HID lamps have the high luminous efficacy of radiation and therefore, the ballast is desirable to be compact, light weight and energy saving type for illumination of the general use with line source. In addition, the continuous dimming also will meet a demand of suitable illumination, and then promote the spread of indoor use of HID lamps. This paper describes experimental results on high frequency operation from 60 Hz line source and its dimming control of HID lamps with frequency beyond 100 kHz with MOS-FET avoiding the acoustic resonance phenomenon. The system has demonstrated the characteristics of high power factor, stable performance, good controllability and the capability of continuous dimming control over the range from 100 to about 30 percent, although the overall efficiency is a little worse than that of a conventional type (core-coil) ballast because of wide dimming design.

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A new advanced system of daylight prediction has been developed and presented by the authors for the highest utilization of natural daylight and appropriate saving of the electrical power consumed by the artificial lighting in daytime. Though the research works for this system and for the Mean Sky upon which it is based have already been published^4)∼11), one of the most essential parts of the research work, that is, the framing of the Intermediate Sky and its detailed contents have been only presented in a brief paper in Japanese.⁸⁾ The Intermediate Sky was framed mainly from the current materials which had already been gathered by the authors before starting of the research work, as the measurement to be required for the establishment of the Intermediate Sky should be carried out for a very long time. The procedure of framing the Intermediate Sky and its results are stated in this paper.

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My preceding paper disclosed a simple method for calculating the illuminance of a flat surface source of arbitrary shape which could be expressed by x and y using the following new formulae:
(1) When the surface source is parallel to the illuminated plane:
E'=L/2∫^b_a(intercept on y axis)/(x²+y²+z²)dx
(2) When the surface source is inclined to the illuminated plane by ∠β:
(E')=L/2 cosβ∫^b_a(intercept on y axis)/(x²+y²+2yz sin β+z²)dx
(3) When the surface source is perpendicular to the illuminated plane:
((E'))=-L/2z∫^ba1/(x²+y²+z²)dx
where E'=the illuminance component for the interval A to B on the boundary of the flat surface source, L=luminance of the source, z=the distance from the illuminated point to the origin located just above the illuminated point for cases (1) and (2), and the distance from the origin to the illuminated point located on the normal to the origin for case (3). This note provides some calculation examples to find the illuminance of flat surface sources of various shapes by means of this new method, and discusses the case having the primitive function F(x).

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With a view to developing a new photometric system which will give a better agreement with the visual impression of the light, the effects of both the visual field sizes and the criteria for measurement of spectral luminous efficiency functions on the shapes of the functions were examined in the case of 2° and 10° fields, by applying two different methods, flicker photometry and direct heterochromatic brightness matching, using the same white reference. A 2° field function by flicker photometry was very similar to Judd’s modified V(λ) function while a 2° field function by direct heterochromatic brightness matching showed hilly humps on both sides of 570 nm. A 10° field function by flicker photometry showed no significant differences from both the CIE y₁₀(λ) and the ETL y₁₀(λ) functions derived from the color matching functions. These findings suggest that the CIE y₁₀(λ) function should be used as a standard photometric observer in the large visual field. A 10° field function by direct heterochromatic brightness matching showed the largest values among the four relative spectral luminous efficiency functions over the whole range of visible wavelengths. The relative spectral luminous efficiency data obtained by heterochromatic brightness matching for the 2° and 10° fields here will provide data useful for development of a new photometric system where a great importance is to be attached to a correspondence between sensation of brightness and photometric quantity.

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The stimulus pattern on photo receptors produced by the image of the target is not the same as the luminance pattern of the target because the intraocular stray light due to the defect of the eye as an optical system superimposed on the retinal image. Therefore, if the visual problems are analyzed by using this actual luminous stimulus to the retina corrected by intraocular stray light, which we call “effective luminance;”, as an input to a visual system, then we can deal with the visual problems very simply. We have confirmed the availability and the applicability of the above concept through visual experiments and photographic luminance measurements using a single lens which simulates a human eye.

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We re-examined Helson’s (1938) complementary color which Cohen’s (1958) subjects could not observe in his partially inhomogeneous Ganzfeld. We found that even in the Ganzfeld similar to Cohen’s, Helson’s complementary color can be seen if several slight changes are made. The color appeared twice, just at the moment of the start of observation and again about a min. later, after which it remained almost constant in our experiment. We found that it is this latter color which corresponds to Helson’s complementary color, and that it is an afterimage color, not a discounted color or a contrast color.

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The fluorescent lamp with resistance ballast circuit has been investigated at the commercial frequency 50 Hz or 60 Hz through the computer simulation. The characteristics of fluorescent lamps can be expressed by the differential model equation of equivalent conductance. The model constants of differential model equations are determined by the multiple regression method and optimized by the simplex method, which the errorrate between the experimental waveform and simulation waveform are estimated. The resistance ballast operation circuit is assumed as a simplest model circuit for operating the fluorescent lamps. There are very good correlations between the measurement values aud the simulation values, and the accurate model equations of fluorescent lamp with resistance ballast circuit are able to predict.

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