History of LEDs
In 1907, British scientist Henry J. Round dicovered the physical effect of electroluminescence, an optical and electrical phenomenon in which a material emits light in response to an electric current passed through it or to a strong electric field. The light produced was very dim and not bright enough to stimulate further research.
In 1962 the first visible spectrum LED light was produced by Nick Holonyak Jr. and was red in colour. This coined his nickname, 'Father of the Light Emitting Diode'. The red LED's were not bright enough to be seen in daylight so the first LED applications were mainly used as indicator lights for military use.
M. George Craford, a student of Holonyak, invented the first yellow LED in 1972 and then went on to produce a much brighter red LED.
As technology progressed in the 1970's additional colors were created and as new colors became available, new uses for LED lights were in demand. LED's were used in applications such as calculators, digital watches and test devices.
The first superbright LED's were developed in the 1980's and were brighter, more stable and cost efficent which saw the demand for LED's rise dramatically.
From 1990 the use of LED's became standard in various industrial applications from switch cabinets to measuring instruments, in consumer products such as Hi-Fi equipment, telephones or personal computers and in traffic signal installations for road and railway or in indoor and outdoor automotive lighting.
For two decades LED lights have been replacing incandescent globes in homes and businesses, offering a cheaper, more efficient service in a wide variety of contexts.
