Planar waveguide apparatus with diffraction element(s) and system employing same
View Patent ↗A waveguide apparatus includes a planar waveguide and at least one optical diffraction element (DOE) that provides a plurality of optical paths between an exterior and interior of the planar waveguide. A phase profile of the DOE may combine a linear diffraction grating with a circular lens, to shape a wave front and produce beams with desired focus. Waveguide apparati may be assembled to create multiple focal planes. The DOE may have a low diffraction efficiency, and planar waveguides may be transparent when viewed normally, allowing passage of light from an ambient environment (e.g., real world) useful in AR systems. Light may be returned for temporally sequentially passes through the planar waveguide. The DOE(s) may be fixed or may have dynamically adjustable characteristics. An optical coupler system may couple images to the waveguide apparatus from a projector, for instance a biaxially scanning cantilevered optical fiber tip.
1. A waveguide array apparatus, comprising:
a plurality of planar waveguides, including
a first planar waveguide of the plurality having a first end, a second end, a first face, and a second face, the first end of the first planar waveguide opposed to the second end of the first planar waveguide along a length of the first planar waveguide, at least the first and the second faces of the first planar waveguide forming a first at least partially internally reflective optical path along at least a portion of the length of the first planar waveguide, and
a second planar waveguide of the plurality having a first end, a second end, a first face, and a second face, the first end of the second planar waveguide opposed to the second end of the second planar waveguide along a length of the second planar waveguide, at least the first and the second faces of the second planar waveguide forming a second at least partially internally reflective optical path along at least a portion of the length of the second planar waveguide,
wherein the second face of the first planar waveguide is disposed adjacent to the first face of the second planar waveguide;
a first reflector disposed adjacent respective first ends of the first and second planar waveguides; and
a second reflector disposed adjacent respective second ends of the first and second planar waveguides,
wherein each of the first and second planar waveguides has a respective diffractive optical element[s] disposed between the respective first and second ends at respective positions along at least a portion of the length of the respective first and second planar waveguides to reflect a respective portion of a respective spherical wave front outwardly from the first face of the respective first and second planar waveguides.
2. The waveguide array apparatus of claim 1 , wherein at least one of the respective diffractive optical elements is integral with a respective planar waveguide[s].
3. The waveguide array apparatus of claim 1 , wherein at least one of the respective diffractive optical elements is disposed between the first and second faces of a respective planar waveguide.
4. The waveguide array apparatus of claim 1 , wherein at least one of the respective diffractive optical elements is disposed at one of the first face or second faces of a respective planar waveguide.
5. The waveguide array apparatus of claim 1 , wherein at least one of the respective diffractive optical elements is a Bragg grating.
6. The waveguide array apparatus of claim 1 , wherein at least one of the respective diffractive optical elements combines a linear diffraction function and a radially circular lens function.
7. The waveguide array apparatus of claim 1 , wherein at least one of the respective diffractive optical elements has a phase profile that is a combination of a linear diffraction grating and a radially symmetric lens.