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 Ever since that Philips commercial where a European-looking couple try hanging their thin TV in every room of a minimalist apartment, finally settling for a spot on the ceiling above the bed, plasma sets have been creating a stir. From airports to movie theaters to corporate boardrooms, these slimmed-down big-screen TVs draw stares from almost everybody.
Gas Works
The idea of using plasma gas to produce an image has been around since before those Euro-looking actors were even born. And flat-panel TVs have been on everybody’s wish list since they came to symbolize the home of the future back in the 1950s. Plasma panels were co-invented by University of Illinois professors Don Bitzer and Gene Slottow in 1964. Bitzer assigned one of his promising students, Larry Weber, to study the tiny gas-filled chambers, or cells, at the heart of the panel. Companies like IBM soon recognized the potential of the technology and began their own research. Weber eventually founded a company called Plasmaco to develop and market plasma displays. Plasmaco produced 10-inch monochrome screens for computer makers in 1989, followed by a 21-inch screen in 1991. Five years later, soon after demonstrating a working color panel, Plasmaco was bought by Matsushita. Unlike traditional cathode-ray tube (CRT) technology, which uses an electron beam to excite the colored phosphors that produce an image, plasma panels rely on ultraviolet light emitted by highly ionized gas to activate the phosphors. In this plasma state, the gas has a roughly equal number of positive ions and free electrons, making it an excellent conductor of electricity. Each panel consists of a few million tiny glass cells that contain the gas along with a red, green, or blue phosphor. Three cells, one for each color, combine to form one pixel, or picture element. A single panel can contain a million or more pixels, and screen sizes range from 32 to 63 inches (diagonal). Smaller sizes are feasible, and manufacturers are also experimenting with displays up to 72 inches. Plasma TVs are usually widescreen, with the 16:9 aspect ratio used in high-definition TV (HDTV), but our shopping guide at the end of this article lists one model with a standard-shape 4:3 panel. Plasma monitors are jacks-of-all-trades. They can typically handle computer images, analog TV in both the American (NTSC) and European (PAL or SECAM) formats, and digital TV. Many can also display high-definition programs. Only a few have built-in TV tuners (although that’s changing) or sound systems. The major advantage of plasma over a traditional picture tube, aside from its superiority as a status symbol, is size. A large-screen CRT set needs a deep cabinet to house its electron gun. The average 36-inch TV is about 2 feet from front to back and weighs more than 200 pounds (try hanging that on your wall). A plasma monitor, thanks to those self-contained imaging cells, is only a few inches deep regardless of its screen size. Most 42-inch plasma sets are around 31¼2 inches thin and weigh less than 70 pounds. And plasma TVs can have significantly larger screens than CRT-based direct-view sets, which are limited to a maximum of 40 inches or so. Indeed, plasma might be the ideal display technology for home theater. Unlike projection setups, front or rear, which you have to watch in a dim room, plasma TVs look fine over a wide viewing angle in normal room lighting. Their slimness makes installation a matter of clearing enough wall space. Custom installations can involve a plasma screen centered above a mantelpiece or sliding down from the ceiling — one inventive design mounts the display inside a transparent glass wall that swivels between two rooms.
Getting the Picture
The video signal processors inside plasma TVs have to do a lot of work to match the resolution of the incoming programs — in either a standard or high-definition format — to the panel’s fixed number of pixels (its native resolution). In most cases the signal has to be de-interlaced and converted for display, a process known as scaling. Since the resolution of standard TV is fairly low, it needs to be scaled up to fit the pixel count in plasma sets. Material in the most commonly used HDTV format, 1080i (interlaced) — which has a 1,920 x 1,080 pixel count — must be scaled down to fit the native resolution even of high-end plasma sets, which sacrifices some picture detail. The other high-definition format, 720p (progressive), requires a panel with at least 1,280 x 720 pixels to avoid reducing image quality. But no video signal format has a resolution of 1,024 x 1,024 pixels, so a panel with that pixel count needs to have all incoming video scaled.  Scaling isn’t a problem as long as the processor does a good job, and some built-in scalers work fine. Still, people who want the best video performance often attach outboard processors to scale and otherwise process the video signal before it reaches the plasma panel. Outboard processors are available from a number of companies, including Faroudja, Runco, and Vidikron. Plasma displays are generally excellent at handling computer signals, which can be modified at the source (for example, the PC’s video card) to match the panel’s pixel count. DVDs look great even on lower-priced widescreen plasma TVs because the native resolution of such panels — 852 x 480 pixels — exactly matches the specification for widescreen DVD. But panels with higher resolution and good scalers can make both DVDs and other video sources look even better. The other flat-panel technology — LCD, or liquid-crystal display — would seem to provide the same benefits as plasma. But LCD screens tend to run smaller than their gas-powered brethren since large-screen LCDs are even more expensive to produce than plasma displays.
What Price Plasma?
A couple of factors contribute to the high price of plasma. The first is the difficulty of making the glass — including those millions of tiny cells — for plasma panels, which is done by only a handful of companies, including Panasonic, Pioneer, Fujitsu, Hitachi, and NEC. In fact, the process is so tricky that today’s manufacturing plants recycle 20% to 50% of their finished panels because the delicate glass is flawed in some way, according to Matt Dever, vice president of product planning for Pioneer. The second has to do with economies of scale. The specialized components needed to make plasma TVs are expensive because relatively few are made. This leads the set manufacturers to charge high prices to recoup their costs, which means relatively few people can afford to buy plasma sets. Low sales numbers give the component makers little incentive to ramp up production to make more components available at lower prices. Both of these problems have begun to disappear as consumer demand and manufacturing know-how have grown, but the top manufacturers agree that traditional picture tubes will continue to dominate the TV market for at least the next few years. “Everybody who’s ever said something like this has been proven wrong, but I’ll say it anyway: plasma TV is never going to be inexpensive,” says Sam Runco, CEO of high-end manufacturer Runco. Like any groundbreaking technology, plasma will need some time before it becomes both familiar and affordable enough to be taken for granted. Today, only a privileged few can lie down and watch late-night TV on the ceiling. But tomorrow, the breakneck pace of technological advancement, coupled with the inevitable drop in prices, will mean that a lot more people will be able to own an ultra-thin, high-performance, big-screen plasma TV set.
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