| 摘要 |
PURPOSE:To control the operation of a windshield wiper in accordance with the amount of raindrops in a highly accurate manner, by installing a light receiver taking light out of a floodlight installed outside a car, while having the light receiver made up of plural light receiving elements which get light in a way of dividing an image stripe-patterned by a slit plate into two parts, a bright part and a dark part. CONSTITUTION:A floodlight 1 built in a fender mirror 3 is lighted, and when such light as collected by a concave mirror, etc., is projected to a light receiver 4 attached to the backside of a room mirror 6 through a windowpane 11, the light receiver 4 receives light through a light detector 10 via a slit plate 9. That is, an image of the slit plate 9 is divided into two parts, a bright part and a dark part and then projected to each of bright and dark light receiving elements 10a and 10b of the light detector 10. At this time, it means that a difference in light receiving signals outputted from these light receiving elements 10a and 10b shows the degree of contrast for the said image according to each case when raindrops stick to the windowpane 11 or not. So, in response to this difference in the light receiving signals, the operating speed and cycle of a windshield wiper device are automatically constrolled.
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