E-paper (sometimes called radio paper or just electronic paper) is a portable, reusable storage and display medium that looks like paper but can be repeatedly written on (refreshed) - by electronic means - thousands or millions of times. E-paper will be used for applications such as e-books, electronic newspapers, portable signs, and foldable, rollable displays. Information to be displayed is downloaded through a connection to a computer or a cell phone, or created with mechanical tools such as an electronic "pencil". There are a number of different technologies being developed: Xerox, in partnership with 3M, has created an e-paper called Gyricon that is expected to be marketed in the not-distant future and Lucent, in partnership with a company called E Ink, is working on a device (also called E Ink) that is expected to be available within the next few years. Both of these technologies enable a black (or other color) and white display; Philips is working on a type of e-paper that will be full-color, but say that the product is at least 10-15 years away.
The Gyricon version consists of a single sheet of transparent plastic, containing millions of tiny bichromal (two color) beads in oil-filled pockets. Text and images are displayed through a rotation of the beads that occurs in response to an electrical impulse: a full rotation displays as black or white, and a partial rotation displays as gray shades. Like traditional paper, Gyricon has - and needs - no lighting component.
Lucent's E Ink device uses electronic ink and combines thin, plastic, flexible transistors with polymer LEDs (light-emitting diodes) to create what are called smart pixels. The process involved - which is not dissimilar to traditional printing processes - uses silicon rubber stamps to actually print tiny (as small as those for the Pentium III processor) computer circuits onto the surface. E Ink uses electronic ink for display: a liquid plastic substance consisting of millions of tiny capsules filled with light and dark dyes that change color - charged dye particles move either up or down within the capsules - when exposed to an electric charge. According to Paul Drzaic, the director of display technologies, prototypes of the device have been running on watch batteries. The E Ink technology has been used for retail signs.
Neither the Lucent/E Ink version nor the Gyricon version require a constant power source; the initial charge creates the display, which then remains fixed until another charge is applied to change it. Low power demand is an important consideration for a technology that is intended to - at least partially - supplant a power-independent, standalone application like paper. The challenge involved in creating viable e-paper is to develop a material that has the desirable characteristics of traditional paper in addition to its own intrinsic benefits (such as being automatically refreshable). Like traditional paper, e-paper must be lightweight, flexible, glare-free, and affordable, if it is to gain consumer approval. Developers of both the competing e-papers claim to have accomplished most of these qualities in their products. The first e-paper products will be Gyricon-based: portable, reusable pricing signs for stores that can be changed instantly through a computer link; the first Gyricon-based electronic newspaper is expected to be available within the next 3 years.