Arrayed waveguide, display device and spectacles device

1. An arrayed waveguide, comprising:

a first waveguide layer and a second waveguide layer which are stacked;

wherein the first waveguide layer comprises a first main expanding portion comprising a plurality of first optical medium layers sequentially arranged in a first direction, the plurality of first optical medium layers are configured to expand, in the first direction, a first light beam incident into the first main expanding portion and to reflect the expanded first light beam toward the second waveguide layer, and at least one of the plurality of first optical medium layers is configured to transmit a portion of the first light beam and reflect another portion of the first light beam, and

the second waveguide layer comprises a second main expanding portion comprising a plurality of second optical medium layers sequentially arranged in a second direction, the plurality of second optical medium layers are configured to expand, in the second direction, a second light beam incident into the second main expanding portion and reflect the expanded second light beam to exit from a side of the second waveguide layer that faces away from the first waveguide layer, the second main expanding portion are further configured to transmit the expanded first light beam through the second main expanding portion, and at least one of the plurality of second optical medium layers are configured to transmit a portion of the second light beam and reflect another portion of the second light beam,

wherein an angle between the first direction and the second direction is greater than 0 degree and less than 180 degrees,

wherein the first waveguide layer further comprises a first auxiliary expanding portion comprising a plurality of third optical medium layers sequentially arranged in the second direction, the plurality of third optical medium layers are configured to expand, in the second direction, a third light beam incident into the first auxiliary expanding portion to form the first light beam and to reflect the first light beam toward the first main expanding portion, and at least one of the plurality of third optical medium layers are configured to transmit a portion of the third light beam and reflect another portion of the third light beam, and

wherein the second waveguide layer further comprises a second auxiliary expanding portion comprising a plurality of fourth optical medium layers sequentially arranged in the first direction, the plurality of fourth optical medium layers are configured to expand, in the first direction, a fourth light beam incident into the second auxiliary expanding portion to form the second light beam and to reflect the second light beam toward the second main expanding portion, and at least one of the plurality of fourth optical medium layers are configured to transmit a portion of the fourth light beam and reflect another portion of the fourth light beam.

2. The arrayed waveguide of claim 1 , wherein, the first waveguide layer further comprises a first light incident portion for receiving a fifth light beam, the first light incident portion is provided with a beam splitting surface, and the beam splitting surface is configured to reflect a portion of the fifth light beam toward the first auxiliary expanding portion to form the third light beam and transmit another portion of the fifth light beam toward the second waveguide layer to form the fourth light beam; and

the second waveguide layer further comprises a second light incident portion for receiving the fourth light beam, the second light incident portion is provided with a light reflecting surface, and the light reflecting surface is configured to reflect the fourth light beam into the second auxiliary expanding portion.

3. The arrayed waveguide of claim 2 , wherein an optical element for changing a polarization state of light is provided between the first light incident portion and the second light incident portion.

4. The arrayed waveguide of claim 2 , wherein the optical element comprises a half-wave plate.

5. The arrayed waveguide of claim 2 , wherein, the beam splitting surface has a transmission reflection ratio of 1:1, and the light reflecting surface has a transmission reflection ratio of 0.

6. A display device, comprising:

the arrayed waveguide according to claim 2 ; and

a light beam projector configured to project the fifth light beam to the first light incident portion of the first waveguide layer.

7. The arrayed waveguide of claim 1 , wherein the first direction and the second direction are perpendicular to each other.

8. The arrayed waveguide of claim 1 , wherein, at least one of the plurality of first optical medium layers and at least one of the plurality of third optical medium layers are partially transmissive and partially reflective for a first linearly polarized light; and

at least one of the plurality of the second optical medium layers and at least one of the plurality of fourth optical medium layers are partially transmissive and partially reflective for a second linearly polarized light and are at least partially transmissive for the first linearly polarized light, and a polarization direction of the first linearly polarized light is perpendicular to a polarization direction of the second linearly polarized light.

9. The arrayed waveguide of claim 1 , wherein,

each of the first optical medium layers has an angle of 40° to 50° with respect to a first plane;

each of the second optical medium layers has an angle of 40° to 50° with respect to the first plane;

each of the third optical medium layers has an angle of 40° to 50° with respect to a second plane;

each of the fourth optical medium layers has an angle of 40° to 50° with respect to the second plane; and

the first plane is a plane that is parallel to the first direction and parallel to the second direction; and the second plane is a plane that is parallel to the first direction and parallel to a third direction which is perpendicular to both the first direction and the second direction.

10. The arrayed waveguide of claim 9 , wherein,

each of the first optical medium layers has an angle of 45° with respect to the first plane;

each of the second optical medium layers has an angle of 45° with respect to the first plane;

each of the third optical medium layers has an angle of 45° with respect to the second plane; and

each of the fourth optical medium layers has an angle of 45° with respect to the second plane.

11. The arrayed waveguide of claim 1 , wherein transmission reflection ratios of the plurality of first optical medium layers to the first light beam are decreased downstream along an optical path of the first light beam in the first direction.

12. The arrayed waveguide of claim 11 , wherein one of the plurality of first optical medium layers that is located the most downstream of the optical path in the first direction has a transmission reflection ratio of 0 to the first light beam.

13. The arrayed waveguide of claim 1 , wherein transmission reflection ratios of the plurality of second optical medium layers to the second light beam are decreased downstream along an optical path of the second light beam in the second direction.

14. The arrayed waveguide of claim 13 , wherein one of the plurality of second optical medium layers that is located the most downstream of the optical path in the second direction has a transmission reflection ratio of 0 to the second light beam.

15. The arrayed waveguide of claim 1 , wherein the first light beam is a first linearly polarized light while the second light beam is a second linearly polarized light, and a polarization direction of the first linearly polarized light is perpendicular to a polarization direction of the second linearly polarized light.

16. A display device, comprising:

the arrayed waveguide according to claim 1 .

17. A spectacles device, comprising a lens having the arrayed waveguide according to claim 1 .

18. The arrayed waveguide of claim 1 , wherein the first light beam and the second light beam are formed by the same light beam.

19. The arrayed waveguide of claim 1 , wherein the plurality of first optical medium layers are arranged equidistantly and the plurality of second optical medium layers are arranged equidistantly.