Display Tech To Watch This Year

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Display Tech To Watch This Year: OLED's Future Looks Bright

Right now Samsung owns the lion's share of the total market for OLEDs, most of which are used in small-screen devices such as smartphones. Samsung supplied nearly 90% of the 46 million displays that shipped in 2010, according to market researcher iSuppli. While other manufacturers have plants in the works, "Samsung is the only one in mass production," says analyst Vinita Jakhanwal.

With a new, $2 billion plant scheduled to come online later this year, the company will double its capacity, Jakhanwal adds. A spokesperson from Samsung's Mobile Display unit in South Korea says the company projects that it will grow shipments by a factor of 35, to 700 million units by 2015.

The next generation of displays certainly won't be big enough for television use, but the 5- to 7-in. screens likely to roll off Samsung's production lines later this year will be perfect for small tablet PCs such as Samsung's 7-in. Galaxy Tab, which currently uses an LCD screen.

Trouble spots

But can manufacturers overcome the obstacles to mass production of larger screens -- and more demanding applications? Even in smartphone-sized screens, OLED-based displays cost 20-50% more to produce than comparable LCDs, a cost that's usually passed on to the consumer, says Jennifer Colegrove, vice president of emerging display technologies at DisplaySearch. And at sizes larger than 10 inches, OLED displays can cost 500% more, she adds.

But Colegrove says that the technology has the potential to be cost competitive in the long term because the structure of an OLED display is simpler to build than an LCD.

OLEDs have another weakness: The lifespans of the organic materials that produce the red, green and blue colors vary -- a problem known as differential aging. The blue OLEDs are the problem.

For example, UDC's phosphorescent OLEDs, used in many manufacturers' OLED display designs, can produce green and red colors that last for "hundreds of thousands of hours," Mahon says. But the company doesn't have a viable blue product yet. So for blue, display manufacturers use a fluorescent OLED technology that lasts only about 50,000 hours.

Applications that use intense colors shorten color life faster, and those that use a blue background exacerbate the differential aging problem. Applications with a white background also cut down on display life and consume more power, since generating white light requires that the red, green and blue OLEDs all be on at the same time.

UDC's Mahon says that the current generation of OLED displays exceeds the requirements for mobile applications and is "sufficient" for TVs. But Samsung and other display manufacturers are pushing UDC and others to produce longer lasting blue OLEDs for TVs and other demanding applications. UDC is working on it, Mahon says, but so far the company has been unable to create a blue OLED that can pass the 50,000-hour mark.

Rigidly flexible

Assuming those obstacles can be overcome and larger-sized OLED displays can be produced in volume, manufacturers will look next at moving off of glass substrates for the TFT backplane and onto either flexible plastic or metal foil, both of which are thinner, lighter and more durable than glass.

Some researchers say flexible OLEDs could potentially cost less to manufacture than LCDs because they can use print-based "roll-to-roll" processes to embed the transistor arrays onto the substrate, rather than the traditional, discrete process, called mask alignment. (For details, see "Flexible displays: What's the holdup?")

Samsung, Sony and others have demonstrated flexible OLED display products, and UDC has been working with LG Display to supply prototypes to the U.S. Army and Air Force, which value the flexible backplane's durability.

Samsung demonstrated this flexible OLED display, housed in a rigid frame, at a trade show last fall. Source: Samsung.

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