Samsung Electronics Co., Ltd.

Samsung Display Co., Ltd.

Jian-Min Chen

Jae-Jin Lyu

Hea-Ri Lee

Kyeong-Hyeon Kim

Kyeong Hyeon Kim

Kycong-Hyeon Kim

A liquid crystal display comprises two parallel spaced substrates and a liquid crystal layer with negative dielectric anisotropy interposed between the substrates. The ratio d/p, the cell gap d between the substrates to the pitch p of the liquid crystal layer, is equal to or less than 0.3, and the retardation value &#x394;n*d may be in the range of 0.25-0.4. In absence of electric field, the liquid crystal molecules are arranged vertically to the substrates, and when the sufficient electric field is applied, the liquid crystal molecules are parallel to the substrates and twisted by 90&#xb0; from one substrate to the other.

Liquid crystal displays

Apertures are formed in the common electrode or in the pixel electrode of a liquid crystal display to form a fringe field. Storage capacitor electrodes are formed at the position corresponding to the apertures to prevent the light leakage due to the disclination caused by the fringe field. The apertures extend horizontally, vertically or obliquely. The apertures in adjacent pixel regions may have different directions to widen the viewing angle.

Liquid crystal display having wide viewing angle

Liquid crystal display

A liquid crystal display comprises two parallel spaced substrates and a liquid crystal layer with negative dielectric anisotropy interposed between the substrates. The ratio d/p, the cell gap d between the substrates to the pitch p of the liquid crystal layer, is equal to or less than 0.3, and the retardation value &#x394;n*d may be in the range of 0.25-0.4. In absence of electric field, the liquid crystal molecules are arranged vertically to the substrates, and when the sufficient electric field is applied, the liquid crystal molecules are parallel to the substrates and twisted by 90&#xb0; from one substrate to the other. To the outer surface of a liquid crystal cell having a liquid crystal material with a negative dielectric anisotropy, a combination of a-plate, c-plate or biaxial compensation films is attached. The direction having the largest refractive index of the a-plate or the biaxial film is parallel or perpendicular to the polarizing direction of adjacent polarizer. The difference between the summation of the retardation (n&#x2212;n)*d of the a-plate, the c-plate and the biaxial films and the polarizers, and the retardation due to birefringence of the liquid crystal cell is equal to or less than 15% of the retardation due to birefringence of the liquid crystal cell. The retardation (n&#x2212;n)*d of the a-plate or the biaxial film is 0-100 nm. n, nand nare the refractive indices of the x, y and z axes respectively when the z axis is perpendicular to the surface of the liquid crystal cell, the x axis is in the surface of the liquid crystal cell and having the largest refractive index of the a-plate or the biaxial film and the y axis is in same plane as the x axis and perpendicular to the x axis, and d is the thickness of the film.

Apertures are formed in the common electrode or in the pixel electrode of a liquid crystal display to form a fringe field. Storage capacitor electrodes are formed at the position corresponding to the apertures to prevent the light leakage due to the disclination caused by the fringe field. The apertures extend horizontally vertically or obliquely. The apertures in adjacent pixel regions may have different directions to widen the viewing angle.

Liquid crystal display devices include a vertically aligned liquid crystal cell having first and second surfaces that extend opposite each other and contain a liquid crystal material therein having negative dielectric anisotropy. First and second polarizers are attached to the first and second surfaces of the liquid crystal cell, respectively. A first a-plate compensation film and a first c-plate compensation film are provided. These films are disposed between the first surface of the liquid crystal cell and the first polarizer. The direction having a largest refractive index in the first a-plate compensation film is parallel to or perpendicular to a polarizing direction of the first polarizer. Moreover, a difference between a summation of a retardation (n&#x2212;n)&#xd7;dof the first a-plate compensation film, a retardation (n&#x2212;n)&#xd7;dof the first c-plate compensation film and a retardation of the first and the second polarizers and a retardation due to birefringence of the liquid crystal cell is equal to or less than 15% of the retardation value due to birefringence of the liquid crystal cell.

Liquid crystal display devices having wide viewing angle and improved contrast ratio

Liquid crystal display devices include a vertically aligned liquid crystal cell having first and second surfaces that extend opposite each other and contain a liquid crystal material therein having negative dielectric anisotropy. First and second polarizers are attached to the first and second surfaces of the liquid crystal cell, respectively. A first a-plate compensation film and a first c-plate compensation film are provided. These films are disposed between the first surface of the liquid crystal cell and the first polarizer. The direction having a largest refractive index in the first a-plate compensation film is parallel to or perpendicular to a polarizing direction of the first polarizer. Moreover, a difference between a summation of a retardation (n &minus;n )&times;d of the first a-plate compensation film, a retardation (n &minus;n )&times;d of the first c-plate compensation film and a retardation of the first and the second polarizers and a retardation due to birefringence of the liquid crystal cell is equal to or less than 15% of the retardation value due to birefringence of the liquid crystal cell.

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Kyungki-do, South Korea

Jian-Min Chen