Plasma, LCD, and DLP

The flattest of the flat HDTVs are the Plasma and LCD sets. They are as thin as a few inches, and are easy to hang on your wall. DLP sets are thicker, but still slim enough to be worth considering as an alternative to Plasma or LCD.

Plasma
Plasma sets get their name from the way the picture is created: a wire grid is mounted between two glass panels, and the space in between is also filled with a gas. When points on the grid are excited by an electrical signal, the gas in that area glows in a plasma state, creating a picture element.

Plasma is generally considered to have the highest quality picture, especially in the middle and larger sizes. It also tends to look better than other types when viewed at a wide angle, with very little darkening or color shift. LCD sets often have a higher resolution then Plasmas of the same size, but the difference is nearly impossible to see.

There are a few things to consider, though. Picture quality varies considerably in different Plasma sets, so it's important to read plenty of reviews before choosing one particular model. And the glass screen can create a glare problem, so it's important to have a relatively dark area for the TV. And, people who live at high altitudes might experience problems with the set overheating due to the thin air.

A common complaint of Plasma users is a phenomenon called "burn-in": areas of the set that display a constant image can retain that image when the picture changes or the set is turned off. This is why screen savers were invented for computers, since early computer monitors had the same problem. With a high quality set and proper care, however, burn-in will not be a problem.

LCD
LCD stands for Liquid Crystal Display, the same technology used in most flat computer monitors. LCD technology is improving fast, and many of the higher-end LCD TVs have just as good a picture as a Plasma. Since LCD displays often have a higher resolution than Plasmas of similar size, they work well doubling as computer monitors. The plastic screen of an LCD reflects very little light, giving it an advantage over Plasma for viewing in a room with normal light or open windows.

One slight weakness of LCD compared to Plasma is the viewing angle. When you move beyond a certain angle from straight-on (usually 65 or 70 degrees) the screen darkens and the colors shift noticeably. On the other hand, when you get to the angle at which this is a problem the picture is hardly watchable anyway, because you're mostly looking at the side of the TV.

As the technology of both Plasma and LCD continues to improve, the disadvantages of each get smaller. More and more, the differences in style are less important than the price and quality differences between individual sets.

DLP
DLP sets are sort of the odd one out, as they are not quite as flat or light as the others. But, they are still much flatter than a traditional TV and are worth considering if you're considering a Plasma or LCD set.

DLP stands for Digital Light Processing. It is a rear-projection technology where the signal is broken up into light pulses, then reflected from an oscillating mirror to illuminate the screen from behind, creating the picture.

The big advantage of DLP sets are their reasonable prices in the larger sizes. A 60 inch DLP HDTV can be found for $2000 to $3000, while a Plasma in a similar size and quality would exceed $4000, and a similar LCD HDTV, if you could even find one, would cost over $6000. DLP sets also have very good black levels and typically excellent image quality, making them great for watching movies, and they still look great even when you are sitting very close to the screen.

The only real disadvantage of DLP sets compared to Plasma and LCD is their thicker profile. They are not appropriate for hanging on the wall. Some DLP viewers have complained of the rainbow effect but this problem has almost completely vanished by now.