
1 is a cross-sectional view showing an optical raindrop detecting device 1 according to the present embodiment, showing a state where the optical raindrop detecting device 1 is attached to an inner surface 3 of a front window 2 as glass in a vehicle.

The housing 1 of the optical raindrop detecting device 1
1, a main body component 12 that opens to the front window 2 side is housed in a state of being fitted therein, and a close contact with the front window 2 is provided between the main body component 12 and the housing 11. A sealing material 13 is provided. A concave portion 14 is formed over the entire circumference between the sealing member 13 and the main body constituting member 12, and an adhesive 15 is provided between the concave portion 14 and the inner surface 3 of the front window 2. Is filled, and the optical raindrop detecting device 1 is fixed to the vehicle room I side of the front window 2.

A shield member having a T-shaped cross section, comprising a flat plate portion 21 extending along the front window 2 and an upright wall 22 erected at the center of the flat plate portion 21 is provided on the main body constituent member 12. 23 are provided. The shielding member 23
The upright wall 22 is sandwiched between a pair of sandwiching pieces 24, 24 protruding from a central portion of the main body constituting member 12, and the flat plate portion 21 is formed at an edge of the main body constituting member 12. It is fixed while being locked to the inner flange portion 25. Thereby, the inside of the main body component member 12 is in the first chamber 2 shielded from each other by the upright wall 22.
6 and a second chamber 27.

The main body member 12 has a first inclined surface 31 formed on a side wall on the first chamber 26 side, and a second inclined surface formed on a side wall on the second chamber 27 side. 32 are formed. A first holder 34 holding a light emitting diode 33 as a light emitting means is fixed to the first inclined surface 31 in a state where the first holder 34 is inserted, and a harness extending from a base end of the first holder 34 is provided. Reference numeral 35 is connected to a control device (not shown) via a rubber bush 36 provided on the housing 11. The light emitting diode 3
A lens portion 37 is formed at the tip of 3, and the lens portion 37 is inserted into a concave portion 39 of the light-emitting side prism 38.

The light emitting side prism 38 is shown in FIGS.
Is formed in a semicircular plate shape, and is provided to be inclined with respect to the glass 43 provided in parallel with the front window 2. The glass 4
Reference numeral 3 denotes a peripheral edge placed on the inner flange portion 25 of the main body constituent member 12 (see FIG. 1). The concave portion 39 is formed at the center of an arc surface 42 forming one end surface which is an end surface on the light emitting means side of the light emitting side prism 38, and is formed at the other end of the light emitting side prism 38 facing the arc surface 42. Is
The glass 43 and a slope 44 that is in close contact with the front window 2 are formed via a colorless and transparent silicon sheet 41 having the same transmittance (refractive index 1.6) as the glass 43.

Thus, as shown in FIG. 3, the light beams L,...
Is refracted toward the inclined surface 44 by the arc surface 42 and can be irradiated toward the inclined surface 44, and thereby, the light emitting diode 33 as a light emitting means is provided.
The light rays L,... That are further emitted and diffused are guided toward the front window 2 as glass. As shown in FIG. 1, an incident area IA through which the light beam L enters the inside of the front window 2 via the glass 43 and the silicon sheet 41 is formed on the inner surface 3 of the front window 2. Is set. In the light-emitting side prism 38, the case where the one end face for reflecting the light beam L is constituted by the arc surface 42 is described as an example, but may be constituted by an arc-shaped reflector. The angle of incidence of the light beam L on the front window 2 is determined by the light beam L incident on the inside of the front window 2.
Is totally reflected in the reflection area HA, which is a reflection position where the light is first reflected on the outer surface 51 of the front window 2 (the angle α on the incident side with respect to the perpendicular V of the front window 2 and the angle α on the reflection side are different). 45 ° or more), and the inclination angle of the light emitting side prism 38 with respect to the front window 2 is set correspondingly.

As shown in FIG. 1, the second chamber 2
A second holder 62 holding a photodiode 61 as a light receiving means is fixed to the second inclined surface 32 on the 7 side while being inserted, and extends from the base end of the second holder 62. The harness 63 is connected to the rubber bush 36.
Is connected to a control device (not shown) via the. At the tip of the photodiode 61, a lens portion 64 is formed.
6 is inserted.

