| 摘要 |
PROBLEM TO BE SOLVED: To provide a liquid surface sensor which is intended to miniaturize the sensor head and capable of detecting abnormal conditions of an optical path and an electric circuit. SOLUTION: A projecting optical fiber 12 and a receiving optical fiber 13 are downward held with a fixed block 17 provided in a tubular case 11 and the end faces of the optical fibers 12, 13 face a mirror surface 28. A light projected from the projecting optical fiber 12 is reflected on a transparent part 14A and the mirror surface 28 and received by the receiving optical fiber 13 when no liquid exists outside the transparent part 14A. Since both optical fibers 12, 13 are housed along the tubular case 11, there is no need to provide a space for curving the optical fibers, this being necessary for the conventional ones, and hence the sensor head 10 can be downsized. |
