Technology

GIZMOS: Flat-panel monitors: not all they're cracked up to be

May 2, 2005

I've discovered something really unexpected on my desk lately: a surface. After years of having monitors the size of packing crates looming over my desk, I now have two flatpanel monitors that actually take up less surface space together than one of the old CRT (cathode ray tube) monitors. The new LCD (liquid crystal display) flat panels are sleek, black, digital and much brighter than the old putty-colored CRTs that now seem so dreadfully old-fashioned. A flat-panel 19-inch monitor can be lifted with one hand. A CRT 19-inch monitor takes a strong man to lift onto a desk. I've seen work surfaces bowed down by them. I've also seen LCDs and CRTs side-by-side displaying the same images, and the LCD looks so much better that the CRTs would probably slink away in shame if they could.

Glare is almost nonexistent, which you can't say about CRTs. LCDs also can't "burn" the way CRTs can, leaving a ghostly image on the monitor that never goes away. So why am I disappointed with my fabulous flats?

LCDs are built very differently from CRTs. CRTs are not unlike run-of-the-mill color television sets of 30 years ago. They work by firing a stream of high energy at a thin coating of phosphor just inside the monitor's glass, which you see as a solid image because the beam travels too fast for the phosphor to fade before it comes back around for the next pass. If the same image is redrawn too many times on the same spot, the phosphors can become permanently damaged and you get monitor burn. That's why screen savers were invented.

LCDs don't work that way. LCDs turn a huge array of very small transistors on or off, and you see this as an image. And therein lies the first drawback to these little beasties. LCDs are famous for having dead pixels. A pixel is the smallest screen element a monitor can display. On a liquid crystal display, as the name implies, pixels are built of tiny crystals, switched by transistors. The little pixels can fail so that they're always on or always off. Those are dead pixels.

A well-known game console company recently enraged the gaming community by saying if a buyer found a dead pixel on a game unit, they should just live with it for a while and see if the dead pixels really detracted from their joy of ownership. It sounded unfeeling and arrogant, but the console manufacturer had a point. New LCDs often have one or more dead pixels. LCD technology is so demanding that many LCD screens have the odd weird pixel, but they're often difficult to see unless you have a totally dark or white screen.

A more difficult problem for flat panels in business offices is pricing, although that's quickly being rectified. CRT technology is now so old that stores almost have to give them away. A longtime maker of monitors offers a 17-inch LCD flat panel for about $470, and a 17-inch CRT for around $160. For the budget-conscious, losing desk space just can't compete with that kind of price difference. But LCDs use less power and they're supposed to last longer, so a case can be made that they're cheaper in the long run.

There are other drawbacks to the LCD. CRTs can be viewed adequately from almost any angle, but LCDs have only a limited arc within which they can be viewed. This measurement, called the "viewing angle," is measured in degrees. Swing many LCDs up or down and the image fades like a ghost. Two people sharing an LCD at uneven heights, such as one in a chair and the other looking over his or her shoulder, look like they're trying to peek over an invisible wall while under fire. Not every LCD is so persnickety; better ones give you almost 180 degrees from side to side, which is probably acceptable to most of us.

Resolution is another annoyance. You can change a CRT's resolution from, say, 1024-by-768 to 1600-by-1200, and it'll still look about equally sharp. But each LCD has its own "native" resolution, where everything looks good. Change the resolution, and the images "pixelate," or grow jagged around the edges.

Yet another problem is color rendition. Monitors have always been notorious for their capricious colors, but LCDs take this quirk to a new level. Graphics designers can be frustrated by the colors on printouts looking so much different than they did on screen.

My advice, as odd as it may seem, is that you hook up your own computer hardware to a prospective monitor and see how it works for you. If you have to, drag your own equipment into the store when you're looking at monitors. Monitors look different on different computers. If you have a laptop, it's even easier. People don't really do this, but there's no reason why they can't. It's just social conditioning that prevents it. If you're an office worker, you may spend more time with your new monitor than you do with your mate, so do some serious comparison shopping under some real-world conditions.



Altom is a systems interaction designer for Indiana University, based at IUPUI. His column appears every other week. He can be reached at tim@elementassoc.com.
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