JPH0519935B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a window glass water drop detection device for detecting water droplets adhering to a window glass in order to automatically start a windshield wiper, defroster, etc. as necessary. (Prior art) When the windshield becomes foggy due to water droplets adhering to the inner surface of the windshield while the vehicle is running, raindrops,
When water droplets adhere to the outer surface of the windshield due to fog or the like, visibility is maintained by driving the defroster, windshield wiper, etc. installed on the vehicle. (Problems to be Solved by the Invention) Conventionally, it has been difficult to determine whether or not to start a device such as a defroster or a windshield wiper.
Alternatively, the driver or the like determines whether or not to stop the vehicle by looking at the state of the window glass, and the starting or stopping of each device is performed manually based on such a determination. However, when the vehicle is running, such operations are troublesome and are preferably performed automatically. Therefore, it is desired that a device determine whether to start or stop the defroster, window wiper, etc., and automatically drive the defroster, window wiper, etc. based on the result of this determination. The present invention was developed in response to such a need, and its purpose is to automatically determine whether to start or stop each device such as a defroster or windshield wiper. An object of the present invention is to provide a water droplet detection device for a window glass that can automatically drive the device. (Means for Solving the Problems) In order to solve the above problems, the present invention provides a first light A that is provided to face the windshield 3 of a vehicle and that has a large transmission loss with respect to the windshield 3. The second one with smaller transmission loss for
of the first and second lights A and B emitted by the light projecting means,
The reflected light reflected by the water droplets 6..., 7... adhering to the interior surface 3a or the outer surface 3b of the window glass 3 is received, and the first light A and the second light are
and detection means for detecting the reflected light of the 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, when water droplets 6 adhere to the interior side 3a of the window glass 3, the first and second lights A and B are diffusely reflected on the surface of the water droplets. be done. On the other hand, when water droplets 7... adhere to the outside 3b of the window glass, the first light A with a large transmission loss to the window glass 3 is attenuated within the window glass 3, and only the second light B with a small transmission loss passes through the window. Water droplets 7 pass through the glass 3 and are diffusely reflected on the surface. Therefore, the detection means detects the first light A
If the second light B is detected (the second light B is also detected at the same time), water droplets are attached to the inside of the vehicle interior 3a, and if only the second light B is detected, water droplets are attached only to the outside of the vehicle interior 3b. I understand that. Note that 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 B 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 section 1, the code 2 indicates the window glass 3.
In contrast, a first light emitting element 4 emits a first light A having a property of having a large transmission loss, and reference numeral 4 is a first light emitting element which emits a second light B having a property of having a small transmission loss. 2 is a light emitting element, and numerals 5... are light receiving elements that receive these lights and convert them into electrical signals. Now, such a sensor unit 1 is installed in the vehicle interior near the windshield 3, with light emitting elements 2, 4 and light receiving elements 5 facing the windshield 3, and each light emitting element 2,
4, the first and second lights A and B are sent to the window glass 3.
irradiate towards. As shown in this case, when there are no water droplets attached to both the interior and exterior surfaces of the window glass 3, a portion of the first light A is reflected in a predetermined direction by the inner surface 3a of the window glass 3. while the rest is absorbed within the window glass, and similarly, a part of the second light B is reflected in a predetermined direction by the inner surface 3a of the window glass 3, and the rest passes through the window glass 3 and proceeds. These lights are not detected by the light receiving elements 5. When water droplets 6... adhere to the inner surface of the window glass 3 as shown below, the first and second lights A,
B is diffusely reflected by the water droplets 6, and a portion of it is detected by the light receiving elements 5. When water droplets 7 adhere only to the outer surface 3b of the window glass 3 as shown in , in this case, part of the first light A is reflected by the inner surface 3a of the window glass 3, as in the case of . , the rest is absorbed into the windshield. On the other hand, the second light B is transmitted through the window glass 3 and is diffusely reflected by the water droplets 7 .
