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Flat Panels: Thin Is In

Last month, I covered several significant product and technology announcements at CES 2005. While much of the press coverage of this show focused on such oddities as Samsung's 102-inch plasma TV, there were less obvious but far more important exhibits worth a second, more detailed look.

You're probably wondering just how reliable an LED backlight would be in the long run. The industry-accepted life cycle for LEDs is between 50,000 and 100,000 hours, so it's not unreasonable to assume you'd get rid of an LED-equipped LCD TV long before it reached half brightness.

Incidentally, LumiLEDs also figured into other demonstrations of “pocket” projectors at CES in the InFocus and BenQ booths. No one could say for sure just how much light you'd get out of one of these tiny boxes (best guess is 30 to 40 lumens), but the concept was certainly an eye-opener.

The world of tomorrow

Over in the South Hall of the Las Vegas Convention Center, Toshiba held some private demonstrations of the SED, and believe me, it was difficult to gain access to this demo. But once inside, the experience was well worth it. The prototype SED shown was a 36-inch model with 1280x768 resolution, and mounted alongside it were a 40-inch LCD TV and a 42-inch plasma monitor.

It wasn't a fair fight, although the Toshiba people admitted they made no attempt to calibrate the plasma and LCD monitors for this shoot out. The SED won hands down — it had no discernable motion artifacts, exhibited deep, rich colors, a super-dark level of black, and plenty of image detail and contrast. Plus, it used much less power in doing all of this, if you believed the large, green LED display of real-time power consumption included in the demo.

The concept behind the SED is similar to that of a CRT. Electrodes along the backplane of the display emit electrons when they're switched into a conductive state. These electrons are attracted to the front of the SED (which you could consider to be the functional equivalent of an anode) by a high-voltage potential, somewhere around 10 kV.

The front glass is coated with tiny red, green, and blue phosphors just like a CRT. The electrons are accelerated to very high speeds and strike each individual phosphor, causing it to glow brightly. Because the emitters (or cathodes) are aligned precisely with the phosphors, there's no need for any deflection yokes. That makes for a much more compact and lighter display. It's pretty bright, too. Toshiba claims the SED can achieve 10,000:1 contrast in a darkened room, but at that number I'll bet the grayscale images would be bloomed out and crushed.

Still, this technology has lots of potential, if it can be brought to market quickly enough at competitive prices and in multiple screen sizes. (Toshiba representatives talked about a 50-inch design with 1920x1080 resolution as the most likely 1st-generation commercial product.) If not, then SED may get lost in the crush of lower-priced, dime-a-dozen LCD and plasma TVs and monitors flooding the market. (And that wouldn't be the first time that a superior technology lost the race — remember Betamax and VHS?).

The groove tube

Fujitsu chose to avoid the hubbub of the convention center and opted for a comfortable suite at the Venetian, in which it managed to tuck numerous plasma monitors, its brand-new 1920x1080 HTSP LCD front projector, and a small exhibit on the plasma tube.

The plasma tube concept is pretty revolutionary. Individual tubes, measuring 1 meter long and 1 millimeter in diameter, contain individual red, green, and blue phosphors. These tubes are then sandwiched between electrode plates, which are manufactured separately (and less expensively, too).

The chief advantage to this process is a substantial reduction in weight of the finished plasma monitor, which could allow for much larger sizes to be manufactured. But there's another aspect to consider — the flexibility of the plasma tubes. They can be bent to allow the construction of a curved display, something that's just not possible with conventional plasma architecture.

The luminous efficiency of plasma tubes is supposed to be far greater than that of conventional rib and deep pixel structures, and Fujitsu's target is to achieve 5 lumens per watt of energy used. That means it would be possible to build a 100-inch plasma display that would consume less power than today's 42-inch panels. According to Fujitsu, the costs and complexity of plasma manufacturing would both come down as no clean room is required. The tubes would be manufactured in long sections and simply mated to the electrode-bonded mother glass in whatever screen size is desired (can you say tiled display?).

Given the reduced power consumption of the tube design, it's possible that the current king of large emissive displays —the LED — could be knocked off its throne in the not-too-distant future. Plasma tubes aren't ready for prime time now, but you should start to see demonstrations of workable product designs within two years.

Pete Putman is a contributing editor for Pro AV and president of ROAM Consulting, Doylestown, PA. Especially well known for the product testing/development services he provides manufacturers of projectors, monitors, integrated TVs, and display interfaces, he has also authored hundreds of technical articles, reviews, and columns for industry trade and consumer magazines over the last two decades. You can reach him at

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