【作者】 陈飞；

【导师】 刘胜；

【作者基本信息】 华中科技大学 ， 光学工程， 2013， 博士

【摘要】 随着全球原油资源的紧张，使用传统光源的汽车前照灯已难以适应汽车节能需求，具备节能、环保、长寿命的LED光源是汽车前照灯的理想光源。LED汽车前照灯包括汽车前照灯专用LED光源封装以及灯具设计两大关键技术。其中汽车前照灯专用LED光源封装涵盖了封装结构设计、基板材料选择、LED芯片布置优化、贴片材料选择、荧光粉涂覆工艺、可靠性设计等方面。灯具设计则包含了配光设计、高效散热设计、驱动控制设计、光源可更换及灯头可转动的整灯结构设计，其中配光设计是前照灯设计的重中之重，关系到安全性、灯具的性能以及是否符合相关法规的要求。由于LED前照灯是未来汽车照明的发展趋势，以上各技术一直是各研究机构及企业研发的重点对象。本文围绕汽车前照灯专用LED光源的封装技术以及使用LED光源的近光灯及远光灯的配光设计技术进行研究并取得了以下进展：运用非成像光学原理，建立了适用于“点光源”LED封装的自由曲面配光透镜设计方法，该方法主要包括准直菲涅尔透镜的设计方法以及自由曲面的设计方法，运用该方法可以方便地设计出近光灯及远光灯的配光透镜。针对OSRAM OSTAR这款LED，设计了一款近光自由曲面透镜及一款远光自由曲面透镜。通过数值仿真，该透镜可以实现满足ECE标准的配光，并且光传输效率达到86%。运用光度学及非成像光学原理分析了汽车近光灯、远光灯配光对光源的需求，设计了运用于前照灯照明的专用LED的封装结构。其中优化了LED芯片的布局及荧光粉的涂覆形式及工艺，选用了特殊的封装基板，使得单颗LED不仅光通量达到1400lm，同时亮度超过20M nit，具有清晰的亮度截止线，光色满足ECE及GB法规要求。并根据以上设计制作了LED封装样品，用于测试及后续灯具的制作。针对以上开发的前照灯专用LED封装光源，通过改进现有的前照灯配光技术，建立了适用于LED光源的配光方法。该方法包括多曲面（MR: Multi-reflector）反光镜设计方法以及投射式配光（PES: Poly-ellipsoid System）设计方法。运用该方法，设计了多款适用于前照灯专用LED封装光源的光学元件，并且均能满足ECE及GB法规的配光要求。运用以上开发的前照灯专用LED封装光源及配光方法，开发了一款包含了LED近光灯及LED远光灯的前照灯样灯。通过测试，该样灯可以满足《GB25991汽车用LED前照灯》法规中关于配光的要求，另外该样灯在60℃的环境温度下，其散热翅片稳定时的表面温度低于80℃，结合模拟结果反推，LED芯片的节温低于115℃。进一步分析PES光学系统的光路，改进了PES结构，实现了集LED近光灯及LED远光灯于一体的双光LED前照灯模块，通过测试，该模块近光及远光灯均能满足GB的要求。更多还原

【Abstract】 With the consumption of traditional oil, it is difficult for headlamp with traditionallight source to meet the requirement of energy saving. However as the advantages ofenergy-saving, environmental protection and long life, LEDs are the perfect light sourcefor automotive forward-lighting application. There are two key issues in LED headlamp:automotive application specific LED package and design of lamp. Automotive applicationspecific LED package includes design of package structure, substrate material,optimization of LED chip array layout, phosphor coating, and design of reliability. Designof headlamp includes optical design, thermal design, powering and mechanical design,among which, optical design is the most important work because it is related to safety, theperformance of illumination and whether the lamp can meet the regulation. As LEDheadlamp is the trend of automotive lighting, these technologes have been the key objectsfor research institute and famous companies. This thesis will focus on the automotiveapplication specific LED package and optical design method for low-beam and high-beamlights with LED light sources and the advancements are listed as follows:Based on non-imaging optics, a design method of high efficient freeform lens forLED headlamp with ‘point light source’ packaged LED is developed. This method whichcan design freeform lens for low-beam and high-beam lights, includes the method ofcalculating Fresnel lens and freeform surface. With this method, a freeform lens forlow-beam light and a freeform lens for high-beam light based on OSRAM OSTAR aredesigned. The numerical simulation results show that these two lenses can comply withthe ECE regulation and have an optical efficiency of86%.The requirements of headlamp in optical aspect for light source are analyzed intheories of photometry and non-imaging optics. With the results of theoretical analysis, aautomotive application specific LED package is designed. This LED package has aoptimized LED chips layout and process of phosphor coating and special package board.This LED package can provide a luminous flux of more than1400lm and luminance ofmore than20M nit. In addition, there is a sharp cut-off line in luminance and the chromaticity coordinates can comply with ‘white’ of ECE and GB regulations. Based onabove design, some LED package samples are made for test and for LED headlampprototype fabrication.For automotive application specific LED package, a optical design method for LED isdeveloped through improving multi-reflector and poly-ellipsoid system. With this method,several optical elements of headlamp for automotive application specific LED package aredeveloped, which all can comply with the optical performances required in ECE and GBregulations.With above automotive application specific LED package and optical design method,a LED hedlamp prototype with LED low-beam and LED high-beam lights are made.Through optical test, the optical performances of this prototype can fully comply withregulation of “GB25991Automotive headlamps with LED light source(s) and/or LEDmodule(s)”. In addition, temperature on top surface of heat sink is less than80°C when theprototype is working under60℃, according to the simulation results, it can be predictedthat the junction temperature is less than115℃. Through analyzing the ray pathes ofpoly-ellipsoid system, a bi-light LED module with low-beam and high-beam is developed.The test results show that the optical performances of this module can comply with GBregulation.更多还原