Raindrop sensor

Abstract

An object of the present invention is to provide a raindrop sensor for sensing raindrops during rain, including a light source (5) for radiating light such that the light is transmitted through a vehicle window (2), a light receiving element (6) for sensing an optical signal when the light radiated from the light source (5) is reflected from the raindrop fallen on the vehicle window (2) and performing a photoelectric transduction, and a receiver (9) for receiving the photoelectrically transduced signal from the light receiving element (6) and judging the level of rainfall. The light source (5) and the light receiving element (6) are inclined with respect to the surface of the vehicle window (2) such that the light of the light source (5) directly reflected from the vehicle window (2) exits to the outside of the light receiving element (6) and the light reflected from a raindrop (8) on the vehicle window (2) is received by the light receiving element (6) to operate a vehicle wiper.

Description

technical field [0001] The present invention relates to a raindrop sensor attached to a windshield for determining the level of rain by receiving the amount of light reflected from raindrops falling on the windshield to which the sensor is attached towards a light source. [0002] The present invention also relates to a raindrop sensor that is not affected by ambient light other than light signals reflected from raindrops, thereby improving the sensing efficiency of rainfall levels. Background technique [0003] So far, conventional raindrop sensors have used a method in which light signals are directed toward the windshield to pass through the windshield to a light-receiving element attached to the opposite side of the light source to detect when raindrops fall on the windshield. Decrease in the amount of guided light to determine the level of rain; Send tilt signal light to the windshield to reach the light receiving element attached to the opposite side of the light sourc...

AI Technical Summary

Problems solved by technology

The disadvantage of the third method is the narrow sensing area of ​​the light source and light receiving element group, because multiple light source and light receiving element groups are required to detect raindrops falling on a wide area due to the serial arrangement of the light source and light receiving element

The disadvantage of the third method is the narrow sensing area of ​​the light source and light receiving element group, because multiple light source and light receiving element groups are required to detect raindrops falling on a wide area due to the serial arrangement of the light source and light receiving element

[0008] Even in the products developed to solve the above problems, the expected sensing efficiency performance cannot be achieved due to a decrease in SNR due to a large amount of reflection from the windshield other than the light signal reflected from raindrops

[0009] In addition, in the conventional method, the light signal caused by the alternating action of the wiper is also received; thus, the sensing efficiency becomes poor because of the influence of the headlight from another person's vehicle

In other words, in the operation of the wipers, in addition to light reflected from raindrops, headlights from another person's vehicle can also be received, resulting in misoperation, etc.

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