Plasma vs. LCD

What's the difference between plasma and LCD?

Both plasma and LCD flat-panel displays are capable of delivering high-definition TV within a thin case, but there are differences between the two.

LCD TVs are available in many more screen sizes than plasma. Plasma screens start as small as 32 inches, but the majority of sets have 42-inch or 50-inch screens. Some giant plasma TVs up to 150 inches have been demonstrated. In contrast, LCD TVs can be as small as a few inches, and manufacturers have demonstrated LCD TVs with screen sizes of up to 108 inches. For home theaters, LCD TVs with screen sizes from 32 inches to 52 inches are most popular.

LCD TVs as small as 32 inches are now capable of displaying HDTV in its highest broadcast resolution of 1920 x 1080i (most HD televisions shows are broadcast at this resolution). In addition, most can accept and display 1920 x 1080p (progressive) signals, such as those from a Blu-ray player or game console. Budget-priced LCD displays, as well as smaller-screen models, are only able to display the lower HD resolution of 720p. These TVs are also capable of accepting signals in all HD resolutions, including 1080i and 1080p, scaling images as needed to fit their screens.

In the past, most plasma TVs were capable of only displaying the lower HD resolution of 720p. However, full 1920 x 1080 plasma TVs are now the norm as well, and prices have dropped to the point where they are competitive with their LCD counterparts. (You can read more about high-definition resolution in our report on HDTV.)

Plasma TVs are known for their ability to display dark colors and deep blacks better than LCD TVs. That makes plasma TVs a good choice for movie watching, where dark scenes are common. LCD TVs appear brighter, but they don't display dark scenes as well. If your room is brightly lit, an LCD might be a better choice, since the screen won't wash out in daylight. Many LCD screens have an adjustable backlight, so you can control the brightness of the screen. Plasma TVs, on the other hand, are more prone to glare when viewed in a bright room. Some newer plasma TVs have screens that do a better job of handling reflections, while some current LCD TVs use a panel that's more reflective than others.

Plasma screens have wider viewing angles than LCD flat screens. That means you can sit at more of an angle and still get the best picture, one reason why reviewers (such as CNet.com's David Katzmaier) say a plasma screen gives you "better home theater performance than LCD." With conventional TVs, the picture stays the same from virtually any angle. With LCD televisions, sitting too far to one side will result in a loss of brightness. It's the same effect you get if you try to look at a laptop screen from a sharp angle. Reports say that better LCD TVs have fewer issues with limited viewing angles.

LCD TVs can sometimes have problems with moving images. Those problems show up in two ways. The first is ghost or "comet" trails following fast-moving objects in a scene. Reviews say that ghost trails are almost nonexistent in better performing LCD TVs.

The other problem is image blur -- pictures look softer or appear to smear -- with fast action. The newest LCD TVs are using faster 120Hz refresh rates -- the rate at which individual images are placed on the screen -- instead of the more traditional 60Hz in an attempt to overcome that. However, the signal processing involved is fairly complex because the source material has its own frame rate (the number of individual images per second), typically 24 or 60 depending on whether it is film or video, and reports say that some LCD TVs do a better job in this regard than others. Robert Silva at About.com has a great primer explaining refresh rates and frame rates. See our Useful Links page for details.

Although larger LCDs are now available, if you want a screen over 47 inches (measured diagonally) plasma is generally a little less expensive. LCD is the clear choice if you want a smaller screen size. Because LCDs are available in a wider range of sizes, you can choose a size to fit your room and budget. If you want to put your TV in a brightly lit room, LCD is the way to go, but plasma will generally look better in light-controlled environments.