TECHNOLOGY FOR CHANGE

Eight New E-Paper Displays Vie for Your Eyeballs

R. Colin Johnson | Date: 02-26-10 | Comments

Today, every popular ebook uses the same Vizplex display from E-Ink. Apple's forthcoming iPad will use a conventional LCD, but eight other display alternatives will offer longer battery lifetimes and novel features that could win you over.

Amazon's Kindle, Barnes & Noble's Nook, Sony's Reader, Hearst Newspaper's Skiff, Spring Design's Alex, iRex's Digital Reader and Hanvon's WISEreaders all use the same electrophoretic display technology branded Vizplex by its inventor, E-Ink (a wholly owned subsidiary of Primeview International, Hsinchu, Taiwan).

Electrophoretic displays use tiny microcapsules containing the same black and white pigments as ink and paper, creating a display uncannily similar to real paper.

The reason for E-Ink's virtual monopoly on e-reader displays is that its electrophoretic technology has no backlight, so your battery does not run down while you are reading a page like on Apple's iPad. Plus, electrophoretic displays use the same black and white pigments as real ink and paper, just contained inside tiny microcapsules, making its pages appear uncannily similar to real ink on paper.

Two vendors are working to offer their own versions of electrophoretic displays, but which add color and video capabilities. SiPix (owned by AU Optronics, Hsinchu, Taiwan) puts different colored electrophoretic pigments into microcups, and Bridgestone Tire (Tokyo) uses dry colored pigments to provide video frame rates.

The most conventional alternatives to all these electrophoretic displays are cholesteric nematic LCDs being developed by Fujitsu, Fuji Xerox, Hitachi, Kent Display, Kodak, Nemoptic, Varitronix and ZBD Display. Cholesteric nematic LCDs use a passive, instead of active, matrix to achieve low power, but retain the full color capability of a conventional LCD.

One of the most novel alternatives to electrophoretic displays is Quallcomm's Mirasol, which fabricates tiny interferometers at each pixel location to color light using micro-electro-mechanical systems (MEMS).

A similar approach is being developed by Opalux for its photonic crystal display. Opalux electrically alters the nanostructures of a photonic crystal to reinforce selected colors of reflected light.

Another novel alternative is called electrowetting by Liquidvista. Originally developed by Philips, electrowetting uses drops of colored oil that spread out to color a pixel. When a voltage is applied, the colored oil shrinks into the corner of pixel, making it transparent.

Similar to electrowetting is the electrofluidic display being developed by Gamma Dynamics. Like electrowetting, fluid droplets spread out to color pixels, but added microfluidic channels "suck up" droplets when they are not being used.

A rival display technology that can be cast onto plastic or paper substrates is called "electrochromic." Being developed at Acreo, Aveso, Ntera and Siemens, electrochromic displays use dyes that electrically change color.