自由曲面匀光透镜被广泛应用于发光二极管(LED)照明中。传统的基于几何近似的自由曲面求解方法，由于存在建模误差，导致求解的面型不够精确，照明面均匀性下降。提出了一种误差分析及补偿方法，通过建立面型误差和出射角度误差之间的联系，结合光线追迹，实现了面型误差的准确量化和修正。采用该方法，针对1000 mm 工作距离，直径200 mm 照明范围的景观照明透镜进行了补偿设计，并用Lighttools 软件进行了仿真。结果表明：点光源模拟情况下，相对于传统几何近似求解方法，照明均匀性(最小照度/平均照度)由68.0%提升到98.5%；1 mm×1 mm尺寸LED 光源模拟情况下，在直径160 mm 的照明范围内，均匀性达到91.8%，具有良好的实用性。

Uniform illumination free-form surface lens has been widely used in the light emitting diode (LED) lighting. However, due to modeling error in traditional freeform surface solution based on geometrical approximation, the surface shape can not be solved accurately and result in the decline of illumination uniformity. A method of error analysis and compensation algorithm is proposed. The relationship between emitted light angle error and free-form surface error is established, combined with the ray tracing, quantifying and correcting for surface error accurately. According to the method above, it is suggested that the compensation design of landscape lighting lens in which the working distance of the lens is 1000 mm and target panel diameter is 200 mm. The simulation result shows that after importing the lens modeling into Lighttools software demonstrate, compared with the traditional design method, the illumination uniformity is increased from 68.0% to 98.5% under the condition of point light source. And the uniformity is reached up to 91.8% with the diameter of 160 mm lighting area and the condition of 1mm×1mm size of the LED source. The optimized lens has good practicability.