| 摘要 |
PURPOSE:To save power consumption by detecting the reflected light of an optical signal emitting from plural light emitting elements to a space in various directions with a light receiving element provided in the vicinity of each light emitting element, driving or stopping the light emitting element in response to the quantity of detection or controlling its light emission quantity. CONSTITUTION:Optical signals 32, 34 emitting from light emitting elements 12, 14 are interrupted by an obstacle 36, reflected lights 33, 35 are detected by light receiving elements 19, 20 and a control section 26 stops the drive of the light emitting elements 12, 14. The two light emitting elements among the three light emitting elements 12-14 are affected by the obstacle 36, stop the light emission and since the optical signal from the light emitting element 12 is attenuated by the reflection on a wall face 28, the light emitting element 12 causes a larger current than the normal current to flow in response to the number of the light emitting elements stopping the light emission, the light emission output is increased to ensure the quantity of the optical signal reaching the light receiving device 29. |
