Liquid crystal display device having a pixel electrode with electrode branches and slits

Patent metadata

Field	Value
Publication number	US-11693281-B2
Application number	US-201916450332-A
Country	US
Kind code	B2
Filing date	Jun 24, 2019
Priority date	Dec 19, 2008
Publication date	Jul 4, 2023
Grant date	Jul 4, 2023

Abstract

A liquid crystal display device including first and second substrates; a liquid crystal layer arranged between the first and second substrates; a plurality of pixel regions each surrounded by a signal line and a scanning line; a counter electrode arranged on the first substrate; and a pixel electrode arranged on the first substrate, the pixel electrode including a plurality of electrode branches, a plurality of slits formed between the electrode branches, and a protrusion protruding in a first direction in which the scanning line extends, wherein at least one of the slits extends in a second direction in which the signal line extends.

First claim

The application is claimed as follows:

1. A liquid crystal display device comprising:
first and second substrates;
a liquid crystal layer arranged between the first and second substrates;
a plurality of pixel regions each surrounded by a scanning line and a signal line crossing the scanning line;
a counter electrode arranged on the first substrate;
a pixel electrode in one of the pixel regions arranged on the first substrate, the pixel electrode including
a plurality of electrode branches each having ends opposed to each other, the ends including a first branch end and a second branch end, the electrode branches being arranged in a longitudinal direction of the scanning line,
a plurality of slits formed between the electrode branches, the slits each having a closed shape,
a first connection portion connecting the first branch ends,

a second connection portion connecting the second branch ends and being opposed to the first connection portion in a longitudinal direction of the pixel electrode, and
a protrusion having a convex shape and protruding from one of the first connection portion and the second connection portion, in the longitudinal direction of the scanning line,

wherein at least one of the slits extends in a longitudinal direction of the signal line, crossing the longitudinal direction of the scanning line,
the protrusion overlaps the signal line and a part of the scanning line, the part surrounding the one of the pixel region, and does not overlap a part of the scanning line, the part surrounding another one of the pixel regions adjacent to the one of the pixel regions in the longitudinal direction of the scanning line,
the pixel electrode is connected to a thin film transistor,
the protrusion does not overlap the thin film transistor,
the electrode branches includes an outermost electrode branch that is outermost among the electrode branches and is located nearest to the protrusion in the longitudinal direction of the scanning line, among the electrode branches, and
the protrusion protrudes
from an area of the one of the first connection portion and the second connection portion, the area being connected to an end of the outermost electrode branch,
toward an outside of the one of the pixel regions in the longitudinal direction of the scanning line, such that an outermost end of the protrusion in the longitudinal direction of the scanning line is located outside an entirety of the electrode branches.

2. The liquid crystal display device according to claim 1 , further comprising:
a first slit disposed next to the signal line has a length greater than a width, and extends in a first slit extension direction in a lengthwise direction of the first slit based on an overall shape of the first slit; and
a plurality of second slits other than the first slit each have lengths greater than widths, and extend in a second slit extension direction in a lengthwise direction of the rest of the slits based on overall shapes of the second slits, the second slit extension direction being parallel to the signal line,
wherein the second slit extension direction is at an angle relative to the first slit extension direction.

3. The liquid crystal display device according to claim 2 , wherein a first cross angle (α 1 ) between the first slit extension direction and an alignment direction of the liquid crystal layer is larger than a second cross angle (α 2 ) between the second slit extension direction and the alignment direction of the liquid crystal layer.

4. The liquid crystal display device according to claim 3 , wherein the first cross angle (α 1 ) is equal to 7° or larger.

5. The liquid crystal display device according to claim 3 , wherein the first cross angle (α 1 ) is equal to or larger than 7° and equal to or smaller than 15°.

6. The liquid crystal display device according to claim 1 , wherein the slits of the pixel electrode have the same width.

7. The liquid crystal display device according to claim 1 , wherein the electrode branches of the pixel electrode have the same width.

8. The liquid crystal display device according to claim 1 , wherein the pixel electrode and the counter electrode are formed on the same layer surface.

9. The liquid crystal display device according to claim 1 , wherein:
two adjacent pixel regions of the plurality of the pixel regions above and below each scanning line are arranged in linear symmetry with the scanning line; and
the electrode branches and the slits of the pixel electrodes in the two adjacent pixel regions are alternately inclined with respect to the scanning line.

10. The liquid crystal display device according to claim 1 , wherein:
each pixel region is bent in linear symmetry at a center line of the pixel region; and
the electrode branches and the slits of the pixel electrode in each pixel region are alternately inclined with respect to the center line of the pixel region.

11. The liquid crystal display device according to claim 1 , wherein:
each pixel region is bent in linear symmetry at a center line of the pixel region;
the electrode branches and the slits of the pixel electrode in each pixel region are alternately inclined with respect to the center line of the pixel region; and
a connection branch connects bent portions of the electrode branches at the center line.

12. The liquid crystal display device according to claim 1 , wherein the protrusion of the pixel electrode in the one of the pixel regions overlaps an intersection of the signal line and the scanning line surrounding the one of the pixel regions.

13. The liquid crystal display device according to claim 1 , wherein:
the pixel electrode further includes a plurality of the protrusions including a first protrusion and a second protrusion both of which protrude in the longitudinal direction of the scanning line;
the first protrusion overlaps one of the scanning lines; and
the second protrusion overlaps a scanning line adjacent to the one of the scanning lines in the longitudinal direction of the signal line.

14. The liquid crystal display device according to claim 1 , wherein the protrusion is formed at a corner of the pixel electrode.

Assignees

• Japan Display Inc

Inventors

• Sakurai Yoshihiro
• Tanaka Hironao
• Yamaguchi Hidemasa

Classifications

• G02F1/134363 Primary

  for applying an electric field parallel to the substrate, i.e. in-plane switching [IPS] · CPC title

• G02F1/1337

  Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers · CPC title

• G02F1/134372

  for fringe field switching [FFS] where the common electrode is not patterned · CPC title

• G02F1/1343

  Electrodes {(reflective electrodes G02F1/133553)} · CPC title