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PCWorld.com - Apr 2003

1 Year Ago...

For the past couple of years electronics companies researching OLED, or Organic Light Emitting Diode, displays have been making technology promises that are almost as bright as the displays themselves, but commercial products have been lacking.

The first commercial OLED began shipping in March 2003. However, both it and the latest batch of prototypes suggest that the power-reduction promises made about the technology may have been optimistic, at least for the first generation of products.

OLEDs are a fundamentally different technology to LCDs. They are made by sandwiching a layer of organic material between two electric connectors. When a charge is applied to one connector it flows through the organic material, causing it to glow.

This means that, unlike an LCD, no backlight is needed and so the entire display panel can be made thinner, lighter, and will require less power than an equivalent LCD. At least, that's what was promised. Current prototypes, on display Wednesday in Tokyo at the Electronic Display Expo, consume around the same power as an LCD and in some cases more.

A prototype 2.1-inch panel from Seiko Epson consumes around 150 mW (milli Watts) when displaying a moving image. A thin film transistor LCD of a similar size consumes just over 150 mW with its backlight switched on, making the OLED power saving negligible.

"The technology is still young," said Tsutomu Takenouchi of Seiko Epson's OLED technology division. "We hope to improve the power saving with future generations."

Prototype versions of 2.2-inch and 3.5-inch panels were also displayed by Toshiba Matsushita Display Technology. Commercial production is scheduled to begin sometime in 2004, said Jun Hanari of the company's research and development center. On power consumption, he said that in some cases, such as a still screen of black text on a white background, it could be as much as double that of a modern LCD.

However, to write off OLED technology just because it doesn't live up to promises about power consumption would be to ignore its other features, and to dismiss a market that DisplaySearch estimates will reach $3 billion in 2007.

In addition to being physically smaller, the prototype displays on show in Tokyo on Wednesday were brighter, showed more vibrant colors, and were much better at displaying moving images than similar LCDs.

One of the biggest hurdles to commercialization for many companies is the length of time the display can be used before its organic structure breaks down, said David Hsieh, an analyst at DisplaySearch in Taiwan. The problem is that the organic layer slowly succumbs to a chemical reaction that eventually renders it useless, he said.

"The stability of the organic materials is not easy to control," said Hsieh, "but if the layers can be well controlled, OLED stability is will be achievable and then commercialization will follow."

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