Design And Experimental Research On Uniform Illumination System Of Surface Light Source

With the LED package and the manufacturing process continued breakthrough innovation,LED chip performance even more stable,gradually shine in the lighting field.In particular,the compact integrated LED surface light source has a better market application prospect due to the advantages of low price,good heat dissipation,and high luminous flux.In different lighting application scenarios,the lighting requirements for LEDs are also different,but both in the field of general lighting stage lighting such or special lighting light pulses engine belongs,pursuit of high uniformity and high efficiency of the illumination beam.Therefore,the research of uniform lighting system of LED surface light source has always been a hot issue in the development of LED technology.Under the guidance of non imaging optics theory and genetic optimization algorithm,this paper studies and designs a narrow beam uniform illumination system composed of compound parabolic reflector,Fresnel lens and aspheric lens,and a free-form surface uniform lighting system based on energy mapping and genetic algorithm optimization,and the simulation results show that high uniformity illumination beam can be obtained.The specific research contents of this paper are as follows:Aiming at the shortcomings of traditional lenses or reflectors for collimating and uniform light distribution of high-power LED surface light sources,this paper proposes a narrow beam uniform lighting system based on a combination of multi-level light distribution.Firstly,a compound parabolic concentrator is designed for the first condensing of the LED based on the edge ray theory.The LED light source is compressed at about 60°,and then the Fresnel lens is used to control the spill light,and then the aspheric lens is used to achieve the collimated output of the light.The designed system is processed into a real object for testing.The experimental results show that the system can achieve a circular spot with a divergence angle of about±7.9°,a uniformity of more than 96.04%,and a light efficiency of more than 60% in an area 700 mm away from the system.Considering that the combination of multi-level light distribution will cause light energy loss and the optimization limitations of aspheric lenses,this paper further proposes a free-form uniform light illumination system based on energy mapping and genetic algorithm.First,a design scheme for a uniform lighting system based on low-power LEDs is proposed.The mapping relationship between the luminous flux of the LED light source and the target receiving surface is established according to the free-form energy mapping method,and then combined with Snell’s law,the coordinate data of the free-form plano-convex lens is obtained by iterative calculation,Get the solid form of the lens through Solid Works modeling.In this paper,6 chips with different sizes are used for simulation.The results show that when the chip size is small and can be regarded as a point light source,the light distribution effect of the lens is better,the uniformity exceeds 93.4%,and the light efficiency reaches 89%;When it is larger,the light distribution effect of the lens becomes worse as the chip size increases.Aiming at the problem that the light distribution effect of lens designed based on low-power LED is not good for large-size LED surface light source,this paper combines genetic algorithm and DDE dynamic transmission technology to realize the fast exchange between the new coordinate data calculated by Matlab and the performance index data obtained by Trace Pro simulation,thus greatly improving the optimization efficiency.After multiple iterations of variable optimization,a lens for the light distribution of the LED surface light source is obtained.Then the simulation of a chip with a diameter of 6mm shows that the system can form an illumination spot with a uniformity of more than 91.7% at a distance of 1000 mm,and the light efficiency reaches 87.5%.