同时实现路面照度与亮度均匀性的LED光源光学系统研究

Study of the Optical Systems with Illuminance and Luminance Uniformity Simultaneously for LED Lighting

对于道路照明,人眼观察到的是路面的亮度而并非路面照度。理想的路面照明应能达到照度和亮度的双重均匀性。从发光二极管(LED)道路照明中路面亮度与照度的关系出发,提出了一种基于路面反射特性同时实现路面照度与亮度均匀性的设计方法。首先根据国际照明委员会(CIE)标准给出的简化亮度系数表计算路面上所有点的亮度系数;然后利用最小二乘法对路面照度和亮度同时进行分析,得到路面最优照度分布;最后采用分离变量与最小能量块迭代结合的方法对光源以及接收面进行网格划分,根据目标照度分布进行三维自由曲面光学系统设计,得到实现路面照度均匀与亮度均匀的光学透镜。将此设计应用于双车道的C1路面,实现了路面93.47%的照度均匀度,各车道观察到的路面总亮度均匀度为86.94%和89.26%。

For road lighting, the human eyes observe surface luminance rather than the illuminance. An ideal road lighting system should be able to achieve both the uniformity of illumination and luminance. A design method is presented to realize the illumination and luminance uniformity of road surface. According to the Commission Internationale Ed I＇eclairage （CIE） standard simplified luminance coefficient table, the luminance coefficient of all road surface points can be obtained. Then these parameters are analyzed by using the least square method, so as to obtain the optimal illumination distribution. According to the minimum energy block iterative methodology, we mesh both the light source and the receiving surface. With the three-dimensional free-form surface design method, the optical lens are obtained which can get the illumination uniformity of 93.47% and the luminance uniformity of 86.94% and 89.26% for a C1 double lane road surface.