Electronic ink is a liquid substance, in development at MIT's Media Lab in partnership with a company called E Ink, that responds to electrical impulses to enable changeable text and image displays on a flexible surface. Electronic ink will be used for applications such as e-books, electronic newspapers, portable signs, and foldable, rollable displays. Electronic ink consists of millions of tiny capsules filled with dark dyes and containing negatively charged white chips, floating in a substance like vegetable oil. With a printer-like device, the electronic ink-coated material - which, according to researchers, could be just about any flat surface - is subjected to electrical impulses that act upon the white chips to make them display as light or dark-colored. A positive charge applied to an area on the top of the display medium causes the white chips to float to the top surface, and a charge applied to an area on the bottom of the medium causes them to drop to the bottom. The pattern of charges applied in concert enables the display of images and text. 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".
Lucent and E Ink are developing a device (also called E Ink) that 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 computer circuits onto the surface. Electronic ink has been used for simple displays, such as retail signs. Researchers say that more complex displays using the technology are still several years away.
Displays written in electronic ink are bi-stable: they remain fixed until another charge is applied to change them. Once you had read the first section of your electronic newspaper you would select the next section that you wanted to read, download it from a wireless Internet connection and have the paper automatically refreshed to display, for example, the arts or sports news that you wanted to read. Another expected application of electronic ink is a more book-like version of the e-book. Consisting of a similar number of e-paper pages, and having the same look and feel as a traditional book, the future technology would allow the reader to download book after book to the same physical device. E Ink claims that a device written with electronic ink could be rewritten as many as 300 million times.