| 摘要 |
PURPOSE:To prevent the incidence of the unnecessary reflected light to the photodetecting element and the offset transaction of output signals by forming the incident surface corresponding to two reflected surfaces of the optical conductive material slanted against the optical axis. CONSTITUTION:Incident surfaces 2u, 2v corresponding to two reflected surfaces 2a, 2b of an optical conductive material are slanted and carved so as not to become vertical against the optical axis which penetrates them. Consequently, the optical axis of a signal light where the signal light returned from an objective range is reflected on the incident surface 2u, 2v is shifted against the optical axis of the signal light. As a result an image T of the unnecessary reflected light is far outside and combined into a photodetecting element 5. Therefore, the occurrence of the offset transaction of output signals by the unnecessary reflected light can be prevented. |
