by Charles Miller

LED, which stands for light-emitting diode, is a solid-state semiconductor that glows when a voltage is applied. For purposes of illumination, LEDs are much more efficient than incandescent light bulbs that waste about 98% of their energy consumption by generating heat rather than light. LEDs can actually be cool to the touch while brightly outputting many lumens of light.

Based on the effect of electroluminescence, LEDs emit light when electricity is passed through elements or compounds, such as aluminum-gallium-arsenide. This effect has been known to electronics researchers since first observed in 1907 when Englishman Henry Joseph Round noted some of the components in the Marconi wireless glowed in the dark. Russian radio researcher Oleg Vladimirovich Lossev also studied the phenomena in the 1920s but it was not until 1961 that Robert Biard and Gary Pittman accidentally invented then patented an infrared LED for Texas Instruments. This first LED was infrared, meaning that it was beyond the visible light spectrum humans can see.

In quick succession over the next few years other inventors discovered gallium arsenic (GaAs) could be used to produce visible red light, and gallium phosphide (GaP) produced a green LED. This made it possible to produce flat screen monitors, but the early ones were only monochrome green or amber; not full color. Something very important was missing.

The human eye perceives the three additive primary colors (red, green, and blue) in various combinations and intensities in order to see the full range of colors found in nature. If you have red, green, and blue lights you can mix them to create a million colors, but if you have only red and green you can mix those two colors to get little more than various shades of yellow. Without blue there can be no magenta, cyan, or any of the other colors on that side of the color wheel.

Finding a way to make that missing blue LED became the holy grail of inventors and researchers for several decades. It was said that whoever discovered how to make a blue LED could reap billions. RCA Corporation failed to get that memo because one of their researchers actually did create a rudimentary blue LED in 1972 but the project was abandoned and forgotten in favor of that company’s failed competition with IBM in the computer market.

It was left to Japanese-American electronic engineer and inventor Shuji Nakamura to make the major breakthrough with his discovery that indium gallium nitride (InGaN) could be used to create a blue LED. Working for the Nichia Corporation in Japan, Nakamura ultimately self-funded the last years of his work when the company ordered his project discontinued. In 1993 he succeeded. The blue LED was the last piece of the puzzle making it possible to use LEDs to create all the colors of the visible light spectrum. Within a decade everything from street lights to flat-screen televisions to smart phones were changing to LED.

Regrettably as is so often the case with the inventors of world-changing innovations, Shuji failed to receive the financial rewards he was due. He sued his former employer and was awarded ¥20 billion (with a “B”) yen then the largest such verdict in Japanese history, but after years of appeals settled for ¥840 million yen (U.S. 8.1 million dollars) which just happened to be almost exactly what he owed his lawyers.

Finally in 2014 the Swedish Academy of Sciences awarded the Nobel Prize in Physics jointly to Isamu Akasaki, Hiroshi Amano, and Shuji Nakamura saying that “Incandescent light bulbs lit the 20th century; the 21st century will be lit by LED lamps.” and “The LED lamp holds great promise for increasing the quality of life for over 1.5 billion people around the world who lack access to electricity grids: due to low power requirements it can be powered by cheap local solar power.”

We can all appreciate that, as well as give thanks to Shuji that the screens of all our smart phones are full-color and not monochromatic.

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Charles Miller is a freelance computer consultant with decades of IT experience and a Texan with a lifetime love for Mexico. The opinions expressed are his own. He may be contacted at 415-101-8528 or email FAQ8 (at) SMAguru.com.

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