The light receiving side prism 65 is shown in FIGS.
As shown in FIG. 1, similarly to the light emitting side prism 38, the light emitting prism 38 is formed in a semicircular plate shape, and is provided to be inclined with respect to the glass 43 of the main body constituting member 12 (FIG. 1).
reference). The concave portion 66 of the light-receiving side prism 65 is formed at the center of an arc-shaped surface 71 forming one end surface of the light-receiving side prism 65 which is an end surface on the light-receiving means side.
On the other end of the light-receiving side prism 65 facing the light-receiving side 1, a slope 72 is formed which is in close contact with the front window 2 via the glass 43 and the silicon sheet 41. The light-receiving side prism 65 is a light beam L first reflected in the reflection area HA of the front window 2.
Is provided through the silicon sheet 41 and the glass 43 at a position where the light can enter from the slope 72, and the inner surface 3 of the front window 2 where the slope 72 is located, is provided with the light L. 2, an output area OA to be output from the inside to the outside is set. The position of this output area OA is the position of the front window 2
This is a position where the reflected light from the reflection area HA where the light beam L incident inside is first reflected on the outer surface 51 of the front window 2 reaches the inner surface 71 of the front window 2. Thus, the photodiode 61 of the light receiving means is configured to receive only one reflection of the light beam L on the outer surface 51 of the front window 2 in the reflection area HA.

The angle of inclination of the light-receiving side prism 65 with respect to the front window 2 is determined by the angle of reflection of the light ray L reflected from the front window 2 (the angle of incidence on the perpendicular V of the front window 2 and the angle of reflection on each side). (The angle α is 45 degrees or more), and is configured so that disturbance light such as direct sunlight does not enter. The light receiving side prism 65 is configured so that the light beam L diffused over a wide range is refracted by the arc surface 71 and condensed on the photodiode 61. In addition, in the light receiving side prism 65, the case where the one end face for reflecting the light beam L is constituted by the arc surface 71 has been described as an example, but may be constituted by an arc reflector.

In this embodiment having the above-described configuration, the light beam L emitted from the light emitting diode 33 is reflected only once in the reflection area HA which is the first reflection position set on the outer surface 51 of the front window 2. Is done. Therefore, when the raindrop R adheres to the outer surface 51, the light ray L
Part of the front window 2 due to the raindrop R
Since the light is emitted to the outside and the amount of light received by the photodiode 61 is reduced, it is possible to detect the attachment of the raindrop R as before. On the other hand, the light ray L passing through the front window 2 is received by the photodiode 61 without being reflected by the inner surface 3 at all, so that the inner surface 3 of the front window 2 on the side of the passenger compartment I. When water droplets adhere to the inner surface 3 due to dew condensation, the influence on the detection result by the photodiode 61 due to this can be excluded.

Therefore, in order to prevent the dew condensation on the inner surface 3 of the front window 2 as in a structure in which the light ray L is reflected a plurality of times between the outer surface 51 and the inner surface 3 of the front window 2. In addition, compared with the related art in which a heating device must be provided in a measurement section through which the light beam L passes, a drying structure such as a heating device and an airtight structure is not required, and the structure can be simplified and the cost can be reduced. it can. Further, since it is not necessary to secure an area (measurement section) for reflecting the light beam L a plurality of times, the light emitting diode 33 is not required.
And the light emitting side prism 38 and the photodiode 61
And the distance from the light receiving side prism 65 can be reduced,
The size can be reduced.

Further, the light beam L is transmitted with a low transmittance (50% to 50%).
80%) Outer surface 51 and inner surface 3 of front window 2
The amount of light decreases due to multiple reflections between
In order to compensate for this, the optical path of the light beam L can be shortened and the amplification factor after light reception can be reduced as compared with the conventional case where the amplification factor after light reception must be increased to compensate for this. Can be enhanced.

The light emitting diode 33 is provided between the light emitting diode 33 and the front window 2.
The light emitting side prism 38 for guiding the light beam L emitted from the light source to the reflection area HA is provided, and the light ray L reflected from the reflection area HA is provided between the photodiode 61 and the front window 2. Is provided to the photodiode 61, the influence of disturbance light such as direct sunlight can be prevented, and the malfunction prevention effect can be enhanced.

