Research On Key Technologies Of Automobile Laser Headlamps

Automobile is an indispensable means of transportation in our life,and the headlamp is the most important optical device of the whole body.The automobile headlamp has undergone the renewal of incandescent lamp,halogen lamp,xenon lamp,LED and other light sources.The next generation of automobile headlamp is the automobile laser headlamp introduced in this paper.The automobile headlamp with laser source has the advantages of high brightness,long working time,long irradiation distance and high photoelectric conversion efficiency.As the development direction of the next generation automobile headlamp,German BMW and Audi have equipped laser headlamp on some models,but there are no relevant achievements in China.Therefore,the research on laser automobile headlamp has high practical value.Laser headlamp technology is in the exploratory stage,involving optics,electricity,chemistry and other disciplines.This paper studies from three parts:beam shaping,light source chroma,light source driver.Beam shaping part:By using combination lens method,optical fiber coupling method and meshing method respectively,the illumination results satisfying the requirements of national standard for light distribution are obtained on the receiving screen with a distance of 25 meters from the light source and a size of 5 meters*5 meters.Light source chromaticity:white light which meets the requirements of automobile lighting is obtained by using laser source to excite phosphor.The light source is PL-TB450B blue laser,and the phosphor is yellow aluminate phosphor YAG-05.Three different structures were designed:transmission type,reflection type and transmission-reflection type.The mixing mode of light source and phosphor was studied.It is concluded that simple transmission or mixing of light through a single reflection can not obtain white light which meets the lighting requirements.In practical application,it needs to undergo multiple reflections to make blue light and yellow light fully mix.At the same time,the molar concentration of phosphor which affects the color temperature of white light was studied.Through a number of simulation experiments,the molar concentration of phosphor was 0.00354 mol/L when the color temperature of emitting light was the best.Light source driver part:Because of the laser diode characteristics and the single conductivity,a constant current source circuit based on AMC7150 chip is designed.The working voltage and current of the driving circuit are 12V and 1.2A,which meet the requirements of the laser source.