Waveguide image combiners for augmented reality displays

A waveguide image combiner for combining light from real imagery with light from a light engine, said waveguide image combiner comprising:

• a. a first optically transparent substrate having top and bottom surfaces;
• b. a first pair of couplers comprising a first incoupler and a first outcoupler that are spaced apart and overlaid on the top surface of the first optically transparent substrate;
• c. a second optically transparent substrate having top and bottom surfaces,
• stacked with the first optically transparent substrate such that the top and bottom surfaces of the two substrates are substantially parallel;
• and
• d. a second pair of couplers comprising a second incoupler and a second outcoupler that are spaced apart and overlaid on the top surface of the second optically transparent substrate;
• wherein each coupler comprises one or more volume holographic optical elements (VHOEs), wherein each VHOE comprises one or more gratings, wherein each of the gratings corresponds to a color range and an angular range, wherein each coupler comprises gratings corresponding to different angular ranges, wherein the first outcoupler is configured for a first light transmission according to a first output angular range and a second output angular range, and wherein the second outcoupler is configured for a second light transmission according to the second output angular range.

A method of producing a waveguide image combiner, the method comprising:

• a. defining a total angular output range along a first axis, which is segmented into a plurality of adjacent angular output ranges;
• b. providing a plurality of optically transparent substrates having top and bottom surfaces, the substrates aligned and stacked with each other such that the top and bottom surfaces of the substrates are substantially parallel, wherein each substrate comprises a pair of couplers, comprising an overlaid incoupler and an overlaid outcoupler, spaced apart on the top surface of the substrate, wherein each coupler comprises one or more volume holographic optical elements (VHOEs) and each of the VHOEs comprise one or more gratings, wherein each grating corresponds to a color range, wherein a first outcoupler of a first pair of couplers is configured for a first light transmission according to a first output angular range and a second output angular range, and wherein a second outcoupler of a second pair of couplers is configured for a second light transmission according to the second output angular range;
• and
• c. recording a holographic pattern which corresponds to an angular output range on each grating such that no two gratings within a coupler which have the same angular range correspond to neighboring color ranges in the electromagnetic spectrum.