Multi-part lens expands and contracts to change focus. A lens invented at The Ohio State University combines the focusing ability of a human eye with the wide-angle view of an insect eye to capture images with depth.
The results could be smartphones that rival the photo quality of digital cameras, and surgical imaging that enables doctors to see inside the human body like never before.
Engineers described the patent-pending lens in the Technical Digest of the 25th IEEE International Conference on Micro Electro Mechanical Systems.
"Our eye can change focus. An insect eye is made of many small optical components that can't change focus but give a wide view. We can combine the two," explained Yi Zhao, associate professor of biomedical engineering and ophthalmology at Ohio State. "What we get is a wide-angle lens with depth of field."
That is to say, the lens shows a wide view, but still offers a sense of human-like depth perception: as close objects come into focus, far away objects look blurry.
Zhao's prototype lens is made of a flexible transparent polymer filled with a gelatinous fluid similar to fluid inside the human eye. It's actually a composite of several separate dome-shaped fluid pockets, with small domes sitting atop one larger dome. Each dome is adjustable, so that as fluid is pumped into and out of the lens, different parts of it expand and contract to change the overall shape-and thus, the direction and focus-of the lens.
This shape-changing strategy is somewhat similar to the way muscles in the human eye change the shape of the lens tissue in order to focus. It differs dramatically from the way typical cameras and microscopes focus, which involves moving separate glass lenses back and forth along the line of sight.
The shape-changing lens could potentially offer the same focusing capability as multiple moving lenses in a single stationary lens, which would make for smaller and lighter cameras and microscopes.
In particular, Zhao is interested in using the lens in confocal microscopes, which use a system of moving glass lenses and a laser to scan three-dimensional images of tiny objects.
"We believe that it is possible to make a confocal microscope with no moving parts," he said.