Of course, e-paper isn't all about e-readers. E Ink says it has shipped 30 million displays for use in everything from wristwatches to smartphones and smart cards. E-paper also holds promise for applications such as electronic signage and shelf labeling.
But the e-reader, with its high-volume sales, is driving the market. It is the only application of e-paper currently in mass production -- and E Ink controls 90% of that market segment, says Jennifer Colegrove, an analyst at DisplaySearch.
Overcoming e-paper's limitations
E-reader screens today suffer from two main drawbacks: screen-response times of about 200 ms (a page-turn time of about 1 second), make viewing video impractical; and the fact that today's e-paper-based e-readers offer only black-and-white displays. E Ink is working to solve both problems.
The performance of E Ink's e-paper displays has been doubling with each successive generation -- about every 18 months -- and "dynamic range reflectivity" (what we think of as contrast in an emissive display such as an LCD) has been doubling as well. "We see this trend continuing in the near term," says E Ink's Peruvemba. Page-turn times are poised to drop to about half a second -- better, but still not sufficiently fast to support full-motion video.
Last November, E Ink introduced its first color display, the Triton, and Hanvon Technology in China announced that it will begin selling the first color e-book reader to use the Triton technology in the Chinese market in the second quarter of 2011, and in the U.S. later in the year.
E Ink's Triton display has color filter overlays, which can have a negative effect on screen brightness, but the company says it compensates for that by using a brighter reflective background. The display supports a wide viewing angle, and the addition of color will be a big step up for e-paper-based e-readers.
Still, "the color reproduction [on the Triton display] is not even close to what you get on an LCD or OLED," says iSuppli's Jakhanwal. (Organic light-emitting diode is a competing low-power display technology that's steadily gaining traction in the smartphone market.)
One other Chinese company, Jinke Hanlin, showed a prototype Triton device at the 2011 Consumer Electronics Show, but there have been no additional product announcements yet.
Steve Secrist, an analyst at market research firm Insight Media, says the washed-out "comic book colors" of the Triton screen may have a hard time finding a market in the wake of the iPad. "It's kind of too little too late," he says. Instead, he sees a bifurcation of the market in which monochrome e-book readers hold one niche, while those who want a color experience opt for a color LCD tablet such as the iPad, which can offer brighter, more saturated colors.
And LCD technology may finally be ready to compete with another key advantage of e-paper displays. Pixel Qi has developed a transflective LCD technology that can be read in reflective mode in sunlight while supporting a transmissive backlight for indoor viewing. Beijing-based ZTE has introduced the ZTE Light 2, the first tablet PC to use the technology, in European and Asian markets, but it's not in the U.S. yet.
Pixel Qi's reflective mode doesn't compare to E Ink's e-paper technology for contrast and readability for black-and-white e-book reading, says Norbert Hildebrand, an analyst at Insight Media. "But when you want to read at night, there's no comparison."
E-paper isn't standing still, however. Going forward, e-paper displays will continue to incrementally improve screen response times while increasing screen resolution and contrast ratios. "We are improving the electro-optic features to get closer to printed paper," E Ink's Peruvemba says. The company's current generation of e-paper displays already beat low-quality newspapers and paperback novels for readability, he claims.
Generally speaking, that's true, says Insight Media's Hildebrand, because a cheap paperback often has yellowed or grayish paper that offers lower contrast. E Ink-based displays are "in that range," he says. "But for every paperback? I would debate that."