Liquid crystal display comprising a dielectric layer having a first opening surrounding a patterned structure and exposing a portion of a first pixel electrode and a second pixel electrode formed on the dielectric layer

• US 7,940,359 B2
• Filed: 04/25/2007
• Issued: 05/10/2011
• Est. Priority Date: 04/25/2007
• Status: Active Grant

• Current Assignee: AUO Corp.
• Original Assignee: AU Optronics Corporation
• Inventors: Lee, Seok-Lyul
• Primary Examiner(s): Robinson; Mark A
• Assistant Examiner(s): Kim; Dennis Y
• Application Number:
  US11/739,901
• Publication Number:
  US 20080266480A1
• Time in Patent Office: 1,476 Days
• Field of Search: 349/39, 349/147, 349/129, 349/130, 349/138
• US Class Current: 349/138
• CPC Class Codes: G02F 1/134309 characterised by their geometrical arrangement
• CPC Class Codes: G02F 1/134381 Hybrid switching mode, i.e. for applying an electric field with components parallel and orthogonal to the substrates
• 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

Abstract

A liquid crystal display (LCD) device. In one embodiment, the LCD device includes a first substrate and a second substrate positioned apart from the first substrate, a liquid crystal layer positioned between the first substrate and the second substrate, and a plurality of pixels formed on the first substrate. Each pixel has a first pixel electrode formed on the first substrate, a second pixel electrode formed on an dielectric layer, wherein the dielectric layer is formed on the first pixel electrode to have a patterned structure with an opening exposing a portion of the first pixel electrode such that the second pixel electrode is connected to the first pixel electrode through the one opening; and an auxiliary common electrode formed on the dielectric layer and distantly surrounding the second pixel electrode.

Claims

1. A liquid crystal display (LCD) device, comprising:

a first substrate and a second substrate positioned apart to define a cell gap therebetween;

a liquid crystal layer positioned in the cell gap between the first substrate and the second substrate;

a common electrode formed between the second substrate and the liquid crystal layer; and

a plurality of scanning lines arranged in a first direction on the first substrate and a plurality of data lines arranged crossing the plurality of scanning lines in a second direction that is substantially perpendicular to the first direction on the first substrate to define a plurality of pixels therewith, each pixel comprising;

a first dielectric layer formed on the first substrate;

a first pixel electrode formed on the first dielectric layer, the first pixel electrode defining a first electrode area;

a second dielectric layer formed at least on the first pixel electrode, the second dielectric layer having a first opening and a patterned structure with a second opening, the first opening surrounding the patterned structure and exposing a portion of the first pixel electrode;

a second pixel electrode formed on the pattern structure of the second dielectric layer, the second pixel electrode being electrically connected to the first pixel electrode through the second opening and positioned over the first pixel electrode, the second pixel electrode defining a second electrode area less than the first electrode area; and

an auxiliary common electrode formed on the second dielectric layer, distantly surrounding the second pixel, wherein the common electrode and the auxiliary common electrode have a same electric potential.

2. The LCD device of claim 1, wherein the first pixel electrode is formed of indium zinc oxide (IZO), amorphous indium tin oxide (ITO), poly ITO, or any combination of them.

3. The LCD device of claim 2, wherein the first pixel electrode has a thickness in the range of about 0.04-3.0 μ

m.

4. The LCD device of claim 1, wherein the second pixel electrode has a geometric shape of a circle, rectangle, or polygon.

5. The LCD device of claim 1, wherein the second pixel electrode and the auxiliary common electrode define a distance therebetween, which is greater than the cell gap.

6. The LCD device of claim 1, wherein the second pixel electrode and the auxiliary common electrode are formed of transparent or opaque conductivity material.

7. The LCD device of claim 1, wherein the patterned structure comprises a geometric shape of a circle, rectangle, polygon, star, or cross.

8. The LCD device of claim 1, wherein the second dielectric layer is formed of SiNx, SiOx, SiON or insulating organic material.

9. The LCD device of claim 8, wherein the second dielectric layer has a thickness in the range of about 0.1-10.0 μ

m.

10. The LCD device of claim 1, wherein the liquid crystal layer comprises liquid crystals having a negative dielectric anisotropy.

11. The LCD device of claim 10, wherein the liquid crystals are selected such that a product of the refractive index δ

_n of the liquid crystals and the cell gap is in a range of about 0.15-0.60 um.

12. The LCD device of claim 10, wherein the liquid crystals are aligned homeotropically to the first substrate and the second substrate in the absence of an electric field therein.

13. The LCD device of claim 1, wherein when a voltage is applied to one of the first pixel electrode and the common electrode, a corresponding voltage difference is established therebetween, and an oblique electric field is generated in the liquid crystal layer.

14. The LCD device of claim 13, wherein the generated oblique electric field drives the liquid crystals of the liquid crystal layer in desired directions.

15. The LCD device of claim 13, wherein the common electrode and the auxiliary common electrode have an identical, first electric potential, and the first pixel electrode and the second pixel electrode have an identical, second electric potential that is substantially different from the first electric potential.

16. A liquid crystal display (LCD) device, comprising:

a first substrate and a second substrate positioned apart from the first substrate;

a liquid crystal layer positioned between the first substrate and the second substrate;

a common electrode formed between the second substrate and the liquid crystal layer; and

a plurality of pixels formed on the first substrate, each pixel comprising;

a first pixel electrode formed on the first substrate, the first pixel electrode defining a first electrode area;

a dielectric layer formed at least on the first pixel electrode, the dielectric layer having a first opening and a patterned structure with a second opening, first opening surrounding the patterned structure and exposing a portion of the first pixel electrode;

a second pixel electrode formed on the patterned structure of the dielectric layer, the second pixel electrode being electrically connected to the first pixel electrode through the second opening and positioned over the first pixel electrode, the second pixel electrode defining a second electrode area less than the first electrode area; and

an auxiliary common electrode formed on the dielectric layer, distantly surrounding the second pixel electrode, wherein the common electrode and the auxiliary common electrode have a same electric potential.

