Several mathematical models for discharge lamps have already been offered. However, all these models are only used for the operating state. There are not any models for the starting process.
This paper is concerned in the mathematical models for the starting process of discharge lamps. Newly introducing the concept of thermal quantity, the authors could have the mathematical model to represent the starting process of the low pressure sodium lamp.
In this paper, the following comparison between the theoretical results by this model and experimental results on the low pressure sodium lamp is discussed.
(1) The lamp voltage and current waveforms in the starting process
(2) The judgment whether the lamp can get to the operating state or not
These investigations showed that this model is available for representing the starting process of the low pressure sodium lamp.

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“Heatlite” (windshields with electric heatlines) has been designed to keep visual field clear through windshields especially in the cold climate area. Static and kinetic visual acuity, and accommodation time were examined before and after watching a movie through Heatlite and normal windshields, in order to investigate effects of Heatlite on visual functions.
No difference was observed between the two types of windshields in frequency of asthenopia or hinderance of vision.

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Photometric error due to non-uniform responsivity at the surface of a detector is theoretically analyzed for illuminance measurement and for light beam flux measurement by means of an illuminance meter. In illuminance measurement, photometric error is caused only when responsivity and illuminance are not distributed uniformly in the aperture of the illuminance meter. This error is given by the product of the relative standard deviations of both distributions and their correlation factor. As a result, the relative standard deviation is proposed as the parameter to describe the non-uniformity of each distribution. The spatial resolutions reequired to measure both distributions, which would make it possible to precisely estimate the above error, are also discussed. The conclusion is reached that, if the distribution of either responsivity or illuminance is more gradual than the other and sinusoidal, the resolution should be smaller than 1/8 the spatial period in which the sinusoilal patterns are repeated.

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It was discovered that rare earth halides of thulium, holmium and erbium, added in combination with thallium halide to the high pressure mercury discharge lamps, emit high color rendering white spectra with high efficacy, It was also discovered that the emissions from these lamps consist of the atomic line spectra of the metals and the molecular con-tinuous spectra of the rare earth halides. The atomic spectra of the rare earth metals are mainly in the short wavelength region of the visible range and the molecular spectra are in the long wavelength region around 600 nm. This characteristic is applicable to the dysprosium halide additive lamp.
Metal halide lamps with thulium, holmium or erbium emit excellent spectra especially when operated at high wall load around 20 W/cm² so as to attain the high vapor pressure of the rare earth halides. For example, the thallium-thulium iodide additive 400 W high wall loading lamp, of which the arc length is 28 mm and the tube diameter is 18 mm, has a luminous efficacy of 105 lm/W and the genearl color rendering index R_a of 75, while the thallium-holmium iodide additive lamp has a luminous efficacy of 90 lm/W and the index R_a of more than 90.

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At precise spectral sensitivity measurement of the detectors, the recieving surface must be uniformly irrdiated. However, the usaul monochormator exit irradiance distribution is irregular and vary from wavelength setting.
The optical fiber bundle, which is set between exit slit and detector, improve to the irradiance uniformity with a small radiant flux loss. The bundles are constructed 8000 to 100glass or plastic fiber of 0.03 to 0.25mm diameter and guide lenghth of 100 to 300mm.
The results from combination of bundle and monochromator (with light source) are as follows:
(1) On wavelength region of 390 to 720nm, the bundle exit radiation uniformity is not varied,
(2) Radiant flux over the 90% uniformity ratio area is about 0.2 times of bundle total emitted flux.
(3) With NIKON G-250 monochromator and 150 W halogen lamp, bundle out put power over 90% uniformity ratio area is 2.5 to 9μW at 390 to 760nm.

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This research relates to the energy saving on a line connected with non-liner type load. First, Fourier analysis is applied to the harmonic voltage and current waveforms of each element on the lead type operating cir cuit for the high pressure mercury arc lamp. Referring to the result, a theoretical analysis is applied to obtain the harmonic power of each element on the operating circuit. Then, an experiment is conducted. As a result, the following conclusion is obtained:
(1) It is revealed that, the formerly reported lag type operating circuit similarly, distorted wave power e. g. 3rd or 5th harmonics, etc. are continuously exchanged between mercury arc lamp and capacitive ballast.
(2) Based on the voltage and current characteristics of the choke coil, it is made obvious how to determine the capacitance (μF) in the lead type operating circuit.
(3) Load share (vA) between choke coil and capacitor is theoretically determined in case that a high pre ssure mercury arc lamp (H100) is operated on a lead type ballast. As a result it is revealed that. there is a limit corresponding to the value of α=X_L/X_c. Where X_L and X_c are fundamental reactances, respectively, of the choke coil and capacitor.

