JPH08261933A - Deposit detecting device for glass - Google Patents

Abstract

PURPOSE: To provide a deposit detecting device for glass capable of accurately discriminating raindrops and stains with a simple structure. CONSTITUTION: A light emitting means 10 and a light receiving means are arranged so that the light from the light emitting means 10 reaches the light receiving means after transmitting glass, and the stuck state of raindrops and stains on the glass surface is detected based on the detection quantity of the light from the light emitting means 10 by the light receiving means. The light emitting means 10 averagely emits the light in the wide-range wavelength band including the water absorbing wavelength. The light receiving means is constituted of the first light receiving element 11 limitedly detecting the light of mainly the water absorbing wavelength and the second light receiving element 12 limitedly detecting the light of the water nonabsorbing wavelength in the wavelength band of the light emitted from the light emitting means 10. The first light receiving element 11 is a photo-diode made of Ge, and the second light receiving element 12 is a photo-diode made of GaAs in particular.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass adhering matter detecting device for detecting the adhering state of raindrops or dirt adhering to the glass surface.

[0002]

2. Description of the Related Art Conventionally, a light emitting means and a light receiving means are arranged so that the light from the light emitting means reaches the light receiving means after passing through the glass, and based on the detection amount of the light from the light emitting means in the light receiving means. There is a known glass adhering matter detection device that detects the adhering state of raindrops and dirt on the glass surface, and is used for wiper control in vehicles. According to this, since the operation of the wiper for wiping off the adhering matter is automated, a troublesome switch operation is not necessary and the wiper can be effectively operated, which is advantageous in improving convenience and safety.

An example of such a glass adhering matter detection device is to detect the amount of raindrops from the amount of light transmitted at a specific wavelength (hereinafter referred to as a water absorption wavelength) having a characteristic of being easily absorbed by water. (Japanese Patent Laid-Open No. 58-1
See Japanese Patent No. 56439). Further, there is a method in which raindrops and dirt are discriminated from the respective detection amounts of a plurality of light receiving elements by utilizing the effect of condensing raindrops and the effect of shielding dirt (see JP-A-57-186556). .

[0004]

However, in the above-mentioned adhering substance detecting device using the water absorption wavelength light, in addition to the water absorption wavelength light, a wavelength that is difficult to be absorbed by water (hereinafter referred to as a non-water absorption wavelength). Light is used, but it is only used as a comparison target when calculating the decrease width of the water absorption wavelength light indicating the amount of raindrops, and in the end, this configuration cannot discriminate dirt. . Moreover, since two types of light having different wavelengths are projected on the one receiving side, two types of light are alternately projected, and the detection operation is synchronized with this light emitting operation. Therefore, there is a problem that the structure and control of the device are complicated. On the other hand, in an adhering matter detection device that uses the effect of collecting raindrops and the effect of blocking dirt, it is necessary to dispose a large number of light receiving elements in order to ensure sufficient detection accuracy, which is a disadvantage of high cost. was there.

The present invention has been devised in order to eliminate such disadvantages of the prior art, and its main purpose is to:
An object of the present invention is to provide a glass adhering matter detection device capable of accurately distinguishing raindrops and dirt with a simple configuration.

[0006]

According to the present invention, such an object is such that the light emitting means and the light receiving means are arranged so that the light from the light emitting means reaches the light receiving means after passing through the glass. A glass adhering matter detecting device for detecting an adhering state of raindrops or dirt on the glass surface based on a detection amount of light from the light emitting means in the light receiving means, wherein the light emitting means is water. The light receiving means averagely emits light in a wide wavelength band including an absorption wavelength, and the light receiving means mainly detects a light having a water absorption wavelength in a limited manner and a light emitted by the light emitting means. And a second light receiving element for detecting light having a non-water absorption wavelength within the wavelength band of 1.

In particular, the first light receiving element is a photodiode made of Ge, and the second light receiving element is GaA.
It is preferably a photodiode made of s.

