Waveguide with a beam splitter upstream of output region

Patent metadata

Field	Value
Publication number	US-12468148-B2
Application number	US-202117519391-A
Country	US
Kind code	B2
Filing date	Nov 4, 2021
Priority date	Nov 4, 2021
Publication date	Nov 11, 2025
Grant date	Nov 11, 2025

Abstract

A waveguide, e.g. a pupil-replicating waveguide, is provided. The waveguide includes a substrate having two outer surfaces, for propagating a beam of light in the substrate by reflecting the beam from the outer surfaces. An output coupler, such as a diffraction grating in the substrate, is configured for diffracting the impinging beam out of the substrate. A beam splitter is disposed in the substrate between the outer surfaces upstream of the output coupler, so as to avoid substantially intersecting the output beam. The partial reflector is configured for splitting the impinging beam, increasing the number of beam portions in the waveguide, thereby improving output pupil density.

First claim

What is claimed is:

1 . A display apparatus comprising:
a light source for emitting a beam of light; a display panel disposed to receive at least a portion of output light and to provide image light; a projection lens disposed to receive the image light from the display panel; and a pupil-replicating waveguide comprising a substrate, the substrate comprising:
an input region configured to couple, into the substrate, the beam received in an input pupil;
an output region at a distance from the input region comprising an output coupler configured to out-couple at least a portion of the beam out of the substrate as output light;
two opposing outer surfaces for guiding the beam in the substrate by reflections therefrom; and
a beam splitter disposed in an optical path of the beam between the input region and output region and configured to split the beam into beam portions propagating toward the two opposing outer surfaces,
wherein the pupil-replicating waveguide is disposed in part between the projection lens and the display panel, and wherein the beam splitter is disposed not to intersect the image light propagating from the display panel to the projection lens.

2 . The display apparatus of claim 1 , wherein the output coupler comprises an output diffraction grating configured to diffract at least a portion of the beam into an eyebox outside of the pupil-replicating waveguide, and wherein the beam splitter is disposed away from an optical path of the light diffracted by the output diffraction grating into the eyebox.

3 . The display apparatus of claim 1 , wherein the input region includes an input coupler configured to couple the beam of light into the substrate.

4 . The display apparatus of claim 3 , wherein the input coupler and the beam splitter overlap when viewed in a vertical direction normal to at least one of the two opposing outer surfaces.

5 . The display apparatus of claim 1 , wherein the beam splitter comprises a partially reflective layer extending parallel to, and between, the two opposing outer surfaces.

6 . A method for increasing optical pupil replication density, the method comprising:
using, in an optical pupil replicating waveguide, an input coupler to couple a beam of light into the optical pupil replicating waveguide; and using, in the optical pupil replicating waveguide, a beam splitter for splitting, upstream of an output coupler of the optical pupil replicating waveguide, a beam of light propagating in the optical pupil replicating waveguide into sub-beams propagating toward different ones of two opposing outer surfaces of the optical pupil replicating waveguide, and for re-directing the sub-beams out of the optical pupil replicating waveguide without impinging onto the beam splitter, wherein the optical pupil replicating waveguide is disposed in part between a projection lens and a display panel, and wherein the beam splitter is disposed not to intersect image light propagating from the display panel to the projection lens.

7 . The method of claim 6 , further comprising using a beam splitting layer extending between and along the two opposing outer surfaces away from an optical path of the beam to at least one of: an eye box of a near-eye display; or a pixel array of a panel display.

8 . The method of claim 6 , further comprising using a folding reflector for pupil replication along a first direction and using an output coupler for pupil replication along a second, different direction, and using the beam splitter for at least doubling a pupil replication density along at least one of the first direction and the second, different direction.

Assignees

• Meta Platforms Tech Llc

Inventors

• Amirsolaimani Babak
• He Sihui

Classifications

• G02B2027/0178

  Eyeglass type (eyeglass details G02C) · CPC title

• G02B27/0172 Primary

  characterised by optical features · CPC title

• G02B6/0036

  2-D arrangement of prisms, protrusions, indentations or roughened surfaces · CPC title

• G02B2027/0123

  comprising devices increasing the field of view · CPC title

• G02B27/0081

  with means for altering, e.g. enlarging, the entrance or exit pupil · CPC title