SENSOR FOR DETECTING WATER DROPS

摘要

This sensor (100) for detecting water drops has: a light-emitting element (10) for emitting a detection light; a refracting portion (30) for refracting the detection light so as to enter a transparent plate; a photoreceptor element (70) for receiving the totally-reflected detection light at the interface between the transparent plate and the air; and a detector (90) for detecting increase or decrease in the detection light entering the photoreceptor element, to thereby detect a that water drop has deposited on the outside surface of the transparent plate. The refracting portion has a plurality of entrance faces (31b, 32b). The plurality of entrance faces are arrayed within the plane of the transparent plate from the light-emitting element towards the photoreceptor element, while establishing the distances that connect the light-emitting element and the plurality of entrance faces, in such a way that the detection light entering the plurality of entrance faces has uniform intensity. Uniform detection sensitivity is achieved thereby, and sufficient surface area of the detection zone is ensured.