JOURNAL OF THE ILLUMINATING ENGINEERING INSTITUTE OF JAPAN
Online ISSN : 1349-838X
Print ISSN : 0019-2341
ISSN-L : 0019-2341
Volume 82, Issue 8
Displaying 1-10 of 10 articles from this issue
  • Akiko Negishi, Takeshi Nishimura
    1998 Volume 82 Issue 8 Pages 513-522
    Published: August 01, 1998
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    On a CRT, we can see two modes of color appearance: illuminant mode and surface mode. These interchange as the luminance of the stimulus itself and its background changes. We investigated the relationship between the mode appearance and the luminance, and presented an equation expressing the illuminant mode appearance function of stimulus luminance and background luminance. The appearances of these modes are rated using the rating scale method.
    For constant background luminance, the appearance of illuminant mode increases linearly with increasing logarithmic stimulus luminance. The higher the background luminance is, the lower the luminance ratio needed to perceive the same degree of illuminant mode. For constant stimulus luminance, the appearance of illuminant mode decreases slowly when the background luminance is sufficiently low. But after the luminance ratio has dropped to a certain level with the background luminance increasing, the illuminant mode disappears rapidly.
    According to the obtained equation, the scores of illuminant mode appearance are directly proportional to the logarithmic luminance ratio, and its coefficient is linear with respect to the background luminance.
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  • Haelim Yoon, Taiichiro Ishida, Mitsuo Ikeda
    1998 Volume 82 Issue 8 Pages 523-529
    Published: August 01, 1998
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    A series of our previous studies showed that we can experience a sense of continuity between two physically separated spaces by adjusting the illumination in them.
    In the present paper we measured the illuminance and color of the illumination that provided a sense of continuity between two rooms connected by a window. In the experiment the illuminance and illumination color of the observer's room were changed while those of the other room were kept constant. The results showed the tolerable range of illuminance was almost constant despite changes in color difference: it amounted to 301x. Also the sense of continuity could be achieved within ±0.035 of the difference of x chromaticity coordinates of the illumination in the two rooms. We think that these two factors affect continuity perception independently. The results obtained here are applicable to lighting system design to provide a sense of continuity.
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  • Chiho Satoh
    1998 Volume 82 Issue 8 Pages 530-537
    Published: August 01, 1998
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    It has been reported that color perception of bluish lights changes with age because of a considerable decrease of the sensitivity in short-wavelength region caused by the yellowing of the crystalline lens. However there is an opinion that the color perception of aged-people is compensated by chromatic adaptation since the yellowing of the crystalline lens gradually grows across the life-span.
    In order to clarify the change in color perception caused by aging, I conducted two experiments. First, the 100-hue test of the Japan Color Research Institute was performed to 70 observers aged from 20s to 70s. Second, an experiment of color naming to 16 color samples using Natural Color System was done to 200 observers aged from 10s to 50s.
    As a result of the 100-hue test, the age-related decline of color discrimination properties to the reddish-purple colors was admitted whereas color discrimination properties to the bluish colors did not dropped. On the other hand, the experiment of color naming showed that there was no age-related change of color perception.
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  • Mitsuru Oikawa, Masao Ohtsuka, Takayuki Uchida, Masami Satou, Yoshiyuk ...
    1998 Volume 82 Issue 8 Pages 538-543
    Published: August 01, 1998
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    To clarify more physically the quality of visual sensation known as complementary color after image, we compared the change in CFF values under complementary color after image and under same color ofthe real light given as surrounding light. The tendencies of both changes were roughly as follows:
    (a) when the color of flickering light and complementary color after image and also surrounding light were similar, the values of CFF decreased monotonically with increasing brightness of complementary color after image and surrounding light.
    (b) when the color of flickering light and complementary color after image and also surrounding light were complementary the values of CFF increased in the higher brightness range of complementary color after image and surrounding light. Therefore we conclude that the effects of changing CFF values are controlled by the “color adaptation mechanisms” not only in the case of real surrounding light but also that of perceptual quantity ofcomplementary color after image.
    Moreover by applying Ferry-Porter's law to result (a), we were able to roughly estimate the effects of changing CFFvalues due to the perceptual quantity of complementary color after image by the effects due to physically measurablequantities such as flickering frequency and light brightness.
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  • Tetsuo Kadonaga, Shinichi Kohsaka, Hitoshi Yanagihara
    1998 Volume 82 Issue 8 Pages 544-550
    Published: August 01, 1998
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    Japan does not receive enough solar energy to grow figs. By comparing the received solar energy of major fig producing areas of the world and Japan, we have derived the supplemental light energy value, which is the minimum additional light energy necessary for optimal fig maturation. By supplementing natural sunlight with this optimum value by electrical lighting, the fig season in Japan can be lengthened, crop volume increased, and fruit quality improved.
    The optimum period for fig maturation in Nagoya is from June to September, when the minimum temperature remains above 20°Cin Nagoya, Athens, Izmir, and San Diego. During this same period, however, Athens receives direct sunlight for approximately 1, 308 hours, while Nagoya gets approximately 638 hours, i. e. about 49% of Athens. These four months also provide average estimated solar energy levels of 17.5 MJ·m-2·days-1 for Athens, 15.3 MJ·m-2·days-1 for San Diego, and 8.8 MJ·m-2·day-1 for Nagoya. A normal cultivation environment from January to March in winter will require additional supplemental light energy 5.1 MJ·m-2·day-1 which is derived from the difference in the solar energy between 8.8 MJ·m-2·day-1 for outdoor maturation in Nagoya and 3.7 MJ·m-2·day-1 for a green house in winter.
