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Scientists Johan Feenstra and Rob Hayes think they’ve figured out how a process called electrowetting can make paper that can do anything a videoscreen does. So far, though, all they’ve got to show for their efforts is a tiny piece of e-paper one centimeter square--only 225 pixels, or picture elements. That won’t be nearly enough for headlines and news videos. The only hint of the technology’s potential is a laptop presentation the inventors have set up. It features Professor Shape, Harry Potter’s teacher, holding an electronic newspaper with an embedded video clip. "That’s what we want," says Hayes.
They’re likely to get it. Late last month in Tokyo, Sony took an important leap in this direction by introducing Librie, an e-book reader. Although it’s available only in black and white, Librie has the most important characteristic of paper: it reflects natural light. That means it can be read on sunny days or viewed from any angle. You can even choose your own font size. Is this finally the beginning of the end of paper
The answer is closer to "yes" than you may think. The holdup so far has been user-unfriendly screens, but now e-paper no longer relies on back-lit displays. A reflective display is easy on the eyes, with twice the contrast of computer screens and up to six times the brightness. It uses power only when changing the page, so a battery can last 300 hours. Several firms are competing for leader ship. The Philip’s display on Librie uses technology from Massachusetts-based E-Ink Corp. An electric charge moves either black or white capsules to the surface of the page in patterns that form images. Gyricon Media uses rotating balls with one black side and one white side for signs and bill boards. Other companies are focusing on improvements in liquid-crystal displays.
The next challenge is to add color. One option for books would be a simple color filter, but that would block two thirds of the light. Guofu Zhou, who runs the E-Ink project for Philips, thinks products with colored ink can be ready for the market within seven years. He’s now focusing on e-paper that can display 16 or more gradations of gray, which would come in handy in medical imaging or to display black-and-white photographs at home.
Labs around the world are also racing to design a robust yet flexible backing. Philips researchers are working on a technology for laminating E-Ink on a plastic layer instead of glass, which would then roll into a pen-sized tube. A flexible product for mobile phones and digital cameras can be ready in three to five years.

What scientists Johan Feenstra and Rob Hayes did was that（）

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