| 摘要 |
<p>PURPOSE: To provide an optical device capable of miniaturization and massproduction which can detect a return light by a constant operation, indepen dently of the state of a return light. CONSTITUTION: The laser light outputted from a laser light source 3 like a semiconductor laser is reflected by an object to be irradiated and a return light is obtained. A reflecting mirror 11 is arranged in the vicinity of the focal point position. Photodiodes PD1 A, PD2 A, PD3 A, PD1 B, PD2 B and PD3 B as photo detecting parts are arranged facing the first and the second reflecting surfaces MA, MB of the reflecting mirror 11. The reflecting surfaces MA, MB are arranged so as to reflect a part of the return light, and signal is detected in the photo detecting parts.</p> |
