Journal of Light & Visual Environment

The cause of lamp voltage increase of high pressure sodium lamp

Akihiro INOUE, Tadatoshi HIGASHI, Toshihiko ISHIGAMI, Satoshi NAGANO, ...

1979 Volume 3 Issue 1 Pages 1_1-1_5
Published: 1979
Released on J-STAGE: June 07, 2011

DOIhttps://doi.org/10.2150/jlve.3.1_1

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During high pressure sodium lamp (HPS lamp) operation, are voltage increase. The cause of this phenomenon was investigated by the following methods. At first, the relation between the increase of the lamp voltage and the temperature of the coldest spot, at which excess amalgam condensed, was obtained using a liquid indium bath. It was found that the main cause of the lamp voltage increase was sodium loss and the quantity of the lost sodium in a lamp, which initially contained 7.5 mg sodium and of which lamp voltage increased from about 90 V to about 160 V during the life, was about 5 to 6 mg. Then, the quantity of lost sodium and the attacked position of an almina arc tube were investigated with neutronactivation analysis. It has become clear that lost sodium attacked the low temperature part of the alumina during operation.

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A new deluxe fluorescent lamp with a color rendering index of 99

Katsuo MURAKAMI, Jiro NARITA, Yoshinori ANZAI, Hiroshi ITOH, Sadaharu ...

1979 Volume 3 Issue 1 Pages 1_6-1_11
Published: 1979
Released on J-STAGE: June 07, 2011

DOIhttps://doi.org/10.2150/jlve.3.1_6

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Fluorescent lamps were studied to improve color rendering property without the use of filter to absorb blue-violet radiations. The general color rendering index (Ra) is possible to be raised effectively, when are controlled both blue-violet mercury lines and continuous radiations emitted from phosphors. A new strontium-borophosphate phosphor, with a chemical formula of [2 (Sr, Eu) O·0.84P₂O₅·0.16B₂O₃], was developed and its application in fluorescent lamp of accurate color rendition was examined. This phosphor absorbs not only ultra-violet radiation but also the visible blue radiation and emits bluish green light, having lower radiant power in blue-violet spectral region than usual antimony activated calcium halophosphate phosphor. The use of this phosphor is very effective to control the radiant power in blue-violet spectral region, and makes it possible to produce fluorescent lamps having Ra value of 99 and luminous efficacy of 60 lm/w, without the use of the filter for absorbing blue-violet radiations.

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Color eletroluminescence from ZnS thin films multi-doped with rare-earth ions.

Shoichi KURITA, Shinichi TAKAHASHI, Toshihiko SAKAGUCHI

1979 Volume 3 Issue 1 Pages 1_12-1_17
Published: 1979
Released on J-STAGE: June 07, 2011

DOIhttps://doi.org/10.2150/jlve.3.1_12

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The electroluminescence (EL) cell is made from thin films formed by the co-evaporation of ZnS and rare-earth metals. The radiation from this cell is caused by electron transitions between the levels of rare-earth ions. In this study we determine the relationship between the concentration of the rare-earth ions and the luminous spectral intensity in the EL cell and the applied voltage. The luminescence center of rare-earth ions in ZnS is localized center. If the ZnS is activated by two different rare-earth ions then the resultant emission color is the sum of two individual emission colors. Thus the emission color can be changed, as desired by controlling the concentrations of rare-earth ions. On the other hand it is observed that the spectrum of an EL cell containing several kinds of rare-earth ions changes when the applied voltage changes.

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Dual lamp operating circuit for high pressure mercury discharge lamps

Junichi YAMAGUCHI

1979 Volume 3 Issue 1 Pages 1_18-1_22
Published: 1979
Released on J-STAGE: June 07, 2011

DOIhttps://doi.org/10.2150/jlve.3.1_18

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The present research has been conducted with a view to energy saving and contemplates to use a single three-leg iron-core reactor in place of two core type iron core reactors used respectively in the capacitive and inductive ciruits of the conventional flickerless lighting device of the two-lamp or dual high pressure mercury lamp. It has become apparent from this research that, with the length l_a of the two air gaps between the central leg and the respective outer legs selected to be equal to 2mm, the capacitive and inductive circuit can be made substantially independent from each other and that, for the same voltages and currents in the various operating portions and the same mercury lamp power rating, the volume of the silicon steel plate and the iron loss can be reduced about 18% with the novel lighting device as compared to the conventional device.

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Study on the statistic estimation of the horizontal illuminance from unobstructed sky

Hiroshi NAKAMURA, Masato OKI

1979 Volume 3 Issue 1 Pages 1_23-1_31
Published: 1979
Released on J-STAGE: June 07, 2011

DOIhttps://doi.org/10.2150/jlve.3.1_23

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The standard value of the horizontal illuminace from unobstructed sky has not been yet established in Japan for the calculations of the daylighting and PSALI, though it is the most essential and fundamental for the energy conservation in the field of lighting design. A great deal of data on the horizontal illuminance from unobstructed sky have been gathered for several years by the authors when they tried to measure the luminance distribution of the sky under various conditions; the data cover not only almost whole seasons through a year and various times within a day, but also different meteorological conditions. Based upon those data, a proposal on the values of the horizontal illuminance from unobstructed sky at the selected standard point (35°N, 135°E) has been made by the statistical analysis and research investigations, following the values at Nagoya, related to the percentage of the available hours to many kinds of the designed working duration, such as 9 a.m. to 5 p.m. This proposal has been considered very reasonable and useful for the calculations of daylighting and its applications, so it has been extended to be applied in all over Japan. Furthermore the method developed by this research work and the results stated in this paper have convinced the authors of their world-wide applicability.

