Optical Technology Of Automobile Head Up Display System

With the popularization of automobiles,traffic safety has attracted more and more attention.In recent years,automobile safety technology has become a research hotspot all over the world,among which automobile assisted driving technology can provide drivers with necessary driving information to ensure driving safety.The automobile HUD studied in this paper is a visual aided driving system.It can project the driving information into a virtual image at a certain distance in front of the driver,so that the driver can obtain the information of speed,speed,fuel volume,real-time navigation and so on in the state of head-up.Thus,the blind zone time caused by the driver's looking down at the driving information is avoided,and the potential road traffic accidents are reduced.With the iteration of automobile HUD updating,the next generation automobile HUD will be combined with Augmented Reality(AR)technology,which can not only display the instrument and navigation information,but also recognize the real-time road environment outside the vehicle.This kind of automobile HUD is called AR-HUD,which is the frontier field of automobile HUD research and development.Automotive AR-HUD requires that the virtual image display should have a longer visual distance,larger imaging area and more difficult to correct aberrations in its optical system.This paper mainly studies the optical system of automobile AR-HUD.The research contents are as follows:Firstly,the development status of automotive HUD is investigated,and different types of automotive HUD are studied.The market situation of automotive HUD products at home and abroad is analyzed,and the research trends of AR-HUD are summarized.Secondly,the principle of AR-HUD virtual image display is analyzed,and the aberration theory in its optical system is studied.At the same time,the design and application of free-form surface are studied,and the general method of optical design is discussed.Thirdly,the performance requirements of AR-HUD optical system for automobiles are analyzed,and the design index of its optical system is put forward.Taking the front windshield surface of a vehicle as a combination of virtual image and real scene,an AR-HUD virtual image display optical path based on off-axis reflection optical path structure is designed.The optical path is optimized by Zemax,and the imaging quality and tolerance of the system are preliminarily analyzed.Fourthly,the principle of duplication in AR-HUD is analyzed.The method of eliminating duplication is studied,and the corresponding formula is deduced,which provides a theoretical basis for eliminating duplication.Fifthly,according to the requirement of high brightness of automobile AR-HUD source image,the source image display technology of automobile HUD is studied.A microprojection objective for DLP optical machine is designed and its imaging quality is analyzed.Sixthly,the test methods of visual range,field of view angle and Eyebox of AR-HUD virtual image are put forward.The experimental optical path of principle is designed and constructed,and the virtual image experiment is carried out.The results show that the design data are consistent with the experimental data,which shows that the test method is feasible.