ALIGNMENT LAYER WITH REACTIVE MESOGENS FOR ALIGNING LIQUID CRYSTAL MOLECULES

• US 20130012654A1
• Filed: 09/13/2012
• Published: 01/10/2013
• Est. Priority Date: 08/08/2003
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.), Merck Patent GmbH (Merck & Co., Inc.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.), Merck Patent GmbH (Merck & Co., Inc.)
• Inventors: HARDING, Richard, MAY, Alison Linda, GREENFIELD, Simon, LUB, Johan, DOORNKAMP, Ciska, WEGH, Ren Theodorus
• Granted Patent: US 8,481,130 B2
• Time in Patent Office: Days
• US Class Current: 524/606
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C09K 2323/02 Alignment layer characterised by chemical composition
• CPC Class Codes: C09K 2323/027 Polyimide
• CPC Class Codes: G02F 1/133711 by organic films, e.g. polymeric films
• CPC Class Codes: G02F 1/133723 Polyimide, polyamide-imide
• CPC Class Codes: G02F 1/133726 made of a mesogenic material
• CPC Class Codes: Y10T 428/31721 Of polyimide

Abstract

The invention relates to an alignment layer with improved adhesion to liquid crystal (LC) films, to a precursor material used for the preparation of such a layer, to a laminate comprising such a layer and at least one LC polymer film, and to the use of the alignment layer and the laminate for optical, electrooptical, decorative or security uses and devices, wherein the alignment layer and the precursor material comprise at least one reactive mesogen in monomeric, oligomeric or polymeric form.

Claims

1-21. -21. (canceled)

22. A method for preparing an alignment layer for aligning liquid crystal molecules, said alignment layer comprising:

(a) a polymer film formed from a polymer or from a polymer precursor and (b) at least one reactive mesogen additive in monomeric, oligomeric or polymeric form within said polymer film, wherein said at least one reactive mesogen additive is not said polymer or said polymer precursor used to form said polymer film, and wherein, after preparation of said alignment layer, said alignment layer contains unreacted polymerizable groups in said at least one reactive mesogen additive, said method comprising;

depositing a layer of a solution onto a surface, said solution containing said polymer or polymer precursor, and processing said layer of solution to form said alignment layer, wherein said at least one reactive mesogen additive is incorporated into said layer of solution before said processing, and wherein the concentration of said at least one reactive mesogen additive in said polymer or polymer precursor is 0.5 to 4% by weight.

23. A method according to claim 22, wherein said at least one reactive mesogen additive is present in monomeric or oligomeric form in the alignment layer after the preparation of said alignment layer.

24. A method according to claim 23, wherein said at least one reactive mesogen additive is present in monomeric form in the alignment layer after the preparation of said alignment layer.

25. A method according to claim 22, wherein said alignment layer is obtained from a polymer precursor comprising at least one reactive mesogen.

26. A method according to claim 22, wherein said alignment layer comprises a polyimide film and said at least one reactive mesogen additive within said polyimide film, and said alignment layer is obtained from a solution comprising a polyimide precursor and said at least one reactive mesogen additive.

27. A method according to claim 26, wherein said polyimide film has repeating units of formula A

28. A method according to claim 22, wherein said at least one reactive mesogen additive is of one of the following formulae:

29. A method according to claim 28, wherein the concentration of said at least one reactive mesogen in said polymer or polymer precursor is 1 to 2% by weight.

30. A method according to claim 22, wherein said alignment layer has a birefringence of less than 0.05.

31. A method according to claim 22, wherein said alignment layer has a birefringence of less than 0.005.

32. A method according to claim 22, wherein said at least one reactive mesogen is added to a solution of said polymer or said polymer precursor.

33. A method according to claim 22, wherein the concentration of said at least one reactive mesogen in said polymer or polymer precursor is comprises 1 to 2% by weight.

34. A method according to claim 22, wherein, after said alignment layer is processed from said layer of solution, said at least one reactive mesogen is physically trapped within said polymer of said polymer film.

35. A method according to claim 34, wherein said alignment layer is obtained by applying to a substrate a solution of said polymer of said polymer film, and said solution further contains said at least one reactive mesogen, said solution being applied to said substrate, and processing of said alignment layer comprises heating said solution to remove excess solvent.

36. A method according to claim 22, wherein said alignment layer is obtained by applying to a substrate a solution comprising said at least one reactive mesogen and a polymer precursor for forming said polymer film, and processing of said alignment layer comprises subjecting said polymer precursor to polymerization.

38. In an optical, electrooptical, information storage, decorative and security device, the improvement wherein said device contains an alignment layer prepared according to claim 22.

39. An optical component or device comprising at least one alignment layer prepared according to claim 22.

40. A liquid crystal display comprising at least one alignment layer prepared according to claim 22.

41. A solution for preparing an alignment layer, said alignment layer comprising:

(a) a polymer film formed from a polymer or a polymer precursor and (b) at least one reactive mesogen additive in monomeric, oligomeric or polymeric form within said polymer film, wherein said at least one reactive mesogen additive is not said polymer or said polymer precursor used to form said polymer film, said solution comprising;

a solvent, said at least one reactive mesogen additive, and a polymer or a polymer precursor, said polymer or polymer precursor comprising;

a polyimide polymer or a precursor of said polyimide polymer,

wherein in said solution the concentration of said at least one reactive mesogen relative to said polymer or polymer precursor before forming said film is 0.5 to 4% by weight.

42. A polymer precursor according to claim 41, wherein said at least one reactive mesogen additive is of one of the following formulae:

43. A polymer precursor according to claim 41, wherein said polymer or polymer precursor can form an alignment layer having a birefringence of less than 0.05.

44. A polymer precursor according to claim 41, wherein said polymer or polymer precursor can form an alignment layer having birefringence of less than 0.005.

45. A polymer precursor according to claim 41, wherein said polymer or polymer precursor comprises 1 to 2% by weight of said at least one reactive mesogen.

46. A method for preparing an alignment layer for aligning liquid crystal molecules, said alignment layer comprising:

(a) a polymer film formed from a polymer or from a polymer precursor and (b) at least one reactive mesogen additive in monomeric, oligomeric or polymeric form within said polymer film, wherein said at least one reactive mesogen additive is not said polymer or polymer precursor used to form said polymer film, and wherein, after preparation of said alignment layer, said alignment layer contains unreacted polymerizable groups in said at least one reactive mesogen additive, said method comprising;

depositing a layer of a solution onto a surface, said solution containing said polymer or polymer precursor, and processing said layer of solution to form said alignment layer, wherein said at least one reactive mesogen additive is incorporated into said layer of solution before said processing, and said at least one reactive mesogen additive is miscible with said polymer film formed from a polymer or from a polymer precursor.