Liquid crystal display device

Abstract

The liquid crystal display has first and second substrates having electrodes and a pretilt angle of 88.5° to 89.5°, a liquid crystal layer, having a thickness of d and made of liquid crystal molecule material which has a twist structure at a twist angle of 160° to 240° in a voltage application state, the liquid crystal layer containing chiral material having a pitch of p, where d/p is 0.2 to 0.74, a first polarizer disposed facing the first substrate, the first polarizer having as a transmission axis direction a first direction, a second polarizer disposed facing the second substrate, the second polarizer having as a transmission axis direction a second direction having an angle of 85° to 95° relative to the first direction, and an optical anisotropic plate disposed at least one of between the first substrate and first polarizer and between the second substrate and second polarizer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph showing simulation results.

FIG. 2 is a graph showing simulation results.

FIG. 3 is a schematic broken perspective view showing an example of the internal structure of LCD used for a simulation target.

FIG. 4 is a graph showing simulation results.

FIG. 5 is a graph showing simulation results.

FIG. 6 is a graph showing simulation results.

FIG. 7 is a schematic broken perspective view of a mono-domain pretilt vertical alignment type LCD.

FIG. 8 is a schematic broken perspective view of a mono-domain pretilt vertical alignment type LCD having a viewing angle compensation plate.

FIG. 9 is a graph showing an observation polar angle dependency of an optical transmittance when a viewing angle compensation plate is used (the vertical alignment type LCD shown in FIG. 8) and when the viewing angle compensation plate is not used (the vertical alignment type LCD shown in FIG. 7).

FIGS. 10A to 10E are schematic broken perspective views of LCD.

FIG. 11 is a graph showing the relation between a retardation and an optical transmittance.

FIG. 12 is a graph showing the relation between a twist angle and an optical transmittance at a polar angle of 50°.

Claims

1. A liquid crystal display comprising: a first substrate provided with an electrode pattern and subjected to an alignment process of giving a pretilt angle of 88.5° or larger and 89.5° or smaller;a second substrate disposed generally in parallel to said first substrate, provided with an electrode pattern and subjected to an alignment process of giving a pretilt angle of 88.5° or larger and 89.5° or smaller;a liquid crystal layer squeezed between said first substrate and said second substrate, having a thickness of d and made of liquid crystal molecule material which is aligned generally perpendicular to said first substrate and said second substrate in a no voltage application state in accordance with the alignment processes subjected to said first substrate and said second substrate and has a twist structure at a twist angle of 160° or larger and 240° or smaller in a voltage application state, said liquid crystal layer containing chiral material having a chiral pitch of 2, where d/p is 0.2 or larger and 0.74 or smaller;a first polarizer disposed facing a plane of said first substrate on a side opposite to said liquid crystal layer, said first polarizer having as a transmission axis direction a first direction;a second polarizer disposed facing a plane of said second substrate on a side opposite to said liquid crystal layer, said second polarizer having as a transmission axis direction a second direction having an angle of 85° or larger and 95° or smaller relative to said first direction as viewed along a normal direction of said first substrate and said second substrate; andan optical anisotropic plate having an in-plane direction generally in parallel to said first and second polarizers and disposed at least one of between said first substrate and said first polarizer and between said second substrate and said second polarizer.

2. The liquid crystal display according to claim 1, wherein a retardation Δn·d, which is a product of a birefringence Δn of said liquid crystal molecule material and the thickness d of said liquid crystal layer, is 580 nm or larger.

3. The liquid crystal display according to claim 1, wherein said optical anisotropic plate has negative uniaxial optical anisotropy, and is disposed at least one of between said first substrate and said first polarizer and between said second substrate and said second polarizer.

4. The liquid crystal display according to claim 1, wherein said optical anisotropic plate comprises two positive uniaxial optical anisotropic plates disposed in a state that delay phase axes are mutually perpendicular, and is disposed at least one of between said first substrate and said first polarizer and between said second substrate and said second polarizer.

5. The liquid crystal display according to claim 1, wherein said optical anisotropic plate has negative biaxial optical anisotropy, and is disposed at least one of between said first substrate and said first polarizer and between said second substrate and said second polarizer.

6. The liquid crystal display according to claim 1, wherein said optical anisotropic plate comprises an optical anisotropic plate having positive uniaxial anisotropy and an optical anisotropic plate having negative uniaxial anisotropy, and is disposed at least one of between said first substrate and said first polarizer and between said second substrate and said second polarizer.

7. The liquid crystal display according to claim 1, wherein said optical anisotropic plate comprises an optical anisotropic plate having negative biaxial anisotropy and an optical anisotropic plate having negative uniaxial anisotropy, and is disposed at least one of between said first substrate and said first polarizer and between said second substrate and said second polarizer.