Wide-angle, high-resolution lenses are usually bulky and expensive — as a rule, the more resolution you want from a lens, the bigger it has to be. This has been a fundamental rule of optics for centuries.
That may finally change. Scientists at the University of California, San Diego, have developed a high-resolution, wide-angle lens that also zooms like a telephoto lens in one tiny package that’s one-tenth the size expected. This would be a big plus for cameras built into smartphones, putting them on a par with DSLRs, and for imaging systems on unmanned aircraft and even satellites, where weight and size are at a premium.
The researchers built the lens from layers of curved pieces of glass stacked on top of each other, with the curves having a common center — imagine an onion cut in half. The configuration allowed for wide-angle images that did have the distortion seen in fisheye lenses.
Next, the UCSD attached optical fibers to the back of the lens designed to gather the maximum amount of light coming through the glass. The end of each fiber was polished to a curve that aligned exactly with the lens’ surface. As light passed the through the lenses, the optical fibers picked it up and delivered it to the computer where it was converted into a digital signal.
The engineers tested the lens at distances from a half a meter to 500 meters. Resolution was the equivalent of 20/20 human vision. That’s competitive with some of the best professional lenses currently used, and it fits in a package only a couple of inches across.
The team, led by engineering professor Joseph Ford, will present the new lens technology at the Optical Society of America’s annual meeting, Oct. 6 to 10 in Orlando, Fla. Ford will outline a prototype system with a 12 millimeter focal length, making it ultra-wide-angle, and an fiber optic bundle linked to a 5-megapixel image sensor. His team is working on a 30-megapixel prototype, and a press release says he plans to shoot for an 85-megapixel imager with a 120-degree field of view. “All in a volume roughly the size of a walnut.”
Credit: Courtesy UCSD