| 摘要 |
Temperature measuring apparatus using the material whose light transmittancy depends on temperature. This apparatus uses either light having a first wavelength at which the transmittancy depends on temperature when passing through a temperature sensor (9) and light having a second wavelength at which the transmittancy is constant with no relation to temperature, or two lights having first and second wavelengths at which the transmittancies change differently from each other depending on temperature. The ratio of the signal showing the intensity of the light of the first wavelength after passing through the temperature sensor (9), to the signal showing the intensity of the light having the second wavelength is obtained for measurement. Thus, it is possible to obtain a temperature measuring apparatus with high accuracy, since the output is not influenced even though the coupling efficiency between the optical fibers and the temperature sensor and the propagation losses in the optical fibers change. The invention is suitable for a temperature measuring apparatus with a low and middle temperaturerange in environments including high voltage, high magnetic fields, a chemical atmosphere, and others. |
