LED is the abbreviation of Light Emitting Diode, which is a semiconductor solid light emitting device. It uses a solid semiconductor chip as a light-emitting material. When a forward voltage is applied at both ends, the carriers in the semiconductor will recombine and cause photon emission to produce light. LED can directly emit red, yellow, blue, green, green, orange, purple and white light. UV-LED refers to the LED emitting ultraviolet light, referred to as UV-LED.