Dual-Focal Plane Augmented Reality Near-Eye Display Adopting Liquid Crystal Variable Retarder

Near-eye display (NED) technology has advanced significantly in recent years and is now a vital tool for communicating with the metaverse. It has numerous uses in the military, healthcare, entertainment, and education sectors. Nevertheless, the majority of current near-eye display systems only have a fixed focal plane for imaging, making it impossible to accurately depict the relationship between focus and vergence. During 3D imaging, this may cause adverse effects in observers, including diplopic vision, visual fatigue, degraded oculomotor response, and errors in depth perception. In this article, we develop an optical see-through near-eye display (OST-NED) system with an optical power of 0.25 and 5 diopters by combining a liquid crystal variable retarder (LCVR) with a polarization catadioptric optical system. The observation range of the human eye extends from near-infinity to the near point, which is covered by this range. The optical principles of the dual-focal NED system are first introduced in the article, after which mathematical formulas for the virtual image distance and the optical power of the system are derived. We explain the creation of the initial optical system structure, optimization design, and the process of image quality analysis. The final system offers high image quality with a diagonal field of view (FOV) of 48°, an exit pupil diameter (EPD) of 10×6 mm, and an eye relief (ERF) of 20 mm, which is based on a 0.39-inch micro-display. The article concludes with simulation results of imaging effects at various virtual image distances, demonstrating the high performance and wide applicability of the system.