JOURNAL OF THE ILLUMINATING ENGINEERING INSTITUTE OF JAPAN
Online ISSN : 1349-838X
Print ISSN : 0019-2341
ISSN-L : 0019-2341
Volume 104 , Issue Special
Showing 1-2 articles out of 2 articles from the selected issue
  • Shuilan He, Yuki Nakajima, Takayoshi Fuchida
    2020 Volume 104 Issue Special Pages 3-10
    Published: November 01, 2020
    Released: October 30, 2020
    [Advance publication] Released: April 17, 2020
    JOURNALS FREE ACCESS

    We previously revealed that the appearance of the color of glossy fabric and the effect of saturation and colorfulness on the texture impression are significant. In this study, we examined the color appearance of fabrics with various surface characteristics and the effect of illumination and spectral distribution on texture impression. We first evaluated the color appearance and texture impression of the fabric with various surface characteristics under different illuminance levels. We then evaluated the color appearance and texture impression of fabric under illumination by changing color rendering by spectral distribution. The evaluation of the color appearance of the fabric was more likely determined only by color saturation and colorfulness than the difference in the surface characteristics of the fabric. The texture impression of the fabric was also affected by the difference in the surface characteristics of the fabric (especially with or without specular reflection) in addition to the differences in saturation and colorfulness. Under lower illuminance, the fabric tended to be evaluated as smooth because the visual-acuity reduction due to the low illuminance under dim light reduced the ability of the observer to recognize the fabric surface structure. It is thought that this affected the evaluation of texture impression.

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  • Yuki Kamiya, Yoshinori Komatsu, Emi Kaga
    2020 Volume 104 Issue Special Pages 11-17
    Published: November 01, 2020
    Released: October 30, 2020
    [Advance publication] Released: July 31, 2020
    JOURNALS FREE ACCESS

    In standard white LED, the spectral distribution in the short wavelength region of visible light is most prominent. On the other hand, the newly developed sunlight type LED has a flat spectral distribution in the short wavelength range. This property improves color rendering and suppresses eye fatigue caused by blue light. The purpose of this research is to investigate the effect of these benefits on productivity.

    Ten subjects were asked to solve calculation problems for two hours under standard white LED and sunlight type LED. The results of the calculation problems, physiological changes, and questionnaire responses were evaluated. Under the sunlight type LED, the subjects were more focused and solved more problems than when exposed to standard LED. Moreover, under the sunlight type LED, changes in facial skin temperature and the standard deviation of the blink strength were minimal, and mental fatigue was suppressed. The results indicate that sunlight type LED improves concentration, suppresses eye fatigue and mental fatigue, and increases productivity.

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