LED is a semiconductor device that can directly convert electrical energy into light energy. Compared with other light-emitting devices, it has the advantages of small size, low power consumption, uniform emission, stability, fast care speed, long lifespan, and high reliability. It is widely used in various electronic instruments, audio equipment, computers, etc. for current indication, audio indication, and information flashing.

Luminescence principle: The core structure of a light-emitting diode is similar to that of a general diode, consisting of a PN structure. When a forward voltage is applied to the PN junction of the light-emitting diode, the space charge layer narrows and the carrier dispersion motion is greater than the drift motion, resulting in holes in the P region being injected into the N region and electrons in the N region being injected into the P region. When electrons and holes recombine, energy is released and manifested through luminescence.

There are many varieties of LED light emitting diodes, which differ according to the emission data, including gallium phosphide (GaP) light emitting diodes, gallium arsenide (GaAsP) light emitting diodes, gallium aluminum arsenide (GaAIAs) light emitting diodes, etc; According to the color of the light emitted, there are infrared light emitting diodes that emit red, yellow, green, and invisible to both eyes; If the difference is based on power, it can be divided into small power (HG 400 series), medium power (HG50 series), and high-power (HG52 series) light-emitting diodes: there are also multi-color, color changing light-emitting diodes, and so on.