Superimposed diffraction gratings for eyepieces

A waveguide comprising:

• a substrate;
• and
• an imprinted pattern on a side of the substrate, wherein the imprinted pattern comprises:
• a first zone comprising a first grating structure;
• a second zone comprising a second grating structure, wherein the first zone is between the substrate and the second zone, and wherein the second grating structure differs from the first grating structure;
• and
• a third zone comprising a third grating structure, wherein the second zone is between the first zone and the third zone, and wherein the third zone comprises a combined orthogonal pupil expander (OPE)/exit pupil expander (EPE) grating structure.

A waveguide comprising:

• a substrate;
• and
• an imprinted pattern on a side of the substrate, wherein the imprinted pattern comprises:
• a first zone comprising a first grating structure;
• a second zone comprising a second grating structure, wherein the first zone is between the substrate and the second zone, and wherein the second grating structure differs from the first grating structure;
• and
• a third zone comprising a third grating structure, wherein the second zone is between the first zone and the third zone, and wherein the first zone comprises a first material, the second zone comprises a second material, the third zone comprises a third material, and a refractive index of the second material exceeds a refractive index of the third material.