Optical System Design for Augmented Reality Head-Mounted Display
In order to meet the application requirements of clear images,appropriate size,and compact structure of helmet displays,a helmet display optical system based on a freeform prism structure was designed using a freeform prism scheme.Adopting a gradual and iterative optimization strategy,optimize the design of the projection system and perspective system.Finally,it was achieved that the modulation transfer function value was greater than 0.3 at 30 lp/mm across the entire field of view.After combining the projection system and perspective system,the overall system operates in the visible light band,with a field of view of 34.7°×20°,an exit pupil diameter of 6 mm,an exit pupil distance of 20 mm,and an overall size of 33.16 mm×23.13 mm×12.3 mm.The design results indicate that this helmet display optical system has a large field of view,large pupil distance,and small size,which can fully meet the needs of users for augmented reality helmet displays.