Illumination System Design Of Automotive Laser Headlight Based On Freeform Surface

With the rapid development of science and technology,the field of automotive headlamp lighting has also ushered in a new round of changes,from the earliest incandescent lamps,halogen lamps,and xenon lamps to the most widely used LED lamps.At present,the luminous efficiency of LED lamps is 80-150lm/W,which is not enough to meet the needs of automotive lighting,and is not conducive to energy saving and environmental protection;secondly,the size of the luminous chip of high-power LEDs for vehicles is big,which is not convenient to light distribution design;The lighting distance of LED cannot fully satisfy safe driving.In order to solve the above problems,related researchers began to look for alternatives to LED lights.Because the laser source has the characteristics of high brightness,long irradiation distance,and high light efficiency,which are suitable to solve the above problems,the use of laser light sources in the field of automotive lighting has attracted widespread attention.In this paper,a blue laser light source with a wavelength of 450 nm is selected,and a yellow phosphor of YAG type is selected as the fluorescent material,and white light is prepared according to the principle of light-color mixing.After the blue laser is irradiated to the yellow phosphor,the phosphor is excited to emit yellow light,the blue laser is scattered inside the phosphor,and a certain proportion of yellow light and blue light are mixed to produce the required white light for illumination.According to the light mixing principle of light color,the light distribution curve of white light is obtained.According to the requirements of luminance and light type in GB25991-2010 "Automotive LED Headlights" regulations,the light distribution design is carried out for the high beam and low beam of automobiles.According to the theory of non-imaging optics,first use Snell’s law and the design method of energy mapping to design the reflective free-form surface.According to the real design situation,a relatively novel oblique triangle light source-target mapping design method is proposed.The numerical calculation software Matlab is used to calculate the discrete point;the UG software is used to model and fit all the discrete points to get a smooth and Finally,the free-form reflector model is imported into Light Tools for simulation.According to the simulation results,the free-form surface shape is optimized,and after the energy feedback optimization,the illuminance of each test point and area meets the requirements of the national standard regulations,and the high brightness area is more prominent.The energy utilization rate of the system is 81%.The free-form reflector designed in this paper can complete the preliminary light distribution based on accurate calculation,and optimize the result to meet the requirements of automotive headlight regulations.We verified the feasibility of this method by simulations using the above method.The simulation results show that the designed system is compact and saves design space while meeting the regulatory light distribution requirements,which is important in practical applications.While satisfying the special spot shape requirements for the low beam,it improves the light energy utilization and saves energy and the environment.With the in-depth study of laser automotive headlights,this brighter "eye" will also be common in most models.