Optical system for a digital light projection system including optical concentrator elements having reflective aperture elements

• US 20070132959A1
• Filed: 06/02/2006
• Published: 06/14/2007
• Est. Priority Date: 12/09/2005
• Status: Active Grant

• Current Assignee: SCRAM Technologies, Inc
• Original Assignee: SCRAM Technologies, Inc
• Inventors: Liu, Rong, Shanley, James
• Granted Patent: US 7,369,316 B2
• Time in Patent Office: Days
• US Class Current: 353/31
• CPC Class Codes: G03B 21/2013 Plural light sources
• CPC Class Codes: G03B 21/2033 LED or laser light sources
• CPC Class Codes: G03B 21/208 Homogenising, shaping of the illumination light
• CPC Class Codes: G03B 33/06 by additive-colour projection apparatus
• CPC Class Codes: H04N 9/3152 for shaping the light beam beam shaping per se G02B27/09

Abstract

An optical system for a digital light projection system is provided. The optical system comprises a plurality of LED arrays, wherein each LED array comprises a plurality of LEDs. The optical system also comprises an optical concentrator element positioned substantially adjacent to each of the LED arrays, wherein each concentrator element reflects light emitted from the plurality of LEDs within the corresponding LED array. The optical system preferably further comprises a reflective aperture element positioned substantially adjacent to the output surface of each concentrator element. The aperture element includes a reflective surface and an aperture defined by the reflective surface. The reflective surface faces the output surface of each corresponding concentrator element to thereby ultimately provide substantially uniform light which is projected through the aperture.

Claims

1. An optical system for a digital light projection system, the optical system comprising:

at least one LED array, wherein each LED array comprises a plurality of LEDs; and

an optical concentrator element positioned substantially adjacent to each LED array, wherein each concentrator element reflects light emitted from the plurality of LEDs within the corresponding LED array so as to provide reflected light at an output surface of each concentrator element; and

an aperture element positioned substantially adjacent to the output surface of each concentrator element, wherein the aperture element includes a reflective surface and an aperture defined by the reflective surface, wherein the reflective surface faces the output surface of each concentrator element such that a first portion of the reflected light is intended for projection through the aperture without reflection by the reflective surface, while a second portion of the reflected light is reflected by the reflective surface back into the concentrator element to thereby provide light which is additionally reflected within the concentrator element, and wherein the first portion of the reflected light and the additionally reflected light is spatially combined at the output surface of each concentrator element at the aperture to thereby provide substantially uniform light which is projected through the aperture.

2. The optical system of claim 1, wherein the aperture element comprises a reflective coating which has the reflective surface located on the output surface of each concentrator element.

3. The optical system of claim 1, wherein the aperture element comprises a reflective plate which has the reflective surface facing the output surface of each concentrator element.

4. The optical system of claim 1, wherein the aperture is rectangular.

5. The optical system of claim 1, wherein the aperture has an aspect ratio other than 1:

1.

6. The optical system of claim 1, wherein the aperture has an aspect ratio of 16:

9.

7. The optical system of claim 1, wherein the output surface of each concentrator element is planar.

8. The optical system of claim 1, wherein the output surface of each concentrator element is planar and forms an angle other than 90°

with respect to a longitudinal direction of the concentrator element.

9. The optical system of claim 1, wherein the output surface of each concentrator element is curved.

10. The optical system of claim 1, wherein the output surface of each concentrator element is curved only in locations adjacent the reflective surface.

11. The optical system of claim 1, wherein the output surface of each concentrator element is curved only in locations adjacent the aperture.

12. The optical system of claim 1, wherein the output surface of each concentrator element is diffusive.

13. The optical system of claim 1, wherein the output surface of each concentrator element is diffusive only in locations adjacent the reflective surface.

14. The optical system of claim 1, wherein the output surface of each concentrator element is diffractive.

15. The optical system of claim 1, wherein the output surface of each concentrator element is diffractive only in locations adjacent the reflective surface.

16. The optical system of claim 1, wherein the output surface of each concentrator element is faceted.

17. The optical system of claim 1, wherein the output surface of each concentrator element is faceted only in locations adjacent the reflective surface.

18. The optical system of claim 1, wherein the output surface of each concentrator element comprises lenslets.

19. The optical system of claim 1, wherein the output surface of each concentrator element comprises lenslets only in locations adjacent the reflective surface.

20. The optical system of claim 1, wherein the reflective surface is diffusive.

21. The optical system of claim 1, wherein the reflective surface is diffractive.

22. The optical system of claim 1, wherein the reflective surface is faceted.

23. The optical system of claim 1, wherein the reflective surface comprises lenslets.

24. The optical system of claim 1, wherein the concentrator element is positioned directly in contact with each corresponding LED array.

25. The optical system of claim 1 further comprising an optical coupling material positioned between the concentrator element and each corresponding LED array, wherein the optical coupling material is in contact with the concentrator element and each corresponding LED array.

26. The optical system of claim 25, wherein the optical coupling material comprises a gel having an index of refraction which substantially matches that of the concentrator element.

27. The optical system of claim 1, wherein each LED array comprises LEDs which are less than 0.35 mm in width.

28. The optical system of claim 1, wherein each LED array comprises LEDs which are spaced from adjacent LEDs within the same array by an amount less than 0.025 mm.

29. The optical system of claim 1, wherein the concentrator element has a conic shape.

30. The optical system of claim 1, wherein the concentrator element has a complex conic shape.

31. The optical system of claim 1, wherein the concentrator element has a substantially parabolic cross section.

32. The optical system of claim 1, wherein the concentrator element comprises a material selected from the group consisting of a polymer, plastic, glass, metal, and combinations thereof.

33. The optical system of claim 1, wherein the concentrator element comprises Zeonex®

.

34. The optical system of claim 1, wherein the reflection of light performed by each concentrator element is total internal reflection.

35. The optical system of claim 1, wherein the reflection of light performed by each concentrator element is specular reflection.

36. The optical system of claim 1, wherein a specularly reflective element is positioned only on a limited portion of an outer surface of each concentrator element which is in the vicinity of each corresponding LED array such that the reflection of light performed by each concentrator element comprises specular reflection and total internal reflection.

37. The optical system of claim 1, wherein each concentrator element is solid.

38. The optical system of claim 1, wherein each concentrator element is hollow.

39. The optical system of claim 1, wherein the optical system is an illumination optical system.

40. The optical system of claim 1 further comprising a digital imaging device.

41. The optical system of claim 40, wherein the output surface of each concentrator element is imaged directly on the digital imaging device.

42. The optical system of claim 40, wherein the imaging device has an aspect ratio other than 1:

1.

43. The optical system of claim 40, wherein the imaging device has an aspect ratio of 16:

9.

44. The optical system of claim 1, wherein the plurality of LEDs within each LED array is of substantially the same color.

45. The optical system of claim 1, wherein the plurality of LEDs within each LED array comprise a plurality of colors.