Shaping input surfaces of LED light-guides for increased light extraction efficiency

1. A system comprising:

a light-emitting diode (LED);

a light guide plate (LGP) comprising:

shaped injection surface;

a first surface comprising light extraction features, selected from one of a texture and a dot pattern;

a second surface opposite the first surface;

and

a third surface opposite the shaped injection surface;

a gap between the LED and the LGP; and

the shaped injection surface in contact with and extending between the first surface and the second surface, the shaped injection surface shaped to deviate near-parallel light emitted from the LED towards the first surface and the second surface.

2. The system of claim 1 , wherein the shaped injection surface is a split edge.

3. The system of claim 2 , wherein the split edge creates an input angle for light to enter the LGP at 10 degrees.

4. The system of claim 2 , wherein the split edge creates an input angle for light to enter the LGP at 20 degrees.

5. The system of claim 2 , wherein the split edge creates an input angle for light to enter the LGP at 30 degrees.

6. The system of claim 1 , wherein the shaped injection surface is a curved edge.

7. The system of claim 1 , wherein light rays emitted by the LED cross the shaped injection surface and are directed into the LGP at angles sufficiently high as to induce total internal reflection (TIR) of the light rays.

8. The system of claim 1 , wherein most light rays emitted by the LED do not propagate in the LGP at excessively high angles causing them to not be extracted by the light extraction features.

9. The system of claim 1 , wherein the shaped injection surface is angled to avoid inducing angles that are too high such that light rays emitted by the LED do not induce total internal reflection (TIR).

10. The system of claim 1 , wherein at least one of a geometry, shape, and size of the shaped injection surface on the input surface of the LGP is based on a distance of the LED to the LGP input surface.

11. A method comprising:

determining an angular distribution of a ray set of a light-emitting diode (LED);

determining a first shaped injection surface of a light guide plate (LGP) based on the angular distribution of the ray set of the LED, the shaped injection surface in contact with and extending between a first surface and a second surface, the second surface opposite the first surface, the LGP comprising light extraction features on the first surface, a third surface of the LGP opposite the shaped injection surface, the second surface connecting the shaped injection surface and the third surface; and

applying the first shape of the injection surface to the LGP, such that the shape of the injection surface is substantially perpendicular to the first surface, the shaped injection surface shaped to deviate near-parallel light emitted from the LED towards the first surface and the second surface.

12. The method of claim 11 , wherein the applying includes using a manufacturing process that uses a drill to create the first shape.

13. The method of claim 11 , wherein the shape of the injection surface is a split edge.

14. The method of claim 11 , wherein the shape of the injection surface is a curved edge.

15. The method of claim 11 , wherein light rays emitted by the LED cross the shape of the injection surface and are directed into the LGP at angles sufficiently high as to induce total internal reflection (TIR) of the light rays.

16. The method of claim 11 , wherein most light rays emitted by the LED do not propagate in the LGP at excessively high angles causing them to not be extracted by light extraction features of the LGP.

17. The method of claim 11 , wherein the shape of the injection surface is angled to avoid inducing angles that are too high such that light rays emitted by the LED do not induce total internal reflection (TIR).

18. The method of claim 11 , wherein at least one of a geometry, shape, and size of the shape of the injection surface of the LGP is based on a distance of the LED to the injection surface of the LGP.

19. A light guide plate (LGP) system comprising:

a light-emitting diode (LED);

a shaped injection surface;

a first surface;

a second surface opposite the first surface;

a third surface opposite the shaped injection surface;

light extraction features selected from one of a texture and a dot pattern and located on the first surface of the LGP; and

a gap between the LED and LGP;

the shaped injection surface in contact with and extending between the first surface and the second surface, the shaped injection surface.

20. The LGP system of claim 19 , wherein the shaped injection surface is a split edge or curved edge.

21. The system of claim 1 , wherein the shaped injection surface is concave to the LED.

22. The system of claim 1 , wherein the first surface is perpendicular to the direction of the near-parallel light emitted from the LED.

23. The method of claim 11 , wherein the shaped injection surface is angled to deviate near-parallel light emitted from the LED to enable the near-parallel light emitted from the LED to be extracted from the LGP via the light extraction features.

24. The system of claim 1 , wherein the light extraction features are on a same plane as a plane of the near-parallel light emitted from the LED.

25. The system of claim 1 , wherein the shaped injection surface is between the LED and the third surface.

26. The system of claim 1 , wherein the near-parallel light emitted from the LED is perpendicular to the third surface.