Liquid crystal display device and method of driving the same

Patent metadata

Field	Value
Publication number	US-9664957-B2
Application number	US-201314411455-A
Country	US
Kind code	B2
Filing date	Jun 25, 2013
Priority date	Jun 25, 2012
Publication date	May 30, 2017
Grant date	May 30, 2017

Abstract

Provided are a liquid crystal display device and a method for driving same. The liquid crystal display device comprises the liquid crystal display device in a PVA mode, an LVA mode, an FFS mode, and in an IPS mode. The liquid crystal display device comprises a liquid crystal layer, which comprises a negative nematic liquid crystal, a positive nematic liquid crystal, and a ferroelectric liquid crystal. The liquid crystal display device comprises a non-ferroelectric liquid crystal and the ferroelectric liquid crystal.

First claim

The invention claimed is:

1. A liquid crystal display device, comprising:
a first substrate;
a second substrate separated from and opposing the first substrate;
a liquid crystal layer between the first and second substrates;
a first electrode between the first substrate and the liquid crystal layer and comprising a first slit; and
a second electrode between the liquid crystal layer and the second substrate and comprising a second slit,
wherein the liquid crystal layer comprises a negative nematic liquid crystal, a positive nematic liquid crystal and a ferroelectric liquid crystal,
wherein the liquid crystal layer includes a mixture of the positive nematic liquid crystal, the negative nematic liquid crystal, and the ferroelectric liquid crystal, the mixture being disposed throughout the entire liquid crystal layer.

2. The liquid crystal display device of claim 1 , wherein the first electrode and the second electrode are disposed so that the first slit and the second slit are not overlapped when seen from a plan view.

3. The liquid crystal display device of claim 1 , wherein the liquid crystal display device is in a patterned vertical alignment (PVA) mode.

4. The liquid crystal display device of claim 1 , further comprising a first alignment layer between the first electrode and the liquid crystal layer; and a second alignment layer between the second electrode and the liquid crystal layer.

5. The liquid crystal display device of claim 4 , wherein at least one of the first alignment layer and the second alignment layer comprises a reactive mesogen material.

6. The liquid crystal display device of claim 1 , wherein the liquid crystal layer comprises from about 70 wt % to about 99.9 wt % of the negative nematic liquid crystal; and from about 0.1 wt % to about 30 wt % of the positive nematic liquid crystal and the ferroelectric liquid crystal.

7. The liquid crystal display device of claim 6 , wherein from about 10 wt % to about 99 wt % of the ferroelectric liquid crystal is comprised in the positive nematic liquid crystal and the ferroelectric liquid crystal.

8. The liquid crystal display device of claim 6 , wherein the liquid crystal layer further comprises a reactive mesogen material.

9. The liquid crystal display device of claim 8 , wherein the liquid crystal layer comprises from about 0.1 wt % to about 30 wt % of the positive nematic liquid crystal and the ferroelectric liquid crystal; from about 0.01 wt % to about 3wt % of the reactive mesogen material; and a remainder of the negative nematic liquid crystal.

10. A liquid crystal display device, comprising:
a first electrode and a second electrode separated from and opposing to each other; and
a liquid crystal layer filling up a space between the first and second electrodes and comprising a plurality of liquid crystal molecules having a first alignment direction perpendicular to the surface of the first or second electrode when no potential difference is present between the first and second electrodes,
wherein the liquid crystal layer comprises a negative nematic liquid crystal, a positive nematic liquid crystal and a ferroelectric liquid crystal,
the plurality of liquid crystal molecules performs changing operation to have a second alignment direction substantially in parallel to an extended direction of the first or second electrode when potential difference is generated between the first and second electrodes,
the changing operation of the liquid crystal molecules comprises a first alignment step and a second alignment step in order,
the liquid crystal molecules change to have a third alignment direction different from the first or second alignment direction in the first alignment step, and
the liquid crystal molecules of the third alignment direction change to have the second alignment direction in the second alignment step,
wherein the liquid crystal layer includes a mixture of the positive nematic liquid crystal, the negative nematic liquid crystal, and the ferroelectric liquid crystal, the mixture being disposed throughout the entire liquid crystal layer.

11. The liquid crystal display device of claim 10 , further comprising an alignment layer disposed at least a portion between the liquid crystal layer and the first electrode and between the liquid crystal layer and the second electrode,
wherein at least one of the liquid crystal layer and the alignment layer comprises a reactive mesogen material, and
the plurality of liquid crystal molecules of the first alignment direction change to have the second alignment direction when potential difference is generated between the first and second electrodes due to the reactive mesogen.

12. The liquid crystal display device of claim 11 , wherein the alignment layer comprises at least one of a first alignment layer between the first electrode and the liquid crystal layer; and a second alignment layer between the second electrode and the liquid crystal layer.

13. The liquid crystal display device of claim 11 , wherein the alignment layer comprises a base material and a reactive mesogen material,
wherein the base material comprises at least one selected from the group consisting of polyamic acid, polyimide, lecithin, nylon and polyvinyl alcohol (PVA).

14. The liquid crystal display device of claim 10 , wherein the liquid crystal layer comprises from about 70 wt % to about 99.9 wt % of the negative nematic liquid crystal; and from about 0.1 wt % to about 30 wt % of the positive nematic liquid crystal and the ferroelectric liquid crystal.

15. The liquid crystal display device of claim 14 , wherein from about 10 wt % to about 99 wt % of the ferroelectric liquid crystal is comprised in the positive nematic liquid crystal and the ferroelectric liquid crystal.

16. The liquid crystal display device of claim 15 , wherein the liquid crystal layer comprises a reactive mesogen material, and
the liquid crystal layer comprises from about 0.1 wt % to about 30 wt % of the positive nematic liquid crystal and the ferroelectric liquid crystal; from about 0.01 wt % to about 3 wt % of the reactive mesogen material; and a remainder of the negative nematic liquid crystal.

17. The liquid crystal display device of claim 10 , wherein at least one of the first electrode and the second electrode has a slit.

18. The liquid crystal display device of claim 17 , wherein the first electrode comprises a first slit having a square ring shape and extended along an edge portion of the first electrode, and
the second electrode comprises a second slit having a cross shape and penetrating a center of the second electrode.

19. The liquid crystal display device of claim 18 , wherein when potential different is generated between the first and second electrodes,
liquid crystal molecules positioned at the first and second slits have a second alignment direction that is a perpendicular direction to the first and second slits, and
liquid crystal molecules separated apart from the first and second slits have a second alignment direction that has an angle of about 45° or about 135° with respect to the first and second slits.

20. The liquid crystal display device of claim 18 , wherein the first slit of the first electrode has a cut portion at the middle thereof.

21. The liquid crystal display device of claim 17 , wherein the first electrode comprises:
a stem part penetrating the center of the first electrode and having a cross shape; and
branch parts extended in a radial direction from the stem part and separated apart from e

Assignees

• Industry-Univ Coop Found Hanyang Univ

Inventors

• Kim Jae-Hoon
• Lee You-Jin

Classifications

• G02F2001/133742

  Physics · mapped topic

• G02F2001/13712

  Physics · mapped topic

• G02F1/141 Primary

  using ferroelectric liquid crystals · CPC title

• G02F1/134309 Primary

  characterised by their geometrical arrangement · CPC title

• G02F2001/134318

  Physics · mapped topic