AMBIENT LIGHT REJECTION ENHANCED RAIN SENSING APPARATUS IN ARRAY STRUCTURE

摘要

A rain drop detection apparatus arranged in a row for reducing the influence of an ambient light is provided to exclude noise elements by reflection on the surface of a windshield by disposing a signal light in the same direction as a light receiving device. A rain drop detection apparatus includes a light source(35), a light receiving device(36), an infrared filter(33), and a receiver. The light source transmits a signal light according to a signal generated in a transmitter. The light source and the light receiving device forms a pair. The light receiving device receives the light reflected by a rain drop and returning to the original position and is disposed in a row with the light source. The infrared filter is mounted to a slit(44) formed on one side of a rain drop detection sensor case. The receiver determines the amount of rain drops on the windshield by excluding noise elements by reflection on the surface of the windshield and extracting only modulated frequency components in the signal light.