These days, LED lighting can be found just about everywhere. The light-emitting diode (LED) is currently the most energy-efficient lighting technology available. It is one of the most rapidly developing technologies around and it is used in a wide variety of applications. You can find it used in homes, businesses, automobiles, agricultural equipment, and more. But did you know that its history of development stretches back over a hundred years? Before we go back to LED lighting’s past, let’s understand how it currently functions.
How does it work?
LED lighting is a type of solid-state lighting (SSL) in which a semiconductor transforms electricity to light in a small space (the diode) of about one square millimeter or less. LEDs create light by electroluminescence in a semiconductor material. Electroluminescence is the phenomenon of a material emitting light when an electric current or an electric field is passed through it.
Instead of a filament, each LED lamp or fixture contains multiple light-emitting diodes. The light that it generates projects in one direction as opposed to 360 degrees from the source. This eliminates the need to use reflectors that are typically used with other sources of light such as fluorescent and halogen.
The story of the invention of the LED dates to some of the earliest days of wireless technology. Very little was understood about semiconductors at the time. Even less was understood about using them to emit light. LEDs have been commercially available since the 1960s, but the birth of the LED stretches many years before this. The invention of LEDs has its roots in much earlier developments that weren’t even related to lighting technology. Let’s take a journey back in time to explore the history of LED lights and the history of LED light bulbs.
The Complete Timeline of LED Lighting History
In 1907, electroluminescence was discovered by Henry Joseph Round who was a British radio engineer.
Early radio detectors were typically created utilizing crystals of what would later be called semiconductors. A thin wire would be placed onto the detector’s surface and then a point-contact diode would be made. These were called “Cat’s Whiskers”. Round observed that when an electrical current was passed through some of the detectors, one of them emitted light. However, the light was too faint to be of much use for anything.
In 1921, Oleg Losev, who was a Russian physicist, observed Round’s discovery regarding electrical currents and inorganic material and called it the “Round Effect”. In 1927, Losev published a report that contained theories on his findings from continued studies of electroluminescence and light-emitting diodes in radio sets.
Losev continued his studies of what would later become known as semiconductor technology until 1942. In 1942, he would be killed in the Siege of Leningrad during World War Two. Because of this, the records of his work were mostly destroyed and they would not reemerge until the 1950s.
In 1936, a French physicist named Georges Destriau would first use the word “electroluminescence”. This came from a paper that he published about the occurrence of light being generated by Zinc Sulphide powder from the conduction of an electric current through it.
In 1951, the development of the transistor leads to a big step forward in semiconductor physics. This made it possible to better explain the process of light emission. Because of this, new diodes were invented and developed.
In 1958, the first green LED was created at RCA Laboratories by Rubin Braunstein and Egon Loebner.
In 1962, the red LED was developed by Nick Holonyak at General Electric Laboratories. It is the first of its kind on the visible wavelength.
In 1964, IBM began to use LEDs for the first time on circuit boards in early computers. They were used as indicators on equipment. This was also around the time that LEDs began to be manufactured. One of the first companies to do this was Monsanto which was a supplier of raw semiconductor materials.
In 1968, Hewlett Packard began to incorporate LEDs into its calculators.
In 1971 and 1972, blue, orange, yellow, violet, and green LEDs were developed using new semiconductor materials. Also at this time, LEDs are invented that are much brighter than earlier versions. Monsanto begins to manufacture LED lights on a large scale.
In 1976, high brightness LEDs that can be used for fiber optic applications were developed by Thomas P. Pearsall. This would improve communications technology on a global scale.
In 1986, Walden C. Rhines and Herbert Maruska created a blue LED using Magnesium at Stafford University. The development would establish future standards for LED lighting. It would set the stage for high-brightness LEDs that could be used in other applications besides indicator lights.
From 1992-1995, Shuji Nakamura along with two other colleagues (Isamu Akasaki and Hiroshi Amano), using Gallium Nitride, invented ultra-bright blue LEDs. Just afterward, using Indium Gallium Nitride, he developed high-intensity green and blue LEDs. This was a very significant development for the future of LED lighting. The ultra-bright blue LEDs laid the groundwork for later development of cost-efficient and very functional white LED lights. Fixtures and bulbs that use white LED lights are now what you see installed in residential, commercial, and manufacturing sectors in the present day. White LED lights would first appear on the market in 1995.
In 2002, white LEDs for residential applications became available on the commercial market for the first time.
In 2006, LED light efficiency reached 100 lumens per watt. This would be more efficient at the time than any other type of light (apart from high-intensity discharge (HID) lights).
By 2010, there were LED lights being produced that could reach an efficiency of 250 lumens per watt. Nothing else could match it. By 2019, LED lights were becoming the main source of lighting for practically all applications. Other types of lighting such as incandescent, fluorescent, and halogen were slowly being phased out.
The development of LED lighting has progressed over a 100+ year period. It began slowly, in fits and starts, but it quickly developed over the past 30 years. Even more so over the past 10 years.
Today, LED lights have a distinct advantage over other types of lighting in every way.
- They are more efficient, which saves on energy costs.
- They last longer. Up to 100,000 hours, in some cases.
- Almost no energy is wasted on heat.
- They are environmentally friendly because they contain no toxic elements such as mercury. This makes for easy disposal.
- They deliver a higher quality of light that does not degrade over their lifespan.
The advancement of LED lighting technology is still ongoing. Here are some recent developments:
- Glare reduction headlights for cars that also optimize illumination for the driver.
- Li-Fi networks that provide an alternate internet connection outside of standard Wi-Fi.
- Human-centric LED lighting that mimics the color spectrum of the sun.
It’s impossible to know how far the advancement of LEDs will continue to go. What we do know is that LED lights will eventually phase out all other types of lighting. If (and until) a better lighting technology comes along, it will be our primary source of artificial light for years to come.
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About the Author
Neil Peterson is Chief Operating Officer at LED Lighting Supply. He has been active in the LED industry for over 10 years and is responsible for product planning and management as well as revenue and operations at LED Lighting Supply. Much of Neil’s time is focused on customer engagement for large commercial and industrial lighting requirements. When not working, he enjoys family time, camping, fishing, and sports..