(published in Journal of Lighting Engineering , March 2009, Vol. 20, No. 1, pp. 12-19) Zhuang Xiaobo Zhu Shaolong Zhang Shanduan Abstract: This paper defines three parameters that characterize the light output fluctuation of a source: wave depth, flicker index, and modulation depth. The linear illuminance sensor, photodiode, common illuminance probe and photomultiplier tube are compared to measure the fluctuation of light fluctuation. It is found that the illuminance sensor can meet the measurement requirements, and the photodiode can be used for simple measurement. The illuminance sensor is used to measure the fluctuation depth of various common light sources, and it is found that the fluctuation depth of the tungsten filament lamp is 6% to 31%, which decreases as the power increases. For fluorescent lamps, the inductive ballast has a wave depth of up to 42% to 48%; when using high quality electronic ballasts, the wave depth can be <10%. The metal halide light fluctuation of the square wave electronic ballast is <3%, which is less than 1/20 of the inductance ballast. The correlation between the instantaneous power waveform of the light source and the light fluctuation is analyzed. It is found that to make the light fluctuation depth small, the DC bus of the electronic ballast of the fluorescent lamp is required to be smooth, and the zero-crossing time of the instantaneous power of the high-intensity gas discharge lamp is as short as possible. Key words: light fluctuation; wave depth; scintillation index; modulation depth; zero-crossing time Measurement Methods and Impact Factors for Light Output Fluctuation of Light Sources Abstract Key words : light fluctuation ; δ depth ; flicker index ; modulation depth ; 1 Introduction The fluctuation of light output means that the light source is driven by AC or pulsating DC power. With the periodic variation of the current amplitude, the luminous flux, illuminance or brightness changes correspondingly, and the human visually represents the period of light with a frequency of 100 Hz. Sexual flicker, referred to as light fluctuation, commonly known as stroboscopic. The rapid flashing of the light source is not necessarily perceived by the human eye, but studies by Eysel et al. have shown that light fluctuations have an effect on the central nervous system [1], working or living under low-frequency flashing lights (such as inductive ballast fluorescent lamps) for a long time. It can cause symptoms such as visual fatigue and even headache [2]. The influence of fluorescent lighting fluctuations on visual function has aroused widespread concern [3-6]. How to accurately measure and analyze the light fluctuations of various light sources [7,8] has been reported abroad. Domestically, the [9,10] measurement of light fluctuations is not well-known, or the detector with a fast response [11] causes the measured light fluctuation to be small. China is a big country in light source production. With the large-scale popularization and application of straight tube fluorescent lamps, compact fluorescent lamps and high-intensity gas discharge lamps, it is necessary to evaluate the light fluctuation of existing light sources. This has great significance for improving production, learning efficiency and quality of life. This paper summarizes the definitions of three parameters that characterize the light fluctuation of the source, and compares the advantages and disadvantages of the fast linear illuminance sensor, photodiode, common illuminance probe and photomultiplier tube for optical fluctuation measurement, using illuminance sensor and photodiode for various The light fluctuations of common light sources were measured, and the effects of voltage, current and power waveforms on the light fluctuations were analyzed.
(Institute of Electric Light Source, Fudan University, Shanghai 200433)
Zhuang Xiaobo Zhu Shaolong Zhang Shanduan
(Institude for Electric Light Sources , Fudan Univer sity , Shanghai 200433)
Fluctuation depth (FD) , flicker index and modulation depth were defined to characterize the light variations of light s ources. F our detectors were compared , including linear illuminance sens or (LIS) , photodiode , conventional illuminance detector and photomultiplier. The results show LIS The FD of flicker index of generally 2 used light s ources were measured with LIS. The FD of tungsten filament lamps is 6 % to 31 % and estimates with Increased power. F or fluorescent lamps driven by magnetic ballast , the FD is 42 % to 48 %; and < 10 % by high quality electronic ballast . The FD of metal halide lamps driven by electronic ballast with rectangular waveform is < 3 % , which Is lower than 1?20 of that driven by magnetic ballast . The relationship between the power waveform and light flicker is analyzed. F or electronic ballast of fluorescent lamps , in order to reduce the FD the 50 Hz modulation has to be smooth , and for that of high intensity discharge lamps the zero passage at current reverse needs to be as shot as possible.