Optical See-through Head-mounted Displays with Wide Field of View and Hard-edge Occlusion by Using Paired Conical Reflectors

Optical see-through head-mounted displays (OST-HMDs) are actively developed in recent years. An appropriate method for mutual occlusion is essential to provide a decent user experience in many application scenarios of augmented reality (AR). However, existing mutual occlusion methods fail to work well with a large field of view (FOV). In this paper, we propose a double-parabolic-mirror (DPM) structure that renders hard-edge occlusion within a wide FOV. The parabolic mirror increases the numerical aperture of the system significantly, and the usage of paired parabolic mirrors eliminates most optical aberrations. A liquid crystal on silicon (LCoS) device is introduced as the spatial light modulator (SLM) for imaging a bright see-through view and rendering sharp occlusion patterns. A loop structure is built for eliminating vertical parallax. The system is designed to obtain a maximum monocular FOV of H114° X V95° with hard-edge occlusion and an FOV of H83.5° X V53.1° is demonstrated with our bench-top prototype.