The end of paper

The recent invention of electronic ink promises to bring with it an electronic display medium that is inexpensive, flexible, can be printed on curved surfaces, and is as easy to read as ink on paper. Because of its unique properties, designers can use electronic ink displays in places where it was never possible to put a display. And, because it has the familiar form-factor of paper and the power of a digital display, it will ultimately provide a whole new display medium.

The developer of this new technology, E-Ink, is poised to create displays for hundreds of applications. The company claims that soon electronic ink signs will communicate with consumers at retail stores, banks and other consumer venues. As early as next year, electronic ink-based displays will start to appear in consumer electronics such as PDAs, pagers, cell-phones and wristwatches. Over the long term, the use of electronic ink technology can put displays into any place, at any time and on any medium, creating flexible displays, newspapers that typeset themselves and even electronic books.

Electronic ink is a fusion of chemistry, physics and electronics that creates a whole new material. At the foundation, electronic ink is made up of millions of tiny microcapsules suspended in a liquid. Inside each capsule is a mixture of dye and pigment chips. These tiny pigment chips react to an electric charge causing the display to change colour.

To illustrate electronic ink microcapsules, consider a clear plastic beach ball. Inside the beach ball are several dozen white ping-pong balls. And instead of air, the beach ball is filled with dark blue-coloured water. If you looked at the beach ball from the top, you would see lots of white ping-pong balls suspended in the liquid, and the beach ball would appear white. From the bottom, you would only see the dark blue water and the beach ball would look black. If you put thousands of these beach balls onto a field and could make the ping-pong balls move between the top of the beach balls and the bottom, you would make the field change colour.

In reality, however, the beach balls are microcapsules that are about 100 micro m wide. In a square inch, there are roughly 100,000 microcapsules. If this page were printed in electronic ink, the full stop at the end of this sentence would contain more than 30 microcapsules.

All existing display technologies are compromises. Paper and ink, while having a superior form-factor and readability, is static and unchanging. Existing electronic displays are limited by being hard to read, flat, expensive to make and power-intensive.

Electronic ink-based digital displays, on the other hand, combine the benefits of ink on paper with the dynamics of a digital display. The most significant benefit is in readability. Other displays must compromise readability and clarity. Electronic ink has superior reflectivity and contrast. Because it looks like ink on paper, it is a comfortable medium for people to read and handle. Moreover, in bright light where other displays wash out and become hard to read, electronic ink actually becomes easier to read. Finally, because the electronic ink microcapsules are so small, resolution is very good.

Electronic inks also sport low power usage. While other display technologies require a constant source of energy to hold their image in place, electronic ink requires only a tiny amount of power and only when it is time to actually change the display. Displays made with electronic ink are highly attractive in applications that require batteries or would run up large power bills.