JPH05264496A - Raindrop sensor - Google Patents

Abstract

PURPOSE:To prevent erroneous detection of a raindrop sensor which is formed by providing a pair of transparent electrodes within a wiper blade wiping area of a wind shield. CONSTITUTION:A raindrop sensor 1 is laid out within a wiper blade wiping area 4 of a wind shield 2 in a glass structure which is formed where a glass 5 outside car and a glass 6 inside car are laminated each other while they sandwich an intermediate film 7. The raindrop sensor 1 consists of raindrop detection parts 8a and 8b which consist of double comb-shaped patterns which are combined alternately, leading wire parts 9a and 9b reaching the terminal edge of the wind shield 2, and terminal parts 10a and 10b. A transparent conductive film 11 is coated on the surface which contacts the intermediate film 7 of the glass 6 outside car as a third transparent electrode. Influences due to a wire blade 3 for electrostatic capacity of both leading wire parts 9a and 9b and raindrops outside the wire blade wiping area 4 can be prevented, thus resulting in no erroneous detection.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a raindrop sensor used in an automatically controllable wiper device of an automobile, and more particularly to a raindrop sensor having a pair of transparent electrodes arranged in a wiper wiping area of a windshield.

[0002]

2. Description of the Related Art Conventionally, an automobile has an automatic wiper device which detects raindrops when it rains and automatically operates the wiper device. There are various raindrop sensors used in this auto wiper device, for example, Japanese Patent Laid-Open No. 61-76.
As disclosed in Japanese Patent Publication No. 946, there is a method in which rainfall is judged by detecting a change in capacitance between both electrodes due to a water droplet attached between the pair of electrodes.

The sensor having the above structure is arranged in the wiper wiping area of the windshield. In that case,
It is desirable that both electrodes are transparent electrodes, and by doing so, the visibility is not obstructed by both electrodes. Further, since the both electrodes are embedded in the windshield, it is necessary to bring the terminals for both electrodes out of the windshield and electrically connect them to the control unit.

By the way, when the lead wire connecting the detection portion of the electrode and the terminal is drawn across the stop position of the wiper blade, it is affected by the wiper blade at the stop position and the lead wire between the two electrodes is affected. There is a possibility that the capacitance may change and false detection may occur. Even if the lead wires of both electrodes are pulled out while avoiding the wiper blade stop position, it is unavoidable that they cross the outside of the wiper wiping area. There is a risk of detection.

[0005]

SUMMARY OF THE INVENTION In view of the problems of the prior art as described above, a main object of the present invention is to provide a raindrop sensor in which a pair of transparent electrodes are arranged in a wiper wiping area of a windshield. Another object of the present invention is to provide an improved raindrop sensor for preventing the false detection.

[0006]

According to the present invention, such an object exists in a windshield composed of a glass on the inside of a vehicle and a glass on the outside of the vehicle which are bonded to each other with an interlayer film interposed therebetween. Is a raindrop sensor for performing wiper control by detecting raindrops due to a change in capacitance between a pair of transparent electrodes provided in a wiper wiping area at a distance from each other. A third transparent provided between the inner glass and the intermediate film, and electrically shields the lead line portion of the both transparent electrodes outside the wiper wiping area between the intermediate film and the vehicle exterior glass. This is achieved by providing a raindrop sensor characterized in that electrodes are provided.

[0007]

By doing so, it is possible to detect the change in the electrostatic capacitance between the pair of transparent electrodes due to the water droplets attached to the windshield, and to judge the rainfall, and at the same time, to determine whether or not the area outside the wiper wiping area of both electrodes Since both lead wire portions are electrically shielded by the third transparent electrode, even when the lead wire portion of the windshield crosses the stop position of the wiper blade or crosses the outside of the wiper wiping area, it is not affected by the wiper blade or water droplets. It is possible to prevent electrical influence on both lead wire portions.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic perspective view showing a raindrop sensor to which the present invention is applied. As shown in the figure, the raindrop sensor 1 is provided on a front windshield 2 of an automobile. A wiper wiping area 4 to be wiped by the wiper blade 3 of the wiper device is defined on the surface of the windshield 2, and the raindrop sensor 1 is arranged in the wiper wiping area 4.

Further, the windshield 2 includes a vehicle exterior glass 5 and a vehicle interior glass 6 as shown in the figure, and an intermediate film 7.
It is a laminated glass structure that is adhered to each other by heating and pressing with sandwiching. The intermediate film 7 is a transparent insulating film such as polyvinyl butyral.

The raindrop sensor 1 is composed of a pair of thin transparent electrodes made of, for example, an ITO (indium tin oxide) film used for a liquid crystal display and having a thickness of about 0.3 μm. The contact surface is coated by vacuum evaporation, sputtering or printing. Further, the raindrop sensor 1 extends from the raindrop detection portions 8 a and 8 b and the raindrop detection portions 8 a and 8 b, which are both comb-shaped patterns in which the transparent electrodes are alternately combined, and reaches the edge of the windshield 2. Lead line parts 9a and 9b
And terminal portions 10a and 10b exposed from the edge of the windshield 2. The raindrop detection unit 8a
The two comb-shaped patterns 8b are arranged at regular intervals.

