Optimized Design Of Optical Module For Automotive Head-up Display System

In recent years,the number of cars per capita is increasing year by year,while road safety accidents are also increasing.People begin to shift more and more attention to the direction of intelligent driving,using scientific and technological means to ensure people’s driving safety.Head-up Display（HUD）is a kind of intelligent driving assistance system,which can project information such as dashboard,speed and fuel gauge onto the windshield by means of projection,thus reducing the driving blind area caused by lowering the head to check relevant information during driving.Among them,the projection position and the size of the virtual image displayed by the projection can be determined by optical design.Traditional vehicle-mounted Head-up Display system has a short projection distance and less information.In order to integrate with the real scene,automobile HUD technology starts to combine with Augmented Reality technology（AR）to achieve the characteristics of longer distance and greater projection distance.The AR-HUD curved mirror required to achieve these functions will also have a larger area,and the size of the image source will also be larger,which will make the AR-HUD larger and unable to be properly installed into the interior of the car.Therefore,this paper mainly reduces the AR-HUD volume on the basis of ensuring that the virtual image of AR-HUD has clear pixels,longer projection distance and larger projection size.The research content is as follows:First,the development of HUD from military aircraft to civil automobile in recent years is summarized,and the research trends of Combiner HUD（CHUD）,Windshield HUD（WHUD）and Augmented Reality HUD（AR-HUD）are summarized.Secondly,the initial structure of AR-HUD is deduced and determined based on the mathematical model of coaxial and off-axis three-reaction systems.The relationship between Zernike free surface and its coefficients and Seidel aberration is demonstrated in detail,which provides theoretical support for choosing Zernike surface as the hyperboloid surface in this design.By comparing the advantages and disadvantages of four different image sources,TFT-LCD is finally determined as the image source of AR-HUD optical path system from the aspects of economy and practicability.Thirdly,according to the parameters derived and calculated,the AR-HUD optical path system is designed by using reverse design.Some quantitative measurement of AR-HUD optical path design was carried out by professional design software,and the windshield surface profile data provided by the vehicle factory was extracted.The obtained data was input into the optical design software and optimized by evaluation function.After optimization,the imaging quality evaluation and tolerance analysis of AR-HUD optical system are carried out by using the evaluation index and macro function of optical design software.Simulation software is used to simulate and analyze the results of virtual image display.Fourthly,the cause of ghosting in automobile AR-HUD is analyzed,and the ghosting elimination is theoretically derived by geometric method.Finally,the purpose of ghosting elimination is achieved by solving wedge Angle.Dust-proof film design and stray light analysis,so that external light will not cause interference to the HUD interior;The structure design,volume measurement and modal analysis of AR-HUD shell module are carried out by using 3D design software.