A waveguide image combiner is used to transmit a monochrome or full-color image in an augmented reality display. The combiner uses multiple pairs of overlapping incoupling and outcoupling VHOEs to expand the horizontal FOV and a Y expander to expand the vertical FOV. This suitably provides an expanded horizontal and vertical FOV that offers a diagonal FOV≥50°, a horizontal FOV≥40 and a vertical FOV≥25°. The combiner also delivers a large horizontal eye box up to 20 mm and a vertical eye box of 10 mm while maintaining high light efficiency of the real scene (e.g. >80%). The system is able to use a light engine based on broadband (10 nm≤Δλ≤30 nm) LEDs and maintain a large horizontal field of view and high transmission of the real imagery. The approach resolves issues with current embodiments including astigmatism, image overlap, color balance, and small light engine pupils leading to reduced eye boxes.
Waveguide image combiner for augmented reality displays