| 摘要 |
PROBLEM TO BE SOLVED: To detect easily abnormal temperature of an object to be measured and to select a light source freely without restrictions by a simple construction. SOLUTION: First and second optical fibers 2 and 4 are connected to a light source 1 and a photodetector 3 respectively and the first and second optical fibers 2 and 4 and a third optical fiber 5 are connected together by a photocoupler 6. A temperature sensor 7 is provided at the fore end of the third optical fiber 5. This temperature sensor 7 is constructed of a bottomed vessel 9 constituted of a metal such as copper or aluminum, for instance, and having one end opened, a waterproof cap 11 constituted of rubber or the like, having a through hole 10 in the central part and inserted into the vessel 9 from the opening thereof, a temperature-sensitive part 12 which is constituted of a surfactant filled in a space formed inside the vessel 9 by the waterproof cap 11 and of which the color is changed to the density facilitating change in light absorption-scattering to a light of a specific wavelength by a rise in temperature and an optical reflector 13 which is provided at a position being opposite to the fore end face of the third optical fiber 5 inside the vessel 9. |
