In 1970, Fergason made the first operating LCD. Prior to this invention, LCD used a large amount of power, provided a limited life, and had poor visual contrast. In 1971, the first LCD were demonstrated publicly and enthusiastically accepted. LCD stands for Liquid Crystal Display are organic substances that reflect light when voltage is applied. The liquid crystal display consists of a liquid suspension between two glass or plastic panels. Crystals in this suspension are naturally aligned parallel with one another, allowing light to pass through the panel. When electric current is applied, the crystals change orientation and block light instead of allowing it pass through, turning the crystal region dark. LCD monitors are typically found in laptop computers, or inside multimedia projectors. Most flat-panel desktop computer monitors are based on LCD technology.

However, early version of liquid crystals were unstable and unsuitable for mass production. Only when a British scientist discovered "Biphenyl", a stable liquid crystal material, that made it possible for LCD technology to take off. The first generation LCD appeared on calculators, then game sets and watches.

How an LCD works?

The cross-section of the TFT LCD panel looks like a multi-layer sandwich. At the outermost layer on either side are clear glass substrates. Between the substrates are the thin film transistor, colour filter panel that provides you the necessary red, blue and green primary colours, and the liquid crystal layer. Completing the LCD is a fluorescent backlight that illuminates the screen from beneath.

Under normal conditions when there is no electrical charge, the liquid crystals are in an amorphous state. In this state, the liquid crystal pass through. By subjecting the liquid crystal layer to varying amount of electrical charges, the liquid crystal layer will allow different amount of light to pass through, as they orientate themselves according to the control center for the liquid crystals.

Just like in an ordinary CRT, the red, green and blue liquid crystal "chambers"; make up one pixel (picture element). By subjecting the red, green, blue chambers to varying degrees of electrical charges, different colours can be achieved.

An entire TFT screen is made up of a grid of pixel, with each pixel having a transistor turning it on or off. This is where you get your resolution. Thus, for an LCD to provide a screen resolution 1024 x 768 pixel (SVGA), it must have that number of pixels.