1 LED chip structure
The most important light-emitting structure of LED (Light Emitting Diode) lamps is the LED chip inside the lamp, which is as small as a mung bean. Although it is small in size, it hides many secrets.
After magnifying the structure of the LED chip, you will find a sesame-sized chip.
This chip structure is very complex and is divided into several layers: the top layer is called the P-type semiconductor layer, the middle layer is the light-emitting layer, and the bottom layer is called the N-type semiconductor layer.
2 Light-emitting principle
From a physics point of view: when electricity passes through the crystal, the electrons in the N-type semiconductor and the holes in the P-type semiconductor collide and recombine violently in the light-emitting layer to produce photons, and the energy is emitted in the form of photons (that is, the light we see).
LED is also called a light-emitting diode. It is very small and weak, and it is not convenient to use directly, so the designer added a protective shell to it and sealed it inside, thus forming an easy-to-use LED chip.
After connecting many LED chips together, you can form a variety of LED lamps.
3 LED lamps of different colors
Semiconductors of different materials will emit light of different colors, such as red light, green light, blue light, Тощо. But so far, no semiconductor material can emit white light.
But how are the white LED chips used in our daily life produced?
4 Production of white light LED lamps
Here we need to mention a Nobel Prize winner, Dr. Shuji Nakamura, who created blue light LEDs, laid a certain foundation for white light LEDs, and won the 2014 Nobel Prize in Physics for this great achievement.
As for how blue light LEDs are transformed into white light LEDs, the biggest reason is that there is an extra layer of phosphor in the chip.
The basic principle of luminescence has not changed much: between the two layers of semiconductors, electrons and holes collide and recombine to produce blue photons in the luminescent layer.
Part of the blue light produced will pass directly through the fluorescent coating and emit directly; the other part will hit the fluorescent coating and react with it to produce yellow photons. Blue photons interact (mix) with yellow photons to produce white light.
If the proportion of blue light is slightly higher, white light with a higher color temperature will be produced; conversely, if the proportion of yellow light is slightly higher, white light with a lower color temperature will be produced.