Light mixing systems with a glass light pipe

1. An optical system, comprising

a glass light pipe having an input surface for receiving light from a light source and an output surface through which light exits the light pipe;

a polymeric light-shaping element, the polymeric light-shaping element having an input surface and an output surface, wherein the input surface of the polymeric light-shaping element is optically coupled to the output surface of the glass light pipe and configured to receive at least a portion of the light exiting the output surface of the glass light pipe, and the output surface of said polymeric light-shaping element comprises a plurality of microlenses; and

a projection lens optically coupled to the output surface of the polymeric light-shaping element to receive light therefrom.

2. The optical system of claim 1 , wherein at least one of said microlenses comprises a textured surface.

3. The optical system of claim 2 , wherein said textured surface comprises a plurality of surface undulations characterized by heights in a range of about 0.01 mm to about 0.05 mm.

4. The optical system of claim 1 , wherein said input surface of the light-shaping element is a textured surface.

5. The optical system of claim 4 , wherein said textured input surface of the light-shaping element comprises a plurality of surface undulations characterized by heights in a range of about 0.01 mm to about 0.05 mm.

6. The optical system of claim 1 , wherein said light-shaping element has a thickness in a range of about 0.5 mm to about 3 mm.

7. The optical system of claim 1 , wherein said glass light pipe is tapered such that said input surface thereof has a smaller surface area than that of its output surface.

8. The optical system of claim 7 , wherein said tapered glass light pipe has a draft angle equal to or less than about 20 degrees.

9. The optical system of claim 1 , wherein said light source comprises at least one light emitting diode (LED).

10. The optical system of claim 9 , wherein said light source comprises two light sources providing light of different colors.

11. The optical system of claim 1 , wherein said glass light pipe comprises a polygonal cross section.

12. The optical system of claim 11 , wherein said polygonal cross section is selected from the group consisting of a square, a rectangular, a hexagonal and an octagonal cross section.

13. The optical system of claim 1 , wherein said glass light pipe comprises two portions with different cross-sectional profiles.

14. An optical system, comprising:

a light pipe having a glass portion and a polymeric portion, said glass portion providing an input surface for receiving light from a light source and said polymeric portion providing an output surface through which light exits the light pipe, the light pipe having a polygonal cross section;

a polymeric light-shaping element, the polymeric light-shaping element having an input surface and an output surface, wherein the input surface of the polymeric light-shaping element is optically coupled to the output surface of the light pipe and configured to receive at least a portion of the light exiting the output surface of the light pipe, and the output surface of the polymeric light-shaping element comprises a plurality of microlenses; and

a projection lens optically coupled to the output surface of the polymeric light-shaping element to receive light therefrom.

15. The optical system of claim 14 , wherein said output surface includes textures characterized by heights in a range of about 0.01 mm to about 0.05 mm.

16. An optical system, comprising:

a glass light pipe extending from an input surface for receiving light from a light source to an output surface through which light exits the light pipe, the glass light pipe having a polygonal cross section;

a polymeric light-shaping element, the polymeric light-shaping element having an input surface and an output surface, wherein the input surface of the polymeric light-shaping element is optically coupled to the output surface of the glass light pipe and configured to receive at least a portion of the light exiting the output surface of the glass light pipe, and the output surface of the polymeric light-shaping element comprises a plurality of microlenses; and

a projection lens optically coupled to the output surface of the polymeric light-shaping element and configured to receive light therefrom.

17. The optical system of claim 16 , further comprising a plurality of microlenses coupled to said output surface of the light pipe, wherein each of said microlenses provides a curved surface through which light exits the microlens.

18. The optical system of claim 17 , wherein at least one of said microlenses includes textures on its curved surface characterized by a height in a range of about 0.01 mm to about 0.25 mm.

19. The optical system of claim 16 , wherein said microlenses are integrally formed with said light pipe.

20. The optical system of claim 16 , wherein said microlenses are formed on a surface of a separate light-shaping element that is optically coupled to the output surface of the light pipe.

21. The optical system of claim 16 , wherein said light pipe is tapered such that said input surface thereof has a smaller surface area than that of its output surface.

22. The optical system of claim 21 , wherein said tapered glass light pipe comprises a draft angle equal to or less than about 20 degrees.

23. The optical system of claim 16 , wherein said polygonal cross section is selected from the group consisting of a square, a rectangular, a hexagonal and an octagonal cross section.

24. The optical system of claim 16 , wherein said glass light pipe comprises two portions with different cross-sectional profiles.