Liquid crystal display device

Patent metadata

Field	Value
Publication number	US-9494832-B2
Application number	US-201314414391-A
Country	US
Kind code	B2
Filing date	Jul 16, 2013
Priority date	Jul 23, 2012
Publication date	Nov 15, 2016
Grant date	Nov 15, 2016

Abstract

Provided is a liquid crystal display device having excellent viewing angle characteristics and high contrast in a display mode using both a vertical electric field and a horizontal electric field. This liquid crystal display device is provided with a first substrate and a second substrate disposed facing each other, and a liquid crystal layer held between said first and second substrates. The liquid crystal layer contains liquid crystal molecules having a negative dielectric anisotropy. The first substrate is provided with a flat plate first electrode, a first insulating layer, and a second electrode provided in a layer other than that of the first electrode and provided separated from the first electrode by the first insulating layer. The second electrode has multiple comb-tooth sections and multiple slits, and the second substrate has a flat plate third electrode. Defining V 1 as the potential difference between the first electrode and the third electrode, V 2 as the potential difference between the first electrode and the second electrode, and V 2 _ B as the potential difference between the first electrode and the second electrode when the lowest gradation is showed, V 1 , V 2 and V 2 _ B satisfy 0<|V 2 _ B |≦|V 2 |<|V 1 |.

First claim

What is claimed is:

1. A liquid crystal display device, comprising:
a first substrate and a second substrate opposing each other; and
a liquid crystal layer sandwiched between the first and second substrates,
wherein the liquid crystal layer contains liquid crystal molecules having negative dielectric anisotropy,
wherein the first substrate includes a uniformly planar first electrode, a first insulating layer, and a second electrode provided in a different layer from the first electrode across the first insulating layer,
wherein the second electrode has a plurality of teeth and a plurality of slits separating the teeth,
wherein each of the first and second substrates has a polarizing plate thereon, and polarizing axes of the respective polarizing plates are arranged in a crossed Nicols state with each other, and are perpendicular or parallel to a lengthwise direction of said slits,
wherein the second substrate includes a uniformly planar third electrode, and
wherein the liquid crystal display device is configured such that V 1 , V 2 , and V 2 _ B satisfy the following formula (1) for each of gradation levels being displayed, including white and black displays, where a potential between the first electrode and the third electrode is V 1 , a potential between the first electrode and the second electrode is V 2 , and a potential between the first electrode and the second electrode at a lowest gradation is V 2 _ B :
0<| V 2 _ B |≦|V 2 |<|V 1 |  (1).

2. The liquid crystal display device according to claim 1 , wherein the value V 2 _ B satisfies the following formula (2):

0
<



V

2
⁢
_B



≤

ɛ
⊥

⁢

d
1

ɛ
1

⁢

d
LC

+

ɛ
⊥

⁢

d
1

⁢



V
1



+
0.5

,

(
2
)

where d LC represents a thickness of the liquid crystal layer, ∈ ⊥ represents a permittivity in a direction perpendicular to a liquid crystal director, d 1 represents a thickness of the first insulating layer, and ∈ 1 represents a permittivity of the first insulating layer.

3. The liquid crystal display device according to claim 1 ,
wherein the second substrate has an alignment film,
wherein a second insulating layer is present between the third electrode and the alignment film, and
wherein the value V 2 _ B satisfies the following formula (3):

0
<



V

2
⁢
_B



≤

ɛ
2

⁢

ɛ
⊥

⁢

d
1

ɛ
1

⁢

ɛ
⊥

⁢

d
2

+

ɛ
1

⁢

ɛ
2

⁢

d
LC

+

ɛ
2

⁢

ɛ
⊥

⁢

d
1

⁢



V

Assignees

• Sharp Kk

Inventors

• Iwata Yosuke
• Murata Mitsuhiro
• Tanaka Kohhei
• Jinda Akihito
• Yoshida Hidefumi

Classifications

• G02F1/134309 Primary

  characterised by their geometrical arrangement · CPC title

• G02F1/1337

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

• G02F1/133345

  Insulating layers (G02F1/1335, G02F1/1337, G02F1/135, G02F1/136 take precedence) · CPC title

• G09G2300/0447

  for multi-domain technique to improve the viewing angle in a liquid crystal display, such as multi-vertical alignment [MVA] · CPC title

• G09G3/36

  using liquid crystals · CPC title