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If you were born before the 21st century, then you may have noticed a drastic change in the way we illuminate our world.
The warm amber glow of street lamps are now bright white and the hum and flutter of office lights are going quiet and steady.
LEDs are low energy, efficient, and environmentally friendly light source and they are rightfully taking the place of old fashioned bulbs and tubes. Their rise began just 28 years after Thomas Edison first patented the incandescent bulb.
LEDs or Light-Emitting Diodes produce light when electricity is applied to negatively charged semiconductors. This causes electrons to rapidly combine and form light particles. Learn more about how LEDs work here.
LEDs consist of a small chemical chip that is encased in a plastic capsule.
They are so efficient and well-designed that they can last as long as 50,000 hours.
The Discovery of LEDs
Captain Henry Joseph Round first discovered the potential for LEDs. In 1907, while experimenting on ways to improve the amplification of radio signals, he added tension and ran electrical currents through semiconductors.
He saw that certain substances emitted light when a current passed through them. He noted how when 10 volts was applied to a silicon carbide crystal, it produced a yellowish light.
His observations were then published in the magazine Electrical World and are the first known descriptions of electroluminescence.
The Next Phase
It wasn’t until 1927 that Oleg Vladimirovich Losev would actually publish a purposeful investigation into the phenomena. He observed the same effects as Round but then took it a step further. He built a crystal diode out of zinc oxide and silicon carbide.
After running an electric current through it, he noted the emission of photons and a patented what he called the “Light Relay”.
coHe published his results in Russian, German, and British papers and saw its immediate potential in telecommunications.
Losev died before he could take his findings further. However, small progress was made various people discovered that certain diodes emitted infrared light whenever they were connected to electrical currents.
When Were LEDs Invented?
LEDs were invented in 1962 by Nick Holonyak Jr. He first developed a diode for General Electric that emitted red light in the visible spectrum.
A year later he went on record as saying that LEDs would soon replace incandescent bulbs. A graduate student of Holonyak invented a yellow LED and an even brighter red LED in 1972. In 1979, Shuji Nakamura created a blue LED.
LEDs remained expensive at $200 dollars a piece until Fairchild Semiconductors reduced the cost to 5 cents using innovative and ingenious methods of production and packaging.
LEDs and The Current Situation
LEDs are now commonplace and have begun to replace incandescent, fluorescent and neon light at a rate that surprised even Holonyak Jr.
Though they are still expensive at a cost per lumen and are highly sensitive to the outside temperature, LED lighting is fast becoming our best option for illumination with many different types of LEDs now in production.
Their efficiency, versatility, and lack of dangerous chemicals like mercury makes LEDs extremely safe and will only become more essential in a world looking to battle climate change and waste. Electric light has come a long way since burning filaments and glowing crystals.