Researchers at the University of Central Florida (UCF) have developed zoom lenses which closely replicate the working of the human eye. These adaptive lenses should be manufactured at a dramatically smaller size than conventional zoom lenses without compromising clarity. After being granted no less than 5 U.S. patents, the UCF team has licensed the technologies to a manufacturing company. So we might soon get better zoom lenses in our cell phones and digital cameras.
The photo above shows such a tunable focus liquid lens in action. "The lens, developed by Shin-Tson Wu, provost-distinguished professor of optics, and his research team at UCF's College of Optics & Photonics, replicates the function of the human eye. The lens pictured was built for demonstration purposes, so the aperture was expanded to 15 millimeters, or roughly the diameter of a penny. The lenses that are made for miniaturized applications, such as for cell phones, are one to two millimeters in diameter (Credit: Shin-Tson Wu research group). Here is a link to a larger version" of this picture. And here are two links about Shin-Tson Wu research group's team members and a page devoted to Adaptive Focus Lens.
So how these tunable lenses are working? "Conventional zoom lenses rely on mechanically moving groups of glass or plastic lenses in order to adjust focus, magnification and field of view. Adaptive lenses, however, offer the ability to change focal lengths while eliminating the need to mechanically change the location of the lens. And it is all done in miniature. The typical aperture size for a lens in a cell phone, for example, is one to two millimeters in diameter. 'We have the ability to make these lenses from less than a millimeter to a couple of centimeters in size,' Wu said."
Wu has used two approaches to develop adaptive lenses. The first one involved liquid-crystal (LC) optics. But "the second approach, fluidic lenses, was inspired by principles of the human eye. The lens comprises a transparent optical fluid that is encapsulated within a flexible lens membrane and substrate. Upon compression of the lens body, the shape of the flexible lens membrane is modified, which results in an adjustment of the focal length of the lens. Since this approach provides a wide range of focal power with almost no optical loss, it can be implemented in compact camera modules, making it attractive for size-limited applications such as digital cameras and cell phones. Likewise, the LC lens offers the ability to control high-order aberrations that can lead to blurriness, making it attractive in applications such as free-space optical communications, adaptive optics, corrective eyewear and cameras."
As I've mentioned above, the researchers at UCF have been granted several U.S. patents for this technology. Here is a link to one of these patents provided by FreePatentsOnline.com. If you want to see the patent with all the figures, but you don't want to open a free account on this site, you can visit pat2pdf.org and enter the number of the patent, 6859333, to obtain a full PDF version of this patent about "Adaptive liquid crystal lenses" (9 pages, 434 KB).
Sources: University of Central Florida News, July 20, 2007, via EurekAlert!; and various websites
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