Understanding Waveguide: the Key Technology for Augmented Reality Near-eye Display (Part I) (anybody remember Scoble's Facebook Interview with Lumus Founders in which they say "we could be using OLED now", right near the end..

1. Optical Waveguide — Born on Demand

The optical system is usually comprised of a microdisplay and imaging optics, for both VR and AR near-eye displays (NED). A microdisplay provides the image either actively like in micro OLED or the trendy micro LED panel, or indirectly by illuminating light on liquid-crystal based display (including transmissive LCD, and reflective LCOS), and digital micromirror device (DMD) as well as laser beam scanner (LBS) both enabled by microelectromechanical system (MEMS). 

https://virtualrealitypop.com/understanding-waveguide-the-key-technology-for-augmented-reality-near-eye-display-part-i-2b16b61f4bae