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Polyfluorene oriented films produced by a friction-transfer method show polarized blue-light emission. A subsequent doping of some types of fluorescent dyes into the oriented films using a vapor transportation method resulted in polarized emission from the oriented polymer and from the doped dye. Polarized photoluminescence spectra from the polyfluorene films doped with oligothiophenes, quaterthiophene, and sexithiophene showed that these materials exhibit marked dichroism caused by the alignment of the oligothiophene molecules parallel to the polymer chain. We succeeded in extending the wavelength range of the polarized emission by doping fluorescent dye into the films.

A five-band infrared radiometer has been developed for the measurement of spectral radiance and radiance temperature at low temperatures. The optical system of this radiometer consists of a scanning plane reflecting mirror, five narrow-band interference filters in the 6–12 μm band, a mirror-type rotating chopper, a cold source, a hot source, and a HgCdTe semiconductor detector. Measurement of radiance temperature and spectral radiance using this radiometer is carried out automatically using a personal computer. The calibration of the output signal for each spectral channel of the radiometer is carried out exactly using a blackbody source with an accurate temperature controller. The short-time stability of the radiometer is estimated to be within 0.2% mean deviation for the main spectral channel. The temperature detection sensitivity of a radiometer is evaluated as the noise equivalent temperature difference (NETD) for the optical and measuring system; the NETD for the main spectral channel is estimated to be about <0.2 °C. The minimum detectable radiance for the main spectral channel is also estimated to be about <0.002 mW/cm2 sr μm. For confirmation of the long-time stability of the radiometer, the measurement of the radiometer output ratio between the blackbody source at a temperature of 15 °C and the hot source at a constant temperature of 40 °C is carried out over 3 h; the long-time stability of measurement for the main spectral channel is estimated to be within ±0.3 °C mean deviation. The variation over time of the spectral radiance and the radiance temperature of the cloud in the sky was actually measured using the radiometer, and its usefulness was clarified.

The fundamental procedure involved in the two‐monochromator method for determining the spectral radiance factors of fluorescent materials is described, and some measured results are presented. The colorimetric accuracy of the method was confirmed by comparing two sets of tristimulus values: (1) those based on the two‐monochromator method and calculated from the reflected and the fluorescent spectral radiance factors and the spectral power distributions of a tungsten‐halogen lamp and a xenon lamp (which were determined separately); and (2) those calculated from the total radiance factors obtained from the measurement under polychromatic illumination, where the fluorescent materials were irradiated with the tungsten and the xenon lamp. The color differences between these sets of tristimulus values in CIE‐LUV color space were estimated to be less than 1.0 unit, irrespective of the illuminant or the source.

This article describes a method for the prediction of the reflected and the fluorescent spectral radiance factor which are expected to be measured by use of a measuring system with polarizing properties, and a method for the estimation of the spectrophotometric errors in the predicted radiance factors. Polarization properties are described for the measuring system, the white standard surface, and the two kinds of fluorescent samples used in the two‐monochromator method of the present study. In this method, the spectrophotometric errors in the reflected spectral radiance factor are estimated to be not less than 1% at some wavelengths. However, the error of the fluorescent spectral radiance factor is relatively small. Colorimetric errors of fluorescent samples due to polarization are estimated for the one‐ and two‐monochromator methods. The errors expressed as CIELUV color differences are estimated to be less than 1.0 unit and are negligibly small.