Waveguide display with cross-polarized eye pupil expanders

Patent metadata

Field	Value
Publication number	US-12306405-B2
Application number	US-202117916498-A
Country	US
Kind code	B2
Filing date	Apr 1, 2021
Priority date	Apr 6, 2020
Publication date	May 20, 2025
Grant date	May 20, 2025

Abstract

Embodiments include an optical system that may be included in a waveguide display. An example apparatus includes an image generator configured to generate an image having an upper portion and a lower portion. A waveguide is provided with an in-coupler and an out-coupler, the in-coupler being arranged to couple the upper and lower portions of the image along an optical path to the out-coupler. Along the optical path, at least first and second polarization-selective diffraction gratings are configured to cooperatively direct the upper portion of the image toward the out-coupler. At least third and fourth polarization-selective diffraction gratings are configured to cooperatively direct the lower portion of the image toward the out-coupler.

First claim

What is claimed:

1. An apparatus comprising:
an image generator configured to generate an image;
a waveguide having a first surface and a second surface opposite to the first surface, the waveguide having arranged on the first surface a single non-polarization-selective in-coupler, a first polarization-selective diffraction grating, a second polarization-selective diffraction grating, and a single non-polarization selective out-coupler, the waveguide having arranged on the second surface a third polarization-selective diffraction grating and a fourth polarization-selective diffraction grating;
the single non-polarization-selective in-coupler, the first polarization-selective diffraction grating, and the second polarization-selective diffraction grating operating as a first optical path for directing light from a first part of the image according to a first polarization state to a first area of the single non-polarization-selective out-coupler, and the single non-polarization-selective in-coupler, the third polarization-selective diffraction grating and the fourth polarization-selective diffraction grating operating as a second optical path for directing light from a second part of the image according to a second polarization state to a second area of the single non-polarization-selective out-coupler.

2. The apparatus of claim 1 , wherein:
the image generator is configured to generate an image having a left portion and a right portion, the left portion including an upper-left quadrant and a lower-left quadrant, the right portion including an upper-right quadrant and a lower-right quadrant;
wherein the single non-polarization-selective in-coupler is arranged to couple the left portion of the image along the first optical path and along the second optical path to the single non-polarization-selective out-coupler and to couple the right portion of the image along a third optical path and along a fourth optical path to the single non-polarization-selective out-coupler;
wherein the first and second polarization-selective diffraction gratings are configured to cooperatively direct the upper-left quadrant toward the single non-polarization-selective out-coupler, and the third and fourth polarization-selective diffraction gratings are configured to cooperatively direct the lower-left quadrant toward the single non-polarization-selective out-coupler;
the apparatus further comprising:
a fifth polarization-selective diffraction grating and a sixth polarization-selective diffraction grating along the third optical path, wherein the fifth and sixth polarization-selective diffraction gratings have a greater diffraction efficiency for light having the first polarization state than for light having the second polarization state, the fifth and sixth polarization-selective diffraction gratings being configured to cooperatively direct the upper-right quadrant toward the single non-polarization-selective out-coupler; and
a seventh polarization-selective diffraction grating and an eighth polarization-selective diffraction grating along the fourth optical path, wherein the seventh and eighth polarization-selective diffraction gratings have a greater diffraction efficiency for light having the second polarization state than for light having the first polarization state, the seventh and eighth polarization-selective diffraction gratings being configured to cooperatively direct the lower-right quadrant toward the single non-polarization-selective out-coupler.

3. The apparatus of claim 1 , wherein the first polarization state is one of p-polarization and s-polarization and the second polarization state is the other of p-polarization and s-polarization.

4. The apparatus of claim 1 , wherein the first and third diffraction gratings are arranged in at least partially overlapping positions on opposite surfaces of the waveguide.

5. The apparatus of claim 1 , wherein the second and fourth diffraction gratings are arranged in at least partially overlapping positions on opposite surfaces of the waveguide.

6. The apparatus of claim 1 , wherein the first and second diffraction gratings have a first grating period and the third and fourth diffraction gratings have a second grating period different from the first grating period.

7. The apparatus of claim 1 , wherein the image generator is operative to generate an image with unpolarized light.

8. A method comprising:
generating an image;
coupling the image into a waveguide using a single non-polarization-selective in-coupler of the waveguide;
directing a first portion of the image along a first optical path from the single non-polarization-selective in-coupler to a single non-polarization-selective out-coupler of the waveguide using at least a first and a second polarization-selective diffraction grating, wherein the first and second polarization-selective diffraction gratings have a greater diffraction efficiency for light having a first polarization state than for light having a second polarization state complementary to the first polarization state; and
directing a second portion of the image along the first optical path from the single non-polarization-selective in-coupler to the single non-polarization-selective out-coupler using at least a third and a fourth polarization-selective diffraction grating, wherein the third and fourth polarization-selective diffraction gratings have a greater diffraction efficiency for light having the second polarization state than for light having the first polarization state.

9. The method of claim 8 , wherein the first portion of the image is an upper portion of the image and the second portion of the image is a lower portion of the image.

10. The method of claim 8 , further comprising:
directing a third portion of the image along a third optical path from the single non-polarization-selective in-coupler to the single non-polarization-selective out-coupler using at least a fifth and a sixth polarization-selective diffraction grating, wherein the fifth and sixth polarization-selective diffraction gratings have a greater diffraction efficiency for light having the first polarization state than for light having the second polarization state; and
directing a fourth portion of the image along a fourth optical path from the single non-polarization-selective in-coupler to the single non-polarization-selective out-coupler of the waveguide using at least a seventh and an eighth polarization-selective diffraction grating, wherein the seventh and eighth polarization-selective diffraction gratings have a greater diffraction efficiency for light having the second polarization state than for light having the first polarization state.

11. The method of claim 8 , wherein the first polarization state is one of p-polarization and s-polarization and the second polarization state is the other of p-polarization and s-polarization.

12. The method of claim 8 , wherein the first and third polarization-selective diffraction gratings are arranged in at least partially overlapping positions on opposite surfaces of the waveguide.

13. The method of claim 8 , wherein the first and second polarization-selective diffraction gratings have a first grating period and the third and fourth polarization-selective diffraction gratings have a second grating period different from the first grating period.

14. The method of claim 8 , wherein the image is generated with unpolarized light.

Assignees

• Interdigital Ce Patent Holdings Sas

Inventors

• Drazic Valter
• Shramkova Oksana

Classifications

• G02B2027/0123

  comprising devices increasing the field of view · CPC title

• G02B6/0056

  for producing polarisation effects, e.g. by a surface with polarizing properties or by an additional polarizing elements · CPC title

• G02B6/0036

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

• G02B27/1086

  operating by diffraction only · CPC title

• G02B27/283

  used for beam splitting or combining · CPC title