Foveated near-eye display for mixed reality using liquid crystal photonics

Abstract

Foveated near-eye display is one of the most promising approaches to deliver immersive experience of mixed reality. However, it is challenged to conceive a compact optical system. Here, we introduce a method to use polarization optics via liquid crystal photonics to improve the foveated display performance. We demonstrate a benchtop prototype of this idea. We implement and combine two display modules for peripheral and foveal visions. A peripheral display consists of a polarization selective lens (PSL) module, a polarization selective diffuser (PSD), and a slanted projection system. An 80$$^\circ$$ ∘ diagonal field of view is achieved by on-axis optical configuration of the PSL module and the PSD. A foveal holographic display is composed of a spatial light modulator (SLM), a volume grating lens, and a microelectromechanical system mirror possibly in combination with a switchable polarization selective grating module. The holographic reconstruction using the SLM enables accurate focus cue generation and high resolution above 30 cycles per degree within 15$$^\circ$$ ∘ by 15$$^\circ$$ ∘ field of view. We explore and discuss the liquid crystal photonics in the prototype that has a novel optical design using volume gratings with polarization selectivity.

Augmented reality and virtual reality displays: emerging technologies and future perspectives

“…To circumvent this issue, the concept of the foveated display is proposed [9][10][11][12][13] . The idea is based on that the human eye only has high visual acuity in the central fovea region, which accounts for about 10°FoV.…”

“…If the highresolution image is only projected to fovea while the peripheral image remains low resolution, then a microdisplay with 2K resolution can satisfy the need. Regarding the implementation method of foveated display, a straightforward way is to optically combine two display sources [9][10][11] : one for foveal and one for peripheral FoV. This approach can be regarded as spatial multiplexing of displays.…”

33‐1: Invited Paper: Liquid Crystals for Virtual Reality (VR)

“…Finally, a polarization diffuser (Fig. 1(e)) [5] can be fabricated by introducing a pseudo-random surface patterning. With chiral dopant added, such cholesteric diffusers can also be a "polarization Bragg diffuser" where only selective wavelength and polarization is diffused.…”

Foveated imaging by polarization multiplexing for compact near‐eye displays

“…Therefore, foveated imaging becomes a more favorable solution to provide ultra-high-resolution images by considering the panel fabrication and data transport difficulties. [7][8][9][10][11][12] Due to the 1-arcmin requirement being only for the narrow central region (< ±5 ) defined by the cone cell distribution on retina, we may only need to provide high resolution for central fovea region instead of the entire field of view. 13 To achieve foveated VR display, current approaches employ two separate display panels to provide low-resolution and high-resolution images, respectively.…”