Light Emitting Diode LED

Light-emitting diodes, referred to as LEDs for short, are commonly used light-emitting devices that emit energy through the recombination of electrons and holes, and are widely used in the field of lighting. [1] 
Light-emitting diodes can efficiently convert electrical energy into light energy and have a wide range of uses in modern society, such as lighting, flat panel displays, and medical devices. [2] 
This kind of electronic component appeared as early as 1962. In the early days, it could only emit low-luminosity red light. Later, other monochromatic versions were developed. The light that can be emitted has spread to visible light, infrared and ultraviolet light, and the luminosity has also increased to a considerable luminosity. And the purpose is also as indicator light, display board, etc. from the beginning;
With the continuous advancement of technology, light-emitting diodes have been widely used in displays and lighting.

Light-emitting diodes are simply referred to as LEDs. It is made of compounds containing gallium (Ga), arsenic (As), phosphorus (P), nitrogen (N), etc.
When electrons and holes recombine, it can radiate visible light, so it can be used to make light-emitting diodes. Used as indicator lights in circuits and instruments, or composed of text or digital displays. Gallium arsenide diodes emit red light, gallium phosphide diodes emit green light, silicon carbide diodes emit yellow light, and gallium nitride diodes emit blue light. Due to chemical properties, it is divided into organic light-emitting diode OLED and inorganic light-emitting diode LED.