Ultra-wide-angle holographic near-eye display with spherical illumination

This work develops an accurate and efficient computer generation hologram (CGH) method that supports a wide-angle field of view (FoV) or ultra-wide-angle FoV using spherical illumination. The method calculates the CGH in the frequency domain, which means that 3D object geometry information is updated in the frequency domain only for the frequency range of an object point sub-hologram. The bandwidths of these sub-holograms are shown to be narrow, providing CGH with efficient computation. Derived equations show that CGH with spherical illumination generates an image with highly inhomogeneous and highly anisotropic resolution, which depends on the size of the sub-hologram that is a function of illumination sphericity and the field coordinate. Two versions of the CGH algorithm are developed: one allowing a maximum doubling the native FoV and the second allowing a larger expansion of FoV. Finally, the spherical illumination method is shown to improve the performance of a color display. It is shown that it equalizes the FoVs of RGB holograms. The work is illustrated with experiments and simulations; the experiment shows the increase of FoV from 14.7° × 31.5° to 65.7° × 51.2°, and the simulation from 29° × 29° to 60° × 97.2°