JPS61284646A - Waterdrop detecting device for windshield - Google Patents

Abstract

PURPOSE:To drive automatically by providing light projecting means which irradiate the 1st light having large transmission loss to a windshield and the 2nd light having the opposite property from it. CONSTITUTION:A light emitting element 2 irradiates the light A having the large transmission loss to the windshield 3 by a driving circuit 12 and a light emitting element 4, on the other hand, irradiates the light B having the opposite property from it by a driving circuit 14. A detecting circuit 16 detects cases wherein waterdrops are present on the internal surface of the windshield 3 and the light A is detected, wherein waterdrops are present on only the external surface of the windshield 3 and the light A is detected, and wherein light from the headlamps of a rear following vehicle is glaring on the basis of the output signal of a photodetecting element 5 which photodetects the reflected light of the light beams A and B from waterdrops and the output signal of a photodetecting element 8 which photodetects the light from the headlamps of the rear following vehicle. Then, a defroster driving device 17, a wiper driving device 18, and a nonglaring mirror driving device 19 are driven on the basis of those detection signals when necessary.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention is a method for detecting water droplets attached to a windshield in order to automatically start a windshield wiper, defroster, etc. as required. Technology) When the windshield becomes cloudy due to water droplets adhering to the inner surface of the windshield while the vehicle is in motion, or when water droplets adhere to the outer surface of the windshield due to raindrops, fog, etc.
The vehicle's defroster, windshield wiper, etc. are activated to ensure visibility.

(Problem to be Solved by the Invention) Conventionally, the driver or the like has to look at the condition of the windshield to determine whether or not to start a device such as a defroster or windshield wiper, or whether to stop it or not. The starting or stopping of each device is performed manually based on such judgment.

However, when the vehicle is running, such operations are troublesome, and it is preferable to perform them automatically.For this reason, a device is used to determine whether to start or stop the defroster or windshield wiper, and based on the result of this determination. Based on this, it is hoped that the defroster, A11-\I↓^ノ+lpi-no, and S-terminal will also be seriously violated.

Therefore, the present invention was made in order to meet such a demand, and its purpose is a defroster.

It is an object of the present invention to provide a water droplet detection device for a window glass that can automatically determine whether to start or stop each device such as a windshield wiper, and thereby automatically drive each device.

(Means for Solving the Problems) In order to solve the above problems, the present invention is provided so as to face the windshield (3) of a vehicle, and the windshield (3)
); and a light projecting means for irradiating the first light A having a large transmission loss to the window glass (3) and the second light B having a small transmission loss to the window glass (3);
, the second lights A and H are reflected by the water droplets (8)..., (7)... adhering to the interior surface (3a) or the outer surface (3b) of the windshield (3). and detecting means for receiving the reflected light and detecting the reflected light of the first light A and the second light B.

(Function) The above means works as follows. For example, when the light projecting means and the detection means are provided inside the vehicle, the window glass (3)
When water droplets (8)... adhere to the interior side (3a) of the vehicle, the first and second lights A and B are diffusely reflected on the surface of the water droplets.

On the other hand, water droplets (7) on the outside of the window glass (3b)...
・If attached, the first light A, which has a large transmission loss to the windshield (3), is attenuated within the windshield (3), and only the second light B, which has a small transmission loss, passes through the windshield (3). Water droplet (7)... Diffusely reflected on the surface. Therefore, when the first light A is detected by the detection means (the second light B is also detected at the same time), the detection means detects the first light A (second light B is also detected at the same time).
), if only the second light B is detected, the outside of the vehicle (
It can be seen that water droplets are attached only to 3b).

Incidentally, if there are no water droplets attached to the window glass (3), neither of the reflected lights of the first and second lights A and H is detected.

(Embodiments) Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic diagram showing the sensor section of the water droplet detection device and the principle of detecting water droplets.

In the sensor part (1), the code (2) is the windshield (
3), the first light A has a property of large transmission loss.
The first light emitting element (4) that emits light is the second light emitting element that emits the second light B that has a property of having small transmission loss with respect to the windshield (3), and is the second light emitting element (5).・
・ is a light-receiving element that receives these lights and converts them into electrical signals.

Now, the sensor part (1) is installed in the vehicle interior near the windshield (3) with the light emitting elements (2), (4) and the light receiving element (5).
... are provided to face the window glass (3), and the first and second lights A and B are irradiated toward the window glass (3) from the respective light emitting elements (2) and (4).

At this time, as shown by ■, if there are no water droplets attached to both the interior and exterior surfaces of the windshield (3), a portion of the first light A is transmitted to the inner surface of the windshield (3).
The second light B is reflected in a predetermined direction by the inner surface (3a) of the windshield (3), and the rest is absorbed in the windshield. At the same time, the remaining light passes through the window glass (3) and travels, and these lights are not detected by the light receiving element (5).

Next, when water droplets (8)... adhere to the inner surface of the windshield (3) as shown by ■, the first. Second light A, B
are diffusely reflected by the water droplets (6), and a portion of them is detected by the light receiving elements (5).

The outer surface of the windshield (3) (
If the water droplets (7) ... adhere only to 3b), in this case, a part of the first light A is reflected by the inner surface (3a) of the windshield (3), as in the case of the windshield. The rest is absorbed into the windshield. On the other hand, the second light B is the light that has passed through the window glass (3) and the water droplets (7).
It is diffusely reflected by..., and a part of it is reflected by the light receiving element (5)...
・Detected by.

