Polarization preserving front projection screen microstructures

• US 8,004,758 B2
• Filed: 08/10/2009
• Issued: 08/23/2011
• Est. Priority Date: 01/28/2008
• Status: Active Grant

• Current Assignee: RealD Incorporated
• Original Assignee: RealD Incorporated
• Inventors: Sharp, Gary D., Coleman, David A.
• Primary Examiner(s): MAHONEY, CHRISTOPHER E
• Application Number:
  US12/538,648
• Publication Number:
  US 20100188746A1
• Time in Patent Office: 743 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 contoured reflective microstructure, comprising:

a substrate; and

at least one generating kernel distributed over at least one surface of the substrate, the at least one generating kernel operable to reflect polarized light to substantially all viewing locations, wherein the at least one generating kernel has a topographical shape operable to substantially eliminate secondary reflections of light within a predetermined incident angle range.

2. The contoured reflective microstructure of claim 1, wherein the microstructure is operable to reflect light to substantially all viewing locations, the light incident on the generating kernel coming from within a predetermined incident angle range.

3. The contoured reflective microstructure of claim 2, wherein the incident light is polarized light and maintains the same state of polarization before and after reflection from the microstructure.

4. The contoured reflective microstructure of claim 1, wherein the microstructure has a profile that satisfies a statistical model to minimize double reflections from light incident at the predetermined incident angle range.

5. The contoured reflective microstructure of claim 1, wherein the microstructure comprises a plurality of generating kernels.

6. The contoured reflective microstructure of claim 5, wherein the plurality of generating kernels are distributed in a substantially regular lattice.

7. The contoured reflective microstructure of claim 5, wherein the plurality of generating kernels are distributed in a tessellation pattern.

8. The contoured reflective microstructure of claim 5, wherein two of the at least one generating kernels are substantially overlapping.

9. The contoured reflective microstructure of claim 5, wherein at least one of the generating kernels is disposed to pre-correct for an offset resulting from overlapping adjacent generating kernels.

10. The contoured reflective microstructure of claim 1, wherein each of the at least one generating kernels satisfies a predetermined statistical model such that point-to-point variation in reflection is substantially eliminated.

11. A contoured reflective microstructure for a projection screen, comprising:

a substrate; and

at least one generating kernel disposed on a surface of the substrate, the at least one generating kernel operable to reflect polarized light to substantially all viewing locations, the polarized light being projected toward the microstructure from within a predetermined incident angle range;

wherein the at least one generating kernel has a topographical shape operable to substantially eliminate secondary reflections of the polarized light incident from within the predetermined incident angle range to the viewing locations, and wherein the polarized light maintains substantially the same state of polarization before and after reflection from the microstructure.

12. The contoured reflective microstructure of claim 11, wherein the microstructure has a profile that satisfies a statistical model to minimize double reflections from light incident within the predetermined incident angle range.

13. The contoured reflective microstructure of claim 11, wherein the microstructure comprises a plurality of generating kernels.

14. The contoured reflective microstructure of claim 13, wherein the plurality of generating kernels are distributed in a substantially regular lattice.

15. A contoured reflective microstructure for a projection screen, comprising:

a substrate; and

a plurality of generating kernels distributed over at least one surface of the substrate, wherein each of the plurality of generating kernels has a topographical shape operable to substantially eliminate secondary reflections of light within a predetermined incident angle range, and

wherein at least two of the plurality of generating kernels are overlapping and at least one of the overlapping generating kernels is disposed to pre-correct for an offset resulting from an overlapping adjacent generating kernel.

16. The contoured reflective microstructure of claim 15, wherein a subset of the plurality of generating kernels satisfies a predetermined statistical model such that point-to-point variation in reflection is substantially minimized.

17. The contoured reflective microstructure of claim 15, wherein the plurality of generating kernels are distributed in a substantially regular lattice.

18. The contoured reflective microstructure of claim 15, wherein the plurality of generating kernels are distributed in a tessellation pattern.

19. The contoured reflective microstructure of claim 15, wherein each of the at least one generating kernels satisfies a predetermined statistical model such that point-to-point variation in reflection is substantially eliminated.

20. The contoured reflective microstructure of claim 15, wherein the microstructure is substantially ergodic.