An electronic paper display (EPD) is an electrically-charged surface that replicates the look and experience of ink on paper.
EPDs are extremely thin and only require power when a new image is requested. Instead of a traditional display that uses backlighting to illuminate pixels, an EPD is based on the scientific phenomena known as "electrophoresis," the movement of electrically charged molecules in an electric field.
Different manufacturers use closely-guarded methods to encapsulate the molecules and apply them to a substrate. E Ink, for instance, uses positively charged white particles and negatively charged black particles suspended in a clear encapsulated fluid. To form an electronic display, the encapsulated "ink" is printed onto a sheet of plastic film that is laminated to a layer of circuitry. The circuitry forms a pattern of pixels that can be controlled by a display driver.
When a negative electric field is applied, the white particles move to the top of the capsule, where they become visible to the user. This makes the surface appear white at that spot. At the same time, an opposite electric field pulls the black particles to the bottom of the capsules, where they are hidden. By reversing this process, the black particles appear at the top of the capsule and the surface appears dark at that spot.
EPDs are ideal for many consumer and industrial applications, including eNewspapers, smart cards, electronic shelf labels, transportation signage, eBook readers and cell phone screens. Esquire Magazine will run the first EPD magazine cover in its 75th anniversary issue in September 2008.
Learn more about IT:
> David DeJean wrote about the future of e-paper and electronic paper displays for Computerworld.
> Wikipedia's entry for electronic paper sheds more light on the future and technical background of EPDs.
> E Ink manufactures electronic paper displays.