US Patent 11789265 Waveguide image combiners for augmented reality displays

A waveguide image combiner is used to transmit a monochrome or full-color image in an augmented reality display. The combiner uses multiple stacked waveguides, each having top and bottom substrates. The combiner also uses multiple pairs of incoupling and outcoupling VHOEs, which are sandwiched between the top and bottom substrates, to expand a first FOV and an image expander to expand the second or perpendicular FOV. This suitably provides an expanded 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≤40 nm) LEDs and maintain a large horizontal field of view and high transmission of the real imagery.