JOURNAL OF THE ILLUMINATING ENGINEERING INSTITUTE OF JAPAN
Online ISSN : 1349-838X
Print ISSN : 0019-2341
ISSN-L : 0019-2341
Volume 66, Issue 4
Displaying 1-8 of 8 articles from this issue
  • Modified Transfbrmation in the Contour Integration Method
    Sho Kamisaka
    1982 Volume 66 Issue 4 Pages 107-113
    Published: April 01, 1982
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    In a cubic model in which the illuminated point is directly under the origin of the co-ordinate axes located on a plane including a flat surface source thereon.
    Assuming the length of the intercept of the y axis defined by the tangent to the elementary curve of the boundary of surface source to be n, the length of the orthogonal projection of the elementary curve on the x axis to be dx, the distance between the elementary curve and the illuminated point to be l, and the distance between the origin and the illuminated point to be z, the formula E=L/2∫Sdω cosδin the contour integration method was analized, and as a result, the following relations were discovered.
    (1) In case the surface source is parallel to the illuminated plane,
    dω cosδ=n/l2dx,
    (2) In case the surface source is inclined to the illuminated plane,
    dω cosδ=n/l2dx cos β, and
    (3) In case the surface source is perpendicular to the illuminated plane,
    dω cosδ=z/l2dx
    Hence, the formulae for obtaining the element of illuminance by the part AB of the boundary of the uniform brightness surface source are as follows:
    for the case (1): E'=L/2ba n/l2 dx (1)
    for the case (2): (E')=L/2 cos β ba n/l2 dx (2)
    for the case (3): ((E'))=L/2zba 1/l2 dx(3)
    The routine method of obtaining the illuminance of a flat surface source by using these formulae is as follows:
    (1) obtaining y=f (x) and y' depending on the shape of the boundary of surface source.
    (2) obtaining the length of the intercept on the y axis by the formula n=y-yx.
    (3) obtaining l2.(in case of 1 and 3:=x2+y2+z2, in case of 2:=x2+y2+2yz sin β+z2)
    (4) substituting the above values into the above formulae (1) to (3).
    (5) setting the lower limit of the interval of the denite integral at the point where x is smaller.
    (6) calculating the elements of illuminance using Simpson's formula, etc.
    (7) obtaining the illuminance by subtracting the arithmetic sum of elements of illuminance belonging to the lower half of the boundary calculating from the arithmetic sum of the elements of illuminance which belongs to the upper half. In case the integral of parameter ψ or y is to be substituted depending upon the shape of the surface source, the procedure for such a substitution should be inserted between (5) and (6).
    The calculation of the illuminance of a fan-shaped source as shown in this paper is an example of a case where the integrals by x, y and ψ are mixed up.
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  • Yasushi Nakamura, Akihiro Nishito
    1982 Volume 66 Issue 4 Pages 114-120
    Published: April 01, 1982
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    A high speed spectrophotometer, employed silicon photodiodes array of 31 elementsand microprocessor, has been developed. This photometer can measure object-color in visible wavelength from 400 nm to 700 nm, at each 10 nm, in one second.
    High speed and accurate measurement of color is an essential needs for spectrophotometer, when applied to industrial use such as computer color matching.
    The contents of this paper are summarized as follow. Considering about noise of silicon photodiodes, linearity of detector current, and error in A/D converter system, total error of output signal from photodetector is less than 0.1% theoretically.
    Error caused by stray light, and error caused by deviation of central wavelength of each 31 detectors, can be corrected by data processing in microrrocessor.
    Comparing the measured results by ordinal spectrophotometer and by this high speed spectrophotometer, it has been shown that the accurcy of this spectrophotometer is good enough for industrial application.
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  • Toshiaki Mizuno, Taro Ishikawa
    1982 Volume 66 Issue 4 Pages 121-124
    Published: April 01, 1982
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    The metal halide lamp ballast of light weight and high efficacy is achieved by use of transistor chopper.
    The ballast can be divided into three units, a chopper circuit, a control unit and a rectification unit. The chopper circuit is composed of a high-power transistor, a silicon diode and an inductor of several mH. Main components of the control unit are an IC and a medium-power transistor. The IC has functions of a reference voltage generator, a clock pulse generator, an error amplifier and a pulse-width-modulator. And medium-power transistor amplifies the output of the IC to drive the high-power transistor. The rectification unit is consist of four sillicon diodes and a capacitor of several tens μF.
    When a discharge lamp is connecned to the chopper circuit, the lamp current tends to be increased rapidly or be extinguished because of the negative resistance or constant voltage characteristics of the lamp.
    Comparing the input current of chopper circuit with reference value, the control unit adjusts automatically the conducting time of the high-power transistor to stabilize the lamp current.
    In HID lamps, instability caused by accoustic resonance occurs at specific frequncy when h.f. current flows in a lamp. Therefore switching frequency of the chopper must be chosen to be apart from the frequency at which the instability occurs. In practice, a 100 watt metal halide lamp is operated by the ballast with switching frequency in the range of 13-18 kHz.
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  • Chihiro Masuda, Hideo Takahashi, Hidehito Takayama, Taketoshi Tsuda, S ...
    1982 Volume 66 Issue 4 Pages 125-130
    Published: April 01, 1982
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    The construction of a light source with variable wavelength utilizing a combination of an Acoustooptic tunable filter employing a TeO2 crystal and an incoherent white light source, of which the wavelength and intensity of the optical output is to be arbitrarily controlled, are described. As example of applications, an automatic measuring method for spectrometory are proposed.
