Technology

Time to Ditch That CRT


There are plenty of reasons to upgrade your computer monitor to an LCD model, but radiation from a cathode-ray-tube screen isn't one of them

Reader Wayne Powell wants help deciding whether to upgrade an employee's computer monitor. "I have an employee who spends a lot of time—probably six-plus hours a day, on average—in front of a 22-in. NEC (NEC) cathode-ray-tube (CRT) screen doing graphical work. He has used this monitor for six years and now wants to switch to a 24-in. liquid-crystal display (LCD), citing the radiation risk from the CRT.

"Since LCD screens are so much bigger, better, and less costly than they were just a year or two ago, changing is not a big deal. But I wonder if he has been facing (literally) a higher risk of harmful radiation. It reminds me of the ongoing debate about cell-phone radiation. What are your thoughts?"

There may be many reasons to ditch that old CRT, but radiation really isn't one of them. The situation is quite different from cell phones. I haven't seen any studies that have convinced me cell phones pose a radiation hazard. But at least cell phones, of necessity, radiate microwaves that do have health effects—at least, at higher doses than cell phones emit.

CRTs Made Safer

CRTs generate a picture by firing high-energy electrons at the phosphors on the inside of the screen. In the process, some electromagnetic radiation and, in some cases, a tiny quantity of X-rays are given off. In the early 1990s, a couple of studies suggested health hazards from CRTs—in particular, excessive rates of miscarriage among pregnant users. But subsequent large-scale epidemiological studies failed to confirm the findings. Nonetheless, there was a move to limit this radiation. Swedish standards, known as TCO93 and TCO95, were generally adopted by CRT manufacturers, and levels of radiation, already low, fell considerably.

LCDs use an entirely different technology. Each pixel consists of a tiny liquid-crystal shutter toggled by a transistor between opaque and transparent states. When turned on, a pixel lets light shine through a red, green, or blue filter. The only radiation generated by this system is visible light, without which a display wouldn't be of much use.

That NEC monitor is six years old, meaning it has lost a significant amount of its original brightness. It's big and clunky. Worse, it draws a lot more wattage than an LCD. A big, 24-in. LCD might even make him more productive. So yes, it may well be time to get your employee a new display. But no, not for fear of radiation from the old one.

Wildstrom is Technology You columnist for BusinessWeek. You can contact him at techandyou@businessweek.com or follow his posts on Twitter @swildstrom.

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