Patent attributes
An optical window contamination detecting device capable of detecting even microscopic contamination on an optical window with a limited number of contamination detecting sensors. The optical window contamination detecting device is used for a scanning type distance measuring apparatus that includes a casing, formed with an optical window, which accommodates a light transmitting unit, a scanning mechanism for deflection scanning measurement light output from the light transmitting unit into a measuring space through the optical window, and a light receiving unit for detecting reflected light from an object through the optical window. The optical window contamination detecting device includes a plurality of reflection photoelectric sensors arranged along the optical window on an outer side of the optical window and a retro-reflective member attached to the scanning mechanism, the retro-reflective member for reflecting detection light from the reflection photoelectric sensor having passed through the optical window towards the reflection photoelectric sensor.
