Researchers from the University of Washington in the United States and Aalto University in Finland have created a contact lens with an electronic display, which at this stage contains a single pixel. The lens also includes an antenna for receiving power from an external radio transmitter, and an integrated circuit to store this energy and transfer it to a tiny LED chip.

The scientists say that once this technology is further developed, such a contact lens could be used to overlay computer-generated texts and graphics on the real world, allowing its wearer to, for example, read e-mails without having to look at a screen, or as part of a video game system or a future navigation-type device.

Tested for comfort

In a study published in the Tuesday edition of the Journal of Micromechanics and Microengineering, the researchers reported on the tests they carried out in free space and on lab rabbits.

The lenses that were placed on rabbits' eyes appeared to work well - and there were no signs of damage or abrasions to the eyes after they were removed.

This new finding represents the latest step in years of research into augmented reality-style contact lenses.

"Of course there are some foreign materials in the lens, but they are sealed well, so they shouldn't be dangerous," said Markku Sopanen, a professor of optoelectronics at Aalto University, in an interview with Deutsche Welle.

Sopanen's team, together with Aalto University's Nanotechnology Department, is responsible for developing LED chips for the lenses. The chips are roughly 500 micrometers (half a millimeter) by 500 micrometers in size.

"Our LED chips are definitely robust, so they don't present a physical danger," added Sopanen.

Room for improvement

One major hurdle in developing the technology is the fact that the human eye - which has a minimum focal distance of several inches - would normally only see blurry images on a contact lens.

To overcome this, the contact lens was produced as a Fresnel lens - in which a series of concentric annular sections is used to generate the short focal length needed.

The developers' vision is to produce lenses with multiple pixels which could display more complex images. Lenses of this kind could also be connected to biosensors in the body to help detect levels of various components, such as glucose, in the blood.

"The LED chip itself isn't too difficult to make - it's quite standard technology that we just have to adjust a bit," said Sopanen. "It's all about how closely the electrical conducts can be placed."

The Finnish team has been working on the project since 2009, when they were approached by Babak Parviz of the University of Washington, who initiated the research.

"We need to improve the antenna design and the associated matching network and optimize the transmission frequency to achieve an overall improvement in the range of wireless power transmission," said Parviz in statement published by the university. "Our next goal, however, is to incorporate some predetermined text in the contact lens."

The team hopes that these new contact lenses could soon provide some sort of pop-up display, not unlike what is shown in the "Terminator" series of science fiction movies.

"One day, if you can form real images, like computer images, the applications of this technology will of course be much wider," said Sopanen. "Then, our only limit will be our imagination."

Author: Eva Wutke
Editor: Cyrus Farivar