E-paper takes off

To manufacture its electrophoretic-display (EPD) e-paper, pioneer E Ink produces a "sheet" that comprises microencapsulated particles in a transparent liquid; a common electrode; and a release layer, which display makers or OEMs remove to laminate the sheet to a backplane. Inside the capsules are positively charged white and negatively charged black particles.

E Ink's "sheet" technology has already been adopted in more than 10 million Motorola cell phones. The same technology is also used in Kindle, the portable book reader Amazon.com launched last year in the U.S. market, as well as seven other e-book readers now in production.

E Ink also exhibited an e-paper device that accommodates a stylus pen input. It is built around a control IC—the S1D13521B, jointly developed by Seiko Epson and E Ink—along with E Ink's AM300 development kit and a built-in electromagnetic induction-type tablet made by Wacom.

Wacom specifically developed a very thin, light panel: At 0.35 mm and 40 grams, it's half as thick as and half the weight of its predecessor. To trim the weight, Wacom engineers used PET film in place of a glass substrate.

"We expect five to six companies to launch products based on the AM300 development kit this summer," said Ryosuke Kuwata, vice president of E Ink.

Fujitsu, meanwhile, showed off e-paper technology with a multicolor cholesteric LCD. The panel, which does not use color filters, is constructed by combining three stacked display layers—one each for red, green and blue. The company exhibited an 8-inch, full-color PDA display panel capable of showing 1,024 x 768 pixels.

For its part, Bridgestone is working on a proprietary EPD technology called Quick Response Liquid Powder Display. QR-LPD is based on "electro-liquid powder," which straddles liquids and conventional powdered solids. The electro-liquid powder, which flows like a particulate suspension, is extremely sensitive to electricity, thus ensuring fast responsiveness: Response time is as fast as 0.2 ms. The powder comprises positively charged black particles and negatively charged white ones.

Bridgestone exhibited an A3-size full-color panel (4,096 colors) using a color filter. The company said it has also developed a foldable display. n

Yoichiro Hata is managing editor of EE Times Japan, where this article first appeared. Additional reporting by David Lieberman, a freelance technology journalist based in Chapel Hill, N.C.