| 摘要 |
PURPOSE:To use a temperature sensor even in an explosive atmosphere and to eliminate the influence of an electromagnetically induced noise by using a material which varies in refractive index by temperature by utilizing light and detecting temperature by the deflection of the light. CONSTITUTION:When the temperature of a body to be measured is below a specific value, light from a light emitting element 11 is incident to the 1st refractive index layer 5 from a light emission part 7 through an optical fiber 9 and a critical angle thetath becomes smaller than theta because the refractive index n2 of the 2nd refractive index layer 6 is larger, so light L is transmitted through a boundary surface A. A the temperature of the measured part becomes higher and higher, the refractive index n2 of the 2nd refractive index layer 6 becomes smaller and smaller, and when the critical angle thetath becomes smaller than theta, the light is reflected by the boundary surface A. Then, this light L is received by a photodetection part 8 and transmitted to a photodetecting element 12 through an optical fiber 10 to output an output signal. This output signal when inputted to a comparator 13a is compared with a reference signal to output a detection signal. Consequently, the temperature is measured by the simple structure without any countermeasure to explosion, and the objective measurement range is widened. |
