JOURNAL OF THE ILLUMINATING ENGINEERING INSTITUTE OF JAPAN
Online ISSN : 1349-838X
Print ISSN : 0019-2341
ISSN-L : 0019-2341
Volume 95 , Issue 8A
Showing 1-4 articles out of 4 articles from the selected issue
Original Papers
  • Kazuaki Ohkubo, Yasuo Nakagawa
    2011 Volume 95 Issue 8A Pages 431-438
    Published: August 01, 2011
    Released: October 19, 2011
    JOURNALS FREE ACCESS
    To measure the quantum efficiencies of lamp phosphors, a JCSS (Japan Calibration Service System) traceable measurement method that uses a polychromator, with improved optical design to reduce stray light, and an integrating sphere has been developed. To verify the measurement accuracy of this method, a monochromator, which has a 0 - 45°incident optical system, was used. The BRDF (Bidirectional Reflectance Distribution Function) of the phosphor was measured by a goniophotometer. A comparison was made between these JCSS traceable measuring devices on the 260-400 nm wavelength characteristics of the internal quantum efficiency of the blue phosphor BAM  (BaMgAl10O17:Eu2+) , which has excitation characteristics up to 400 nm. The results agreed within 4 % of the difference of the measured values. This is a good agreement considering that it was a composite measure and that the uncertainty of the spectral irradiance standard in the spectral region is lower than 3 %. It has also been established that the proposed method using a polychromator and an integrating sphere shows sufficient measurement accuracy.
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  • Kyoko Ishida, Youko Inoue, Hironobu Utiyama, Junichi Kurata
    2011 Volume 95 Issue 8A Pages 439-445
    Published: August 01, 2011
    Released: October 19, 2011
    JOURNALS FREE ACCESS
    This study investigates how the season and the correlated color temperature affect the impression of lighting. However, subjective evaluation inevitably has individual variation. Therefore, the purpose of this paper is to clarify how within- and between-subject variation changes. The experiment variables are the season, the illuminance of the room, and the correlated color temperature of the fluorescent lamp. The seasons are summer and winter, there are 12 levels of vertical illuminance of the room from 0.5 to 2000 lx, and the correlated color temperature of the lamps are 3000 and 6700 K. The subjects are 27 to 31 young women. They evaluate brightness, glare, comfort, and relaxation effect of the lighting. In conclusion : 1) Brightness, glare, and comfortable sensations change depending on the illuminance. The influence on the relaxation effect due to the illuminance is small, and the relation is clear for each individual. The subjects have suitable illuminance levels for relaxation. 2) All four items are influenced by the change of illuminance level in between-subject variation. The range of illuminance in which the evaluation between subjects stabilized is as follows: brightness is 500 lx or more, glare is 50 lx or less, comfort is from 20 to 50 lx, and relaxation is from 10 to 20 lx. 3) The variation between individuals is larger than the variation for each individual, though there is little difference with changes in illuminance.
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