Liquid crystal display device

• US 20080100787A1
• Filed: 10/24/2007
• Published: 05/01/2008
• Est. Priority Date: 10/31/2006
• Status: Active Grant

• Current Assignee: Japan Display West Incorporated (Japan Display Incorporated)
• Original Assignee: Epson Imaging Devices Corporation (Seiko Group)
• Inventors: Onogi, Tomohide, Segawa, Yasuo, Yata, Tatsuya
• Granted Patent: US 7,982,840 B2
• Time in Patent Office: Days
• US Class Current: 349/141
• CPC Class Codes: G02F 1/134363 for applying an electric field parallel to the substrate, i.e. in-plane switching [IPS]
• CPC Class Codes: G02F 1/134372 for fringe field switching [FFS] where the common electrode is not patterned
• CPC Class Codes: G02F 1/13685 Top gates

Abstract

A liquid crystal display device includes a substrate, an insulating layer, an upper electrode layer, and a lower electrode layer. The upper electrode layer and the lower electrode layer are formed on the same the substrate via the insulating layer. A plurality of openings are formed in the upper electrode layer and arranged parallel to each other so that an electric field is passed therethrough. Liquid crystal molecules are driven by applying voltage between the upper electrode layer and the lower electrode layer. A minor axis of each of the openings has a width in a range in which a V-T curve, which represents a relationship between voltage and transmittance ratio, does not shift with variation in the width of the minor axis.

Claims

1. A liquid crystal display device, comprising:

a substrate;

an insulating layer;

an upper electrode layer; and

a lower electrode layer, wherein the upper electrode layer and the lower electrode layer are formed above a same major surface of the substrate with the insulating layer therebetween, wherein a plurality of openings are formed in the upper electrode layer and arranged parallel to each other so that an electric field is passed therethrough, wherein liquid crystal molecules are driven by applying voltage between the upper electrode layer and the lower electrode layer, wherein

a minor axis of each of the openings has a width in a range in which a V-T curve, which represents a relationship between voltage and transmittance ratio, does not shift with variation in the width of the minor axis.

2. The liquid crystal display device according to claim 1, wherein each of the openings is a slit opening that opens with a closed shape.

3. The liquid crystal display device according to claim 1, wherein the plurality of openings form a comb-shaped opening such that one ends of the openings are connected to each other.

4. The liquid crystal display device according to claim 1, wherein the upper electrode layer is a common electrode layer.

5. The liquid crystal display device according to claim 1, wherein the upper electrode layer is a pixel electrode layer.

6. A liquid crystal display device, comprising:

a substrate;

an insulating layer;

an upper electrode layer; and

a lower electrode layer, wherein the upper electrode layer and the lower electrode layer are formed above a same major surface of the substrate with the insulating layer therebetween, wherein a plurality of openings are formed in the upper electrode layer and arranged parallel to each other so that an electric field is passed therethrough, wherein liquid crystal molecules are driven by applying voltage between the upper electrode layer and the lower electrode layer, wherein

where an electrode width, which corresponds to a distance between the adjacent openings, is L and the width of a minor axis of each of the openings is S, and when the sum of L and S is equal to or below 10 μ

m, the electrode width L is equal to or above 2.5 μ

m and the width S of the minor axis of each of the openings is equal to or above 4.0 μ

m.

7. The liquid crystal display device according to claim 6, wherein each of the openings is a slit opening that opens with a closed shape.

8. The liquid crystal display device according to claim 6, wherein the plurality of openings form a comb-shaped opening such that one ends of the openings are connected to each other.

9. The liquid crystal display device according to claim 6, wherein the upper electrode layer is a common electrode layer.

10. The liquid crystal display device according to claim 6, wherein the upper electrode layer is a pixel electrode layer.

11. A liquid crystal device, comprising:

a substrate;

an upper electrode layer formed on the substrate;

an insulating layer formed between the upper electrode and the substrate; and

a lower electrode layer formed between the insulating layer and the substrate,

the upper electrode layer being formed with a plurality of openings arranged parallel to each other, the plurality of openings allowing passage of an electric field and applying a voltage between the upper electrode layer and the lower electrode layer, the voltage driving liquid crystal molecules,

each of the openings having a minor axis with a width in a range in which a V-T curve, which represents a relationship between voltage and transmittance ratio, does not shift with variation in the width of the minor axis.

12. A liquid crystal device, comprising:

a substrate;

an upper electrode layer formed on the substrate;

an insulating layer formed between the upper electrode and the substrate; and

a lower electrode layer formed between the insulating layer and the substrate,

the upper electrode layer being formed with a plurality of openings arranged parallel to each other, the plurality of openings allowing passage of an electric field and applying a voltage between the upper electrode layer and the lower electrode layer, the voltage driving liquid crystal molecules,

the upper electrode layer having an electrode width that corresponds to a distance between adjacent openings,

each of the openings having a minor axis with an axis width, and

when a sum of the electrode width and the axis width is equal to or less than 10 μ

m, the electrode width L being equal to or greater than 2.5 μ

m, and the axis width being equal to or greater than 4.0 μ

m.