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)
On the inner surface of the windshield 3 (inside the vehicle interior),
When only the second light B is detected, it is detected that water droplets are attached only to the outer surface of the window glass 3 (outside the vehicle interior). In the sensor section 1, reference numeral 8 denotes a light receiving element provided on the opposite side from the light emitting elements 2, 4 and the light receiving element 5, and is used to detect headlight light from a car behind the vehicle. be. FIG. 2 and FIG. 3 are diagrams showing an example of mounting the sensor section, and the sensor section 1 is mounted on the support arm section 11 of the rearview mirror 10 provided at the front upper part of the driver's seat. 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 light-receiving element 8 for detecting the headlight light of the rear vehicle is placed at the rear of the vehicle, as shown in FIG. It is mounted towards the target. FIG. 4 is a block diagram showing the configuration of this device. The first light A having a large transmission loss with respect to the window glass 3 has a property of being absorbed within the glass,
For example, if the glass has the property of infrared absorption, infrared light is used, and if the glass has the property of ultraviolet absorption, ultraviolet light is used, whereas the second light B has the property opposite to the above. light 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 driven by this drive circuit 12.
Beam lens 1 transmits light A that has been amplitude modulated at 500Hz.
3 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 is connected to this drive circuit 1.
4, the light B whose amplitude has been modulated to 1 KHz is irradiated through the beam lens 15. Reference numeral 16 indicates the first and second lights based on the output signals from the light receiving element 5 which receives the reflected light of the first and second lights A and B by the water droplets, and the light receiving element 8 which receives the headlight light of the vehicle behind. This is a detection circuit that detects the reflected lights of the second lights A and B and the headlight light. That is, this detection circuit 16 detects when water droplets adhere to the inner surface of the window glass 3 (first light A
is detected), when water droplets are attached only to the outer surface of the windshield 3 (when only the second light is detected), and when the headlights of the vehicle behind are dazzling, etc., and the detection signal is Based on this, the defroster drive device 17, wiper drive device 18, and anti-glare mirror drive device 19 are respectively 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 activated by first detecting the first light A.
is driven to remove water droplets from the inner surface of the glass, and then the wiper 18 is driven by detection of only the second light B to remove the water droplets. The light-receiving elements 5 can also detect light other than the first and second lights described above, and for example, by detecting street lights or tunnel lights, the light receiving elements 5 can detect light such as the switch driving device 20 of a small light or a headlight. It can also be driven. FIG. 5 is a configuration diagram of this detection circuit, in which the light detected by the light receiving elements 5 and 8 is converted into an electric signal, and then separated into a DC component and an AC component by a filter 22 via an amplifier 21. , respectively, the DC component is detected by the comparator 25 as the headlight light of the vehicle behind, while the AC component is detected by the frequency discrimination circuit 26 as the first light A (500Hz signal detection). , second light B
detection (1KHz signal detection), and detection of illumination light from road lights and tunnel lights (0 to 100Hz signal detection).
signal detection) is performed. As described above, according to this embodiment, the light emitting elements 2 and 4
The drive circuits 12 and 14 constitute a light projecting means, while the light receiving element 5 and the detection circuit 16 constitute a detection means for detecting reflected light, and detect water droplets attached to the inner and outer surfaces of the front windshield. At the same time, it is also possible to detect ambient light and the headlights of the vehicle behind, and to drive each device to deal with these as necessary, reducing the complexity of operation. Note that the present invention is not limited to the examples,
For example, the number of light receiving elements 5 need not be limited to three, and may be one as shown in FIG. A photodiode, phototransistor, CdS, etc. can be used as the light-receiving element, while a light-emitting diode, a laser diode, etc. can be used as the light-receiving element. 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 window glass, a side window glass, etc. (Effects of the Invention) As is clear from the above explanation, according to the present invention, by detecting water droplets attached to the window glass, it is possible to automatically determine whether to start or stop each device such as a defroster or a windshield wiper. Accordingly, it is possible to provide a water droplet detection device for a window glass in which each device can be automatically driven.

[Detailed description of the invention]

Fig. 1 is a schematic diagram showing the sensor section of the water droplet detection device and the principle of detecting water droplets, Figs. 2 and 3 are diagrams showing an example of the implementation of the sensor section, and Fig. 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 another embodiment. In the drawing, 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] 1. Light projecting means that is provided to face the windshield of a vehicle and irradiates a first light with a large transmission loss to the windshield and a second light with a small transmission loss to the windshield; The first and second lights irradiated by the light projecting means
detection means for receiving reflected light reflected by water droplets attached to the interior surface or outer surface of the window glass, and detecting the reflected light of the first light and the second light. Water drop detection device for window glass.