JPS57100327A - Optical temperature measuring device - Google Patents

Abstract

PURPOSE:To eliminate measurement errors owing to fluctuations in light power by irradiating the light of the wavelength of the transmittance changing dependently upon temps., and the light of causing no change in the transmittance dependently upon temps. to a semiconductor temp. detector, and measuring the temp. from the ratio therebetween. CONSTITUTION:When the light lambda1 having energy of the value approximate to the energy hand gap of a semiconductor material constituting a semiconductor temp. detector 2 and the light lambda2 of long wavelength having the energy lower than said energy band are irradiated simultaneously to the detector 2 through optical fibers 41, 42 from two light emitting parts 11, 12, there is no temp. dependency of the absorption coefft. of the detector 2 by the light of low energy, that is, the light lambda2 of long wavelength out from the part 12 and only the temp. dependency of the optical fibers or the like is detected. Hence, if the light energies of the above-described two wavelengths are converted respectively to electric signals and the ratio between the two electric signals is detected, the temp. of the area where the detector 2 is placed is measured.