Also known as electronic or e-paper, radio paper is a communication medium that has all the advantages of traditional paper, but can be reused indefinitely. The paper is actually a thin electronic display that utilizes electronic ink to provide a look that is very similar to a newspaper or a page of text from a book. Unlike text displays on conventional computer screens, radio paper does not make use of back lighting as part of the display process. The end result is that light is reflected by the surface of the display in a manner that is very much like a sheet of paper.
The earliest example of radio paper was developed during the decade of the 1970s. Using facilities owned by Xerox in Palo Alto, California, Nick Sheridan created a product known as Gyricon. This product made it possible to display images of static text on a silicone sheet treated with polyethylene spheres that carried a positive or negative charge. By subjecting the sheet to a series of charges at specified levels of voltage, it was possible to electronically write text on the front of the sheet, wipe the sheet clean, then write an entirely new set of text on that same sheet.
While various corporations continued to sponsor research that helped to enhance this basic process, the use of radio paper for mainstream purposes did not begin to appear until the beginning of the 21st century. Part of the reason for this is that the product has limited uses in comparison to other display methods. For example, radio paper does not have the capability to accommodate a rolling series of text in a manner that is common with LCD displays.
In spite of the limitations, e-paper is beginning to receive more attention. As early as 2006, several corporations released e-book readers that made use of radio paper technology. By 2007, a few had moved beyond a back lit approach to creating a display that reflected light in a manner similar to regular paper. During this same period, several European newspapers began to issue electronic versions that could be read using one or more brands of the e-text readers available at the time.
In 2007, the first efforts to create and issue textbooks using e-paper took place in Amsterdam. The motivation for the project was twofold. Using e-paper would reduce printing costs, which in turn would save the school district a great deal of money. At the same time, the books composed of radio paper would be much easier for students to carry, while still providing them with all the information necessary for successfully completing their studies.
Other applications of radio paper and electronic ink are appearing. Keyboard displays on handheld devices that use a combination of e-paper, electronic ink, and touch screen technology make it possible to change the mode of the keyboard display when and as necessary. Smart cards allow the creation of a single-use password to access financial accounts online, aiding in the effort to minimize online fraud and identity theft. Plans to incorporate the technology into digital photo frames are currently under development. As time goes on, other applications for electronic or radio paper are likely to appear and eventually be widely available to all consumers.