基于紫外激发荧光玻璃的白光LED封装技术研究

Currently, the development of high-efficiency and high-quality white light-emitting diode (WLED) devices is a key technology for high-power LED packaging. Ultraviolet (UV)-excited WLED is an important approach to obtain high-quality white light. However, it has the problems of low light efficiency and poor reliability. Based on our previous researches about LED packaging and phosphor-in-glass (PiG) preparation, the UV-excited WLED packaging technology based on red, green, and blue (RGB) PiG was proposed to solve the problems of UV-excited WLED packaging. The research contents include: 1) The mechanisms of photon transportation and interface scattering in the PiG were revealed through Mie scattering theory and ray tracing method, and the corresponding photon transportation models of PiG were established. The effects of internal pores and phosphor particles on the transmittance of PiG were investigated. 2) The RGB PiGs were fabricated by screen-printing combined with low-temperature sintering technique. The influence laws of multi-layered phosphor structure on the light efficiency of PiG-based WLED were studied. The transmittance of PiG was enhanced and the light scattering and reabsorption losses were reduced by process optimization. 3) The packaging experiments of UV-excited WLEDs were carried out and their performances were measured, and then the PiG preparation and the packaging technology were optimized. This proposal explores new ideas for developing high-power WLED devices, which promotes the development of semiconductor lighting technology.

研发高光效、高品质白光LED器件是目前大功率LED封装技术的关键，紫外激发白光LED是获得高品质白光的一种重要途径，但存在出光效率低和可靠性差等问题。项目在前期LED封装技术和荧光玻璃制备研究的基础上，提出基于三基色荧光玻璃的紫外激发白光LED封装制造技术，以解决紫外激发白光LED封装技术难题。研究内容包括：1）结合米氏散射理论和光线追迹法，揭示荧光玻璃中光子传输与界面散射机理，建立荧光玻璃光子传输模型，探讨气孔和荧光粉颗粒对荧光玻璃透光率的影响；2）采用丝网印刷结合低温烧结技术制备三基色荧光玻璃，研究分层荧光结构对LED出光效率的影响规律，并通过工艺优化提高荧光玻璃透光率，以及降低光散射和重吸收损耗；3）开展紫外激发白光LED封装实验和测试评价，优化荧光玻璃制备和封装技术。项目实施为大功率白光LED器件研发开辟了新思路，对促进半导体照明技术发展具有推动作用。

随着人们对光色品质、照明舒适度的需求不断增加，实现高光效、高品质白光LED器件是目前大功率LED封装技术的关键，以营造舒适健康的光环境。目前，紫外激发三基色荧光粉是获得高品质白光LED的一种重要途径，但存在出光效率低、可靠性差等问题。项目提出了紫外激发荧光玻璃的白光LED封装技术，构建了高性能荧光玻璃，提高了白光LED发光性能和可靠性，解决了紫外激发白光LED封装技术难题。具体内容包括：建立了荧光玻璃光子传输模型，分析了气孔大小和孔隙率、基质玻璃折射率和荧光粉折射率对光散射的影响，获得了提高荧光玻璃透光率的有效方法；采用丝网印刷与低温烧结工艺制备了三基色荧光玻璃，通过高折射率基质玻璃降低了荧光粉颗粒散射损耗，采用分层堆叠结构降低了光谱重吸收损耗，利用蛾眼化微结构抑制了表面全反射损耗，提高了白光LED出光效率；构建了宽频带荧光玻璃，弥补了青色光谱间隙并实现全光谱白光（Ra=95.4、R9=95.1和R13=97.3），且采用堆叠量子点薄膜和集成量子点溶液的方法提高了白光LED显色性；制备了高导热荧光玻璃，利用高效导热网络提高了荧光层热耗散，降低了工作温度（小于100℃）；开发了全无机荧光玻璃封装工艺，分析了封装结构对白光LED光热性能的影响，得到了高可靠白光LED器件；提出了荧光玻璃芯片级白光LED封装方法，制备了晶圆级荧光玻璃片，提高了白光LED光热性能；对比分析了荧光玻璃封装与荧光胶封装热稳定性，荧光玻璃降低了白光LED65%光效衰减，提高了白光LED长期可靠性。基于本项目，取得了一系列原创性的成果，以第一或通讯作者发表期刊论文19篇（ESI高被引论文2篇、封面论文2篇），申请发明专利7项（授权4项），并与相关企业建立深度合作关系，大力推广紫外激发白光LED产品。项目的实施为大功率白光LED研发开辟了新思路，对促进半导体照明发展具有重要推动作用。