Light emitting diode (LED) is a photoelectric element including a III-V compound semiconductor material, its core is the PN junction . The forward voltage, electrons injected from the N area P area , hole injection from the P region N region , part of the minority carriers into each other 's region and majority carrier recombination to emit light. PN junction is formed of material properties ( band gap ) determines the wavelength of light emitted , for visible light , which determines the color of the light.

The main features of LED are: small size, low power consumption, long life, high brightness low heat , environmental protection and durable. Under proper current and voltage , LED life of up to 100,000 hours .

LED classification and application

Depending on the type of light emitted , LED can be divided into visible and invisible LED LED two kinds.

LED visible light including red , orange, yellow , green, blue , violet LED. Wherein the red LED material GaP ( binary ), AlGaAs ( ternary system ) and AlGaInP ( quaternary ) based ; blue / white LED GaN -based material .

LED is widely used, including:

• LED display: indoor and outdoor billboards, sports scoreboard , displays and other information ;

• the signal light: the major , in the city of the city's traffic lights , highways , railways and airports lights, electronic equipment function indication ;

• color lighting : outdoor landscape lighting and interior lighting ;

• special general lighting : portable lighting ( flashlights, headlamps ) , illumination lighting ( gallery lights, number plate lights , court lights ) , reading lights ( plane, train, car reading light ) , light microscope , camera flash , lamp , street lamps ;

• security lighting : lamp , explosion-proof lights, emergency lights , security indicator lights ;

• the backlight : LCD monitors, LCD TV backlight.

• vehicle lights : Includes interior lighting and exterior lighting , including the car dashboard , Denso product indicator ( switches , audio, etc. ) , switch the backlight , reading light and external brake lights , tail lights, side lights and head lights.

• other applications : for consumption , such as children's shoes flash , LED Christmas tree lights.