Liquid crystal display device

• US 5,737,051 A
• Filed: 11/06/1996
• Issued: 04/07/1998
• Est. Priority Date: 09/18/1992
• Status: Expired due to Term

• Current Assignee: Panasonic Liquid Crystal Display Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Hitachi, Ltd.
• Inventors: Ohta, Masuyuki, Sasaki, Tohru, Kondo, Katsumi, Kawachi, Genshiro, Abe, Hidetoshi, Suzuki, Kenkichi, Terao, Hiromu, Ohwada, Junichi
• Primary Examiner(s): Gross, Anita Pellman
• Assistant Examiner(s): PARKER, KENNETH
• Application Number:
  US08/744,451
• Time in Patent Office: 517 Days
• Field of Search: 349/123, 349/19, 349/138, 349/39, 349/42, 349/136, 349/141, 349/139, 349/143
• US Class Current: 349/149
• 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 1/136213 Storage capacitors associated with the pixel electrode
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: G02F 2201/122 having a particular pattern
• CPC Class Codes: G02F 2201/128 field shaping

Abstract

The liquid crystal display device has a plurality of pixel elements, the optical transmissivity of which is varied by suitable electrical signals. The liquid crystal display device has electrodes which apply electric fields to a liquid crystal layer, the electric fields having components in a direction generally parallel to the liquid crystal layer. Each pixel element has at least one pixel electrode which extends in a common direction as signal electrodes and common electrodes which extend over several pixel elements. The common electrodes may be on the same side of the liquid crystal layer as the pixel and signal electrodes, or they may be on opposite sides. Each pixel may have two pixel electrodes with the signal electrode therebetween and there are then a pair of common electrodes with the pixel electrodes therebetween. The common electrodes may be common to adjacent pixel elements. The pixel electrodes and the common electrodes may be separated by an insulating film.

Claims

1. A liquid crystal display device including:

a pair of substrates;

a liquid crystal layer interposed between said pair of substrates;

common electrode lines formed on one substrate of said pair of substrates;

pixel electrode lines formed on said one substrate and disposed between said common electrode lines;

a nonconductive film in contact with said liquid crystal layer; and

a color filter formed on said nonconductive film;

wherein one surface of said nonconductive film adjacent to said color filter flattens said color filter and another surface of said nonconductive film adjacent to said liquid crystal layer controls an orientation of liquid crystal molecules of said liquid crystal layer; and

wherein an electric field is generated in said liquid crystal layer by applying a voltage between said pixel electrode lines and said common electrode lines.

2. A liquid crystal display device according to claim 1, wherein said nonconductive film is a single layer film.

3. A liquid crystal display device according to claim 1, wherein said nonconductive film is an organic polymer.

4. A liquid crystal display device according to claim 3, wherein said nonconductive film includes a polyimide.

5. A liquid crystal display device according to claim 4, wherein said nonconductive film includes an epoxy resin.

6. A liquid crystal display device according to claim 1, wherein a pretilt angle of liquid crystal molecules of said liquid crystal layer with respect to said one substrate is not more than 4°

.

7. A liquid crystal display device according to claim 1, wherein a dielectric constant anisotropy of said liquid crystal layer is positive, and an absolute value of an angle between components of said electric field in a direction parallel to said one substrate and a direction of orientation of liquid crystal molecules on said pair of substrates is less than 90°

but not less than 45°

.

8. A liquid crystal display device according to claim 1, wherein a dielectric constant anisotropy of said liquid crystal layer is negative, and an absolute value of an angle between components of said electric field in a direction parallel to said one substrate and direction of orientation of liquid crystal molecules on said pair of substrates is less than 45°

, but not less than 0°

.

9. A liquid crystal display device according to claim 1, wherein a product of a thickness of said liquid crystal layer and a refractive index anisotropy of said liquid crystal layer is between 0.21 μ

m and 0.36 μ

m.