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Physical measurements of stray light in steer’s exscised eyeballs

Yoshikazu NAKANE

1979 Volume 3 Issue 1 Pages 1_32-1_41
Published: 1979
Released on J-STAGE: June 07, 2011

DOIhttps://doi.org/10.2150/jlve.3.1_32

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By using steer’s eyeballs, which are similar in optical characteristics to human eyeballs, the direct measurements of the amount of stray light in them have been made. The results are as follows:
(1) The effect of lapse of time after the steer’s eyeballs are taken out is negligible, if it is within 10 hours.
(2) The quantity of stray light grows greater as the light souce moves nearer to a point on the visual line, especially when the light source is within 10° (degree) of the visual point.
(3) The causes of the stray light are: (1) optical defects of eyes when the light source is within 10° of the visual point; (2) diffusion of light on the surface of the cornea when the angle stated in (1) is more than 10°.
(4) The smaller the iris grows, the smaller the quantity of stray light.
(5) When the light source is comparatively large, divide it into 1° units, and the total sum of the quantity of the units is almost equal to that of the quantity of the original light source.
(6) In order to obtain the ratio of E_θ to E_o, the following equations are used:
θ>1° E_θ/E_o=exp{(-l_nθ)³-0.25}+0.032θ^-1.8
θ≤1° E_θ/E_o=exp(-0.17θ)
E_o: Illuminance of fovea when the light source is on the visual line.
E_θ: Illuminance of fovea when the light source deviates by θ° from the visual line.

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Shadow characteristics under various light sources

—in the case of a horizontal disk as a shadow caster—

Yoshihiko OHTANI

1979 Volume 3 Issue 1 Pages 1_42-1_51
Published: 1979
Released on J-STAGE: June 07, 2011

DOIhttps://doi.org/10.2150/jlve.3.1_42

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This paper treats the research on the shadow characteristics under such conditions as both the light source and the shadow caster have various geometrical shapes. The shadow casting performance of a horizontal disk is described in several typical light sources—horizontal and vertical, each taking the shapes of a straight line, a rectangle, a square and a circle. A digital computer analysis shows specifications of the umbral, penumbral and ultraumbral regions on the illuminated plane. First, the methods for numerical calculation of the illuminance and the shadow factor within the shadow are explained briefly. Second, with a horizontal disk fixed as a shadow caster, the shadow characteristics of various light sources kept in several positions are shown. Third, those results are compared. Finally, the position and shape of the light source usefull to reduce as much shadow as possible are mentiond.

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Interreflection coefficients for interior lighting calculations based on CIE methods

Masayuki IIZUKA, Kozo ISHINO

1979 Volume 3 Issue 1 Pages 1_52-1_58
Published: 1979
Released on J-STAGE: June 07, 2011

DOIhttps://doi.org/10.2150/jlve.3.1_52

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The concept and practicability of two useful methods reported for interior lighting calculations in France have been widely introduced and discussed by a few Japanese investigators from various points of view CIE Publication No. 40: “Calculations for Interior Lighting —Basic Method—” was published in 1978, and the final report on “Applied Method” has now been prepared under the chairman of TC-1.5, A.B. de Graaff. The authors compare the computation process and its characteristics of RM and MR coefficients obtained by the present studies with that of these coefficients based on the CIE methods approved by TC-1.5, and point out the difference between the data of RM and MR coefficients prepared in the CIE methods and the numerical data calculated by the authors. Lastly, they discuss the effect on the final computation results for lighting designs from the standpoints such as room index, suspension ratio and effective reflectance of the ceiling cavity.

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Some error sources and their corrections in the measurement of relative spectral sensitivity by means of two—tandem—monochromator method

—on effective pass band and slit width correction—

Hideyuki MINATO, Motoi NANJO

1979 Volume 3 Issue 1 Pages 1_59-1_65
Published: 1979
Released on J-STAGE: June 07, 2011

DOIhttps://doi.org/10.2150/jlve.3.1_59

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The measurement of relative spectral sensitivity of detectors by two-tandem-monochromator method consists of two measuring steps; The measurement of spectral transmittance of a monochromator, and the determination of spectral sensitivity by the combination of the monochromator with the known spectral transmittance and the calibrated standard radiance lamp. This report discusses the two main factors which cause systematic errors in the second step. The one is the effective pass band which is an important quantity in order to estimate the flux which passes through the monochromator. An improved method to give the accurate dispersion curve and the effective pass band is described in detail. This method can exclude the errors which may be the amount of about ±5% in measuring the relative spectral sensitivity. The second one is the corrections to the errors caused by the finite slit width. An equation for the correction and the calculated results based on the measurement of the spectral sensitivity of some detectors are given. The errors are estimated more than 1% in the wavelength region longer than 600nm in case of S-11 type and less than 0.3% in almost whole wavelength region involved in case of S-20 type.

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