Polarization-based processing of unpolarized image light

Patent metadata

Field	Value
Publication number	US-12287484-B2
Application number	US-202318129620-A
Country	US
Kind code	B2
Filing date	Mar 31, 2023
Priority date	Sep 12, 2019
Publication date	Apr 29, 2025
Grant date	Apr 29, 2025

Abstract

A display system includes a source of unpolarized image light, and a stack of polarization-selective optical elements operable to switchably convert the unpolarized image light into two orthogonally polarized light beams, each of which being switchable in at least one beam characteristic. An output polarizer selects one of the two orthogonally polarized light beams for providing to a user. A depolarizer may be disposed between an electronic display emitting polarized light and the stack. The depolarizer may be in the form of an LC bilayer with randomized in-plane optic axis.

First claim

What is claimed is:

1. A method comprising:
propagating unpolarized image light through a sequence of polarization-selective optical elements of a display system to obtain two orthogonally polarized light beams, each of which being switchable in at least one beam characteristic, the at least one beam characteristic comprising at least one of:
a beam convergence characteristic; or
a beam deflection angle; and

using an optical polarizer disposed downstream of the sequence of polarization-selective optical elements to select one of the two orthogonally polarized light beams as an output light beam for forming an image; and
propagating polarized image light through a depolarizer to obtain the unpolarized image light for providing to the sequence of polarization-selective optical elements, the depolarizer comprising a liquid crystal (LC) bilayer with a randomized in-plane optic axis.

2. The method of claim 1 , wherein the propagating of the unpolarized image light comprises propagating the unpolarized image light through a sequence of Pancharatnam-Berry phase (PBP) lenses of differing nominal optical powers.

3. The method of claim 1 , wherein the propagating of the unpolarized image light comprises propagating the unpolarized image light through a sequence of polarization gratings.

4. The method of claim 1 , further comprising switching a polarization state of the orthogonally polarized light beams downstream of a polarization-selective optical element of the sequence of polarization-selective optical elements.

5. The method of claim 4 , wherein the switching is performed using a switchable half-wave plate (HWP).

6. The method of claim 1 , wherein the propagating of the unpolarized image light comprises propagating the unpolarized image light through a switchable Pancharatnam-Berry phase (PBP) lens, the method further comprising switching the switchable PBP lens to a state having substantially zero optical power.

7. The method of claim 1 , wherein the propagating of the unpolarized image light comprises propagating the unpolarized image light through a switchable PBP grating, the method further comprising switching the switchable PBP grating to a non-diffracting state.

8. The method of claim 1 , wherein the two orthogonally polarized light beams are orthogonally linearly polarized.

9. The method of claim 8 , wherein the optical polarizer comprises a linear polarizer.

Assignees

• Meta Platforms Tech Llc

Inventors

• Zhao Yang
• Jamali Afsoon
• Wang Junren
• Lam Wai Sze Tiffany
• Lu Lu
• Lanman Douglas Robert

Classifications

• G03B13/36

  Autofocus systems · CPC title

• G02F1/13718

  based on a change of the texture state of a cholesteric liquid crystal · CPC title

• G02B2027/0185

  Displaying image at variable distance · CPC title

• G02F1/1347

  Arrangement of liquid crystal layers or cells in which the final condition of one light beam is achieved by the addition of the effects of two or more layers or cells · CPC title

• G02B27/0172 Primary

  characterised by optical features · CPC title