具有黑矩陣之有機發光二極體的效率提升之研究

Abstract

有機發光二極體(Organic Light-Emitting Diode, OLED)在顯示技術上比起目前廣泛被應用的薄膜電晶體液晶顯示器可達到更快的反應速度、可藉由更廣的色域來大幅提高影像品質，並且可製作於軟性基板上的特性也增加了對於顯示器應用範圍的想像空間。OLED更具有可調節色溫、高演色性及面光源等特性，在顯示及照明技術未來的發展上將會占據十分重要的地位。 但由於OLED結構為不同材料層狀堆疊，而各層間的折射率差使得大部分的光線因全反射的機制被困在結構之中，造成出光效率不佳及壽命不高的問題。一般而言常使用微透鏡陣列薄膜(MAFLs)來破壞玻璃基板以及空氣介面間的全反射，將困在玻璃基板內部的光線耦合到結構之外。 OLED應用於顯示器的情況下，會使用黑矩陣來降低環境光造成的對比度低落，但黑矩陣會大幅降低微透鏡耦合出光的增益造成外部量子效率降低。在本論文中，我們透過研究微透鏡出光機制的研究，找出黑矩陣對微透鏡增益影響的成因，並且提出提高開口率、黑矩陣鍍反射膜、降低填充層厚度及降低玻璃基板厚度等四種改善黑矩陣對微透鏡影響的方式，最高可以在不加填充層並且將黑矩陣背面鍍上反射膜的情況下得到54.17%的增益。

Organic Light-Emitting Diode (OLED) can achieve a shorter response time and better color quality than Thin-Film-Transistor Liquid Crystal Display (TFT-LCD), the mostly used display technology recently. Furthermore, OLED displays have the advantage of being made on flexible substrate. Also, the high color rendering index, the adjustable color temperature, and the surface emitting source makes OLED important in both the display and lighting industry in the future. The biggest confrontation of OLED is that its multi-layer structure and large amount of the light emitted from the organic layer will be trapped within the layers by total internal reflection (TIR). Micro-lens array films (MAFs) is used solve the problem. It breaks down the TIR between glass substrate and the air. Black matrix (BM) layer is normally used to reduce the ambient light when using OLED structure, which might cause a significant drop in the contrast ratio. The BM layer, however reduce the light out-coupling efficiency in a very effective way. Through examinations, we studied the light out-coupling improvement mechanism of the MAFs, and found out why the BM layer causes such a huge difference. In this study, we also give out four possible optimizations on the OLED structure to avoid the trade-off between BM and MAFs.