Through Thick and Thin

Back to Contents of Issue: March 2001

A new cellphone screen uses organic compounds to create amazing colors on a superthin screen.

by Michael Thuresson

THE CELLPHONE is an organic part of life here -- and now organic matter is a part of the cellphone. A Japan-Korea joint venture called Samsung NEC Mobile Display is incorporating organic compounds into keitai screens, resulting in radiant screens with less bulk, glare, battery drain, and manufacturing cost.

With video, animated graphics, and other multimedia services dialing in to the wireless Web here, the limitations of traditional liquid crystal displays -- aka LCDs -- have become painfully evident, forcing screen makers to explore new areas of research, including the natural sciences. This has led to the realization that organic electroluminescence -- used by many forms of life to emit light -- offers a way to create superior small screens.

cellphone display
It was difficult to reproduce the screen's image here, but, trust us, it looks great, especially considering how thin it is -- see left. It's hard to imagine cellphone screens getting any thinner than this, unless they were made of electronic cardboard.
"Because of its self-emitting properties, organic EL can transmit light at a very high speed, in a full-color range, while using less energy," says Kenji Okada, division manager of NEC Display Device Development. "It transmits video at about 1,000 times the speed of LCD."

How does it work? The display is composed of a thin organic layer sandwiched between two metallic plates. The organic (i.e. carbon-containing) material emulates the self-luminescent characteristics of certain organic tissues present in some living creatures. When an electric charge is applied to the metallic plates and across the organic layer, light is instantly emitted.

"It's the same principle as the firefly," explains Okada. "Its organic matter is not inherently glowing -- it takes a jolt of electrons to display the natural luminescence of its matter."

In comparison, an LCD derives its luminescence from a backlight that emits light through a layer of liquid crystals. The crystals, switched on or off by an applied voltage, determine the light intensity and color mixture of the image displayed by the screen's pixels -- a slow, battery-sapping process.

Within EL screens are blue, green, and red organic materials, and from these any color can be derived and placed within a single pixel. The result is incredibly bright and readable images.

There's also no glare. Unlike an LCD, which tends to retain outside light, no ambient light can penetrate an organic EL screen. This also allows for a wider viewing angle (not necessarily a privacy improvement). And since the only light is that emitted from the organic layer, the contrast is amazing and looks equally good in dim corridors, outdoor cafes, and darkness.

The screen -- we're gushing, we know -- also allows for a more compact handset. The Samsung NEC prototype has a 2.2-inch screen and is only 2.3-mm thick, making current mobile phones look downright primitive. And because of a simpler manufacturing process, organic EL phones, when they hit high-volume production, are predicted to be cheaper than current LCD ones.

Surprisingly, EL technology has already been used in a few commercial products. Eastman Kodak patented the display technology in 1987 (and receives royalties from anyone producing organic EL displays). Motorola introduced an "area color" phone in the US last fall that only partially derived colors through organic luminescence. "It sold very well despite a high price," says Okada. "That lesson is not lost on us."

But the technology seems especially well suited to Japan's booming wireless Web (and to a lesser extent, other parts of Asia). With the country's unrivaled passion for mobile communications, it's likely that consumers here will quickly embrace these dramatic display improvements, which gives Samsung NEC Mobile Display the look of a winner.

The company, a partnership between Korea's Samsung and Japan's NEC, expects commercialization of the screens to begin next year. In the meantime, it's cranking out some 700,000 of the displays for handset manufacturers each month. It expects organic EL screens will comprise 30 to 40 percent of the 3G mobile display market by 2005 -- by which time we, at least, think cellphone videochats will be common in Japan.

Time will tell if organic displays are the future, but one thing we do know: this is the right country to find out in.

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