10. A liquid crystal display device comprising:

a pair of substrates;

a liquid crystal layer interposed between said pair of substrates;

signal electrode lines and scanning electrode lines formed on one substrate of said pair of substrates and crossing each other in a matrix form, wherein a plurality of pixels are formed by adjoining said signal electrode lines and said scanning electrode lines;

wherein each pixel of said pixels comprises;

a semiconductor switching element formed proximate to a crossing point between a corresponding signal electrode line and a scanning electrode line;

a plurality of common electrode lines formed on said one substrate and having a connection portion connecting one of said plurality of common electrode lines to another of said plurality of over more than one of said plurality of pixels; and

at least one pixel electrode line formed on said one substrate, said at least one pixel electrode line being connected to said semiconductor switching element and disposed between said plurality of common electrode lines;

wherein two common electrode lines of said plurality of common electrode lines are disposed adjacent to one of said signal electrode lines so that said one of said signal electrode lines is disposed between said two common electrode lines.

11. A liquid crystal display device comprising:

a pair of substrates;

a liquid crystal layer interposed between said pair of substrates;

signal electrode lines and scanning electrode lines formed on one of said pair of substrates and crossing each other in a matrix form, wherein a plurality of pixels are formed by adjoining said signal electrode lines and said scanning electrode lines;

wherein each pixel of said pixels comprises;

a semiconductor switching element formed proximate to a crossing point between a corresponding signal electrode line and a scanning electrode line;

at least one common electrode line of a plurality of common electrode lines formed on said one substrate and having a connection portion connecting one of said plurality of common electrode lines to another of said plurality of over more than one of said plurality of pixels; and

at least one pixel electrode line formed on said one substrate, said at least one pixel electrode line being connected to said semiconductor switching element and disposed between said plurality of common electrode lines;

wherein at least one of said plurality of common electrode lines is disposed closer to one of said signal electrode lines than to said at least one pixel electrode line within said pixel so that said one of said signal electrode lines is disposed between two of said plurality of common electrode lines.

12. A liquid crystal display device including:

a pair of substrates;

a liquid crystal layer interposed between said pair of substrates;

signal electrode lines and scanning electrode lines formed on said one substrate and crossing each other in a matrix form, wherein a plurality of pixels are formed by adjoining said signal lines and said scanning lines;

wherein each pixel of said pixels comprises;

a semiconductor switching element formed proximate to a crossing point of a corresponding signal electrode line and scanning electrode line;

a common electrode line of a plurality of common electrode lines formed on said one substrate and connected to another common electrode line of said plurality of common electrode lines over more than one of said plurality of pixels by a connection portion of said plurality of common electrode lines; and

a pixel electrode line formed on said one substrate and extending substantially in parallel to said common electrode line, said pixel electrode line being coupled to said semiconductor switching element, said pixel electrode line including at least first and second electrically connected portions;

wherein an electric field is generated in said liquid crystal layer by applying a voltage between said common electrode line and said pixel electrode line, at least one first portion of said pixel electrode line being disposed in overlapping relation to said connection portion of said common electrode lines and being insulated therefrom, and a capacitance being formed between said connection portion of said common electrode lines and said at least one first portion of said pixel electrode line.

13. A liquid crystal display device including:

a pair of substrates;

a liquid crystal layer interposed between said pair of substrates;

signal electrode lines and scanning electrode lines formed on said one substrate and cross each other in a matrix form, wherein a plurality of pixels are formed by adjoining said signal lines and said scanning lines;

wherein each pixel of said pixels comprises;

a semiconductor switching element formed proximate to a crossing point of a corresponding signal electrode line and scanning electrode line;

common electrode lines formed on said one substrate and connected to each other over more than one of said plurality of pixels by a connection portion of said common electrode lines;

at least one pixel electrode line formed on said one substrate and being disposed between said common electrode lines, said at least one pixel electrode line, being coupled to said semiconductor switching element, said at least one pixel electrode line including at least first and second electrically connected portions; and

at least one first portion of said at least one pixel electrode line being disposed in overlapping relation to said connection portion of said common electrode lines and being insulated therefrom, and a capacitance being formed between said connection portion of said common electrode lines and said at least one first portion of said at least one pixel electrode line.