Flat metaform near-eye visor

TL;DR

This paper introduces a flat, metasurface-based near-eye visor that offers a wide field of view and high image quality, overcoming limitations of traditional freeform optics and waveguides in head-mounted displays.

Contribution

It presents a novel flat metasurface visor design that uses diffraction to achieve a large field of view and high image quality in near-eye displays.

Findings

Achieves 77.3° field of view horizontally and vertically.

Maintains high image quality suitable for human vision.

Validated design through both ray optics and full-wave simulations.

Abstract

A near-eye visor is one of the most vital components in a head-mounted display. Currently, freeform optics and waveguides are used to design near-eye visors, but these structures are complex and their field of view is limited when the visor is placed near the eye. In this paper, we propose a flat, freeform near-eye visor which uses a sub-wavelength patterned metasurface reflector. The visor design imparts a spatial phase profile on a projected display pattern and can be implemented using a micron-scale thick metasurface. As the resulting metaform visor relies on diffraction, it can preserve a large field of view (77.3{\deg} both horizontally and vertically) when placed only 2.5 cm away from the eye. We simulate the metasurface visor to estimate the modulation transfer function, and find that the projected image quality is sufficiently high for human vision. While the design of the metasurface is initially performed via ray optics, using full-wave finite-difference time-domain simulation we validate a scaled version of our visor design.