主题：【文摘】NYTIMES: Sharpening Plasma's Image (in English) -- raindrops

(A worker at the Samsung booth at the Las Vegas electronics show displayed an L.C.D. monitor next to the company's largest plasma set.)

March 3, 2005

Sharpening Plasma's Image

By ERIC A. TAUB

IF ever a product evoked lust in the heart, it is a plasma television. Like radial tires in the 1970's, a big flat plasma set is today's must-have technology.

But whispers about the plasma set's shortcomings - some old, some new - have increased recently. Critics have focused on the technology's warts, comparing its performance unfavorably with that of liquid-crystal displays, another flat-screen technology.

If the negatives stick, it may mean trouble for LG Electronics, Panasonic, Philips, Samsung and Sony, all companies that continue to invest billions of dollars to produce plasma and L.C.D. sets.

To address questions about plasma's image quality, life span, power consumption and other characteristics, several of these companies have started campaigns to change public opinion.

"The early versions of plasma had some issues, like product life and image burn-in," said Jeff Cove, vice president and general manager for Panasonic's consumer electronics group. "But old news is coloring how people perceive the product. It was absolutely not affecting the business, but it could affect it."

Samsung is hearing the whispers as well. "We have significant stakes in both businesses, and plasma is getting the short shrift," said Jim Sanduski, vice president for marketing of the company's visual display products group.

Larry Weber, one of the inventors of plasma technology, said that recent publicity, right or wrong, about how L.C.D. sets would eventually take over the large-screen market could only hurt plasma sales. "It makes sense that plasma companies should speak out," he said.

And so they are. At the Consumer Electronics Show in January in Las Vegas, Panasonic executives conducted side-by-side demonstrations of the two technologies, in which criticism of the plasma set's performance was systematically rebutted.

In casual conversations, the presidents of Panasonic, the world's top-selling plasma brand, and Samsung, which ranks third, promoted their strong commitment to plasma, even though no one was actually asking.

The problem is that once a product's reputation falls in a hole, it is not so easy to get it out. "You hear blatant lies about plasma," said Danielle Levitas, a senior analyst at IDC, a research firm.

Faced with whispers of plasma's faults on one hand and a vigorous defense by manufacturers on the other, what is a consumer to do?

A potential flat-screen buyer could look at two sets, side by side, and decide which one is better: plasma, which has thousands of tiny gas tubes that light up to create pixels, or L.C.D., which has a constant light source and uses the crystals to let varying amounts of light through for each pixel.

But a video picture that looks great in the showroom may look terrible at home, or vice versa. "TV's are shipped with the brightness and contrast maxed out," said Gerard Catapano, manager of testing in the electronics division for Consumer Reports. "The manufacturers want you to be wowed by it, so the visual characteristics are peaked."

There are objective ways to compare the performance of L.C.D. and plasma sets. Here are some of the differences between the two.

Screen Size

Plasma sets are not made in sizes smaller than about 37 inches because it is too difficult to squeeze a large number of plasma pixels into a smaller screen. Making L.C.D. sets in sizes larger than about 32 inches has not been economical because factories have not been able to create several larger viewing panels from one piece of glass.

But new plants, which can produce multiple L.C.D. screens from a single sheet of glass, are starting to operate. As part of a venture between Samsung and Sony, a new plant will be able to produce 40-inch L.C.D. sets in the spring. In October 2006, Sharp will open a plant designed to produce 45- and 50-inch L.C.D. sets, sizes that plasma offers.

All the new production capability should mean a continuing drop in prices for L.C.D. sets. A 42-inch L.C.D. set that cost $4,500 last year will fall to $1,700 by 2008, said Ross Young, president of DisplaySearch, a company that researches flat panel sets.

Prices for plasma sets should decline as well. Last year a typical 42-inch high-definition model cost about $4,200. By 2008 it should cost about $1,800, not much more than an L.C.D. of the same size.

"The challenge for plasma is that it has a fairly narrow sweet spot," said Greg Gudorf, vice president for television marketing for Sony Electronics. Above 50 inches, rear-projection sets that use Digital Light Processing or other technologies can be more attractive to consumers because they are less expensive without much of a difference in picture quality, Mr. Gudorf said.

Resolution

To keep plasma prices down, some manufacturers have been selling what they call enhanced definition sets rather than true high-definition models. Each receives a high-definition television signal, but the enhanced definition model has fewer pixels, and thus lower resolution.

