LED light-emitting diode, is to use semiconductor homogeneity, metal - semiconductor PN junction, heterogeneous PN junction (MS), metal insulator - semiconductor (MIS) made of light-emitting devices. The operational principle and the characteristics of some electrical and general crystal diode is the same, but with different crystal materials. Leds including visible and invisible light, laser, such as different types, days in common for visible light leds. Leds luminous color depends on the material, there are red, orange, yellow, green, blue, purple, blue, white, full color, and other color, can be made into rectangular and circular shapes. LED has a long life, small amounts of light body, small power consumption (energy conservation), low cost, and low operation voltage and high luminous efficiency, luminous echo time very short, wide operation temperature range, light color purity, firm structure, high impact (oscillation), function stable and reliable, and a series of features, more the favour of people.

Because the LED light close to "dot" light source, lamps and lanterns design more convenient, but, if appears as a large area, current and power consumption are larger. LED in general can be used in the light of electronic equipment, digital tube, plate appeared, such as equipment and photoelectric coupling equipment, are also commonly used optical communication, etc., as well as building summary, amusement park, billboards, street, stage and other places of decoration