为了使车辆驾驶员在雾、雪、雨或者尘埃等不同的恶劣气象条件下能够得到充分照明,且避免造成对方会车司机炫目,设计了具有明暗截止线的前雾灯系统。基于非成像光学理论,采用照度优化设计法,运用数值计算求解出自由曲面反射镜(FFR)各个点坐标的坐标值。合理划分基础面,并调整各子块的扩散角度,实现配光要求。通过蒙特卡洛模拟法进行追迹光线,测试结果表明：配光效果满足机动车前雾灯配光性能(GB4660-2016)对各测试点的照度要求,且明暗截止线清晰,体积小,边缘区域也有较高光能,光线利用率达到52.7%。

In order to make sure of adequate lighting for the driver in the fog, snow, rain or dust and other terrible weather conditions, and prevent the opposite driver from glaring, a front fog lamp system with a cut-off line was designed. Based on the theory of non-imaging optics, an optimal illumination design method was adopted and numerical coordinates were used to solve the coordinates of each point on the free-form surface mirror (FFR). To achieve light distribution requirement, the fundamental surfaces were divided legitimately and the spread angle of surfaces were adjusted. Through tracing the light with Monte Carlo simulation method,the simulation result shows that the final effect of light distribution fully fulfills the photometric characteristics of power-driven vehicle front fog lamps regulations(GB4660-2016), the optical system has a clear cut-off line, the volume is small,the edge area also has higher light energy, and the light utilization rate reaches 52.7%.