The Light Emitting Diode

A light emitting diode is a semiconductor so that the flow of electicity is controlled as in the normal PN junction manner.

However, in this case, the current is allowed to flow through various kinds of chemical based semiconductor material which then light up to high brightness when exposed to a current.





Its only been in the lasdt 3-4 years that economies of scale have now occurred with the chemical elements so these devices are available to consumers in the form of lightbulbs or video displays.

Different kinds of chemical material give rise to difference colors and these different materials are all mixed together to make individual color LED pixels which can be made relatively small.





LED pixel sizes are on order of 2 - 6 mm in size - which now allows for reasonably large LED displays to be made with high pixel densities as shown below for an 88-inch monitor with 8 million pixels in it (2K x 4K)



An LED screen is actually an LCD screen, but instead of having a normal CCFL backlight, it uses light-emitting diodes (LEDs) as a source of light behind the screen. An LED is more energy efficient and a lot smaller than a CCFL, enabling a thinner and more lightweight television screen. As a result LED screen will now likely replace all LCD screens.