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The Next Camera Lens Technology???

Tiny Camera Lens Focuses Using Just Oil and Water

ABCNEWS
By Paul M. Eng


March 23 - Oil and water may not mix. But researchers say the two incompatible liquids can unite to create a unique artificial lens that mimics the workings of the human eye.

Such a lens was introduced recently by Royal Philips Electronics of the Netherlands. Like many common camera lenses, the so-called FluidFocus lens is "variable-focus" — able to bring either near or distant objects into razor-sharp clarity through simple manipulation.

But unlike traditional lenses, the Philips prototype doesn't require moving mechanical parts or a lot of power. That could makes it an ideal optical solution for next-generation digital cameras or other optical devices.

The mechanics of the lens is based on an interesting phenomenon that occurs with water, explain scientists Stein Kuiper and Benno Hendricks at Philips.

"If you put water on a greasy surface, it will take a spherical shape. And if you put it on clean surface, it spreads out," says Kuiper, the senior research scientist on the Philips FluidFocus project.

In other words, the surface of the liquids formed concave or convex curves similar to shape of lenses used in cameras and eyeglasses. And both Kuiper and Hendricks figured out an innovative way to control the shape — and thus the focal power —of their liquid lens.


I See Cylinders

The FluidFocus lens consists of a tiny sealed glass tube filled with two non-mixing fluids — a non-electrically conducting oil and an electrically conducting solution of water and soap. The interior walls and one end of the tube are coated with clear Teflon-like coating that actually repels water, causing the soapy water solution to form into a hemisphere shape at one end of the tube.

When an electrical charge is applied to the walls of the tube, the water becomes attracted to the sides of the cylinder and the oil flattens the center of solution's hemisphere. Increase the voltage even more, and the water "climbs" up the sides of the tube's walls, forming a convex shape.

Hendricks says the walls of the tube has to be charged with only tiny amounts of power to bend the lens from near-focus to far-focus capabilities. And the lens will retain its shape until the amount of charge is changed.


Experimental versions of a lens about three millimeters in diameter have been able to focus on objects as close as five centimeters and all the way out to "infinity." And according to the scientists, they've been able to rapidly change the so-called focal length of the liquid lens over a million times with no measured loss of optical performance.


Faster Than a Blinking Eye

The mechanics of the FluidFocus lens is similar to how a human eye works as it shifts focus from near object to distant items. But Hendricks says their artificial eye is much faster than its flesh-and-blood counterpart.

"A human eye has a typical response time of about 200 milliseconds," says Hendricks. With the proper auto-focusing algorithms, Hendricks and Kuiper have been able to change their prototype lens in as fast as 10 milliseconds, or 20 times faster.


The quick response time, low-power requirements, and simple construction of the artificial lens will make it an ideal candidate for use in devices that need a rugged, yet flexible optical lens — such as robots or endoscopes used in the medical field.

But eventually, the tiny lenses could make its way into digital cameras or other consumer devices, say Hendricks and Kupier.

"At the moment, there are practically no miniature cameras that can focus variably. They are all fixed-focus [cameras]," says Kupier. "A lot of people are trying to solve this with a mechanical system. But we think we have one of the possible systems to replace those fixed-focus systems."



Focusing on the Near Future

Still, both scientists admit there are still minor obstacles to work out.

For example, they still must test how well a liquid lens would survive the rough-and-tumble shocks cameras and other optical systems face in the real world. Would a FluidFocus lens on a planetary robot explorer, say, operate at extreme temperatures?

And there is the matter of size. For now, FluidFocus works best at small scales — lenses less than a centimeter in diameter. Larger lenses require more power, take longer to focus, and are more susceptible to "shock." (Picture how much easier it is to upset an oil-and-vinegar salad dressing in bottle than a thimble.)


Those drawbacks may leave the picture for the liquid lens a tad cloudy. But both Hendricks and Kupier are confident these aren't major drawbacks. And they say as they figure out how to mass produce these lenses — perhaps by drilling and filling large sheets of glass with their concoctions — FluidFocus could become a viable commercial product for Philips within a year or two.

http://abcnews.go.com/Technology/FutureTech/story?id=99560&page=1