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J. of IEIJ Vol.85, No.11

The Abstracts of the Papers
J.Illum. Engng. Inst. Jpn. Vol. 85, 2001

No. 2 February
No. 5 May
No. 8A August
No. 11 November

No. 11 November
Experimental Study of Effects of Artificial Light Sources on the Coloring of Fig Fruits
Translucence Phenomenon of the Arc Tube for Inductively Coupled Electrodeless Metal Halide Lamps
A Method for Estimating Coloring Reproducibility in the Test Samples by Computer Color Matching
Variations in Illuminance Caused by Shadow under Task Ambient Lighting -- Considering the Arrangement and Luminous Flux of Ambient Light--
Restraint of Discomfort Glare by Linear Light Source

Experimental Study of Effects of ArtificialLight Sources on the Coloring of Fig Fruits
Tetsuo KADONAGA, Shinichi KOHSAKA and Hitoshi YANAGIHARA

 In the green house cultivation to diversify harvest times, supplemental lighting systems are necessary to compensate the lack of sun light. Besides, artificial light sources of the system for fig fruits are needed to accelerate the coloring.
 Paying attention that matured figs have reddish violet colors in general, using harvested figs, colors and quantities of pigments (anthocyanin) on their surfaces are investigated. On cultivating processes, figs are radiated by artificial light sources with different spectral distributions.
 By studying comparisons between spectral distribution of light sources and experimental results, it is confirmed that generations of pelargonidin and cyanidin in anthocyanin are related to the coloring, and that two types of fluorescent lamps are effective to generate pigments on surfaces of figs. One type is for use of coping machine, and the other is with three-band phosphors.

KEYWORD:green house, artificial light, spectral distribution, fig fruits, coloring, anthocyanin


Translucence Phenomenon of the Arc Tube for InductivelyCoupled Electrodeless Metal Halide Lamps
Kozo UEMURA and Toshihiko ISHIGAMI

The translucence phenomenon of arc tubes for inductively coupled electrodeless metal halide lamps was evaluated and analyzed, methods for decreasing the translucence were investigated.
 The surface of the fused silica was found to be etched in the hot region, and the fused silica was deposited on the cold-region surface. The change in translucence occurred as a result of this SiO2 transport phenomenon.
 Effects of the lamp parameters were evaluated. The translucence phenomenon is promoted under the condition that the dose material contained rare-earth metal halides.
 Another study showed that the partial pressures of free metal atoms around the wall of the arc tube (the pressures were controlled by adjusting the filled Xe pressure and added SnI2 amount) strikingly affect the translucence level.
The effects of the temperature of the arc tube and the effects of the electric field created by the induction coil were found to be not so great as the effects of the lamp fills and the partial pressures of the free atoms.
 OH radicals in the fused silica, which may promote the translucence change of the fused silica, were found to invade the outer and inner surfaces of the arc tube wall due to the use of an H2 - O2 burner in the bulb-forming process.
 Removal of these OH radicals with hydrofluoric-acid surface-etching treatment strikingly decreased the translucence change level.
 Therefore, removing the OH radicals from the inner surface of the arc tube is an important and basic condition for decreasing the translucence level of arc tubes.
 In arc tubes without an outer bulb, OH radicals that originate in H2O vapor in air invade the arc tubes. Calculation of distributions of OH radicals showed that after 20,000 hours of operation of arc tubes with 1mm thickness OH radicals reach the inner wall and the arc tube becomes translucent.
 This calculated result agreed well with the results of life-time testing.

KEYWORD:translucence phenomenon. SiO2 transport, rare-earth metal halide, free metal atom, OH radical


A Method for Estimating Coloring Reproducibility in the Test Samplesby Computer Color Matching
Kazuo SANO and Hiromitsu ISHII

 The colors of industrial products such as cars, houses, and fabrics are determined by a color matching process. Color matching is a process in which colorants and their ratios should be determined. There are two methods for color matching, that is a visual color matching method and a CCM (computer color matching) method which is now used quite frequently. CCM can reduce the color difference. However, color correction must be repeated if there is poor color matching due to the limitations in color reproducibility. In color reproducibility invesigation, the same samples with the same colorant ratios must be maked several times. However, it is difficult to make several samples in the color matching process. We used reflectance simulation in CCM to obtain reproducibility in samples with different colorant ratios in color matching.

KEYWORD:CCM, computer color matching, coloring, reproducibility


Variations in Illuminance Caused by Shadow under Task Ambient Lighting?\Considering the Arrangement and Luminous Flux of Ambient Light?\
Akira UCHIDA?CNaoki MATSUMOTO and Yoshihiko OHTANI

 We examined the characteristics of shadows created by task ambient lighting mounted on a ceiling on a work surface (a desk) for various combinations of lighting arrangements and luminous fluxes. Shadowing in work areas has become of greater concern with the decrease in illuminance on work surfaces due to the obstructions created by modern office designs (e.g., room partitions).
 We found that when the arrangement and flux produce an illuminance uniformity ratio of greater than 0.7, the maximum shadow factor is less than 0.6, and the areas in shadow are less than 15% of the total area. Application of this principle will enable the design of more comfortable and efficient offices.

KEYWORD:Task Ambient Lighting, Monte Carlo method, illuminance calculation, shadow