    As a result, the following conclusions are obtained.
    (1) The optical output power of the apparatus depends on the wavelength characteristics of the feedback system.
    (2) The spectral reflectance characteristics can be measured automatically by using the combination of a light source with variable wavelength and a microcomputer.
    (3) The measurement time of the spectral reflectance characteristics is about 10 minutes.
    (4) The spectral sensitivity and the spectral transmittance characteristics were expressed on an oscilloscope as still picture of the periodic time T≅40ms.
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  • Applicability of High Pressure Sodium Lamps with High Color Rendering Indices to the Interior Lighting
    Takayoshi Fuchida, Yuji Danno, Jun-etsu Akiyama, Takashi Ichijo, Leo M ...
    1982 Volume 66 Issue 4 Pages 131-137
    Published: April 01, 1982
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    For checking the applicability of HID lamps, especially of high pressure sodium lamps (NH'') with general color rende-ring index 85, to the interior lighting, several lighting effects of these lamps are evaluated comparing with incandesent lamps mainly fromPYthe subjective point of view.
    Evaluated effects are environmental impressions of color and brightness, color rendering of actual complexions and color discrimination properties.
    Results are summarized as follows:
    (1) NH'' lamps are as preferable as incandescent lamps for the residential lighting. When overall impressions are included tin-halide lamps are more preferable than NH''
    (2) Subjective effects of HPS lamps with different properties on color rendering are properly evaluated by the CIE general color rendering index.
    (3) For lighting the interior space with highly chromatic objects, NH'' with the illuminance level of 1/1. 25 produces similar apparent brightness to incandescent lamps.
    (4) NH'' has better color discriminating ability than incandescent lamps but less than tin-halide lamps.
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  • Koichi Ikeda, Masaharu Nakayama, Kiyoshige Obara
    1982 Volume 66 Issue 4 Pages 138-143
    Published: April 01, 1982
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    Perceived colour-differences of colour chips are estimated subjectively by means of ratio estimation method under standard illuminant A and daylight D65, and are compared with their colorimetric ones in the CIE 1976 L*u*v*, the CIE 1976 L*u*v*, a modified L*u*v*, and a modified Cube-root colour spaces.
    The set of colour chips used in the experiment consists of one hundred and sixty hues with constant value and chroma of 6/8 in the Munsell renotation system. Colorimetric colour-differences of the pairs of colour chips are within the range of 0.89 to 17.56 under daylight illuminant D65 in the CIE 1976 L*a*b* uniform colour space.
    Results obtained are summarized as follows:
    (1) Relative values of perceived colour-differences change little even when the illuminant changes from D65 to A, and the constancy of perceived colour-difference holds as well as in the case of colour chips of lower chroma.
    (2) Under the daylight D65, the degrees of correlation between perceived colour-differences and colorimetric ones are little different among the colour spaces examined, but under the illminant A the degree in the CIE L*u*v* colour space is a little lower than the others.
    (3) The variation with hue angle of the ratio of colorimetric colour-differences under the illuminant A and those under the illuminant D65 in the CIE L*u*v* colour space is the largest, and that in the cube-root colour space is the smallest.
    (4) The correction to the chromatic adaptation in terms of colour-differences is well done in the cube-root colour space, and it is scarcely done in the CIE L*uv* colour space.
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  • Toshiro Kajiwara, Yoshinori Anzai
    1982 Volume 66 Issue 4 Pages 144-149
    Published: April 01, 1982
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    When the fluorescent lamp, which is filled with low pressure krypton gas and saturated mercury vapor, is operated on a commercial ballast working at domestic frequencies, it has the characteristics as follows; as the electric power of the lamp is reduced at room temperature, it can sustain the light emission characteristics as same level as the general one. But if the ambient temperature around the lamp is lower than the room temperature, the fluctuation of light emission appears below the critical temperature, and the light emission is reduced remarkably. To investigate these defective phenomena of the lamp, authors studied the properties of the discharge voltage-current, the fluctuation frequencies and the wavelength of moving striations which depend on the ambient temperature at the constant pressure of the filling gas. As the results, authors obtained conclusions as follows.
    (1) The fluctuation of light emission behaves like as the positive moving striations.
    (2) The temperature at which moving striations appear is determined by a mole fraction and a mole number of kryptonmercury vapor mixture in the discharge tube.
    (3) These moving striations show the similar characteristics to “r”wave which based on the fluctuation of ion density in Ne discharge.
    (4) In this temperature region in which moving striations appear, the excitation of krypton gas is activated, and the light emission of mercury line decreases.
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  • Tomoyuki Nishita, Eihachiro Nakamae
    1982 Volume 66 Issue 4 Pages 150-156
    Published: April 01, 1982
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    This paper proposes the following two techniques for lighting design; color-shaded perspectives of three dimensional objects, which are lighted up with several different types of light sources, andisolux diagrams, which are expressed by color belts consisting of different colors depending on illuminance levels, overlapped with the perspectives.
    The advanced points of this paper are as follows:
    Firstly, displaying perspectives observed from arbitrary viewpoints, designers can easily examine luminous intensity, color, and arrangement of light sources in order to search the optimal lighting effects ; that is, the designers can closely watch the whole or local viwes by moving their viewpoint and center of vision. Secondly, by overlapping an isolux diagram with color belts and the perspectives, the designers can easily grasp the illuminance distribution of every part.
    Futhermore, by picking an arbitrary part from the picture, extending it into the whole size, and subdividing each isolux belt, the designers can get more precise data.
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