Expansion of the measurable range in temperature measurement using a thermo-chromic liquid crystal (A method focused to the spectrum intensity in narrow-band wavelengths)

This paper describes the expansion of the measurable range of the temperature measurement method using a thermo-chromic liquid crystal. At first, we investigated the relationship between the profile of the spectrum intensity of the scattered light from the surface of the thermo-chromic liquid crystal and the temperature. A halogen light source with an infrared cutoff filter was used as the irradiation light source. Results show that the spectrum intensity of the scattered light increased monotonically with temperature in the range of wavelength shorter than 450nm, and the temperature could be identified by measuring the spectrum intensity of only a single specific narrow-band wavelength. The range of the measurable temperature of the method using this relation was validated using a monochrome-camera and narrow band-path filter of 442nm with FWHN=10nm. It was found that the measurable temperature range became about two times broader than that of conventional methods. In addition, the application of this method to the measurement of the two-dimensional temperature distribution was performed and temperatures with the range wider than that of conventional methods could be measured.