LED is an abbreviation of the English name "Light Emitting Diode" and is a particular type of semiconductor diode that emits light when an electric current is passed through it.
The light it emits can be in the visible spectrum, as well as in the infrared and ultraviolet. Even though LED today has a wide application, such that it is within reach of every user at any time, the technological path of creating the first LED lamp as we know it today was highly complex and time-consuming.
How was the LED light bulb created?
The electric bulb was used for lighting almost the entire 20th century, but its two most significant drawbacks are energy inefficiency and short shelf life. A classic light bulb uses most of the energy to create thermal energy - as much as 95% - while only five percent goes to producing heat.
Fluorescent lighting (often called neon) began to be used in the 1930s. Although compared to electric bulbs, fluorescents are much more efficient, they are certainly not an ideal solution because they contain toxic mercury and are prone to flickering. Because of all this, a better solution was sought.
Garry Pitman and James Beard invented the light-emitting diode quite by accident while trying to construct a laser diode. It was in 1961.
The first LED emitted infrared light, invisible to the human eye, which later found application in various devices such as remote controls. Yes, the remote control is nothing but an LED!
What happened after that?
Over the next few decades, research and invention made red and green LEDs visible to the human eye, but scientists could never create the blue LED that would be the turning point to the much sought-after white LED.
The biggest companies that produced electrical devices tried with all their might to find a way to create a blue LED. The critical element was a chemical compound called gallium nitride, which proved difficult to produce in the laboratory. After nearly 30 years of unsuccessful attempts, scientists turned to other more promising semiconductor materials.
A small Japanese company called NICHIA and Japanese physicist Shuji Nakamura are also involved in the race to find a blue LED. He first tried to create a blue LED on his own, but he had a minimal budget, so he was forced to develop red and infrared LEDs, practically out of nothing. He used parts that he found in junkyards, basements, and other places and modeled them by hand.
Source: The Japan Times
What did Nakamura achieve?
Painstaking and long-term work did not lead him to the desired result, but it gave him a lot of experience and knowledge about the creation of LEDs. In addition, Nakamura was determined in his idea to use the compound gallium nitride in the product of the blue LED, which at the time, in scientific circles, was already characterized as an impossible solution.
A small budget and the use of a compound almost impossible to produce did not discourage this scientist because he had a powerful personal motive for the invention of the blue LED - his doctoral dissertation.
The doctorate ruled
Namely, Nakamura needed a doctorate to continue his university career in America. He opted for this problematic technology because of the small number of works with which it was processed until then.
Most companies during the 1980s created LED materials using commercially available expensive equipment, which proved inefficient when making blue LEDs and caused frequent explosions in the laboratory.
Nevertheless, Nakamura convinced the leaders of the company NICHIA, where he worked, to buy the equipment necessary to produce the compound that would lead to the creation of the blue LED. Instead of starting from scratch like the first time, he modified the equipment he bought.
Hard work results in rewards
After only one year, he produced gallium nitride in laboratory conditions. His method led to a reduction in the cost of manufacturing an LED chip that makes bluish light. The white LED in its housing contains this LED chip, which gives out bluish light, covered with a phosphor layer that converts bluish light into white light.
Small, energy-efficient, and highly bright LEDs started the lighting revolution and are now used in almost every electrical device such as telephones, televisions, computers, and other electronic devices. In 2014, Shuji Nakamura received the Nobel Prize in Physics for his inventions, along with Isamu Yakasaki and Hiroshi Amano.
Thanks to persistence and the desire to leave something beneficial to the world, we have LEDs as the most efficient and best light source today. And we can combine it however we want and wherever we want.