JPH0267945A - Water-droplet detecting apparatus for window glass - Google Patents

Abstract

PURPOSE:To detect the presence or absence of water droplets positively by judging whether the droplets are attached on the inner and outer sides of a window glass or not based on the output levels of the output signal from a detecting means before and after the operation of a wiper. CONSTITUTION:A sensor part 3 is arranged so that it is positioned in the wiping region of a wiper which wipes the outer surface of a window glass at the inside of the window glass of a vehicle. The sensor part is arranged at the position separated from the glass so as to face the glass. The sensor part 3 comprises a light projecting means 4 which projects light toward the window glass and a detecting means 5 which detects the light reflected from the window glass. The signal outputted from a photodetector 8 is inputted into a control unit 11 through an amplifier circuit 9 and a filter 10. In the control unit 11, whether water droplets are attached on the inner and outer surfaces of the window glass or not is judged.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a windshield that detects water droplets adhering to the inner and outer surfaces of the windshield in order to automatically turn on and off windshield wipers, defrosters, etc. depending on the situation. This invention relates to a water droplet detection device.

(Prior Art) Conventionally, a windshield water droplet detection device is known which includes a light projecting means for irradiating light toward a windshield of a vehicle, and a detection means for detecting light reflected from the windshield. For example, JP-A-61-284845 and JP-A-61-284646).

In this conventional windshield water drop detection device, the light emitting means is composed of two light emitting elements, and when the light from one light emitting element is detected (the light from the other light emitting element is also detected at the same time). , it can be seen that water droplets are attached to the inner surface of the window glass, and if only the light from the other light emitting element is detected, it can be seen that water droplets are attached only to the outer surface of the window glass. It has become.

(Problems to be Solved by the Invention) In the conventional windshield water droplet detection device, the light emitting means emit different lights. The device consists of 1 light emitting elements, and the presence or absence of water droplets on the inner and outer surfaces of the window glass is determined based on which light is detected, which results in a complicated configuration and increased cost. was there.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a water droplet detection device for a windshield that has a simple configuration and can smoothly reduce costs.

(Means for Solving the Problems) In order to achieve the above object, a water droplet detection device for a windshield according to the present invention includes a light projecting means and a detection means that are spaced apart from each other on the inside of the windshield and are arranged on the outside surface of the windshield. is located within the wiping area of a wiper for wiping away water, and detects water droplets on the inner and outer surfaces of the windshield based on the output level of the output signal from the detection means before and after the wiper is operated as described in 11j. This feature is characterized by determining whether or not the system is in a stalemate.

(Function) After the wiper is operated, if the level of the output signal from the detection means is within a predetermined range of levels free of water droplets, it is determined that water droplets are attached only to the outer surface of the window glass. Furthermore, if the level of the output signal from the detection means exceeds a predetermined range of levels free of water droplets after the wiper is operated, it is determined that water droplets have also adhered to the inner surface of the window glass.

(Example) Hereinafter, one example of the present invention will be described based on the drawings. 1st
The figure is a partially omitted front view of the vehicle showing the installation position of the sensor section of the water droplet detection device of the present invention, and Figure 2 is an enlarged view of the internal part of Figure 1. In the window glass
A sensor unit 3 is disposed inside thereof, facing away from it and located within the wiping area (the area surrounded by the dashed line in Fig. 1) of the wiper 2 that wipes the outer surface of the windshield l. has been done. This sensor section 3, as shown in FIG.
a light projecting means 4 that irradiates light toward the window glass l;
Detection means 5 for detecting light reflected from the window glass l
It consists of The light projecting means 4 consists of a drive circuit 6 and a light emitting element 7, and the light emitting element 7 emits light (for example, non-visible light such as infrared light) that has been amplitude-modulated to a predetermined frequency by the drive circuit 6 to a window glass. Irradiate towards l. Further, the detection means 5 includes a light receiving element 8, an amplifier circuit 9, a filter 10, and a control unit 11. The light receiving element 8 receives the light reflected from the window glass l and converts it into an electrical signal. The output level of the signal output from the light receiving element 8 changes depending on the amount of water droplets adhering to the inner or outer side of the window glass l.

The signal output from the light receiving element 8 is amplified by the amplifier circuit 9 and then input to the filter IO.

This filter IO extracts only a specific frequency corresponding to the frequency of light from the light emitting element 7.

The control unit 11 determines whether water droplets are attached to the inner or outer surface of the window glass l based on the signal input from the filter 10, and based on the determination result,
A drive signal is output to the wiper drive device 12 or the defroster drive device 13 to drive the wiper 2 or the defroster (not shown).

As shown in FIG. 2, the sensor section 3 is mounted on a support arm section 14a of a room mirror 14 provided at the front upper part of the driver's seat, with a light emitting element 7 and a light receiving element 8 facing the windshield l.

