LIQUID CRYSTAL DISPLAY DEVICE, ALIGNMENT FILM, AND METHODS FOR MANUFACTURING THE SAME

• US 20130101755A1
• Filed: 07/24/2012
• Published: 04/25/2013
• Est. Priority Date: 10/20/2011
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Jang-Hyun Kim, Jun-Hyup Lee, Sang-Gyun Kim, Tae-Hoon Kim
• Inventors: Oh, Keun-Chan, Lee, Jun-Hyup, Kim, Sang-Gyun, Kim, Jang-Hyun, LEE, Taek-Joon, Kim, Tae-Hoon
• Granted Patent: US 8,962,106 B2
• Time in Patent Office: Days
• US Class Current: 428/1.23
• CPC Class Codes: C09K 2323/02 Alignment layer characterised by chemical composition
• CPC Class Codes: C09K 2323/021 Inorganic, e.g. glass or silicon oxide
• CPC Class Codes: C09K 2323/023 Organic silicon compound, e.g. organosilicon
• CPC Class Codes: G02F 1/133707 Structures for producing distorted electric fields, e.g. bumps, protrusions, recesses, slits in pixel electrodes
• CPC Class Codes: G02F 1/133711 by organic films, e.g. polymeric films
• CPC Class Codes: G02F 1/133746 for high pretilt angles, i.e. higher than 15 degrees
• CPC Class Codes: G02F 1/133753 with different alignment orientations or pretilt angles on a same surface, e.g. for grey scale or improved viewing angle
• CPC Class Codes: G02F 1/133788 by light irradiation, e.g. linearly polarised light photo-polymerisation
• CPC Class Codes: H05K 13/00 Apparatus or processes specially adapted for manufacturing or adjusting assemblages of electric components

Abstract

An alignment film includes a first pre-tilt functional group, a second pre-tilt functional group and a first vertical alignment functional group, which are linked to polysiloxane on a substrate. The first vertical alignment functional group includes a cyclic compound and is aligned substantially perpendicularly to the substrate. The first pre-tilt functional group is cross-linked to the second pre-tilt functional group and tilted with respect to the substrate.

Claims

1. An alignment film comprising:

a first pre-tilt functional group, a second pre-tilt functional group and a first vertical alignment functional group, which are linked to polysiloxane on a substrate;

wherein the first vertical alignment functional group includes a cyclic compound and is aligned substantially perpendicularly to the substrate;

wherein the first pre-tilt functional group is cross-linked to the second pre-tilt functional group and tilted with respect to the substrate.

2. The alignment film of claim 1, wherein a mol % composition ratio of the first vertical alignment functional group and the first pre-tilt functional group is about 1:

about 1.5 to about 11.

3. The alignment film of claim 2, wherein the first pre-tilt functional group is greater than the second pre-tilt functional group in chain length.

4. The alignment film of claim 3, further comprising one of a sol-gel catalyst or an aggregation inhibitor linked to the polysiloxane.

5. The alignment film of claim 4, further comprising a second vertical alignment functional group linked to the polysiloxane, wherein the second vertical alignment functional group does not include a cyclic compound.

6. The alignment film of claim 3, further comprising a second vertical alignment functional group linked to the polysiloxane, wherein the second vertical alignment functional group does not include a cyclic compound.

7. The alignment film of claim 2, further comprising one of a sol-gel catalyst or an aggregation inhibitor linked to the polysiloxane.

8. The alignment film of claim 7, further comprising a second vertical alignment functional group linked to the polysiloxane, wherein the second vertical alignment functional group does not include a cyclic compound.

9. The alignment film of claim 2, further comprising a second vertical alignment functional group linked to the polysiloxane, wherein the second vertical alignment functional group does not include a cyclic compound.

10. The alignment film of claim 2, wherein the first vertical alignment functional group includes any one of an alkyl benzene group, a cholesteric group, an alkylated alicyclic group, or an alkylated aromatic group.

11. The alignment film of claim 1, wherein the first pre-tilt functional group is greater than the second pre-tilt functional group in chain length.

12. The alignment film of claim 11, further comprising one of a sol-gel catalyst or an aggregation inhibitor linked to the polysiloxane.

13. The alignment film of claim 12, further comprising a second vertical alignment functional group linked to the polysiloxane, wherein the second vertical alignment functional group does not include a cyclic compound.

14. The alignment film of claim 11, further comprising a second vertical alignment functional group linked to the polysiloxane, wherein the second vertical alignment functional group does not include a cyclic compound.

15. The alignment film of claim 11, wherein the first and second pre-tilt functional groups each include a different one of a vinyl group, a styrene group, a methacrylate group, a cinnamate group, or an acrylic group.

