含氟化物荧光粉白光LED封装应用高温高湿失效机理及解决方案研究

Study on Failure and Its Solution of White LED Containing Fluoride Phosphor after High Temperature and High Humidity Reliability Test

分析了含氟化物荧光粉LED灯珠高温高湿存储光通量维持率异常的原因,并研究了氟化物荧光粉的耐水稳定性。结果表明,可靠性异常的原因是水汽在长期的高温高湿试验中从灯珠封装胶面和支架底部渗透进荧光胶中,并与氟化物荧光粉发生水解反应,Mn^(4+)浓度和颗粒结晶度下降,发光效率降低,并生成了吸光严重的棕色MnO_(2)。提出一种改善的封装方法并进行了实验验证。实验结果表明,采用这种方法可以避免氟化物荧光粉被水解,从而提升存储试验后的光通量维持率。

The reasons for abnormal luminous flux maintenance of white LED containing fluoride phosphor after high temperature and high humidity reliability test and water resistance stability of fluoride phosphors were studied.The results show that during a long-term high temperature and high humidity test,water vapor infiltrated into the fluorescent adhesive from the top and bottom of the LED package and underwent a hydrolysis reaction with fluoride phosphors,leading to a decrease in the concentration of Mn^(4+) and particle crystallinity of fluoride phosphors,resulting in a decrease in luminous efficiency,and the formation of brown MnO_(2),with light absorption.A novel method of packaging was proposed and verified by experiments.The results show that this method can avoid hydrolysis of fluoride phosphor,thereby improving the luminous flux maintenance rate after storage testing.