Sensor

PCT No. PCT/DE95/00699 Sec. 371 Date Apr. 8, 1996 Sec. 102(e) Date Apr. 8, 1996 PCT Filed May 30, 1995 PCT Pub. No. WO96/05087 PCT Pub. Date Feb. 22, 1996The invention is directed to a measuring apparatus with a transmitter and a receiver which is arranged at a distance therefrom. Both the transmitter and receiver are optically coupled with a surface of the windshield of a motor vehicle in the region of the wiping area covered by a wiping mechanism, the region between the transmitter and the receiver forming a measurement path for a light beam which is transmitted into the windshield by the transmitter at the angle of total reflection and which is received by the receiver and fed to an evaluating device. The transmitter and the receiver are accommodated in a housing supported at the inner side of the windshield and are supported therein via a preferably shared supporting member. A measuring apparatus operating in a particularly dependable manner is achieved in that a heatable component whose plate-shaped portion is disposed directly opposite the measurement path is arranged in the housing which is at least partially open to the windshield, this component being formed of a material with good heat conducting properties and supported at the housing.