Full‐color, wide field‐of‐view single‐layer waveguide for augmented reality displays

• Published in: Journal of the Society for Information Display 2024-05, Vol.32 (5), p.247-254
• Main Authors: Yang, Qian, Ding, Yuqiang, Wu, Shin‐Tson
• Format: Article
• Language: English
• Subjects: Aspect ratio; Augmented reality; Color; Displays; exit pupil expansion; liquid crystal polarization volume grating; Refractivity; waveguide display; Waveguides
• ISSN: 1071-0922; 1938-3657
• DOI: 10.1002/jsid.1288

In the quest for more compact and efficient augmented reality (AR) displays, the standard approach often necessitates the use of multiple layers to facilitate a large full‐color field of view (FoV). Here, we delve into the constraints of FoV in single‐layer, full‐color waveguide‐based AR displays, uncovering the critical roles played by the waveguide's refractive index, the exit pupil expansion (EPE) scheme, and the combiner's angular response in dictating these limitations. Through detailed analysis, we introduce an innovative approach, featuring an optimized butterfly EPE scheme coupled with gradient‐pitch polarization volume gratings (PVGs). This novel configuration successfully achieves a theoretical diagonal FoV of 54.06° while maintaining a 16:10 aspect ratio. We analyze the field‐of‐view (FoV) limitations in a single‐layer, full‐color waveguide‐based augmented reality display, revealing key influences from the waveguide's refractive index, exit pupil expansion (EPE) scheme, and combiner's angular response. Based on these analyses, we propose an optimized butterfly EPE scheme with gradient‐pitch polarization volume gratings, achieving a theoretical diagonal FoV of 54.06° with a 16:10 aspect ratio.