讨论了反射镜反射率对LED光提取效率的影响, 并基于芯片与封装协同设计的原理, 针对蓝光和黄光波段, 通过TFcalc膜系仿真软件设计和优化了分布式布拉格反射镜(DBR)膜系。仿真结果表明, 单堆栈DBR结构最大反射带宽为134nm, 而双堆栈DBR结构最大反射带宽可拓展至216nm。利用参考波长红移的方式, 可以缓解DBR反射特性随入射角度增加而出现的反射谱线蓝移现象。金属增强型DBR结构能够减小反射偏振效应, 提高反射带宽和平均反射率, 并能够减小DBR厚度, 从而显著改善芯片的散热性能。

The effects of the reflectivity of reflector on the light extraction efficiency of LED were discussed. Aiming at the blue and yellow light band, distributed Bragg reflectors (DBR) with high reflectivity were designed and optimized with TFcalc simulation software based on collaborative design of the LED chips and packaging. Simulation results show the maximal reflection bandwidth of double-DBR stacks can reach up to 216nm, which is 82nm higher than that of a single-DBR stack. The red shift of reference wavelength can be used to alleviate the blue shift of DBR reflection line arising with the increase of incident angle. The metal-enhanced DBR structure can reduce the reflection polarization effect, increase reflection bandwidth and average reflectivity, and also decrease the DBR thickness, thus optimizing the heat dissipation performance of LED chips.