Further, as shown in FIG. 2 which is an exploded perspective view, a third surface is provided on the surface of the exterior glass 6 in contact with the intermediate film 7.
The transparent conductive film 11 is coated and provided as the transparent electrode in the same manner as above. The conductive film 11 is formed so as to cover the outside glass 6 side portions of the lead wire portions 9a and 9b of the raindrop sensor 1 when viewed from the outside of the vehicle.

When the windshield 2 is assembled to the vehicle body, the terminal portions 10a and 10b and the terminal portion 11a of the conductive film 11 are bent along the vehicle interior glass 6. The free ends of the terminals 10a, 10b, and 11a are projected to the inside of the vehicle compartment and connected to the signal processing circuit 12 of the control unit. Signal processing circuit 1
2 is electrically connected to a wiper automatic control circuit 13, and the wiper automatic control circuit 13 is electrically connected to a wiper motor 14.

The signal processing circuit 12 includes, for example, each terminal portion 10
It has a resonance circuit connected to a and 10b. For example, by grounding one terminal portion 10a and operating the resonance circuit according to the output level of the other terminal portion 10b, raindrops adhere to the windshield 2 surface. When the capacitance between the raindrop detectors 8a and 8b of the raindrop sensor 1 changes, the change is detected and a rain signal is output to the wiper automatic control circuit 13. Then, the wiper motor 14 is appropriately automatically driven according to the drive signal from the wiper automatic control circuit 13.

The terminal portion 11a of the conductive film 11 is grounded by the signal processing circuit 12 so that the potential of the conductive film 11 becomes the ground level.

By the way, the raindrop sensor 1 thus constructed
As described above, since the change in the capacitance between the raindrop detection units 8a and 8b is detected to judge the rainfall, the drawers electrically connected to the raindrop detection units 8a and 8b are connected. If the capacitance changes between the line portions 9a and 9b, it may be erroneously detected as raindrop attachment depending on the level. That is, as shown in FIG. 1, when both lead line portions 9a and 9b cross the wiper blade 3 at the stop position, the wiper blade 3 and the wiper wiping area 4 of the windshield 2 can be used. It will cross the outside, but in that case, due to the raindrops remaining outside the wiper wiping area 4, both lead wire portions 9a and 9a
A change in capacitance occurs between b.

However, as described above, since the outside glass 5 side of both the lead wire portions 9a and 9b is covered with the conductive film 11, and the potential of the conductive film 11 is set to the ground level, Both lead wire portions 9a and 9b are
The conductive film 11 electrically shields the outside of the vehicle.
Therefore, it is possible to prevent the influence of the water droplets outside the wiper blade 3 and the wiper wiping area 4 on the electrostatic capacitance between the two lead wire portions 9a and 9b, so that erroneous detection due to them does not occur.

[0018]

As described above, according to the present invention, the raindrops adhering to the inside of the wiper wiping area are detected by the pair of transparent electrodes, and the lead line portion which crosses the outside of the wiper wiping area of these transparent electrodes is provided with the third transparent electrode. Since the electrodes are electrically shielded, it is possible to prevent the wiper blade in a stopped state and the influence of raindrops attached to the outside of the wiper wiping area on the electrostatic capacitance between the lead wire portions. Therefore, erroneous detection due to a change in capacitance between the two lead wire portions does not occur, and suitable automatic control can be performed by raindrop detection of the wiper device.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing a raindrop sensor provided on a windshield of an automobile to which the present invention is applied.

FIG. 2 is an exploded perspective view of a windshield to which the present invention has been applied.

[Explanation of symbols]

 1 Raindrop sensor 2 Windshield 3 Wiper blade 4 Wiper wiping area 5 Exterior glass 6 Interior glass 7 Intermediate film 8a / 8b Raindrop detection part 9a / 9b Lead wire part 10a / 10b Terminal part 11 Conductive film 11a Terminal part 12 Signal processing Circuit 13 Wiper automatic control circuit 14 Wiper motor

Claims (1)

[Claims] 1. A windshield consisting of a glass on the inside of a vehicle and a glass on the outside of the vehicle, which are attached to each other with an intermediate film sandwiched between them. A raindrop sensor for performing wiper control by detecting raindrops due to a change in electrostatic capacitance between transparent electrodes, wherein both transparent electrodes are provided between the vehicle interior glass and the intermediate film, and the intermediate film is provided. Between the vehicle exterior glass and
A raindrop sensor, characterized in that a third transparent electrode is provided to electrically shield the lead line portions of the both transparent electrodes outside the wiper wiping area.