Augmented reality means quite literally to add something into reality that we don't presently have, and in this context it means adding information. What was previously the exclusive realm of science fiction has recently made a leap in both concept and prototyping, bringing the heads-up-display from video games to within arm's reach.
Essentially a standard contact lens that fits on the surface of the eye in exactly the same way as the visual aids we currently use, these augmented contact lenses fit in wireless power, active or passive displays, control circuits and plenty more. Just like any video game, they can overlay information about the world directly over the world itself, displaying anything from ID tags on supermarket products to travel directions - but how do they work?
Power is delivered to the lens wirelessly, using a form of radio transmission from a transmitter in the user's pocket, which can provide 100µW of electricity. Solar was considered an alternative but the power is significantly lower at only 30µW, and isn't enough to effectively run the systems.
The display itself is built around small LEDs, which are formed into a grid over the pupil, and are actively powered in this prototype due to a passive method proving difficult to design. Both have their upsides, with the former being clear in many situations but the latter using much less power. To allow the eye to focus on something so close to its surface, a series of microlenses within the lens itself change the depth of the LED light.
Control circuits are packed onto a small polymer disc, created individually and embedded in the polymer substrate to be linked by metal circuit traces. The disc is slightly flexible to match the surface of an eye, but rigid enough to hold the components firmly and prevent their breakage.
Already tested to be comfortable with rabbits and other small mammals, human testing isn't too far off down the track. With the possibility of having our information directly transmitted to us wirelessly without having to look at a device specifically suggests a huge amount of freedom, and once the bugs are worked out this system could prove to be the biggest interface revolution since the discovery of the printing press.
Head to ieee spectrum to read more about these contact lenses in depth, and view the image of the prototype below.