Liquid crystal display and manufacturing method thereof

• US 8,518,498 B2
• Filed: 09/01/2010
• Issued: 08/27/2013
• Est. Priority Date: 09/02/2009
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: Song, Ki-Yong, Lee, Ki-Yeup, Kim, Jae-Hong, Kang, Yoon-Ho, Kim, Yong-Hwan
• Primary Examiner(s): Visconti, Geraldina
• Application Number:
  US12/874,068
• Publication Number:
  US 20110051057A1
• Time in Patent Office: 1,091 Days
• Field of Search: 428/1.1, 252/299.01, 349/86, 349/106, 349/182, 427/487, 427/508
• US Class Current: 428/1.1
• CPC Class Codes: C09K 2323/00 Functional layers of liquid crystal optical display excluding electroactive liquid crystal layer characterised by chemical composition
• CPC Class Codes: G02F 1/133512 Light shielding layers, e.g. black matrix G02F1/136209 takes precedence
• CPC Class Codes: G02F 1/133788 by light irradiation, e.g. linearly polarised light photo-polymerisation
• CPC Class Codes: G02F 1/13775 Polymer-stabilized liquid crystal layers
• CPC Class Codes: G02F 1/1393 the birefringence of the liquid crystal being electrically controlled, e.g. ECB-, DAP-, HAN-, PI-LC cells G02F1/1396, G02F1/141 take precedence
• CPC Class Codes: G02F 2201/086 UV absorbing

Abstract

The present invention relates to a liquid crystal display, wherein arrangement of liquid crystal molecules thereof is controlled by using a monomer that is polymerized by ultraviolet rays to provide a pre-tilt. To prevent damage to organic material layers when irradiating ultraviolet rays to the monomer, a blocking film made of an ultraviolet absorbing agent is formed on or over at least one such layer.

Claims

1. A liquid crystal display comprising:

a first panel;

a second panel including;

a thin film transistor;

an insulating layer comprising an organic material disposed on the thin film transistor;

a blocking film disposed directly on the insulating layer; and

a pixel electrode disposed on the blocking film; and

a liquid crystal layer between the first panel and the second panel, the liquid crystal layer having liquid crystal with a pre-tilt at least partially maintained by a polymerized polymer,

wherein the blocking film comprises an ultraviolet absorbing agent.

2. The liquid crystal display of claim 1, wherein

the ultraviolet absorbing agent is amorphous titanium oxide.

3. The liquid crystal display of claim 1, wherein the polymer includes:

a first polymerized polymer within the liquid crystal layer, and

a second polymer disposed along an inner surface of the first panel and an inner surface of the second panel, the inner surfaces each facing the liquid crystal layer.

4. The liquid crystal display of claim 1, wherein

the second panel further includes a color filter disposed under the insulating layer.

5. The liquid crystal display of claim 1,

wherein the pixel electrode includes a plurality of branch electrodes.

6. The liquid crystal display of claim 5, wherein

the pixel electrode has a plurality of sub-regions each having ones of the branch electrodes extending in a different direction from the ones of the branch electrodes in the other sub-regions.

7. The liquid crystal display of claim 6, wherein

intervals between the branch electrodes of one sub-region are different from intervals between branch electrodes of another sub-region.

8. The liquid crystal display of claim 1, wherein the second panel further comprises:

a first substrate;

a gate line disposed on the first substrate;

a step-down gate line parallel to the gate line;

a storage electrode line parallel to the gate line;

a gate insulating layer covering the gate line, the step-down gate line, and the storage electrode line;

a data line intersecting the gate line;

first and second sub-pixel electrodes disposed on the insulating layer and the blocking film; and

the thin film transistor comprising a first thin film transistor and a second thin film transistor,

wherein the first thin film transistor is connected to the gate line, the data line, and the first sub-pixel electrode; and

wherein the second thin film transistor is connected to the gate line, the data line, and the second sub-pixel electrode.

