Patent ID: 7238935

Claim:
A light detection device for detecting detected light, the light detection device comprising: a main body; a light guide supported by the main body in a manner enabling the light guide to vibrate, the light guide including a distal end projecting from one side surface of the main body, wherein the distal end functions as a light incident portion through which the detected light enters and a light radiation portion from which visible light is emitted; a drive mechanism, arranged in the main body, for reciprocating the light guide in an X-direction while vibrating the light guide in a Y-direction that is perpendicular to the X-direction, wherein the distal end of the light guide moves within a light detection area in an XY plane; and a visible light-emitting unit, arranged in the main body, for emitting visible light from the distal end of the light guide when the detected light enters the distal end, wherein the visible light-emitting unit includes; a photo-detector, optically coupled to the light guide, for detecting the detected light from the light guide; and a light-emitting element for generating the visible light when the photo-detector detects the detected light.