X-bit labs

X-bit’s Guide: Contemporary LCD Monitor Parameters and Characteristics (page 18)

Category: Other

by Oleg Artamonov

[ 10/26/2004 | 02:58 PM ]

The second thing with respect to safety of the monitor, besides radiations is as follows: old monitors could be uncomfortable – not really dangerous – due to a powerful electrostatic field at the front side of the tube, but all monitors of the MPR-II standard (not mentioning the series of TCO standards) have a conductive grounded coating on the tube, which reduces the electrostatic field to acceptable values.

Thirdly, the deflecting system of the CRT monitor produces rather a powerful electromagnetic field. This system, however, is located at the root of the tube, i.e. rather far from the user. Moreover, it is covered with a protective metallic screen in good modern monitors – in other words, you can only hurt yourself by sitting all days long with your head resting on the rear or side panels of the monitor. Nothing is going to happen to you if you’re sitting in front of the screen, as normal people do.

Thus, it seems like the modern CRT monitor has nothing to hurt your health with. All the ascribed radiations are either non-existent or dumped to the safe level. By the way, the users usually complain of headaches, eye strains, and worsening eyesight. But I guess if a person received such a dose of radiation as to feel a headache or eye-strain, he’d better think about making its will, rather than about replacing the monitor.

So, the discomfort from the monitor is due to the bad quality of the image rather than to any radiation. The most common problems are bad focusing, bad convergence, or a graphics card that’s outputting a “fuzzy” image on the screen. It is the insufficiently sharp onscreen picture that makes your eyes sore. Sometimes, the monitor is just set up incorrectly: the contrast is at the maximum, while the brightness control is at zero, or vice versa (the brightness is too high, while the contrast is low). Working in full darkness is a strain for your eyes, too…

That said, the main advantage of LCD monitors is not the lack of radiations (there are no electron beams or deflection systems or high voltages at all, save for the power voltage of the backlight lamps), but rather the lack of such notions as “convergence” or “focusing” in the LCD world – LCD monitors are always outputting an ideally sharp image, save for some inexpensive models that have problems with setting up for the analog signal from the graphics card. This, however, cannot eliminate the problem of setting up the brightness and contrast correctly: excess brightness or insufficient contrast of an LCD monitor will hurt your eyes much like those of a CRT monitor do.

This is the end of the theoretical part of this article. Let’s now go over to practice – to the various types of LCD matrices available in the market and their typical characteristics.