Phase structure on volume Bragg grating-based waveguide display
AssigneeMeta Platforms Technologies, LLC
InventorsWai Sze Tiffany Lam, Yang Yang, Wanli Chi, Dominic Meiser
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Abstract
A waveguide display includes a substrate transparent to visible light, a first grating on the substrate and configured to couple display light into or out of the substrate, and a phase structure on the substrate and configured to change a polarization state of the display light after or before the display light reaches the first grating. The first grating is characterized by a polarization-dependent diffraction efficiency. The first grating includes, for example, a surface-relief grating or a volume Bragg grating.
Claims20
A waveguide display comprising:
- a first substrate transparent to visible light;
- a second substrate transparent to the visible light;
- a holographic material layer sandwiched by the first substrate and the second substrate and including a reflective volume Bragg grating characterized by a polarization-dependent diffraction efficiency, the reflective volume Bragg grating configured to more preferentially reflectively diffract incident light of a first polarization state over incident light of a second polarization state that is orthogonal to the first polarization state;
- and
- a phase structure on the first substrate or the second substrate and configured to change a polarization state of display light incident on the phase structure before the display light is diffracted by the reflective volume Bragg grating such that the display light incident on the reflective volume Bragg grating is predominantly in the first polarization state than the second polarization state with respect to the reflective volume Bragg grating to improve diffraction efficiency.
A waveguide display comprising:
- a first substrate;
- a second substrate;
- an input grating coupler between the first substrate and the second substrate and configured to couple display light into the first substrate or the second substrate via reflective diffraction that more preferentially reflectively diffracts incident light of a first polarization state over incident light of a second polarization state that is orthogonal to the first polarization state;
- an output grating coupler between the first substrate and the second substrate and configured to at least partially couple the display light out of the waveguide display towards an eyebox of the waveguide display via reflective diffraction that more preferentially reflectively diffracts incident light of the first polarization state over incident light of the second polarization state;
- and
- a phase structure on the first substrate or the second substrate and configured to change a polarization state of the display light coupled into the first substrate or the second substrate before the display light coupled into the first substrate or the second substrate reaches the output grating coupler such that the display light incident on the output grating coupler is predominantly in the first polarization state than the second polarization state with respect to the output grating coupler.
Dependencies are inferred from the claim text.