Array substrate and liquid crystal display device including the same

• US 20040125262A1
• Filed: 12/18/2003
• Published: 07/01/2004
• Est. Priority Date: 12/26/2002
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Lee, Dong-Hoon, Cho, So-Haeng
• Granted Patent: US 7,268,839 B2
• Time in Patent Office: Days
• US Class Current: 349/43
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: H01L 27/124 with a particular composition, shape or layout of the wiring layers specially adapted to the circuit arrangement, e.g. scanning lines in LCD pixel circuits wiring structures per se H01L23/52
• CPC Class Codes: H01L 27/1296 adapted to increase the uniformity of device parameters

Abstract

An array substrate for a liquid crystal display device including a substrate, a gate electrode on the substrate, a first insulating layer on the gate electrode, an active layer on the first insulating layer and corresponding to the gate electrode, a source electrode over the active layer and overlapping an edge of the active layer, a drain electrode over the active layer and having an island shape, wherein the drain electrode entirely overlaps the gate electrode, a second insulating layer on the source and drain electrodes, and including a drain contact hole exposing the drain electrode, and a pixel electrode over the second insulating layer and connected to the drain electrode.

Claims

1. An array substrate for a liquid crystal display device, comprising:

a substrate;

a gate electrode on the substrate;

a first insulating layer on the gate electrode;

an active layer on the first insulating layer and corresponding to the gate electrode;

a source electrode over the active layer and overlapping an edge of the active layer and forming a first parasitic capacitance between the source electrode and gate electrode;

a drain electrode over the active layer and having an island shape, wherein the drain electrode is entirely on the gate electrode and forms a second parasitic capacitance between the drain electrode and gate electrode;

a second insulating layer on the source and drain electrodes, and including a drain contact hole exposing the drain electrode; and

a pixel electrode over the second insulating layer and connected to the drain electrode.

2. The array substrate according to claim 1, wherein the pixel electrode includes an extended portion covering the drain electrode, wherein a third parasitic capacitance is formed by the extended portion and the gate electrode.

3. The array substrate according to claim 2, wherein the extended portion contacts the drain electrode through the drain contact hole.

4. The array substrate according to claim 1, wherein the source electrode has an opening.

5. The array substrate according to claim 4, wherein the extended portion passes through the opening.

6. The array substrate according to claim 4, wherein the source electrode encloses the drain electrode.

7. The array substrate according to claim 1, wherein the source electrode partially overlaps the gate electrode.

8. The array substrate according to claim 1, wherein the second insulating layer is made of benzocyclobutene (BCB).

9. The array substrate according to claim 1, further comprising an ohmic contact layer between the active layer and the source and drain electrodes.

10. A liquid crystal display device, comprising:

first and second substrates facing and spaced apart from each other;

a gate electrode on an inner surface of the first substrate;

a first insulating layer on the gate electrode;

an active layer on the first insulating layer and corresponding to the gate electrode;

a source electrode over the active layer and overlapping an edge of the active layer;

a drain electrode over the active layer and having an island shape, wherein the drain electrode is entirely on the gate electrode, wherein the drain electrode is spaced apart from the source electrode;

a second insulating layer on the source and drain electrodes, and including a drain contact hole exposing the drain electrode;

a pixel electrode over the second insulating layer and connected to the drain electrode via the drain contact hole;

a black matrix on an inner surface of the second substrate;

a color filter layer on the black matrix;

a common electrode on the color filter layer; and

a liquid crystal layer between the pixel electrode and the common electrode.

11. The device of claim 10, wherein the source electrode has an opening.

12. The device according to claim 11, wherein the source electrode encloses the drain electrode.

13. The device according to claim 10, wherein the pixel electrode includes an extended portion covering the drain electrode.

14. The device according to claim 13, wherein the extended portion contacts the drain electrode through the drain contact hole.

15. The device according to claim 13, wherein the extended portion passes through an opening of the source electrode.