Image: University of WashingtonMany years ago a friend of mine turned up at our house with a new toy. It was basically a combat game and came complete with head-piece, vest and gun for each of 4 players. The gun “fired” some sort of signal – presumably infra-red – which was detected by sensors on the back, front and shoulders of the vest. As the number of shots inflicted upon you increased, you became more “injured” and eventually dead, just like in countless video games.

We proceeded to run about a local park hiding behind play equipment, hillocks and public toilets and taking shots at each other whenever we could. Other people in the park seemed rather bewildered as we ran, stumbled and giggled our way around them. We were in our twenties and I can only imagine what people thought when they emerged from the public toilet to come face to face with a young man in red goggles holding a gun.

I only remember playing this game once and I don’t think any of us were very good at it, possibly because we were distracted by the cool-ness of the head-up display in the head-piece. It was by this display that each player knew how dead they were becoming and what the team scores were.

Since then (and with added input from various science fiction movies) I have had a special place in my heart (and possibly corneas) for head-up displays. I have been quietly looking forward to the day when mobile phones and perhaps laptops could have their screens replaced by some sort of tiny virtual display. That day is a step closer with the announcement by Babak Parviz and his team at the University of Washington of a new contact lens embedded/imprinted with visual display circuitry. The idea is to produce images that appear to float between 50 cm and 1 metre in front of the user.

They have managed to develop flexible, biologically safe contact lens with an imprinted electronic circuit and tiny LEDs. The circuitry was built using microfabrication self-assembly techniques in which a mixture of various particles is dusted onto a sheet of flexible plastic. Shape-complementarity causes these particles to aggregate into desired structures – in this case the various components of the circuit.

Currently the challenge of powering the lens is met by an antenna that picks up power beamed from a nearby radio source, but the plan is to use from the user's mobile phone.

At present the display is very simple, but as a proof pf principle it’s pretty exciting. Such displays could be used to display speed and performance information for drivers and pilots, to provide information for the visually impaired and of course for gaming. Then there’s web surfing, email, texting, over-laid car navigation systems, sub-titles at the opera . . .