WINDOW MOUNTED OPTICAL MOISTURE SENSOR HAVING LIGHT PIPES WITH DISTAL ENDS

摘要

Mounting of a sensing unit (17) upon the interior surface of a vehicle windshield (14) for detecting the presence of mois- ture upon the exterior surface and controlling operation of windshield wiper s (15) in response thereto is disclosed. The sensing unit comprises a block (18) in which angularly oriented bores (22) are disposed. Light pipes (23) in a first set of the bores commu- nicate with light sources (25) for transmitting light to the outer surface o f the windshield, and light pipes in a second set of the bores transmit light reflected from the outer surface to photodetectors (29) . The lower ends of the light pipes are coplaner with or raised slightly above the surface of the block which is to be secured to the windshield. The block is affixed to the interior surface of the windshield by a double faced adhesive interlayer which both securely adheres the block to the windshield surface and opti- cally couples the light pipes to the windshield.