31-01-2009, 12:55 AM
The camera phone is one of the hottest-selling items in all of consumer electronics. The little gadgets have become so ubiquitous that hardly anyone finds it odd anymore to see tourists squinting with one eye while pointing their cell phones at a Buddhist temple, a Greek statue, or a New York City skyscraper. It's easy to see why analysts expect that camera phones will outsell conventional digital cameras and traditional film cameras combined.
But as anyone who has ever seen them can attest, the images that come out of camera phones leave plenty to be desired. Part of the problem is their CMOS imaging chips, which typically have a sensor array of only about one mega pixel?a half or less of the number in a low-end digital camera. When they are, however, the only thing we may see more clearly is the other weakness of these cameras: their tiny, fixed-focus lenses, which have poor light-gathering and resolving power.
Here is a solution. It's modeled on the human eye, with its remarkable optical capabilities. It is called the FluidFocus lens. Like the lens of the eye, this lens, which we built at Philips Research Laboratories, in Eindhoven, the Netherlands, varies its focus by changing shape rather than by changing the relative positions of multiple lenses, as high-quality camera lenses do. The tests of a prototype FluidFocus lens showed that it can be made nearly as small as a fixed-focus lens. Fixed-focus lenses use a small aperture and short focal length to keep most things in focus, but at the sacrifice of light-gathering power and therefore of picture quality.
At the same time, the prototype lens delivered sharpness that is easily on a par with that of variable-focus lenses. In fact, the optical quality of a liquid lens combined with a good imaging chip could soon give cell phone snapshots quality that rivals images from conventional- and much bulkier- digital cameras.
