Study On High Quality White Light Based On Blue Laser Diode And Phosphor

The research on white light source coming from semiconductor laser exciting fluorescent power synthesis has become one of hot points of fixed state lighting area.Especially after BMW and Audi Corporations have released laser automotive headlamp one after another,scientists of all countries have developed the research on LD white source competitively.This article develops research and provides theoretical basis aiming to improve the color quality of LD white source.First,the article expounds the purpose and significance of the topic,analyzes characteristics of generative mode for several LD white light,introduces the developing history,classification,advantages and disadvantages,application prospect and research situation for the technology at home or abroad,as well as feasibility of applying in lighting area.Then the article introduces the formation principle and key components for LD white light.It selects 456 nm semiconductor as excitation source of LD white source,based on different property of different laser with requirements of the topic,and selects YAG fluorescent power and nitride power as excitation object based on chemical property and emission spectrum for different fluorescent powers.1.Derive the variation relationship between radiation quantum efficiency and current density theoretically.From the computation,we can see,LED can acquire very high radiation quantum efficiency while it is in low current density,with peak efficiency generated when current density is 2.44A/cm~2,after that it will reduce sharply with the increasing of the current density.The radiation quantum efficiency of LD is zero while current density is below light threshold,but after reaching light threshold,the radiation quantum efficiency of LD will increase quickly and will exceed LED while the current density is 4.85×10~3A /cm~2.2.Research the difference of LD&LED white light under the same fluorescent power setting by simulation.The results indicate that LD white light is inferior to LED white light on color parameters,such as color temperature,color coordinate.But these parameters can reach ideal relative values of white source through changing laser divergence angle and fluorescent density,and this are verified by the test.3.It computes the variation rule of LD white light source CRI with yellow,red fluorescence spectra in fluorescent power on theory,given the emission spectrum of fluorescence power.The results indicate that the CRI of LD will reach the highest 79.21 while the ratio of yellow,red fluorescence spectrum power in the given fluorescence power is 1:0.7.4.It researches the effect of fluorescence power with different yellow and red matching to the LD white light source,using blue light LD with wave length 456 nm as excitation source.The test results indicate that the LD white light CRI will improved greatly along with the increasing ratio of red power in the fluorescence power,and the best CRI brought from the article is 76.6.