Google may be the first company to attempt to turn augmented reality eyewear into a mass-market product, but the concept itself is nothing new. The Augmented World Expo in Santa Clara has collected together more than 30 prototypes of augmented and virtual reality headsets, and Engadget has a comprehensive set of photos which make fascinating viewing.

We’re sharing a few of them below the break, from the crude to the close-to-Glass-like …  expand full story