Optical combiner with uniform illuminance throughput

Patent metadata

Field	Value
Publication number	US-12204136-B2
Application number	US-202217901851-A
Country	US
Kind code	B2
Filing date	Sep 2, 2022
Priority date	Oct 29, 2019
Publication date	Jan 21, 2025
Grant date	Jan 21, 2025

Abstract

A device includes a display configured to generate an image light. The device also includes a waveguide optically coupled with the display and configured to guide the image light to an exit pupil of the device. The waveguide includes a grating including a birefringent material, and a birefringence of the grating is configured to increase along a pupil-expanding direction of the device.

First claim

What is claimed is:

1. A device, comprising:
a display configured to generate an image light; and
a waveguide optically coupled with the display and configured to guide the image light to an exit pupil of the device,
wherein the waveguide comprises a grating including a birefringent material, and a birefringence of the grating is configured to increase along a pupil-expanding direction of the device.

2. The device of claim 1 , wherein a projection of a grating vector of the grating on a plane perpendicular to a thickness direction of the grating is configured to be parallel with the pupil-expanding direction.

3. The device of claim 1 , wherein the grating includes a transmissive polarization volume hologram.

4. The device of claim 1 , wherein the grating includes a reflective polarization volume hologram.

5. The device of claim 1 , wherein a thickness of the grating is configured to vary along the pupil-expanding direction.

6. The device of claim 5 , wherein the thickness of the grating is configured to increase along the pupil-expanding direction.

7. The device of claim 1 , wherein a diffraction efficiency of the grating is configured to increase along the pupil-expanding direction.

8. A device, comprising:
a display configured to generate a first image light; and
a waveguide optically coupled with the display and comprising:
an in-coupling element configured to couple the first image light into the waveguide as a second image light that propagates inside the waveguide via total internal reflection; and
an out-coupling element configured with a predetermined diffraction efficiency gradient along a pupil-expansion direction of the device,
wherein as the second image light propagates inside the waveguide via total internal reflection, the out-coupling element is configured to diffract, in the predetermined diffraction efficiency gradient, the second image light incident onto a plurality of portions of the out-coupling element with the same incidence angle out of the waveguide as a plurality of parallel third image lights,
wherein the out-coupling element includes a birefringent material, and is configured with a predetermined birefringence gradient along the pupil-expansion direction.

9. The device of claim 8 , wherein the predetermined diffraction efficiency gradient is configured to increase along the pupil-expansion direction.

10. The device of claim 8 , wherein the predetermined birefringence gradient is configured to increase along the pupil-expansion direction.

11. The device of claim 8 , wherein the out-coupling element includes a birefringent material, and is configured with a predetermined thickness gradient along the pupil-expansion direction.

12. The device of claim 8 , wherein the out-coupling element includes a transmissive polarization volume hologram.

13. The device of claim 8 , wherein the out-coupling element includes a reflective polarization volume hologram.

14. A device, comprising:
a display configured to generate a first image light; and
a waveguide optically coupled with the display and comprising:
an in-coupling element configured to couple the first image light into the waveguide as a second image light that propagates inside the waveguide via total internal reflection; and
an out-coupling element configured with a predetermined diffraction efficiency gradient along a pupil-expansion direction of the device,
wherein as the second image light propagates inside the waveguide via total internal reflection, the out-coupling element is configured to diffract, in the predetermined diffraction efficiency gradient, the second image light incident onto a plurality of portions of the out-coupling element with the same incidence angle out of the waveguide as a plurality of parallel third image lights,
wherein the out-coupling element includes a birefringent material, and is configured with a predetermined thickness gradient along the pupil-expansion direction, and
wherein the predetermined thickness gradient is configured to increase along the pupil-expansion direction.

15. The device of claim 14 , wherein the out-coupling element includes a transmissive polarization volume hologram.

16. The device of claim 14 , wherein the out-coupling element includes a reflective polarization volume hologram.

Assignees

• Meta Platforms Tech Llc

Inventors

• Lee Yun-Han
• Lu Lu
• Wang Mengfei
• Peng Fenglin
• Wang Junren
• Yaroshchuk Oleg
• Jiang Yingfei
• Amirsolaimani Babak
• McEldowney Scott Charles

Classifications

• G02B27/0172

  characterised by optical features · CPC title

• G02B2027/0174

  holographic · CPC title

• G03H2260/12

  Photopolymer · CPC title

• G02B2027/0178

  Eyeglass type (eyeglass details G02C) · CPC title

• G03H1/0248 Primary

  Volume holograms · CPC title