March 14, 2005

Q: How long can I expect an LCD or plasma display to last?

Jim

A: The trouble with new technologies is that no one knows how well they’ll work over the long term. In theory, an LCD panel should last indefinitely because, unlike a plasma display, it has no phosphors that can wear out. Nothing lasts forever, of course, but the conventional thinking is that the LCD and DLP technologies have the edge when it comes to longevity.

Plasma shares with the conventional cathode-ray tube (CRT) the use of phosphors that glow when hit by a stream of electrons. In a CRT, these electrons are shot from a gun at the back of the picture tube and hit the screen, which contains the phosphors; in a plasma panel, each pixel has its own phosphors and source of electrons. In both cases, however, the phosphors become less sensitive over time. This is most noticeable as visible burn-in in areas of the screen with uneven illumination, such as the black bars above and below a letterboxed image. Eventually, plasma displays fail entirely.

One plasma maker claims that his products will last some 20 years, although whether or not there is any proof of that is anyone’s guess. A good CRT can be counted on to last for a decade on average, which would seem a reasonable guess for plasmas as well. (Many CRTs are still going strong long after ten years, of course.)

Some years ago, a major television manufacturer told me that his company expects that the average buyer will upgrade his or her television set after about seven years. With even the most conservative estimates of display life, it seems likely that you’ll want to replace your television long before it dies.

…Ian G. Masters