Flexible displays: What's the holdup?

A few manufacturing issues must still be overcome before devices with screens that flex, bend or roll up hit the mainstream.

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The biggest challenge with SAIL, Taussig says, is that it's an entirely new technology that doesn't leverage existing manufacturing infrastructure. "It is in a position much like the flat-panel industry was 15 or 20 years ago. Everything has to be built from scratch and new materials and processes developed," he says.

If roll-to-roll manufacturing of flexible displays does gain acceptance, Colaneri says, HP's technology could lead the way. To dramatically lower the cost of manufacturing, he says, "You need some out-of-the-box innovation like the one at HP Labs for manufacturing the transistor array without photolithography."

The challenge for technologies like SAIL, as Colaneri sees it, lies in pushing down the cost curve while providing sufficient benefits to convince manufacturers to make an investment in completely new fabrication facilities instead of retrofitting existing infrastructure. "Emerging display technologies have to come out at a price point [close to] what manufacturers can already buy the glass panels for," he says.

"I believe that the approach we are taking at HP Labs can change the game," Taussig responds. "Otherwise I wouldn't be betting my career on it."

Final challenges

Once the fabrication method and substrate material challenges are resolved, manufacturers will still face challenges adapting the display media to the flexible medium. E-paper technologies, such as E Ink's electrophoretic displays, can adapt readily. "We see that as the first flexible type display in the market," says Colaneri.

OLEDs, however, are sensitive to oxygen and moisture, and keeping a flexible OLED display sealed off from the environment while allowing it to flex is a tricky proposition. The OLED display medium, which emits light, also requires more current than does a liquid crystal medium, says Colaneri. That places a greater strain on the TFT circuits that drive the display media.

(While the OLED display medium itself consumes more power than an LCD, LCDs' reliance on a backlight makes them more power hungry overall. So in a fully constructed display, the OLED is more energy efficient.)

"It probably will require a change in transistor technology from amorphous silicon," Colaneri says. That's an investment. But in the TV market, the demand for very large, high-performance, high-definition displays is also causing the industry to search for an alternative, higher-performance transistor. "So there's a convergence between their needs and the needs of OLEDs."

Sony flexible OLEDs
Sony unveiled these bendable and rollable OLED displays as technology demonstrations at a trade show last May. Source: Sony.

There's one last hurdle on the road to mass-produced flexible displays: Nobody is quite sure what the killer app for them is just yet. Even if manufacturers can overcome the technical barriers and create displays that bend, flex or roll in volume, the significant investment in fabrication facilities required to produce them means flexible displays need a sizable market to move forward.

"The issue isn't whether you can make these things right now. It's whether you can manufacture them in a cost-effective way," says the FDC's Colaneri. Today, manufacturers are in a chicken and egg situation, he says. "How do you get something that doesn't have manufacturing economies of scale yet to that price point where it gets made and used?"

Until displays designed to bend and flex find a popular application, they are likely to remain one-off technology demonstrations seen only at trade shows. But that could change at any time. Consider that two years ago, prior to the launch of the iPad, the tablet PC was a technology searching for its niche. The applications are sure to come -- we just don't know what they are yet.

Next: Four red-hot display technologies to watch in 2011

Robert L. Mitchell is a national correspondent for Computerworld. Follow him on Twitter at twitter.com/rmitch, or e-mail him at rmitchell@computerworld.com.

Copyright © 2011 IDG Communications, Inc.

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