Optical display system and augmented reality electronic device

Patent metadata

Field	Value
Publication number	US-12140754-B2
Application number	US-202117566019-A
Country	US
Kind code	B2
Filing date	Dec 30, 2021
Priority date	Dec 30, 2021
Publication date	Nov 12, 2024
Grant date	Nov 12, 2024

Abstract

An optical display system and an augmented reality electronic device are disclosed. The optical display system comprises: a waveguide; an input coupler, provided at the input end of the waveguide and couples an image light into it; and a two-dimensional grating, provided at the output end of waveguide. The waveguide delivers the image light to the two-dimensional grating, which performs pupil expansion on the image light and out-couples the expanded image light. The two-dimensional grating has rhombus lattices. Unit cells of the two-dimensional grating are un-symmetric along respective axes parallel with a propagation direction of the image light incident onto the two-dimensional grating, from a top view of the two-dimensional grating. The unit cells are oriented with the propagation direction of the image light and each of the unit cells has at least two vertexes at its end side.

First claim

What is claimed is:

1. An optical display system, comprising:
a waveguide,
an input coupler, which is provided at the input end of the waveguide and couples an image light into the waveguide; and
a two-dimensional grating, which is provided at the output end of the waveguide,
wherein the waveguide delivers the image light coupled by the input coupler to the two-dimensional grating, and the two-dimensional grating performs pupil expansion on the image light and out-couples the expanded image light,
wherein the two-dimensional grating has rhombus lattices,
wherein a plurality of unit cells of the two-dimensional grating are un-symmetric along respective axes parallel with a propagation direction of the image light incident onto the two-dimensional grating, from a top view of the two-dimensional grating, and
wherein the plurality of unit cells are oriented with the propagation direction of the image light and each of the plurality of unit cells has at least two vertexes at its end side.

2. The optical display system according to claim 1 , wherein an index of the two-dimensional grating is equal to or larger than 1.7 or 1.8.

3. The optical display system according to claim 1 , wherein a thickness of the two-dimensional grating is equal to or smaller than 200 nm or 100 nm.

4. The optical display system according to claim 1 , wherein the plurality of unit cells are oriented with the propagation direction of the image light and vertex angles of the unit cells starting from orientation positions are larger than 45 degree and smaller than 60 degree.

5. The optical display system according to claim 1 , wherein the plurality of unit cells have waists along the propagation direction.

6. The optical display system according to claim 5 , wherein a part of each of the plurality of unit cells before the waist is longer than that after the waist along the propagation direction.

7. The optical display system according to claim 5 , wherein the plurality of unit cells have thickness factors along the waist larger than those of other portions.

8. The optical display system according to claim 1 , wherein the plurality of unit cells are connected into a closed shape.

9. The optical display system according to claim 7 , wherein parts of the two-dimensional grating enclosed by the plurality of unit cells have a lower index and form low index unit cells, which are un-symmetric along respective axes parallel with the propagation direction and each of which has at least two vertexes at its end side.

10. The optical display system according to claim 1 , wherein the waveguide is a one-layer waveguide and the input coupler and the two-dimensional grating are formed on or in the one-layer waveguide.

11. The optical display system according to claim 1 , wherein the plurality of unit cells have diamond-like bow-tie shapes.

12. The optical display system according to claim 1 , wherein the rhombus lattices are ±30 degree related to the propagation direction.

13. The optical display system according to claim 1 , wherein a duty cycle of the two-dimension grating ranges from 0.5 to 0.95.

14. The optical display system according to claim 1 , wherein the two-dimension grating is a surface relief grating.

15. An augmented reality electronic device, including:
a display, which generates an image light; and
the optical display system according to claim 1 , which receives the image light and guides it to an eye.

Assignees

• Goertek Inc

Inventors

• Li Lingshan

Classifications

• G02B27/4205

  having a diffractive optical element [DOE] contributing to image formation, e.g. whereby modulation transfer function MTF or optical aberrations are relevant · CPC title

• G02B27/0172 Primary

  characterised by optical features · CPC title

• G02B6/29323

  Coupling to or out of the diffractive element through the lateral surface of the light guide (evanescent grating couplers G02B6/29332) · CPC title

• G02B2027/0123

  comprising devices increasing the field of view · CPC title

• G02B27/0081 Primary

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