Hexagonal microlens array fabricated by direct laser writing and inductively coupled plasma etching on organic light emitting devices to enhance the outcoupling efficiency

Abstract

A hexagonal microlens array directly fabricated on an indium tin oxide glass substrate by the combination of direct laser writing and inductively coupled plasma etching is demonstrated to enhance the outcoupling efficiency of the organic light emitting devices, which can avoid the loss of photons and the mechanical and thermal deformations at the glass/microlenses interface. An atomic force microscope measurement indicates the contour of the fabricated hexagonal microlens is nearly an ideal part of a hemisphere. From the comparison with the operating OLED without a microlens array, the outcoupling efficiency is enhanced more than 40% with the hexagonal microlens array on the glass substrate, and the enhanced emission from the active area of the device with the hexagonal microlens array at the viewing angles from 0 degrees to 40 degrees can clearly be seen.