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.

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.

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.

Researchers at Xerox Corp.'s Palo Alto Research Center recently devised a technique to "print" plastic transistors similar to the type used to control today's flat-panel displays. The new process uses semiconductor ink and a modified ink-jet printer. The transistors can be used to produce electronic displays that roll up.

Digital screens on tents

The potential value of flexible displays isn't lost on the military. The US Army Research Lab plans to spend $43.6 million over five years on a flexible-display center at a US university to be identified early this year, says Bob Pinnel, chief technology officer at the US Display Consortium in San Jose, Calif. Other branches of the military also are interested.

"DARPA [the Defense Advanced Research Projects Agency] is looking at 'immersive imaging,' where the entire interior of a tent will have displays that can simulate conditions for battle preparation, or remote cockpit and field training," Dr. Pinnel says.

Future soldiers will access more information than now, says David Morton, a physicist and manager for the Army Research Lab in Adelphi, Md. Their uniform sleeve, for example, could be a display showing a map or a manual to repair equipment in the field. "Flexible displays will be pervasive in the Army," Dr. Morton says.

One hurdle being worked on is the heat generated during display manufacturing, he says. It can damage the plastic display components. Color displays are in the early stages of development, and could be used as cloth for a digital camouflage suit, but they must be able to withstand wear and tear and washing. An even bigger challenge is to devise a reliable manufacturing system.

"Our goal in 10 to 15 years is to go to a flexible substrate [display backing material] that can be printed roll-to-roll like newspapers, then cut to size," Morton says.

Electronic fashions

In the private sector, "there already is a great interest in having flexible displays in fashions, including jewelry that can change colors as it is worn," says Kent State's West. Also, wallpaper in homes could become a giant flexible display that changes color or images.

Nearer term, e-book companies will face more traditional challenges, such as working out intellectual property, royalties, and other content issues with publishers.

An even more basic question remains: Can consumers wean themselves away from paper and embrace the gee-whiz display technologies?

As display technologies march forward, so, too, do those for "smart" paper. One type can be electronically erased and rewritten thousands of times by feeding it through a special companion paper. Japan's Ricoh Co., Ltd. has developed several types of "smart" paper that will be sold this year. Two other Japanese companies, Shinsho Corp. and Majima Laboratory Inc., have developed experimental rewritable paper they say is the first to use color. It also needs its own printer.

T-Ink Inc. of New York is taking a different approach with an electrically conductive ink that can make sounds or light up. It already is being used by McDonald's Australia in Happy Meals. The Happy Meal toy lights up as it interacts with ink printed on the meal box or tray liner. Likewise, children using Super Color educational products hear feedback if they write a correct answer to math or spelling questions. The marker they write with activates the conductive ink on the paper.

"The ink is printed on regular, disposable paper," says Andrew Ferber of T-Ink. He says the ink can be printed onto almost anything, including garments, wallpaper, automobiles, and devices like cellphones - and it will be washable. "There's no industry we can't go into."

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