Multilayer waveguide structures can realize full-color AR displays of diffractive waveguides. This paper discusses the field-of-view characteristics of a waveguide system with a multilayer structure when polarization volume gratings (PVG) are applied as couplers to achieve a full-color display. The effects of the refractive index and period parameter of PVG-couplers on the field of view are investigated. In addition, a PVG waveguide sample with an optimized design is prepared. The experimental results show that the designed waveguide system can achieve a full-color AR display with a 45° diagonal field of view, which verifies the feasibility of the design and provides a potential solution for AR color waveguide display applications.
In augmented reality diffractive waveguide technology, the light field needs to be collimated before being transmitted into the diffractive waveguide. Conventional schemes usually require additional collimating optics to collimate the light from the micro-image source and guide it into the waveguide in-coupling elements. In order to meet the needs of head-mounted devices and further miniaturize the equipment, this paper proposes a waveguide device that combines collimation and coupling by using a reflective polarization volume lens (PVL). A related model is also established and simulated to calculate the diffraction and transmission characteristics of the PVL element, and is then improved to fit the experiment. The diffraction lens studied in this paper has high diffraction efficiency with a large off-axis angle, which can fold the optical path and reduce considerably the volume of the optical system when applied to the waveguide system.