E-Ink-Info is reporting that Philips Research has developed a new color epaper technology that is brighter and clearer than LCD. Kars-Michiel Lenssen headed the work at Philips Research. This new color epaper technology is three times brighter than displays that require the use of a color filter; LCD technology for the most part requires a color filter, an optical layer that absorbs a considerable amount of brightness. According to Lenssen, “This is the closest an electronic-paper technology ever gotto printed paper.”
The common epaper technology, which is currently dominated by E Ink, employed in Amazon’s Kindle to Sony’s PRS-700 makes use of electrophoresis where colored particles (usually black) are dispersed in a liquid. These particles are controlled using an electric field. Each pixel has a microcapsule filled with black oily liquid as well as very small white particles that are suspended. These particles are charged and when an electric field is applied the particles migrate to the top of the microcapsule and changing the way light reflects off of the pixel, in effect making it lighter or darker.
Philips Research turned the traditional epaper pixel on its side in order to tune it to different shades of color. The approach is called in-plane electrophoretics that involves suspending colored particles in a clear liquid and moving them horizontally instead of vertically. Each epaper pixel is composed of two microcapsule chambers with one containing yellow and cyan particles and the other containing magenta and black particles. Within each microcapsule one set of colored particles is charged positively while the other is charged negatively.
Voltage is carefully controlled and applied to the electrodes that are located at the edges of the pixels. The colored particles can be spread across the entire pixel or removed from view by hiding them under the electrodes. Shades of color is generated by controlling how many of each group of colored particles are visible. To generate a white pixel all of the particles are shifted underneath the electrodes and the white substrate underneath is revealed. Philips’ in-plane electrophoretics make use of cheaper and simpler electronics to address the pixels that lead to easier manufacturing especially flexible displays.