3D display directional backlight based on diffractive elements

1. An apparatus for displaying a three-dimensional (3D) content, comprising:

an addressable array of light-emitting elements;

an array of collimating optical elements, configured to collimate light emitted by the array of light-emitting elements into a plurality of collimated light beams;

one or more diffractive grating layers, configured to diffract each of the collimated light beams into a plurality of diffracted light beams propagating in different angular directions; and

an array of optical mask elements synchronized, based on 3D geometry and visual information representative of the 3D content, to the addressable array of light-emitting elements to enable viewing beams, of the diffracted light beams, propagating in respective angular directions, wherein the viewed beams represent a voxel at a spatial location in the content displayed.

2. The apparatus of claim 1 ,

wherein the addressable array of light-emitting elements comprises a plurality of sets of light-emitting elements, and

wherein each collimating optical element of the array of collimating optical elements is associated with a particular set of light-emitting elements of the plurality of sets of light-emitting elements.

3. The apparatus of claim 1 , wherein one or more of the light-emitting elements of the addressable array of light-emitting elements is selected from a group consisting of a μLED and an OLED.

4. The apparatus of claim 1 , wherein the array of optical mask elements is a spatial light modulator (SLM).

5. The apparatus of claim 1 , wherein the array of optical mask elements is a liquid crystal display (LCD).

6. The apparatus of claim 1 , further comprising a color filter.

7. The apparatus of claim 1 , further comprising an optical element, wherein the optical element is configured to adjust emission direction angles of one or more of the optical mask elements.

8. The apparatus of claim 7 , wherein the optical element is configured to adjust the emission direction angles of the one or more of the optical mask elements to align with a viewing window of a viewer.

9. The apparatus of claim 1 ,

wherein the addressable array of light-emitting elements comprises a first group of sets of light-emitting elements and a second group of sets of light-emitting elements,

wherein the sets of light-emitting elements of the first group are each located less than a threshold distance away from a center of the apparatus and are arranged with an equal separation between each other, and

wherein the sets of light-emitting elements of the second group are each located more than the threshold distance away from the center of the apparatus and are arranged with an unequal separation between each other based on how far each of the sets of light-emitting elements of the second group is located from the center of apparatus.

10. The apparatus of claim 1 , wherein the one or more diffractive grating layers are passive, continuously-diffractive structures.

11. The apparatus of claim 1 , wherein the array of optical mask elements is synchronized to the addressable array of light-emitting elements by:

transforming the 3D geometry and the visual information into control parameters; and

activating, based on the control parameters, the light-emitting elements and the optical mask using spatial and temporal multiplexing to generate a 3D image of the 3D content.

12. A method for displaying a three-dimensional (3D) content comprising:

emitting a light beam from each light-emitting element of an addressable array of light-emitting elements to generate a plurality of light beams;

collimating each of the plurality of light beams to generate a plurality of collimated light beams;

diffracting each of the plurality of collimated light beams to generate a plurality of diffracted light beams propagating in different angular directions; and

synchronizing, based on 3D geometry and visual information representative of the 3D content, an optical mask to the addressable array of light-emitting elements to enable viewing beams, of the diffracted light beams, propagating in respective angular directions, wherein the viewed beams represent a voxel at a spatial location in the content displayed.

13. The method of claim 12 , wherein synchronizing the optical mask to the addressable array of light-emitting elements comprises selectively passing and blocking the diffracted light beams based on the content embodied in the diffracted light beams.

14. The method of claim 13 , wherein selectively passing and blocking the diffracted light beams based on the content comprises:

spatially multiplexing control of the optical mask to selectively pass and block the diffracted light beams based on the content; and

temporally multiplexing control of the optical mask to selectively pass and block the diffracted light beams based on the content.

15. The method of claim 12 , wherein synchronizing the optical mask to the addressable array of light-emitting elements comprises:

rendering a three-dimensional (3D) image by projecting 3D image data of the 3D content at different angular directions using sequential activation of the light-emitting elements and the optical mask according to the angular directions.

16. The method of claim 12 , wherein synchronizing the optical mask to the addressable array of light-emitting elements comprises:

determining a location of a multidirectional display pixel (MDP) within the optical mask based on a selected light beam selected from the plurality of diffracted light beams and the content embodied in the plurality of diffracted light beams; and

rendering the optical mask,

wherein the selected light beam selected from the plurality of diffracted light beams passes through the optical mask, and

wherein rendering the optical mask synchronizes the optical mask with the content embodied in the plurality of diffracted light beams.

17. The method of claim 12 , wherein synchronizing the optical mask to the addressable array of light-emitting elements enables more than one diffracted light beam, of the plurality of diffracted light beams, per pixel of the optical mask to pass through the optical mask.

18. The method of claim 12 , further comprising adjusting emission direction angles of the optical mask.

19. The method of claim 18 , wherein adjusting the emission direction angles of the optical mask adjusts the emission direction angles of the optical mask to align with a viewing window of a viewer.

20. The method of claim 12 , further comprising:

tracking eye positions of a viewer,

wherein synchronizing the optical mask to the addressable array of light-emitting elements comprises:

selecting a portion of the addressable array of light-emitting elements based on the eye positions of the viewer; and

synchronizing the optical mask to the selected portion of the addressable array of light-emitting elements.

21. The method of claim 12 , further comprising adjusting a brightness of the plurality of light beams by pulse width modulating the light beam emitted from each light-emitting element of the addressable array of light-emitting elements.

22. The method of claim 12 , wherein synchronizing of the optical mask to the addressable array of light-emitting elements comprises:

transforming the 3D geometry and the visual information into control parameters; and

activating, based on the control parameters, the light-emitting elements and the optical mask using spatial and temporal multiplexing to generate a 3D image of the 3D content.