Archive for Monday, July 23, 2007

Seeing the big picture

Differences between high-definition TVs have narrowed

July 23, 2007


They sit in their own section of the electronics store, their size and flickering images luring you over.

What makes these TVs tick?

Big-screen TVs come in three types:¢ LCD: Liquid crystal display screens get their picture from a layer of liquid crystal gel sandwiched between two polarized glass panels that show color when electrified. LCD uses much less power than other technologies with as good or better performance.¢ PLASMA: Plasma screens use hundreds of thousands of tiny gas-filled bubbles, or cells, which are held between two panels of glass. When electrified, they light up in combinations of red, green and blue to display a picture.Plasma TVs are susceptible to the burn-in effect, in which images displayed for long periods remain on the screen like a shadow.¢ PROJECTION: Rear-projection uses a light projector to beam LCD from behind the screen instead of in front, as with a movie theater. Rear projection is less expensive than LCD or plasma screens. The hot new technology in rear-projection televisions is the DLP, or digital light projection chip. This uses an array of miniscule mirrors to reflect light and make an even sharper picture.

The giant-screen TVs - plasma, LCD, projection - light up the showroom with pulse-pounding action scenes.

It's enough to make your living room's 27-incher seem utterly inadequate.

But if you do decide to supercharge your entertainment center (they call it a media wall now), the real deliberations begin.

The three competing big-screen technologies have become more similar. Gone are the days when LCD TVs could only be watched from head-on, or plasma TVs stayed small.

Rear-projection TVs, formerly hulking masses of plastic, have slimmed down enough to fit in almost any living room.

Jim Willcox, associate electronics editor of Consumer Reports magazine, said the distinctions between the three most common types of high-definition screens (LCD, plasma and rear-projection) have all but vanished. Picking one comes down to two main factors: budget and personal taste.

The first step is to determine what size screen to get. You may be tempted to go as big as your budget allows, but you also must be guided by the space in your viewing room. The best viewing angle comes when the screen, measured diagonally, is between one-third and one-fourth of the viewing distance, experts said.

For instance, if your couch is about 10 to 12 feet away from the TV, you might want a 36-inch screen.

Expect to spend between $1,000 and $3,500 on screens about 42 inches and larger, sizes that are becoming standard. Generally, projection TVs are the least expensive and plasma the most, in comparable-size screens.

Some shoppers will make their decision based on what a TV looks like when it's turned off, not the quality of the picture. For instance, a plasma screen may look sleeker to you.

"Aesthetics enter the equation," Willcox said.

There still are some differences in technology. LCDs generally get the edge in brightly lit rooms because the screen is far less reflective.

Plasma screens maintain better quality at larger screen sizes, though you need a screen of 42 inches or larger to notice. Rear-projection TVs may offer larger screens for smaller costs, but they're still bulkier than the plasma or LCD sets.

Screen resolution - a measure of how many lines the television can display at once - is another factor that's helpful in making comparisons. The higher the number, the sharper the picture. Most TVs being manufactured now display at 720 lines, but resolution can go up to 1080.

Keep an eye out for inputs on your new TV labeled HDMI, which stands for High-Definition Multimedia Interface. It will help you get the most out of your Blu-ray or HD DVD player, as well as video game consoles, which plug into them.


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