The announced design includes a 7.5" full-color, transmissive screen costing $35. The project however is developing a larger, dual mode, lower power display at a projected cost point of $12. The display in development uses E Ink.
“Electronic Ink” (E Ink) is a display technology that grants device users larger displays with paper-like readability, ultra-low power consumption and thin, light form factors . Its history is in the delivery of eBooks – but now the planners for the $100 laptop are hopeful that the technology will evolve sufficiently to be adequate as a display for the laptop.
E Ink displays offer greatly reduced power consumption as compared to transmissive LCDs as well as newer emissive technologies (OLED, FED, PDP). Lower power consumption translates to longer battery life, and perhaps more importantly, the ability to use smaller batteries in electronic ink devices – reducing device weight and cost. (Once an image is written on an electronic ink display, it will be retained without additional power input until the next image is written. Hence the power consumption of an electronic ink display will ultimately depend upon the frequency at which the displayed image is changed and not how long a display is read.)
Electronic ink is a proprietary material that is processed into a film for integration into electronic displays . Although revolutionary in concept, electronic ink is a straightforward fusion of chemistry, physics and electronics to create this new material. The principal components of electronic ink are millions of tiny microcapsules, about the diameter of a human hair. In one incarnation, each microcapsule contains positively charged white particles and negatively charged black particles suspended in a clear fluid. When a negative electric field is applied, the white particles move to the top of the microcapsule where they become visible to the user. This makes the surface appear white at that spot. At the same time, an opposite electric field pulls the black particles to the bottom of the microcapsules where they are hidden. By reversing this process, the black particles appear at the top of the capsule, which now makes the surface appear dark at that spot.
To help explain how the technology works, compare the millions of microcapsules inside the ink to clear beach balls. Each of these beach balls is filled with hundreds of tiny, white ping-pong balls. And instead of air, the beach ball is filled with a blue dye. If you looked at the top of this beach ball, you would see the ping-pong balls floating in the liquid, and the beach ball would appear white. But if you looked at the bottom of the ball, it would appear blue. Now, if you were to take thousands of these beach balls and lay them out on a field, and make the ping-pong balls move between the top and bottom of the beach balls, you could make the field change color.
The display technology is a critical part of the plan for the $100 laptop. Flat-panel laptop displays cost hundreds of dollars – the $100 laptop plan requires a display costing no more than $35. Early versions of E Ink screens could only handle text, but companies are working on versions for full-motion video.
E Ink's latest breakthrough is the first full-color electronic paper display suitable for mass production. Their press release describes the technology:
"This electronic paper color prototype achieves 12-bit color in a 400x300 pixel format with resolution of 83 pixels per inch, using a custom color filter from strategic partner Toppan. The color filter design has a high-brightness layout (RGBW) that preserves the paper-like whiteness of the background page while enabling deep blacks for text and a range of colors and tones for images. A smart algorithm uses color sub-pixels to smooth black and white text, for enhanced legibility equivalent to a printer. The display diagonal is 6 inches, similar to a paperback book in size. 'The gates are finally open for product designers to use color electronic paper in mobile devices.'"
"E Ink's electronic ink technology creates an image that looks like a printed page from all angles and maintains the same contrast ratio under all lighting conditions, including direct sunlight. Aimed at handheld devices, the display uses up to 100 times less energy than a standard liquid crystal display (LCD), so product designers can shed weight and greatly extend battery life. 'Our display can be updated in a fraction of a second, enabling menus, scroll bars and animation. The screen can easily switch between black and white text or color windows and icons.'"