JOURNAL OF THE ILLUMINATING ENGINEERING INSTITUTE OF JAPAN
Online ISSN : 1349-838X
Print ISSN : 0019-2341
ISSN-L : 0019-2341
Volume 72, Issue 6
Displaying 1-8 of 8 articles from this issue
  • Yoshito Kato, Hirokazu Ootake
    1988 Volume 72 Issue 6 Pages 293-294
    Published: June 01, 1988
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
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  • Tetsuya Muraoka, Mikiya Kawamura, Hiroe Uesako
    1988 Volume 72 Issue 6 Pages 295-300
    Published: June 01, 1988
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    The readability on the liquid crystal numerical display device with positive type 7 segments was examined under several conditions of circumstances, owing to investigate the visibility. The six samples were classified with respect to the manufactory and the size. The experimental conditions were established so that visual angle was limitted 0.5° to 1.25°, right-left visual direction angle was limitted 30° to 90°, up-down visual direction angle was limitted 0° to 90° and illuminance was limitted 0 lx to 300lx. Four experimental subjects read random indicativefigures with 0 to 9 in the dark room, which were presented for 0.1 second. The following results were obtained from the readability tests.
    (1) According the inclination of display board and the variation of illuminance, the visibility on liquid crystal display device was more influenced than printing figure with the visual direction angles.
    (2) The parametric curves concerning visual angle showed readabilities vs visual direction angles relations parallel shifted with the visual angles. Its shift was limitted to 30 with total variation ranges of the visual angles in up-down visual direction. And it was significant greater than 20° in the right-eft visual direction.
    (3) According to increase of the illuminance, the 100% visual direction angle increased 35° to 73° with the left directions, 42° to 80° with the right directions, 0° to 76° with the up directions, and0° to 48° with the down directions. In general the 100% visibility threshold of up-down visual direction angle showed less value than that of the right-left. And the threshold of down direction showed less value to one half than that of the up directions.
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  • Sen-ichiro Nakanishi, Tatsuhide Nakagawa, Toyoji Himei
    1988 Volume 72 Issue 6 Pages 301-306
    Published: June 01, 1988
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    The paper describes the simulation results of high pressure mercury lamps by a state variable equation model, and discussed for the reduction of the starting period of the lamp. At first, a set of equation model considering the thickness of a lamp bulb is shown in readjustment. The effect of changing single and complexcoefficients of equations for starting period is investigated. The coefficient of pattern on mercury vaporization, heat conductivity of mercury vapor, heat conductivity of enclosed gas in an outer bulb, and thickness of bulbs greatly affect the starting period. In order to change a initial value of the state variables, it needs to change whole values with balance. From the simulation results of preheating discharge lamp operation, we make it clear that the light output depend on effective plasma temperature and the speed of mercury vaporization.
    From above mentioned results, important factors to shorten the starting period of mercury lamps are (1) to raise plasma temperature quickly, (2) to shorten the mercury vaporization time. Considering these points, the authors try to discuss the quick rising methods of light output at lamp starting. Finally, the starting period can be reduced experimentally by controlling the lamp input power by adjusting the source voltage and the ballast impedance.
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  • Satoru Kubota, Makoto Takahashi
    1988 Volume 72 Issue 6 Pages 307-312
    Published: June 01, 1988
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    Two experiments were carried out to investigate the relationship between display luminance conditions and pupillary response.
    The first experiment attempted to determine whether or not peak luminance or integrated luminance played a greater role in determining pupil diameter. The result indicates that the pupil diameter to an irregular luminance field is biased significantly in the direction of the peak luminance. This suggests that the lighter of the two items, either background or the character, will essentially control the pupil diameter, thereby negating any effect on pupil size due to positive versus negative image.