9. A method for manufacturing a liquid crystal display, comprising:

on a second panel, sequentially forming a thin film transistor, a color filter, an insulating layer comprising an organic material, a blocking film and a pixel electrode, wherein the blocking film is disposed directly on the insulating layer;

forming a liquid crystal layer between an first panel and the second panel;

applying an electric field to the liquid crystal layer; and

irradiating ultraviolet rays onto the liquid crystal.

10. The method of claim 9, wherein

the liquid crystal layer includes a polymerized monomer.

11. The method of claim 10, wherein

the monomer is a reactivity mesogen.

12. The method of claim 10, wherein

the monomer is about 0.1-0.5 wt % of the liquid crystal layer.

13. The method of claim 10, wherein

the polymerized monomer further comprises:

a first polymer disposed in the liquid crystal layer, and

a second polymer disposed along surfaces of the first panel and the second panel that face each other.

14. The method of claim 9, wherein

ultraviolet rays irradiated onto the liquid crystal layer have a wavelength of about 300 nm to about 320 nm.

15. The method of claim 9, further comprising

patterning the pixel electrode to form a plurality of branch electrodes.

16. The method of claim 9, wherein

the blocking layer comprises an ultraviolet absorbing agent.

17. The method of claim 16, wherein

the ultraviolet absorbing agent is amorphous titanium oxide.

18. A liquid crystal display comprising:

a first substrate;

a second substrate facing the first substrate;

a field generating electrode disposed on at least one of the first substrate and the second substrate; and

a liquid crystal layer interposed between the first substrate and the second substrate, the liquid crystal layer comprising liquid crystal molecules and a reactive mesogen,

wherein at least one of the first substrate and the second substrate includes an ultraviolet (UV)-blocking layer, the UV-blocking layer includes a UV-absorbing agent, and the UV-absorbing agent is an organic material including a chromophore comprising at least one selected from compounds represented by Formulae 1 and 2;

19. The liquid crystal display of claim 18, wherein

the reactive mesogen is polymerized to an alignment polymer through a UV light irradiating process.

20. The liquid crystal display of claim 19, wherein

the UV-blocking layer is disposed on the substrate that is not irradiated by the UV light among the first and second substrates.

21. The liquid crystal display of claim 20, wherein

the UV-blocking layer is disposed on or under the field generating electrode.

22. The liquid crystal display of claim 21, wherein

the UV-absorbing agent absorbs light having a wavelength of less than 400 nm.

23. The liquid crystal display of claim 21, wherein

a thickness of the UV-blocking layer is over 0.05 um.

24. A method for manufacturing a liquid crystal display, comprising:

forming a gate line including a gate electrode on a first substrate;

forming a gate insulating layer on the gate line;

forming a data line including a source electrode and a drain electrode facing the source electrode on the gate insulating layer;

forming a color filter;

forming a leveling layer on the color filter;

forming an ultraviolet (UV)-blocking layer on the leveling layer;

forming a common electrode on a second substrate; and

interposing a mixture comprising liquid crystal molecules and a reactive mesogen between the first substrate and the second substrate,

wherein the UV-blocking layer includes a UV-absorbing agent, and the UV-absorbing agent is an organic material including a chromophore.

25. The method of claim 24, further comprising

forming a pixel electrode on the UV-blocking layer of the first substrate.

26. The method of claim 24, further comprising

forming a pixel electrode under the UV-blocking layer of the first substrate.

27. The method of claim 24, further comprising:

applying a voltage to the pixel electrode and the common electrode; and

irradiating light to the mixture in the state in which the voltage is applied to the pixel electrode and the common electrode to light-polymerize the reactive mesogen.

28. The method of claim 27, further comprising:

turning off the voltage to the pixel electrode and the common electrode; and

irradiating light to the mixture in the state in which the voltage is not applied to the pixel electrode and the common electrode to light-polymerize the reactive mesogen.

29. The method of claim 24, wherein

the UV-absorbing agent absorbs light having a wavelength of less than 400 nm.

30. The method of claim 24, wherein

the chromophore comprises at least one selected from compounds represented by Formulae 1 and 2: