50 years ago, people understood the basics of semiconductor materials can produce light, the first commercial diode is produced on 1960. LED full name is light emitting diode in english, and its basic structure is an electroluminescent semiconductor materials, placed on a wire rack, then sealed with epoxy resin around, namely solid packaging, it can protect the role of the internal core wire.So LED is resistance to shock

The core portion of the diode in LED light is a P-type semiconductor wafer and the N-type semiconductor, between the P-type semiconductor and N-type semiconductor there is a transition layer, called the PN junction. In certain semiconductor materials, PN junction, the injection of minority carrier and majority carrier recombination, when will the excess energy released in the form of light, which converts electrical energy directly into light. When the PN junction reverse voltage, minority carrier injection is difficult, it is not light. This use of injection electroluminescent diodes called the principle of making light-emitting diodes, known as LED. When it is in working condition (that ends with a positive voltage), current from the LED anode to the cathode, the semiconductor crystals from the ultraviolet to the infrared light of different colors, light intensity and current.