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Recently, from a standpoint of view of energy-saving, a new daylighting system using ducts, by which outdoor daylight can be conveyed to the back room in a house, has been becoming a subj ect of our attention. In this paper, a new formula, by which the efficiency of daylighting through a optional rectangular duct can be estimated, is introduced basing on a theory as to specular reflection.
This formula includes three peculiar factors to any duct, namely, size of section, length of a duct, and the reflectance of inside surface. Feeding this formula into a computer, the daylighting efficiencies as to various combinations of these three factors are calculated, and, as a result, the relation between the efficiency and each factor is made clear.
Furthermore, some model experiments having several sectional areas and scales are carried out, and their results show that the measured value of daylighting efficiency on every model is consistent in a reliability of 95% with each computeraided value based on this proposed formula.

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Measuring principles and general construction of a high-speed fully automatic gonio-photometer for measurments of photometric performance of luminaires are described.
The gonio-photometer consists of 58 independent photoreceptors arranged on a steel frame, constructed in such a way that the center of the photoreceptors is on a vertical plane which passes through the optical center of the luminaire to be measured, and that the direction of maximum photo-electrical sensitivity of the photoreceptors is also aimed at the optical center.
The steel frame consists of five members: two horizontals, one on the floor, another on the ceiling, one vertical on the wall, two inclined at an angle of 45 degrees to connect the horizontals and the vertical; the minimum distance between the photoreceptors and the optical center is 4. 5 meters. The luminaire to be measured is fixed on a horizontal arm which can be turned around the vertical axis by means of a pulse motor mechanism.
The entire measuring sequence and data processing is controlled by an integrated 16 bit micro-computor.
With the gonio-photometer, measurements of the complete indicators of photometric performance of a luminaire can be finished within two minutes. Subsequent data processing to derive total flux output, zonal flux output, output ratio, together with the angular distributions of luminous intensity, can be calculated within one minute.

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This paper discribes a new method to change luminons color of a positive column ofa low pressure Hg-Ne discharge lamp.
Pulses of triangle wave form, whose width, rise time and recurrence frequency had been changed widely, mere applied to discharge lamps of 10 cm in interelectrode distance and from 1 cm to 5 cm in diameter.
The color of the positive column could be controlled electronically from blue to red by varying pulse rise time only, heving kept pulse voltage, pulse width and pulse recurrence frequency constant.
In general, when the pulse rise time is shorter than 10 μs, the color is red and, on the contrary, it is blue when the rise time is longer than 150 μs.
The optimun recurrence frequency, at which the change of color from red to blue and vice versa is favorable by varying only the pulse rise time, has such a relation with diameter of discharge lamp that f =210/ (2R) Hz and is insensitive to change of the pulse width.

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Lighting design is to be founded on visual evaluation of luminous environment. About the evaluation method, it is pointed out that the method customary used today has no regard for the actual condition of the worker's eye in the room. His sight line is not always fixed to the visual object, nor his eye always perfectly adapted to the luminance of his visual fi eld. In order to make clear the real visual sensation, it is necessary to take the movement of sight line into the lighting evaluation.
This paper is the first step of our dynamic evaluation study, and contains followings:
(1) Investigation to the actual movement of worker's sight line in the lecture room.
(2) Results of measurement of dark adaption time to clarify the process of adaptation.
(3) A brief example of dynamic evaluation based on the results above taken.

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The three-band-type fluorescent lamp (3-Band) has a unique spectral power distribution which has been optimized to increase both the general color rendering index (CRI) and the lamp efficacy and it is sometimes said that the lamp has some particular effects more than estimated from the CRI and the efficacy. These effects of the lamp has been examined from various view points in compariosn with other commercial lamps.
Colorimetric calculations show that the 3-Band illumination is not suitable for color discrimination problem though it has practicall no problem, in the color perception of surface colors in the usual environment. The 3-Band has good performance in the color rendition for human complexion, and it becomes more preferred in some aspects under the 3-Band added with the halophosphate phosphor than that of the pure type. The 3-Band has unique effects on the brightness and the visual clarity of illumination compared with the other lamps of not only standard types of cool white and daylight color lamps but also de-luxe lamps which have a higher CRI with the broad band continuous spectral distribution.
The authors propose a new numerical expression to distinguish the 3-Band from the other types of lamp. That is the ratio of the power in the three spectral regions (445-475, 525-555, 595-625 nm) to the total power (400-700 nm).

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Based on the “Fundamental Studies on Lighing for Better Seeing” which I have conducted previously, I have examined the method of designing on the task lighting environment of better quality from the viewpoint of better seeing of visual objects.
As a result, it is revealed that the qualitative improvement of lighting for better seeing can be realized by the following method.
(1) The basis will be the standard visual acuity curves (Fig.5).
(2) When background luminance is not uniform, it will be adjusted to achieve the same visual easiness as in the case where uniform background luminance exists (Fig.7).
(3) The influence of high-luminance light source to the visual perception threshold will be expressed on the standard visual acuity curves as changes in background luminance and contrast (Fig. 6).
(4) Letters will be replaced with Landolt's Ring visual targets which have equal visual perception thresholds (Fig.4).
(5) The standard visual evaluation chart will be used for the evaluation of the lighting designed room.
(6) The background luminance and contrast of the visual object in the visual work position will be determined (Fig.3)
(7) On the standard visual acuity curve, the background luminance will be determined at which the visual object reach the visual perception threshold. The readability evaluation value can then be obtained on the equation (5).

