Electronic Reusable Paper
Electronic reusable paper is a display material that has many of the properties of paper.  It stores an image, is viewed in reflective light, has a wide viewing angle, is flexible, and is relatively inexpensive. Unlike conventional paper, however, it is electrically writeable and erasable. Although projected to cost somewhat more than a normal piece of paper, a sheet of electronic reusable paper could be re-used 1000s of times.  This material has many potential applications in the field of information display including digital books, low-power portable displays, wall-sized displays, and fold-up displays.

Electronic reusable paper utilizes a display technology, invented at the Xerox Palo Alto Research Center (PARC), called "Gyricon." A Gyricon sheet is a thin layer of transparent plastic in which millions of small beads, somewhat like toner particles, are randomly dispersed. The beads, each contained in an oil-filled cavity, are free to rotate within those cavities. The beads are "bichromal," with hemispheres of two contrasting colors (e.g. black and white, red and white), and charged so they exhibit an electrical dipole. When voltage is applied to the surface of the sheet, the beads rotate to present one colored side to the viewer.  Voltages can be applied to the surface to create images such as text and pictures. The image will persist until new voltage patterns are applied.

There are many ways an image can be created in electronic reusable paper. For example, sheets can be fed into printer-like devices that will erase old images and create new images. Printer-like devices can be made so compact and inexpensive that you can imagine carrying one in a purse or briefcase at all times. One envisioned device, called a wand, could be pulled by hand across a sheet of electronic reusable paper to create an image. With a built-in input scanner, this wand becomes a hand-operated multi-function device -- a printer, copier, fax, and scanner, all in one.

For applications requiring more rapid and direct electronic update, the Gyricon material might be packaged with a simple electrode structure on the surface and used more like a traditional display. An electronic reusable paper display could be very thin and flexible. A collection of these displays could be bound into an electronic book. With the appropriate electronics stored in the spine of the book, pages could be updated at will to display different content.

For portable applications, an active matrix array may be used to rapidly update a partial- or full-page display, much like what is used in today's portable devices. Gyricon displays don't require backlighting or constant refreshing, and are brighter than today's reflective displays.  These attributes will lead to Gyricon's utilization in lightweight and lower-power applications.

Research into electronic reusable paper and its applications is continuing at Xerox PARC. Xerox is also pursing commercialization opportunities through the Xerox Venture Laboratory.

A Gyricon display, prototype printer and sheet of electronic reusable paper from Xerox PARC. larger jpg	This electronic reusable paper printing device may one day be small enough to fit into a purse. larger jpg	Small bichromal beads can be black and white or other contrasting colors. larger jpg

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The paper pulp of the future.

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Bichromal beads are at the heart of Xerox' electronic reusable paper.

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Xerox' partnership with 3M means electronic reusable paper can be manufactured in large enough quantities for commercial applications.

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Xerox PARC researcher Matt Howard demonstrates an active sheet of electronic reusable paper in the laboratory.

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Nick Sheridon, Xerox PARC inventor of electronic reusable paper, and Fereshteh Lesani show off the first roll produced by 3M partners.

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An electronically charged pencil rotates the bichromal beads in a sheet of Xerox' electronic reusable paper.

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