Reduction of flicker of light sources is one of the important factors for comfort lighting. Reduction of flicker of light sources seen directly, for example portable desk standards mounted with a fluorescent lamp is very important. Especially, flicker sensation is more from alternate diferent light waves such as the flicker of the both parts of the fluorescent lamp. At first, the experiments containing subijective appraisals were made, in order to choose the most relevant index from the conventional indexes such as the Flicker Index. As a result, it was found that relations between respective indexes and flicker sensation from the flickering light were not sufficient. In the second place, as a new provisional index, the ratio of the two average luminances of the alternating light waves that were divided by the respective wave durations has been propesed and confirmed that this index has sufficient relation to flicker sensation through the experiments of subjective appraisals. This has been named “Flicker Luminance Ratio”. At last, experiments of subjective appraisals were made to find out the practical limit of flicker sensation of the portable desk standardes quantitatively using the “Flicker Luminance Ratio”. For the design objective of the desk standard, 0.92 has been determined to be proper for 50 Hz light waves.
Recently, the electronic ballast or the high frequency invertor for fluorescent lighting came into practical use as the energy saving has been eagerly required after “the petrol crisis”. The electronic ballast, of course, being more expensive than core-coil ones in initial costs, never-the-less the electronic ballast exhibits higher total economical possibilities. In this paper, fluorescent lighting devices were studies in their over all economical functions. Criteria for designing electronic ballasts were also obtained as follows. (1) The dark angle should be extinguished. (2) Lamp currents should be chosen just as their “standard value” of catalogue data.
Pulse starting of metal halide lamps requires the voltage between 1.0 to 1.5 kV. The starting voltage greatly depends on whether lamp starting is accompanied by the discharge between the main and the auxiliary electrodes or not. It is well known that, when a glow-starter is used as an ignitor and a current limiting resistance is in the range of 100 to 500 ohms, the pulse voltage lowers according as the resistance increases, while the pulse repetition rate slightly increases. However, in our experiments, when the current limiting resistance further increased and rose above 1.0 k ohms, the pulse repetition rate steeply increased, and reached about 500 times of the case of 300 ohms. Then, the breakdown voltage between the main and the auxiliary electrodes lowered. Therfore, it was proved that the starting characteristics of the lamps could be improved considerably although the pulse voltage lowered to the 600 to 700V level.
Light output of the ordinary discharge lamps operating on A. C. power supply shows cyclic variation similar to A. C. input power, and whose frequency is twice of the A. C. input power. This variation of light output is called “FLICKER”.“FLICKER INDEX” and “PERCENT FLICKER” have been proposed as ideas to evaluate the flicker of light sources. However, they cannot offen accurate evaluation of the flicker, because actual sensibility to the human eye may differ even if they have the same numerical values of evaluation measured under the same measuring conditions. To increase accuracy of evaluation, “FLICKER BY DISTORTED WAVE” is introduced as new concept. This new method of evaluation is realized by checking the lower harmonic component after harmonic analysis of light output applying “FOURIER SERIES”. We recognize through our repeated experiments that the results evaluated by this “FLICKER BY DISORTED WAVE” are conformed to actual sensibility of flicker.