Study On Light Environment Evaluation And Related LED Spectrum

With the increasing application of LED lighting products,the lighting quality of light sources,that is,the evaluation of the light environment of the light sources has received much attention.It includes the radiation safety of the light sources and the color quality of the light sources.The radiation safety of LED light sources focuses on its blue light hazard,and the color quality of light sources includes fidelity,preference,naturalness,saturation,color constancy,color discrimination,etc.These are all closely related to their spectral structure.In this paper,the research on the LED spectrum is used to optimize the blue light hazard and color gamut area of the light sources while maintaining the same color temperature.The effects of light sources with different spectral structures on subjective color quality evaluation are obtained through psychophysical experiments.First,the monochromatic light with a peak wavelength of 380 ~ 780 nm is superimposed on different color temperature light sources is simulated,and the total radiant power of the light sources is kept unchanged.The color temperature and blue light hazard changes of the light sources after superposition are calculated.The results show that when the wavelength of the superimposed monochromatic light is in a band with a large value of the hazard weighting function,the blue light hazard of the light sources increases.The three color temperature light sources are superimposed on monochromatic light with wavelengths of about 576 nm,567nm,and 538 nm,respectively,the color temperature of the light sources remains unchanged and the hazard of blue light is reduced,at the same time,the color rendering index is also significantly reduced.For the light sources with the highest blue light hazard value among the sample light sources,when the monochromatic light of 460 ~ 470 nm and monochromatic light of 655 ~ 660 nm with different amplitude powers are superimposed at the same time,the color temperature of the light source remains basically unchanged,and the color rendering index increases by about 10 ~ 12,the blue light hazard value is reduced by about 8 ~ 17 W/m~2/sr,and the light efficiency is reduced by about 14.8% ~ 18.4%.The purpose of optimizing the blue light hazard of the light source by maintaining the color temperature is achieved,and the maximum allowable exposure time of the light sources can be appropriately increased to reduce the possibility of potential blue light hazard.Secondly,the same method is used to superimpose the monochromatic light on different color temperature light sources to optimize the color gamut area of the light sources.The results show that the superimposed monochromatic light in the 380 ~ 465 nm or 605 ~ 780 nm band has an increased color gamut area;the superimposed monochromatic light in the 470 ~ 600 nm band,the color gamut area of the light source is reduced.Take a spectrum of increased and decreased color gamut after light sources superposition to perform light box matching and visual experiments.The results show that the color vividness and color preference under the light sources with increased color gamut are higher than those with reduced color gamut,and the change of the color gamut area of the light sources after superimposing monochromatic light is verified.Taking one light source from each color temperature and superimpose two monochromatic lights with different amplitude power and wavelength at the same time.As a result,the absolute value of the color difference deviation value was less than 0.007,and the color temperature was basically unchanged,and the color gamut index increased by about 2 ~ 10.The purpose of optimizing the color gamut area of the light source is achieved while keeping the color temperature basically unchanged.Increasing the color gamut area of the light source can appropriately increase the color saturation of the object under the light sources illumination.It has important application value for the light sources design of the lighting environment with high color quality requirements.Finally,in order to obtain the influence of the light sources with the same color coordinates on the subjective evaluation of the lighting quality,six white light sources with the same color coordinates and the same color temperature were matched by a light box.Subjective evaluation experiments on the brightness,vividness,and color preference of different color samples under its illumination were performed.The subjective evaluation experiment results are statistically analyzed using SPSS multivariate analysis of variance.The results show that the spectral structure and color of the samples have significant effects on the subjective evaluation of brightness,vividness,and color preference,which is important for the study of subjective evaluation of light sources quality.