Methods and systems for generating virtual content display with a virtual or augmented reality apparatus
Several unique configurations for interferometric recording of volumetric phase diffractive elements with relatively high angle diffraction for use in waveguides are disclosed. Separate layer EPE and OPE structures produced by various methods may be integrated in side-by-side or overlaid constructs, and multiple such EPE and OPE structures may be combined or multiplexed to exhibit EPE/OPE functionality in a single, spatially-coincident layer. Multiplexed structures reduce the total number of layers of materials within a stack of eyepiece optics, each of which may be responsible for displaying a given focal depth range of a volumetric image. Volumetric phase type diffractive elements are used to offer properties including spectral bandwidth selectivity that may enable registered multi-color diffracted fields, angular multiplexing capability to facilitate tiling and field-of-view expansion without crosstalk, and all-optical, relatively simple prototyping compared to other diffractive element forms, enabling rapid design iteration.
1. An apparatus for generating stereoscopic images for virtual reality and/or augmented reality, comprising:
an in-coupling optical device to receive input light beams;
a single film or layer that is to be folded;
first diffractive elements in the apparatus to propagate and deflect a propagation direction of a first portion of the input light beams from the in-coupling optical device into a first direction toward second diffractive elements, the first diffractive elements fabricated on the single film or layer and having a first orientation; and
an eyepiece comprising a transmissive substrate to propagate a second portion of the input light beams through the second diffractive elements fabricated on the single film or layer and having a second orientation different from the first orientation to produce stereoscopic images on one or more focal planes to an observer,
wherein the single film or layer comprising the first diffractive elements and the second diffractive elements is arranged in a folded configuration over the transmissive substrate to be integrated with the transmissive substrate, position the first diffractive elements and the second diffractive elements of the single film or layer in the folded configuration on opposite sides of the transmissive substrate, and allow, by the folded configuration, respective input light beam portions to propagate through the first diffractive elements, the transmissive substrate and the second diffractive elements to the observer.
2. The apparatus of claim 1 , wherein the second diffractive elements comprise exit pupil expansion structures or expanders, and the first diffractive elements comprise orthogonal pupil expansion structures or expanders.
3. The apparatus of claim 1 , wherein at least one of the first diffractive elements and the second diffractive elements includes a host medium that comprises a dry-process photopolymer material.
4. The apparatus of claim 3 , wherein the host medium includes a single-layer photopolymer material, single-layer silver halides, or single-layer polymer-dispersed liquid crystal mixture material.
5. The apparatus of claim 1 , wherein the eyepiece is to guide propagation of the input light beams by at least successively redirecting first light wave-fronts of at least the first portion of the input light beams and out-coupling with at least the second portion of the input light beams via total internal reflection.
6. The apparatus of claim 1 , wherein at least one of the first diffractive elements and the second diffractive elements is a volumetric-phase type diffractive element.
7. The apparatus of claim 6 , wherein the first diffractive elements and the second diffractive elements are volumetric-phase type diffractive elements that are identified or fabricated without using surface-relief structures.
8. The apparatus of claim 1 , further comprising:
switchable diffractive elements for the first diffractive elements and/or the second diffractive elements; and
a time-multiplexed distribution mechanism to provide time-multiplexed distribution of projected images to one or more focal planes by using the switchable diffractive elements for the first diffractive elements and/or the second diffractive elements.
9. The apparatus of claim 1 , wherein at least one of the first diffractive elements and the second diffractive elements includes polymer-dispersed liquid crystal (PDLC) components.
10. The apparatus of claim 9 , further comprising:
a host medium for the PDLC components;
structural elements in the host medium of the PDLC components; and
a refraction index determination mechanism to determine a refraction index of the host medium or the structural elements to be an index that does not match a first refraction index of the transmissive substrate on which the first diffractive elements and/or the second diffractive elements are disposed.
11. The apparatus of claim 1 , wherein the single film or layer comprises a multiplexed arrangement of the first diffractive elements and the second diffractive elements to reduce crosstalk in diffraction of propagation of the input light beams in at least a portion of the eyepiece.
12. The apparatus of claim 1 , wherein the first diffractive elements and the second diffractive elements include a combination of volumetric phase diffractive elements and surface relief structures.
13. The apparatus of claim 1 , wherein the transmissive substrate comprises two or more layers of translucent or transparent host media that are coupled with each other to jointly form a waveguide for at least a portion of the input light beams to produce the stereoscopic images.