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.
