| 摘要 |
PURPOSE:To achieve the higher reliability of the device and lower cost by coupling the controlled side and operating part by means of single optical fiber glass thereby eliminating the coupling portions of light. CONSTITUTION:The light reaching fiber glass 16 from a light emitting part 4 reaches optical fiber glass 20 and if a light shield plate 11 is not inserted in a gap 10, the light is again transmitted in the fiber glass 16. At this time, part thereof reaches the display bracket 18 of fiber glass 19. The light again transmitted to the fiber glass 16 is coupled to a photo detecting part 8 through fiber glass 15. In the photo detecting part 8, a control circuit 6 turns ON a control switch 7. On the other hand, when the light shield plate 11 is inserted into the gap 16, the light transmitted to the fiber 20 is shielded. Hence, in the photo detecting part 8, the control circuit 6 turns the control switch 7 OFF. Light is not transmitted to the display bracket 18 either. With such constitution, the reliability of the device is improved and the cost reduced. |
