LIQUID CRYSTAL DISPLAY HAVING WIDE VIEWING ANGLE

• US 20080273154A1
• Filed: 06/27/2008
• Published: 11/06/2008
• Est. Priority Date: 05/19/1998
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Song, Jang-Kun, Lee, Hea-Ri, Kim, Kyeong-Hyeon, Lee, Kye-Hun
• Granted Patent: US 7,787,087 B2
• Time in Patent Office: Days
• US Class Current: 349/139
• CPC Class Codes: G02F 1/133528 Polarisers
• CPC Class Codes: 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
• CPC Class Codes: G02F 1/133707 Structures for producing distorted electric fields, e.g. bumps, protrusions, recesses, slits in pixel electrodes
• CPC Class Codes: G02F 1/133742 for homeotropic alignment
• CPC Class Codes: G02F 1/133753 with different alignment orientations or pretilt angles on a same surface, e.g. for grey scale or improved viewing angle
• CPC Class Codes: G02F 1/133757 with different alignment orientations
• CPC Class Codes: G02F 1/1343 Electrodes reflective electrodes G02F1/133553
• CPC Class Codes: G02F 1/134309 characterised by their geometrical arrangement
• CPC Class Codes: G02F 1/134336 Matrix
• CPC Class Codes: G02F 1/13439 characterised by their electrical, optical, physical properties; materials therefor; method of making
• CPC Class Codes: G02F 1/13712 the liquid crystal having negative dielectric anisotropy
• CPC Class Codes: G02F 1/1393 the birefringence of the liquid crystal being electrically controlled, e.g. ECB-, DAP-, HAN-, PI-LC cells G02F1/1396, G02F1/141 take precedence
• CPC Class Codes: G02F 1/1396 the liquid crystal being selectively controlled between a twisted state and a non-twisted state, e.g. TN-LC cell G02F1/141 takes precedence
• CPC Class Codes: G02F 2201/121 common or background

Abstract

A tetragonal ring shape aperture is formed in the common electrode on one substrate and a cross shape aperture is formed at the position corresponding to the center of the tetragonal ring shape aperture in the pixel electrode on the other substrate. A liquid crystal layer between two electrodes are divided to four domains where the directors of the liquid crystal layer have different angles when a voltage is applied to the electrodes. The directors in adjacent domains make a right angle. The tetragonal ring shape aperture is broken at midpoint of each side of the tetragon, and the width of the aperture decreases as goes from the bent point to the edge. Wide viewing angle is obtained by four domains where the directors of the liquid crystal layer indicate different directions, disclination is removed and luminance increases.

Claims

1-22. -22. (canceled)

23. A liquid crystal display comprising:

a first substrate;

a first electrode formed on the substrate and having a plurality of first domain dividers;

a second substrate facing the first substrate;

a second electrode formed corresponding to the first electrode on the second substrate and having a plurality of second domain dividers, and

a liquid crystal layer between the first and the second substrates;

wherein at least one of the second domain dividers comprises a main body and a branch extending from the main body along an edge of the first electrode and

wherein the long axes of liquid crystal molecules in the liquid crystal layer are aligned perpendicular to the substrates in the state that no voltage is applied to the electrodes.

24. The liquid crystal display of claim 23, wherein the main body and the branch form an obtuse angle.

25. The liquid crystal display of claim 23, wherein either the first domain dividers or the second domain dividers are apertures.

26. A liquid crystal display comprising:

a first substrate having an inner surface and an outer surface;

a first electrode formed on the inner surface of said first substrate and having a plurality of first domain dividers;

a second substrate facing the first substrate and having an inner surface and an outer surface;

a second electrode formed corresponding to the first electrode on the inner surface of the second substrate having a plurality of second domain dividers;

a plurality of domains formed by the first domain dividers and the second domain dividers, wherein the number of average axial directions of liquid crystal in a group of adjacent domains is four;

a liquid crystal layer between the first and the second substrates;

a first polarizer attached on the outer surface of said first substrate; and

a second polarizer attached on the outer surface of said second substrate,

wherein the average axial direction of each domain is tilted at an angel of 45°

±

10°

with respect to polarizing directions of the first polarizer and the second polarizer and

wherein the long axes of liquid crystal molecules in the liquid crystal layer are aligned perpendicular to the substrates in the state that no voltage is applied to the electrodes.

27. The liquid crystal display of claim 26, wherein either the first domain dividers or the second domain dividers are apertures.