Reflective polarizers containing polymer fibers

• US 20060193577A1
• Filed: 02/28/2005
• Published: 08/31/2006
• Est. Priority Date: 02/28/2005
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Ouderkirk, Andrew J., Thunhorst, Kristin L., Fleming, Patrick R., Ruff, Andrew T., North, Diane, Allen, Richard C.
• Granted Patent: US 7,356,229 B2
• Time in Patent Office: Days
• US Class Current: 385/115
• CPC Class Codes: G02B 5/3008 comprising dielectric particles, e.g. birefringent crystals embedded in a matrix

Abstract

A polarizer is formed with an arrangement of polymer fibers substantially parallel within a polymer matrix. The polymer fibers are formed of at least first and second polymer materials. At least one of the polymer matrix and the first and second polymer materials is birefringent, and provides a birefringent interface with the adjacent material. Light is reflected and/or scattered at the birefringent interfaces with sensitivity to the polarization of the light. In some embodiments, the polymer fibers are formed as composite fibers, having a plurality of scattering polymer fibers disposed within a filler to form the composite fiber. In other embodiments, the polymer fiber is a multilayered polymer fiber. The polymer fibers may be arranged within the polymer matrix as part of a fiber weave.

Claims

1. An optical body, comprising:

a polymer matrix; and

a plurality of polymer fibers disposed within the polymer matrix, wherein at least one of the polymer fibers comprises multiple birefringent interfaces for reflecting light, the birefringent interfaces being formed between a first polymer material and a second polymer material, at least one of the first and second polymer materials being birefringent, the birefringent interfaces being internal to the at least one of the polymer fibers and are elongated along an axis of the at least one polymer fiber, the polymer fibers being oriented substantially parallel to a first axis, a refractive index difference at the birefringent interfaces for light polarized parallel to the first axis being different from a refractive index difference at the birefringent interfaces for light polarized parallel to a second axis, the second axis being orthogonal to the first axis.

2. An optical body as recited in claim 1, wherein the second polymer material is an optically isotropic polymer material.

3. An optical body as recited in claim 1, wherein the polymer fibers comprise at least one composite fiber, the at least one composite fiber comprising a plurality of scattering polymer fibers formed of the first polymer material embedded within the second polymer material.

4. An optical body as recited in claim 3, wherein at least some of the scattering polymer fibers are arranged in a regular pattern in a cross-section through the composite fiber.

5. An optical body as recited in claim 3, wherein at least some of the scattering polymer fibers are arranged irregularly in a cross-section through the composite fiber.

6. An optical body as recited in claim 3, wherein at least one of the scattering fibers comprises a disperse phase of a third polymer material in a continuous phase of the second polymer material.

7. An optical body as recited in claim 1, wherein the polymer fibers comprise polymer fiber yarn.

8. An optical body as recited in claim 1, wherein the polymer fibers comprise alternating layers of the first and second polymer materials.

9. An optical body as recited in claim 8, wherein the layers of the first and second polymer materials are substantially planar.

10. An optical body as recited in claim 8, wherein the layers of the alternating first and second polymer materials are arranged concentrically.

11. An optical body as recited in claim 10, wherein the layers of the alternating first and second polymer materials are circularly concentric.

12. An optical body as recited in claim 8, wherein the layers of the alternating first and second polymer materials are surrounded by a cover layer.

13. An optical body as recited in claim 12, wherein the cover layer is formed of one of the first and second polymer materials.

14. An optical body as recited in claim 8, wherein the birefringent interfaces formed by the layers of the alternating first and second polymer materials are oriented, in different fibers, in random directions.

15. An optical body as recited in claim 8, wherein the birefringent interfaces formed by the layers of the alternating first and second polymer materials are oriented, in different fibers, in selected directions.

16. An optical body as recited in claim 1, wherein the polymer fibers comprise at least one disperse phase fiber, the disperse phase fiber comprising a disperse phase of the first polymer material in a continuous phase of the second polymer material.

17. An optical body as recited in claim 1, wherein at least one of the polymer fibers has a cover layer.

18. An optical body as recited in claim 1, further comprising a fiber weave disposed within the polymer matrix, the fiber weave comprising the plurality of polymer fibers.

19. An optical body as recited in claim 18, wherein the plurality of polymer fibers comprise one of the warp and the weft of the fiber weave.

20. An optical body as recited in claim 19, wherein the other of the warp and the weft of the fiber weave comprises optically isotropic polymer fibers.

21. An optical body as recited in claim 19, wherein the other of the warp and the weft of the fiber weave comprises optically isotropic natural fibers.

22. An optical body as recited in claim 19, wherein the other of the warp and the weft of the fiber weave comprises at least one of glass fibers, glass-ceramic fibers and ceramic fibers.

23. An optical body as recited in claim 19, wherein the other of the warp and the weft of the fiber weave comprises isotropic fibers having a refractive index substantially similar to the refractive index of the polymer matrix.

24. An optical body as recited in claim 18, wherein the polymer fibers in the fiber weave are substantially straight.

25. An optical body as recited in claim 1, further comprising a non-woven disposed within the polymer matrix, the non-woven comprising the plurality of polymer fibers.

26. An optical body as recited in claim 1, further comprising a chopped fiber mat disposed within the polymer matrix, the chopped fiber mat comprising the plurality of polymer fibers.

27. An optical body as recited in claim 1, further comprising chopped fiber disposed within the polymer matrix, the chopped fiber comprising the plurality of polymer fibers.

28. An optical body as recited in claim 1, wherein the polymer matrix is formed as a layer containing the plurality of polymer fibers, the layer having substantially flat and parallel surfaces.

29. An optical body as recited in claim 1, wherein the polymer matrix is formed as a layer having at least one structured surface.

30. An optical body as recited in claim 29, wherein the at least one structured surface provides optical power to light transmitted through the body.

31. An optical body as recited in claim 29, wherein the at least one structured surface comprises an array of prismatic structures.

32. An optical body as recited in claim 1, wherein the polymer matrix has a first refractive index and the first polymer material is birefringent, having an ordinary refractive index substantially the same as the first refractive index for light polarized orthogonally to the first axis and has an extraordinary refractive index different from the first refractive index for light polarized parallel to the first axis.

33. An optical body as recited in claim 32, wherein the extraordinary refractive index is greater than the ordinary refractive index.

34. An optical body, comprising:

an optical material having a first refractive index, n_x, along a first axis and a second refractive index, n_y, along a second axis perpendicular to the first axis; and

elongated polymer fibers disposed within the optical material parallel to the first axis, the polymer fibers comprising a first birefringent material elongated along the first axis and having a refractive index, n_1x, along the first axis and a refractive index n_1y along the second axis, where n_{1x i}s different from n_1y, the elongated polymer fibers comprising a second material elongated along the first axis and having a refractive index n_2x along the first axis and a refractive index n_2y along the second axis, the optical body scattering incident light polarized along the first axis differently than incident light polarized along the second axis.

35. A body as recited in claim 34, wherein n_x is substantially equal to n_y.

36. A body as recited in claim 34, wherein n_2x is substantially equal to n_2y.

37. A body as recited in claim 34, wherein n_x is substantially equal to n_2x.

38. A body as recited in claim 34, wherein the light is scattered at least within the elongated polymer fibers at interfaces between the first birefringent material and the second material.

39. An optical body, comprising:

a polymer matrix; and

a plurality of polymer fibers disposed within the polymer matrix, wherein at least one of the polymer fibers comprises multiple, elongated birefringent scattering means for scattering incident light, the scattering means being provided internally within the fibers.