Journal of Light & Visual Environment
Online ISSN : 1349-8398
Print ISSN : 0387-8805
ISSN-L : 0387-8805
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Volume 36, Issue 1
Displaying 1-7 of 7 articles from this issue
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Foreword
Papers
  • Electron Spin Resonance Study on Local Structure of Manganese Ions Doped in Gamma-Aluminum Oxynitride Phosphors
    Mamoru Kitaura, Ai Harima, Rong-Jun Xie, Takashi Takeda, Naoto Hirosak ...
    Article type: Paper
    2012 Volume 36 Issue 1 Pages 6-9
    Published: April 01, 2012
    Released on J-STAGE: June 19, 2012
    DOIhttps://doi.org/10.2150/jlve.36.6
    JOURNAL FREE ACCESS
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    We have studied the local structure of manganese ion doped in gamma aluminum oxynitride phosphors (γ-AlON: Mn) using electron spin resonance (ESR) experiment. Six sharp peaks appear in ESR spectra of γ-AlON: Mn, together with five weak doublets. These structures are caused by the hyperfine interaction of 3d electrons with the 55Mn nucleus of spin I=5/2. The six peaks are attributed to the allowed transitions (ΔMI=0) between hyperfine splitting states of Ms=±1/2. The five doublets are interpreted as the forbidden transitions (ΔMI=±1) between the hyperfine splitting states. The spectral feature of γ-AlON: Mn resembles with the ESR spectrum of Mn2+ doped MgAl2O4 spinel, in which Mn2+ ions are substituted for tetrahedral Mg2+ sites. Since γ-AlON is also of the spinel structure, it is suggested that Mn2+ ions occupy tetrahedral Al3+ sites. We further chased the effect of Mg2+ co-doping on ESR spectra of Mn2+ ions in γ-AlON, in order to elucidate the luminescence enhancement in γ-AlON: Mn, Mg. It turned out that the Mg2+ co-doping increases Mn2+ ions at tetrahedral Al3+ sites.
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  • Characteristics of the Brightness Perception under the Dark Adaptation
    —Aims to Develop Energy-Efficient Lighting System for Signboard—
    Kazuo Sendai, Mamoru Takamatsu, Yoshio Nakashima
    Article type: Paper
    2012 Volume 36 Issue 1 Pages 10-15
    Published: April 01, 2012
    Released on J-STAGE: June 19, 2012
    DOIhttps://doi.org/10.2150/jlve.36.10
    JOURNAL FREE ACCESS
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    Outdoor signboards on the street provide not only advertising but also effective scenery of the town, and they are useful for the activation of the town. Sometimes they have different faces according to the effect of the lighting systems in daytime and night time. In this experiment, we use lighted signboards to examine how human eyes see “object colors” under the dark conditions. Advertising signboards that we recognize as “object colors” begin to change into “light source colors,” when it darkens gradually in the night time. When this change occurs, the horizontal illuminance decreases from 1000 to 100 lx. In addition, “brightness feeling” and the ratio of “light source colors” rise rapidly when the luminance difference between the sky and signboard falls below 200 cd/m2. We think our results will be useful to develop and control signboard lighting in the field of energy saving technology.
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Research Notes
  • Daylighting and Its Impact on Depth Perception in a Daylit Space
    Nan-Ching Tai
    Article type: Research note
    2012 Volume 36 Issue 1 Pages 16-22
    Published: April 01, 2012
    Released on J-STAGE: June 19, 2012
    DOIhttps://doi.org/10.2150/jlve.36.16
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    Visual perception within a daylit environment changes according to spatiality, sky conditions, time, and the point of observation. This paper focuses on the complex interrelationships among the architectural configuration of skylights, luminance distribution patterns resulting from changing sky conditions, and the perception of spatial depth. This study employed lighting simulation techniques that incorporate physically based rendering and perceptually based tone mapping to generate a pictorial environment. Daylighting conditions were parametrically changed and psychophysical experiments were conducted to measure the perception of distance to visual targets within architectural scenes illuminated by various daylighting conditions. Results reveal that perceived distance to visual targets increases with a decrease in the luminance contrast between the target and background. This paper concludes that variations in luminance within a space influence perceptions of spatial depth, providing the possibility of enriching the experience of architectural scenes through the incorporation of daylighting in design strategies.
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  • Energy Efficient Lighting System Design for Hospitals Diagnostic and Treatment Room—A Case Study
    Safaa Alzubaidi, Prashant Kumar Soori
    Article type: Research note
    2012 Volume 36 Issue 1 Pages 23-31
    Published: April 01, 2012
    Released on J-STAGE: June 19, 2012
    DOIhttps://doi.org/10.2150/jlve.36.23
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    Lighting plays an important role in the Hospital Diagnostic and Treatment Room. It shall be environmentally and functionally suitable for three groups of people: patients, hospital professionals and visitors. On the other hand lighting is considered a major consumer of electrical energy and therefore, hospital lighting design should consider the visual performance, visual comfort and energy efficiency. This article discusses the performance of different types of lighting installations used for hospital lighting system design applications: first the visual comfort and second to save energy consumptions in such applications. DIALux 4.8 simulation software is used to study and evaluate the efficient lighting scheme for the hospitals through the use of different types of lamps. Also, visual environment lighting system design procedure is explained. Economics of different lighting scenarios are highlighted.
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Letter
  • BR30 Reflector Compact Fluorescent Lamp with Improved Run-up Performance
    Xiangfen Feng
    Article type: Letter
    2012 Volume 36 Issue 1 Pages 32-34
    Published: April 01, 2012
    Released on J-STAGE: June 19, 2012
    DOIhttps://doi.org/10.2150/jlve.36.32
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    The run up characteristics of BR30 reflector compact fluorescent lamps are investigated to optimize lamp design for performance improvements. The design is optimized based on the current reflector amalgam lamp, characterized in that the solid mercury is added into the discharge tube and the paraffin wax is put at the bottom of the reflector to connect the discharge tube and the reflector bottom together. The experimental results show that the run-up time can be shortened by about 20 s, the light efficacy can be increased by about 5 lm/W, and the bottom temperature of the discharge tube can be reduced by about 25°C by the optimized reflector lamp design.
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Errata
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