Statically Foveated Freeform OST-HMD System with Wide FOV and High Perceived Resolution

Head-mounted displays (HMDs) based on the well-established rectilinear sampling method are subject to the inherent trade-off between wide field of view (FOV) and high spatial resolution. This challenge limits their broader application due to constraints in manufacturing high-resolution display and the substantial data bandwidth required for rendering, storage and transmission. Foveated display technology alleviates this issue by allocating resources differently between the region of interest and the peripheral region. However, most existing solutions rely on dynamic dual-resolution schemes that are costly and complex, requiring multiple displays or optical paths, 2D steering mechanisms, and eye-tracking systems. We propose and demonstrate a novel perception-driven approach to the design of a three-element freeform eyepiece featuring spatially varying optical power. The novel eyepiece enables the creation of a statically foveated optical see-through (OST) HMD, yielding a display of an 80° diagonal FOV and a peak resolution density of 60 pixels per degree (PPD) with a 4K display panel. The display offers high perceived resolution across the FOV with imperceptible or minimal degradation and resolution discontinuity with eye movements. Our approach eliminates the need for eye tracking, scanning mechanisms, or multiple displays, significantly reducing hardware complexity. Compared to the rectilinear sampling scheme offering the same peak resolution density, our system reduces pixel usage by more than 35% or equivalently 4.4 million fewer pixels for the same FOV.