Holographic Optical Eyewear 

An eyeglass from SBG Labs has a tiny projector in its frame.

EARBUDS can pipe audio directly from a portable player to the ear. But did you ever imagine that eyeglasses or contact lenses could deliver digital images directly from a smartphone to the retina?

Several companies are developing prototypes for digital devices that look like stylish eyewear but may one day offer such capabilities to consumers. The glasses are called heads-up displays because the wearer can always look through them and see the real world – like the sidewalk just ahead – but can also see, on an overlay image, virtual information like an electronic map or an arrow showing the correct way to a destination. The glasses may also help the wearer remember the name of a long-lost friend she sees on the street.

SBG Labs, an optical technology company in Sunnyvale, Calif., is among the businesses that are developing the devices. The glasses are only slightly larger than many chic pairs of wraparounds, but instead of bearing rhinestones or designer initials, they hold a tiny projector and optics – tucked away in the side of the frame.

Such devices may have considerable appeal for consumers, so long as the glasses are attractive and lightweight, said Henry Fuchs, a professor of computer science at the University of North Carolina at Chapel Hill. Professor Fuchs is a pioneer in the creation of precursors to these glasses: large, head-mounted display systems – worn, for example, by soldiers who use them to see information like a map reflected on the visor of a helmet. These displays, though, are typically quite heavy to wear.

“People who work on head-mounted displays are hungering for something that people would be willing to wear for more than an hour,” he said, “something that would go in one’s eyeglasses and not be too much clunkier than regular eyeglasses.”

No price has been set for the SBG eyeglasses, which are still in the prototype stage, said Jonathan Waldern, the company’s founder and chief technology officer. SBG is concentrating on military and avionics applications, with consumer uses to follow.

The technology uses a process called holographic optics. Light-emitting laser diodes in the projector, stored in the side of the frame, shoot their highly concentrated beams forward to the eyeglass surface. There, computerized, transparent devices called holographic gratings diffract light in ways that ordinary optical components like prisms can’t, steering it to the user’s eyes.

Contact lenses are also being developed for mobile displays. Babak A. Parviz, an associate professor of electrical engineering, with his team at the University of Washington in Seattle, has created a biocompatible contact lens that has miniaturized electronics and optoelectronics integrated into the lens.

Dr. Parviz says he is moving a step at a time in testing the lenses. Rabbits have worn them for 20 minutes without ill effects, he said. “The display has not yet been turned on while the rabbits are wearing the lenses,” he said. “But we have turned on the lenses while holding them with tweezers, and they work well.”

The light-emitting diodes and other semiconductor components of the display are made separately, then moved to the lens, which is made of the same plastic used in beverage bottles. Then the entire device gets a biocompatible coating.

“We embed everything in polymers similar to those in standard contact lenses,” he said. “The electronics and photonics are inside the plastic, so users won’t come in contact with them.”

So far, the group has been able to light up and control a single pixel. But the team hopes to increase the number of pixels gradually, to make higher resolutions, he said. “We will increase the resolution, and add color eventually,” he said.

A group led by Desney S. Tan, a researcher at Microsoft Research in Redmond, Wash., is working with Dr. Parviz.

“Our role is to come up with some of the applications for the technology,” Dr. Tan said, applications that are part of a research field he called augmented reality: the combining of digital and physical worlds, in which virtual information is layered onto a person’s view of the real world.

In one possible application, the eyewear could serve as the wearer’s personal whisperer at conferences and cocktail parties. “What if every time I passed by a person, I had their name come up on the display?” Dr. Tan asked. “We could even add information on the last time I saw them and what we chatted about.”

Via The New York Times