Light Extraction Layer (IEL / EEL)
OLED panels may include two light extraction layers, known as the Internal Extraction Later (IEL) and External Extraction Layer (EEL). Both layers are used to increase the efficiency of an OLED panel by allowing additional light to escape the panel. IEL and EEL do this by acting as a sort of stepping stone between different layers by reducing the difference of the index of refraction (a way to describe the speed of light through a material) between them.
OLEDs may have any combination of no extraction layer, IEL only, EEL only, or both IEL and EEL depending on efficiency requirements and desired aesthetic.« Back to Glossary Index