Liquid crystal display

Patent metadata

Field	Value
Publication number	US-9436045-B2
Application number	US-201414474538-A
Country	US
Kind code	B2
Filing date	Sep 2, 2014
Priority date	Mar 19, 2014
Publication date	Sep 6, 2016
Grant date	Sep 6, 2016

Abstract

A liquid crystal display includes a pixel that includes a first sub-pixel chargeable with a first voltage and a second sub-pixel chargeable with a second voltage different from the first voltage, a pixel electrode that includes a first sub-pixel electrode in the first sub-pixel and a second sub-pixel electrode in the second sub-pixel, a common electrode that faces the pixel electrode, and a liquid crystal layer between the pixel electrode and the common electrode. The first sub-pixel electrode includes a first trunk portion and a plurality of first branch portions protruding from and extending from one side of the first trunk portion. The second sub-pixel electrode includes a second trunk portion and a plurality of second and third branch portions that protrude from both sides of the second trunk portion and extend substantially parallel to the first branch portions.

First claim

What is claimed is:

1. A liquid crystal display including a pixel that includes a first sub-pixel chargeable with a first voltage and a second sub-pixel chargeable with a second voltage different from the first voltage, the liquid crystal display comprising: a pixel electrode that includes a first sub-pixel electrode in the first sub-pixel and a second sub-pixel electrode in the second sub-pixel; a common electrode that faces the pixel electrode; and a liquid crystal layer between the pixel electrode and the common electrode, wherein: the first sub-pixel electrode includes a first trunk portion and a plurality of first branch portions protruding from and extending from one side of the first trunk portion, the second sub-pixel electrode includes a second trunk portion and a plurality of second and third branch portions that protrude from both sides of the second trunk portion and extend substantially parallel to the first branch portions, and the second sub-pixel electrode substantially surrounds the first sub-pixel electrode.

2. The liquid crystal display as claimed in claim 1 , wherein the second branch portions have a length shorter than a length of the third branch portions.

3. The liquid crystal display as claimed in claim 1 , wherein end portions of the first branch portions face end portions of the second branch portions in a one-to-one correspondence.

4. The liquid crystal display as claimed in claim 3 , wherein each of the second branch portions has a length shorter than a length of a corresponding first branch portion of the first branch portions.

5. The liquid crystal display as claimed in claim 1 , wherein a width of the second trunk portion is equal to a length of each of the second branch portions.

6. The liquid crystal display as claimed in claim 5 , wherein the second trunk portion extends in a direction crossing the second and third branch portions.

7. The liquid crystal display as claimed in claim 1 , wherein the first voltage has a voltage level higher than a voltage level of the second voltage.

8. The liquid crystal display as claimed in claim 1 , wherein:
the pixel includes a plurality of domains having different alignment directions of liquid crystal molecules of the liquid crystal layer, and
the first, second, and third branch portions extend in different directions according to each domain.

9. The liquid crystal display as claimed in claim 8 , wherein:
the domains include first, second, third, and fourth domains, and
first, second, and third branch portions of each of the first, second, third, and fourth domains extend in first, second, third, or fourth directions different from each other.

10. The liquid crystal display as claimed in claim 9 , wherein the first trunk portion includes a cross portion having a cross shape and a plate portion having a quadrangular shape with four sides substantially perpendicular to the first, second, third, and fourth directions, respectively.

11. The liquid crystal display as claimed in claim 10 , wherein the common electrode includes a slit having a cross shape.

12. The liquid crystal display as claimed in claim 11 , wherein the slit overlaps with the cross portion of the first trunk portion when viewed in a plan view.

13. The liquid crystal display as claimed in claim 9 , wherein the second sub-pixel electrode surrounds at least a portion of the first sub-pixel electrode.

14. The liquid crystal display as claimed in claim 13 , wherein the first and second sub-pixel electrodes cover at least a portion of a quadrangular shape having chamfered corners.

15. The liquid crystal display as claimed in claim 9 , wherein:
the first, second, third, and fourth domains form one domain unit, and
the domain unit is provided in a plural number in one pixel.

16. The liquid crystal display as claimed in claim 1 , further comprising:
a plurality of gate lines; and
a plurality of data lines,
wherein the pixel is connected to a corresponding gate line of the gate lines and a corresponding data line of the data lines.

17. The liquid crystal display as claimed in claim 16 , wherein the pixel includes:
a first thin film transistor that applies the first voltage to the first sub-pixel electrode; and
a second thin film transistor that applies the second voltage to the second sub-pixel electrode, the first thin film transistor being connected to one gate line of the gate lines and one data line of the data lines, and the second thin film transistor being connected to the one gate line of the gate lines and another data line of the data lines, the another data line being not connected to the first thin film transistor.

18. The liquid crystal display as claimed in claim 1 , wherein:
the first sub-pixel includes a first thin film transistor to apply a first data voltage to the first sub-pixel electrode and a first liquid crystal capacitor connected to the first thin film transistor,
the second sub-pixel includes a second thin film transistor to apply a second data voltage to the second sub-pixel, a second liquid crystal capacitor connected to the second thin film transistor, and a third thin film transistor substantially and simultaneously turned on with the second thin film transistor to apply a storage voltage to the second sub-pixel electrode, and
the second sub-pixel electrode is applied with a voltage divided by a resistance of the turn-on resistor of the second and third thin film transistors.

19. The liquid crystal display as claimed in claim 1 , wherein:
the first sub-pixel includes a first thin film transistor to apply a first pixel voltage to the first sub-pixel electrode and a first liquid crystal capacitor connected to the first thin film transistor, and
the second sub-pixel includes a second thin film transistor to apply a second pixel voltage to the second sub-pixel, a second liquid crystal capacitor connected to the second thin film transistor, a third thin film transistor turned on at a different time point from the second thin film transistor, and a coupling capacitor electrically connected to the second liquid crystal capacitor when the third thin film transistor is turned on to lower a voltage charged in the second liquid crystal capacitor.

Assignees

• Samsung Display Co Ltd

Inventors

• Song Heerim
• Lim Sang-Uk
• Jeon Sangjin

Classifications

• G02F2001/134345

  Physics · mapped topic

• G02F1/1368

  in which the switching element is a three-electrode device {(G02F1/136277 takes precedence)} · CPC title

• G02F1/13624

  having more than one switching element per pixel · CPC title

• G02F1/133707

  Structures for producing distorted electric fields, e.g. bumps, protrusions, recesses, slits in pixel electrodes · CPC title

• G02F1/134309 Primary

  characterised by their geometrical arrangement · CPC title