Optical waveguide structure and display device

Abstract

The present disclosure provides an optical waveguide structure including an optical waveguide, a coupling-in grating, and a coupling-out grating, the coupling-in grating and the coupling-out grating are on a same surface of the optical waveguide and are spaced apart from each other. The optical waveguide includes a first light-guiding portion and a second light-guiding portion spliced with each other. A refractive index of the first light-guiding portion is less than a refractive index of the second light-guiding portion. Orthographic projections of the coupling-in grating and the coupling-out grating on the optical waveguide are on the first light-guiding portion. The coupling-in grating is used to couple an image light into the optical waveguide, so that the image light passes through the first light-guiding portion, the second light-guiding portion and the first light-guiding portion in sequence and coupled out of the optical waveguide through the coupling-out grating. The present disclosure also provides a display device.

Claims

1. An optical waveguide structure, improved in that it includes an optical waveguide and coupling gratings and coupling gratings located on the same surface of the optical waveguide and spaced apart; the optical waveguide includes a first light guide portion and a second light guide portion spliced ​​together, the refractive index of the first light guide portion is less than the refractive index of the second light guide portion, and the orthogonal projections of the coupling gratings and the coupling gratings on the optical waveguide along the thickness direction of the optical waveguide are located on the first light guide portion; the coupling grating is used to couple image light into the optical waveguide, so that the image light passes sequentially through the first light guide portion, the second light guide portion, and the first light guide portion before being coupled out of the optical waveguide from the coupling grating.

2. The optical waveguide structure as described in claim 1, wherein, The optical waveguide includes a first surface and a second surface spaced apart and facing away from each other. The first light guide portion and the second light guide portion are flush in the thickness direction of the optical waveguide. The first surface and the second surface are both formed by the first light guide portion and the second light guide portion.

3. The optical waveguide structure as described in claim 2, wherein, The second light guide portion includes a first side surface and a second side surface connected to the first light guide portion, and the first side surface and the second side surface are arranged sequentially at intervals in the direction from the coupled-in grating to the coupled-out grating.

4. The optical waveguide structure as described in claim 3, wherein, Both the first side and the second side are planes, and the first side and the second side are parallel to each other.

5. The optical waveguide structure as described in claim 4, wherein, The first side and the second side are perpendicular to the first surface.

6. The optical waveguide structure as described in claim 3, wherein, Both the first side and the second side are smooth curved surfaces, and both the first side and the second side are curved toward the coupling grating.

7. The optical waveguide structure as described in claim 6, wherein, Both the first side and the second side are spherical surfaces, and the curvature of the second side is less than or equal to the curvature of the first side.

8. The optical waveguide structure as described in claim 7, wherein, The optical waveguide structure satisfies the following relationship: n2×(R2-R1+d)-d×n1=0, where n1 is the refractive index of the first light guide part, n2 is the refractive index of the second light guide part, R1 is the radius of curvature of the first side surface, R2 is the radius of curvature of the second side surface, and d is the shortest distance between the first side surface and the second side surface.

9. The optical waveguide structure as described in any one of claims 1 to 8, wherein, The refractive index of the second light guide portion ranges from 1.3 to 2.

5.

10. The optical waveguide structure as described in any one of claims 1 to 8, wherein, Both the first light guide and the second light guide are transparent solid structures.

11. The optical waveguide structure as described in any one of claims 1 to 8, wherein, The first light guide is a transparent solid structure, and the second light guide is a transparent liquid structure.

12. The optical waveguide structure as described in any one of claims 1 to 8, wherein, The first light guide portion includes a first part and a second part that are separated from each other. The first part and the second part are respectively connected to the two ends of the second light guide portion and are flush with the second light guide portion in the thickness direction. The coupling grating is located on the surface of the first part and the coupling grating is located on the surface of the second part. The coupling grating is used to couple the image light into the first part, so that the image light passes through the first part, the second light guide portion, and the second part in sequence and is coupled out of the second part from the coupling grating.

13. The optical waveguide structure as described in any one of claims 1 to 8, wherein, The first light guide portion is arranged around the second light guide portion.

14. A display device, improved in that it comprises: A monitor is used to emit light for images; And an optical waveguide structure as claimed in any one of claims 1 to 13, wherein the coupling grating is located in the optical path of the image light for coupling the image light into the optical waveguide.

15. The display device as claimed in claim 14, wherein, The display device further includes a collimating lens located between the monitor and the coupling grating, used to convert the image light from the monitor into a parallel beam before it is emitted to the coupling grating.

16. The display device as claimed in claim 14, wherein, The display device is an AR near-eye display device or an AR head-up display device.

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