Light-emitting diode with light redirecting structure

1. A light-emitting diode (LED) comprising:

a semiconductor junction for emitting light upon application of electric current, the semiconductor junction comprising positive (p) and negative (n) regions; and

an optical surface coupled to the semiconductor junction and supported by one of the p- or n-regions for outputting at least a portion of the light emitted by the semiconductor junction, the optical surface comprising a redirecting structure comprising at least one of:

a plurality of features extending from the optical surface, or

a plurality of voids extending into the optical surface;

wherein the plurality of features or voids of the redirecting structure extend from the optical surface non-parallel to one another to focus the light outputted by the optical surface at a distance therefrom; and

wherein the redirecting structure is configured to redirect a chief ray of the portion of the light outputted by the optical surface from an initial direction to a pre-determined different direction.

2. The LED of claim 1 , wherein the optical surface is a top surface of the one of the p- or n-regions.

3. The LED of claim 1 further comprising a dielectric layer on top of the one of the p- or n-regions, wherein the optical surface is a top surface of the dielectric layer.

4. The LED of claim 1 , wherein the redirecting structure comprises at least one of: a grating structure, a prism, an off-center microlens, or a layer comprising a refractive index gradient.

5. The LED of claim 1 , wherein the redirecting structure comprises a layer having the plurality of voids therein, the voids having a laterally varying density for providing the refractive index gradient.

6. The LED of claim 1 , wherein the redirecting structure comprises a metamaterial grating structure.

7. The LED of claim 1 , wherein the plurality of features or voids comprises at least one of: rectangular features or voids; annular features or voids; cross-shaped features or voids; or chevron-shaped features or voids, respectively.

8. The LED of claim 1 , wherein the plurality of features or voids comprises slanted features or voids, respectively, extending at an acute angle from the optical surface.

9. The LED of claim 1 , wherein a size of the semiconductor junction is no greater than 6 microns by 6 microns.

10. A light-emitting diode (LED) array comprising:

a substrate;

an array of semiconductor junctions supported by the substrate and configured to emit light upon application of electric current; and

an array of optical surfaces each coupled to a particular one of the array of semiconductor junctions for outputting at least a portion of the light emitted thereby, wherein each optical surface of the array of optical surfaces comprises a redirecting structure configured to redirect a chief ray of the portion of the light outputted by the optical surface from an initial direction towards a center of the LED array;

wherein the semiconductor junctions each comprise positive (p) and negative (n) regions, wherein each optical surface of the array of optical surfaces is supported by one of the p- or n-regions of a corresponding semiconductor junction; and

wherein the redirecting structure comprises at least one of: a plurality of features extending from the optical surface, or a plurality of voids extending into the optical surface; wherein the plurality of features of voids of the redirecting structure extend from the optical surface non-parallel to one another to focus the light outputted by the optical surface at a distance therefrom.

11. The LED array of claim 10 , wherein each optical surface of the array of optical surfaces is a top surface of the corresponding one of the p- or n-regions.

12. The LED array of claim 10 further comprising a dielectric layer on top of each one of the p- or n-regions, wherein each optical surface is a top surface of the corresponding dielectric layer.

13. The LED array of claim 10 , wherein the redirecting structure is configured to provide a pre-defined divergence of the portion of the light outputted by the optical surface.

14. The LED array of claim 10 , wherein the redirecting structure comprises at least one of: a grating structure, a prism, an off-center microlens, a layer comprising a refractive index gradient, or a layer having a plurality of openings therein, the openings having a laterally varying density.

15. The LED array of claim 14 , wherein the redirecting structure comprises the grating structure, and wherein the grating structure comprises at least one of: an array of features extending from the optical surface; or an array of voids extending into the optical surface.

16. The LED array of claim 15 , wherein the array of features or voids comprises slanted features or voids, respectively, extending at an acute angle from the optical surface.

17. The LED array of claim 16 , wherein the slanted features or voids are inclined towards a center of the LED array.

18. A method of manufacturing a light-emitting diode (LED), the

method comprising:

providing a semiconductor junction for emitting light, the semiconductor junction comprising positive (p) and negative (n) regions;

providing an optical surface supported by one of the p- or n-regions for outputting at least a portion of the light, wherein the optical surface is coupled to the semiconductor junction; and

forming, in the optical surface or on the optical surface, a redirecting structure comprising at least one of:

a plurality of features extending from the optical surface, or

a plurality of voids extending into the optical surface;

wherein the plurality of features or voids of the redirecting structure extend from the optical surface non-parallel to one another to focus the light outputting by the optical surface at a distance therefrom; and

wherein the redirecting structure is configured to redirect a chief ray of the portion of the light outputted by the optical surface from an initial direction to a pre-determined different direction.