Optical waveguide structure, optical waveguide module and head-mounted display device

Patent metadata

Field	Value
Publication number	US-2025180908-A1
Application number	US-202418966742-A
Country	US
Kind code	A1
Filing date	Dec 3, 2024
Priority date	Dec 4, 2023
Publication date	Jun 5, 2025
Grant date	—

Abstract

The present application discloses an optical waveguide structure, an optical waveguide module and a head-mounted display device. The optical waveguide structure of the embodiments of the present application comprises a waveguide substrate, an in-coupling grating and a recovery grating. The in-coupling grating is configured to in-couple input light rays into the waveguide substrate to transmit the light rays. The diffraction grating is configured to perform pupil expansion on the light rays transmitted in the waveguide substrate and out-couple the light rays.

First claim

What is claimed is:

1 . An optical waveguide structure, comprising:
a waveguide substrate; an in-coupling grating configured to in-couple input light rays into the waveguide substrate to transmit the light rays; a diffraction grating configured to perform pupil expansion on the light rays transmitted in the waveguide substrate and out-couple the light rays; and a recovery grating configured to reflect the light rays which are not out-coupled and are transmitted to the recovery grating back to the diffraction grating, wherein the recovery grating is configured such that a wave vector space formed by at least portion of input light rays, after interacting with the in-coupling grating, the diffraction grating and the recovery grating, is closed.

2 . The optical waveguide structure according to claim 1 , wherein the in-coupling grating is configured to provide an in-coupling wave vector through which the input light rays are coupled into the waveguide substrate and transmitted;
the diffraction grating is configured to provide a first wave vector and a second wave vector, and the light rays transmitted in the waveguide substrate are subject to pupil expansion and out-coupled through the first wave vector and the second wave vector; the recovery grating is configured to provide a recovery wave vector to reflect the light rays interacted with the first wave vector or the second wave vector and transmitted to the recovery grating back to the diffraction grating, and the recovery wave vector is configured such that a wave vector space formed by at least portion of the input light rays, after passing through the in-coupling wave vector, the first wave vector or the second wave vector, the recovery wave vector and again the first wave vector and the second wave vector, is closed.

3 . The optical waveguide structure according to claim 2 , wherein the diffraction grating comprises a first grating, a second grating, and a third grating, where the first grating and the second grating are respectively disposed on opposite sides of the third grating, the first grating is at least configured to provide the first wave vector, the second grating is at least configured to provide the second wave vector, and the third grating is configured to provide the first wave vector or the second wave vector.

4 . The optical waveguide structure according to claim 3 , wherein the recovery grating comprises a first recovery grating disposed on a side of the third grating on which the first grating is disposed;
the first recovery grating is configured to provide a first recovery wave vector to reflect the light rays interacted with the second wave vector and transmitted to the first recovery grating back to the diffraction grating, the first recovery wave vector being configured such that a wave vector space formed by at least a portion of the input light rays, after passing through the in-coupling wave vector, the second wave vector, the first recovery wave vector, and again the first wave vector and the second wave vector, is closed.

5 . The optical waveguide structure according to claim 4 , wherein the first recovery wave vector is a wave vector difference between the first wave vector and the second wave vector.

6 . The optical waveguide structure according to claim 3 , wherein the recovery grating comprises a second recovery grating disposed on a side of the third grating on which the second grating is disposed;
the second recovery grating is configured to provide a second recovery wave vector to reflect the light rays interacted with the first wave vector and transmitted to the second recovery grating back to the diffraction grating, the second recovery wave vector being configured such that a wave vector space formed by at least a portion of the input light rays, after passing through the in-coupling wave vector, the first wave vector, the second recovery wave vector, and again the first wave vector and the second wave vector, is closed.

7 . The optical waveguide structure according to claim 6 , wherein the second recovery wave vector is a wave vector difference between the second wave vector and the first wave vector.

8 . The optical waveguide structure according to claim 1 , wherein the in-coupling grating is configured to provide an in-coupling wave vector through which the input light rays are coupled into the waveguide substrate and transmitted;
the diffraction grating is configured to provide a first wave vector and a second wave vector, and light rays transmitted in the waveguide substrate are subject to pupil expansion and out-coupled through the first wave vector and the second wave vector; the recovery grating is configured to provide a recovery wave vector to reflect the light rays transmitted to the recovery grating without interacting with the first wave vector and the second wave vector back to the diffraction grating, the recovery wave vector being configured such that a wave vector space formed by at least a portion of the input light rays, after passing through the in-coupling wave vector, the recovery wave vector, and the first wave vector and the second wave vector, is closed.

9 . The optical waveguide structure according to claim 8 , wherein the recovery grating comprises a third recovery grating disposed on a side of the diffraction grating opposite to the in-coupling grating;
the third recovery grating is provide a third recovery wave vector to reflect the light rays transmitted to the third recovery grating without interacting with the first wave vector and the second wave vector back to the diffraction grating, the third recovery wave vector being configured such that a wave vector space formed by at least a portion of the input light rays, after passing through the in-coupling wave vector, the third recovery wave vector, and the first wave vector and the second wave vector, is closed.

10 . The optical waveguide structure according to claim 9 , wherein the third recovery wave vector is twice the sum of the first wave vector and the second wave vector.

11 . An optical waveguide module, comprising:
an optical waveguide structure; and an optical engine configured to transmit input light rays to the in-coupling grating, wherein the optical waveguide structure comprises: a waveguide substrate; an in-coupling grating configured to in-couple input light rays into the waveguide substrate to transmit the light rays; a diffraction grating configured to perform pupil expansion on the light rays transmitted in the waveguide substrate and out-couple the light rays; and a recovery grating configured to reflect the light rays which are not out-coupled and are transmitted to the recovery grating back to the diffraction grating, wherein the recovery grating is configured such that a wave vector space formed by at least portion of input light rays, after interacting with the in-coupling grating, the diffraction grating and the recovery grating, is closed.

12 . The optical waveguide module according to claim 11 , wherein the in-coupling grating is configured to provide an in-coupling wave vector through which the input light rays are coupled into the waveguide substrate and transmitted;
the diffraction grating is configured to provide a first wave vector and a second wave vector, and the light rays transmitted in the waveguide substrate are subject to pupil expansion and out-coupled through the first wave vector and the second wave vector; the recovery grating is configured to provide a recovery wave vector to reflect the light rays interacted with the first wave vector or the second wave vector and transmitted to the recovery grating back to the diffraction grating

Assignees

• Lemon Inc
• Beijing Zitiao Network Technology Co Ltd

Inventors

• Zhang Peng
• Xiong Wen

Classifications

• G02B2006/12107

  Grating · CPC title

• G02B6/12

  of the integrated circuit kind (electric integrated circuits H10B, H10D84/00 - H10D89/00, H10F19/00, H10F39/00, H10H29/00, H10K19/00, H10K39/00, H10K59/00, H10N19/00, H10N39/00, H10N59/00, H10N69/00, H10N79/00, H10N89/00) · CPC title

• G02B5/18

  Diffraction gratings {(holographic optical elements G02B5/32, G03H; integrally combined with optical fibres G02B6/02057; for coupling light guides G02B6/34; integrally combined with optical integrated light guides G02B6/12; grating systems G02B27/44)} · CPC title

• G02B27/42

  Diffraction optics {, i.e. systems including a diffractive element being designed for providing a diffractive effect}(G02B27/60 takes precedence) · CPC title

• G02B27/0081

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