《大功率LED封装与应用的自由曲面光学研究》由会员分享,可在线阅读,更多相关《大功率LED封装与应用的自由曲面光学研究(220页珍藏版)》请在金锄头文库上搜索。
1、华中科技大学博士学位论文大功率LED封装与应用的自由曲面光学研究姓名:王恺申请学位级别:博士专业:光学工程指导教师:刘胜2011-05-15华中科技大学博士学位论文 I 摘 要 随着大功率 LED流明效率不断提高、成本不断下降,大功率 LED在通用照明与特种照明领域得到了越来越广泛的应用,如 LED路灯、 LED背光、 LED汽车前照灯等等。高光效、光形可控与高空间颜色均匀度是实现高品质 LED照明不可或缺的三个关键因素。为了克服现有光学设计方法的不足之处,提高 LED照明品质,本论文围绕上述三个关键因素开展了 LED封装与应用的自由曲面光学研究,并取得以下创新性成果: 在光效与光形可控方面,
2、对于圆对称光斑点光 源情况,提出了一种新的任意配光曲线光源计算简单、任意出光角度准确可控的 LED均匀照明自由曲面透镜设计算法。 对于圆对称光斑扩展光源情况,提出了一套创 新的基于反馈优化的扩展光源自由曲面透镜设计算法,包括优化目标平面面积网格划分、优化光源能量网格划分与两者协同优化三种设计方法。有效克服了扩展光源对照明效果的劣化, UE 从 0.53提高到 0.90。 对于圆光斑空间整体均匀照明问题,提出了一 种新的逆向设计方法,包括优化配光曲线与实现任意配光曲线的新自由曲面透镜算法两部分。基于该方法,设计了两个集成自由曲面透镜的新型直下式背光用 LED模块,在大距高比时显著提高了 UE(从
3、 0.446提高到 0.915) ,同时大大减少了 LED数量( 1/4以下) 。 对于非圆对称光斑(例如常用的矩形光斑)点 光源情况,提出了一种改进的非连续自由曲面透镜算法,具有任意配光曲线计算简单、能量对应灵活、光形可控度高等优点。同时,提出了两种新的连续自由曲面透镜算法,分别为基于中心辐射与基于矩形网格能量对应关系。新型自由曲面透镜出光效率高,能够实现均匀的近似矩形光斑,已成功应用于 LED道路照明。 对于非圆对称光斑扩展光源情况,基于同样的 反馈优化设计思路,创新地提出了二次光学与一次光学相集成的应用导向型 LED 封装模块( ASLP),可实现均匀矩形光斑,能直接满足道路照明的需求。
4、 ASLP 具有体积小( 1/8) 、系统光效高(提高 8.1%) 、成本低(降低 17%) 、方便客户使用等优点。同时,设计了一基于 LED 阵列光源的道路照明用多功能集成 ASLP 模组,具有系统光效高(提高 19.4%)、维护替换方便等优点。 华中科技大学博士学位论文 II 对于非圆对称光斑空间整体均匀照明问题,以 实现亮度均匀道路照明为目标,提出了两种新的亮度均匀光学设计方法,分别为组合法与亮度均匀自由曲面透镜算法。这两种方法都显著提高了道路亮度均匀度, UL 从 0.30迅速提升到 0.70,并已经成功应用于实际 LED道路照明。同时,提出了一种新的亮度均匀非对称自由曲面透镜设计算法
5、以提高道路照明利用率,平均亮度提高了 25%。 除了光效与光形可控方面,对 LED照明空间颜色均匀度( SCU)也进行了研究。提出了一种采用自由曲面透镜来提高 LED照明 SCU的新方法。集成自由曲面透镜的新型LED封装模组的 SCU从 0.334增加到了 0.957,并且对不同荧光粉层 结构具有较好的稳定性与一致性。同时,采用空间颜色 均匀自由曲面透镜能够大大降低 LED的 uv值,提高 LED照明品质。该新方法具有工艺简单、成本低、光效高、效果显著等优点。 本文提出了一系列创新的自由曲面透镜设计算 法与空间整体均匀照明设计方法,并基于这些算法设计了多种新型自由曲面透镜与新型 LED封装模块
6、,为实现光效高、光形可控、空间颜色均匀的高品质 LED照明提供了一套有效的光学解决方案,将可以在 LED通用照明与特种照明中得到广泛应用。 关键词: 大功率 LED 自由曲面光学 透镜设计算法 扩展光源 光形可控 空间颜色均匀度 应用导向型 LED 封装 华中科技大学博士学位论文 III Abstract High power light-emitting diodes (LEDs), with increasing luminous efficiency and cost performance in recent years, have more and more applications
7、 in general lighting and special lighting, such as LED road lighting, backlighting for LED TV, LED headlamp of automotive, etc. High optical efficiency, controllable radiation pattern (RP) and high spatial color uniformity (SCU) are three key issues to realize high quality LED lighting. To overcome
8、drawbacks of current optical design methods and to enhance the quality of LED lighting, this dissertation mainly focuses on the research of freeform optics design for LED packages and applications based on these three key issues. Achievements are as follows: In the aspect of optical efficiency and c
9、ontrollable radiation pattern, for the condition of circular-symmetry RP and point source, we propose a new freeform lens algorithm for LED uniform illumination, which makes the calculation simpler for light source with arbitrary light intensity distribution curve (LIDC) and is able to have an accur
10、ate control of emitting angles. For the condition of circular-symmetry RP and extended source, we develop a novel freeform lens algorithm based on feedback optimization for extended source problem, including three sub-methods of optimizing the division of target grid, optimizing the division of ligh
11、t source grid and co-optimization design methods. These three methods provide effective ways to overcome the deterioration of RP caused by extended source and enhance the UEsignificantly from 0.53 to 0.90. For the condition of whole lighting performance of circular-symmetry RP, we develop a new reve
12、rsing design method for LED uniform illumination, including optimization of LIDC and a new algorithm of freeform lens to generate the required LIDC. According to this design method, two novel LED modules integrated with freeform lenses for direct-lit backlighting are successfully designed to enhance
13、 the UEfrom 0.446 to 0.915 in the situation of large distance-height-ratio, and the quantity of new LED modules dramatically decrease to less than 1/4 quantity of traditional LED modules. For the condition of non-circular-symmetry RP (e.g. rectangular RP) and point source, we propose an improved dis
14、continuous freeform lens algorithm with advantages of arbitrary LIDC available, flexible light energy mapping relationship and shape of RP highly controllable. Moreover, we also develop two new algorithms for continuous freeform lenses, which are the design methods based on the radiate grid and the
15、rectangular grid light energy mapping relationship respectively. Uniform rectangular RPs are able to be achieved by these 华中科技大学博士学位论文 IV freeform lenses, which have been applied in LED road lighting successfully. For the condition of non-circular-symmetry RP and extended source, based on the feedba
16、ck optimization design concept and the integration of secondary optics with the primary optics of LED package, we develop a novel application specific LED package (ASLP) module, which is able to achieve rectangular RP meeting the requirement of road lighting directly. ASLP has advantages of small size (1/8), high system optical efficiency (enhanced 8.1%), low cost (decline 17%) and easy for customer to use. In addition, a new ASLP modul