Patent ID: 7214911

Claim:
A system for detecting fogging of a glass windshield of an automotive vehicle comprising: a surface temperature sensor adapted to be mounted at a glass windshield of an automotive vehicle for detecting the glass surface temperature, Ts; a humidity sensor adapted to be mounted at a position spaced from the glass windshield by a predetermined distance for detecting the humidity H around the windshield glass; a peripheral temperature sensor adapted to be mounted inside of the windshield glass for detecting the peripheral temperature, Te, around the glass; and a signal deriving device for deriving (a) a first signal indicative of windshield dew point, Td, in response to indications of H and Tc, where Tc has a value adapted to be determined by an arrangement arranged to be responsive to combined values of Ts and Te,; and (b) a second signal indicative of the presence or absence of fog on the windshield, the second signal having a value adapted to be determined by an arrangement for comparing Td with Ts.