17. The LCD device of claim 16, wherein the liquid crystal layer comprises a plurality of liquid crystals that are aligned homeotropically to the first substrate and the second substrate in the absence of an electric field therein.

18. The LCD device of claim 16, wherein in operation, the common electrode and the auxiliary common electrode have an identical, first electric potential, and the first pixel electrode and the second pixel electrode have an identical, second electric potential that is substantially different from the first electric potential.

19. The LCD device of claim 16, wherein the patterned structure comprises a geometric shape of a circle, rectangle, polygon, star, or cross.

25. The method of claim 19, wherein the first pixel electrode comprises indium zinc oxide (IZO), amorphous indium tin oxide (ITO), poly ITO, or any combination of them.

26. The method of claim 25, wherein the first pixel electrode has a thickness in the range of about 0.04-3.0 μ

m.

20. A method of manufacturing a liquid crystal display (LCD) device, comprising the steps of:

providing a first substrate;

forming a plurality of gate electrodes on the first substrate, each pair of adjacent gate electrodes defining a pixel area therebetween, the pixel area being adjacent to a switching area in which a corresponding gate electrode is formed;

forming a dielectric layer on the first substrate and the plurality of gate electrodes;

forming a semiconductor layer on the dielectric layer in each switching area;

forming an contact layer on the semiconductor layer, the contact layer having a first portion and a second portion separated from the first portion;

forming a first pixel electrode on the dielectric layer in each pixel area, the first pixel electrode defining a first electrode area therein;

forming a metal layer on the contact layer in each switching area, the metal layer having a first portion connected to a data line and a second portion separated from the first portion and connected to the pixel electrode layer in a corresponding pixel area;

forming a passivation layer on the metal layer in each switching area and the first pixel electrode in each pixel area, the passivation layer having a first opening and a patterned structure with at least one second opening formed in the pixel area, the first opening surrounding the patterned structure and exposing a portion of the first pixel electrode therein; and

forming a second pixel electrode and an auxiliary common electrode on the passivation layer in each pixel area, the second pixel electrode distantly surrounded by the auxiliary common electrode, the second pixel electrode being formed on the patterned structure and electrically connected to a corresponding first pixel electrode through the second opening and positioned directly over the first pixel electrode, the second pixel electrode defining a second electrode area less than the first electrode area;

positioning a second substrate apart from the first substrate, the second substrate having a common electrode; and

forming a liquid crystal layer between the first substrate and the second substrate, and the common electrode being positioned between the second substrate and the liquid crystal layer.

21. The method of claim 20, wherein the semiconductor layer comprises amorphous silicon or poly silicon.

22. The method of claim 20, wherein the contact layer comprises doped amorphous silicon or doped poly silicon.

23. The method of claim 22, wherein the doped amorphous silicon or doped poly silicon is doped poly silicon and comprises n⁺ doped p-Si or p⁺doped p-Si.

24. The method of claim 22, wherein the doped amorphous silicon or doped poly silicon is doped amorphous silicon comprises n⁺doped a-Si or p⁺doped a-Si.

27. The method of claim 20, wherein the patterned structure comprises a geometric shape of a circle, rectangle, polygon, star, or cross.

28. The method of claim 20, wherein the patterned structure of the passivation layer in each pixel area is formed with an etching process.

29. The method of claim 20, wherein the passivation layer comprises SiNx, SiOx, SiON or insulating organic material and has a thickness in the range of about 0.1-10.0 μ

m.

30. The method of claim 20, wherein each of the second pixel electrode and auxiliary common electrode comprises transparent or opaque conductivity material.

31. A method of manufacturing a liquid crystal display (LCD) device, comprising the steps of:

providing a first substrate and a second substrate positioned apart from the first substrate, and the second substrate having a common electrode;

forming a plurality of switch members on the first substrate, each pair of adjacent switch members defining a pixel area therebetween;

forming a first pixel electrode on the first substrate in each pixel area, the first pixel electrode defining a first electrode area and being connected to a corresponding switch member;

forming an insulation layer passivating the plurality of switch members and the first pixel electrode in each pixel area, the insulation layer having a first opening and a patterned structure with at least one second opening formed in the pixel area, the first opening surrounding the patterned structure and exposing a portion of the first pixel electrode;

forming a second pixel electrode and an auxiliary common electrode on the insulation layer in each pixel area, the second pixel electrode distantly surrounded by the auxiliary common electrode, the second pixel electrode being formed on the patterned structure and electrically connected to the first pixel electrode through the second opening and positioned over the first pixel electrode, the second pixel electrode defining a second electrode area less than the first electrode area; and

forming a liquid crystal layer between the first substrate and the second substrate and the common electrode being positioned between the second substrate and the liquid crystal layer.

32. The method of claim 31, wherein the patterned structure comprises a geometric shape of a circle, rectangle, polygon, star, or cross.

33. The method of claim 31, wherein the switch member comprises a thin film transistor (TFT) having a gate electrode formed on the substrate and a source electrode connected to a data line and a drain electrode connected to the first pixel electrode, respectively.

34. The method of claim 31, wherein the first pixel electrode comprises indium zinc oxide (IZO), amorphous indium tin oxide (ITO), poly ITO, or any combination of them.

35. The method of claim 31, wherein the second pixel electrode and auxiliary common electrode comprise a conductive material.