Next, the operation of the windshield water droplet detection device of the present invention having the above structure will be explained with reference to FIGS. 4 to 7. Light is emitted from the light emitting element 7 toward the window glass 1.

At this time, as shown in FIG. 4(a), the window glass 1
If there are no water droplets on either the inner or outer surface of the
A part of the light is reflected by the inside and inner surface of the window glass 1, and the rest passes through the window glass 1 and proceeds. A portion of the reflected light from the window glass l is detected by the light receiving element 8, and a signal at a predetermined output level is output from the light receiving element 8. The output level at this time is within the range of L1 in FIGS. 5 to 7 and hardly changes.

Further, as shown in FIG. 4(b), when water droplets 15 adhere to the inner surface of the window glass l, the light is diffusely reflected by the water droplets 15, a part of which is detected by the light receiving element 8, and the light is detected by the light receiving element 8. 8, a signal with an output level proportional to the amount of attached water droplets 15 is output.

Furthermore, as shown in FIG. 4(c), the window glass 1
When water droplets 16 adhere only to the outer surface of the window, the light passes through the windshield l and is diffusely reflected by the water droplets 16, a part of which is detected by the light-receiving element 8, and the light-receiving element 8 detects the amount of water droplets 16 attached. A signal with an output level proportional to is output.

In this way, the signal output from the light receiving element 8 is input to the control unit 11 via the amplifier circuit 9 and the filter 10, and in this control unit 11, the window It is determined whether water droplets are attached to the inner or outer surface of the glass l. That is, the output level of the signal output from the light receiving element 8 is
If it is within the range L1 in the figure, it is determined that there are no water droplets attached to either the inner or outer surface of the windshield 1, and the wiper 2 and defroster do not operate. Further, when the output level of the signal exceeds the range Ll and exceeds the range L2, which is a range larger than this Ll, it is determined that a predetermined amount or more of water droplets 16 are attached to the windshield l, and the wiper is activated. A drive signal is output to the device 1111, and the wiper 2 is activated (point a in FIG. 5). Note that due to the operation of the wiper 2, the output level of the signal output from the light receiving element 8 changes significantly (points 0 and 0 in FIG. 5).

If the output level of the output signal from the light-receiving element 8 after the wiper 2 is activated returns to within the output level L1 range at which no water droplets adhere to the windshield 1, water droplets will appear on the inner surface of the windshield l. It is determined that there is no adhesion, and the defroster does not operate (point d in Figure 5).

Further, as shown in FIG. 6, the output level h of the output signal from the light receiving element 8 after the wiper 2 is activated is lower than the output level g before the wiper 2 is activated, but the output level L+ is lower than the output level g before the wiper 2 is activated. If it exceeds the range, it is determined that water droplets 15 are also attached to the inner surface of the window glass l, and a drive signal is output to the defroster drive device 12 to operate the defroster.

Furthermore, as shown in FIG. 7, if the output level from the light receiving element 8 after the wiper 2 is activated is not different from the output level before the wiper 2 is activated, that is, if the output level gradually increases, the windshield l It is determined that water droplets are attached only to the inside of the defroster, and a drive signal is output to the defroster drive device 12 to operate the defroster and the roaster (first point in FIG. 7).

(Effects of the Invention) As described above, the windshield water droplet detection device of the present invention has the following features:
The light projecting means and the detecting means are disposed on the inside of the windshield and are spaced apart from each other and located within the wiping area of a wiper that wipes off the outer surface of the windshield, and the light emitting means and the detection means are disposed in a wiping area of a wiper that wipes the outside surface of the windshield, and Based on the output level of the output signal from the detection means, there are 11 water droplets on the inner and outer surfaces of the window glass.
This feature is characterized by determining whether or not the vehicle is being worn.

Therefore, not only can the presence or absence of water droplets be detected reliably, but the configuration is simple and costs can be smoothly reduced.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a partially omitted front view of a vehicle showing the installation position of the sensor section of the water droplet detection device of the present invention, and FIG. 3 is a circuit configuration diagram of the sensor section, FIG. 4 is a schematic diagram showing the principle of detecting water droplets in the sensor section, and FIGS. 5 to 7 are the output Norbel lines of the signal output from the light receiving element. It is a diagram. l... Windshield, 2... Wiper, 4... Light emitting means, 5... Detecting means, 7... Light emitting element, 8...
・Photodetector, 15.16...Water drop.

Claims (1)

[Claims] 1. A windshield water drop detection device comprising a light projecting means for emitting light toward the windshield of a vehicle, and a detecting means for detecting light reflected from the windshield, wherein the light projecting means and the detecting means are arranged to be spaced apart from each other on the inside of the window glass and located within the wiping area of a wiper that wipes the outside surface of the window glass, and output signals from the detection means before and after the wiper is operated. A water droplet detection device for a window glass, characterized in that it determines whether water droplets are attached to the inner or outer surface of the window glass based on the output level of the window glass.