Study On Temporal Light Artefacts Effect Evaluation Index Based On Visual Fatigue

In recent years,the solid-state lighting(SSL)rapidly developed and has replaced traditional light sources such as incandescent and fluorescent lamps.Compared with the traditional light sources,LED has the characteristics of fast response and easy control,but it also brings some adverse changes,such as temporal light artefacts(TLA).Even though LED has a better control on TLA,the driving power supply ripple current and dimming mode may lead LED to generate more serious TLA than traditional light sources.Some studies have confirmed that TLA may cause visual discomfort,decreasing of work efficiency and potential threat to human health.With the constant development and advancement of lighting technology and the deeper of people’s understanding of psychological and physiology effect,solving the TLA problem is undoubtedly one key to achieve healthy lighting.A well-adaptable evaluation index is needed to realize the control of TLA.A lot of research on TLA had been carried out at home and abroad and proposed evaluation methods and corresponding limiting values,but they have not been well unified.Stroboscopic effect visibility measure(SVM)is currently the most recognized evaluation index of TLA internationally and has been recommended by CIE and IEC.However,SVM evaluation index is mainly based on the prediction of stroboscopic visibility and does not directly relate to the potential health effects of TLA.No effective conclusion has been drawn on if SVM can be used to predict the influence of TLA on health.Focus on the visual fatigue,we set four different levels of TLA and simulated a real office scene and we used the change of critical flash fusion frequency to represent the degree of visual fatigue,the reading speed and correct rate of characters to represent the visual efficiency to compared analyse the influence laws of TLA on visual fatigue under twenty conditions.Combined with the analysis of experimental data,we can draw some conclusions.Firstly,the aggravation of TLA can significantly increase the degree of visual fatigue.Secondly,SVM can be well used to predict the influence of TLA on health and the change laws of them is consistent.Thirdly,only when SVM increases to 1.6 in this experiment,the visual ergonomics ability of subjects decreases significantly and it is not obvious when SVM is 0.4 or 1.