Will Your Next Display Be Flexible?

Thin, sleek monitors with bendable frames could become popular within a decade, according to researchers who gathered at the recent Flexible Displays & Electronics Conference 2004 in San Francisco.

Current displays are fairly rigid and more susceptible to breaking, while flexible displays will be lighter and durable, which increases their mobility and life span, says Kimberly Allen, director of technology and strategic research at iSuppli/Stanford Resources, based in El Segundo, California.

"We think of displays as fragile and are worried that they are going to crack." If displays were as flexible as our clothing, users would worry less about that, she says.

Flexible displays in different designs and shapes will change the way some consumers relate to visual information, she says. "Show them the display and they will get excited. Once you see it, you think, 'Yeah!'"

Fashionable Future?

The flexible display industry is developing rapidly, according to Patricia Kinzer, conference director for Portland, Maine-based Intertech, which organized the event. "It is moving into the wearable arena as well as handheld applications like PDAs and e-books," she says.

Interactive flexible displays could eventually be seen on jackets, bags, and other wearable fabrics, says Victoria Wedding Kurtz, vice president of Imaging Systems Technology, a Toledo, Ohio-based company researching plasma-based flexible display technology. The conference featured a flexible-display fashion show with models wearing jackets and other clothing, as well as jewelry.

Flexible displays first have to overcome scientific, manufacturing, and cost-related issues to be mass produced, says Peter Slikkerveer, a project leader at Philips Research in the Netherlands.

There are two products with flexible displays already available, but they are mostly of novelty value with limited capabilities, Allen says. One is an electrophoretic sign made by Gyricon. Electrophoretic displays involve placing black-and-white micron-sized particles in a fluid-filled space, after which a voltage is applied to give the particles a positive and negative charge. Colors are then produced by passing a filter, which is an array of particles that polarizes light to create color. The other product is a curved 3D LCD used by Nike in a watch.

Making such products is generally too expensive right now, Allen says. Mass consumer products with flexible displays will be available at the end of the decade at the earliest, she says.

Additional Uses

Applications for flexible displays are also being researched by the military, says John Burgos, a computer engineer for the U.S. Army's display technology team. Displays on a soldiers' uniform with PDA-like capabilities can inform them about enemy positions, weather, and environmental conditions. That could also help eliminate 10 pounds to 20 pounds worth of GPS (Global Positioning System) and communication equipment that a soldier carries, he says.

Other than a few products being tested, flexible displays remain mostly unproven with much of the work being done by researchers, Slikkerveer says. In addition to grappling with scientific issues, researchers are looking at how to improve the quality of displays while driving drown manufacturing costs.

Flexible displays are based on the same physics that govern the manufacturing of rigid screen monitors, says Carol Wedding, president of IST. "We are not changing the basic technology of physics," she says.

How to best flex the displays is also an issue, Kurtz says. Each different display technology has its advantages and disadvantages. Plastic and other polymers were the screens, or substrates, of choice for many flexible displays discussed at the conference, as they can be easily bent.

Flexible substrates using electrophoretic display technology could go to manufacturing within two to three years, says Allen. One product with an electrophoretic display that may be flexible in a couple of years is Sony's LIBRIe e-book reader, which was developed with Philips Research and E Ink, says Slikkerveer of Philips Research. LIBRIe currently publishes text on a glass-based rigid screen, which looks like ink on paper. He envisions future LIBRIes to be as flexible as paper.

Technical Challenges

The scientific challenge of using LCD technology is in making the flexible display work effectively, Allen says. LCD technology works well for rigid displays because the backlight and substrates remain constant, making it easier to apply color filters to create images. Flexing them both causes image quality to deteriorate, which is why researchers are facing challenges in creating flexible LCDs, she says.

OLEDs (organic light-emitting display) with flexible polymer substrates could be a better choice for creating flexible displays, as they are more amenable to flexing than traditional LEDs. However, they could easily let water through, so they would need a barrier layer for protection, she says. OLEDs, which can already be seen on glass-based cell phone and car stereo displays, involve the emission of light after voltage is applied to a molecule, which spits out red, green, and blue protons, Allen says.

Other emerging flexible display technologies were also discussed at the conference, like IST's Plasma-sphere Display, a plasma-based flexible display. IST hopes to improve on conventional plasma TV screens by passing 150 to 200 volts of electricity to spheres encapsulating ionizable gas that will create images on flexible substrates. "It is not meant for displays you wear on your wrist," says IST's Wedding, as the voltage it passes is too high.

IST has been researching the technology for about a year. "We should have a monochrome prototype in about a year and a color prototype in about two years," she says, adding that "we first have to prove the technology, then we can drive down the cost."

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