LED Technology Development History

LED is the abbreviation of Light Emitting Diode, and its Chinese name is light-emitting diode. Its unique optoelectronic properties make it widely used in many fields and equipment, such as various electrical remote controls, equipment indicator lights, LED lighting and displays, etc.

In 1907, scientists at the Marconi Laboratory in the UK first deduced that semiconductor PN junctions can emit light under certain conditions, laying the physical foundation for the invention of LED.

In 1927, Russian scientists independently produced the world’s first LED, and their research results were published in scientific magazines in Russia, Germany and the UK. However, for a period of time afterwards, people did not realize its huge potential and application value, and LED only remained at the technical level.

In 1955, physicists at the Radio Corporation of America first discovered the infrared radiation effect of gallium arsenide (GaAs) and other semiconductor alloys, and physically realized the light emission of diodes. Because it emits infrared rays instead of visible light, this research is of great significance to the development of LED.

In 1961, scientists at Texas Instruments (TI) discovered that gallium arsenide would release infrared radiation when an electron flow was applied. They were the first to produce infrared LEDs for commercial use and obtained a patent for the invention of gallium arsenide infrared LEDs. After official commercial use, infrared LEDs were widely used in various sensors and optoelectronic devices, such as remote controls for various household appliances.

In 1962, researchers at General Electric (GE) invented an LED that could emit red visible light and was called the “father of light-emitting diodes.” At that time, LEDs had to be made by hand and each sold for as much as $10. In 1963, the researcher left General Electric and became a professor in the Department of Electrical Engineering at the University of Illinois, further advancing LED research.

In 1972, the researcher’s students invented the first orange-yellow LED, which was 10 times brighter than the previous red visible light LED, marking an important first step for LEDs to improve luminous efficiency.

In the late 1970s, people had developed LEDs that produced red, orange, yellow, green, and emerald green light, but there were no blue or white LEDs. Although full-color LED display was not possible at the time, the luminous efficiency of LEDs was greatly improved. In the mid-1970s, when LEDs produced green, yellow, and orange light, the luminous efficiency was 1 lumen/watt; by the mid-1980s, the use of gallium arsenide and aluminum phosphide led to the birth of the first generation of high-brightness red, yellow, and green LEDs, with a luminous efficiency of 10 lumens/watt.

In 1993, while working at Nichia Chemical Corporation in Japan, Shuji Nakamura invented blue LEDs using gallium nitride (GaN) and indium gallium nitride (InGaN). Before the emergence of blue LEDs, it was impossible to synthesize white light through the RGB system, and the LED light efficiency and brightness were not high, so it could not be used in the lighting field. 

In 1995, he invented green LED using indium nitride; in 1998, he made white LED using red, green and blue LEDs. The successful development of green and white LEDs marked the official entry of LED into the lighting field and was the most critical milestone in the development of LED lighting. Shuji Nakamura was also known as the “father of blue, green and white LEDs”.

In 1996, Nichia Chemical Industries, Ltd. first applied for a patent for the invention of white LED in Japan. The blue light emitted by the chip and the yellow light emitted by the activated phosphor complement each other to form white light. The emergence of blue and white LEDs has broadened the application field of LEDs and provided a technical basis for full-color LED displays, LED lighting and other applications.

By the early 21st century, LEDs could emit light of various colors in the visible spectrum, and could also display infrared and ultraviolet rays, with a luminous efficiency of more than 100 lumens/watt.