The Light Guide System In The Automotive Lighting Applications

The goal of the thesis is to do some exploring research for light guide system applied in the automotive lighting.In recent years, with the development of automotive industry, people pay more and more attention to the quality of the automotive lighting. The light guide system applied in the automotive lighting is a new research field. After getting familiar with the development of the automotive lighting and light guide system and learning the foreign experience in this field, the author put forward a design which is a front position lamp used fiber optics. The front position lamp combined with LED which is a new type light source can meet the requirements of ECE and GB by certain optical design. A new concept that all the lamps in a car use one light source by applying light guide system comes up. Therefore, it is hoped that the design can give some experiences in such new direction.At first, the development of automotive lighting and light guide system is reviewed. Starting with the theory of light guide, a side lighting solution based on micro prism is put forward, which describes how to control the direction and amount of side lighting by the angle and size of micro prism respectively. Combined the light guide using such solution and LED light source by simple direct coupling, the front position lamp light guide system is made up. The process concerns the selection of light source and light guide material and the way of coupling.Then, the computer simulation using software called Tracepro is discussed, and the intensity distribution and spatial illuminance distribution is obtained. It can be found that the simulation result gets accordance with the theoretical analysis on the side lighting affection of micro prism, including angle, size and spatial density.At last, photometric measurements on the sample is discussed. The flux and efficiency of the sample can be calculated through the data, meanwhile the intensity distribution curve can be plotted. The result shows that the measurements get accordance with the analysis and simulation. It is calculated that the effective efficiency of the sample is 40% and 30%. Compared with the general light guide system of 20%-35% efficiency, it is relatively high since the coupling light loss is less in this design. But in the other hand, much light are not utilized in the other half space, which needs further improvement.It is important that the sample meet the ECE and GB requirements of minimum horizontal angles and light distribution. The further research is aimed to enhance the system efficiency, improving the light utilization.