16. The alignment film of claim 11, wherein a mol % composition ratio of the first vertical alignment functional group, the first pre-tilt functional group, and the second pre-tilt functional group is about 1:

about 1.5 to about 11;

about 1 to about 3.

17. The alignment film of claim 1, further comprising one of a sol-gel catalyst or an aggregation inhibitor linked to the polysiloxane.

18. The alignment film of claim 17, further comprising a second vertical alignment functional group linked to the polysiloxane, wherein the second vertical alignment functional group does not include a cyclic compound.

19. The alignment film of claim 17, wherein the sol-gel catalyst or the aggregation inhibitor includes any one of an amino group or a thiol group.

20. The alignment film of claim 17, wherein a mol % composition ratio of the first vertical alignment functional group, the first pre-tilt functional group, and the aggregation inhibitor is about 1:

about 1.5 to about 11;

about 0.5 to about 4.

21. The alignment film of claim 1, further comprising a second vertical alignment functional group linked to the polysiloxane, wherein the second vertical alignment functional group does not include a cyclic compound.

22. The alignment film of claim 21, wherein a mol % composition ratio of the first vertical alignment functional group, the second vertical alignment functional group, and the first pre-tilt functional group is about 1:

about 0.3 to about 3;

about 1.5 to about 11.

23. A liquid crystal display device comprising:

a liquid crystal layer including liquid crystal molecules and interposed between a first display panel and a second display panel; and

an alignment film formed on at least one of the first and second display panels, wherein the alignment film includes a first pre-tilt functional group, a second pre-tilt functional group and a first vertical alignment functional group, which are linked to polysiloxane;

wherein the first vertical alignment functional group includes a cyclic compound and is configured to align first liquid crystal molecules among the liquid crystal molecules to be substantially perpendicular to the first or second display panels;

wherein the first pre-tilt functional group is cross-linked to the second pre-tilt functional group and is configured to align second liquid crystal molecules among the liquid crystal molecules to be tilted with respect to the first or second display panels.

24. A method for forming an alignment film on a display panel comprising:

providing a display panel having an electrode formed thereon;

forming a surface alignment reactant on the electrode, wherein the surface alignment reactant comprises a first surface alignment material including a plurality of pre-tilting functional groups having different chain lengths bonded to a siloxane and a second surface alignment material including a phase separation enhancer functional group bonded to a siloxane, wherein the first surface alignment material is a vertical alignment material configured to align liquid crystals substantially perpendicular to a plane of the display panel;

performing a first heating process on the surface alignment reactant to cause the surface alignment reactant to become phase separated into a surface inorganic layer and a surface functional group layer, wherein the surface inorganic layer includes the second surface alignment material and the surface functional group layer includes the first surface alignment material; and

irradiating the surface functional group layer to thereby form an alignment layer on the electrode.

25. The method of claim 24, wherein the electrode is one of a pixel electrode or a common electrode.

26. The method of claim 24, wherein the phase separation enhancer functional group is a methyl group.

27. The method of claim 24, wherein the siloxanes included in the surface inorganic layer and the surface functional group layer are transformed into polysiloxanes by the first heating process.

28. The method of claim 24, wherein prior to irradiating the surface functional group layer, the method further comprises performing a second heating process on the surface inorganic layer and the surface functional group layer such that the surface functional group layer is cured, the polysiloxanes in the surface inorganic layer and the surface functional group layer undergo cross-linking reactions and wherein the surface inorganic layer is transformed into a surface inorganic alignment film by the cross-linking reactions.

29. The method of claim 28, wherein the irradiating the surface functional group layer transforms the surface functional group layer into a hardening layer such that the alignment layer is formed including the hardening layer and the surface inorganic alignment film.

30. The method of claim 26, wherein the pre-tilting functional groups are selected from the group consisting of a vinyl group, a styrene group, a methacrylate group, cinnamate group, or an acrylic group.

31. The method of claim 24, wherein the first heating process is performed for about 100 seconds to about 140 seconds and at a temperature of about 80°

C. to about 110°

C.

32. The method of claim 28, wherein the second heating process is performed for about 1000 seconds to about 1400 seconds and at a temperature of about 200°

C. to about 240°

C.

33. The method of claim 24, wherein the surface alignment reactant further includes a solvent selected from the group consisting of chlorobenzene, dimethyl sulfoxide, dimethylformamide, N-methylpyrrolidone, γ

-butyrolactone, methyl methoxy butanol, ethoxy methyl butanol, toluene, chloroform, methyl cellosolve, butyl cellosolve, butyl carbitol, tetrahydrofuran, and a combination thereof.

34. The method of claim 33, wherein the solvent is vaporized by the first heating process.