自由曲面反射器的计算机辅助设计

多曲面反射体车灯是目前高档轿车前照灯普遍采用形式。这种车灯具有很多优点，但其设计难度很大，必须依赖计算机辅助设计的手段，目前我国车灯企业不具备自主开发设计能力。为此研究了自由曲面反射式照明系统的设计理论和算法，采用多块均匀B样条曲面拼和构成的多曲面反射体，根据使用者提出的测试屏上不同位置的光型分布要求，从几何光学出发通过光路追迹确定曲面型值点的坐标，然后反算出控制顶点，得到满足复杂配光要求的自由曲面的结构参量，通过设置边界条件解决了分块式自由曲面反射器设计中棘手的区块间光滑连接的问题。研制的软件已能够从点光源出发自动设计出满足照明光型的多曲面反射体面型。

Computer Aided Design of Free From Reflector

Segmented reflectors are widely used in modern vehicle lamps. Such lamps have many advantages. However, they are difficult to design. Currently the Chinese vehicle lamp industry does not have a good CAD tool for the design of such lamps. Research is conducted for the design theory and algorithm for free form reflector illumination systems. The algorithm uses segmented reflectors made up of uniform B-spline surfaces in order to meet the specified illumination requests on different positions of the test screen. It can automatically generate shape points through ray tracing. Then it uses these shape points to calculate the control points of the surfaces. Constraints are added to make the adjacent segments connect smoothly with each other, and this solves a tough problem in the design of segmented reflectors.