In-plane switching LCD device

• US 20020063835A1
• Filed: 05/21/2001
• Published: 05/30/2002
• Est. Priority Date: 05/23/2000
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Philips LCD Company Limited (LG Display Co., Ltd.)
• Inventors: Kim, Ik-Soo
• Granted Patent: US 6,661,492 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 1/136209 Light shielding layers, e.g. black matrix, incorporated in the active matrix substrate, e.g. structurally associated with the switching element
• CPC Class Codes: G02F 1/136286 Wiring, e.g. gate line, drain line

Abstract

The present invention discloses an IPS LCD device. The IPS LCD device according to the present invention implements a plurality of transparent common and pixel electrodes. Since the plurality of common and pixel electrodes are made from the transparent material on the same plane, the IPS LCD device has a high aperture ratio, a high brightness quality, and therefore a low power consumption.

In another aspect, the IPS LCD device according to the present invention implements overlapped data line and outermost common electrode. To form the overlapped data line and outermost common electrode, an organic passivation layer is used such that cross talk between the data line and the outermost common electrode is prevented. Then, because the overlapped data line and outermost common electrode serve as a black matrix such that no black matrix is needed. Therefore, an aperture ratio of the IPS LCD device is further improved.

Claims

1. An in-plane switching liquid crystal display device comprising:

first and second substrates;

a gate line and a common line on the first substrate;

a data line perpendicular to the gate line;

a thin film transistor at a crossing portion of the gate and data lines, the thin film transistor having gate, source, and drain electrodes;

a first insulating layer on the gate line;

a second insulating layer on the first substrate, the second insulating layer having at least one contact hole;

a plurality of transparent common electrodes on the second insulating layer;

a plurality of transparent pixel electrodes on the second insulating layer;

a transparent auxiliary electrode on the second insulating layer and electrically connected with the drain electrode via the contact hole; and

a liquid crystal layer between the first and second substrates.

2. The device of claim 1, further comprising a capacitor electrode on the first insulating layer.

3. The device of claim 2, wherein the capacitor electrode is a same material as the source and drain electrodes.

4. The device of claim 2, wherein a respective first end of at least one of the pixel electrodes overlaps the capacitor electrode.

5. The device of claim 1, further comprising a transparent auxiliary common electrode on the second insulating layer.

6. The device of claim 5, wherein the auxiliary common electrode overlaps the common line.

7. The device of claim 5, wherein the auxiliary common electrode is electrically connected with the common line via the contact hole.

8. The device of claim 1, wherein the plurality of transparent common electrodes includes an outermost common electrode adjacent to the data line that overlaps a portion of the data line.

9. The device of claim 1, wherein the common and pixel electrodes are selected from a group consisting of indium tin oxide (ITO) and indium zinc oxide (IZO).

10. The device of claim 1, further comprising a black matrix on a same layer as the gate line.

11. The device of claim 1, wherein the second insulating layer is selected from a group consisting of silicon oxide (SiOx) and silicon nitride (SiNx).

12. The device of claim 1, wherein the second insulating layer is an organic material.

13. The device of claim 12, wherein the organic material is selected from a group consisting of benzocyclobutene (BCB) and acryl resin.

15. The method of claim 14, wherein a capacitor electrode is further formed on the first insulating layer in the step of patterning the first metal.

16. The method of claim 15, wherein a respective first end of at least one of the pixel electrodes overlaps the capacitor electrode.

17. The method of claim 14, wherein an auxiliary common electrode is further formed on the second insulating layer in the step of patterning the transparent conductive material.

18. The method of claim 17, wherein the auxiliary common electrode overlaps the common line.

19. The method of claim 17, wherein the auxiliary common electrode is electrically connected with the common line via the contact hole.

20. The method of claim 14, wherein an outermost common electrode adjacent to the data line overlaps a portion of the data line.

21. The method of claim 14, wherein the common and pixel electrodes are selected from a group consisting of indium tin oxide (ITO) and indium zinc oxide (IZO).

22. The method of claim 14, further comprising the step of forming a black matrix on the same layer as the gate line.

23. The method of claim 14, wherein the second insulating layer is selected from a group consisting of silicon dioxide (SiO₂) and silicon nitride (SiNx).

24. The method of claim 14, wherein the second insulating layer is an organic material.

25. The method of claim 24, wherein the organic material is selected from a group consisting of benzocyclobutene (BCB) and acryl resin.

26. The device of claim 1, wherein the plurality of transparent common electrodes includes an outermost common electrode adjacent to the data line such that an interval exists between the outermost common electrode and the data line.

27. The device of claim 26, further comprising a black matrix on the first substrate below the interval

28. The method of claim 14, wherein an interval is formed between an outermost one of the common electrodes, and further comprising the step of forming a black matrix on the substrate below the interval.

