Polarization preserving projection screen with engineered particle and method for making same

• US 20110149389A1
• Filed: 12/22/2010
• Published: 06/23/2011
• Est. Priority Date: 12/22/2009
• Status: Active Grant

• Current Assignee: RealD Incorporated
• Original Assignee: RealD Incorporated, Wavefront Technology, Inc.
• Inventors: Petersen, Joel, Lewandowski, Raymond Jacob, Rich, Christopher, Sharp, Gary D., Coleman, David A.
• Granted Patent: US 8,194,315 B2
• Time in Patent Office: Days
• US Class Current: 359/452
• CPC Class Codes: B29D 11/0074 Production of other optical elements not provided for in B29D11/00009- B29D11/0073
• CPC Class Codes: G03B 21/604 Polarised screens
• CPC Class Codes: Y10T 156/1052 with cutting, punching, tearing or severing

Abstract

Polarization preserving projection screens provide optimum polarization preservation for 3D viewing. The projection screens additionally provide improved light control for enhanced brightness, uniformity, and contrast for both 2D and 3D systems. Generally, the disclosed method for providing a projection screen comprises embossing at least a first side of a first substrate to produce an optically functional material and then cutting the optically functional material into pieces to produce a plurality of engineered particles. The plurality of engineered particles may then be deposited on a second substrate to produce a substantially homogeneous optical appearance of the projection screen.

Claims

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

embossing at least a first side of a first substrate to produce an optically functional material;

cutting the optically functional material into pieces to produce a plurality of engineered particles; and

depositing the plurality of engineered particles on a second substrate to produce a substantially homogeneous optical appearance of the projection screen.

2. The method of claim 1, further comprising embossing a second side of the first substrate to produce the optically functional material.

3. The method of claim 2, wherein the embossing on the first and second side of the first substrate are substantially similar patterns.

4. The method of claim 2, wherein the embossing on the first and second side of the first substrate are different patterns.

5. The method of claim 1, wherein the embossing further comprises holding a predetermined tolerance, further wherein the predetermined tolerance is based on at least a difference between long-range statistics and ensemble statistics of the projection screen.

6. The method of claim 1, wherein depositing the plurality of engineered particles on the second substrate provides a surface on the second substrate that substantially approximates the statistics of the embossed first substrate.

7. The method of claim 1, further comprising distributing a reflective coating on at least a first side of the first substrate.

8. The method of claim 7, wherein the reflective coating is substantially conformal to the embossed surface of the first substrate.

9. The method of claim 7, further comprising distributing an optical coating on at least the first side of the first substrate and adjacent to the reflective coating.

10. The method of claim 9, wherein the optical coating is a dielectric coating operable to passivate the reflective coating.

11. The method of claim 7, wherein the reflective coating is aluminum.

12. The method of claim 1, further comprising combining the plurality of engineered particles with a binder to produce a coating.

13. The method of claim 12, further comprising matching the refractive index of the first substrate and the binder.

14. The method of claim 1, wherein cutting the optically functional material, further comprises producing approximately vertical side walls of the plurality of engineered particles, wherein the side walls are substantially smooth.

15. The method of claim 1, wherein cutting the optically functional material further comprises producing approximately hexagonal engineered particles.

16. The method of claim 15, wherein the approximately hexagonal engineered particles are one millimeter in size.

17. The method of claim 1, wherein cutting the optically functional material further comprises producing similarly sized engineered particles.

18. The method of claim 17, wherein the similarly sized engineered particles are approximately hexagonal in shape.

19. The method of claim 1, wherein the embossing produces an embossed layer with features wherein the mean feature size is a maximum in plane size of approximately ten microns.

20. The method of claim 1, wherein depositing the plurality of engineered particles on the second substrate further comprises producing a substantially continuous metal surface at an optical interface with a substantially minimal resin overcoat.

21. The method of claim 1, wherein depositing the plurality of engineered particles on the second substrate substantially minimizes the effect of particle tipping statistics on the scatter profile.

22. The method of claim 1, wherein the second substrate has an adhesive layer.

23. The method of claim 22, wherein the adhesive layer is a pressure sensitive adhesive.

24. The method of claim 1, wherein the second substrate is an irregularly shaped surface.

25. The method of claim 24, wherein the irregularly shaped surface is a dome.

26. The method of claim 12, wherein distributing the coating is operable to substantially minimize the role of particle tipping statistics on the scatter profile of the coating.

