Patent ID: 7309873

Claim:
A raindrop sensor for sensing a raindrop attached to a transparent panel, the raindrop sensor comprising: a light-emitting element, which faces the transparent panel, wherein the light-emitting element emits light toward the transparent panel; a light-receiving element, which faces the transparent panel, wherein the light-receiving element receives the light emitted by the light-emitting element; a light guide body, which is mounted on the transparent panel, wherein the light guide body includes: an input lens, which is formed on an input side of the light guide body, wherein the input lens is divided into a plurality of input lens segments, which are displaced from each other in a direction parallel to an optical axis of the input lens; an input side dividing surface, which divides adjacent two of the plurality of input lens segments and is flat; an output lens, which is formed on an output side of the light guide body, wherein the output lens is divided into a plurality of output lens segments, which are displaced from each other in a direction parallel to an optical axis of the output lens; and an output side dividing surface, which divides adjacent two of the plurality of output lens segments and is flat, wherein: the input lens collimates the light, which is emitted by the light-emitting element, to form an input side collimated light beam; the output lens receives the collimated light beam, which is collimated by the input lens and is reflected by a reference surface of the transparent panel, to which the raindrop attaches; the output lens converges the reflected collimated light beam toward the light-receiving element so that the light-receiving element receives the reflected collimated light beam; an intersection between an imaginary extension of the input side dividing surface and an imaginary extension of the output side dividing surface is located on the reference surface of the transparent panel; wherein the input side dividing surface extends along the optical axis of the output lens; the output side dividing surface extends along the optical axis of the output lens; and at least one of the plurality of input lens segments and the plurality of output lens segments includes: a single first radial side lens segment, which is located on a first radial side of the optical axis of a corresponding one of the input lens and the output lens is furthest from a corresponding one of the light-emitting element and the light-receiving element among the at least one of the plurality of input lens segments and the plurality of output lens segments; and a plurality of second radial side lens segments, which is located on a second radial side of the optical axis of the corresponding one of the input lens and the output lens and is closer to the corresponding one of the light-receiving element and the light-receiving element relative to the single first radial side lens segment.