| 摘要 |
PURPOSE:To ensure the space transmission for an optical signal even when an obstacle stands in the way by sensing the obstacle, varying the radiation direction of an optical signal from a light emitting element and radiating the optical signal in a direction in which no obstacle exists. CONSTITUTION:Plural 1st and 2nd light emitting elements 12, 13 driven by an electric signal such as an audio signal radiate an optical signal 22, and part of the optical signal 22 is made directly incident in an optical receiver 19 in the normal state to establish the transmission system. For example, when an obstacle 20 such as a person crosses the optical path and interrupts the optical signal 22, a reflected light 23 by the obstacle 20 is detected by a photodetector 14, the control section 16 drives an electromagnet 17 to move the plural 2nd light emitting elements 13 in the direction of the arrow 21a. An optical signal 24 radiating from the 2nd light emitting element 13 is reflected on, e.g. an indoor wall face 18, the reflected light 25 reaches the rear side of the obstacle 20, made incident in the optical receiver 19 to ensure the signal transmission system. Thus, the signal transmission is ensured even at tentative interruption of the optical path. |
