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Scientists develop an in-eye display

The dawn of true hands-free smartphone use could finally be upon us, as scientists complete in vivo testing of a wirelessly-powered display system built into a contact lens.

A team of Finnish and US scientists, led by the University of Washington's Babak Praviz, are paving the way to a future whereby traditional display devices are done away with entirely in favour of military-style head-up display systems built into contact lenses.

Granted, the team has a long way to go before you can start reading your emails or playing Quake whilst staring blankly into space: the prototype system, which has completed in vivo testing on rabbits ahead of planned human trials, offers just one single pixel of resolution.

For the record, that resolution is 153,000 times lower than the average smartphone display and 2,073,600 times lower than a Full HD - 1920x1080 - TV screen.

The purpose of the experiment isn't to provide bunnies with a built-in entertainment system, however, but to prove that it's possible to provide a signal and - crucially - power to components located on the surface of a contact lens, something which the team has demonstrated admirably.

In a submission to the Journal of Micromechanics and Microengineering, the team describes the device thus: "The display consists of an antenna, a 500×500µm² silicon power harvesting and radio integrated circuit, metal interconnects, insulation layers and a 750×750µm² transparent sapphire chip containing a custom-designed micro-light emitting diode with peak emission at 475nm, all integrated onto a contact lens."

Experimentation has shown that the display system can be powered completely wirelessly - a requirement for something you stick in your eye - from around a metre distance in free space, although this drops significantly to around 2cm in vivo.

The rabbits - which were under anaesthetic to prevent undue stress - showed no ill effects from the use of the display.

The team is now working on the development of a multi-pixel display featuring micro-Fresnel lenses to 'project' more detailed images onto the retina, but admit that the technology is quite some way from commercialisation.

The team's full paper on the technology can be read over on the Institute of Physics' IOPscience site (opens in new tab) (free registration required.) monitors all leading technology stories and rounds them up to help you save time hunting them down.