In it an electric current is passed through a semi crystalline liquid, in which the crystals align themselves with the current. Further by combining transistors with these liquid crystals, patterns could be formed which can represent numbers or letters. LCDs displays are used in laptops and desktops and for desktops LCDs are available in either analog or digital interfaces but depend on video support on PC. Two types of LCD displays are used which differ in quality of the image.
Active Matrix – In it a transistor is behind each pixel, when switched on, activates the pixel. It is very crisp and easy to look at but requires more power to operate and consumes more battery power. Active matrix uses thin film transistors (TFT) which are tiny switching transistors and capacitors and are arranged in a matrix on a glass substrate.
Passive Matrix – It has two rows of transistors: at the top and at the side. To turn on a particular pixel a signal is sent to the x- and y-coordinate transistors for that pixel, thus turning them on.
The main difference between active matrix and passive matrix is image quality. PC takes more time to light the pixel hence, the response of the screen to rapid changes is poor.