Liquid crystal display technology works by blocking light. Specifically, an LCD is made of two pieces of polarized glass (also called substrate) that contain a liquid crystal material between them. A backlight creates light that passes through the first substrate. At the same time, electrical currents cause the liquid crystal molecules to align to allow varying levels of light to pass through to the second substrate and create the colors and images that you see.
Active and Passive Matrix Displays
Most LCD displays use active matrix technology. A thin film transistor (TFT) arranges tiny transistors and capacitors in a matrix on the glass of the display. To address a particular pixel, the proper row is switched on, and then a charge is sent down the correct column. Since all of the other rows that the column intersects are turned off, only the capacitor at the designated pixel receives a charge. The capacitor is able to hold the charge until the next refresh cycle.
The other type of LCD technology is passive matrix. This type of LCD display uses a grid of conductive metal to charge each pixel. Although they are less expensive to produce, passive matrix office monitors are rarely used today due to the technology's slow response time and imprecise voltage control compared to active matrix technology.
LCD displays offer super sharp pictures and great color. But do the pros outweigh the cons when it comes to LCD TV displays? Before deciding on a thumbs up or thumbs down, you should understand how an LCD display works.
Mechanics of an LCD display
The LCD consists of a large number of pixels, or picture elements, consisting of liquid crystal molecules held between two sets of transparent electrodes.
The liquid crystals react in predictable ways when the electrical charge running between those electrodes is changed — meaning they twist and move in ways that let different amounts (and colors) of light through the crystals. The LCD has a control system that translates your video signals into the proper charges for each electrode. A light source shines through the LCD panel and creates your picture.
When compared to the other type of flat-panel display (plasma), LCDs tend to be found on the smaller size of the spectrum. You’ll rarely find a plasma smart TV smaller than 42 inches, but you can find LCDs at sizes as small as 13 inches.