What is a LED DISPLAY?

A light-emitting diode (LED) is a semiconductor device that emits incoherent narrow-spectrum light when electrically biased in the forward direction of the p-n junction. This effect is a form of electroluminescence. An LED is a small extended source with extra optics added to the chip that makes an LED to emit a complex radiation pattern. The color of the emitted light depends on the composition and condition of the semiconducting material used, and can be infrared, visible or near-ultraviolet.

Henry Round, of Marconi Labs first noted that semiconductor diodes could produce light in the late 19th century. Russian Oleg Vladimirovich Losev independently created the first LED in the mid 1920s; his research, though distributed in Russian, German and British scientific journals, was ignored. Rubin Braunstein of the Radio Corporation of America reported on infrared emission from gallium arsenide (GaAs) and other semiconductor alloys in 1955. Experimenters at Texas Instruments, Bob Biard and Gary Pittman, found in 1961 that gallium arsenide gave off infrared (invisible) light when electric current was applied. Biard and Pittman were able to establish the priority of their work and received the patent for the infrared light-emitting diode. Nick Holonyak Jr. of the General Electric Company developed the first practical visible-spectrum LED in 1962. Holonyak's former graduate student, Dr. M. George Craford, invented in 1972 the first yellow LED and 10x brighter red and red-orange LEDs. Dr. Shuji Nakamura of Nichia of Japan is the inventor of the white LED which took a composite YAG phosphor coating on top of a blue LED and converted it to white light. Dr. Nakamura was awarded the 2006 Millennium Technology Prize for his invention.

[ From Wikipedia.org ]