# US 9,436,024 B2 · Lateral electric field type liquid crystal display device

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 9,436,024 B2
- Document ID: US9436024B2
- Status: Granted
- Kind: B2
- Application number: 13/781,797
- Filed: 2013-03-01
- Published: 2013-09-05
- Granted: 2016-09-06
- Earliest claimed: 2012-03-01
- Assignees: NLT Technologies, Ltd.
- Applicants: NLT Technologies, Ltd.
- Inventors: Shinichi Nishida; Hidenori Ikeno; Hideki Ito; Mitsuhiro Sugimoto
- Web page: https://patentgrep.com/patent/US9436024B2

## CPC

- G02F 1/13306: {Circuit arrangements or driving methods for the control of single liquid crystal cells (G02F1/132, G02F1/133382 take precedence)}
- G02F 1/13363: Birefringent elements, e.g. for optical compensation
- G02F 1/133634: {the refractive index Nz perpendicular to the element surface being different from in-plane refractive indices Nx and Ny, e.g. biaxial or with normal optical axis}
- G02F 1/133753: {with different alignment orientations or pretilt angles on a same surface, e.g. for grey scale or improved viewing angle}
- G02F 1/134363: {for applying an electric field parallel to the substrate, i.e. in-plane switching [IPS]}
- G02F 1/137: characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering
- G02F 1/133631: {with a spatial distribution of the retardation value}
- G02F 1/133633: {using mesogenic materials}
- G02F 1/133757: {with different alignment orientations}
- G02F 2413/03: Number of plates being 3
- G02F 2413/07: All plates on one side of the LC cell
- G02F 2413/08: with a particular optical axis orientation
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS

## Abstract

To acquire a fine viewing angle property from oblique view fields in a lateral electric field type liquid crystal display device having liquid crystal initial alignment directions in two orthogonal directions. The absorption axis of the incident-side polarization plate and the absorption axis of the exit-side polarization plate are orthogonal to each other in both of the region I and the region II, and the liquid crystal layer, the in-cell retarder as an optical compensation layer, the A-plate, and the C-plate sandwiched therebetween are in parallel to either one of the absorption axes or orthogonal to the substrates. Therefore, the transmittance can be suppressed to be low and a fine black display can be acquired even when the display surface is viewed from the oblique view fields.

## Claims

### Claim 1

A lateral electric field type liquid crystal display device, comprising:
two transparent insulating substrates that are in parallel to each other;
a liquid crystal layer sandwiched between the substrates, the liquid crystal layer including liquid crystal which is aligned in a direction substantially in parallel to the substrates and to which a lateral electric field substantially in parallel to the substrates is applied;
a region I and a region II where initial alignment directions of the liquid crystal are orthogonal to each other;
two polarization plates having absorption axes that are orthogonal to each other and match either one of the initial alignment directions of the region I and the region II, one each of the polarization plates being disposed on outside of the two substrates, respectively;
a first optical compensation layer disposed between at least one of the substrates and the liquid crystal layer, the first optical compensation layer exhibiting uniaxial optical anisotropy in directions the same as the initial alignment directions of the liquid crystal in respectively overlapped region I and region II;
a second optical compensation layer disposed between one of the substrates and the polarization plate disposed on that substrate side, the second optical compensation layer exhibiting uniaxial optical anisotropy in a direction parallel to an absorption axis of the polarization plate; and
a third optical compensation layer disposed between the second optical compensation layer and the polarization plate closest to the second optical compensation layer, the third optical compensation layer exhibiting uniaxial optical anisotropy in a direction perpendicular to the substrate.

### Claim 2

A lateral electric field type liquid crystal display device, comprising:
two transparent insulating substrates that are in parallel to each other;
a liquid crystal layer sandwiched between the substrates, the liquid crystal layer including liquid crystal which is aligned in a direction substantially in parallel to the substrates and to which an electric field substantially in parallel to the substrates is applied;
a region I and a region II where initial alignment directions of the liquid crystal are orthogonal to each other;
two polarization plates having absorption axes that are orthogonal to each other and match either one of the initial alignment directions of the region I and the region II, one each of the polarization plates being disposed on outside of the two substrates, respectively;
a first optical compensation layer disposed between at least one of the substrates and the liquid crystal layer, the first optical compensation layer exhibiting uniaxial optical anisotropy in directions the same as the initial alignment directions of the liquid crystal in respectively overlapped region I and region II; and
a fourth optical compensation layer disposed between one of the substrates and the polarization plate disposed on that substrate side, the fourth optical compensation layer exhibiting biaxial optical anisotropy, wherein
a main axis of the fourth optical compensation layer is in a direction in parallel to an absorption axis of the polarization plate in a plane parallel to the substrate, in a direction perpendicular thereto, and in a direction perpendicular to the substrate.

### Claim 3 (depends on 1)

The lateral electric field type liquid crystal display device as claimed in claim 1, wherein:
the first optical compensation layer exhibits positive uniaxial refractive index anisotropy; and
sum of retardation of the first optical compensation layer and retardation of the liquid crystal layer is within a range of 500 to 600 nm.

### Claim 4 (depends on 1)

The lateral electric field type liquid crystal display device as claimed in claim 1, further comprising pixels each constituted with a plurality of sub-pixels, each of the sub-pixels having an individual color filter, wherein
sum of retardation of the first optical compensation layer and retardation of the liquid crystal layer in each of the sub-pixels is equivalent to a wavelength that is selected from a range of 90% or more from a peak of a transmittance spectrum of the color filter provided to the sub-pixel.

### Claim 5 (depends on 1)

The lateral electric field type liquid crystal display device as claimed in claim 1, wherein:
the first optical compensation layer exhibits negative uniaxial refractive index anisotropy; and
sum of retardation of the first optical compensation layer and retardation of the liquid crystal layer is within a range of −50 to 50 nm.

### Claim 6 (depends on 1)

The lateral electric field type liquid crystal display device as claimed in claim 1, wherein:
in the region I and the region II, directions of the lateral electric field are orthogonal to each other, and angles formed between the alignment directions of the liquid crystal and the directions of the lateral electric field are substantially the same.

### Claim 7 (depends on 2)

The lateral electric field type liquid crystal display device as claimed in claim 2, wherein:
the first optical compensation layer exhibits positive uniaxial refractive index anisotropy; and
sum of retardation of the first optical compensation layer and retardation of the liquid crystal layer is within a range of 500 to 600 nm.

### Claim 8 (depends on 2)

The lateral electric field type liquid crystal display device as claimed in claim 2, further comprising pixels each constituted with a plurality of sub-pixels, each of the sub-pixels having an individual color filter, wherein
sum of retardation of the first optical compensation layer and retardation of the liquid crystal layer in each of the sub-pixels is equivalent to a wavelength that is selected from a range of 90% or more from a peak of a transmittance spectrum of the color filter provided to the sub-pixel.

### Claim 9 (depends on 2)

The lateral electric field type liquid crystal display device as claimed in claim 2, wherein:
the first optical compensation layer exhibits negative uniaxial refractive index anisotropy; and
sum of retardation of the first optical compensation layer and retardation of the liquid crystal layer is within a range of −50 to 50 nm.

### Claim 10 (depends on 2)

The lateral electric field type liquid crystal display device as claimed in claim 2, wherein:
in the region I and the region II, directions of the lateral electric field are orthogonal to each other, and angles formed between the alignment directions of the liquid crystal and the directions of the lateral electric field are substantially the same.