Fluid Focus Lens | Electronics Seminar Topic
Fluid Focus Lens
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 Fluid Focus 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 Fluid Focus 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.
