Journal of Light & Visual Environment
Online ISSN : 1349-8398
Print ISSN : 0387-8805
ISSN-L : 0387-8805
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Volume 7, Issue 1
Displaying 1-8 of 8 articles from this issue
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Paper
  • Chemical reaction phenomena in a Sc-Na halide lamp
    Toshihiko ISHIGAMI, Hiroki SASAKI, Miki HONMA
    1983 Volume 7 Issue 1 Pages 1_1-1_6
    Published: 1983
    Released on J-STAGE: May 20, 2011
    DOIhttps://doi.org/10.2150/jlve.7.1_1
    JOURNAL FREE ACCESS
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    To improve lumen maintenance of the Sc-Na halide lamps, it is necessary to have a knowledge of tungsten tranport process. In this paper, two Scl3 reaction phenomena which initiate tungsten transport are described. The one is phenomenon which has relation with the reaction between Scl3 and SiO2,the arc tube material. The other is phenomenon which has relation with the reaction between Scl3 and ThO2,the electrode emitter. Tungsten moves from the electrode tip to the tube wall as the result of the first reaction. Tungsten accumulates onto the electrode tip as the result of the second reaction. These chemical phenomena were related to the chemical analysis of black deposit on the wall, the observation of electrode tip deformations, the estimation of Th amounts in the arc and the comparison of electrode tip temperatures.
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  • Capacitor ballast for a compact fluorescent lamp
    Yoshio WATANABE
    1983 Volume 7 Issue 1 Pages 1_7-1_14
    Published: 1983
    Released on J-STAGE: May 20, 2011
    DOIhttps://doi.org/10.2150/jlve.7.1_7
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    A capacitor ballast that provides stable operation for a special kind of compact lamp with a short discharge channel is described. Three capacitor ballasts modified to improve operating performance are studied. They are: a capacitor ballast with an additional discharge circuit, a capacitor ballast with a variable capacitor, and a capacitor ballast with small series inductance. Efficacy of the lamp using the modified capacitor ballasts is about 3 to 10% lower than the efficacy with a choke ballast. However, system efficacy for the modified capacitor ballast is nearly equal, or 14% higher than, the efficacy with a choke ballast due to low power dissipation in the capacitor ballast. Furthermore, the weight of the capacitor ballst is one sixth that of a choke ballast. A rapid starting circuit is also developed for the capacitor ballast.
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  • A measuring technique for spectral distribution of light sources using an acoustooptic tunable filter
    Chihiro MASUDA, Hideo TAKAHASHI, Katsuyuki SHUDO, Koh-ichi MIYAJI
    1983 Volume 7 Issue 1 Pages 1_15-1_22
    Published: 1983
    Released on J-STAGE: May 20, 2011
    DOIhttps://doi.org/10.2150/jlve.7.1_15
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    This paper describes the characteristics of spectrometer and the measuring technique for spectral distribution in the visible wavelength region using an Acoustooptic Tunable Filter (AOTF) employing a TeO2 crystal. The contents of this paper are summarized as follows: (1) The polarization properties of the diffracted lights of an AOTF are linear polarization. (2) The diffracted light distribution can be approximated to the Gaussian distribution. (3) The resolving power of the wavelength of the diffracted light is smaller than 3 nm. (4) The wavelength accuracy of the diffracted light is about 0.002 nm/kHz.(5) The error of the spectral distribution is less than ±1% over the range of 380∼500 nm and ±0.5% at the longer than 500 nm. (6) The wavelength and spectral transmittance of an AOTF can be controlled electronically without any mechanical means.
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  • Luminance distribution of clear sky and the resultant horizontal illuminance
    Tadahiko NAGATA
    1983 Volume 7 Issue 1 Pages 1_23-1_27
    Published: 1983
    Released on J-STAGE: May 20, 2011
    DOIhttps://doi.org/10.2150/jlve.7.1_23
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    This paper presents some formulae for the calculation of the luminance distribution of a clear sky and of the resultant horizontal illuminance. Both the luminance distribution of a clear sky and the resultant horizontal illuminance are mainly affected by the extraterrestrial sunlight illuminance, the altitude of the sun, and the transparency of the atmosphere. A formula for the luminance distribution of a clear sky has been derived through theoretical consideration upon these factors. The formula predicts the luminance in absolute values as proposed to the ClE formula for clear sky, which provides relative pattern of luminance distribution1). Obviously the horizontal illuminance from an unobstructed clear sky can be calculated from the luminance distribution of the sky by means of a fundamental formula for the calculation of illuminance. However, from a different point of view a relatively simple expression has been formulated for the calculation of the horizontal illuminance, by applying the factors which were used to develop the formula for the luminance distribution, but in a different way.
