Eyebox expansion with accurate hologram generation for wide-angle holographic near-eye display

Abstract

Small eyebox in wide-angle holographic near-eye display is a severe limitation for 3D visual immersion of the device. In this paper, an opto-numerical solution for extending the eyebox size in these types of devices is presented. The hardware part of our solution expands the eyebox by inserting a grating of frequency fg within a non-pupil forming display configuration. The grating multiplies eyebox, increasing the possible eye motion. The numerical part of our solution is an algorithm that enables proper coding of wide-angle holographic information for projecting correct object reconstruction at arbitrary eye position within the extended eyebox. The algorithm is developed through the employment of the phase-space representation, which facilitates the analysis of the holographic information and the impact of the diffraction grating in the wide-angle display system. It is shown that accurate encoding of the wavefront information components for the eyebox replicas is possible. In this way, the problem of missing or incorrect views in wide angle near-eye display with multiplied eyeboxes is efficiently solved. Moreover, this study investigates the space-frequency relation between the object and the eyebox and how the hologram information is shared between eyebox replicas. The functionality of our solution is tested experimentally in an augmented reality holographic near-eye display that has maximum field of view of 25.89°. Obtained optical reconstructions demonstrate that correct object view is obtained for arbitrary eye position within extended eyebox.

Recent Applications of Optical Elements in Augmented and Virtual Reality Displays: A Review

“…While the main focus is on the NEDs with their FoV and EB enhancement, VAC mitigation, and form factor reduction, other types of the AR/VR displays including the floating displays and head-up displays (HUDs) are also discussed in this paper. In the following sections, we introduce novel AR/VR displays using various optical elements including the photopolymer (PP)-based holographic optical element (HOE), liquid crystal (LC)-based HOE, geometric phase (GP) element, and metasurface, except the surface relief grating (SRG). ,− The geometric optic-based elements such as partial and polarizing mirror, retroreflector, focus-tunable component are also covered. Finally, we discuss the combination of those optical elements for further enhancement of the AR/VR display performance.…”