[0008]

With this structure, the raindrop absorbs only the water absorption wavelength light detected by the first light receiving element, whereas the dirt is the light detected by both the first and second light receiving elements. Since both are blocked, it is possible to determine whether raindrops or stains are attached by comparing the changes in the detected amounts of the first and second light receiving elements. That is,
If the detection amounts of both the first and second light receiving elements are decreasing, it is determined that the glass is contaminated. On the other hand, when the detection amount of the first light receiving element is decreased while the detection amount of the second light receiving element is not decreased, it is determined that only raindrops are attached to the glass. In addition, it is possible to determine the amount of raindrops from the width of decrease in the detection amount of the first light receiving element.

In particular, a photodiode made of Ge having a detection sensitivity peak near the water absorption wavelength is used as the first light receiving element, and a photodiode made of GaAs having the detection sensitivity peak in a band different from the water absorption wavelength is used as the second light receiving element. If each is used, a simple configuration can be achieved while ensuring sufficient detection accuracy, and the manufacturing cost can be reduced.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be described in detail below with reference to specific embodiments shown in the accompanying drawings.

FIG. 1 shows a glass adhering matter detecting apparatus constructed according to the present invention. This adhering matter detection device is provided with a light emitting section 2 arranged on the upper surface of a hood 1 of an automobile.
And a control circuit 5 arranged at a proper place in the vehicle, which is arranged on the back side of the rearview mirror 3, and determines whether raindrops and dirt are attached to the outer surface of the windshield 6, and A wiper drive circuit 9 for operating the wiper motor 7 and the washer pump 8 according to the adhesion state.
It outputs an operation signal to.

The light emitting section 2 has a light emitting element 1 as a light emitting means.
No. 0, the light receiving section 4 has two built-in first and second light receiving elements 11 and 12 as light receiving means, respectively.
After the light of the light emitting element 10 projected toward the first side passes through the wiper wiping area of the windshield 6,
The second light receiving elements 11 and 12 are arranged so as to face each other.

The light emitting device 10 is, as shown in FIG.
Wide wavelength band including water absorption wavelength (0.5-2.0μ
m) is a light emitting diode made of SiC that emits light. On the other hand, the first light receiving element 11 has a detection sensitivity peak near the water absorption wavelength (0.6 to 1.8 μm).
And a second light receiving element 12
Is Ga that has a detection sensitivity peak in the wavelength band (0.6 to 0.9 μm) that is not absorbed by water and is blocked by dirt.
It is a photodiode made of As.

The light emitting element 10 and the first and second light receiving elements 11 and 12 are electrically connected to the control circuit 5, and the light emitting element 10 emits light by the electric power supplied from the control circuit 5. On the other hand, the output signals from the first and second light receiving elements 11 and 12 which detect this light are output to the control circuit 5.
Is input to The control circuit 5 causes the wiper drive circuit 9 to connect the wiper motor 7 and the washer pump 8 in accordance with the state of adhesion of raindrops and dirt determined based on this signal.
Is output.

An example of the control at this time will be described below with reference to the flow chart shown in FIG. When the wiper switch is turned on, first, in step S1, the state of attachment of raindrops and dirt is determined. The state of adhesion of raindrops and dirt is determined by comparing the detection values of the first and second light receiving elements 11 and 12 with predetermined reference values stored in advance in the control circuit 5. For example, the first
If the detection values of the second light receiving elements 11 and 12 are both below the reference value, it is determined that dirt is attached, and the process proceeds to step S2. In step S2, the operation signal of the washer pump 8 is output from the control circuit 5 to the drive circuit 9, the washer pump 8 is operated for a predetermined time, and the process proceeds to step 3. In step 3, the wiper operation signal is output from the control circuit 5 to the drive circuit 9, the wiper motor 7 is operated for a predetermined time, and the dirt is removed.

