Dichroic polarizing film and optical polarizer containing the film

• US 6,610,356 B2
• Filed: 10/09/2001
• Issued: 08/26/2003
• 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., Williams, Brian H., Merrill, William W.
• Primary Examiner(s): Yoon, Tae H.
• Application Number:
  US09/974,225
• Publication Number:
  US 20020017736A1
• Time in Patent Office: 686 Days
• Field of Search: 427/163.1, 428/1.31, 428/910, 252/585, 359/584, 528/502
• 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. A method of making a polarizing film, the method comprising:

forming a polymeric film on a substrate, the polymeric film comprising polyvinyl alcohol and a water-soluble or water-dispersible second polymer in a ratio of polyvinyl alcohol;

second polymer in the range of 5;

1 to 100;

1 by weight;

orienting the polymeric film while disposed on the substrate;

incorporating dichroic dye material into the polymeric film; and

removing the polymeric film from the substrate.

2. The method of claim 1, wherein incorporating dichroic dye material into the polymeric film occurs prior to removing the polymeric film from the substrate.

3. The method of claim 1, wherein incorporating dichroic dye material into the polymeric film occurs after orienting the polymeric film.

4. The method of claim 1, wherein incorporating dichroic dye material into the polymeric film occurs before orienting the polymeric film.

5. The method of claim 1, further comprising disposing the polymeric film on a second substrate after removing the polymeric film from the substrate.

6. The method of claim 5, wherein disposing the polymeric film on a second substrate comprises adhering the polymeric film to the second substrate.

7. The method of claim 5, wherein the substrate comprises a reflective polarizer.

8. The method of claim 5, wherein the substrate comprises a mirror.

9. The method of claim 1, wherein orienting the polymeric film comprises stretching the polymeric film in at least one direction.

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

21. The method of claim 1, wherein the second polymer is selected from the group consisting of polyvinyl pyrrolidone and polyesters.

11. A method of making a display device, the method comprising:

forming a polymeric film on a substrate, the polymeric film comprising polyvinyl alcohol and a water-soluble or water-dispersible second polymer in a ratio of polyvinyl alcohol;

second polymer in the range of 5;

1 to 100;

1 by weight;

orienting the polymeric film while on the substrate;

incorporating dichroic dye material into the polymeric film to form a polarizing film;

removing the polymeric film from the substrate; and

positioning the polarizing film in the display device.

12. The method of claim 11, further comprising disposing the polymeric film on a second substrate after removing the polymeric film from the substrate.

13. The method of claim 12, wherein disposing the polymeric film on a second substrate comprises adhering the polymeric film to the second substrate.

14. The method of claim 12, wherein the substrate comprises a reflective polarizer.

15. The method of claim 12, wherein the substrate comprises a mirror.

22. The method of claim 11, wherein the second polymer is selected from the group consisting of polyvinyl pyrrolidone and polyesters.

16. A method of making an optical device, the method comprising:

forming a polymeric film on a substrate, the polymeric film comprising polyvinyl alcohol and a water-soluble or water-dispersible second polymer in a ratio of polyvinyl alcohol;

second polymer in the range of 5;

1 to 100;

1 by weight;

orienting the polymeric film while on the substrate;

incorporating dichroic dye material into the polymeric film to form a polarizing film;

removing the polymeric film from the substrate; and

positioning the polarizing film in the optical device.

17. The method of claim 16, further comprising disposing the polymeric film on a second substrate after removing the polymeric film from the substrate.

18. The method of claim 17, wherein disposing the polymeric film on a second substrate comprises adhering the polymeric film to the second substrate.

19. The method of claim 17, wherein the substrate comprises a reflective polarizer.

20. The method of claim 17, wherein the substrate comprises a mirror.

23. The method of claim 16, wherein the second polymer is selected from the group consisting of polyvinyl pyrrolidone and polyesters.