提出了一种用于扩展发光二极管(LED)光源配光的自由曲面透镜设计方法。利用加权叠加点光源透镜的母线,设计得到了自由曲面透镜,构建了反映照度均匀性的评价函数,自变量为三个权重因子。利用粒子群算法优化权重因子,使评价函数达到最小值,此时照度的均匀性最高。目标面上的均匀度从初始结构的78.93%提高到90.67%,同时光效保持在92%以上。对透镜分别进行加工误差分析和横向公差分析,结果表明,当加工误差在-1.0~1.0 μm范围内、横向位移误差在0.0~0.2 mm范围内时,目标面照度均匀度所受影响较小。

An algorithm used to design a free-form lens for the extended light-emitting diode (LED) source is proposed. The design of a free-form lens is realized by the overlap of the weighted lens profiles of several point sources and the evaluation function reflecting the illumination uniformity is constructed, in which the independent variables are three weighting factors. The particle swarm algorithm is used to optimize the weight factors and minimize the evaluation function, and thus the illumination uniformity is the highest. Correspondingly, the illumination uniformity on the target surface increases from 78.93% for the initial structure to 90.67% and simultaneously the light efficiency is kept above 92%. The fabrication error analysis and lateral tolerance analysis of lens show that the influence on the illumination uniformity on the target surface is small when the fabrication error is within the range of -1.0-1.0 μm and the lateral displacement error is within the range of 0.0-0.2 mm.