Further, the light emitting side prism 38 is formed in a semicircular plate shape,
Is inserted into a concave portion 39 provided at the center of the arc surface 42. For this reason, the light L diffused by the light emitting diode 33 can be refracted toward the inclined surface 44 by the arc surface 42 of the light emitting side prism 38 as shown in FIG. Irradiation area,
The arc surface 42 can be expanded in the length direction. The light-receiving side prism 65 is also formed in a semicircular plate shape, and the photodiode 61 has an arc surface 7.
1 is inserted into a concave portion 66 provided at the center. Therefore, the light beam L incident from the inclined surface 72 of the light receiving side prism 65 can be condensed on the photodiode 61 by the arc surface 71. Thus, the light condensing area of the photodiode 61 can be extended in the length direction of the arc surface 71. Then, by combining these prisms 38 and 65, the detection range of the raindrop R is expanded to the width dimension of each of the prisms 38 and 65 even if the light L is reflected only once on the outer surface 51. Therefore, the detection accuracy of the raindrop R can be improved.

(Second Embodiment) FIG. 4 is a view showing a second embodiment of the present invention, wherein the photodiode 61 in the first embodiment is replaced by a planar light receiving element 101. FIG. An optical raindrop detector 102 is shown. Further, the light emitting side prism 38 and the light receiving side prism 65
Is covered with a reflective coating 103.

As a result, it is possible to prevent the light ray L passing through the light-emitting side prism 38 from leaking to the outside, and to prevent the disturbance light from entering the light-receiving side prism 65, thereby reducing noise. The optical raindrop detecting device 102 can be a strong device.

(Third Embodiment) FIG. 5 is a view showing a third embodiment of the present invention. The light receiving side prism 65 in the first embodiment is parallel to the light emitting side prism 38. An optical raindrop detecting device 111 provided is shown. In the optical raindrop detecting device 111, the light beam L first reflected (once reflected) at the front window 2
However, a plurality of reflections are repeated in the light receiving side prism 65 and reach the photodiode 61.

In the optical raindrop detecting device 111, the size can be further reduced by providing the two prisms 38 and 65 in parallel.

(Fourth Embodiment) FIGS. 6A and 6B are diagrams showing a fourth embodiment of the present invention.
The light-emitting side prism 38 and the light-receiving side prism 65 according to the first embodiment include a light-emitting side and a light-receiving side convex lens 121,
An optical raindrop detector 123 formed by 122 is shown.

Thus, the light beam L emitted and diffused by the light emitting diode 33 is converted into a wide parallel light beam by the light emitting side convex lens 121 and then condensed on the photodiode 61 by the light receiving side convex lens 122. It is configured.

(Fifth Embodiment) FIG. 7A is a view showing a fifth embodiment of the present invention, in which a light emitting side prism 38 and a light receiving side prism 65 according to the first embodiment are shown.
Are abolished, and a plurality of light emitting diodes 131,.
Shown is an optical raindrop detector 133 constituted by a plurality of photodiodes 132,... Corresponding to the respective light emitting diodes 131,.

Thus, the area for detecting raindrops can be increased.

(Sixth Embodiment) An optical raindrop detector 141 according to a sixth embodiment shown in FIG. 7B.
As described above, one light emitting diode 142 and the light beam L emitted and diffused from the light emitting diode 142 may be received by a plurality of arranged photodiodes 143.

In this case, since a single light emitting diode 142 can realize a wide detection area, the cost can be reduced as compared with the optical raindrop detection device 133 of the fifth embodiment.

[0038]

As described above, in the optical raindrop detecting device of the present invention, the light emitted from the light emitting means is:
Since the light is reflected only once on the outer surface (reflection area) of the glass, the detection of raindrops attached to the outer surface can be performed as usual, and the influence on the detection result due to condensation on the inner surface can be excluded. it can. Therefore, in order to prevent the occurrence of dew condensation on the inner surface of the glass, such as a structure in which the light beam is reflected multiple times between the outer surface and the inner surface of the glass, the measurement section through which the light passes is heated. Compared with the conventional case where the apparatus has to be provided, a drying structure such as a heating device and an airtight structure is not required, and the structure can be simplified and the cost can be reduced. In addition, since it is not necessary to secure an area (measurement section) for reflecting the light beam a plurality of times, the distance between the light emitting unit and the light receiving unit can be reduced, which can contribute to downsizing.