30. The in-plane switching liquid crystal display device of claim 29, wherein the pixel electrodes are transparent.

31. The in-plane switching liquid crystal display device of claim 30, wherein the pixel electrodes are formed of a material selected from the group consisting of indium tin oxide (ITO) and indium zinc oxide (IZO)

32. The in-plane switching liquid crystal display device of claim 29, wherein the common electrodes are transparent.

33. The in-plane switching liquid crystal display device of claim 32, wherein the common electrodes are formed of a material selected from the group consisting of indium tin oxide (ITO) and indium zinc oxide (IZO)

34. The in-plane switching liquid crystal display device of claim 29, further comprising an auxiliary common electrode on the second insulating layer, the auxiliary common electrode contacting respective first ends of the common electrodes and contacting the common line via a contact hole through the first and second insulating layers.

35. The in-plane switching liquid crystal display device of claim 29, further comprising an auxiliary pixel electrode contacting the pixel electrodes.

36. The in-plane switching liquid crystal display device of claim 29, further comprising a capacitor electrode electrically connected with the pixel electrodes.

38. The method of fabricating an in-plane switching liquid crystal display device of claim 37, wherein the common electrodes and the pixel electrodes form an alternating pattern.

39. The method of fabricating an in-plane switching liquid crystal display device of claim 37, wherein the pixel electrodes are transparent.

40. The method of fabricating an in-plane switching liquid crystal display device of claim 39, wherein the pixel electrodes are formed of a material selected from the group consisting of indium tin oxide (ITO) and indium zinc oxide (IZO)

41. The method of fabricating an in-plane switching liquid crystal display device of claim 37, wherein the common electrodes are transparent.

42. The method of fabricating an in-plane switching liquid crystal display device of claim 41, wherein the common electrodes are formed of a material selected from the group consisting of indium tin oxide (ITO) and indium zinc oxide (IZO)

43. The method of fabricating an in-plane switching liquid crystal display device of claim 37, further comprising forming an auxiliary electrode on the second insulating layer, the auxliary electrode contacting one of the source and drain electrodes through a contact hole.

44. The method of fabricating an in-plane switching liquid crystal display device of claim 37, further comprising forming an auxiliary common electrode on the second insulating layer, the auxiliary common electrode contacting respective first ends of the common electrodes and contacting the common line via a contact hole through the first and second insulating layers.

45. The method of fabricating an in-plane switching liquid crystal display device of claim 37, further comprising forming an auxiliary pixel electrode contacting the pixel electrodes.

46. The method of fabricating an in-plane switching liquid crystal display device of claim 37, further comprising forming a capacitor electrode electrically connected with the pixel electrodes.

14. A method of fabricating an IPS LCD device, the method comprising:

depositing and patterning a first metal on a substrate to form a common line and a gate line, the gate line including a gate electrode;

forming a first insulating layer to cover the first metal;

forming an active layer on the first insulating layer;

depositing and patterning a second metal on the first insulating layer to form a data line, a source electrode, and a drain electrode, the data line being perpendicular to the gate line;

forming a second insulating layer on an overall surface of the substrate to cover the second metal and the active layer, the second insulating layer having at least contact hole; and

depositing and patterning a transparent conductive material on the second insulating layer such that a plurality of common electrodes, an auxiliary electrode, and a plurality of pixel electrodes are formed on a same plane, wherein the auxiliary pixel electrode is electrically connected with the drain electrode via the contact hole.

29. An in-plane switching liquid crystal display device comprising:

a first substrate and a second substrate;

a gate line and a common line on the first substrate;

a data line perpendicular to the gate line;

a thin film transistor at a crossing point of the gate and data lines;

the thin film transistor including a source electrode, a drain electrode and a gate electrode;

a first insulating layer over the gate line;

a second insulating layer over the first substrate;

pixel electrodes on the second insulating layer;

common electrodes on the second insulating layer, wherein the common electrodes and the pixel electrodes form an alternating pattern, the common electrodes including an outermost common electrode adjacent to the data line; and

a liquid crystal layer between the first and second substrates,

wherein the outermost common electrode and the data line are on different layers and wherein a portion of the outermost common electrode overlaps the data line.

37. A method of fabricating an in-plane switching liquid crystal display device, comprising:

depositing and patterning a first metal on a first substrate to form a gate line and a common line on the first substrate, the gate line including a gate electrode;

forming a first insulating layer over the gate line;

forming an active layer on the first insulating layer;

depositing and patterning a second metal on the first insulating layer to form a data line perpendicular to the gate line and source and drain electrodes;

forming a second insulating layer over the first insulating, the second metal and the active layer, the second insulating layer having a contact hole;

depositing and patterning a conductive material on the second insulating layer to form pixel electrodes and common electrodes on the second insulating layer, wherein the common electrodes include an outermost common electrode adjacent to the data line; and

interposing a liquid crystal layer between the first substrate and a second substrate,

wherein the outermost common electrode and the data line are on different layers and wherein a portion of the outermost common electrode overlaps the data line.

47. An in-plane switching liquid crystal display device, comprising:

a first substrate and a second substrate;

a gate line and a common line on the first substrate;

a data line perpendicular to the gate line;

a thin film transistor including a source electrode, a drain electrode and a gate electrode;

an insulating layer on the thin film transistor, the insulating layer having a contact hole above one of the source electrode and the drain electrode;

a plurality of common electrodes on the insulating layer;

a plurality of pixel electrodes on the insulating layer;

an auxiliary electrode contacting the one of the source electrode and the drain electrode through the contact hole.