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  • Eiichiro Toriumi, Sosuke Morii, Miyosi Ayama, Takeshi Kumagai
    1998 Volume 82 Issue 8 Pages 551-563
    Published: August 01, 1998
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    Although a number of studies have been reported on the distribution of the B/L ratio in the chromaticity diagram, most of the results were measured with a simple achromatic surround condition. In real life we encounter a variety of visual environments that contain many colors of different luminances. Thus we measured the distribution of the B/L ratio in the chromaticity diagram under five different surround conditions: one was a dark condition comparable with those in previous studies, and the others were pictures of real scenes such as daytime residential, daytime downtown, nighttime downtown, and nighttime residential areas. The results obtained under the nighttime residential surround showed good agreement with the results of the dark surround, whereas the results of the other three surround conditions showed some deviations from the dark surround results. The average deviation of the B/L ratio from the dark surround results increased as a function of the average luminance of the surround. This suggests that the average luminance of the scenery surround is an important factor in determining the B/L ratio.
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  • Katsunori Okajima, Michiko Iwata
    1998 Volume 82 Issue 8 Pages 564-572
    Published: August 01, 1998
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    We derived ocular spectral transmittances as a function of age with aging models of the human lens and calculated the age-related change in retinal illuminance of D65, D50, and A-lights. The results show that the retinal illuminance of A-light for a 70-year-old person decreases to approximately 0.75 times that for a 22-year-old, and that the magnification factor in the case of D65-light is as low as 0.72. In addition, we conducted an experiment to measure the optimal illuminance for reading a newspaper under two kinds of fluorescent lamp condition (daylight and incandescence colors) for young and aged subjects. The results indicate that aged subjects needed higher illuminance for the reading task than young subjects. We demonstrate that the analysis with aging models of the human lens can explain the tendency of the difference between young and aged subjects in the experimental results. We believe that our approach in the present study will be useful for making a practical standard concerning comfortable illumination environment for aged people.
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  • Takayuki Hisamune, Shigeo Fujino, Yasuo Oguri, Tadashi Endo
    1998 Volume 82 Issue 8 Pages 573-579
    Published: August 01, 1998
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    Various compositions of Ba1-α-βSrαEuβMgl1-γ MnγAl10 O17 (BAM) phosphors were prepared. Their emission spectra and the dependence of efficiency on temperature under 254nm excitation were studied. The more α and/or/β values, the longer the emission wavelength of Eu2+ and the lower the efficiency at high temperature. A configurational coordinate model shows that these changes are due to a shortening of the Eu2+-02- distance in the phosphor crystal. Furthermore, tricolor fluorescent lamps, which use one of these phosphors as the blue component, were simulated. It was calculated that, by increasing α or β from the conventional values of α=0, β=0.1 and γ=0.02, Ra can be increased without a reduction in luminous flux. The higher the color temperature of the lamp, the more its Ra and luminous flux depend on the composition of BAM. The maximum Ra achieved by changing the composition of BAM in each color temperature increases with an increase in the color temperature, while the luminous flux decreases. Ra = 90 is predicted for a lamp in which the phosphor layer consists of a mixture of only three kinds of phosphors: BAM with α=0.3, β=0.1 and γ=0.015, Y203: Eu and LaPO4: Ce, Tb. Two kinds of lamps were prepared and tested, and the simulation results were confirmed.
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  • Akira Uchida, Yoshihiko Ohtani
    1998 Volume 82 Issue 8 Pages 580-587
    Published: August 01, 1998
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    Shadow is something we experience in our daily lives and a significant obstacle to our work. So shadow has been considered one of the important factors in lighting design.
    In this paper, the illuminance distributions on a desk as the working plane when Task Ambient Lighting, which is one type of office lighting systems, and a globe as a shadow caster are set up in a model room containing fixtures are obtainedby the Monte Carlo method and the characteristics of the shadow are examined.
    First, in order to carry out the illuminance calculation by the Monte Carlo method in the case of a light source with a non-uniform diffuse distribution, the relationship between the cumulative luminous flux and uniform random numbers was found by the use of division mensuration.
    Next, some experiments were made under the same conditions as the calculations. Comparing the experimental results with the calculated results, difference between them, confirms that the above method is suitable.
    Then, we obtained and examined the shadow characteristics on the surface of the desk when the position of the shadow caster was changed.
    As a result, we found that Task Ambient Light makes a weaker shadow than one of Task light or Ambient light, and variations in the shadow area by Task Ambient Light are similar to those by Task light.
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  • Kazuaki Ohkubo, Motomi Horiuchi, Yasuo Nakagawa, Hitoshi Tozawa, Kenji ...
    1998 Volume 82 Issue 8 Pages 588-592
    Published: August 01, 1998
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    An intercomparison of relative spectral responsivity measurements of illuminance meters was carried out among five companies-TOPCON, HIOKI, Minolta Co., Ltd., Yokogawa M&C Corp. and Matushita Electric Industrial Co., Ltd.
    The spectral responsivity of the illuminance meters were measured by each company's spectral responsivity measurement system calibrated to each company's standard. As a result, the measured values of fs (fs is error definition of relative spectral responsivity recommended by Japanese Industrial Standard JIS-C-1609) were different within 1.7. The fs is identical with f1' recommended by CIE.
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