Patent ID: 7847255
Filing Date: 2010-12-07
Classification: B60S,G01N

Abstract:
1. An optical rain sensor for efficiently detecting moisture on a vehicle window having a thickness between 4-12 mm and a corresponding infrared radiation transmission comprising: an optical coupler into which optical elements are molded, wherein the optical elements comprise a plurality of lens segments for directing infrared rays, and further wherein, the optical coupler is mechanically and optically coupled to a major surface of the vehicle window having a thickness T, and infrared radiation transmittance Tir; a housing detachably mounted to the coupler; a circuit board mounted within the housing and being substantially parallel to the vehicle window; and electronic components mounted on the circuit board comprising at least two emitters of infrared radiation each producing rays over a 180° hemisphere substantially normal to the circuit board and at least two detectors of infrared radiation each detecting rays over a 180° hemisphere substantially normal to the circuit board; the plurality of lens segments being integrally molded into the optical coupler proximate, and at a height above, each of the at least two emitters and at least two detectors, whereby infrared rays emitted from the at least two emitters are collimated, and then directed, nonsequentially, in one or more of at least four optical paths by the plurality of lens segments through the vehicle window and back to the at least two detectors, wherein the specific optical path followed by the infrared radiation is dependent on T and Tir.