LED（Light Emitting Diode） Light emitting diode (LED) is a solid-state semiconductor device which can convert electric energy into visible light. It can directly convert electricity into light. The heart of LED is a semiconductor chip. One end of the chip is attached to a bracket, one end is the negative pole, and the other end is connected to the positive pole of the power supply, so that the whole chip is encapsulated by epoxy resin.
Semiconductor chip is composed of two parts, one is p-type semiconductor, in which the hole is dominant, the other is n-type semiconductor, in which the electron is dominant. But when the two semiconductors are connected, a "p-n junction" is formed between them. When the current acts on the chip through the wire, the electrons will be pushed to the p region. In the p region, the electrons will compound with the holes, and then emit energy in the form of photons. This is the principle of LED luminescence. The wavelength of light, that is, the color of light, is determined by the material forming p-n junction.
It is a display screen used to display text, graphics, images, animation, market, video, video signals and other information by controlling the display mode of LED. Because of the advantages of easy control, low-voltage DC drive, rich color performance after combination and long service life, it is widely used in large screen display system of urban projects. LED can be used as a display screen, under the control of the computer, display color changes of video and pictures. LED is a semiconductor that can convert electric energy into visible light.
