The Virtual Retinal Display they’ve developed has no screen – it actually projects images directly onto your retinas, which gives it a number of advantages over LCD-based headsets.
For starters, the image quality is reportedly much better. The goggles use an advanced micromirror array to beam two separate WXGA (1,280×768-pixel resolution) images at each eye, which is essentially double the effective resolution of currently-available Oculus Rift developer kits. Additionally, since these images are being generated with reflected rather than emitted light, they more accurately mimic the way we see in the real world. Pixels blend together more naturally this way, and, since there’s no screen anywhere, the wearer won’t experience the dreaded “screen door effect” that generally occurs when LCD’s or OLEDs are placed close to the eye.