MIT scientists have created a transparent screen using silver nanoparticles for an augmented reality display that places digital images over the real world.
Wearable HUD Google Glass is not an augmented reality device. Rather, it's a screen in your field of vision. The prism that overlays the world with interactive digital images is too thick and too small to cover your full field of view, as with a true augmented reality device.
In fact, producing such a device is proving difficult. Although devices are attempting it, such as Laster's SeeThru, the Vuzix M100 and the Meta Space Glasses, they all face similar screen size and thickness limitations.