Journal of Light & Visual Environment
Online ISSN : 1349-8398
Print ISSN : 0387-8805
ISSN-L : 0387-8805
Volume 12, Issue 2
Displaying 1-5 of 5 articles from this issue
Paper
  • Shiro OTAKE, Yoshihiro OHNO
    1988 Volume 12 Issue 2 Pages 2_1-2_7
    Published: 1988
    Released on J-STAGE: May 20, 2011
    JOURNAL FREE ACCESS
    Experimental equipment by which various waveform of light can be generated has been developed for the psychophysical research on human visual temporal characteristics. For the light source of the equipment, electrodeless fluorescent lamps using short persistence phosphors driven by UHF electromagnetic wave are employed. The various waveform consisting of sequential short light pulses of more than 250 microseconds long, is generated by a typical feedback control in which the waveform of the UHF signal is modified temporally, based on the result of the sequential comparison between the measured intensity of the light output from the fluorescent lamps and the value of the waveform data. With the above mentioned control technique, the performance of the system realized is: circular light stimuli of 200mm diameter, the maximum luminance of 2000 cd/m2; the luminous uniformity, 0.8 (minimum/maximum); light color of white (correlated color temperature 5400K).
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  • Teruo KANEDA
    1988 Volume 12 Issue 2 Pages 2_8-2_15
    Published: 1988
    Released on J-STAGE: May 20, 2011
    JOURNAL FREE ACCESS
    The rectangular discharge tube will be used for the back light source of a liquid crystal display for a personal computer or color TV because the uniform luminance over a wide range is expected. The optical characteristics of the positive column of the rectangular discharge tube depend on plasma parameters in there such as an electron temperature and an axial electric field. Therefore, it is important to investigate the relation between the optical characteristics and the plasma parameters in the rectangular discharge tubes. In this paper, the radial distribution of the radiation intensity and the spectral characteristics were measured as functions of gas pressure and discharge currents for a rectangular discharge tube. Then the plasma parameters were obtained. The gases used were neon and neon — oxygen mixtures. The tube used for measurement was rectangular profile of 2×4 [cm]. The current over the range 10 — 50 mA was examined. The gas pressure was varied from 0.1 to 7 Torr. Then the experimental results were discussed qualitatively.
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Research Note
  • Spatial Frequency Component in a Corrugated Wave Pattern
    Naoyoshi NAMEDA, Toyohiko HATADA
    1988 Volume 12 Issue 2 Pages 2_16-2_23
    Published: 1988
    Released on J-STAGE: May 20, 2011
    JOURNAL FREE ACCESS
    The purpose of illumination is to allow solid perception to be obtained and depicted by a shaded pattern produced by lighting. The shading cue, as one of solid perception cues, was investigated, using a computer graphic device: Tospix-2. The corrugated wave was chosen for a test pattern, because an alternately bright and dark pattern, produced by shading, could be conveniently analyzed into contained spatial frequencies. This paper reports spatial frequency properties contained in the shading pattern. The shading patterns, which were actually shaded or were produced by computer simulation, were analyzed by Fourier Transformation by the same device. The result of the analysis indicates that the third through higher harmonics components are important. For observation of a solid shape, flat planes are assumed to be on the bottom of the completely curved solid perception. As apparent evidence for this assumption, under difficult visual conditions, a flat paneled figure was seen, in spite of the curved solid.
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Committee Report
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