Liquid crystal display device

Patent metadata

Field	Value
Publication number	US-10558085-B2
Application number	US-201716316141-A
Country	US
Kind code	B2
Filing date	Jul 5, 2017
Priority date	Jul 12, 2016
Publication date	Feb 11, 2020
Grant date	Feb 11, 2020

Abstract

The present invention provides a liquid crystal display device capable of achieving a high contrast ratio, a wide viewing angle, and a high-speed response. The liquid crystal display device includes an upper substrate; a lower substrate; and a liquid crystal layer sandwiched between the upper substrate and the lower substrate. The lower substrate includes a first electrode, and a second electrode and a third electrode arranged in a layer different from the first electrode. The first electrode includes a trunk portion and multiple branch portions branching from the trunk portion and is provided with an opening between the branch portions. The second electrode and the third electrode constitute a pair of comb-shaped electrodes and each include a trunk portion and multiple branch portions branching from the trunk portion. The branch portions of the first electrode are each bent at a predetermined angle. The electrodes each have a predetermined configuration.

First claim

The invention claimed is:

1. A liquid crystal display device comprising an upper substrate; a lower substrate; and a liquid crystal layer sandwiched between the upper substrate and the lower substrate,
wherein the lower substrate includes a first electrode, and a second electrode and a third electrode arranged in a layer different from the first electrode,
the first electrode includes a trunk portion and multiple branch portions branching from one side of the trunk portion and is provided with an opening between the branch portions,
the second electrode and the third electrode constitute a pair of comb-shaped electrodes and each include a trunk portion and multiple branch portions branching from one side of the trunk portion,
one of the branch portions of the second electrode has a part overlapping with the trunk portion of the first electrode and another part being in the opening of the first electrode when the lower substrate is viewed in a plan view so that an edge on the other side of the trunk portion of the first electrode extends in a lateral direction on an upper side of the first electrode,
the branch portions in the first electrode each include a bending point,
the liquid crystal display satisfies following Inequalities (1) to (4) where A is a vertical distance between an upper end and a lower end of the another part in the opening, B is a distance between the bending point and a center line between upper and lower ends of a branch portion of the third electrode, C is an angle formed between an extending direction of the branch portion of the second electrode and an extending direction of an edge on the one side of the trunk portion of the first electrode, and D is an angle formed between an extending direction of the trunk portion of the second electrode and an extending direction of an upper side portion from the bending point of a branch portion of the first electrode, and
the liquid crystal layer contains liquid crystal molecules aligned in a horizontal direction when no voltage is applied to each electrode,
1.5 μm≤ A   (1)

0 μm≤ B≤ 5.1 μm  (2)

0°≤ C≤ 20°  (3)

6.5°≤ D≤ 25°  (4).

2. The liquid crystal display device according to claim 1 ,
wherein the liquid crystal display device satisfies following Inequality (5):
D≤ 20°  (5).

3. The liquid crystal display device according to claim 1 , configured to execute a driving operation,
wherein the driving operation causes an electrode included in the lower substrate to generate an electric field for rotating liquid crystal molecules so that not less than two first regions and not less than two second regions are alternately arranged in a pixel, the first regions each rotating a first group of the liquid crystal molecules in a horizontal plane with respect to a main surface of the upper and lower substrates, the second regions each rotating a second group of the liquid crystal molecules in a direction opposite to the first group of the liquid crystal molecules in a horizontal plane with respect to the main surface.

4. The liquid crystal display device according to claim 3 , configured to switch between a first drive system and a second drive system,
wherein the first drive system executes the driving operation, and
the second drive system executes a driving operation of causing an electrode included in the lower substrate to generate an electric field for rotating liquid crystal molecules so that the number of first regions is not more than one and the number of second regions is not more than one in a pixel, the first regions each rotating a first group of the liquid crystal molecules in a horizontal plane with respect to a main surface of the upper and lower substrates, the second regions each rotating a second group of the liquid crystal molecules in a direction opposite to the first group of the liquid crystal molecules in a horizontal plane with respect to the main surface.

5. The liquid crystal display device according to claim 1 ,
wherein the first electrode is provided with a slit, or is a comb-shaped electrode.

6. The liquid crystal display device according to claim 1 , configured to execute a driving operation in which a potential difference between the first electrode and the third electrode is not less than a potential difference between the first electrode and the second electrode.

7. The liquid crystal display device according to claim 1 ,
wherein an average width of a branch portion of the third electrode is larger than an average width of a branch portion of the second electrode.

8. The liquid crystal display device according to claim 1 ,
wherein the first electrode is arranged on a side closer to the liquid crystal layer than the second electrode and the third electrode.

9. The liquid crystal display device according to claim 1 ,
wherein the liquid crystal molecules have positive anisotropy of dielectric constant.

10. The liquid crystal display device according to claim 1 ,
wherein the lower substrate includes a thin-film transistor element including an oxide semiconductor.

Assignees

• Sharp Kk

Inventors

• Tomotoshi Takuma
• Murata Mitsuhiro
• Iwata Yosuke
• Matsumura Satoshi

Classifications

• G02F1/133707 Primary

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

• G02F1/133711

  by organic films, e.g. polymeric films · CPC title

• G02F1/134363

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

• G02F1/1343

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

• G02F1/133784

  by rubbing · CPC title