Optical film
Optical film is disclosed. The optical film includes a binder, a plurality of particles, and a plurality of interconnected voids. The volume fraction of the plurality of interconnected voids in the optical film is not less than about 20%. The weight ratio of the binder to the plurality of the particles is not less than about 1:2.
1. An optical film comprising:
a low effective index layer having two major surfaces and comprising:
a binder;
a plurality of particles; and
a plurality of interconnected voids comprising surface voids at a major surface of the low effective index layer and interior voids within the interior of the low effective index layer, wherein:
a volume fraction of the plurality of interconnected voids in the optical film is not less than about 20%, and wherein:
a weight ratio of the binder to the plurality of the particles is not less than about 1:2, and
wherein the low effective index layer has a thickness that is not less than about 1 micron.
2. The optical film of claim 1 , wherein at least some of the plurality of particles comprise reactive groups that are chemically bound to the binder.
3. The optical film of claim 1 , wherein at least some of the plurality of particles do not comprise reactive groups.
4. The optical film of claim 1 , wherein the plurality of particles has an average size that is not greater than about 2 microns.
5. The optical film of claim 1 , wherein the plurality of particles has an average size that is not greater than about 1 micron.
6. The optical film of claim 1 , wherein the plurality of particles comprises elongated or spherical particles.
7. The optical film of claim 1 , wherein the plurality of the interconnected voids has an average void size that is not greater than about 2 microns.
8. The optical film of claim 1 , wherein the plurality of the interconnected voids has an average void size that is not greater than about 1 micron.
9. The optical film of claim 1 , wherein the plurality of the interconnected voids has an average void size that is not greater than about 0.7 microns.
10. The optical film of claim 1 , wherein the volume fraction of the plurality of interconnected voids in the low effective index layer is not less than about 30%.
11. The optical film of claim 1 , wherein the volume fraction of the plurality of interconnected voids in the low effective index layer is not less than about 50%.
12. The optical film of claim 1 , wherein the weight ratio of the binder to the plurality of the particles is not less than about 1:1.
13. The optical film of claim 1 , wherein the weight ratio of the binder to the plurality of the particles is not less than about 2:1.
14. The optical film of claim 1 , wherein an effective index of the optical film is not greater than about 1.35.
15. The optical film of claim 1 , wherein an effective index of the optical film is not greater than about 1.25.
16. The optical film of claim 1 , wherein an effective index of the optical film is not greater than about 1.2.
17. The optical film of claim 1 , wherein an effective index of the optical film is not greater than about 1.15.
18. The optical film of claim 1 having an optical haze that is not greater than about 5%.
19. The optical film of claim 1 having an optical haze that is not greater than about 2%.
20. The optical film of claim 1 having an optical haze that is not greater than about 1%.
21. The optical film of claim 1 having an optical haze that is not less than about 50%.
22. The optical film of claim 1 having an optical haze that is not less than about 70%.
23. The optical film of claim 1 having an optical haze that is not less than about 80%.
24. The optical film of claim 1 having an optical haze that is not less than about 90%.
25. The optical film of claim 1 having an optical clarity that is not greater than about 10%.
26. The optical film of claim 1 having an optical clarity that is not greater than about 5%.
27. The optical film of claim 1 having an optical clarity that is not greater than about 2%.
28. The optical film of claim 1 having an optical clarity that is not less than about 50%.
29. The optical film of claim 1 having an optical clarity that is not less than about 70%.
30. The optical film of claim 1 having an optical clarity that is not less than about 90%.
31. The optical film of claim 1 having a diffuse optical reflectance that is not less than about 30%.
32. The optical film of claim 1 having a diffuse optical reflectance that is not less than about 40%.
33. The optical film of claim 1 having a diffuse optical reflectance that is not less than about 50%.
34. The optical film of claim 1 wherein the low effective index layer has a thickness that is not less than about 2 microns.
35. An optical construction comprising:
a substrate; and
the optical film of claim 1 disposed on the substrate.
36. The optical construction of claim 35 , wherein the substrate comprises a release liner.
37. The optical construction of claim 35 further comprising an optical adhesive layer disposed on the optical film of claim 1 .
38. The optical construction of claim 35 further comprising an optical adhesive layer disposed between the substrate and the optical film of claim 1 .
39. The optical film of claim 1 having an optical haze that is not less than about 80%, wherein light scattered by the optical for normally incident light has a luminance L 1 at zero degrees and a luminance L 2 at 10 degrees, L 1 /L 2 not being less than about 10.
