History of LED

1907

Henry Joseph Round first observed the phenomenon of electroluminescence in a piece of Silicon Carbide (SiC)

1920

Bernhard Gudden and Robert Wichard Pohl carried out further experiments using phosphor material made from Zinc Sulphide doped with Copper.

1936

George Destriau published a report on the emission of light by Zinc Sulphide (ZnS) powders, following the application of an electric current and widely credited with having invented the term “electroluminescence”.

1950's

British experiments into electroluminescence using semiconductor Gallium Arsenide led to the first “modern” Light Emitting Diode LED.

1960's

The visible (red) light LEDs were produced using Gallium Arsenside Phosphide.

1970

By the mid 1970’s Gallium Phosphide was itself being used as the light emitter and was soon producing a pale green light.

1980's

The use of Gallium Aluminium Arsenide Phosphide LEDs brought the first generation of superbright LEds, first red, then yellow and finally green.

1990's

The first significant blue LEDs also appeared using Silicon Carbide.

2000's

The ultra bright blue chips became the basis of the white LEDs in which the light emitting chip is coated with fluorescent phosphors. These phosphors absorb the blue light from the chip and then re-emit it as white light.