Research On Automatic Optimization Design Of Several LED Freeform Lenses With Extended Source

With the improvement of LED power and lumen efficiency and the reduction of cost,LED has become more and more widespread in the lighting field,especially the extended LED source which is smaller and more compact,has more market value.When designing the surface of the LED lighting system,the freeform surface is gradually replacing the conventional surface with its excellent local operation and high design freeform.This paper focuses on studies of the large-angle circular illumination,rectangular illumination with low Fresnel loss,and freeform lens design with off-axis rectangular illumination in terms of the extended LED lighting.An artificial intelligence optimization algorithm such as BreedPSO,SimuAPSO,etc.is combined by the overlapping method to break through the local optimal solution.Furthermore,the automatic data transmission function of dynamic data exchange technology(DDE technology)is used to solve the problem that a large amount of data needs to be transmitted between MATLAB and TracePro hundreds of times and manual operations are difficult to complete.In the end,through simulation design experiments,a variety of freeform lens designs have been implemented to achieve integrated automatic optimization of lighting system calculation,modeling,ray tracing,feedback lighting effects,and optimization.1.Research on the automatic optimization design of double freeform surface lens with large view angle and circular uniform illumination has been conducted.Firstly,an angle expansion function is created to make the inner freeform surface diverge the light effectively and a double freeform surface lens with large view angle based on a point light source is constructed.Furthermore,the extended light source is optimized by overlapping method as the initial structure of the target lens.BreedPSO algorithm is adopt to optimize the structure on MATLAB and automatic programming and simulation is implemented by using Scheme language programming on TracePro.Finally,automatic transmission of data between optimization and automatic modeling is achieved by using DDE communication technology.This paper takes a compact lens design with h/d=2.5 as an example.With this design method,the beam angle can achieve 150°,the uniformity and light efficiency reach 88.12% and 84.54% which is 3.68% and 0.53% higher than the BreedPSO algorithm alone respectively.2.For the condition of lighting efficiency of lighting system,this paper focuses on the Fresnel loss of the freeform lens realizing rectangular illumination with extended source.Firstly,the minimum Fresnel loss calculation and optimization are performed for the rectangular illumination of a point light source.Based on the one-dimensional overlapping method,a twodimensional overlapping method is proposed to solve the problem of overlapping arrangement of virtual point light sources in rectangular illumination of extended source,then the initial structure could be established.Furthermore,the value of the radius and the height of the inner surface,and the data of the outer surface are set as the optimization parameters,then the lighting efficiency and target uniformity are weighted to construct the optimization function.Finally,the lens is optimized by using the SimuAPSO algorithm to achieve uniform rectangular illumination with low Fresnel losses.Taking the compact lens with h/d=3 as an example,the light extraction efficiency of the rectangular illumination lens obtained by this optimization design method is 91.958%,which is only 0.337% lower than that of the ideal hemispherical point light source illumination system.At the same time,the uniformity reaches 79.86%,through road simulation,which meets M1 standard that is the strictest road lighting standard.3.Research on the automatic optimization design of freeform lens for off-axis rectangular illumination with extended source is conducted.Firstly,when modeling the off-axis rectangular lens automatically,there is a problem of modeling failure probability in the slice method.An integrated slice method modeling is proposed to realize that the freeform surface lenses with different mesh divisions can be constructed by the Scheme language in TracePro,avoiding modeling failure which may affect the optimization of off-axis lighting system automatically.Secondly,on the selection of optimization variables,it is proposed that the conventional optical optimization variables such as the lens and the target surface and the mechanical variables such as the lateral and longitudinal positions of the light source in the lens surface be used together as an optimization variable to optimize lens and the installation position of the light source simultaneously.Relative to optimize the conventional optical variables only,there is more design freedom.Taking a compact lens with h/d=3 for road lighting as an example,a rectangular spot of 15×8m at a distance of 6m and a width of 1.5m from the axis is used to optimize the lens parameters and the installation parameters of the light source.The uniformity and energy collection efficiency is 75.03% and 85.12% respectively,the uniformity can meet the road lighting demand and there goes a high the energy collection efficiency relatively.