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structure-1559179_640At the time Nick Holonyak Jr. invented the first red light-emitting diode (LED), he knew he was on the precipice of a major breakthrough—one that would replace incandescent light bulbs in the future. In the more than 40 years since their invention, the humble LED has undergone more transformations than Holonyak might have imagined. Today, you probably have LED light bulbs in your [city] home.

To understand the journey the LED has taken to arrive at our households, below is a brief timeline of the history of LEDs.

1. 1907 – British scientist Henry Round discovers the phenomenon of electroluminescence, which refers to how certain materials generate light when charged by an electric current directly or through a powerful electric field. Although the light produced by initial experiments was very dim, it would pave the way for research many years later.

2. 1962 – Nick Holonyak, Jr., who was working for General Electric in the early 1960s, invents the first visible-spectrum light-emitting diode. His first creation consisted of red diodes, followed by green and yellow diodes. Holonyak’s invention would give him the distinction of being called the ‘Father of the LED.”

3. 1970s – Although subsequent improvements on red light-emitting diodes in the 70s would do little to improve their brightness, they nevertheless found widespread application as indicator lights in laboratory and military equipment.

4. 1972 – The invention of new colors would lead to new uses for LEDs. In 1972, Pulsar unveiled the world’s first LED watch called the Time Computer. With a hefty price tag of more than $2,000, the Time Computer was said to have been accurate to within 60 seconds every year. It was also the first small device of its kind to use LED technology and electronic components to determine the time. The Time Computer, however, required wearers to press a button to see the time, as leaving it on continuously drained the batteries very quickly.

5. 1990s – Blue light-emitting diodes were common in the 1990s, which in turn led to the invention of white LEDs. These were created by scientists applied a coating of phosphor on the blue diodes to give create a diffused white light. The technology was improved further by combining red, green, and blue diodes to create a white glow. This leap in innovation allowed for LEDs to be used in a wide variety of applications, from traffic lights, television sets, and flashlights among others.

6. 2000 – The U.S. Department of Energy (DoE) pushes white LED lighting to spur their adoption as home lighting solutions.

7. 2008 – The DoE announces the L Prize competition, which was designed to encourage the development of super-efficient solid-state lighting solutions and replace inefficient incandescent bulbs.

8. 2009 – Philips submits its entry into the competition, a 60-watt incandescent equivalent that consumed just 10 watts of electricity.

For more than 20 years, LED lights bulbs have slowly but surely encroached upon the territory once occupied by inefficient incandescent light bulbs. Only time will tell what further improvements will be made with LED technology. If the emergence of smart LEDs is any indicator, we could be seeing LEDs with more features besides just generating light in the near future.

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