Research On Semiconductor Laser White Light Lighting And Light Distribution Technology

As a solid state lighting source with potential for development,the semiconductor laser white light sources have gradually become a research hotspot in related fields.The semiconductor laser white light source usually has three kinds of realization forms: multi-color laser mixing color,near-ultraviolet laser exciting RGB trichromatic phosphor and blue semiconductor laser exciting yellow phosphor to realize white light output.The method of exciting yellow phosphor by blue semiconductor laser has low color rendering,but it can meet the lighting requirements,and has the advantages of small size,high brightness,long working period and stability,which is the most promising industrialization method.Several conventional optical elements are needed in traditional lighting,by contrast,freeform surface design usually requires only one freeform surface to achieve the lighting requirements easily.The whole lighting optical system has smaller size,smaller optical loss and higher luminous efficiency,and the light type of the target surface is accurately controllable.By changing the local surface shape,the lighting effect of the target surface can be changed,so it has higher design freedom.This paper mainly focuses on the way of the blue semiconductor laser to exciting the yellow phosphor,and the application of the laser white light source in road lighting is studied by freeform surface light distribution design.The main research contents include the following three aspects:1.The influence of the concentration,thickness,position and shape of the phosphor layer on the light intensity distribution and chromaticity uniformity of the light source are simulated and analyzed by TracePro software.When the phosphor layer is circular shape,molar concentration 0.0205 mol/L,thickness 0.1 mm,and 2 mm from the bottom of the reflector,the light intensity of the light source approximately meet the Lambertian light intensity distribution,and the color uniformity of the light source reaches 0.009527 less than the value(0.01)of the color difference that the human eye can distinguish.2.To simplify the lens design,the laser white light source is considered as a "point source".The energy of the light source and the target surface are equally divided,and the freeform surface lens is constructed.The horizontal illuminance uniformity Ux of the spot is 81.88%,and the vertical illuminance uniformity Uy is 94.12% on the target surface.3.The laser white light source is substituted into the freeform surface lens based on the design of a "point source",Ux decreases from 81.88% to 65.31%,while Uy decreases from 94.12% to 84.56%.In this paper,the problem of lens optimization is transformed into two functions f(x)and g(y),which represent the degree of illumination deviation of the spot on the target surface.The size of the target surface mesh is redivided,and a new freeform surface lens is also constructed.The illumination uniformity Ux of the spot increases from 65.31% to 81%,and Uy increases from 84.56% to 92.89%.And the installation errors of the lens are studied.The horizontal,vertical and rotational tolerance are 0.15 mm,0.14 mm and 0.9 degrees respectively.