    The second experiment attempted to investigate the effect of luminace ratio, between source document and screen, on pupil diameter and subjective fatigue. The result indicates that the difference between pupil diameter to source document luminance and screen luminance has more to do with the peak luminance of the screen than with the integrated luminance. Such a difference, even in the case of negative image displays, is not very large. This suggests that proposed lighting differences based on image polarity or recommendations of positive image polarity do not appear to be warranted.
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  • Masaharu Nakayama, Koichi Ikeda, Kiyoshige Obara
    1988 Volume 72 Issue 6 Pages 313-318
    Published: June 01, 1988
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    In 1943, the O. S. A. recommended the Munsell renotation system which was a revision of the original Munsell space systematized by A. H. Munsell using colour chips. However, it is not clear what mathematical analyses were applied in the process of the renotation.
    In this paper, the constant chroma loci and the constant hue loci on the CIE chromaticity diagram are approximated by means of quadratic functions. It is assumed that an constant chroma locus should be approximated by the elliptic curves not only have the centre coincided with the chromaticity coordinates of the standard illuminant C but pass through three consecutive chromaticity coordinates of the constant chroma with a spacing of 2.5 hue. On the other hand, the approximation of an constant hue locus is performed by the elliptic curves or the hyperbolic ones which pass through the coordinates of the illuminant C and other four consecutive chromaticity coordinates of the constant hue with a spacing of 2 chroma.
    These loci of the Munsell renotation system are found to be far from uniform, as many irregularities are found by this analysis.
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  • Yasuo Nakagawa, Fumio Ohtani, Masashi Hara, Teruaki Katsube, Tamaki Ya ...
    1988 Volume 72 Issue 6 Pages 319-323
    Published: June 01, 1988
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    Irradiance of 185 nm line radiation which is emitted by low pressure mercury vapor discharge, was measured in vacum and air. The measurement instrument was composed of Cs-Te phototube or pn type silicon photodiode detectors, interference filters and mesh type optical attenuters
    Relative spectral responsivity of detectors were measered by direct comparison of standard thermal detector under monochromatic irradiation (185-300 nm). Then absolute responsivity of 185 nm was estimated by the relative spectral responsivity and responce by meanse of 253.7 nm irradiance standard lamp. Transmittance of interference and mesh filters were also measured at 185 nm respectively.
    Irradiance in vacum was measured under about 3×10-2 torr. for 6 W low pressure mercury lamps at 16.1 cm measurement distance and absorption of air for 185 nm radiation was also estimated (about 74 % for 16.1 cm).
    Irradiance of 185 nm radiation in air were measured for three type low pressure mercury lamps at several distances. By comparison for irradiance of other mercury lines, which were not absorbed in air, absorption coefficient of 185 nm radiation in air was estimated.
    Rediation power ratio of 185 nm/254 nm was about 0.22 for low pressure mercury lamp with synthetic quartz tube.
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  • Katsuzo Itoh, Tarow Noguchi, Youko Inoue
    1988 Volume 72 Issue 6 Pages 324-331
    Published: June 01, 1988
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    Owing to the effect of light scattering in the eyeball, the actual luminance of the image on the retina is not the same as the nominal luminance of the viewing object. The inconsistency in present visibility analysis is originated in this fact.
    The actual luminance at the fovea is defined as effective luminance, and by introducing this effective luminance into visibility problems, the visibility analysis can be constructed on a single principle, and the estimation method of visivility can be rationalized and simplified.
    The basis of this study is the uni-dimensional effective luminance function F(θ), which represents the effective luminance distribution perpendicular to the borderline of the two planes having luminances 1 and 0cm/d2. The effective luminance for any visual target can be decided from F(θ), and the equi-visual-acuity charts can be known from it.
    Authers suggest that the many pending problems on visibility, such as adaptation luminance for non-uniform visual field, dynamic evaluation of visibility, bluring of the shape of the image on the retina, all can be understood clearly by use of the effective luminance conception.
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  • 1988 Volume 72 Issue 6 Pages 336
    Published: 1988
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
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