Will E-Paper Still Need E-Ink?

E-Ink Corporation designs and builds electrophoretic displays (EPDs), a type of electronic paper (e-paper) used by e-readers. Founded in 1997, the Cambridge, Massachusetts company is the master of a proprietary material called electronic ink. Made of millions of microcapsules, electronic ink suspends positively-charged white particles and negatively-charged black particles in a dielectric fluid. Applying a negative electric field causes white particles to rise to the top of the display and black particles to fall. Applying a positive electric field moves black particles to the top of the affected area.

The electrophoretic technology that E-Ink pioneered made the company a display market leader, but will its dominance last? Although e-readers are hardly ubiquitous, some consumers are demanding color displays instead of black and white ones. E-Ink's initial response has been to place a color filter over its black and white displays. These e-readers are scheduled to ship in China, but critics complain that the display colors are muted and that full-motion video falls flat on its face. E-Ink's sales and marketing department is minimizing these complaints, but E-Ink developers are working on a totally different chemistry.

Meanwhile, competitors such as Bridgestone are designing bi-stable, electrophoretic displays that nestle charged powder particles between ribs instead of suspending them in dielectric fluid. Mounted on plastic substrates, these displays use a relatively inexpensive roll-to-roll manufacturing process. Most importantly, Bridgestone's new chemistry produces displays with response times suitable for video-speed applications.

Source: SPIE