A Cathode Ray Tube (CRT) is a monitor similar to a traditional TV set.
It contains millions of tiny red, green and blue phosphor dots that glow when they are
struck by an electron beam travelling across the screen, and thus create a visible image.
CRTs are cheap, but they are heavy, can flicker and emit radiation.
A Liquid Crystal Display (LCD) is made of two glass plates with a liquid crystal
material between them. The crystals block the light in different quantities to create the
image. Active –matrix LCDs use TFT (thin film transistor) technology, in which each pixel
has its own transistor switch. They offer better quality with less flicker and take up less
space. The disadvantage is that the screens can be viewed only from a limited angle.
A plasma screen - images are created by a plasma discharge which contains noble gases.
Plasma screens allow larger screens and wide viewing angles.
Organic Light-Emitting Diodes (OLEDs) – are thin-film LED displays that do not require
a backlight to function. The material emits light when it is stimulated by an electrical current, which
is known as electroluminescence. They consume less energy, produce brighter colours and are flexible – can
be bent or rolled up when they are not being used
