Comparison Of 15" LCD Monitors - Part I

Basics Of LCD

Essentially, three different liquid-crystal technologies are used in LCD monitors. We'll describe TN + film, IPS and MVA in the following pages. No matter which technology is used, all LCD displays obey the same fundamental principle.

One or more neon tubes make up the so-called backlight, which illuminates the display. The number of tubes may be limited to one for cheaper models, but you can find up to four in more expensive ones. Having two (or more) neon tubes doesn't really affect the picture quality in the least. Instead, the second tube acts as a backup in case the first one breaks. In effect, this considerably extends the monitor's working life, since a neon tube generally lasts a mere 50,000 hours, while the electronics will keep on plugging for 100,000 to 150,000 hours.

In order to ensure a uniform display, the light is redirected through a system of reflectors before it reaches the panel. Although it might not appear to be the case at first glance, the panel turns out to be incredibly complex. In fact, there are two panels, one on each side of the subpixels, each of which has been covered with a red, green or blue filter. In a 15" monitor, this adds up to 1,024 x 768 x 3 = 2,359,296 subpixels. Each RBG triad is controlled by a transistor that generates its own individual voltage. And this voltage, which can vary widely, causes the liquid crystals in each subpixel to move to a particular angle. The angle determines the quantity of light that passes through the subpixel, which, in turn, creates the image on the panel. The crystals' actual purpose is to deflect light so that it can pass a polarized filter before striking the display. If the crystals are arranged in the same direction as the filter, the light will pass through. On the other hand, if they are arranged perpendicular to the filter, the panel will remain black.