HDTV TECH

Plasma and LCD are dead. Well, at least that's what Kodak, Dupont, Universal Display Corporation, and a few others would like you to start thinking. One of the new technologies coming down the HT highway is called Organic Light Emitting Diode (OLED), and it could be the future of flat-panel displays. Soon your TV may be able to trace its lineage back to the power light on your VCR.

Functionally, OLED is as similar to plasma and LCD as it is different. Like LCD, OLED comes in two flavors: passive and active. The active version is the one we care about, as it allows for accurate video display. An active OLED, like an active-matrix LCD, uses thin film transistors (TFTs) to regulate power to each pixel directly. Each pixel gives off its own light when supplied with electricity, which is more like plasma.

Unlike plasma, the OLED substances (which have names like substituted dinapthyl anthracene and quinacridones) emit the light themselves, as opposed to the excited plasma emitting UV while a separate phosphor emits the visible light in response. This electroluminescence means that OLEDs don't need the power-hungry backlight of LCDs. Both of these factors mean that OLEDs require significantly less power than either of the other technologies.

You Don't Know Thin
OLEDs can also be really thin. How thin? You could stack several of them on top of each other, and they still wouldn't be as thick as this magazine. Even better, nothing in the technology or manufacturing process puts a limit on screen size or resolution. So now you're thinking about an OLED that's as big as the biggest plasma, but thinner and lighter. Think bigger. How about an OLED to replace your projection screen? Bigger. How about an OLED to replace your wall (not structurally, of course)? Now that's a big screen.

That's not all. OLED offers even more possibilities. There's Flexible OLED (FOLED): Imagine a TV you can roll up like a newspaper or wrap around your arm. Then there's Transparent OLED (TOLED): Picture a TV on the windshield of your car. Won't that be great for the morning commute? (Other drivers will be so jealous as you plow into them while watching Spiderman 4 on your in-car HD DVD player.) More realistically, it could be used to superimpose a map that's linked to your car's GPS to tell you where you are and where you're going. Or maybe it could turn your eyeglasses into your own private movie screen.

Perfect?
OLED isn't on the market yet for a few reasons. Color is the first. At the moment, the different-colored OLEDs age differently. So, over time, the picture will lose blue (the fastest to age). A red-and-green-only display isn't much fun to watch. Similarly, OLED's overall life span varies greatly depending on how you use it. If you were to run your OLED at its maximum light output all the time, it wouldn't live nearly as long as the same OLED running at half its total light output. As you might imagine, though, these aren't likely to be insurmountable problems.

The amusing thing is, you may not have to wait for OLED, at least on a small scale. You might even have one already. Some new cell phones, digital cameras, and car radios use OLEDs instead of LCDs because they require so much less power. Unfortunately, full-size OLED displays are, at best, years away. But a guy can dream, can't he?

Images courtesy of Kodak and Universal Display Corporation