Anti-reflective polymer constructions and method for producing same

• US 6,926,952 B1
• Filed: 01/13/1998
• Issued: 08/09/2005
• Est. Priority Date: 01/13/1998
• Status: Expired due to Fees

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Weber, Michael F., Ouderkirk, Andrew J.
• Primary Examiner(s): Garrett, Dawn
• Application Number:
  US09/006,379
• Time in Patent Office: 2,765 Days
• Field of Search: 428/212, 428/213, 428/421, 428/480, 428/30, 428/446, 428/483, 359/498
• US Class Current: 428/212
• CPC Class Codes: G02B 1/111 using layers comprising organic materials
• CPC Class Codes: Y10T 428/24942 including components having same physical characteristic in differing degree
• CPC Class Codes: Y10T 428/2495 Thickness [relative or absolute]
• CPC Class Codes: Y10T 428/24967 Absolute thicknesses specified
• CPC Class Codes: Y10T 428/269 including synthetic resin or polymer layer or component
• CPC Class Codes: Y10T 428/3154 Of fluorinated addition polymer from unsaturated monomers
• CPC Class Codes: Y10T 428/31663 As siloxane, silicone or silane
• CPC Class Codes: Y10T 428/31786 Of polyester [e.g., alkyd, etc.]
• CPC Class Codes: Y10T 428/31797 Next to addition polymer from unsaturated monomers
• CPC Class Codes: Y10T 428/31848 Next to cellulosic

Abstract

Articles, including free-standing films, comprising a base comprising a polymer layer having a major surface; and an anti-reflective stack optically coupled to the base that reduces the reflectivity of the base at over a first wavelength range of interest. The anti-reflective stack comprises alternating layers of (i) high index polymer; and (ii) low index polymer. Methods of making such articles are also provided.

Claims

1. An article in the form of a free-standing film comprising:

(a) a base comprising a polymer layer having a major surface; and

(b) an anti-reflective stack optically coupled to said major surface of said base that reduces the reflectivity of said base at said major surface over a wavelength range of interest,

said stack consisting of at least four layers alternating between a layer of a first polymer and a layer of a second polymer, wherein the first polymer is a high index polymer and the second polymer is a low index polymer and the high index polymer has an index of refraction greater than the index of refraction of the base and the low index polymer has an index of refraction less than the index of refraction of the base.

2. An article according to claim 1 wherein the polymer layers of said base and said anti-reflective stack are selected from the group consisting of polymer compositions that are co-extrudable with each other.

3. An article according to claim 1 wherein said anti-reflective stack comprises a low index polymer layer selected from the group consisting of silicone polymers, fluoropolymers, fluoro-chloropolymers, methacrylate polymers, polyester copolymers, and combinations thereof.

4. An article according to claim 1 wherein said anti-reflective stack comprises a low index polymer layer comprising a vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene terpolymer.

5. An article according to claim 1 wherein said anti-reflective stack comprises a high index polymer layer selected from the group consisting of polyesters, polycarbonates, polysulfones, polyethersulfones, and combinations thereof.

6. An article according to claim 1 wherein said anti-reflective stack comprises a birefringent polymer layer having two orthogonal optic axes parallel to the plane of said film.

7. An article according to claim 1 wherein each of the layers of said anti-reflective stack has a thickness no greater than about 1 micrometer.

8. An article according to claim 1 wherein said base comprises a plurality of alternating layers of a first polymer and a second polymer in which said first polymer has a higher index of refraction associated with at least one in-plane axis than adjoining layers of said second polymer.

9. An article according to claim 8 wherein said first polymer comprises polyethylene naphthalate and said second polymer comprises a polyethylene naphthalate copolymer.

10. An article according to claim 1 wherein said base comprises a multilayer reflective polarizer which selectively reflects light of one polarization and transmits light of a second polarization at normal angles of incidence over a second wavelength range of interest.

11. An article according to claim 1 wherein said base comprises a multilayer mirror that reflects light of two orthogonal polarizations at normal angles of incidence over a second wavelength range of interest.

12. An article according to claim 1 wherein said anti-reflective stack comprises a polymer layer having a refractive index that is greater than or equal to the highest refractive index of said base.

13. An article according to claim 1 wherein said base comprises a pair of opposed major surfaces, each of which is optically coupled to an anti-reflective stack.

14. An article in the form of a free-standing film comprising:

(a) a base comprising a polymer layer having a major surface and a multilayer mirror that reflects light of two orthogonal polarizations at normal angles of incidence over a first wavelength range of interest; and

(b) an anti-reflective stack optically coupled to said major surface of said base that reduces the reflectivity of said base at said major surface over a second wavelength range of interest said stack comprising alternating layers of (i) high index polymer; and

(ii) low index polymer;

wherein, the base and stack are formed of different polymers and the high index polymer has an index of refraction greater than an index of refraction of the base and the low index polymer has an index of refraction less than the index of refraction of the base.