Research On The Algorithm For Revising Freeform Surface Based On LED Street Lamp Design

In LED street lamp design, it is always a focus that how to create the suitable freeform lens structure with given illumination distribution. At present, there are mainly three kinds of design methods regarding, mathematical design method, geometrical design method and optimization design method.Though research on algorithms for free-from lens design started late, it ignited the passion of many scientists in China. And some outstanding methods has emerged. However, many of them are not available to the public because of trade secrets protection, thus they can not be widely used in industry.My project derives from the cooperation project with a lighting company, whose final goal is building an automatic or a semi-auto optimization platform for LED illumination design. Thus my work can be divided into two parts. First, my research focuses on the optimization design methods of free-form lens so as to ensure that these lenses are producible. Second, optimization platform should be designed and written so that laymen are able to use it after some basic training.In this thesis,the meaning of the research and the research status worldwide were introduced first. Then the design method based on u-v meshing and that based on Runge-Kutta method were described in detail. And design examples regarding were given. Next, the problem of expressing freeform surface was introduced. But this will not be a theme here. In view of the final goal of the company, we first proposed design methods based on the feedback from the illumination map and methods based on operations research method. These algorithms and flowcharts can be found in Chapter 4. At the end of each section, an example was given.After analyzing previous work, new optimization algorithm method was put forward in Chapter 5. There are two points should be noted. First of all, because of its weakness in expressing freeform surfaces, previous platform was replaced by another one. Second, in order to make the design process more flexible, we applied Runge-Kutta method other than u-v meshing method in Chapter 5 to calculate freeform surfaces. Also, an example and analysis of the optimization strategy were given at the end of the chapter.The final chapter summarizes the whole thesis and describes ideas for future work.