Patent ID: 7230260

Claim:
A raindrop sensor, which is provided in a first surface side of a transparent body for sensing water attached to a second surface of the transparent body, the raindrop sensor comprising: a light emitting element that is provided in the first surface side of the transparent body for emitting light toward the transparent body; a light guide body that is mounted on a first surface of the transparent body, wherein: the light guide body guides the light, which is emitted by the light emitting element, to the transparent body; and the light guide body guides the light, which is reflected by the transparent body, to the first surface side of the transparent body; a light receiving element that is provided in the first surface side of the transparent body for receiving the reflected light, which is reflected by the second surface of the transparent body, the light receiving element outputting a signal based on an amount of the reflected light received by the light receiving element; and an abnormality determining device that determines an abnormality of the light guide body by comparing a value indicated by the signal outputted by the light receiving element with an index value.