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  • Visual acuity as a function of luminance contrast of Landolt rings and adaptation luminance
    Koichi IKEDA, Koji NODA, Shoichiro YAMAGUCHI
    1983 Volume 7 Issue 1 Pages 1_28-1_36
    Published: 1983
    Released on J-STAGE: May 20, 2011
    DOIhttps://doi.org/10.2150/jlve.7.1_28
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    The purpose of this study is to investigate the visual acuity as a function of the luminance contrast of the test objects and the adaptation luminance. The test objects are Landolt rings with the luminance contrast from 3 to 92%. The observers, all with normal vision, judge the break orientations of the Landolt rings by guessing. Visual experiments are carried out according to the standard method of the visual acuity test. Results obtained are as follows.
    1. The resolvable visual angle θ can be expressed as a function of the luminance contrast C (%) and the adaptation luminance L (cd/m2),
    θ=(1.6293 C-0.3234(0.8034 C-0.1876+L1/4)4/L (minute)
    For practical use, following equation is derived as a simple and convenient formula to calculate the resolvable visual angle.
    θ=(1.7 C-1/3(0.85 C-1/5+L1/4)4/L (minute)
    2. As the luminance contrast of the test objects can not be discriminated below a certain adaptation luminance, the visual acuity is not defined and the above equations do not hold below this luminance. This threshold luminance is expressed as a fuuction of the luminance contrast; i.e.,
    L=2.974 C-1.7234 (cd/m2)
    3. The visual acuity in the vertical and the horizontal directions are slightly higher than those in the oblique ones irrespective of the luminance contrast of the Landolt rings.
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  • Spectral luminous efficiency functions for a ten-degree field in the mesopic range
    Ken SAGAWA, Keishiro TAKEICHI
    1983 Volume 7 Issue 1 Pages 1_37-1_44
    Published: 1983
    Released on J-STAGE: May 20, 2011
    DOIhttps://doi.org/10.2150/jlve.7.1_37
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    Mesopic photometry is one of the current problems of the CIE TC-1.4. The luminous efficiency function for mesopic vision has not been established yet, whereas the functions V(λ) for photopic vision and V'(λ) for scotopic vision have been already standardized. In the present study, we measured the spectral luminous efficiency functions in the mesopic range extensively to offer basic data for making photometry more visually meaningful. A direct brightness matching method of 10° field was employed. White light was used as a reference stimulus, and its retinal illuminance was varied from 0.01 to 100 photopic trolands in 0.5 log unit steps to cover the mesopic range. Spectral luminous efficiency function from 400 to 700 nm in 10 nm steps was measured for each retinal illuminance level. Data of seven subjects (19-23 yr old) were collected. It was shown that the function obtained changed gradually from the photopic function to the scotopic one as retinal illuminance decreased. The average and individual variation of seven subjects’ data were presented as basic data of luminous efficiency for mesopic vision. The change of the function due to the different contributions of photopic and scotopic functions was discussed according to the Ikeda-Shimozono’s formula.
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Research Note
  • Differential performance on a color-word interference task:
    the effects of controlled illumination levels upon verbal response latency
    Peter O. PERETTI
    1983 Volume 7 Issue 1 Pages 1_45-1_48
    Published: 1983
    Released on J-STAGE: May 20, 2011
    DOIhttps://doi.org/10.2150/jlve.7.1_45
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    When testing SS in previous research on a color-word interference task, the stimuli were generally said to have been presented in a well-lighted room, or with adequate lighting, or with a good light source, and the like. The present research attempted to find out the difference in performancce between: (a) SS performing the task under a level of illumination of 5 ft-c;(b) SS performing the task under a level of illumination of 150 ft-c, (c) their similarity or differences of performance when compared with a control group of SS performing the same task under a level of illumination of 50 ft-c. Results indicated significant differences in performance between the SS of the 5 and 150 ft-c groups when compared with the control group. Levels of illumination under which the color-word interference task is performed significantly effect performance.
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Technical Trend
  • Energy saving effects of integrated lighting utilizing daylight
    Mitsuru SAITO, Kanji SAKAI, Kiyotaka ENDO
    1983 Volume 7 Issue 1 Pages 1_49-1_56
    Published: 1983
    Released on J-STAGE: May 20, 2011
    DOIhttps://doi.org/10.2150/jlve.7.1_49
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    This paper presents the energy saving effects in a building having automatically controlled lighting utilizing daylight inside perimeter zone. We have developed a computer program that enables to calculate capital and energy cost of a building in order to estimate the energy saving effects, and calculated many cases under various conditions, such as four types of window ratio to wall (20%, 35%, 50%, 65%), three operation types of venetian blind, etc. Finally we estimated these energy saving effiects by using a two-dimensional vector on a graph, on which the abscissa shows capital cost required and ordinate energy cost. By means of this vector on the graph, building owners can easily understand the energy saving effects of an automatically controlled lighting system utilizing daylight.
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