LED light is an
electroluminescent semiconductor material chip, with silver glue or
white plastic curing to the bracket, and then use a silver wire or gold
wire connected to the chip and circuit board, surrounded by epoxy resin
sealed, to protect the internal core Role, and finally install the shell, so the LED lamp seismic performance is good.
(Light Emitting Diode), a light-emitting diode, is a power can be
converted into visible light solid-state semiconductor devices, it can
be directly converted into light. The heart of the LED is a semiconductor chip, one end of the chip
attached to a bracket, one end is negative, the other end connected to
the positive power supply, so that the entire chip is encapsulated by
Semiconductor chip consists of two parts, part of the P-type semiconductor, in which the dominant hole inside, the other end is the N-type semiconductor, mainly electronic here. But when the two semiconductors are connected, they form a P-N junction between them. When the current through the wire acting on the chip, the electron will be pushed to the P area, in the P area with the hole in the electronic composite, and then will be issued in the form of photon energy, which is the principle of LED light. And the wavelength of light is the color of light, which is determined by the material that forms the P-N junction.
LED can be issued directly red, yellow, blue, green, blue, orange, purple, white light. 
The initial LED used as instrumentation indicator light source, and later a variety of light color LED traffic lights and large area display has been widely used, resulting in a very good economic and social benefits. To 12-inch red traffic lights, for example, in the United States was originally used long life, low light performance 140 watts incandescent light as a light source, it produces 2000 lumens of white light. After the red filter, the light loss of 90%, leaving only 200 lumens of red light. In the new design of the lamp, Lumileds company uses 18 red LED light source, including circuit losses, including a total of 14 watts of electricity, you can produce the same light effect. Automotive lights are also important areas of LED light source applications.
For general lighting, people need a white light source. 1998 white LED development success. This LED is the GaN chip and yttrium aluminum garnet (YAG) made together. GaN chip blue (λp = 465nm, Wd = 30nm), high temperature sintered Ce3 + -based YAG phosphor is excited by this blue light after the yellow light, the peak 550nLED lamp m. The blue LED substrate is mounted in a bowl-shaped reflective cavity, covered with a thin layer of resin mixed with YAG, about 200-500 nm. The blue part of the LED substrate is absorbed by the phosphor and the other part of the blue light is mixed with the yellow light emitted by the phosphor to obtain white light.
For InGaN / YAG white LED, by changing the chemical composition of YAG phosphor and adjust the thickness of the phosphor layer, you can get the color temperature of 3500-10000K colored white light. This white light through the blue LED method, simple structure, low cost, high technology maturity, so the most use.