The Evolution of LED Lighting
Today, LED is hailed as the most energy-efficient light source. It consumes 80% less energy but provides brighter and more focused light with a lot less glare and heat loss. It lasts longer, which makes hard-to-reach lights easier to maintain. And because it is energy-efficient, it is more sustainable and environmentally friendly. LED is the lighting of the future.
But how was LED invented and how has the technology improved since then? This article explains the evolution of LED light.
LED stands for “light emitting diode”. A semiconductor takes the electricity emitted by a diode into electricity without producing any heat. This is based on the principle of electroluminescence, or when a material gives out light when it exposed to a strong electric field or current.
Scientist Henry Joseph Round first observed this in 1907, when he observed a faint light coming from electrically charged silicon carbide. However, the light was too weak for practical application, and he did not do any other research on it. Thirteen years later, Bernhard Gudden and Robert Wichard Pohl decided to continue his work but experimented with other materials like zinc sulfide with copper. They also failed to produce a bright light, but other scientists became interested in their research. In 1936, George Destriau replicated their results with zinc sulfide powder and published his findings in a scientific journal, coining the term “electroluminescence” to describe what he observed.
But for the next 25 years, no scientists could produce enough light for it to be of any practical purpose. The breakthrough came only in 1961 – and by accident too! Robert Biard and Gary Pittman were working on a laser diode and generated infra-red light. It wasn’t a very bright light, but now researchers could now focus on working on more efficient electricity sources. In 1962, Nick Holonyak, Jr. was able to make the red light visible to the naked eye. That is why he is now remembered in the evolution of LED light as the “Father of the Light-Emitting Diode.”
From then on, scientists have worked on developing semiconductors that could increase and optimize the light that was produced. They discovered gallium phosphides were an efficient material for red LEDs. They later produced orange LEDs, and eventually, M. George Crawford of the Monsanto Company was able to combine this with a green light to make a pale yellow LED. They were able to manufacture this for consumer use.
From there, the evolution of the LED light included improving the brightness and intensity of developing new colors. Companies like Fairchild Optoelectronics were also able to bring down the cost. In 1994, Shuji Nakamura found a way to use gallium nitride to create ultra-bright blue LEDs. It was a critical milestone because by combining it with fluorescent phosphors, it could emit the pure white LEDs that are now being used today.
The evolution of LED light was fast and unstoppable since then, as it gained support from the U.S. Department of Energy and other environmental and energy groups.