摘要
为实现蓝光LED(LAght emitting diode)芯片向白光LED照明的转化,大功率LED封装工艺流程中存在一个关键的环节——荧光粉涂覆,即通过点涂方式将荧光粉硅胶涂覆于LED芯片周围.荧光粉硅胶涂覆工艺是一个两相流动过程,它直接决定了荧光粉硅胶层的几何形貌及物理特性,并影响LED最终的光学和热学性能;因此对其中流动过程物理机制的理解有利于提升荧光粉涂覆质量,实现高性能LED产品。基于以高速摄像机为核心的光学实验平台,对荧光粉硅胶在平坦基板表面涂覆流动铺展过程的形貌进行了捕捉,并研究了涂覆高度、荧光粉浓度和基板表面温度对流动过程的影响.实验结果表明,依据相对铺展速度的变化特性可以将荧光粉涂覆流动过程分为撞击阶段、铺展阶段和稳定成形阶段;涂覆高度、荧光粉浓度、基板表面温度的改变会对流动铺展不同阶段的接触线长度和相对铺展速度dL/(D·dt)造成影响,基板温度的改变还会影响到最终接触线长度。
For the realization of the transformation from blue Light LED chip to the white LED lighting,phosphor silicone coating process is an important process.This process is a typical two phase flow,which directly determines the geometry and physical properties of the phosphor layer,and affects the optical and thermal properties of LED.Therefore it is important to understand the wetting and spreading behaviors in the coating process for improving the phosphor coating quality as well as the LED performance.An experiment platform based on high speed camera was applied to capture the morphology of phosphor gel during wetting and spreading process,coating height,phosphor concentration and substrate temperature were studied through experiments respectively.Results show that the phosphor spreading process can be divided into three stages,collision stage,speeding stage,stable forming stage,respectively.According to the spreading velocity difference,dynamic contact line and relative spreading velocity dL/(D · dt) change with coating height,phosphor concentration and substrate temperature.Besides,substrate temperature also affects the final contact line length.
出处
《工程热物理学报》
EI
CAS
CSCD
北大核心
2015年第5期1096-1100,共5页
Journal of Engineering Thermophysics
基金
国家自然科学基金(No.51376070)
关键词
荧光粉涂覆
流动铺展
接触线
相对铺展速度
phosphor coating
wetting and spreading
contact line
relative spreading velocity
