SAN FRANCISCO, Sept. 25 (UPI) -- Dutch researchers have taken the concept of replacing traditional ink and paper with thin, flexible, reusable electronic displays a step further. They have developed a technique that may permit movie fans to watch videos on their cell phones, personal digital assistants or even articles of clothing.
Unlike other emerging technologies of its genre, the novel system can switch rapidly from one color to the next, setting the stage for the development of a new generation of "electronic paper" that one day might serve as a screen for moving images, the scientists speculated.
In contrast to the traditional, wasteful wood-pulp staple of publishing that requires an additional supply for every reprinting, the reusable Digital Age version employs electronics embedded in a flexible, paper-thin piece of glass or plastic connected to a mobile phone or other wireless power source that provides a constant, uninterrupted flow of information on the same display.
"We're still at the very early stages of development," said Robert Hayes, principal scientist in the Inorganic Materials Department at Philips Research Laboratories in Eindhoven, The Netherlands, an arm of the giant Royal Philips Electronics that posted some $40 billion in sales last year. "But we've had a fantastically positive reaction to the small demo screens we've created."
Their version is a cut above other prototypes in two key features: the speed required to display video or animation and the brightness necessary to present color images, the inventors declared. It is the fastest and clearest of the e-paper set -- on and off the laboratory shelf -- they attest.
Hayes and B.J. Feenstra overcame both problems with a solution based on the age-old premise that oil and water do not mix. Taking advantage of this natural repulsion, they devised a design of tiny chambers, or pixels -- using the now-standard term of computer screen graphics -- with a water-repelling base that sits atop a bright white material.
The display works through a phenomenon called electro-wetting, in which an electrical current alters the nature of a normally hydrophobic surface, making it attract, rather than resist, water.
The team placed a drop of black or colored oil in the bottom of each chamber and topped it with water. The oil spread across the base, obscuring the white background and creating a black or colored pixel.
Applying voltage swept the oil to the side, like a parting curtain, exposing the white foil underneath and completely changing the pixel's appearance. Full-color displays can be achieved by combining units of yellow, cyan and magenta -- the same color trio used in conventional television -- scientists explained.
"We have shown that electro-wetting (essentially voltage-induced fluidic motion) can be used to make an optical switch that can meet the requirements of electronic paper," Hayes told United Press International.
The pictures are four times brighter than reflective liquid-crystal displays -- such as those seen on mobile phones, PDAs, digital watches, portable computers and calculators -- and twice as bright as rival technologies, the researchers said.
"Unlike other types of display, if you're in a well-lit space or outside, you can still see the display easily, from any angle and with the same high contrast, and it doesn't need backlighting," Hayes said. "It opens the way to a completely new type of display that can be used under a wide variety of lighting conditions, especially in very bright outdoor conditions."
The tiny dots can change colors fast enough to generate 100 images a second -- more than three times as fast as American, TV-quality video.
"It is probably the fastest (e-paper display) demonstrated to date," Yu Chen, principal engineer at Kovio Inc., a nanotechnology company in Sunnyvale, Calif., told UPI.
Chen captured wide media attention in May when he reported in the British journal Nature the development of an electronic-ink display screen just three times the width of a human hair, flexible enough to be rolled into a tube a mere 4 millimeters across, and viewable from almost any angle.
The display was too slow for video, however, conceded Chen, who at the time of the announcement was working at E Ink Corp. of Cambridge, Mass., a leading developer and marketer of electronic-ink technology for paper-like displays. The company expects to begin marketing its first e-paper product in 2004, in the form of electronic readers.
"(Ours) certainly is the only (display) to combine video-speed with a brightness that goes beyond normal RGB (red-green-blue) segmentation," Hayes said of the moving-picture advance.
As a bonus, the system, which uses a 15-volt battery, operates at low power levels, making it usable in a wide range of electro-optic devices, scientists said.
Robert Sprague, vice president and chief technology officer of Gyricon Media Inc., of Palo Alto, Calif., deemed it "an interesting piece of research."
Gyricon, a Xerox spinoff dedicated solely to e-paper development, recently completed a preliminary trial run of one of its own products -- glare-free, re-imageable, wireless retail signage hooked up to the department store cash register to permit consistent advertising of the most current pricing -- and is planning a commercial rollout next year.
Hayes and company will need to wait longer before making a public debut.
"The devil's in the details," said Paul Drzaic, vice president of Advanced Development Programs at Alien Technology Corp., of Morgan Hill, Calif., maker of radio-frequency identification tags, and former technology director at E Ink.
"They've got a lot of work ahead of them before they make a real display," he said in a telephone interview.
Hayes, who has devoted the past three years to the project, expects the first, single-color products to hit the market in three to four years. They will be of greatest interest to consumers using mobile phones and PDAs and needing full color and video content, he predicted.
One future possibility might be clothing or wearable devices that can show movies, the study authors wrote in Nature.
"I think the significance of this study is that it confirms the growing research and excitement around electronic paper as an alternative to normal computer displays," said Russ Wilcox, E Ink vice president and general manager.
Gyricon's entry into the commercial market marks an important beginning, said industry analyst Amy Wohl, president of Wohl Associates of Narberth, Pa. "Gyricon is running a pilot with a Macy's in New Jersey, and others are expected to follow," she told UPI.
Though it is too early to speculate about what products will capture the public imagination -- and pocketbook -- there is little doubt about the size of the prize, researchers said.
"There is no real question that there is huge market potential for easily manufacturable (i.e. cheap) e-paper technologies," Hayes said. "The as-yet-unanswered question is which technology will become dominant."
It is generally agreed, however, he told UPI, "that the winning reflective display technology will access a billion-dollar market."
