JOURNAL OF THE ILLUMINATING ENGINEERING INSTITUTE OF JAPAN
Online ISSN : 1349-838X
Print ISSN : 0019-2341
ISSN-L : 0019-2341
Volume 83, Issue 8
Displaying 1-7 of 7 articles from this issue
  • Miki Goto, Takayuki Sakai, Kiyoshi Ohtani, Toshihiko Arai
    1999 Volume 83 Issue 8 Pages 521-525
    Published: August 01, 1999
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    The electron temperature and electron density in the tube axis of a low-pressureAr-Hg discharge lamp with 4-mm inner diameter were measured under various bath temperatures using a probe method. Theelectron temperature decreased from 2 to 1 eV in bath temperature region from 0 to 80°C. The electron density had a minimum at about 50°C. The Hg+ion, Hg metastable, and Ar metastable densities were measured using a modified absorption method. The Hg ion and Hg 6p3P0, 2 densities increased with bath temperature and saturated above 60°C. The Hg molecular ion density was determined by combining the modified absorption and probe methods. The Hg ionization rate caused by Penning ionized collisions between Ar metastables and Hg atoms was maximum at about 30°C.
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  • Sun-Young LEE, Kotaroh HIRATE
    1999 Volume 83 Issue 8 Pages 526-533
    Published: August 01, 1999
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    For both uniform and non-uniform lighting, we investigated user's preferences for wall surface illuminance compared with table surface illuminance, in order to obtain guidelines for comfortable use.
    In an interior space, the wall surface in the user's visual direction is an important surface that sometimes stops visual direction. In this case, the user tends to excessively observe the floor surfacebetween the walls in front of the user.
    For example, wall surface illuminance is influenced not only by table surface illuminance, but also by the brightness around the table.
    Then, for both uniform and non-uniform lighting, the desirable wall surface illuminance to the table surface illuminance was clarified in this research.
    It became clear that the relationship between the table surface illuminance and the wall surface illuminance is exponential, so it shows little difference between uniform and non-uniform lighting. And, it can be understood that the exponent of a non-uniform lighting is smaller than uniform lighting.
    In a non-uniform lighting, the maximum or optimum value of the exponent is in the range from 0 to 0.1 and it can be seen that this value tends to produce stable illuminance, independent of the table surface illuminance.
    Otherwise, in a non-uniform lighting, the preferable wall surface illuminance isslightly, influenced by table surface illuminance. For non-uniform lighting in which the area around the table is dark, it can be considered that the wall surface illuminance is influenced more by the darkness of the table area than by the brightness of the table surface.
    Furthermore, as a reference for lighting design, recommended values of preferable wall surface illuminance are shown in the full paper for 400, 700, and 1000 lx of table surface illuminance.
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  • Takanori Fujii, Hideo Fujikake, Kuniharu Takizawa, Tsunehiro Hirabayas ...
    1999 Volume 83 Issue 8 Pages 534-542
    Published: August 01, 1999
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    New types of light-controllable luminaires using a metal halide lamp or a Xenon lamp with a liquid crystal light shutter have been developed and demonstrated for spot or beam spot lighting of television program production. We fabricated a novel liquid crystal light shutter using a heat-resistant composite film of polymer and liquid crystal materials with a wide range of operating temperatures up to 150°C. The light shutter can modulate a strong luminous flux from the high-intensity discharge lamps, instead of a conventional mechanical shutter which has problems such as generating acoustic noise and being slow and heavy. The light modulation of the light shutter is based on a light scattering effect and the degree of scattering is controlled by the voltage applied to the shutter. It exhibits attractive features such as high transmittance, high-speed response, and high extinction ratio. The luminous intensity of an object could be varied continuously using the luminaires with the shutter, and the chromaticity deviation was drastically decreased by driving it with pulse width modulation.
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  • Yoshio Watanabe
    1999 Volume 83 Issue 8 Pages 543-547
    Published: August 01, 1999
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    A method of estimating the plasma temperature in a thermal equilibrium plasma from the measured discharge voltage and current waveform is introduced. The model consists of the discharge current and the energy balance equations. The target plasma is the lamp plasma in a high-pressure Hg or Na lamp. The appropriate plasma temperature can be estimated if the resonance radiation potential is used as the average excitation potential. The discharge voltage waveforms calculated from the obtained coefficients show good agreement with the measured ones. However, it is not clear why the resonance radiation potential should be used as the average excitation potential even for a Hg-lamp.
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  • Hidetaka Komatsu, Shu Takeshita, Toshibumi Sakata, Masako Sasaki
    1999 Volume 83 Issue 8 Pages 548-555
    Published: August 01, 1999
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    Spatial distribution of sky radiance needs to be measured to understand the exact influence of solar ultraviolet-B (UV B: 290320nm) radiation on humans, animals, plants, and materials. For this purpose, a solar UV-B sky radiance meter was developed and has been used since August 1996. The spatial distribution of solar UV-B sky radiance under clear skies showed quite different patterns from those of solar total (TOTAL: 300-3000nm) sky radiance, being more uniform. From the measured data, an empirical formula for the spatial distribution of solar UV-B sky radiance under clear skies was derived using three parameters: solar elevation ranging from 28° to 72°, angle of sky location from the horizon, and scattering angle between sky location and the sun.
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  • Katsunori Okajima
    1999 Volume 83 Issue 8 Pages 556-560
    Published: August 01, 1999
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    It is well known that old people generally need brighter illumination in daily life than young people. One of the reasons may be the decrease in retinal illuminance caused by age-related declines of ocular spectral transmittance and pupil response. I introduce a conversion method for calculating an equivalent illuminance which provides an equal retinal effective-illuminance between different ages. The conversion formula is an approximate solution of the equation for retinal effective-illuminance, and is expressed in a simple and convenient style, so it does not require any iteration or complicated calculation to derive the equivalent illuminance. Results calculated using the formula show that a 70-year-old person needs more than twice as much illuminance as a 22-year old. I believe that this formula relating age and illuminance will be useful for making practical standards concerning comfortable illumination environments for old people, and for investigating the aging mechanisms of human vision.
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  • Norihiro Yunoue, Kazurou Harada, Yoshiyuki Ishihara, Toshiyuki Todaka, ...
    1999 Volume 83 Issue 8 Pages 561-569
    Published: August 01, 1999
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    This paper presents a self-excited electronic ballast for electrodeless fluorescent lamps which is operated at 10MHz. The proposed circuit is based on a Class-E oscillator. However, the usual series inductor is removed from it so that a high no-load-voltage to strike an electrodeless fluorescent lamp is easily acquired. It employs a single switching device and realizes a decrease of the number of components. An analysis using higher harmonics with an equivalent circuit is presented. The waveforms calculated and measured using the optimum component values given by this analysis showed very good agreement both while running and before discharging.
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