| 摘要 |
PURPOSE:To ensure the space transmission path of an optical signal even when an obstacle exists by using a light receiving element to detect a reflected light from an optical signal radiating from a 1st light emitting element, thereby detecting the obstacle and using a 2nd light emitting element to obtain an optical signal emitting in a direction without any obstacle. CONSTITUTION:When the obstacle 27 such as a person intersects an optical path in the spatial transmission path of an optical signal 22, the optical signal 22 made incident on a light receiving device 20 is interrupted. In this case, since a weak reflected light 21 is generated by the obstacle 27, the reflected light 21 is detected by a light receiving element 14 and amplified into a large electric signal by an amplifier section 15. A control section 18 discriminates the production of the obstacle 27, an electric signal inputted from a terminal 26 is switched and fed to a driving section 17. Since a 2nd light emitting element 16 is provided to have an optical signal emitting in a direction different from the direction of the 1st light emitting element 12, the light reaches the rear side of the obstacle 27. Thus, a part of the optical signal 24 is made incident on the light receiving device 20, thereby ensuring the signal transmission system. |
