Very high index eyepiece substrate-based viewing optics assembly architectures
Very high refractive index (n>2.2) lightguide substrates enable the production of 70° field of view eyepieces with all three color primaries in a single eyepiece layer. Disclosed herein are viewing optics assembly architectures that make use of such eyepieces to reduce size and cost, simplifying manufacturing and assembly, and better-accommodating novel microdisplay designs.
1 . A method of manufacturing a diffractive optical element, the method comprising:
providing a substrate comprising a material that is transparent to visible light;
disposing a patternable layer over a surface of the substrate;
patterning the patternable layer to form a pattern comprising a plurality of features; and
etching the surface of the substrate through the patternable layer to fabricate structures on the surface of the substrate, wherein the structures comprise optical features configured to diffract visible light, wherein the optical features are positioned on waveguides at an intersection between a major surface and a subpupil, each waveguide of the waveguides being associated with a respective depth plane, being configured to direct a respective multiplexed light stream emitted by an image projection device to a viewer to produce an image appearing to originate from the respective depth plane, and wherein a refractive lens is positioned between a first waveguide and a second waveguide of the waveguides.
2 . The method of claim 1 , wherein the material has a refractive index greater than 1.79.
3 . The method of claim 1 , wherein the material comprises lithium niobate.
4 . The method of claim 1 , wherein disposing the patternable layer over the surface of the substrate comprises jet depositing the patternable layer over the surface of the substrate.
5 . The method of claim 1 , wherein the surface of the substrate is discharged prior to disposing the patternable layer.
6 . The method of claim 1 , wherein the patternable layer comprises a resin or a polymer and the patternable layer has a thickness between about 10 nm and about 1000 nm.
7 . The method of claim 1 , wherein the plurality of features is configured to diffract visible light into the substrate to be guided in the substrate or to diffract visible light guided within the substrate out of the substrate.
8 . A head mounted display device comprising:
a light projector comprising:
a light module;
a light modulator; and
a beam splitter,
wherein light from the light module is directed to and modified by the light modulator via the beam splitter, and the light projector generates a first multiplexed light stream comprising image information associated with a first depth plane and a second multiplexed light stream comprising image information associated with a second depth plane;
an eyepiece comprising:
a plurality of waveguides; and
a refractive lens between a first waveguide of the plurality of waveguides and a second waveguide of the plurality of waveguides,
wherein each waveguide of the plurality of waveguides comprises:
a material having a refractive index greater than 1.79;
a first in-coupling optical element disposed on a first major surface; and
a second in-coupling optical element disposed on a second major surface opposite the first major surface;
a plurality of optical features formed in at least one of the first major surface or the second major surface; and
input surfaces comprising a plurality of edges between the first major surface and the second major surface, being associated with a respective depth plane, and being configured to direct a respective multiplexed light stream emitted by the light projector to a viewer to produce an image appearing to originate from the respective depth plane,
wherein the light modulator changes a perceived intensity of the light injected into the plurality of waveguides.
9 . The head mounted display device of claim 8 , wherein the plurality of optical features are formed in at least one of the first major surface or the second major surface by etching at least one of the first major surface or the second major surface, respectively.
10 . The head mounted display device of claim 8 , wherein each waveguide of the plurality of waveguides comprises a material having a refractive index greater than or equal to 2.2.
11 . The head mounted display device of claim 8 , wherein each waveguide of the plurality of waveguides comprises lithium niobate.
12 . The head mounted display device of claim 8 , wherein each waveguide of the plurality of waveguides comprises silicon carbide.
13 . The head mounted display device of claim 8 , wherein at least some of the plurality of optical features are configured to incouple incident image light such that an incoupled image light propagates through each waveguide of the plurality of waveguides by a plurality of total internal reflections at the first major surface and the second major surface.
14 . The head mounted display device of claim 8 , further comprising a variable focus lens between each waveguide of the plurality of waveguides and a viewer, wherein the variable focus lens is configured to vary a focal plane of image light propagating through each waveguide of the plurality of waveguides by a plurality of total internal reflections and the first and the second major surface that is outcoupled from each waveguide of the plurality of waveguides towards the viewer.
15 . The head mounted display device of claim 14 , wherein the variable focus lens comprises a negative lens.
16 . The head mounted display device of claim 14 , wherein the variable focus lens comprises a liquid filled lens.
17 . The head mounted display device of claim 14 , wherein the variable focus lens comprises a liquid crystal.
18 . The head mounted display device of claim 8 , wherein the variable focus lens-comprises a switchable geometric phase lens-stack.
19 . The head mounted display device of claim 8 , wherein a waveguide of the plurality of waveguides is paired with a negative lens.
20 . The head mounted display device of claim 8 , further comprising a polarizer stacked with each waveguide of the plurality of waveguides.