How much do you know about the history of LED development?

Light has always been a means of illumination for people to survive, and has accompanied human beings through the long nights for thousands of years. Since the ape man drilled wood to make fire, human beings have experienced the lighting process of animal oil lamps, vegetable oil lamps, kerosene lamps, and candles. Until 1808, British scientist David invented the arc lamp, and human beings have entered the era of electric lighting since the beginning.

For quite a long time before the advent of electric lamps, human beings generally used oil lamps for lighting, and during this period, oil lamps have undergone many improvements. The oil used for oil lamps was changed from animal oil to vegetable oil, which was later replaced by kerosene. The wick has also undergone the changing process of grass, cotton thread, and multiple strands of cotton thread.

Kerosene lamps or gas lamps were the main lighting tools before the popularization of electric lamps. This kind of lamp burns kerosene or gas, so it has strong black smoke and pungent odor, and it is very inconvenient to frequently add fuel and scrub the lampshade. What's more, this kind of light can easily cause a fire and cause a catastrophe.

Accidentally collided with the era of electric lighting

In 1808, British scientist David David made an electric arc lamp, also known as "Arc Lamp", when two carbon rods collided unintentionally, and a strong white light flashed out when he experimented with carbon rods. Candles". However, because of its high power consumption and short lifespan, it was not long before it was launched on the stage of history.

Then came the era of Edison and incandescent lamps that we are familiar with. With the advancement of generator technology and the discovery of material properties, in 1882, Edison established the first power station in New York, making incandescent lamps truly popular in society. universal. The filament of the early incandescent lamp was made of bamboo filament, and then Edison replaced the bamboo filament with chemical fiber, and the quality of the bulb has also been improved to a certain extent.

However, the lighting fixtures that benefit from the material change are not only incandescent lamps. In 1885, three years after Edison established the power plant, the German chemist Awu Aier added a special lampshade to the lamp cap of the original gas lamp. At high temperatures, the metal oxides contained in the lampshade burn to incandescent, resulting in a white light that is far brighter than incandescent lamps.

Until the beginning of the 20th century, since the introduction of tungsten filaments into incandescent lamps, the competition between incandescent lamps and various lamps such as kerosene lamps and gas lamps has won a decisive victory. The application of tungsten wire has strongly promoted the development of the electric lighting industry, and it has been used until now.

Although incandescent light bulbs were later modified to suit special needs, they can be subdivided into general lighting, high and low voltage lamps, halogen lamps, infrared lamps, etc. But generally speaking, incandescent light bulbs cannot meet human needs if they are to be used as lighting fixtures for large rooms or large spaces.

Fluorescent lamps can be said to be a very important invention of indoor lighting, and now the vast majority of nighttime indoor lighting in the world uses fluorescent lamps. Compared with traditional bulbs, fluorescent tubes have several advantages, such as long service life, high luminous efficiency, large illumination area, and can be adjusted to different light colors. The use of fluorescent lamps meets the needs of most human occasions. Although all kinds of electric lamps are still being developed one after another, as of the 20th century, it is still impossible to develop an invention that is more in line with human needs than fluorescent lamps.

 Light-emitting diodes, which began to develop in the late 20th century, brought light to the future of lighting. In 1996, Japan Nichia Chemical Co., Ltd. developed a blue light LED to excite yttrium aluminum garnet phosphors on the basis of GaN blue light-emitting diodes to produce yellow fluorescence, which was then mixed with blue light to produce white light (blue light LED with YAG) Phosphors), opened the prelude to LED into the lighting market.