以非成像光学为基础，设计了一种在大发散角范围内均匀配光的大功率LED室内照明二次配光透镜方案。采用划分网格法建立光源LED和接收面的映射关系，推导透镜自由曲面面形的一般方程，采用差分法求解透镜面形方程获得面形轮廓数据，再用三维软件建立透镜模型，通过光学仿真软件对所建模型进行光线追迹。结果表明：此方案适用于40°～140°配光角度要求的均匀配光；仿真配光角度120°的照明系统，当透镜的口径与LED发光面直径之比大于等于10时，照明系统的均匀性优于0.9，能量利用率大于92%，且照明效果不受接收面高度的影响。该设计方法为实现大功率LED室内均匀照明系统的小型化和简单化提供了一种有效的途径。

Based on non-imaging optics, a secondary optical lens is designed for indoor illumination of high-power LED which could illuminate uniformly in a large divergence angle. The mapping of LED onto the target plane is constructed by grid partition method, based on which the general equations of freeform surfaces are derived. The surface profiles are obtained by solving the equations using difference method. Using the profile data, the lens model is established with three-dimensional (3D) software. The optical system is simulated with ray-tracing software. This lens is fit for uniform illumination with the target divergence angle between 40° and 140°. A lens with 120° divergence angle lens is designed and simulated. The results show that it can keep the uniformity above 0.9 and the efficiency above 92% when the ratio of the lens aperture to the diameter of LED emitting surface is not less than 10, and the uniformity is not effected by the distance between the LED and the target plane. This design provides an effective way for the miniaturization and simplification of the indoor illumination system of high-power LED.