[tt] Contact lenses with circuits, lights a possible platform for superhuman vision

[Hughes, James J.]

Jan. 17, 2008 | Technology | Science

Contact lenses with circuits, lights a possible platform for superhuman
vision

Hannah Hickey 	   hickeyh at u.washington.edu   	 
University of Washington

Movie characters from the Terminator to the Bionic Woman use bionic eyes
to zoom in on far-off scenes, have useful facts pop into their field of
view, or create virtual crosshairs. Off the screen, virtual displays
have been proposed for more practical purposes -- visual aids to help
vision-impaired people, holographic driving control panels and even as a
way to surf the Web on the go.

The device to make this happen may be familiar. Engineers at the
University of Washington have for the first time used manufacturing
techniques at microscopic scales to combine a flexible, biologically
safe contact lens with an imprinted electronic circuit and lights.

"Looking through a completed lens, you would see what the display is
generating superimposed on the world outside," said Babak Parviz, a UW
assistant professor of electrical engineering. "This is a very small
step toward that goal, but I think it's extremely promising." The
results were presented today at the Institute of Electrical and
Electronics Engineers' international conference on Micro Electro
Mechanical Systems by Harvey Ho, a former graduate student of Parviz's
now working at Sandia National Laboratories in Livermore, Calif. Other
co-authors are Ehsan Saeedi and Samuel Kim in the UW's electrical
engineering department and Tueng Shen in the UW Medical Center's
ophthalmology department.

There are many possible uses for virtual displays. Drivers or pilots
could see a vehicle's speed projected onto the windshield. Video-game
companies could use the contact lenses to completely immerse players in
a virtual world without restricting their range of motion. And for
communications, people on the go could surf the Internet on a midair
virtual display screen that only they would be able to see.

"People may find all sorts of applications for it that we have not
thought about. Our goal is to demonstrate the basic technology and make
sure it works and that it's safe," said Parviz, who heads a
multi-disciplinary UW group that is developing electronics for contact
lenses.

The prototype device contains an electric circuit as well as red
light-emitting diodes for a display, though it does not yet light up.
The lenses were tested on rabbits for up to 20 minutes and the animals
showed no adverse effects.

Ideally, installing or removing the bionic eye would be as easy as
popping a contact lens in or out, and once installed the wearer would
barely know the gadget was there, Parviz said.

Building the lenses was a challenge because materials that are safe for
use in the body, such as the flexible organic materials used in contact
lenses, are delicate. Manufacturing electrical circuits, however,
involves inorganic materials, scorching temperatures and toxic
chemicals. Researchers built the circuits from layers of metal only a
few nanometers thick, about one thousandth the width of a human hair,
and constructed light-emitting diodes one third of a millimeter across.
They then sprinkled the grayish powder of electrical components onto a
sheet of flexible plastic. The shape of each tiny component dictates
which piece it can attach to, a microfabrication technique known as
self-assembly. Capillary forces -- the same type of forces that make
water move up a plant's roots, and that cause the edge of a glass of
water to curve upward -- pull the pieces into position.

The prototype contact lens does not correct the wearer's vision, but the
technique could be used on a corrective lens, Parviz said. And all the
gadgetry won't obstruct a person's view.

"There is a large area outside of the transparent part of the eye that
we can use for placing instrumentation," Parviz said. Future
improvements will add wireless communication to and from the lens. The
researchers hope to power the whole system using a combination of
radio-frequency power and solar cells placed on the lens, Parviz said.

A full-fledged display won't be available for a while, but a version
that has a basic display with just a few pixels could be operational
"fairly quickly," according to Parviz.

The research was funded by the National Science Foundation and a
Technology Gap Innovation Fund from the University of Washington.

###

For more information, contact Parviz at (206) 616-4038 or
babak at ee.washington.edu. During the IEEE meeting Jan. 17-18 reach Parviz
by cell phone at (206) 650-6168.