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The paper analyzed the results of recent studies related to the effect of flickering light on the performance of visual work, well-being and human health. Besides, the authors described the methods for measuring the parameters of flicker and visibility of the stroboscopic effects, as well as safe levels of light modulation in different frequency ranges established by international standards. We studied the parameters of light flicker created by LED lamps and luminaires that are supplied to the Ukrainian market, the influence of the design features of these products on the level of flicker, and especially the measurement of light modulation taking into account the spatial heterogeneity of the LEDs. The modulation depth, flicker index, and stroboscopic effect visibility index were measured in accordance with the recommendations of the IEEE 1789:2015 and IEC/TR 63518:2018 standards using the MK350S spectrometer. To change the viewing angle, a GO2000 goniophotometer was used. The obtained results showed that the vast majority of LED lamps and fixtures have low levels of flicker and do not pose any risks to human health, but some manufacturers produce products that have a dangerous level of flicker. Conclusions were drawn about the necessity to introduce into the regulatory documentation the requirements for the limits of the modulation levels related to different frequency ranges observed in the LED products. It was found that due to the angular inhomogeneity of the spectral composition of the LED radiation, the angular inhomogeneity of the modulation depth also takes place. Based on studies of the depth of modulation depending on the viewing angle for various designs of luminaires, recommendations were made on improving measurement methods. |
