Method and system for dual projector waveguide displays with wide field of view
A method of operating an eyepiece waveguide having a first region and a second region includes directing light from a first projector to impinge on a first incoupling grating (ICG) and light from a second projector to impinge on a second ICG. Light from the first projector is diffracted into a first portion and a second portion of the first region of the eyepiece waveguide and out of the eyepiece waveguide. Light from the second projector is diffracted into a first portion and a second portion of the second region of the eyepiece waveguide and out of the eyepiece waveguide.
1. A method of operating an eyepiece waveguide having a first region and a second region, the method comprising:
directing light from a first projector to impinge on a first incoupling grating (ICG);
diffracting a fraction of the light from the first projector into a first portion of the first region of the eyepiece waveguide, into a first portion of the second region, into a second portion of the second region, and out of the eyepiece waveguide;
diffracting another fraction of the light from the first projector into a second portion of the first region of the eyepiece waveguide, into a second portion of the second region, into the first portion of the second region, and out of the eyepiece waveguide;
directing light from a second projector to impinge on a second ICG;
diffracting a fraction of the light from the second projector into the first portion of the second region of the eyepiece waveguide, into the first portion of the first region, into the second portion of the first region, and out of the eyepiece waveguide; and
diffracting another fraction of the light from the second projector into the second portion of the second region of the eyepiece waveguide, into the second portion of the first region, into the first portion of the first region, and out of the eyepiece waveguide.
2. The method of claim 1 wherein:
the first region includes:
a first set of diffractive optical elements disposed in the first portion of the first region and oriented at a positive angle with respect to an axis; and
a second set of diffractive optical elements disposed in the second portion of the first region and oriented at a negative angle with respect to the axis; and
the second region includes:
a third set of diffractive optical elements disposed in the first portion of the second region and oriented at 180° plus the negative angle with respect to the axis; and
a fourth set of diffractive optical elements disposed in the second portion of the second region and oriented at 180° minus the positive angle with respect to the axis.
3. The method of claim 2 wherein the first set of diffractive optical elements comprises a first set of gratings and the second set of diffractive optical elements comprises a second set of gratings, wherein the first set of gratings and the second set of gratings are blazed and characterized by decreased outcoupling efficiency for light from the first projector.
4. The method of claim 2 wherein the third set of diffractive optical elements comprises a third set of gratings and the fourth set of diffractive optical elements comprises a fourth set of gratings, wherein the third set of gratings and the fourth set of gratings are blazed and characterized by decreased outcoupling efficiency for light from the second projector.
5. The method of claim 2 wherein the positive angle is ˜30° and the negative angle is ˜−30°.
6. The method of claim 1 wherein the first region and the second region form an overlap region.
7. The method of claim 6 wherein the overlap region is disposed at a midpoint between the first ICG and the second ICG.
8. The method of claim 1 wherein:
the light from the first projector impinges on the first ICG at a first non-zero angle of incidence; and
the light from the second projector impinges on the second ICG at a second non-zero angle of incidence equal to zero minus the first non-zero angle of incidence.
9. The method of claim 8 wherein:
a first field of view of the first portion of the second region is centered at the first non-zero angle of incidence; and
a second field of view of the first portion of the first region is centered at the second non-zero angle of incidence.
10. The method of claim 1 wherein:
the eyepiece waveguide has a first surface and a second surface opposing the first surface; and
the first ICG is formed on or in the first surface or the second surface.
11. The method of claim 1 wherein:
the eyepiece waveguide has a first surface and a second surface opposing the first surface; and
the second ICG is formed on or in the first surface or the second surface.
12. The method of claim 1 further comprising forming a first field of view using light from the first projector that is diffracted out of the eyepiece waveguide.
13. The method of claim 12 further comprising forming a second field of view using light from the second projector that is diffracted out of the eyepiece waveguide.
14. The method of claim 13 wherein:
the first field of view is centered at a non-normal angle of incidence; and
the second field of view is centered at zero minus the non-normal angle of incidence.
15. The method of claim 13 wherein the first field of view and the second field of view form a combined field of view.
16. The method of claim 13 wherein the first field of view and the second field of view are tiled.
17. The method of claim 13 wherein a portion of the first field of view overlaps with a portion of the second field of view.