含有微透鏡陣列的有機發光元件之分析

Abstract

在本論文中，我們建立了一套演算法，針對微透鏡陣列結構將幾何光學的光 追跡與傳遞矩陣法整合在一起，可同時考慮加了微透鏡陣列的OLED 中的幾何光 學與波動光學特性，並且討論不同的微透鏡陣列結構對於光萃取效率與遠場光形 的影響。我們計算了光線在結構中經過0∼4 次反射的出光效率，發現若只考慮 第一次穿透的話，加入微透鏡陣列以後出光效率的提升相當有限。在結構中來回 反射的光線對於出光效率的提升扮演著重要的角色，特別是經過第一次反射的第 二次穿透光對於出光效率有重要的影響。我們針對三組實際的OLED 結構進行模 擬，找出最高光萃取效率的結構。在我們的模擬結果中光萃取效率有25%∼75% 的提升，遠場的正向光強最大約有25%∼40%的提升。我們發現如果基板中的場 形較集中在正向的話，使用透鏡高度比較低的透鏡可以得到較大的提升。如果基 板中的場形較分散的話，使用透鏡高度比較高的透鏡可以得到較大的提升。

In this thesis, we developed an algorithm which combines transfer matrix method and ray-tracing for the modeling of planar light-emitting devices with microlens array. It can calculate geometrical optics and wave optics characteristics in the LED and OLED simultaneously. We also discussed the effect of microlens array in light extraction efficiency and far field pattern. We calculated the out-coupling efficiency with 0~4 times reflection in structure. The out-coupling enhancement by microlens arrays is very limited when only first transmission is considered. Multiple reflections play critical roles in the enhancement, especially the second out-coupling due to the first reflection. In our simulation, we calculated three groups of actual OLED structures, finding the best structure of microlens array for light extraction efficiency. In our result, light extraction efficiency have 25% to 75% enhancement and normal far field intensity have 25% to 40% enhancement. We found that if the field pattern in substrate is concentrated around normal direction, higher enhancement is obtained from structures with lower height ratio. If the field pattern is dispersed, higher enhancement is obtained from structures with higher height ratio.