On the other hand, if only the detection value of the first light receiving element 11 is below the reference value in step S1, the non-water absorption wavelength light is not blocked, and only the raindrops are attached. It is determined and the process proceeds to step S4. In step S4, the amount of raindrops, that is, the intensity of the rainfall condition is determined by comparison with the rainfall determination value stored in advance in the control circuit 5. When it is determined that the amount of rainfall is large, the process proceeds to step S5, the control circuit 5 outputs a wiper continuous operation signal to the drive circuit 9, and the wiper motor 7 is continuously operated in step S6. On the other hand, if it is determined that the amount of rainfall is small in step S4, step S7
, The wiper intermittent operation signal is output, and step S8 is performed.
The wiper motor 7 is operated intermittently. At this time, the wiping speed is set in the continuous operation, and the intermittent time is set in the intermittent operation, depending on the intensity of rainfall, that is, the degree of difference between the detection value of the first light receiving element 11 and the rain amount determination value.

In the present embodiment, two types of photodiodes are used as the light receiving means, but the present invention is not limited to this. For example, it is possible to detect broadband light including water absorption wavelengths. The same two light receiving elements are used, one of the light receiving elements is provided with a filter glass that transmits the water absorption wavelength light in a limited manner to form a first light receiving element, and the other light receiving element receives the non-water absorption wavelength light. The second light receiving element may be provided by disposing a filter glass that allows limited transmission. Further, the light emitting diode as the light emitting means may be replaced with a tungsten lamp.

Further, in the present embodiment, the light emitting portion is provided on the bonnet and the light receiving portion is provided on the rearview mirror. However, for example, the light emitting portion may be provided on the wiper arm or the light receiving portion may be provided on the dashboard. May be. Further, a reflection mirror may be arranged with a glass in between so as to face the light emitting section and the light receiving section arranged in parallel. By doing so, since the light is transmitted through the glass twice, the fluctuation range of the detection amount due to the adhered matter is amplified,
The detection sensitivity is improved.

[0019]

As described above, according to the present invention, raindrops and dirt can be accurately discriminated with a simple structure.
The manufacturing cost can be reduced and the convenience and safety can be further improved by applying the invention to the automobile wiper device as in the above embodiment.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a situation in which a glass deposit detection device according to the present invention is applied to an automobile.

FIG. 2 is a graph showing the emission intensity of the light emitting element and the detection sensitivity of the first and second light receiving elements.

FIG. 3 is a flow chart showing control of a wiper and a washer of an automobile using the glass deposit detection device shown in FIG.

[Explanation of symbols]

 1 bonnet 2 light emitting part 3 rearview mirror 4 light receiving part 5 control circuit 6 front window glass 7 wiper motor 8 washer pump 9 wiper drive circuit 10 light emitting element 11 first light receiving element 12 second light receiving element

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigeki Aoki 1-2681 Hirosawa-cho Kiryu-shi Gunma Mitsuba Electric Mfg. Co., Ltd. (72) Inventor Takeshi Sekiguchi 1261 Hirosawa-cho Kiryu-shi Gunma Share Company Mitsuba Electric Works

Claims (2)

[Claims] 1. A light emitting means and a light receiving means are arranged such that light from the light emitting means reaches the light receiving means after passing through glass, and detection of light from the light emitting means in the light receiving means. A glass adhering matter detection device for detecting an adhering state of raindrops or dirt on the glass surface based on the amount, wherein the light emitting means emits light in a wide wavelength band including a water absorption wavelength on average. The light receiving means is mainly a first light receiving element that mainly detects light having a water absorption wavelength,
An adhering matter detecting device for glass, comprising a second light receiving element for limiting detection of light having a non-water absorption wavelength within a wavelength band of light emitted by the light emitting means. 2. The first light receiving element is a photodiode made of Ge, and the second light receiving element is GaAs.
The glass adhering matter detection device according to claim 1, which is a photodiode made of