A labeled photo shows the LED, antenna, and integrated circuit embedded in a plastic contact lens.Babak Parviz/J. Micromech. Microeng
Cyborgs of the future beware: Humans are working on computerized contact lenses with display technology.
"Some day maybe we'll have full-fledged streaming in your contact lenses," said Babak Amir Parviz, an associate professor of electrical engineering at the University of Washington who co-authored a paper describing the computerized new contact lens in the latest issue of the Journal of Micromechanics and Microengineering.
Parviz along with an international team of engineers has constructed a contact lens embedded with a tiny LED that can light up when a wireless signal is sent to it.
Parviz collaborated on the device with UW ophthalmologist Tueng Shen and researchers from Aalto University in Finland led by optoelectronics professor Markku Sopanen. Parviz's group specializes in incorporating miniaturized devices into unconventional materials and has been working on functional contact lenses for a while, he said.
"If we can make very small devices of various sorts, if we have the ability to put them into different materials, what can I do with this contact lens that I stare at every morning?"
The engineers took an extremely small custom-designed LED made with sapphire and embedded it in the center of a plastic contact lens. They also embedded a circular antenna around the inside lip of the lens. A miniature integrated circuit connects the antenna and the blue LED. Using remote radio frequency transmission, the group was able to control a single pixel.
With this setup, a human eye still wouldn't be able to distinguish that pixel due to the minimum focal distance required to see anything clearly. With that in mind, the researchers created a separate, non-computerized contact lens containing an array of special flatter, thinner lenses known as Fresnel lenses, each less than a micron thick. The array successfully focused light from the LED.
Once the researchers had determined that the experimental lenses were safe in the lab, they tested them on live rabbits. After wearing them for a short period, the rabbits didn't have any abrasions or thermal burning. "We have been able to build the whole system and test it on rabbits, on live eyes, and show that this works and it's safe," Parviz said.
Being able to display information and images directly into the field of vision via contact lens would be useful in a number of ways, according to the engineers. The devices could be used for navigation, for gaming, and even as a way to monitor someone's health and safety. It could also be a super sneaky way to access info while carrying on a conversation.
This early system is still extremely rudimentary, Parviz said. The computerized lens is made from polyethylene terephthalate (PET), a hard plastic that doesn't allow airflow to the eye, limiting usage to only a few minutes. Although the device could be powered from about three feet away when outside the eye, that distance narrowed to about an inch when the contact was in an actual eye. While a single pixel lighting up could potentially be useful as a warning, without the focusing micro-lenses, the rabbits only saw a blurry shadow.
The researchers are planning to tackle these challenges. They are working on combining the flat micro-lens technology that can focus light with the computerized device in the lab. They would like to increase the pixel count, refine the antenna design, widen the wireless range, and get the components into a softer, more flexible material.
"If we can make them as comfortable as normal contact lenses, you don't feel you're wearing them," Parviz said. Contacts would allow users to take their displays with them anywhere, hands and headset-free, he added. "In a sense, it's the ultimate electronic gear that is totally unnoticeable."
Arnaud Bertsch is a microsystems researcher at the École Polytechnique Fédérale de Lausanne (EPFL) in Switzerland who previously worked on incorporating sensors into a soft contact lens for glaucoma detection. That project resulted in a commercial product now sold by the Swiss company Sensimed.
"There's still a little more integration to do to have something that can be used as a device for projecting an image onto the retina, but basically the concept is here," he said of the new contact lens.
Bertsch thinks that it could take 10 years to achieve fully functional computerized contact lens displays, but added that the field has taken big steps forward with help from miniaturization.
"Five years ago, it was something like science fiction. When we started to discuss integrating things into a contact lens, people were laughing," he said. "Now it's real."