The Research And Development Of E50Pure Electric Vehicle Headlamp Led Module

LED (Light Emitting Diode) is a new generation of sources light which has theadvantages of energy saving, environmental protection, high reliability, practicality,decoration and so on. The use of LEDs in car lighting is a global trend and it hasbeen widely applied in the automotive industry. Due to technical difficulties, theinvestigations of LED headlamp are still in its infancy around the world.At present, global pure electric vehicle market continues to grow and blossom.There is huge potential for LED headlamp to be used in the electric vehicle industry.Roewe E50pure electric vehicle has been listed on November2012and its mainperformance indicators have reached the international level of similar products.While it uses traditional halogen headlamps witch is high power-dissipating and notenvironmentally-friendly. LED headlamp with low power dissipation and small sizeare fit for the low power consumption and weight-reducing requirements of pureelectric vehicles, and can effectively improve the car’s mileage. The study ofreplacing traditional halogen headlamp with E50LED headlamp will greatlyimprove lighting quality and performance indicators. In this paper, usingself-developed Roewe E50pure electric vehicles as the application objects, a LEDlight source module suitable for the pure electric vehicle headlamp is developed.As one of the critical technology of automotive lighting, LED headlamp hasmany challenges to overcome. Among them the optical design is one of the keytechnologies. The major factors which have effects on headlamp optical designinclude reflector design and light modules. At present, the low beam light and highbeam light of LED headlamp are separately controlled. Three projection lens unitsand one reflector unit are used in the low beam light. It gets to meet the requirementsof the light intensity distribution by light superimposed of these four units. One unitis used in the high beam light. Hence, the headlamp consists of five units and eachunit has a LED module which consists of2-5chips. This is a common solution of LED headlamp. In order to reduce the power consumption, one LED module thatincludes7chips is applied in this experiment. The functional rules of the LEDmodule are investigated to achieve a low-cost integrated design of the low beam andhigh beam headlamp LED module. The optical simulation and design of the lowbeam and high beam lights are obtained by using no tailgate freeform surfaces LEDreflector technology.LED module is a high-power plane light source which consists of multiple LEDchips with certain geometric distribution. Since it is multi-component compoundsemiconductor device, the parameters of LED chips have a large dispersioncoefficient. Due to the non-uniform of single-chip parameters and the geometricdimensioning error of the multi-chip during the packaging the inconsistencies willdefinitely occur in the parameters of optical simulation. In order to improve theconformity of the LED module, the study of parameter tolerance is very important.In this paper, the parameter tolerance of LED module is evaluated by changing thegeometry of the LED arrays and the fulx of single chip. The values of position errorand chip inconsistencies which can impact the low beam and high beam lightdistribution were determined by optical simulation.