Don't stop the paper presses just yet

For several decades, we've seen predictions that electronic technologies will bring about a much-needed reduction in the paper that swamps us at work and at home. The photocopier and the personal computer appear to have made the problem worse rather than better.

I know several quite technologically literate executives who routinely print their e-mails before answering them. Then the printed e-mails are photocopied for circulation to others. The paperless office is a chimera, at best.

But, I've been following the developments in electronic ink with some interest in the hope that, eventually, we'll see paper-like electronic documents that will satisfy even the most technology-phobic readers. Recently, E Ink Corp. (Cambridge, MA) and Lucent Technologies (Murray Hill, NJ) announced a milestone in their effort to develop a flexible, paper-like electronic display, jointly demonstrating working prototypes built on thin sheets of plastic (see p. 16). But you won't be able to buy electronic paper at Staples for some time yet.

Produced a year after the joint development project was announced, these paper-like devices may finally prove that electronic ink, driven by printed plastic circuits, is a compelling technology for electronic paper and other next-generation displays.

The prototypes consist of a 25-square-inch display area made up of several hundred pixels. The displays were constructed using two developments: E Ink's electronic ink and Lucent's active-matrix drive circuits printed on plastic, which were developed by Bell Labs, Lucent's research and development unit. The transistors in these circuits are made of plastic materials and are fabricated with a low-cost printing process that uses high-resolution rubber stamps. Their switching properties are similar to typical thin-film transistors made with silicon and conventional fabrication methods, but they are mechanically flexible, rugged and lightweight. The electronic ink enables the display's paper-like qualities: good brightness and contrast under a wide range of lighting conditions, easy viewing from all angles, low power consumption, and plastic film construction.

Getting closer to electronic paper
"True electronic paper has, in many ways, seemed like a futuristic technology," said Jim Iuliano, president and CEO of E Ink. "We have brought that concept closer to reality by demonstrating that electronic ink works with Lucent's flexible plastic transistors. With this combination of technologies we believe that we have found a very promising means for achieving paper-like electronic displays."

The ability of the materials to be printed on flexible substrates offers the potential to simultaneously reach the lower costs of flat panel displays and achieve paper-like form, look, and ease-of-use. But achieving the precise and attractive look-and-feel of the small fonts used in paper documents may be some years away.

Bell Labs researchers produced the plastic circuits for driving the electronic ink display by using newly-developed high-resolution rubber stamping techniques with associated compatible materials technologies that bypass many of the steps and costs involved in making traditional silicon devices. These methods also have the advantages of being compatible with rapid reel-to-reel printing schemes and they allow patterns to be applied to large sheets of plastic in a single step.

Brighter than a newspaper
The prototype displays demonstrate other paper-like qualities. Unlike conventional LCDs and other kinds of reflective displays, an electronic ink display is bright and is readily viewable under both bright and dim lighting conditions. Its contrast ratio of more than 10 to 1 exceeds that of newspapers, which typically have a contrast ratio of 8 to 1 or less. Because of its bi-stable and reflective nature and because it only needs to be powered during a switching cycle, the flexible display draws only 1/10 to 1/1000 the power of an LCD of equivalent size. The initial prototype can display both text and simple graphic images while being flexed. E Ink and Lucent expect displays incorporating printed plastic transistors could be available within five years.

Apparently, conventional offset printing is not about to go the way of the buggy whip. Electronic ink technology is proving to be effective for large displays such as airline arrival and departure announcements, but not yet for paper-like documents, so we are going to see more paper rather than less in the near future.