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1927
First LED
Oleg Vladimirovich Losev (1903–1942)
“Although the electroluminescent property of some crystals was discovered in England in 1907, it took more than a decade of work by the self-taught Russian scientist Oleg Vladimirovich Losev to develop a theory (based on Einstein’s photoelectric theory) of how the effect worked, and to produce devices that could be used in practical applications. In total, Losev published 16 academic papers that appeared in Russian, British, and German scientific journals between 1924 and 1930, comprehensively describing the devices in the process. He went on to come up with novel applications for light-emitting diodes (LEDs and other semiconductors, including a “light relay device,” a radio receiver, and a solid-state amplifier, before dying of starvation during the Siege of Leningrad in 1942.
LEDs were rediscovered in 1962 by four different groups of American researchers. This time the technology would not be lost. Compared with incandescent, fluorescent, and nixie tubes of the day, LEDs consumed far less power and produced practically no heat. They had just three disadvantages: they could make only red light, they were not very bright, and they were fantastically expensive—more than $200 each at the beginning.
By 1968, improvements in production let companies push the price of LEDs down to five cents each. At that price, LEDs started showing up in calculators, wristwatches, laboratory equipment, and, of course, computers. Indeed, LEDs arranged as individual lights and seven-segment numeric displays were one of the primary outputs for the first generation of microcomputers in the mid-1970s. Even the early LEDs could be switched on and off millions of times a second, resulting in their use in fiber-optic communications. In 1980, infrared LEDs started showing up in television remotes.
Although blue and ultraviolet LEDs were invented in the 1970s, a number of breakthroughs were required to make them bright enough for practical use. Today those challenges have been overcome. Indeed, the bright-white LED house lights that have largely replaced both incandescent and fluorescent light bulbs are based on an ultraviolet LED that stimulates a white phosphor.”
SEE ALSO First Liquid-Crystal Display (1965)
“Eight decades after it was invented in 1927, light-emitting diodes were finally bright enough and cheap enough to replace incandescent light bulbs on a massive scale.”