Dichroic polarizing film and optical polarizer containing the film

• US 6,335,051 B1
• Filed: 06/27/2000
• Issued: 01/01/2002
• Est. Priority Date: 01/13/1998
• Status: Expired due to Term

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Kausch, William L., Merrill, William W., Williams, Brian H.
• Primary Examiner(s): Yoon, Tae H.
• Application Number:
  US09/604,491
• Time in Patent Office: 553 Days
• Field of Search: 252/585, 359/584, 359/587, 428/500, 428/910, 427/58, 427/163.1
• US Class Current: 427/163.1
• CPC Class Codes: C08J 2329/04 Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids
• CPC Class Codes: C08J 5/18 Manufacture of films or sheets
• CPC Class Codes: C08K 3/02 Elements
• CPC Class Codes: C08L 2666/04 Macromolecular compounds according to groups C08L7/00 - C08L49/00, or C08L55/00 - C08L57/00; Derivatives thereof
• CPC Class Codes: C08L 2666/18 Polyesters or polycarbonates according to C08L67/00 - C08L69/00; Derivatives thereof
• CPC Class Codes: C08L 29/04 Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids
• CPC Class Codes: C08L 39/06 Homopolymers or copolymers of N-vinyl-pyrrolidones
• CPC Class Codes: C08L 67/00 Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain of polyester-amides C08L77/12; of polyester-imides C08L79/08; Compositions of derivatives of such polymers
• CPC Class Codes: C09K 2323/031 Polarizer or dye
• CPC Class Codes: G02B 5/3033 in the form of a thin sheet or foil, e.g. Polaroid
• CPC Class Codes: G02B 5/305 including organic materials, e.g. polymeric layers
• CPC Class Codes: Y10S 428/91 Product with molecular orientation
• CPC Class Codes: Y10T 428/249921 Web or sheet containing structurally defined element or component
• CPC Class Codes: Y10T 428/31855 Of addition polymer from unsaturated monomers

Abstract

A dichroic polarizing film is made, for example, by, first combining polyvinyl alcohol and a second polymer, such as, polyvinyl pyrrolidone or a sulfonated polyester, in a solvent. The ratio of polyvinyl alcohol to second polymer is between about 5:1 to 100:1 by weight. The film is coated on a substrate, dried, and then stretched to orient at least a portion of the film. The film incorporates a dichroic dye material, such as iodine, to form a dichroic polarizer. This polarizer may be used in conjunction with a multilayer optical film, such as a reflective polarizer, to form an optical polarizer. The multilayer optical film may contain two or more sets of polyester films, where at least one of the sets is birefringent and orientable by stretching. The polyvinyl alcohol/second polymer film and the multilayer optical film may be simultaneously stretched to orient both polymer films.

Claims

1. An optical device, comprising:

a substrate;

an oriented polymeric film disposed on the substrate, the polymeric film comprising polyvinyl alcohol and a water-soluble or water-dispersible second polymer; and

dichroic dye material incorporated in the polymeric film.

2. The optical device of claim 1, wherein the substrate is a polarizer.

3. The optical device of claim 2, wherein the substrate is a reflective polarizer.

4. The optical device of claim 3, wherein the reflective polarizer comprises a multilayer stack of at least two different sets of one or more polymeric layers, wherein the one or more polymeric layers of at least one of the sets are birefringent.

5. The optical device of claim 1, wherein the substrate is a mirror.

6. The optical device of claim 5, wherein the substrate is an IR mirror.

7. The optical device of claim 1, wherein the optical device further comprises an adhesive layer disposed on the polarizing film to adhere the polarizing film to the substrate.

8. The optical device of claim 7, wherein the substrate is a glass or plastic object.

9. A method of making an optical device, comprising:

forming a dispersion of polyvinyl alcohol and a water-soluble or water-dispersible second polymer in a solvent;

coating a substrate with the dispersion;

removing the solvent from the dispersion to form a polymeric film;

orienting the polymeric film; and

incorporating a dichroic dye material in the polymeric film.

10. The method of claim 9, wherein orienting the polymeric film comprises stretching the polymeric film in at least one direction.

11. The method of claim 9, wherein incorporating the dichroic dye material in the polymeric film comprises staining the polymeric film with the dichroic dye material.

12. The method of claim 9, wherein incorporating the dichroic dye material in the polymeric film comprises adding the dichroic dye material to the dispersion.

13. The method of claim 9, wherein the substrate is a reflective polarizer.

14. The method of claim 9, wherein the substrate is a mirror.

15. The method of claim 9, wherein the method further comprises removing the polymeric film from the substrate.

16. A display device, comprising:

a polymeric film comprising polyvinyl alcohol and a water-soluble or water-dispersible second polymer, the polymeric film being oriented; and

dichroic dye material incorporated in the polymeric film.

17. A method of making a polarizing film, the method comprising steps of:

forming a dispersion of polyvinyl alcohol and a water-soluble or water-dispersible second polymer in a solvent;

coating a substrate with the dispersion;

removing the solvent from the dispersion to form a polymeric film;

orienting the polymeric film; and

incorporating dichroic dye material in the polymeric film.

18. The method of claim 17, further comprising removing the polarizing film from the substrate.

19. The method of claim 17, wherein orienting the polymeric film comprises stretching the polymeric film in at least one direction.

20. The method of claim 17, wherein incorporating the dichroic dye material in the polymeric film comprises staining the polymeric film with the dichroic dye material.

21. The method of claim 17, wherein incorporating the dichroic dye material in the polymeric film comprises adding the dichroic dye material to the dispersion.