Research On Key Techniques Of High Efficiency LED Headlamp

LEDs have many features including energy-savings, long life and quick light-on.Thus they are well suited to be one of the main light sources in the next generation ofautomobile headlamps。Due to the enormous progress in LED development, highbrightness LED’s are now available for automotive front lighting such as low andhigh beam. Nevertheless, the characteristics of LED’s are completely different to thecharacteristics of traditional light sources used in headlamp systems. Thecharacteristic includes not only optical items, but also electrical, mechanical andtemperature issues. These characteristics make new approaches in the field ofautomotive headlamp development necessary.New highly efficient optical design methods to create front light with high brightLED’s are discussed, which fulfils the regulations but consume less power comparedto traditional headlamp will be presented. Communication based on LED of headlampwas preliminarily studied based on the research of driver circuits for high power LEDheadlamp.Heat-pipe is employed to manifest effective heat dissipation.Optical-thermal-electrical performance is simulated with Silvaco TCAD. LED withPhotonic crystal structure was simulated and the results shows that the Photoniccrystal structure enhance the optical efficiency of LED. The mainly innovation pointsin the thesis are as follows.1. For the first time realize the full led headlamp, which fulfills the national standard.Optical design of low beam is developed employing poly-ellipsoid. The systemmodels of headlamp are developed based on optical theory and simulation isperformed employing software ASAP.2. The optical-thermal-electrical model of LED was set up based on thesemiconductor theory and simulations are performed with silvaco TCAD. FDTDmethod is used to analysis the optical extraction efficiency of LED with opticalcrystal structure. Thermal model of LED headlamp based on heat-pipe is built.3. An intelligent lighting control system was designed with the function of visiblelight communication based on the study of automotive LED driver, which rely onthe fast response characteristics of LED. It is of great significance to the newgeneration of smart automotive lightingThe projective low beam employ three multichip LED modules,which consume45watts and give1620lm luminous output, The high beam is realized with twomultichip LED,which consume30watts and give1080lm luminous output. Theresults of thermal test show that when the environment temperature is30oC, thejunction temperature is48oC at100mA current and120oC at700mA current.