Research On Dimming Application Of Light Biological Effect In LED Lighting

With the In-depth study of experts and scholars,people have a clearer understanding of the photobiological effects.Studying lighting dimming technology that takes into account both visual and non-visual biological effects is the next direction in the development of lighting science.Compared with traditional lighting scientific research,new research methods and research content are imported into the lighting study.As a fourth-generation new light source,LED(Light Emitting Diode)have great advantages compared with traditional light sources,the characteristics of green,energy saving,high luminous efficiency and long service life make more and more LED lighting devices applied in urban lighting,home lighting,automotive lighting and electronic display screens.The light emitting principle and the dimming method of LED are very different from the traditional light sources.Therefore,it is necessary to study the application methods and techniques of the LED lighting in both the visual and non-visual biological effect lighting science.The content of this paper is divided into two parts.The first part aimed at optimizing the adjustment strategy of LED light source in practical lighting applications and studied the tunability of the photobiological effects of different LED light sources.By analyzing the tunability of biological rhythm factors and blue light damage in three kinds of LED light(RGB LED,ordinary three-color temperature LED,and composite three-color temperatures LED)we got that:the biological rhythm factor and the blue light hazard factor of the RGB LED light source have the largest tunable range corresponding to one certain correlated color temperature(CCT),and then the ordinary three-color temperature LED lights and the composite three-color temperature LED lights.In any one of the three kinds of light source,the tunable range of the biological rhythm factor and the blue light hazard factor reaches the maximum at“the middle CCT" of the hybrid light source.By analyzing the tunability of the blue light hazard factors which refer to biological rhythm factors of the above three light source we got that:the blue light hazard factors increase with the increase of biological rhythm factors in three kinds of light source,the tunable range of blue light harm factors from the largest to the smallest is the three primary color LED light source,the common white light LED light source,and the composite white light LED light source under the one certain rhythm factorOn account of the importance and complexity of photobiological effects,in the second part we studied the relationship among illumination,CCT,rhythm factor of three-channel hybrid light source and PWM channel ratio in practical lighting applications,and a dimming calculation model that combines both visual and non-visual biological effects is proposed.By experiments,it was found that illumination,CCT and rhythm factors all showed a linear correlation with channel ratio,the slope difference of the straight line between the actual fitted line and the theoretical relationship is less than 6%,and the intercept difference is less than 5%.The significance of the normal distribution of actual rhythm factors and theoretical results was tested by significant differences and it was found that there was no significant difference between the two results.The illuminance of mixed light source,CCT and rhythm factor present a matrix relationship with three-channel proportional factor,by the matrix relationship,the three-channel ratio can be calculated conveniently according to the three parameters of the hybrid light source,and the three parameters of the hybrid light source can be quickly calculated according to the three-channel ratio.