What is behind the colorful LED rainbow?
According to a report, about a quarter of electricity consumption in the world owes to lights. As the newest generation of lights, LEDs can produce more lumens per watt, consume less energy and have longer life expectancy, which has won these products a good reputation and led the trend in lighting industry.
In 1907, Henry Joseph found the phenomenon that light can be emitted through electricity, which was revolutionary but failed to be applied. Then in 1920s, the yellow phosphor was extracted but with a dim lighting effect. The first LED was invented in the coming of 1960, which can be sensed by equipment but it was invisible for eyes. Later the visible LED came out and the red light became available and even with a high brightness. Later, the orange light and the green light LED appeared. Since then, the LEDs were all made up of phosphide. However, it took scientists decades to study and manufacture the blue LED because of the challenges of creative technology and the unique materials. Blue LEDs are made of nitrides and metallo-organic compounds and takes the method of MOCVD.
Last year, the laurel of Nobel Prize Physics was conferred on scientists: Isamu Akasaki, Hiroshi Amano and Shuji Nakamura, who invented blue LED in 1990s. Why is blue LED such a great breakthrough that wins Nobel Prize? Since its birth, the most influential effect is that it makes our lives brighter with white lights and more colorful with adding more colors through the RGB color model.
Like sunshine, people need pure white lights most. There are three ways to produce the white Led bulbs. One is a combination of RGB color. When our eyes see these three colors together, they will spontaneously transform the RGB color into a white light and let us have a sense of seeing the white light. The second way is the most common one consisting of a blue LED and yellow phosphor. The last way is a combination of UV LED and red, blue and green phosphors.
The production of white lights expounds the significance of blue LED lights. As blue light consists of the lowest energetic photons among the RGB, it demand highly on workmanship and materials of chips and packaging.
Now that LED products are penetrating into our lives, people tend to have another concern on LED lights, that is, the blue lights from LED might impair eyes. Scientists say that only the excessive blue photons will cause bad vision and most led products in the market are certified with acceptable quality.