Study On The Optical-thermal Associated Characteristics Of LED Headlamp Under The Action Of Ionic Wind

In recent years,with the rapid development of the automobile industry,the intelligence and shape of automobiles have become the main criteria for consumers to choose cars.As an important part of the overall appearance and the driving safety of automobiles,the choice of car headlights and the design of the exterior are particularly important.Traditional light sources such as incandescent lamp,halogen lamp and xenon lamp can also achieve good lighting effect,but in today's energy-saving,environmental protection and increasing demand for intellectualization,traditional light sources have been difficult to adapt to the trend.The use of high-power LED as automotive headlamp has attracted the attention of automobile manufacturers around the world.Because of its unique structure and working principle,LED enriches the shape design of automotive headlamp and meets the requirements of automotive intelligence.However,when high-power LED works in harsh environment,the chip junction temperature will rise.If the junction temperature of LED chip cannot be effectively controlled,the lighting performance and service life of LED headlight will be greatly affected.It is particularly important to find an effective heat dissipation technology for high-power LED chips.In view of the shortcomings of traditional heat dissipation technology used in high-power LED heat dissipation.Based on the principle of corona discharge,a‘needle-net'CDIW radiator is designed.The distribution of ionic wind in the discharge space is studied by the means of experiments and calculations.The influence of the distribution of emitter needle electrodes,radius of curvature,applied voltage and power polarity on the heat dissipation performance of CDIW radiator was studied,the optimum structure of CDIW radiator was obtained.The thermal and optical characteristics of high power LED chips such as junction temperature,luminous flux,correlation color temperature,color rendering index and luminous intensity were measured under the optimized radiator.The optical-thermal correlation characteristics were studied to verify the feasibility of ionic wind cooling technology for high power LED headlamp heat dissipation.The research shows:?1?The optimized ionic wind generator uses a thin needle-shaped discharge electrode?80?m,18 mm between adjacent needles?,the mesh electrode(20 in^-2)with small grid density and the discharge gap is 5 mm with negative corona discharge.?2?When the corona discharge power is 3 W,the junction temperature of the LED chip can be effectively reduced by using the optimized ionic wind generator and the junction temperature can be controlled at about 30°C.?3?The optimized ionic wind generator can effectively control the blue shift of the luminosity coordinate of the LED headlamp source.The luminous flux attenuation is small,the correlation color temperature and color rendering index have no obvious change.?4?Under the action of ionic wind,the LED headlamp has a wider range of luminous intensity,more symmetrical and uniform,high brightness center and weak side edge,which is more suitable for driving beam illumination.