Rsearch Of The Virtual Reality Helmet Display Optical System

Virtual reality(VR)is a computer simulation system that can create the virtual world and make people experience the virtual world.It uses a computer to generate a simulated environment.It is a system simulation of interactive three-dimensional dynamic scenes and entity behavior for a multi source data fusion.It makes users immerse themselves in a virtual world environment.Head Mounted Display(HMD)is an important equipment to realize virtual reality display technology.It generates the digital image by the computer to the human eye which allows the human eye to observe the three-dimensional scene and covers most of the field of view of the human eye.It can simulate a real scene.Through virtual reality technology,specific scenes can be simulated,which is of great help to medicine,aerospace,entertainment,architecture and so on.The immersive virtual reality helmet display technology can enable people to feel the simulation scene and bring people a strong sense of immersion.Immersion is an important criterion to judge the VR helmet display.In order to achieve high immersion the optical system of the helmet display must have a larger field of view angle under the premise of ensuring the image quality.The optical characteristics and the parameters of the large-field immersion helmet display are analyzed in this paper.A LCD screen with a resolution of 2436×1125,a pixel size of 61.33 ?m(IPHONEX screen)and a LCD screen with a resolution of 2688×1242,a pixel size of 61.84 ?m(IPHONEXS MAX screen)are selected as the display screens of the virtual reality helmet display,A two-piece optical lens with an angle of view of 90° and a three-piece optical lens with an angle of view of 100° are designed respectively.In the design process,multiple aspheric surfaces are added to ensure the high image quality and low distortion of the optical system at each field of view angle,which greatly reduces the number of lenses in the optical system.Meanwhile,in order to reduce the weight of the system,the optical system designed in this paper uses resin materials such as low-density APEL,480 R and IKP-4HT.Aiming at the discomfort of people with myopia and hyperopia when using immersive helmet,the diopter adjustment of helmet display is analyzed,and two dioptric correction schemes of HMD optical system are proposed.The tolerance analysis and optical processing of the designed lens are carried out,and finally the imaging experiment of the assembled optical system is performed.The HMD optical system designed in this paper ensures high imaging quality of both center and edge field of view on the premise of large field of view.Compared with the single-chip structure commonly used in the market,two-piece or three-piece structure can better correct all kinds of aberrations and obtain a larger field of view.Compared with the structure with more lenses,the two-piece or three-piece structure has a more compact structure,lighter weight and lower manufacturing cost,which can be applied to the helmet display system of the new generation of virtual reality equipment.