Optical interface for infrared monitoring of transparent screen - uses optical waveguide to couple light from IR source onto screen and has photodetector receiving reflected light fed via second waveguide

摘要

The optical interface includes an infrared light source (IRQ) which feeds light via an optical waveguide (LWL/S) into the inside of the interface where it illuminates the surface of the screen. The radiation reflected from the screen is received into another optical waveguide (LWL/E) and fed to a photodetector via a daylight filter (PD). The inside of the interface is filled with a material of suitable optical characteristics. The IR source and the photodetector are arranged in a housing including electrical circuitry. A temperature sensor is provided in thermal contact with the screen, and suppresses a spray device in case of freezing. USE/ADVANTAGE - For detecting wetness and dirt for triggering cleaning equipment, e.g. wipers. Interface is purely optical.