PURPOSE: To enable a car window to be wiped in responce to the amount of rainfalls by making use of plural detector elements, and automatically controlling a wiping speed according to a ratio between the number of effectively operating detector elements and that of those issuing a signal responding to the actual adhesion of a liquid fraction.
CONSTITUTION: Optical sensor elements 1 each being a detector and light emitting elements 2 are bonded and fixed in pairs on the inside surface of a window shield 3 via prisms 4, 5, and rainfalls are detected by the reduction of light received by the optical sensor element 1 when the rainfalls 6 adhere near the refracting point of the light emitted from the light emitting element 2. A detecting device A is constructed by arranging such plural optical sensor elements in parallel, and output signals from the respective optical sensor elements 1AW1N are inputted to a CPU 13 after being selected in order by a multiplexer 8 and amplified, etc. And, a wiping speed is determined according to the number of optical sensor elements 1AW1N to each of which a liquid fraction actually adheres, allowing the number of revolution of wiping motor 14 to be controlled.
SASAGE HIDEHIRO
WATANABE TAKASHI
