Capacitive rain sensor for windshield

Abstract

The basic windshield assembly 10 is well known and includes an outer layer 12 of glass and an inner layer 18 of glass with a sheet of transparent plastic 24 sandwiched between and bonded to the layers 12 and 18 of glass. A metal oxide coating 26 is disposed between the outer layer 12 of glass and the plastic sheet 24 as well known in the art and is transparent for filtering light, and is also electrically conductive. Accordingly, the assembly 10 is characterized by an isolated section, generally indicated at 28, of the coating 26 being electrically separated from the remainder of the coating 26 for capacitively sensing the presence of moisture on the outer surface 14 of the outer layer 12 of glass. The isolated section 28 of the coating 26 comprises a first plurality of electrodes 30 and a second plurality of electrodes 32, the first 30 and second 32 plurality of electrodes being parallel, interdigitized or interleaved and spaced from one another. The capacitance may detected by a known circuit attached directly to the electrodes 30 and 32 or through a capacitive coupling with the electrodes.

Dependencies are inferred from the claim text.