Where are the E-book Readers With Colour Display?
Electronic book readers may be the future of publishing, but in one important respect, they’re still stuck in 1950: Almost every e-book reader on the market has a black-and-white display. Most can’t display more than a handful of different shades of gray.
The hitch is that color e-ink technologies aren’t anywhere near ready for prime time. Amazon chief Jeff Bezos recently told shareholders that a Kindle with a color screen is “multiple years” away.
So what’s the technological holdup? To understand that, you first have to understand how E Ink’s black-and-white displays work. Electronic ink, pioneered by the company, is composed of millions of microcapsules. Each microcapsule has positively charged white particles and negatively charged black particles suspended in a clear fluid. When a positive electric field is applied, the black particles are attracted to the top and become visible to the user. That makes that area appear black. The reverse is also true: A negative electric field draws white particles to the top, making the area appear lighter. For an electronic display, the ink is printed on a sheet of plastic film, and a layer of circuitry is laminated to it to drive the ink.
For a color display, E Ink needs to put a color filter on top of its black-and-white display. A color filter usually has four sub-pixels — red, green, blue and white — that are combined to create each full-color pixel. That also means reduced brightness of display.The color filters also block a large amount of light, making the displays look dull and washed out, says Young. “The challenge is to balance the color output of the filter with the amount of light blocked by it,” he says. The good news? When E Ink figures it out, its black-and-white displays will be better than ever, says Young.
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