Patent ID: 8471513

Claim:
A rain sensor for detecting rainfall during rain comprising: a light source ( 5 ) radiating signal light according to a generated signal in a transmitter ( 11 ); a light receiving element ( 6 ), located in a unit sensing area and arranged with surrounding four light sources ( 5 ), for receiving light and facing towards a reflected light from raindrops caused by the radiated light of the light sources ( 5 ); an infrared filter installed in an opening formed at one side of a housing ( 1 ) of the rain sensor; and a receiver ( 9 ) excluding noise components caused by a reflection from a surface of a windshield ( 2 ) and extracting only a modulated frequency component of an optical signal to determine the amount of existing raindrops on the surface of the windshield so as to minimize an effect of ambient light and enhance a raindrop sensing probability wherein the light receiving element directly receives the reflected light, and wherein the light source ( 5 ) and the light receiving element ( 6 ) are mounted on a substrate ( 4 ), and the substrate ( 4 ) is inclined with respect to the surface of the windshield ( 2 ) such that the light source ( 5 ) the light receiving element ( 6 ) are inclined with respect to the surface of the windshield ( 2 ), and the light source ( 5 ) and the light receiving element ( 6 ) are disposed serially along a same direction.