Antireflective films comprising microstructured surface

• US 9,383,482 B2
• Filed: 05/03/2011
• Issued: 07/05/2016
• Est. Priority Date: 05/07/2010
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Walker, Christopher B. Jr., Tebow, Christopher P., Pham, Tri D., Kong, Steven H., Aronson, Joseph T., Lindstrom, Kyle J., Gerlach, Michael K., Toy, Michelle L., McKenzie, Taun L., Renstrom, Anthony M., Yapel, Robert A., Johnson, Mitchell A. F.
• Primary Examiner(s): Won, Bumsuk
• Assistant Examiner(s): Madonna, Jeffrey
• Application Number:
  US13/639,902
• Publication Number:
  US 20130038939A1
• Time in Patent Office: 1,890 Days
• Field of Search: 359577-590, 359/599, 359601-615
• US Class Current: 1/1
• CPC Class Codes: G02B 1/118 having sub-optical wavelength surface structures designed to provide an enhanced transmittance, e.g. moth-eye structures
• CPC Class Codes: G02B 5/0242 by means of dispersed particles

Abstract

The present invention concerns antireflective films comprising a high refractive index layer (60) and low refractive index layer (80) disposed on the high refractive index layer. The antireflective films have a microstructured surface (70) that can be derived from a microreplicated tool.

Claims

1. An antireflective film comprising a high refractive index layer and a low refractive index surface layer disposed on the high refractive index layer;

wherein the low refractive index layer comprises a plurality of microstructures having a complement cumulative slope magnitude distribution such that at least 30% have a slope magnitude of at least 0.7 degrees, at least 25% have a slope magnitude less than 1.3 degrees, wherein the microstructures comprise peaks having a mean equivalent circular diameter of at least 5 microns and less than 30 microns and the antireflective film is free of microstructures comprising embedded matte particles, the embedded matte particles having a particle size greater than 0.25 microns.

2. The antireflective film of claim 1 wherein at least 30% of the microstructures have a slope magnitude of less than 1.3 degrees.

3. The antireflective film of claim 1 wherein at least 35% of the microstructures have a slope magnitude of less than 1.3 degrees.

4. The antireflective film of claim 1 wherein at least 40% of the microstructures have a slope magnitude of less than 1.3 degrees.

5. The antireflective film of claim 1 wherein less than 15% of the microstructures have a slope magnitude of 4.1 degrees or greater.

6. The antireflective film of claim 1 wherein less than 5% of the microstructures have a slope magnitude of 4.1 degrees or greater.

7. The antireflective film of claim 1 wherein at least 75% of the microstructures have a slope magnitude of at least 0.3 degrees.

8. The antireflective film of claim 1 wherein the film has an average maximum surface height (Rz) of less than 1.20 microns.

9. The antireflective film of claim 1 wherein the antireflective film has a clarity of at least 70%.

10. The antireflective film of claim 1 wherein the antireflective film has a haze of no greater than 10%.

11. The antireflective film of claim 1 wherein the antireflective film has a haze ranging from 1% to 10%.

12. The antireflective film of claim 1 wherein the antireflective film has an average photopic reflection of less than 2% at a wavelength of 550 nm.

13. The antireflective film of claim 1 wherein the high refractive index layer comprises the reaction product of a polymerizable resin composition having a refractive index of at least 1.60.

14. The antireflective film of claim 13 wherein the polymerizable resin composition comprises nanoparticles having a refractive index of at least 1.60.

15. The antireflective film of claim 14 wherein the nanoparticles comprise zirconia.

16. The antireflective film of claim 1 wherein the low refractive index layer comprises a free-radically polymerizable fluorinated polymer that comprises polymeric species having a hyperbranched structure.

17. The antireflective film of claim 16 wherein the free-radically polymerizable fluorinated polymer comprises the reaction product of i) at least one multi-functional free-radically polymerizable material having a fluorine content of at least 25 wt-%, and ii) optionally at least one multi-functional free-radically polymerizable material having a fluorine content ranging from 0 to less than 25 wt-%, wherein the total amount of multi-functional materials is at least about 25 wt-% based on wt-% solids of the polymerizable organic composition.

18. The antireflective film of claim 1 wherein the low refractive index layer comprises a free-radically polymerizable fluorinated polymer that comprises at least two constituent monomers selected from tetrafluoroethylene, vinylidene fluoride, and hexafluoropropylene, and has reactive functionality from at least one halogen containing cure site monomer.

19. The antireflective film of claim 1 wherein the low refractive index layer comprises the reaction product of a first free-racially polymerizable fluorinated polymer comprising polymeric species having a hyperbranched structure;

and

a second free-radically polymerizable fluorinated polymer that comprises at least two constituent monomers selected from tetrafluoroethylene, vinylidene fluoride, and hexafluoropropylene, and has reactive functionality from at least one halogen containing cure site monomer.

20. An antireflective film comprising a high refractive index layer and a low refractive index surface layer disposed on the high refractive index layer;

wherein the low refractive index layer comprises a plurality of microstructures having a complement cumulative slope magnitude distribution such that at least 25% have a slope magnitude of at least 0.7 degrees, at least 40% have a slope magnitude less than 1.3 degrees, wherein the microstructures comprise peaks having a mean equivalent circular diameter of at least 5 microns and less than 30 microns and no greater than 50% of the microstructures comprise embedded matte particles, the embedded matte particles having a particle size greater than 0.25 microns.