螢光粉噴塗白光發光二極體製程與特性研究

Abstract

本論文主要探討發光二極體螢光粉噴塗技術穩定性之改善及解決傳統點膠在白光發光二極體光學與色彩不均勻的問題。 首先，針對噴塗技術穩定性做主要影響因子研究，並找出合適製程參數範圍，進而改善噴塗穩定性。其次，傳統LED封裝普遍有空間色彩不均勻的現象存在，本論文提出使用脈衝式噴塗螢光粉技術，搭配合適擴散粒子在發光二極體晶片表面噴塗分層結構，可有效提升出光效率與改善色彩均勻度。 由本論文研究結果顯示，噴槍針閥磨耗次數對設備噴塗穩定性有顯著的影響。此外，噴塗的氣壓時序控制與噴塗氣壓反應時間亦是影響噴塗穩定性之主要影響因子。藉由製程參數之修正，可使噴塗穩定性由 ± 20%改善為 ± 5%。另外，本論文使用脈衝式多層噴塗發光二極體的方式，使螢光粉可均勻塗佈於發光二極體的外圍，再搭配氧化鋯奈米粒子擴散劑的使用，可明顯改善白光發光二極體黃圈現象且對於白光發光二極體之發光效率亦有效提升。

This thesis is focused on the process stability improvement for light-emitting diode phosphor spray technology. The purpose is to provide a coating method for uniform phosphor coated layers and the solution for enhancing the angular correlated color temperature (CCT). The main findings of this study are (1) the needle worn-out time is one of the key factors determining the spray coating stability, the control of time interval and the pressure response time. With the optimization of the needle manipulation, we successfully achieve the coating stability within ± 5% from ± 20% error; (2) the uniform phosphor coated layers on the chip surface can be achieved with pulse mode spray technology; (3) The ZrO2 nano-particles sprayed on top of phosphor layer resulting multi-layer structure achieve the higher lumen output and the better angular CCT than those coated by the conventional dispensing method. This study offers a promising result for conserving the phosphor as well as replacing the traditional process.