Mode transition thresholds between the surface-color and the aperture-color modes of chromatic stimuli were examined. The luminance of the chromatic stimuli on a CRT display was kept constant, and the illuminance of an experimental booth including a subject was varied. The relationship between the mode transition thresholds and brightness-to-luminance (B/L) values of the stimuli was examined in experiment 1, and the relationship between them under a different illuminant was examined in experiment 2. The results of experiment 1 showed that the mode transition thresholds changed with the stimulus chromaticity and correlated highly with the B/L values of the stimuli. Moreover, the values of the mode transition thresholds depended upon not only the stimulus chromaticity but also the experimental method. That is, the values obtained with the constant chromatic stimuli method adopted in the present study were smaller than those with the variable chromatic stimuli method in previous studies. In addition, the results of experiment 2 showed that the mode transition thresholds correlated highly with the B/L values irrespective of the illuminant chromaticity. The results of experiments 1 and 2 lead us to the conclusion that mode transition perception is closely connected with a brightness perception mechanism.
The luminance and luminous flux of external-electrode, mercury-free, Xe flat discharge fluorescent lamp for LCD backlights and lighting equipment are equivalent to those of conventional Hg fluorescent lamps. However its efficacy is lower. In this paper, improvement of efficacy was attempted. First, the electrode width was reduced from 1.0mm to 0.5mm in order to widen the operating pressure margins. This enabled the Xe partial pressure to be increased from 1.2 kPa to 3.0 kPa, which increased efficacy 60%. Then a MgO, which has a high secondary electron emission coefficient, was coated on the dielectric layer, improving efficacy a further 10%. As a results, an efficacy of 35 lm/W with a luminance 10,100 cd/m2 were obtained with a 2.8-inch diagonal lamp.
Minimizing our negative on the environment is a global topics of interest. Achievement of high luminous flux. Maintenance is needed for the manufacture of environmentally friendly fluorescent lamps. At first, using multiple linear regression analysis, the relation of phosphor and protective layer thickness with the luminance flux maintenance is clarified. Next, the prediction formula of luminous flux maintenance is made and it is shown that a prediction formula agree with experimental results.