40. The optical film of claim 39 , wherein the optical film has an optical haze that is not less than about 90%.
41. The optical film of claim 39 , wherein L 1 /L 2 is not less than about 20.
42. The optical film of claim 39 , wherein L 1 /L 2 is not less than about 50.
43. The optical film of claim 39 , wherein L 1 /L 2 is not less than about 100.
44. The optical film of claim 1 , wherein the interior voids are connected to a major surface via other voids.
45. An optical film comprising:
a low effective index layer having two major surfaces and comprising:
a binder;
a plurality of elongated particles; and
a plurality of interconnected voids comprising surface voids at a major surface of the low effective index layer and interior voids within the interior of the low effective index layer, wherein:
a volume fraction of the plurality of interconnected voids in the low effective index layer is not less than about 20%,
a thickness of the portion of the low effective index layer is not less than about 1 micron, and wherein:
an optical haze of the optical film is not greater than about 1.5%.
46. The optical film of claim 45 , wherein the elongated particles in the plurality of elongated particles have an average aspect ratio that is not less than about 2.
47. The optical film of claim 45 , wherein the elongated particles in the plurality of elongated particles have an average aspect ratio that is not less than about 3.
48. The optical film of claim 45 , wherein the elongated particles in the plurality of elongated particles have an average aspect ratio that is not less than about 4.
49. The optical film of claim 45 , wherein the volume fraction of the plurality of interconnected voids in the low effective index layer is not less than about 40%.
50. The optical film of claim 45 , wherein the volume fraction of the plurality of interconnected voids in the low effective index layer is not less than about 60%.
51. The optical film of claim 45 , wherein the thickness of the low effective index layer is not less than about 1.5 microns.
52. The optical film of claim 45 , wherein the thickness of the portion of the optical film having the plurality of voids is not less than about 2 microns.
53. The optical film of claim 45 , wherein the thickness of the low effective index layer is not less than about 2.5 microns.
54. The optical film of claim 45 , wherein the optical haze of the optical film is not greater than about 1%.
55. The optical film of claim 45 having an effective index of refraction that is not greater than about 1.3.
56. The optical film of claim 45 having an effective index of refraction that is not greater than about 1.25.
57. The optical film of claim 45 having an effective index of refraction that is not greater than about 1.2.
58. The optical film of claim 45 , wherein the voids in the plurality of the interconnected voids have an average size that is not greater than about 50 nm.
59. The optical film of claim 45 , wherein the interior voids are connected to a major surface via other voids.
60. An optical film comprising a low effective index layer having two major surfaces and comprising a plurality of particles coated and interconnected by a binder, the interconnected plurality of particles defining a plurality of interconnected voids comprising surface voids at a major surface of the low effective index layer and interior voids within the interior of the low effective index layer, the interior voids having an average size that is in a range from about 100 nm to about 300 nm, wherein the optical film has:
a thickness of the low effective index layer that is not less than about 1 micron;
an optical haze that is in a range from about 20% to about 70%; and
an optical clarity that is not less than about 80%.
61. The optical film of claim 60 having an optical clarity that is not less than about 90%.
62. The optical film of claim 60 having an optical clarity that is not less than about 95%.
63. The optical film of claim 60 , wherein the interior voids are connected to a major surface via other voids.
64. An optical film comprising:
a low effective index layer having two major surfaces comprising:
a plurality of elongated particles; and
a plurality of voids comprising surface voids at a major surface of the low effective index layer and interior voids within the interior of the low effective index layer, wherein, the optical film has:
an index of refraction that is not greater than about 1.3;
a thickness of the low effective index layer that is not less than about 5 microns; and
an optical haze that is not greater than about 2%.
65. The optical film of claim 64 , wherein the optical film has an index of refraction that is not greater than about 1.2.
66. The optical film of claim 64 , wherein the low effective index layer has a thickness that is not less than about 10 microns.
67. The optical film of claim 64 , wherein the low effective index layer has a thickness that is not less than about 15 microns.
68. The optical film of claim 64 , wherein the interior voids are connected to a major surface via other voids.
69. An optical construction comprising:
a structured surface comprising a plurality of structures, at least some of the structures having a height that is not less than about 10 microns; and
an optical film comprising low effective index layer having two major surfaces and comprising a plurality of elongated particles and a plurality of voids comprising surface voids at a major surface of the low effective index layer and interior voids within the interior of the low effective index layer, the optical film coated on and substantially planarizing the structured surface, wherein the low effective index layer has a thickness that is not less than about 1 micron, the optical film comprising:
an index that is not greater than about 1.2; and
an optical haze that is not greater than about 2%.
70. The optical film of claim 69 , wherein the interior voids are connected to a major surface via other voids.