基于高压倒装LED芯片的光源制作与热特性分析

发布时间：2018-04-30 18:56

  本文选题：高压倒装芯片 + COB光源　； 参考：《深圳大学》2017年硕士论文

【摘要】：近年来LED(light emitting diode)在照明领域中的应用逐渐得到普及,人们对LED提出更小体积、更高亮度、更高功率的要求,这种高功率、高集成度的发展趋势给芯片及封装行业带来商机的同时,也让芯片及封装行业面临越来越大的挑战,其中散热问题最为引人关注。散热不畅导致LED热量聚集,引起芯片结温增大,而结温过高会引起波长红移,造成发光不均匀、发光效率下降甚至烧毁失效等危害。所以探讨如何提高LED照明的散热能力是具有很强的现实意义。解决散热的方案都应从先进的封装技术及材料上入手,如使用导热性能更好的陶瓷基板,降低焊接层空洞率,封装基板表面材质与固晶材料的匹配选择等等,都能在一定程度上提高LED的散热能力。本文使用普通2835 LED器件制作了电视背光源、使用高压倒装LED芯片制作了集成化照明光引擎,并研究了他们的散热问题。本文的主要工作可分为两部分:(一)光源制作:使用2835 LED制作了电视背光源组件,使用高压倒装LED芯片制作了COB(chip on the board)集成化筒灯光引擎,也采用PFC技术制作了高压的PFC-LED器件,并用其制作了相应的光源组件;(二)数据测试及分析:利用积分球、热阻分析仪以及ANSYS仿真软件对所制作的光源进行测试分析。主要研究结果如下:第一、研究焊接层空洞率对LED背光照明组件热性能的影响,结果表明:焊接层空洞率增大,样品结温与热阻都明显增大,基本呈线性增长趋势。当空洞率约为17%时,热阻增长6.03%,结温增长1.74%;当空洞率约为73%时,热阻增长24.7%,结温增长9%。第二、制作了高压倒装及常压倒装两款COB光源,并测试了光源的热阻参数。与市场上的普通筒灯光源热参数对比结果为:同功率的光源,普通COB光源的结温为48.6℃,倒装COB光源的结温为38.83℃,降低了20%;这表明使用倒装芯片可以有效的降低LED照明组件的结温,而且能降低光源集成度,减少成本投入。第三、研究了新型高压倒装PFC-LED(package free chip LED)照明组件的热性能,测试结果显示9V高压倒装PFC-LED器件的热阻约为0.342 K/W,近似等于LED芯片的热阻,远低于同等电压下正装LED芯片的热阻(约3.5K/W)。本论文使用高压倒装LED芯片,制作了两款可替代市场上现有筒灯光源的倒装光源,具有使用芯片数量少、尺寸小且轻薄、便于集成、无需金线键合等优点。高压倒装LED芯片减少了成本、降低了COB光源的尺寸;其次,从封装工艺上,不仅缩短了散热通道,而且散热路径向下,更有利于冷却设计,又可以直接焊接在印刷有电路的基板上,避免进行二次封装,更有利于散热;同时提高了可靠性,倒装芯片无需用金线进行电气连接,避免了焊点脱开造成的可靠性问题,简化了封装工艺。最后对制作的光源进行了相关的光热测试分析,为高压倒装LED芯片的封装及应用提供了热学设计依据。
[Abstract]:In recent years, the application of LED(light emitting in the field of lighting has been gradually popularized, people put forward the requirement of smaller volume, higher brightness and higher power for LED. This development trend of high power and high integration brings business opportunities to the chip and packaging industry. Chip and packaging industry is also facing increasing challenges, among which the issue of heat dissipation most attention. Poor heat dissipation leads to the accumulation of LED heat, which results in the increase of chip junction temperature, and the excessive junction temperature will lead to the red shift of wavelength, resulting in non-uniformity of luminescence, the decrease of luminous efficiency and even the failure of burning out and so on. Therefore, it is of great practical significance to discuss how to improve the heat dissipation ability of LED lighting. The solution to heat dissipation should be based on advanced packaging technology and materials, such as the use of ceramic substrate with better thermal conductivity, the reduction of voids in welding layer, the matching selection of surface materials and solid crystal materials, etc. Both can improve the heat dissipation ability of LED to a certain extent. In this paper, 2835 LED device is used to fabricate TV backlight source, and high voltage inverted LED chip is used to fabricate integrated lighting engine, and their heat dissipation problem is studied. The main work of this paper can be divided into two parts: the backlight module of TV is made with 2835 LED, the integrated tube lighting engine of COB(chip on the board) is made by using high-voltage inverted LED chip, and the high-voltage PFC-LED device is made by PFC technology. The corresponding light source components (2) data test and analysis are made. The light source is tested and analyzed by integrating sphere, thermal resistance analyzer and ANSYS simulation software. The main results are as follows: first, the effect of welding layer voids on the thermal performance of LED backlight lighting assembly is studied. The results show that the weld layer voids ratio increases, the junction temperature and thermal resistance increase obviously, and the growth trend is linear. When the void rate is about 17, the thermal resistance increases 6.03, the junction temperature increases 1.74; when the cavity rate is about 73, the thermal resistance increases 24.7and the knot temperature increases 9. Secondly, two COB light sources, high pressure inversion and atmospheric pressure inversion, are made, and the thermal resistance parameters of the light source are tested. The results are as follows: the junction temperature of ordinary COB light source is 48.6 鈩，

本文编号：1825768