• LCD stands for liquid crystal display. LCD panels are made of two layers of transparent material which are polarized and are glued together.
• One of the layers is coated with a special polymer that holds the individual liquid crystals. Current is then passed through individual crystals which allow the crystals to pass or block light to create images.
• LCD crystals do not produce their own light, so an external light source, such as florescent (CCFL/HCFL) or LEDs are needed for the image created by the LCD to become visible to the viewer.

• Currently almost all LCD TVs use LED light sources instead of a fluorescent light source. Unlike standard CRT and Plasma TV, since there are no phosphors that light up, less power is needed for operation and the light source in an LCD TV generates less heat than a Plasma or CRT TV.
• Also, because of the nature of LCD technology, there is no radiation emitted from the screen itself.

Passive-matrix:

• LCDs use a simple grid to supply the charge to a particular pixel on the display. Creating the grid is quite a process.

• It starts with two glass layers called substrates. One substrate is given columns and the other is given rows made from a transparent conductive material. This is usually indium-tin oxide.

• The liquid crystal material is sandwiched between the two glass substrates, and a polarizing film is added to the outer side of each substrate.

• To turn on a pixel, the integrated circuit sends a charge down the correct column of one substrate and a ground activated on the correct row of the other.

Active-matrix:

• LCDs depend on thin film transistors (TFT). Basically, TFTs are tiny switching transistors and capacitors. They are arranged in a matrix on a glass substrate.
• 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.