An LED (acronym for Light Emitting Diode) is a light emitting diode, that is to say, an electronic component of two terminals that allows current to electricity through it without the intermediary of a gas, unlike traditional bulbs.
The LEDs are present in our daily lives. We can find them in mobile screens, tablets, computers and televisions, surgical, microscopic equipment, airstrips, roads, all kinds of signs, signage, automotive, decoration, radars and military equipment, information panels and printers, among others. Let’s see who we have to thank for their discovery.
Henry Joseph Round (1881-1966), an expert in radio and personal assistant of Marconi, was the first to observe the light emitted by a diode silicon carbide, in 1907. He made an experiment with germanium crystals that allowed him to discover the physical effect of electroluminescence and to create the first semiconductor diode. However, it was forgotten because of its high cost and not see a long future.
Although Oleg Vladimírovich Lósev (1903-1942), a Russian scientist and inventor, developed the first LED in 1927, the invention is attributed to Nick Holonyak, in 1962, when he worked as a scientific advisor on a General Electric laboratory, in Syracuse (New York). That first red LED, based on semiconductors, emitted photons in the infrared spectrum (invisible to the human eye).
In 1971, Jacques Pankove developed blue LED low-power technology. But it was not until 1993 when it appeared the first fully LED blue and refined, thanks to Shuji Nakamura de Nichia, a milestone that marked the beginning of LED lighting, and the beginning of the relegation of the traditional to the background.
The first yellow LED was invented in 1972 by M. George Craford, a former graduate student Holonyak. Craford, who was part of the Monsanto company, improved brightness of red and red-orange LEDs, using gallium arsenide phosphide and, thus it was ten times brighter than Holonyak’s ones.
In 1976, T. P. Pearsall developed the first high efficiency and brightness LED for fiber optic telecommunications by inventing new semiconductor materials specifically adapted to the wavelengths of optical fiber transmission.
In 1995, Alberto Barbieri investigated the reliability and efficiency of high-brightness LED and showed a “clear contact” LED at the Laboratory of the University of Cardiff. The existence of high-efficiency blue LED soon lead to the development of white LED, as blue was not bright enough. Thus, in 1998, Lumileds company sold the first white power LED, by adding phosphorus to blue.
Later, in 2001 and 2002, processes for gallium nitride LEDs on silicon were presented effectively. In January 2012, Osram was able to present the high-power indium gallium nitride on silicon substrates commercially.
Do you have any devices that incorporate LED technology? Tell us about them, please.