Electronic paper has many of the properties of paper; thin, flexible, and readable from a wide angle, but it also has the distinct advantage of being reusable.
In the 1970s Xerox PARC had developed a personal computer, and Nicholas K. Sheridon had the task of developing a display that improved on the then very dimly lit cathode ray displays. In 1974 Sheridon developed the Gyricon, which—although it was never used as a monitor because the PC project was dropped—formed the foundations of e-paper.
The Gyricon, Greek for rotating image, consists of a thin, flexible sheet of plastic peppered with oil-filled wells containing small beads. Each bead, colored white on one half and a contrasting color (usually black) on the other, is charged with positive and negative ends that corresponded to the two colors. When an electrical current is applied to the Gyricon, the beads rotate in a predicted manner displaying their black sides where marks are to be made on the paper. A major advantage of this type of display is that once the initial current is applied no further energy input is required to maintain or refresh the image.
Today several types of e-paper have been produced, such as the bistable LCD (liquid crystal display), cholesteric LCD, and the electrophoretic display, which works on a similar principle to the Gyricon and has also been developed to display color. Initially highly expensive, the cost of e-paper continues to decline and has already started to appear on the market. It is predicted that e-paper will be everywhere, from billboards, to schools, and even at home as a changeable wallpaper, within the next decade.
