Flexible Displays: Fascinating and Not As Far Off

by Paul Drzaic

A display fabricated on film is one of those ideas that has inspired both the general public and the display industry. Flexible displays of one sort or another are commonly found in science fiction and fantasy, most recently appearing in both the book and film versions of the Harry Potter series. Displays with flexible capabilities have been worked on for more than three decades within the display industry. They have certainly not suffered for lack of interest.

Nevertheless, flexible displays are not common in real-world applications. Most people would be hard-pressed to identify examples of flexible displays they have seen in real life. There are few other areas of display technology with such a lengthy gap between R&D demonstrations and commercial reality.

Part of the reason is that making flexible displays is difficult. Plastic films are not the ideal substrate for building highly precise electronics. Many displays are rather fragile, and plastic films do not provide the environmental protection that glass sheets do. It is also true that the dominant display technology, polarizer-based nematic liquid-crystal displays, do not work well in a flexible package.

A bigger challenge has been the success of mainstream active-matrix liquid-crystal display (AMLCD) devices. Every year, these displays improve in quality, shrink in cost, and find more and more applications. Expectations for displays grow more demanding every year. If consumers are going to give up quality, size, or low cost just to obtain a flexible display, there had better be a really good reason for the flexibility. To date, neither the industry nor the user community has been effective in identifying that flexible display "killer app."

Nevertheless, the pace of flexible-display development has been accelerating over the past few years. A number of factors are at play. New materials enable new types of devices. Large R&D organizations and universities associated with the display industry are putting unprecedented efforts into developing flexible electronic technologies. There is great creativity going on in identifying new uses for flexible displays, which is beginning to create the demand that has been lacking for so many years. With these thoughts in mind, this month's Information Display takes a look at some examples of flexible displays that just may make the leap from laboratory to widespread adoption.

Janglin Chen and Jia-Chong Ho describe how ITRI in Taiwan is developing a new process for fabricating high-resolution flexible displays. One of the problems in the development of flexible displays is the cost associated with scaling up new fabrication technologies. The work from ITRI describes an innovative way of using existing fabrication facilities to build flexible displays at high yield and low cost. This work was recognized by The Wall Street Journal, which awarded it a Gold Prize in its Technology Innovation Award competition.

I think it is important to consider that flexible displays may enable brand-new applications, rather than serving as flexible replacements for displays already in use. The paper by Asad Khan describes a number of emerging display applications, ranging from flexible electronic notepads to electronic "skins" for devices, that are enabled by the flexible-display technology developed at Kent Displays. If any surface can be turned into a display, then we have enabled the potential of making those surfaces smart and interactive.

The article by Hajime Yamaguchi, Tsuyoshi Hioki, Shuichi Uchikoga, and Isao Amemiya demonstrates a different approach, in which the flexibility of the electronic display enables a brand new type of interface. Toshiba has devised a prototype display in which display navigation is enabled by bending the display. If a bendable interface can be made intuitive and workable across multiple applications, then a flexible display can create new applications that have not yet even been imagined.

Will 2011 become the breakout year for flexible displays? Hard to tell. I can predict, though, that the innovative work showcased here, in the Journal of the SID, and during SID's Display Week, makes it likely that widespread adoption of flexible displays could be just around the corner.

I'll use this column to point out a major new review paper covering the current status of electronic paper, a field that overlaps greatly with flexible displays. The paper appears in the February 2011 issue of the Journal of the SID (JSID 19/2) and is entitled "A critical review of the present and future prospects for electronic paper." It is written by Professor Jason Heikenfeld (University of Cincinnati), Dr. Jong-Souk Yeo (most recently at Hewlett-Packard, but moving to Yonsei University), Dr. Tim Koch (Hewlett-Packard), and myself. If you have any interest at all in the field of electronic paper, please check out this article — I can guarantee you will find it worth your while. •