Polarization preserving front projection screen material

• US 8,072,681 B2
• Filed: 08/10/2009
• Issued: 12/06/2011
• 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
• Application Number:
  US12/538,642
• Publication Number:
  US 20090297797A1
• Time in Patent Office: 848 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. Roll stock for a projection screen, comprising:

a roll of projection screen material having a first and second side;

a plurality of reflective microstructures distributed over the first side of the projection screen material, the reflective microstructures distributed according to a predetermined scatter profile operable to reflect incident light from a predetermined incident angle range to within a diffusion locus, wherein light reflected from the predetermined incident angle range to within the diffusion locus substantially undergoes no more than one reflection from the first side of the projection screen material, wherein the plurality of reflective microstructures distributed over the first side of the projection screen material comprises a spatially homogenous statistical distribution of reflective microstructures.

2. The roll stock of claim 1, wherein the microstructures are created using UV embossing techniques.

3. The roll stock of claim 1, wherein the microstructures are created using bead blasting.

4. The roll stock 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.

5. The roll stock of claim 1, wherein each microstructure of the plurality of microstructures comprises at least one generating kernel.

6. The roll stock of claim 5, wherein each generating kernel substantially satisfies the predetermined scatter profile.

7. The roll stock of claim 1, wherein each microstructure satisfies the predetermined scatter profile.

8. The roll stock of claim 1, wherein the plurality of reflective microstructures are distributed in a substantially regular lattice.

9. The roll stock of claim 8, wherein the substantially regular lattice comprises a hexagonal lattice.

10. The roll stock of claim 1, wherein the plurality of reflective microstructures are distributed in a tessellation pattern.

11. A method for making a projection screen from roll stock, the method comprising:

providing a roll of projection screen material having a first and second side; and

distributing a plurality of reflective microstructures over the first side of the projection screen material according to a predetermined scatter profile operable to reflect incident light from a predetermined incident angle range to within a diffusion locus, wherein light reflected from the predetermined incident angle range to within the diffusion locus substantially undergoes no more than one reflection from the first side of the projection screen material, wherein the substrate and plurality of reflective microstructures comprise a roll stock of projection screen forming material, wherein the plurality of reflective microstructures distributed over the first side of the projection screen material comprises a spatially homogenous statistical distribution of reflective microstructures.

12. The method of claim 11, further comprising applying a dielectric coating to the projection screen material.

13. The method of claim 11, further comprising:

cutting individual sheets of the roll stock of projection screen material;

joining the individual sheets of the roll stock of projection screen material together; and

applying a dielectric coating over the joined individual sheets of the roll stock of projection screen material.

14. The method of claim 13, wherein the joining of the individual sheets of the roll stock of projection screen material is performed such that joins between the individual sheets are substantially not noticeable from viewing locations.

15. The method of claim 11, further comprising:

cutting strips of the roll stock of projection screen material;

positioning the strips in a vertical orientation; and

connecting the strips together.

16. The method of claim 15, wherein the strips are connected together using a system of rollers.

17. The method of claim 15, wherein the strips are connected using adhesives.

18. The method of claim 15, wherein the strips are connected using one of chemical solvents or doped solvents.

19. The method of claim 15, wherein the strips are connected using a welding process.

20. The method of claim 15, further comprising:

providing a secondary backing sheet; and

attaching the secondary backing sheet to the back of the connected strips of the roll stock of projection screen material.

21. Roll stock for a projection screen, comprising:

a roll of projection screen material having a first and second side; and

a plurality of reflective microstructures distributed over the first side of the roll stock, the reflective microstructures comprising at least one generating kernel, 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, wherein the plurality of reflective microstructures distributed over the first side of the projection screen material comprises a spatially homogenous statistical distribution of reflective microstructures.

22. The roll stock for a projection screen of claim 21, wherein the generating kernel 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.