Phoenix — Although flexible-display technology is viewed in some circles as disruptive, its growth is being hindered by the absence of a compelling end application that would drive it into high-volume, cost-effective production.

Attendees at the Flexible Displays & Microelectronics Conference here last week saw a technology that is slowly clearing technical hurdles, but that is still seeking to carve a niche in a highly competitive display market.

Samsung Electronics Co. Ltd., for example, expects to launch a rugged plastic display by 2007. The display for mobile products will have a thin-film-transistor (TFT) amorphous silicon backplane and use existing liquid-crystal-display (LCD) production techniques.

"If we can adopt roll-to-roll processing, we believe manufacturing costs will come down," said Kyuha Chung, vice president of the Flat Panel Display R&D Team for Samsung's LCD Business.

Being able to fabricate displays in roll form is considered by many to be the most important step in achieving high-volume, low-cost production of flexible displays and microelectronics. Proponents say roll manufacturing would avoid some of the costly semiconductor-based fabrication processes used to make LCDs and plasma displays.

But not everyone is buying into roll manufacturing. "Investment costs are quite high for roll-to-roll processing," said Stuart Evans, chief executive of Plastic Logic Ltd. "Roll-to-roll may be essential for substrates but not for backplane transistors."

Plastic Logic is producing active-matrix polymer TFT arrays using direct-write printing and laser patterning, a process the company claims can easily be scaled to produce larger displays. The company is teaming with E Ink Corp., which supplies electrophoretic imaging media, to produce flexible displays. It is now installing a prototype line.

Taking a different tack, Rolltronics Corp. believes the obstacle to cost-effective flexible-display production is the semiconductor-based approach many suppliers are taking when they build them.

The company has developed a flexible thin-film microswitch backplane array, called the FASwitch, that it claims is far less expensive than silicon-based TFT arrays. According to chief scientist Nicholas Pasch, Rolltronics' technology is easily adaptable to existing flexible substrate production processes and does not require an investment in new equipment.

Aside from production methods, progress has also been made in improving the performance characteristics of substrate and barrier materials over the past year. But in many cases, these materials are not readily available.

A key remaining challenge in fabricating flexible displays is choosing a substrate with optimal temperature, gas-barrier and handling properties, said Samsung's Chung.

Beyond the technical issues, flexible-display technology will also have to present a more compelling economic case in a market where LCD technology dominates and continues to advance in price and performance.

"The real question is, "Do you want to go head-to-head with LCDs?' " said Willy Shih, president of the Displays and Components Group for Eastman Kodak Co.

Kodak is aiming for a niche approach to the market with its flexible-display technology based on cholesteric materials. The technology, which avoids complex processes like vacuum coating and photolithography, is intended for relatively low-tech, high-volume applications such as credit cards, tags and shelf labels.

Electronic ink or paper is also presenting a strong case for near-term commercialization. E Ink has moved its electrophoretic ink technology into production. The technology is used in Sony's eBook reader, according to Michael McCreary, E Ink's vice president of R&D.