一种新型白光LED荧光粉层结构的设计与优化研究

发布时间：2018-06-10 13:30

本文选题：白光LED + 优化结构　；参考：《电子科技大学》2016年硕士论文

【摘要】：近年来,白光LED发展迅猛。但是由于白光LED不像其他光源是均匀发光,所以白光LED在空间色温分布上还是存在着不均匀的情况。为了减少人们对于色温分布不均匀造成的不舒适感,提高白光LED的品质,改善白光LED的色温分布均匀性非常必要。本文将通过建立白光LED的光传输模型,深入的了解影响色温分布均匀性的物理机制,对白光LED封装结构进行系统的研究,提出一种改善白光LED色温分布均匀性的封装结构,在模拟的基础上,进行实验验证,证明了这种新型的封装结构能够有效地改善白光LED的空间色温分布均匀性。首先,建立白光LED的物理模型。物理模型包括蓝光LED的MQWs(Multiple Quantum wells)模型、Mie散射模型、荧光粉粉层的结构模型、边界模型、相关色温计算模型、白光LED传输模型。使用Monte Carlo方法模拟白光LED的光学特性。在光强自适应封装结构的基础上,提出了一种基于光强自适应的新型曲面封装优化结构。优化结构由光强自适应层和传统点胶层两层构成,第一层是光强自适应层,第二层是传统点胶层。模拟结果显示,在色温均匀性上,优化结构优于光强自适应结构。通过仿真和实验发现,优化结构色温均匀性优于光强自适应结构。平均色温5200K左右时,优化结构较光强自适应结构的ACU提高了7.85%,发光效率提高了33.3%。并将优化结构与在光强自适应层上涂覆硅胶层的封装结构进行对比,优化结构的空间色温均匀性更好,平均色温4900K时,发光效率提高12.2%。接着,研究不同工艺和结构参数对优化结构性能的影响。将自适应层厚度变化和传统点胶的浓度变化进行实验对比,研究它们对新结构的光学性能的影响。得到改进工艺和结构参数之后的优化结构,使用1 A的曝光电流曝光,传统点胶层的浓度为1:9。平均色温为5500K时,优化结构的空间色温标准差为75K,发光效率达到92.1 Wlm/;自适应结构的空间色温标准差为195K,发光效率为68.5Wlm/;在自适应层上涂覆硅胶层结构的空间色温标准差为135K,发光效率为83.9Wlm/。空间色温标准差分别减少61.5%和44.4%,发光效率分别提高34.4%和9.7%。优化结构在色温均匀性上提高,而且效率与自适应结构相比得到提升。最后利用边缘光线理论和能量守恒定理,设计基于自由曲面透镜的封装结构。使用Monte Carlo方法模拟后发现,其空间色温分布均匀性好。在色温为5200K时,ACU(Angular Color Uniformity)大于0.98,最大色温差为107K。
[Abstract]:In recent years, white LED is developing rapidly. However, because white LED is not as uniform as other light sources, white LED still has uneven color temperature distribution. In order to reduce the discomfort caused by the uneven distribution of color temperature and improve the quality of white LED, it is necessary to improve the uniformity of color temperature distribution of white LED. In this paper, by establishing the optical transmission model of white LED, we will deeply understand the physical mechanism that affects the uniformity of color temperature distribution, and systematically study the packaging structure of white LED, and propose a packaging structure to improve the uniformity of color temperature distribution of white LED. On the basis of simulation, the experimental results show that the new packaging structure can effectively improve the uniformity of color temperature distribution of white LED. Firstly, the physical model of white LED is established. The physical models include the MQWsN multiple quantum wells model of blue LED, the structure model of phosphor layer, the boundary model, the calculation model of color temperature and the transmission model of white LED. The optical properties of white LED are simulated by Monte Carlo method. Based on the light intensity adaptive packaging structure, a novel surface packaging optimization structure based on light intensity adaptive is proposed. The optimized structure consists of two layers: the light intensity adaptive layer and the traditional dot glue layer. The first layer is the light intensity adaptive layer and the second layer is the traditional dot glue layer. The simulation results show that the optimized structure is superior to the light intensity adaptive structure in color temperature uniformity. Through simulation and experiment, it is found that the color temperature uniformity of the optimized structure is better than that of the light intensity adaptive structure. When the average color temperature is about 5200K, the ACU of the optimized structure increases 7.85 and the luminous efficiency increases by 33.3than that of the adaptive light intensity structure. The optimized structure is compared with the packaging structure coated with silica gel layer on the light intensity adaptive layer. The spatial color temperature uniformity of the optimized structure is better, and the luminous efficiency increases by 12.2 when the average color temperature is 4900K. Then, the effects of different process and structure parameters on the optimization of structure performance are studied. The influence of the adaptive layer thickness on the optical properties of the new structure was studied by comparing the change of the thickness of the adaptive layer with the concentration change of the traditional dispenser. The optimized structure with improved process and structure parameters is obtained. The exposure current exposure of 1 A is used. The concentration of the traditional colloidal layer is 1: 9. When the average color temperature is 5500K, The spatial color temperature standard deviation of the optimized structure is 75K, the luminescence efficiency is 92.1 Wlm / s, the spatial color temperature standard deviation of the adaptive structure is 195K, the luminescence efficiency is 68.5 Wlm / r, and the spatial color temperature standard deviation of the self-adaptive structure is 135K, and the luminescence efficiency is 83.9 Wlm / r. The standard deviation of space color temperature decreased by 61.5% and 44.4%, and the luminous efficiency increased by 34.4% and 9.7%, respectively. The color temperature uniformity of the optimized structure is improved, and the efficiency is improved compared with the adaptive structure. Finally, the encapsulation structure based on free-form surface lens is designed by using edge ray theory and energy conservation theorem. Monte Carlo simulation shows that the spatial color temperature distribution is uniform. When the color temperature is 5200K, the ACUU Angular Color Uniformity is greater than 0.98, and the maximum color temperature difference is 107K.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TN312.8

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