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This paper describes the effect of xenon gas on the high pressure sodium arc. The previous paper reported that with increasing xenon gas pressure, the spectral broadening of the D-lines increased. In this report, the arc temperature profiles of 20 Torr filling gas pressure and 300 Torr filling gas pressure of the HPS lamps were measured and the following profiles were estimated:
Xe 20 Torr: T=4120-(4120-1370)(r/R) ^2.3
Xe 300 Torr: T=4280-(4280-1320)(r/R) ^1.6
Using these profiles, the spectral distributions were calculated by the radiation transfer equation and the calculated results showed the spectral broadening of the D-lines of the Xe 300 Torr arc was a little greater than that of Xe 20 Torr. From this result, it is considered that with increasing xenon pressure, the arc “shrinks” and the thickness of the dark annular space increases so that the broadening of the spectral lines increases.

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The accuracy of CIE proposed one monochromator method was studied on the basis of the two monochromator method regarding the Colorimetry of fluorescent materials. In all the experiments, the fluorescent materials were always illuminated normally and viewed at 45° from the normal.
The results studied are summarized as follows:
(1) A theoretical account is given to estimate the accuracy of the CIE proposed method on the basis of the measurement by use of the two-monochromator method. The accuracy is discussed on the total, the reflected, and the fluorescent spectral radiance factor (SRF), respectively.
(2) It is confirmed that the CIE proposed method is able to give the total SRF's of fluorescent materials under D₆₅ within an average deviation of 1 % from those measured and estimated by the two-monochromator method. This average deviation of the total SRF's corresponds to the color difference less than 1 CIE LUV unit. In the overlapping region by excitation and luminescence, however, the deviation of the reflected SRF shows an error from 2 to 4 % in some fluorescent materials, and the error of Q (μ) function (fluorescence radiant efficiency) is also significant.
(3) A simplified procedure is given for estimating Q (μ) function without using the spectral characteristic of the light receiver to be used. This simplification in the CIE proposed method is used provided that the colorimetric accuracy is allowed within the color difference of 1.5 CIE LUV unit.

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In the Hokuriku District, schoolrooms which get less sunshine often cause students to become shortsighted.
As a means of prevention from the eye trouble, our group has developed a new system to automatically adjust a lighting level in a school. We also believe that it will help save energy as well.
The system measures and responds to the lighting level on the desks serving an adequate lighting for the students.
This paper describes the experimental results and features-of its mechanism.

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In order to design a lighting equipment for the purpose of making the environment with high-quality illumination based on the standard visual acuity curves indicating the relationship among the minimum perceptible size of a visual object, luminance contrast and background luminance, the relationship between the Landolt's Ring visual targets and printed letters in visibility, and the relationship between the evaluated legibility and background luminance, it is necessary to know the luminance contrast of the object of visual task (e.g. books) and the luminance to which the eyes may accommodate themselves.
On the surface of a printed sheet, especially on the smooth surface of paper, the specular reflection component on the surface of paper may be increased depending on the relation between the direction of incidental hght and that of the visual line thereby decreasing the luminance contrast between the surface of paper and its lettered portion, thereby making the letters hard to read.
Therefore, a device as shown in Fig 1 was made in which t he incidental angle and incidental azimuth angle of the light over the surface of specimen could freely be changed and the luminance of reflected light was measured on each blank sheet of coated paper, high-grade paper medium-grade paper, rough paper, indian paper, hit-copy paper, G roll paper, and art paper frequently used in making printed matters in general, as well as on each sheet printed in black. The result is summarized as follows:
(1) The reflection characteristics of those Papers markedly varies depending on the kind of paper, and even if the quality is just the same, the characteristic may be widely varied depending on the position of the light source (incidental angle θ_i, azimuth angle ψ) Furthermore, the influence of the position of the light source (θ_i, ψ) to the value of reflection characteristic is varied depending on the quality of paper (Figs. 3-10)
(2) The above-mentioned remark made in paragraph 1 concerning the value of reflection characteristic can be applied to the reflection characteristic of the black-printed sheets, or to the ratio of reflection characteristic value of the blank parts to that of black-printed parts, or, accordingly, to the luminance contrast of visual objects.
(3) The coated paper has a relatively small change in the contrast of the visual object caused by θ_i, and ψ, whereas the art paper and G roll paper have remarkable changes in contrast caused by the position of the light source (θi, ψ). because of the intense specular reflection component (Figs. 11-12)
(4) Art paper and G roll paper have a luminance contrast markedly reduced when the light source is in the direction of the regular reflection, but if the position of the light source is slightly deviated from the direction of the regular reflection, the contrast is remarkably raised (Figs 11-12).
(5) The luminance contrast on the rough paper is not much raised no matter in which direction the light source is posi tioned.

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