50 years ago people have learned the basic knowledge of light that can produce light, the first commercial diode generated in 1960. LED is the English light emitting diode, its basic structure is an electroluminescent semiconductor material, placed in a lead on the shelf, and then surrounded by epoxy resin sealed, to protect the internal core Role, so the LED seismic performance is good. The core of the light-emitting diode is composed of p-type semiconductor and n-type semiconductor chip, between the p-type semiconductor and n-type semiconductor has a transition layer, called p-n junction. In some semiconductor materials PN junction, the injection of minority carriers and the majority of carrier recombination will be the excess energy in the form of light released, so that the power directly into light energy. PN junction plus reverse voltage, a small number of carriers is difficult to inject, so do not light. The use of injection-type electroluminescence principle of the manufacture of the diode called light-emitting diodes, known as LED. When it is in the positive working state, the current flows from the LED anode to the cathode, the semiconductor crystal from the ultraviolet to infrared different colors of light, the intensity of light and current.
The features of LED bulbs
1. Voltage: LED using low-voltage power supply, the supply voltage between 6-24V, depending on the product varies, so it is a more secure than the use of high-voltage power supply, especially for public places.
2. Effectiveness: 80% reduction in energy consumption compared to radiant incandescent lamps
3. Applicability: Very small, each unit LED patch is 3-5mm square, so it can be prepared into various shapes of devices, and suitable for easy Change the environment
4. Stability: 100,000 hours, the light failure for the initial 50%
5. Response time: the response time of its incandescent milliseconds, LED light response time for the nanosecond
6. Environmental pollution: no Harmful metal mercury
7. Color: change the current can be discolored, light-emitting diode easily through the chemical modification method, adjust the material band structure and band gap, to achieve red, yellow, green orchid orange multi-color light. Such as the small current when the red LED, with the increase in current, can turn into orange, yellow, and finally green
The article from http://www.new-lights.com