The basic knowledge that semiconductor materials can produce light has been known for 50 years, and the first commercial diode was produced in 1960. LED is the abbreviation of English LightEmittingDiode (light emitting diode), its basic structure is a piece of electroluminescent semiconductor material, placed on a lead shelf, and then sealed around with epoxy resin to protect the internal core, so the LED seismic performance is good.
The core part of the LED is a chip composed of a P-type semiconductor and an N-type semiconductor, and there is a transition layer between the P-type semiconductor and the N-type semiconductor, called the p-n junction. In the PN junction of some semiconductor materials, the injected few carriers will release the excess energy in the form of light when they are combined with the majority carriers, thus converting electrical energy directly into light energy. PN junction with reverse voltage, a few carriers are difficult to inject, so no light. This kind of diode made of injection electroluminescence principle is called light-emitting diode, commonly known as LED. When it is in a positive working state (that is, with a positive voltage at both ends), when the current flows from the anode to the cathode of the LED, the semiconductor crystal emits different colors of light from ultraviolet to infrared, and the strength of the light is related to the current.