Researchers Develop 'Artificial Eyelid' That Reacts Faster Than A Laser

March 17, 2000

GAINESVILLE, Fla. — Researchers at the University of Florida and a North Carolina institute have invented a chip-like device with a surface that turns from transparent to opaque so rapidly it can shield the eye or electronic sensors from potentially blinding lasers.

While the primary application of the “artificial eyelid” is military, consumer applications may range from programmable sunglasses to better cameras, said Paul Holloway, a UF professor of materials science and engineering and one of the researchers on the project.

“There are a whole host of applications,” Holloway said.

Holloway and his colleagues at the UF College of Engineering and a non-profit North Carolina-based technology institute have successfully demonstrated prototypes of the device, which uses extremely tiny polymer and electrode films to control transmission of light. Part of the fast emerging field of nanotechnology — the creation of machines so small they can only be viewed with a powerful microscope — the eyelid is intended to protect military pilots and equipment from disabling laser attacks.

Holloway and other researchers in UF’s department of materials science and engineering contributed to the eyelid as part of research for the Defense Advanced Research Projects Agency, or DARPA, and Army Research Office. Holloway presented the team’s findings this month at a conference of the International Society for Optical Engineering.

While largely seen as a future threat, contemporary reports of laser attacks are not unprecedented. A U.S. Navy officer and a Canadian military pilot say they were flashed by a laser while photographing a Russian cargo ship off the coast of Washington state in 1997. Although the Pentagon says there is no proof a laser was involved, the two officers have suffered recurring pain that doctors have tied to laser exposure, say news accounts.

In an era when satellites are on the front lines of defense, lasers pose a big threat to national security, Holloway said.

“We rely a lot now in terms of our defense systems on overhead satellites,” he said. “These satellites typically have high-power, high-resolution cameras. If somebody wants to avoid them, they can take a ground-based laser, point it up and knock out the cameras.”

To counter the threat, Holloway and the other researchers used chip-making techniques and materials to design and build a device that contains thousands of tiny apertures — apertures that can range in size from about a millimeter to 50 micrometers (there are 25,400 micrometers in an inch). Tests of prototypes showed the apertures can open and close as many as 10,000 times in one second. When deployed, say, on a satellite camera, a tiny sensor would detect the laser, shut down the apertures and protect the camera. Although prototype eyelids up to now have been mounted on an opaque silicon base, prototypes under development are mounted on glass, ideal for optical sensors.

The device has several potential consumer applications, Holloway said. For example, sunglasses now on the market that adjust to changing light conditions use a photochromic process that may require several minutes to complete the adjustment. Sunglasses with the eyelid technology, by contrast, would adjust instantly through opening the appropriate number of apertures for the light hitting the glasses, he said.

The sunglasses, which could be powered by a small battery encased in the frame, also could handle more extreme situations, such as eclipses, he said.

“If I wanted to watch the solar eclipse, for example, I could put on my smart glasses, and they would automatically block out the sun and I would only see the corona,” he said.

Cameras also could benefit. For example, the eyelid technology could be installed in home video cameras to eliminate the common problem in videotapes of a bright light darkening the content of the surrounding frame, Holloway said.

DARPA has provided about $500,000 for the research, part of more than $9 million the agency has committed for Holloway’s research at the Center for Materials in Sensors and Actuators, or MINSA. The other UF faculty members involved in the research are Tony Brennan, Elliot Douglass, Joseph Simmons and Wolfgang Sigmund. Besides the North Carolina institute, MCNC in Research Triangle Park, engineers from Clemson University, Pacific Northwest National Laboratory and Lockheed-Martin in Orlando are involved.