But even most high-definition plasma sets have a lower resolution than an L.C.D. set. The image may look as sharp, however, depending on distance from the set. From an average viewing distance of 10 feet, Mr. Weber said, the eye cannot distinguish pixels that are smaller than about a millimeter. So making them smaller to squeeze more into a given area will not necessarily improve the picture quality. At 10 feet, a 42-inch high-definition plasma display has an adequate resolution, Mr. Weber said.

But as with high-powered cars, people want performance whether they need it or not. So some people opt for the higher resolution numbers of L.C.D. sets, even if it is hard to tell the difference.

Contrast

To look good, a television image needs to display a true white and a deep black. Manufacturers claim plasma displays have a contrast ratio of 3,000 to 1, while L.C.D. specifications are lower, around 800 to 1.

But numbers do not tell the entire story. In brightly lighted rooms, L.C.D. panels will appear to have much higher contrast; room light hitting a plasma set bounces off the screen's phosphors. As a result, its blacks will appear to be gray and muddied. Less light is reflected off an L.C.D. screen because of its polarizers and color filters.

The situation will be reversed when the lights are off. Without any ambient room light, the plasma set's picture contrast looks to be equal or better than the L.C.D.'s.

To create black in a plasma set, Mr. Weber points out, the gas discharge activity in the pixels is decreased. But in an L.C.D. set, black is created by blocking light. And liquid crystals have a difficult time blocking light at all angles.

Some believe there is little difference between L.C.D. and plasma sets once the lights are down. "In a dimly lit room, L.C.D. and plasma TV's perform equally well," Mr. Catapano of Consumer Reports said.

Color Reproduction

Plasma sets can display a wider range, or gamut, of colors, than L.C.D sets. But that gap will soon narrow. Sony recently announced the Qualia 005, an L.C.D. set that uses light-emitting diodes rather than a fluorescent backlight, raising the L.C.D. color gamut above that of plasma's.

But this new L.C.D. technology is still very expensive: when introduced in the spring, the 46-inch Qualia model will sell for $12,000. Samsung will introduce a 40-inch L.E.D.-based L.C.D. set for $9,000, a premium of $5,000 compared with its standard model. "But prices for this technology should come down pretty quickly," Mr. Sanduski said.

Brightness

Plasma creates a brighter pixel by increasing the charge applied to the gas. When very bright scenes are displayed, the electrical charge is lowered to prevent the display from overheating; but this also cuts overall brightness.

An L.C.D. screen, with its constant backlight, may be perceived by some people as producing livelier images.

"The L.C.D. image seems punchier than the plasma," Mr. Catapano said.

Burn-In and Panel Life

L.C.D. monitors are not subject to burn-in, or the tendency of static images to leave a ghostlike image on the screen. And while L.C.D. backlight bulbs can be replaced, when a plasma set's image decreases sufficiently, it is time to buy a new set.

Plasma's advocates say the burn-in problem is gone. And while early plasma displays lasted about 10,000 hours before the panel's brightness decreased by half, today's sets have a brightness half-life of about 60,000 hours.

Some manufacturers like Panasonic incorporate technology to reduce plasma burn-in by slightly shifting the image. And manufacturers caution users that the first 100 hours are especially critical to avoiding image burn-in.

Power Consumption

Plasma sets are said to use considerably more power than similarly sized L.C.D. models. But Mr. Weber argues that because L.C.D. panels have a constant backlight, while plasma uses power only when a pixel is lighted, power consumption is almost the same.

But not everyone agrees. When Consumer Reports tested power consumption, it found that a 30-inch L.C.D. consumed 133.5 watts, while a 42-inch plasma used 346.5 watts.

Some of the difference is attributable to the larger size of the plasma set, Mr. Catapano said. But not most of it. "A plasma TV has three power supplies for one set. That's pretty significant," he said.

When the Novelty Ends

So, who wins? Judging picture quality is not like keeping score at a ballgame.

Mr. Gudorf of Sony says brightness, contrast, color and viewing angle must be examined in concert. "If you focus on just one without examining the others, you won't be happy," he said.

Whether one buys a plasma or an L.C.D. set, the novelty of having either will eventually wear off. "At first, you're enamored with it, and after a while you see the imperfections," Mr. Catapano said.