Light-collimating film
Light-collimating films as well as other microstructured film articles are described that comprise a (e.g. UV) cured light transmissive film comprising the reaction product of a polymerizable resin composition. Polymerizable resin compositions are also described that comprise aliphatic urethane(meth)acrylate oligomer(s), bisphenol-A ethoxylated diacrylate(s), and a crosslinker having at least three (meth)acrylate groups.
1. A light-collimating film comprising a cured transparent film having a plurality light-absorbing elements wherein the cured transparent film is the reaction product of a polymerizable resin comprising first and second polymerizable components selected from an aliphatic urethane diacrylate oligomer and a bisphenol-A ethoxylated diacrylate or bisphenol-A ethoxylated diacrylates; and a crosslinker having at least three (meth) acrylate groups; wherein a homopolymer of the second polymerizable component has an elastic tensile modulus as measured according to ASTM D5026-01 of less than 1×10 8 Pa at 25° C. and a homopolymer of the first polymerizable component has a modulus at least 5×10 7 Pa at 25° C. greater than the homopolymer of the second polymerizable component.
2. The light-collimating film of claim 1 wherein the first polymerizable component has a viscosity of at least about 5000 cps at 60° C. and the second polymerizable component has a viscosity no greater than about 75% of the viscosity of the first polymerizable component.
3. The light-collimating film of claim 2 wherein the second polymerizable component has a viscosity of no greater than 50% of the viscosity of the first polymerizable component.
4. The light-collimating film of claim 1 the first polymerizable component is present at a weight ratio that ranges from 4:1 to 1:4 with respect to the second polymerizable component.
5. The light-collimating film of claim 1 wherein the combination of first and second polymerizable components are present in an amount that ranges from about 50 wt-% to about 90% wt-% of the total polymerizable resin composition.
6. The light-collimating film of claim 1 wherein the light absorbing elements comprises a cured polymerizable resin including a light absorbing colorant.
7. The light-collimating film of claim 6 wherein the cured transparent film and the light absorbing elements each have a refractive index that differ by an amount ranging from 0 to 0.002.
8. The light-collimating film of claim 1 wherein the cured transparent film comprises microstructures between the light absorbing elements and the microstructures have an average height, D, an average width at its widest portion, W, and D/W is at least 1.75.
9. The light-collimating film of claim 1 wherein the cured transparent film comprises microstructures between the light absorbing elements, the microstructures having an included wall angle of less than 6 degrees.
10. The light-collimating film of claim 9 wherein the microstructures have an included wall angle of less than 4 degrees.
11. The light-collimating film of claim 1 wherein the light-collimating film has a transmission at an incident angle of 0° of at least 56%.
12. The light-collimating film of claim 1 wherein the polymerizable resin has a viscosity of less than 50,000 cps at 25° C.
13. The light-collimating film of claim 1 wherein the cured transparent film is disposed on a polyester film.
14. The light-collimating film of claim 13 wherein the light-collimating film has a stiffness of at least 65 N/mm.
15. The light-collimating film of claim 13 wherein the light-collimating film has a thickness of less than 535 microns and a stiffness of at least 50 N/mm.
16. A light-collimating film comprising a cured transparent film having a plurality of light absorbing elements wherein the cured transparent film is the reaction product of a polymerizable resin having a viscosity of less than 50,000 cps at 25° C. and the cured transparent film comprises microstructures between the light absorbing elements, the microstructures having an included wall angle of less than 6 degrees.
17. A light-collimating film comprising a cured transparent film having a plurality of light absorbing elements wherein the cured transparent film is disposed on a polyester film and the cured transparent film comprises microstructures between the light absorbing elements, the microstructures having an included wall angle of less than 6 degrees and the light-collimating film having a stiffness of at least 65 N/mm or a thickness of less than 535 microns and a stiffness of at least 50 N/mm.
18. The light-collimating film of claim 16 wherein the microstructures have an average height, D, an average width at its widest portion, W, and D/W is at least 1.75.
19. The light-collimating film of claim 16 wherein the microstructures have an included wall angle of less than 4 degrees.
20. The light-collimating film of claim 16 wherein the microstructures comprise the reaction product of a polymerizable resin comprising a first and second polymerizable components selected from difunctional (meth)acrylate monomers, difunctional (meth)acrylate oligomers, and mixtures thereof and a crosslinker having at least three (meth) acrylate groups.
21. The light-collimating film of claim 20 wherein the first polymerizable component and second polymerizable components are present in an amount that ranges from about 50 wt-% to about 90% wt-% of the total polymerizable resin composition.
22. The light-collimating film of claim 20 wherein the first polymerizable component comprises an aliphatic urethane diacrylate oligomer and the second polymerizable component comprises a bisphenol-A ethoxylated diacrylate.
23. The light-collimating film of claim 17 wherein the microstructures have an average height, D, an average width at its widest portion, W, and D/W is at least 1.75.
24. The light-collimating film of claim 17 wherein the microstructures have an included wall angle of less than 4 degrees.
25. The light-collimating film of claim 17 wherein the microstructures comprise the reaction product of a polymerizable resin comprising a first and second polymerizable components selected from difunctional (meth)acrylate monomers, difunctional (meth)acrylate oligomers, and mixtures thereof and a crosslinker having at least three (meth) acrylate groups.
26. The light-collimating film of claim 25 wherein the first polymerizable component and second polymerizable components are present in an amount that ranges from about 50 wt-% to about 90% wt-% of the total polymerizable resin composition.
27. The light-collimating film of claim 25 wherein the first polymerizable component comprises an aliphatic urethane diacrylate oligomer and the second polymerizable component comprises a bisphenol-A ethoxylated diacrylate.