| 摘要 |
<p>An optical apparatus that lends itself to size reduction and mass production and enables detection of a return light beam by a pre-set operation irrespective of the state of the return light. The optical apparatus has a reflecting mirror (1) arranged in the vicinity of the focal point of the return light beam obtained on reflection by an illuminated object of the outgoing light from a laser light source 3, such as a semiconductor laser, and photodiodes PD1A, PD2A, PD3A, PD1B, PD2B and PD3B, as light receiving portions, arranged facing first and second reflecting surfaces MA and MB of the reflecting mirror (1). The reflecting surfaces MA and MB are arranged for reflecting a portion of the return light, while signal detection is performed by the light receiving portions.</p> |
