A breakthrough development in e paper technology now allows e-paper to show true colors for the first time ever. Forget the RGBW mask!
Electronic paper goes by many names: e-paper, sometimes spelled ePaper, electronic ink and (generically, after the company that manufactures it) also e ink. All these names describe the same thing: a technology mimicking the appearance and readability of ordinary paper.
As we already wrote, electronic paper's amazing visibility is possible because the technology works on the basis of small ink particles moving under an electric charge. The particles are contained within microcapsules of the display film, suspended in a fluid. Changes in polarity move the black and white particles around the capsule, moving them closer to the display surface and outlining an image on screen.
What is simple in black and white becomes complicated when introducing additional hues. As a segway to full-color, tri-color electronic paper screens were developed such as the Spectra display, which introduced a third color ﹘ red or yellow ﹘ to the epaper film, this time contained in a micro cup instead of a capsule. This allowed for changes in current to raise the red or yellow ink to the screen surface and color the corresponding screen area.
Introduced for the first time at this year's SID Display Week, the new milestone in color EPD technology comes in the form of Advanced Color ePaper. For the first time ever, the electrophoretic display prototype can produce full color without the use of a color filter array, setting a new standard for bright, reflective e paper color displays. The magic behind the full-color electronic paper display runs close to the technology of the tri-color screen. The only difference is that the micro cup now contains four different pigments instead of three: yellow, cyan, magenta and white.
These pigment ink particles are not identical. In addition to their color, they also differ in size, polarity and the strength of the charge they carry. This means that changes in voltage result in different pigment particles moving to the display surface. The color combinations of these moving particles result in up to 32,000 display colors.
The new true-color display retains the ultra-low power functionality of electronic paper as well as its readability, but adds so much more to the game: the option of using the screens in all aspects of commercial signage. Think vivid billboards and menu boards similar to printed posters, but fully digitalized, full-color bus stops and traffic signs powered by solar cells, and much much more. The first commercially-available color e ink displays are expected to hit the market in approximately two years.