Polarization preserving front projection screen microstructures

• US 8,711,477 B2
• Filed: 11/07/2011
• Issued: 04/29/2014
• Est. Priority Date: 01/28/2008
• Status: Active Grant

• Current Assignee: RealD Incorporated
• Original Assignee: RealD Incorporated
• Inventors: Coleman, David A., Sharp, Gary D.
• Primary Examiner(s): MAHONEY, CHRISTOPHER E
• Application Number:
  US13/290,978
• Publication Number:
  US 20120113508A1
• Time in Patent Office: 904 Days
• Field of Search: 359/449, 359/451, 359/459
• US Class Current: 359/459
• CPC Class Codes: F16H 21/14 by means of cranks, eccentrics, or like members fixed to one rotary member and guided along tracks on the other
• CPC Class Codes: G02B 30/25 using polarisation techniques
• CPC Class Codes: G03B 21/60 characterised by the nature of the surface
• CPC Class Codes: G03B 35/16 by sequential viewing
• CPC Class Codes: G03B 35/26 using polarised or coloured light separating different viewpoint images
• CPC Class Codes: Y10T 428/24802 Discontinuous or differential coating, impregnation or bond [e.g., artwork, printing, retouched photograph, etc.]
• CPC Class Codes: Y10T 74/18232 Crank and lever

Abstract

Polarization preserving front projection screens and diffusers provide optimum polarization preservation for stereoscopic 3D viewing, as well as improved light control for enhanced brightness, uniformity, and contrast for both 2D and 3D systems. Generally, the disclosed screens direct light from a projector toward viewers within a diffusion locus, while maintaining optimum gain characteristics. More specifically, light incident on a region of the front projection screen from a predetermined projection direction is reflected by an engineered surface to a predetermined diffusion locus after undergoing substantially single reflections. The engineered surface, comprised of generating kernels, is used to optimally diffuse illumination light into a range of viewing angles, within the diffusion locus, with suitable gain profile, while optimally preserving polarization for 3D applications. Such a screen, when combined with matched polarization analyzing eyewear, provides extremely low cross-talk from any observation point.

Claims

1. A projection screen, comprising:

a contoured reflective surface having a predetermined scatter profile, the predetermined scatter profile being operable to reflect incident light from a predetermined incident angle range to within a diffusion locus,

wherein the light reflected from the predetermined incident angle range to within the diffusion locus substantially undergoes no more than one reflection from the contoured reflective surface, wherein the diffusion locus is defined by a region in which reflections within the diffusion locus substantially undergo no more than one reflection on the contoured reflective surface, and wherein light reflected outside of the diffusion locus undergoes one or more reflections on the contoured reflective surface.

2. The projection screen of claim 1, wherein the incident light is polarized light, and wherein light reflected from the predetermined incident angle range to within the diffusion locus maintains the same state of polarization.

3. The projection screen of claim 1, wherein the contoured reflective surface comprises a plurality of generating kernels.

4. The projection screen of claim 3, wherein each generating kernel substantially satisfies the predetermined scatter profile.

5. The projection screen of claim 4, wherein each generating kernel is operable to minimize point-to-point variation in diffusion.

6. The projection screen of claim 3, wherein the plurality of generating kernels are distributed to optimize viewing from a location in the diffusion locus.

7. The projection screen of claim 3, wherein the plurality of generating kernels satisfy the predetermined scatter profile.

8. The projection screen of claim 7, wherein the plurality of generating kernels is operable to minimize point-to-point variation in diffusion.

9. The projection screen of claim 3, wherein the plurality of generating kernels satisfies a statistical model to minimize double reflections between generating kernels.

10. The projection screen of claim 3, further comprising a dielectric overcoat, the dielectric overcoat distributed over the plurality of generating kernels.

11. The projection screen of claim 3, wherein the plurality of generating kernels are distributed in a substantially regular lattice.

12. The projection screen of claim 11, wherein the substantially regular lattice comprises a hexagonal lattice.

13. The projection screen of claim 11, wherein the plurality of generating kernels are distributed in a tessellation pattern.

14. The projection screen of claim 11, wherein the substantially regular lattice comprises randomized centers.

15. The projection screen of claim 11, wherein at least two of the generating kernels are substantially overlapping.

16. The projection screen of claim 11, wherein at least one of the generating kernels is disposed to pre-correct for an offset resulting from overlapping adjacent generating kernels.

