The new display is comprised of a thin-film transistor (TFT) array, which can impart both positive and negative charges to different areas of its surface, and an electricity-conducting layer of clear fluid. Within this layer are millions of tiny capsules of black and white pigments that respond to charge. Thus, a negative voltage on the TFT causes white particles to move to the surface while a positive one moves black particles to the top to create the appearance of print. Yu Chen and his colleagues at E Ink Corporation report that the display can be bent 20 times and rolled into a cylinder with a diameter of 4 millimeters without compromising its performance (see image).
Changing the ink arrangement on the novel screen takes 250 milliseconds, which is sufficient for electronic paper applications but is too slow for video displays. Chen notes that most of the major technical challenges have been solved; however, it will still be several years before digital papers appear at a newsstand near you.