Research On Multi-color White Light Source Based On Visual And Non-visual Effects

Currently,under the rapid development of semiconductor technology,the fourth-generation semiconductor light source based on light-emitting diode(LED)has gradually occupied most of the lighting and display market.Compared with other light sources,LED light source exhibits the advantages of low voltage,low energy consumption,long lifetime and high reliability,and meets the national and social requirements for energy saving and environmental protection of lighting.In addition,the spectral power distribution(SPD)of LED is monochromatic,colorful,and tunable,so we can design the corresponding SPD to improve the light comfort by combining different wavelengths of LEDs according to our lighting requirements in different scenarios.Since the 21st century,the healthy lighting has become a popular research in the field of semiconductor lighting.Moreover,on October 2,2017,three scientists,Jeffrey C.Hall,Michael Rosbash,and Michael W.Young,were awarded the Nobel Prize in Physiology or Medicine for their research on the control of biological rhythms.It can be seen that the lighting source is closely related to the health of people's lives.This paper aims to establish the system of spectrum optimization algorithm for LEDs in the field of health lighting.The main research includes the following two aspects:(1)The research of three-color white LEDs for achieving indoor healthy lighting source.Specifically,we established the matching mathematical model for spectral simulation(asymmetric SP7 spectral model)for the three-color white LEDs composed of InGaN/GaN blue chip+YAG phosphor+AlGaInP red chip.The genetic algorithm was used to optimize the highest and lowest carcadian action factor(non-visual parameters)and corresponding lumimous efficacy of radiation(photopic parameter)for office lighting and bedroom lighting respectively.We believe that the relevant analyzed results can provide academic and industrial guidance for the implementation of the healthy three-color white LEDs.In addition,we compared the visual and non-visual characteristics of the four mainstream three-color white LEDs in two different lighting scenarios(office lighting and bedroom lighting).(2)The research of multi-color LEDs for realizing spectrally tunable light sources.In this part,we improved the least square method to ensure the non-negative of the solution.Firstly,we fitted two common standard light sources,namely A and D65,based on the asymmetric SP7 spectral model of multi-channel LEDs with equal peak wavelength interval,and theoretically verified the correctness of spectrally tunable driving algorithm by multi-channel LEDs.Secondly,we experimentally built a multi-channel LED light source system by the selection of the existing multi-wavelength LED products on the market.We measured the spectrum of each LED by the spectrometer and integrating sphere,and calculated the output current of each LED with the above-mentioned fitting algorithm.Lastly,the light source system with precise spectral adjustment was realized.