Mar 31 2009

Nimble View

Flexible electronic displays create the possibility for users to tote lighter, greener devices than now available.

A plastic display as thin as paper? With real-world potential uses? And a friendly price tag?

Yes, yes, and yes, say Hewlett-Packard and the federally funded Flexible Display Center at Arizona State University. The pair recently unveiled what they dub the first affordable, flexible electronic display. The HP and FDC made the prototype predominately of plastic, which makes the device portable and more energy efficient than most conventional computer displays. Creation of the high-resolution flexible display marks a milestone for both HP and the FDC: the possibility of mass-market thin-display products.

“The display HP has created with the FDC proves the technology and demonstrates the remarkable innovation we’re bringing to the rapidly growing display market, while providing a lower-cost process,” says Carl Taussig, director of the Information Surfaces Lab at HP Labs.

Taussig says the self-aligned imprint lithography (SAIL) technology represents a more sustainable, environmentally sensitive approach to producing electronic displays.

Flexible electronic display technology portends a new generation of portable devices, such as e-books and e-readers. E-readers could have a significant influence on many markets. For instance, Veterans Affairs Department doctors could use them in hospitals for storing and retrieving patients’ medical records; or Defense Department engineers could use them as digital manuals, replacing heavy space-consuming paper documents.

E-readers also have the advantage of being interactive. Searching for a word in a book or a manual is quite complicated without an index, and even with a good index it can be hard. An e-reader can easily search text documents, and some e-readers also allow adding notes using a touch screen, which further extends their usefulness.

Vinita Jakhanwal, principal analyst for small and medium displays at iSuppli, expects the flexible display market to grow to $2.8 billion by 2013. Jakhanwal adds that the Flexible Display Center at ASU is a key participant in helping to develop the technology as well as a manufacturing ecosystem to support a flexible display market.

Beyond the Printed Word

The new flexible electronic display technology could be applied to electronic paper and signage, too. Mass production could enable displays to be used in notebook computers, smart phones and other electronic devices at a much lower cost than conventional display devices. Another major advantage is that these flexible displays use only 10 percent of the materials required by current display production, saving the environment and creating lighter devices.

The process of manufacturing the display starts with FDC producing stacks of semiconductor materials and metals on flexible Teonex, a polyethylene-naphthalate substrate. Using the patented SAIL process, HP patterns the substrates and incorporates E Ink’s Vizplex imaging film to create an actively addressed flexible display on plastic. The Vizplex is a bi-stable electrophoretic imaging film, which allows continuous display of images even when no voltage is applied. This considerably lessens a display’s power consumption, which in turn reduces electrical costs and provides for longer battery life.

HP Labs invented the SAIL process that proved crucial the successful creation of displays. The self-aligned element in this method is derived from patterning information, which is imprinted on the substrate in such a way that precise alignment is preserved, regardless of process-induced distortion. SAIL technology helps foster the manufacturing of thin-film transistor arrays on a flexible plastic material in a low-cost, roll-to-roll manufacturing process. This allows for more commercially continuous production, rather than batch sheet-to-sheet production.