Further, the amount of light is reduced by reflecting the light beam a plurality of times between the outer surface and the inner surface of the glass, and the amplification factor after receiving the light must be increased to compensate for this. As a result, the light path of the light beam is short and the amplification factor after light reception can be reduced, so that the noise resistance can be improved.

Further, by providing a light-emitting side prism and a light-receiving side prism for guiding a passing light beam between the light emitting means and the glass and between the light receiving means and the glass, the influence of disturbance light such as direct sunlight is provided. Can be prevented, and the malfunction prevention effect can be enhanced.

Further, the light emitted and diffused by the light emitting means is refracted toward the glass side by the end face of the light emitting side prism formed in an arc shape, so that the irradiation area of the light ray on the glass is reduced. Can be extended in the longitudinal direction. Further, the light beam incident on the light receiving side prism is condensed on the light receiving means by an end face formed in an arc shape, so that a light condensing area by the light receiving means is extended in a length direction of the end face. Can be. By combining these, even if the number of reflections on the outer surface of the light beam is only one, the region (measurement section) where the light beam is reflected can be expanded in the length direction of the end face of each prism. As a result, the detection accuracy of raindrops can be improved.

[0042]

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of the present invention.

FIG. 2 is a schematic perspective view showing the embodiment.

FIG. 3 is a schematic plan view showing the same embodiment.

FIG. 4 is a sectional view showing a second embodiment of the present invention.

FIG. 5 is a sectional view showing a third embodiment of the present invention.

FIG. 6A is a diagram showing a main part of a fourth embodiment of the present invention, and FIG. 6B is a schematic diagram showing the same embodiment.

FIG. 7A is a schematic diagram showing a fifth embodiment of the present invention, and FIG. 7B is a schematic diagram showing a sixth embodiment of the present invention.

FIG. 8 is a sectional view showing a conventional optical raindrop detecting device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical raindrop detector 2 Front window 3 Inner surface 33 Light emitting diode (light emitting means) 38 Light emitting side prism 42 Arc surface (one end surface) 51 Outer surface 61 Photodiode (light receiving unit) 65 Light receiving side prism 71 Arc surface (one end surface) ) 101 light receiving element (light receiving means) 102 optical raindrop detecting device 111 optical raindrop detecting device 121 light emitting side convex lens 122 light receiving side convex lens 123 optical raindrop detecting device 131 light emitting diode (light emitting means) 132 photodiode (light receiving means) 133 optical Rain detector 141 Optical rain detector 142 Light emitting diode (light emitting means) 143 Photo diode (light receiving means) L ray HA Reflection area IA Incident area OA Output area

Claims (3)

[Claims] 1. A light emitting means for emitting a light beam incident on the inside of the glass from an inner surface of the glass, wherein the light beam incident on the inside of the glass is reflected on an outer surface of the glass, and An optical raindrop detecting device having light receiving means for receiving the reflected light beam on the inner surface, wherein the light beam incident on the inside of the glass is first reflected on the outer surface, and the reflected light is reflected on the inner surface. An optical raindrop detecting device, wherein the light receiving means is provided at a position where the raindrop reaches. 2. A light-emitting side prism for guiding the light beam emitted from the light-emitting means toward the glass is provided between the light-emitting means and the inner surface of the glass, and the light-receiving means and the inside of the glass are provided. The optical raindrop detecting device according to claim 1, further comprising a light receiving side prism that guides the light beam toward the light receiving unit between the light receiving unit and the side surface. 3. An end face on a light emitting means side of the light emitting side prism provided with the light emitting means is formed in an arc shape so as to refract the light beam emitted and diffused by the light emitting means toward the glass side. A light receiving means side end face of the light receiving side prism provided with the light receiving means is formed in an arc shape so as to converge the light beam incident from the inner surface of the glass to the light receiving means. The optical raindrop detecting device according to claim 2, wherein