October 2013 saw the 50th anniversary of the invention of the LED (light-emitting diode), attributed to the General Electric engineer Nick Holonyak. However, in order to tell the complete story of this lighting system, which now forms an integral part of our daily lives, it seems we also have to consider the work of earlier and later researchers. Let’s look at them in chronological order.
Henry Joseph Round (1881-1966)
The first descriptive note on electroluminescence, the basic principle of LEDs, was written by this British scientist when he observed that certain semiconductors emit light when an electric current passes through them. Round, one of the pioneers of radio, observed the phenomenon while applying tension to semiconductors in an attempt to improve the amplification of radio signals. He sent his descriptions to the magazine Electrical World and they were published on 9th February 1907.
Henry Joseph Round was Marconi’s assistant. He worked on the first British radio transmitter and participated in the development of what we now know as SONAR.
Oleg Vladimirovich Lósev (1903-1942)
Losev published the first published study on LEDs in 1927, initially in a Russian newspaper and then in various British and German publications. He was a highly talented scientist and researcher, specialising in telecommunications and electronics. Losev noticed something that Henry Joseph Round had previously observed: that the semiconductors used in radio receivers emitted light when an electric current passed through them. He then built a crystal diode with zinc oxide and silicon carbide which, as he had imagined,emitted photonswhen a current was passed through it. Losev patented the “Light Relay” and predicted its use in telecommunications. The scientist died in 1942, aged 39, before he could develop his invention. (Wikipedia).
Nick Holonyak (1928)
While working for General Electric, the North American engineer invented the first LED in the visible spectrum in 1962. One year later, he stated in Reader’s Digest that LED lamps would substitute the incandescent bulbs invented by Thomas Edison.
After giving electrical engineering and information technology classes at the University of Illinois, Holonyak has now spent over a decade exclusively on research.
He is also the father of the quantum dot laser and he develops LED applications at the Philips Lumileds Lighting Company.
We recommend the interview GE Lighting conducted with him to celebrated the 50th anniversary of his discovery (see video) and the article they published to mark the occasion.
Shuji Nakamura (1954)
To this electronic engineer, professor at the University of Santa Barbara (UCSB), we owe the first high-brightness GaN LED and the discovery of the blue LED light. This work enabled the later work on the white LED light which is used for illumination.
Nakamura also developed ultraviolet LED, which enables the sterilization of water. He also discovered the blue laser, which led to Blu-ray technology: this quintuples the storage capacity in devices such as DVDs.
Advantages and Applications of the “Ultimate Lamp”
When referring to LED technology, Nick Holonyak has called it the “ultimate lamp” because “the current itself is the light.” It is highly efficient compared with other technologies, both in terms of duration and of energy consumption (75% less than incandescent sources). Moreover, the LEDs do not heat up, they guarantee instant optimum light performance, they are not affected by vibrations, they can be used in very small devices, and their light is similar to that of daylight, thereby reducing sight tiredness when driving.
LEDs are present everywhere in our daily lives: in mobile, tablet, computer and television screens, in microscopic surgical equipment, on runways, on roads, in all types of signs, in cars, in decoration, in radars and military equipment, on information panels, in printers, and so on.
At Inmesol, we manufacture our ecological and transportable lighting towers using LED technology. Because they resist vibrations, the lamps mean these towers can be used for emergencies as they can be transported on the road at higher speeds than usual. Another advantage is that they reduce the power generator’s consumption of diesel as they consume less energy than incandescent lamps. The energy saved can be used to fuel other auxiliary charges.
Wikimedia Commons. Downloaded from: http://en.wikipedia.org/wiki/File:HJ_Round.jpg#filelinks
Wikimedia Commons. Downloaded from: http://www.computer-museum.ru/connect/losev.htm