17. The projection screen of claim 1, wherein the diffusion locus is defined by a predetermined reflection angle range.

18. The projection screen of claim 1, wherein substantially all light undergoing more than one reflection is distributed outside of the diffusion locus.

19. The projection screen of claim 1, wherein the diffusion locus includes substantially all viewing locations in an auditorium.

20. The projection screen of claim 1, wherein light reflected to the diffusion locus is of enhanced brightness.

21. The projection screen of claim 1, wherein light reflected to the diffusion locus is substantially uniform.

22. The projection screen of claim 1, wherein light reflected to the diffusion locus is of enhanced contrast.

23. The projection screen of claim 1, wherein light reflected to the diffusion locus satisfies a predetermined gain profile.

24. A method for providing a projection screen, the method comprising:

providing a contoured reflective surface having a predetermined scatter profile, the predetermined scatter profile being operable to reflect incident light from a predetermined incident angle range to within a diffusion locus,

wherein the light reflected from the predetermined incident angle range to within the diffusion locus substantially undergoes no more than one reflection from the contoured reflective surface, further comprising defining the diffusion locus by a region in which reflections within the diffusion locus substantially undergo no more than one reflection on the contoured reflective surface, and wherein light reflected outside of the diffusion locus undergoes one or more reflections on the contoured reflective surface.

25. The method of claim 24, wherein the incident light is polarized light, and wherein light reflected from the predetermined incident angle range to within the diffusion locus maintains the same state of polarization.

26. The method of claim 24, wherein the contoured reflective surface comprises a plurality of generating kernels.

27. The method of claim 26, further comprising satisfying the predetermined scatter profile with each generating kernel.

28. The method of claim 27, further comprising minimizing point-to-point variation in diffusion with each generating kernel.

29. The method of claim 26, further comprising satisfying the predetermined scatter profile with the plurality of generating kernels.

30. The method of claim 29, further comprising minimizing point-to-point variation in diffusion with the plurality of generating kernels.

31. The method of claim 26, further comprising satisfying a statistical model to minimize double reflections between generating kernels with the plurality of generating kernels.

32. The method of claim 26, further comprising distributing the plurality of generating kernels to optimize viewing from a location in the diffusion locus.

33. The method of claim 26, further comprising:

providing a dielectric overcoat; and

distributing the dielectric overcoat over the plurality of generating kernels.

34. The method of claim 26, further comprising distributing the plurality of generating kernels in a substantially regular lattice.

35. The method of claim 34, further comprising randomizing the centers of the substantially regular lattice.

36. The method of claim 34, further comprising overlapping at least two of the generating kernels.

37. The method of claim 26, further comprising distributing the plurality of generating kernels in a substantially hexagonal lattice.

38. The method of claim 26, further comprising distributing the plurality of generating kernels in a tessellation pattern.

39. The method of claim 26, further comprising disposing at least one of the generating kernels to pre-correct for an offset resulting from overlapping adjacent generating kernels.

40. The method of claim 24, further comprising defining the diffusion locus by a predetermined reflection angle range.

41. The method of claim 24, further comprising eliminating substantially all light undergoing multiple reflections from being distributed within the diffusion locus.

42. The method of claim 24, further comprising distributing substantially all light undergoing more than one reflection outside of the diffusion locus.

43. The method of claim 26, further comprising including substantially all viewing locations in an auditorium in the diffusion locus.

44. The method of claim 24, further comprising enhancing the brightness of the light reflected to the diffusion locus.

45. The method of claim 24, further comprising making substantially uniform the light reflected to the diffusion locus.

46. The method of claim 24, further comprising enhancing the contrast of the light reflected to the diffusion locus.

47. The method of claim 24, further comprising satisfying a predetermined gain profile with the light reflected to the diffusion locus.

48. A projection screen, comprising:

a contoured reflective surface having a predetermined scatter profile, the predetermined scatter profile being operable to reflect incident light from a predetermined incident angle range to within a diffusion locus,

wherein the light reflected from the predetermined incident angle range to within the diffusion locus substantially undergoes no more than one reflection from the contoured reflective surface, and

wherein the contoured reflective surface is operable to substantially eliminate light undergoing multiple reflections from being distributed within the diffusion locus.