Therefore, when the first light A is detected by the light receiving element (5) (in this case, the second light B is also detected), the inner surface of the windshield (3) (on the inside of the vehicle) If only the second light B is detected, it is detected that water droplets are attached only to the outer surface (outside the vehicle interior) of the windshield (3).

In addition, in the sensor part (1), the reference numeral (8) is a light receiving element provided on the opposite side from the light emitting elements (2), (4) and the light receiving element (5). It is used to detect headlight light from cars.

Figures 2 and 3 are diagrams showing examples of how the sensor unit is mounted. 1st as shown. The second light-emitting elements (2), (4) and the light-receiving element (5) for detecting reflected light are arranged to face the front windshield (3), while the headlights of the rear vehicle are arranged to face the front windshield (3). The light-receiving element (8) that detects light is mounted toward the rear of the vehicle.

FIG. 4 is a block diagram showing the configuration of this device. The first light A, which has a large transmission loss with respect to the window glass (3), has the property of being absorbed within the glass. For example, if the glass has the property of infrared absorption, the infrared light has the property of absorbing ultraviolet light. If it has, ultraviolet light is used, whereas for the second light B, light having properties opposite to those described above is used. In FIG. 4, reference numeral (12) is a drive circuit for the first light emitting element (2), and the first light emitting element (2) is connected to this drive circuit (
12), the light A that has been amplitude modulated to 500H2 is transmitted through the beam lens (13) to the front windshield (3).
). On the other hand, reference numeral (14) is a drive circuit for the second light-emitting element (4), and this light-emitting element (4) transmits the light B, which has been amplitude-modulated to 1 KHz by the drive circuit (10), through a beam lens (15). ).

The code (18) is the first. Based on the output signals from the light receiving element (5) that receives the second lights A and H reflected by water droplets, and the light receiving element (8) that receives the headlight light of the rear vehicle, This is a detection circuit that detects the reflected light of the second lights A and H and the headlight light. That is, this detection circuit (IB) detects when water droplets adhere to the inner surface of the window glass (3) (when the first light A is detected).
When water droplets adhere only to the outer surface of the windshield (3) (when only the second light is detected), when the headlights of the rear vehicle are dazzling, etc. are detected, and the defroster is activated based on the detection signal. The device (17), the wiper drive device (1 day), and the anti-glare mirror drive device (19) are driven as necessary. Incidentally, there may be cases where water droplets adhere to both sides of the window glass at the same time, but in this case, the defroster (17) is first driven by detecting the first light A and removes the water droplets from the inner surface of the glass. Then, by detecting only the second light B, the wiper (18) is driven to remove the water droplets.

The light-receiving element (5) can also detect light outside the first and second scenes described above, for example, by detecting street lights and tunnel lights, small lights, headlights, etc. It is also possible to drive the switch driving device (20).

Figure 5 is a configuration diagram of this detection circuit, in which the light receiving element (5)
. . , and the light detected in (8) is converted into an electrical signal, and then separated into a DC component and an AC component by a filter (22) via an amplifier (21).
3), through the AC amplifier (24), the DC component is 1'+-
On the other hand, the AC component is detected by the frequency discrimination circuit (2B) as the first light A (500Hz signal detection), Second
Detection of light B (1 KHz signal detection), and detection of illumination light from road lights and tunnel lights (0 to 1oO
Hz signal detection) is performed.

In this way, according to this embodiment, there is one light emitting element (2).

(4)- and these drive circuits (12) and (14) constitute a light projecting means, while the light receiving element (5) and the detection circuit (1
6) constitutes a detection means for detecting reflected light, and is capable of detecting water droplets attached to the inner and outer surfaces of the front windshield, as well as detecting ambient light and headlights of a vehicle behind, and detecting these as necessary. It is possible to drive each device to cope with the situation, and the troublesome operation can be reduced.

Note that the present invention is not limited to the embodiments, and for example, the number of light-receiving elements (5) need not be limited to three, but may be one as shown in FIG. As the element, a photodiode, phototransistor, CdS, etc. can be used, while as the light emitting element, a light emitting diode, a laser diode, etc. can be used. Further, in this embodiment, the detection of water droplets on a front windshield is taken as an example, but the present invention may also be used on a rear windshield, a side windshield, etc.

(Effects of the Invention) As is clear from the above description, according to the present invention, by detecting water droplets attached to the window glass, the defroster
It is possible to provide a water droplet detection device for a windshield that can automatically determine whether to start or stop each device such as a windshield wiper, and thereby can automatically drive each device.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram showing the sensor section of the water droplet detection device and the principle of detecting water droplets, Figures 2 and 3 are diagrams showing examples of implementation of the sensor section, and Figure 4 is a block diagram showing the configuration of this device. 5 is a block diagram of the detection circuit, and FIG. 6 is a diagram showing the separate male side. In the drawings (2)...first light emitting element (3)...window glass (4)...second light emitting element (5)... - Light receiving element (12)...Drive circuit (14)...Drive circuit (16)...Detection circuit A...First light B... ...It is the second light.

Claims (1)

[Scope of Claims] Light projecting means that is provided to face a windshield of a vehicle and irradiates first light that has a large transmission loss to the windshield and second light that has a small transmission loss to the windshield; Of the first and second lights irradiated by the light means, reflected light reflected by water droplets attached to the interior surface or outer surface of the window glass is received, and the first light and the second light are A water droplet detection device for a window glass, comprising a detection means for detecting reflected light.