LED (Light Emitting Diode) light is one of the most important light-emitting structures is the light inside the green bean-sized lamp beads. Although its size is very small, it has a hidden treasure trove.
After the LED bead structure is enlarged, a chip shaped like a sesame seed will be found. This chip structure is extremely complex, divided into several layers: the top layer is called the P-type semiconductor layer, the middle layer for the light-emitting layer, and the bottom layer is called the N-type semiconductor layer. So, how is the light issued by the LED?
From a physical point of view to understand: when the current through the wafer, N-type semiconductor electrons and P-type semiconductor holes in the light-emitting layer violently collide with the compound to produce photons, in the form of photons of energy (that is, we see the light). LED is also known as light-emitting diodes, it is extremely small and fragile, and not convenient for direct use. So the designers added a protective shell for it and sealed it inside so that it constitutes an easy-to-use LED bead. Many LED beads will be connected together, you can constitute a variety of LED lights.
Different materials of semiconductors will produce different colors of light, such as red light, green light, blue light, etc. However, so far there is no one semiconductor material that can send white light. But we usually use white LED light beads and how to produce them?
Here it is necessary to mention a Nobel laureate - Dr. Shuji Nakamura. He invented the blue LED, which also laid a certain foundation for the white LED. Based on this significant contribution, he was awarded the Nobel Prize in Physics in 2014. As for how blue LEDs are transformed into white LEDs, the biggest reason is the extra layer of phosphor in the wafer. The basic luminescence principle does not change much: between the two layers of the semiconductor, electrons, and collisions with holes compound and produce blue photons in the light-emitting layer. Some of the blue light generated will be directly through the fluorescent coating directly emitted; the remaining part will hit the fluorescent coating with the role of yellow photons. Blue photons and yellow photons together (mixed) produce white light.