Angular-splitting hologram for high-quality eyebox expansion in near-eye displays.

Abstract

The eyebox of holographic near-eye displays is fundamentally constrained by the limited space-bandwidth product of spatial light modulators. Conventional non-diffusive holograms trade a narrow eyebox for high-quality reconstruction, whereas diffusive holograms expand the eyebox through uncontrolled spreading at the expense of severe speckle noise. To address this limitation, we propose an angular-splitting hologram method that reconstructs target images using object light waves from multiple directions. In the frequency domain, this multi-directional encoding manifests as multiple concentrated energy centers, each corresponding to an independent viewing window. Coexisting, horizontally distributed observation windows can effectively expand the overall eyebox. Each window retains the low-speckle reconstruction of non-diffusive holograms, enabling high-quality image reconstruction across the enlarged eyebox. Numerical simulations and optical experiments demonstrate that the angular-splitting hologram expands the eyebox range while preserving high-quality image reconstruction. This offers an effective strategy toward high-quality holographic near-eye displays with an enlarged eyebox.