| 摘要 |
PURPOSE:To improve reliability by drastically reducing the number of parts by forming a circuit for leading the signal of a detector to an optical system using half mirrors. CONSTITUTION:When an optical phenomenon generates, the output signal of a detector among detectors 20a-20c is connected as light signal with an optical circuit 22 through optical connection parts 21a-21c. The light signal is distributed through half mirrors 23a-23c, and inputted into a logic discriminating circuit 29 through photoelectric converters 26a and 26b. In this case, if the critical phenomenon is detected by at least two detectors 20, the electric signal corresponding to the light quantity is generated in the photoelectric converters 26a and 26b, and the input signal of a judging circuit 29 is set H, and the generation of the critical phenomenon is detected. Since a logic circuit in the 2/3 decision by majority is constituted of a circuit 22 in the combination of half mirrors 23a-23c which can be used nearly permanently, reflection mirrors 24a-24c, reflection mirrors 27a-27c, and reflection mirrors 28a-28b, the number of parts can be reduced, and reliability can be improved.
|
