Combined optical model for micro-structured organic light emitting diodes

Abstract

Organic light emitting diodes (OLEDs) with prospect of low cost, high efficiency and high quality lightning are a promising future light source. Their main limitation is poor light outcoupling, reaching only 20-30 % for conventional flat-plate lighting devices. Optical modelling and simulations are of great importance in optimizing OLEDs optical efficiency. Complex structures of OLEDs, where combination of thin layers with emitting sources and thick texturized substrate layers, require coupled optical modelling approach. We developed a combined optical model, comprising a thin layer stack where light behaves as waves and thick texturized layers where light behaves as rays. This combination enables simulations of OLEDs as a complete device with micro textures. We present the main considerations of the developed model. Finally, an OLED device with laser structured sine textures is used to compare experimental results with simulation results obtained with the developed model.