Mao Xianglong, Li Hongtao, Han Yanjun, Luo Yi
Opt Express. 2014 Mar 10;22 Suppl 2:A233-47. doi: 10.1364/OE.22.00A233.
A two-step optimization method is proposed to design a compact single-surface far-field illumination system, satisfying the requirements of illuminance uniformity and light control efficiency with h/D less than 3:1. In the first step, the conventional tailored edge-ray design (TED) method is employed to generate prescribed illumination distribution for the rotationally symmetric optical system, and an optimization process is added to reach a balance between illuminance uniformity and light control efficiency. Based on the improved TED method, we can construct an initial optical system more accurate than that obtained by point source assumption. In the second step, an iterative feedback modification process is employed to optimize the initial optical system, so that the degradation of performance due to insufficient control of skew rays is mitigated. Because the initial optical system constructed in the first step is accurate enough, the second-step feedback modification can converge to a satisfactory result within several iterations. As an example, a free-form rotationally symmetric lens with the height of h = 25 mm is designed for a discoidal LED source with the diameter of D = 10 mm. Both high illuminance uniformity of 0.75 and high light control efficiency of 0.86 are obtained simultaneously. The method can be further used to achieve more complex non-uniform illumination distributions. The design of an optical system with h/D = 2.5:1 and a circular linear illumination distribution is demonstrated.
提出了一种两步优化方法来设计紧凑的单表面远场照明系统，该系统满足照度均匀性和光控效率的要求，且h/D小于3:1。第一步，采用传统的定制边缘光线设计（TED）方法为旋转对称光学系统生成规定的照明分布，并增加一个优化过程以在照度均匀性和光控效率之间达到平衡。基于改进的TED方法，我们可以构建一个比通过点源假设获得的初始光学系统更精确的系统。第二步，采用迭代反馈修正过程来优化初始光学系统，从而减轻由于对倾斜光线控制不足而导致的性能下降。由于第一步构建的初始光学系统足够精确，第二步的反馈修正可以在几次迭代内收敛到令人满意的结果。例如，为直径D = 10 mm的盘状LED光源设计了一个高度h = 25 mm的自由形式旋转对称透镜。同时获得了0.75的高照度均匀性和0.86的高光控效率。该方法可进一步用于实现更复杂的非均匀照明分布。展示了一个h/D = 2.5:1且具有圆形线性照明分布的光学系统的设计。
