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Next digital screen could fold like paper

Scientists tinker with displays for books, clothing, and military gadgets that are as thin as newsprint and as durable as fabric.

By Lori ValigraCorrespondent of The Christian Science Monitor / January 8, 2004

Clothing for travelers or soldiers that alters color to fit the environment. Books that change content on request. Computer displays so thin they can be manufactured on a roll and cut to size like kitchen foil. Even paper that emits sounds or can be erased and reused thousands of times.

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These aren't the smart gadgets of fictional spy movies: They are applications of emerging electronic-display technologies. And some will hit the market as early as this year. Technologists hope the new displays will usher in an era in which users drop clunky screens for flexible, portable ones so thin they can be rolled up like a newspaper. The benefits of the new gadgets are obvious: One such display could replace stacks of books that weigh down a vacationer's suitcase or a student's backpack and provide content that can be updated instantly.

Even a soldier's uniform could function as a flexible display by automatically changing color to camouflage him as he walks from the jungle onto a dirt road. Likewise, a businesswoman's suit could switch from navy blue to white as she travels from a cold to a warm climate, reducing the outfits she must pack.

While many of these scenarios are at least 10 years away, precursor products such as "smart" papers and ultra-thin glass displays are poised to show up in 2004. In Japan, Sony Corp. and Matsushita Electric Corp. plan to start selling electronic books (e-books) the size of DVD cases early this year.

Since their debut in the mid-90s, e-books have earned notoriety for being hefty, expensive, and not interchangeable among publishers. The new versions promise to be lighter, easier to use, and eventually less expensive.

"In Japan, a large percentage of the population spends hours each day commuting on trains. Europeans also purchase large volumes of reading material," says Michael McCreary of E Ink Corp., a Cambridge, Mass., electronic-ink (e-ink) company that uses technology developed at MIT's Media Lab. "Japan is a good market to start in, but this will go worldwide."

Initially, both the Sony and Matsushita e-books, which use active matrix technology, will be monochrome, but color versions are expected in a few years. Sony's e-book comes from a joint effort by E Ink, Toppan Printing Co., and Royal Philips Electronics.

The e-ink, which closely resembles printed text, comprises tiny capsules filled with positively charged white pigment chips and negatively charged black ones. They respond to electric charges to create text and images, says Mark Johnson, a scientist at Philips. Content is downloaded via wireless networks.

Toppan coats the e-ink onto a thin plastic film. Philips places that film onto a sheet of glass laden with electrodes. It also adds electronics around the perimeter to control the ink.

Matsushita's e-book, called Sigma Book, will be sold under the Panasonic brand. It uses cholesteric liquid-crystal display (LCD) technology, with dark blue pigment on a light background. Cholesteric LCDs create images by switching between a color and black when a small electric field is applied. The images may not be as crisp as active-matrix ones, but the displays cost less, says Prof. John West, director of Kent State's Liquid Crystal Institute, where the technology was developed.

Both the Matsushita and Sony e-books will have dual screens that open like a paper book and both will be readable under sunlight, says Dr. West.

They eventually could be made of a pliable, polymer backing that resembles paper. Bill Doane, head of Kent Displays, says his company may have flexible plastic cholesteric displays ready by 2006. "You can make large volumes of them at very low cost," he says.

E Ink is moving in the same direction with its "Radio Paper." Dr. McCreary says the goal is to have a display that looks and feels like newspaper, but can be updated wirelessly. He says it could be ready by 2007 or 2008.