27. The method of claim 1, wherein distributing the coating further comprises producing a dense stack of the individual engineered particles lying substantially in-plane at the surface of the coating.

28. The method of claim 1, further comprising maintaining a high particle-to-feature ratio for the individual engineered particles of the plurality of engineered particles.

29. The method of claim 1, wherein the first substrate has a thickness in the range of five to fifty microns.

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

embossing at least a first side of a first substrate;

embossing at least a first side of a second substrate;

laminating the first substrate and the second substrate together to produce an optically functional material;

cutting the optically functional material into pieces to produce engineered particles; and

depositing the engineered particles on a third substrate to produce a substantially homogeneous optical appearance of the projection screen.

31. The method of claim 30, wherein the embossing on the first of the first substrate and the second side of the second substrate produces substantially similar patterns.

32. The method of claim 30, wherein the embossing further comprises holding a predetermined tolerance, further wherein the predetermined tolerance is based on at least a difference between long-range statistics and ensemble statistics.

33. The method of claim 30, wherein depositing the plurality of engineered particles provides a surface that substantially approximates the statistics of the embossed substrate.

34. The method of claim 30, further comprising distributing a reflective coating on at least a first side of the first substrate.

35. The method of claim 34, wherein the reflective coating is substantially conformal to the embossed surface of the first substrate.

36. The method of claim 34, further comprising distributing an optical coating over the reflective coating.

37. The method of claim 36, wherein the optical coating is a dielectric coating operable to passivate the reflective coating.

38. The method of claim 34, wherein the reflective coating is aluminum.

39. The method of claim 30, further comprising combining the plurality of engineered particles with a binder to produce a coating.

40. The method of claim 39, further comprising matching the refractive index of the first substrate and the binder.

41. The method of claim 30, wherein cutting the optically functional material, further comprises producing approximately vertical side walls of the plurality of engineered particles, wherein the side walls are substantially smooth.

42. The method of claim 30, wherein cutting the optically functional material further comprises producing approximately hexagonal engineered particles.

43. The method of claim 42, wherein the approximately hexagonal engineered particles are 1 millimeter in size.

44. The method of claim 30, wherein the embossing produces an embossed layer with features wherein the mean feature size is a maximum size of 10 microns.

45. The method of claim 30, wherein depositing the plurality of engineered particles on the second substrate further comprises producing a substantially continuous metal surface at an optical interface with a substantially minimal resin overcoat.

46. The method of claim 30, wherein depositing the plurality of engineered particles on the second substrate substantially minimizes the effect of particle tipping statistics on the scatter profile.

47. The method of claim 30, wherein the second substrate has an adhesive layer.

48. The method of claim 47, wherein the adhesive layer is a pressure sensitive adhesive.

49. The method of claim 30, wherein the second substrate is an irregularly shaped surface.

50. The method of claim 30, wherein the first and second substrate have a thickness range of 5 to 50 microns.

51. A projection screen with a substantially homogeneous appearance, wherein the substantially homogeneous appearance is achieved through web shuffling, the projection screen comprising:

a first substrate; and

a coating adjacent to the first substrate, the coating comprising a plurality of engineered particles produced by cutting an optically functional material into pieces, wherein the plurality of engineered particles are operable to primarily determine the scattering behavior of light.

52. The projection screen of claim 51, wherein a first side of the optically functional material is embossed.

53. The projection screen of claim 52, wherein a second side of the optically functional material is embossed.

54. The projection screen of claim 51, wherein the coating further comprises a surface operable to decouple the scatter profile from the polarization contrast ratio of the projection screen.

55. The projection screen of claim 51, wherein the plurality of engineered particles are within a predetermined size range.

56. The projection screen of claim 51, further comprising a fluid, wherein the fluid is combined with the plurality of engineered particles to produce the coating.

57. The projection screen of claim 51, wherein the optically functional material further comprises a second substrate has a thickness in the range of five to fifty microns.

58. A projection system comprising:

a projection screen with a substantially homogeneous appearance, wherein the substantially homogeneous appearance is achieved through web shuffling, the projection screen comprising a substrate and a coating adjacent to the substrate, the coating comprising engineered particles produced by cutting an optically functional material into pieces; and

a light projection system directing light in the direction of the projection screen.