JPH0894524A - Glass fog detector for automobiles - Google Patents

Abstract

(57) [Summary] [Object] The present invention is to automatically detect the presence or absence of fog on an automobile glass. [Configuration] The light emitter, the light receiver, the light emitter control device, and the light reception signal converter.

Description

Detailed Description of the Invention

The present invention is to automatically detect a fog generated on an automobile glass (5) by a light emitter (1), a light receiver (2), a light emitter control device (3), and a light receiving signal converter (4). .
Under various circumstances, automobile glass is cloudy due to the fog caused by minute water droplets on its interior surface. To remove this, a heat ray or an air conditioner is used, but in the past, there was no mechanism for automatically determining cloudy weather. For this reason, the driver had to judge that "the glass was cloudy" and manually operate the heat ray or the air conditioner. Performing these operations while driving is very dangerous.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is for automatically detecting the presence or absence of fog on the interior surface of an automobile glass, and it is possible to construct a system for automatically removing fog by combining it with a heat ray or an air conditioner. Becomes Of course, it is also possible to automatically turn off the cloud removal device after the cloud has been removed.

[Principle] (Refer to FIG. 2) FIG. 2 shows a cloudless glass (5), a light emitter (1), and a light receiver (2). The light from the light emitting device is reflected by the glass surface and travels toward the light receiving device at a constant rate. FIG. 3 shows a clouded glass. Small water droplets that cause cloudy weather (6)
Because the light from the light emitter is diffusely reflected or scattered,
The light reaching the light receiver (2) is reduced as compared with the case where there is no haze. Therefore, the light reception signal converter (4) may determine the intensity of light entering the light receiver (2). FIG. 4 shows the case where this principle is applied to the transmitted light of glass. Note that measures for malfunctions due to external factors will be described later.

[Details of each component]

(1) Light-emitting device: Any substance that emits light (2) Light-receiving device: Any substance that can convert an optical signal into an electric signal (3) Light-emitting device control device: Simply a power source for the light-emitting device Then
In the case of modulated light emission, a circuit for that purpose is also included. (4) Light receiving signal converter: An electronic circuit for judging the presence or absence of fog on automobile glass based on an electric signal from the light receiving device.

[Practice for Practical Use] In order to put the present invention into practical use, it is necessary to judge and cancel external light, that is, light from other than the light emitter. For that purpose, the following techniques can be applied.

[1: Use multiple light receivers] Use multiple light receivers and divide them into a group that detects only external light and a group that receives both external light and light from the light emitter. , Only the light from the light emitter can be detected.

[2: Modulated light emission] The light from the light emitter is modulated, and only its component is extracted from the signal from the light receiver. For example, the light emitter is caused to emit light at a specific frequency, and the signal from the light receiver is filtered to extract only that frequency component.

[3: Utilizing the directivity of light] Use highly directional objects for the light emitter and the light receiver so that light from another direction is not detected.

Application to Others The present invention has been devised for the purpose of detecting fog on the front, side, and rear glass surfaces of automobiles, but it can also be applied to the detection of raindrops or dirt on those outer surfaces and rearview mirrors.

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] January 10, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a plan view of the present invention. It consists of a light emitter and its control device, a light receiver and its signal conversion circuit. The light emitter and the light receiver are fixed to the automobile glass.

FIG. 2 is a plan view showing a cloudless glass, a light emitter, and a light receiver. The light from the light emitter is directed to the light receiver at a constant rate due to the reflection on the glass surface. The control device of the light emitter and the signal conversion circuit of the light receiver are omitted for simplicity.

FIG. 3 is a plan view. FIG. 3 illustrates the operation of the present invention on clouded glass.
Light from the light emitter diffusely reflects or scatters due to minute water droplets that cause haze, so that the light reaching the light receiver decreases as compared with the case where there is no haze. Therefore, the intensity of light entering the photodetector may be converted into an electric signal for determination. The control device of the light emitter and the signal conversion circuit of the light receiver are omitted for simplicity.

FIG. 4 is a plan view in which this principle is applied to the transmitted light of glass. The control device of the light emitter and the signal conversion circuit of the light receiver are omitted for simplicity.

[Explanation of Codes] Arrows other than the arrow pointing to the water droplet indicate the path of light from the light emitter. The names of other components are as shown in the figure.

Claims (1)

[Claims] 1. A glass fogging detecting device for an automobile, comprising a combination of a light emitter (1), a light receiver (2), a light emitter control device (3) and a light reception signal converter (4).