Liquid crystal display having overlapped pixel electrodes and method for fabricating the same

• US 6,226,057 B1
• Filed: 04/16/1998
• Issued: 05/01/2001
• Est. Priority Date: 04/18/1997
• Status: Expired due to Term

• Current Assignee: BOE HYDIS Technology Company Limited (SK Hynix Inc.)
• Original Assignee: Hyundai Electronics Industries Co. Ltd. (SK Hynix Inc.)
• Inventors: Lee, Deuk Su
• Primary Examiner(s): TON, MINH TOAN T
• Application Number:
  US09/061,053
• Time in Patent Office: 1,111 Days
• Field of Search: 349/38, 349/43, 349/139, 349/42
• US Class Current: 349/38
• CPC Class Codes: G02F 1/134336 Matrix
• 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 2201/123 pixel

Abstract

Disclosed is a liquid crystal display which comprise: a transparent insulating substrate; a plurality of source bus lines and a plurality of gate bus lines arranged in rows and columns at right angles to each other on a surface of the transparent insulating substrate; a plurality of thin film transistors formed on the surface of the transparent insulating substrate, each connected to the source bus lines and the gate bus lines in the vicinity of their intersection and each comprising source, drain and gate electrodes; a plurality of pixel electrodes comprising first pixel electrodes and second pixel electrodes formed in alternative array at different level layers of upper and lower layers on the surface of the transparent insulating substrate from each other, and each connected to the drain electrode of the thin film transistors, wherein the first pixel electrodes are formed in even columns of the lower level layer and comprise first extended portions overlapped with at least the source bus lines at both sides thereof in the row direction, wherein the second pixel electrodes are formed in odd columns of the upper level layer and comprise second extended portions overlapped with at least the data lines at both sides thereof in the row direction; a first insulating layer disposed between the source bus lines and the first pixel electrodes; and a second insulating layer disposed between the first and second pixel electrodes.

Claims

1. A liquid crystal display comprising with overlapped pixel electrodes;

a transparent insulating substrate;

a plurality of source bus lines and a plurality of gate bus lines arranged in rows and columns at right angle to each other on a surface of the transparent insulating substrate, wherein a pair of source bus lines and a pair of gate bus lines define a unit cell region;

a plurality of thin film transistors formed on a surface of the transparent insulating substrate, each connected to the source bus lines and the gate bus lines in a vicinity of their intersection and each comprising source, drain and gate electrodes;

a plurality of pixel electrodes comprising first pixel electrodes and second pixel electrodes formed in alternative array at different level layers of upper and lower layers on the surface of the transparent insulating substrate from each other, and each of the first and second pixel electrodes connected to the drain electrode of a corresponding one of the thin film transistors, wherein the first pixel electrodes are formed in even columns of the lower level layer and comprise first extended portions overlapped with at least the plurality of source bus lines at both sides thereof in the row direction, wherein the second pixel electrodes are formed in odd columns of the upper level layer and comprise second extended portions overlapped with at least the plurality of source lines at both sides thereof in the row direction;

a first insulating layer disposed between the source bus lines and the first extended portions of the first pixel electrodes; and

a second insulating layer disposed between the first extended portions of the first pixel electrode and the second extended portions of the second pixel electrodes.

2. The liquid crystal display as claimed in claim 1, wherein the first and second extended portions each is extended to both sided edge portions of two pixel electrodes adjacent thereto in the row direction.

3. The liquid crystal display as claimed in claim 1, wherein the first and second pixel electrodes each further comprises a third extended portion overlapped with a corresponding one of the gate bus lines.

4. The liquid crystal display as claimed in claim 3, wherein the third extended portion has a different overlapped area from each other in the odd and even columns.

5. The liquid crystal display as claimed in claim 3, wherein the third extended portion has the same overlapped area in the odd and even columns.

6. The liquid crystal display as claimed in claim 3, wherein the third extended portion is formed in either the even or odd columns.

7. The liquid crystal display as claimed in claim 6, wherein the third extended portion is formed in the odd columns.

8. The liquid crystal display as claimed in claim 2, wherein the first and second pixel electrodes further comprises a fourth extended portion overlapped with a previous one of the gate bus lines.

9. The liquid crystal display as claimed in claim 8, wherein the fourth extended portion has a different overlapped portion in the odd and even columns.

10. The liquid crystal display as claimed in claim 8, wherein the fourth extended portion has the same overlapped area in the odd and even columns.

11. The liquid crystal display as claimed in claim 8, wherein the fourth extended portion is formed in either the odd or even columns.

12. The liquid crystal display as claimed in claim 1, wherein the first insulating layer is extended to upper surfaces of the thin film transistors such that it protects the thin film transistors.

13. The liquid crystal display as claimed in claim 1, further comprising a passivation layer for protecting the thin film transistors.

14. The liquid crystal display as claimed in claim 13, wherein said passivation layer is formed of the same material as the first insulating layer.

15. The liquid crystal display as claimed in claim 1, wherein a first overlapped area between the source bus line and the first pixel electrode, a second overlapped area between the first and second pixel electrodes, dielectric constants of the first insulating layer and the second insulating layer are determined such that total capacitance for a pixel electrode is the same as that for another pixel electrode.

16. The liquid crystal display as claimed in claim 1, wherein a dielectric constant of the second insulating layer is in the range of 2 to 4.

17. The liquid crystal display as claimed in claim 16, wherein said second insulating layer is formed of resin insulator.

18. The liquid crystal display as claimed in claim 1, wherein a dielectric constant of the second insulating layer is larger than that of the first insulating layer.

19. A method for fabricating a liquid crystal display, comprising the steps of:

providing a transparent insulating substrate on which a plurality of source bus lines and a plurality of gate bus lines arranged in rows and columns at right angle to each other for defining a plurality of unit pixel region each bounded by a pair of source bus lines and a pair of gate bus lines, and a plurality of thin film transistors connected to the source bus lines and gate bus lines, respectively are formed, thereby forming a resultant structure;

forming a first insulating layer on the resultant structure including at least the thin film transistors and the source bus lines;

forming, at either odd or even columns, first pixel electrodes extended, to both unit cell regions adjacent thereto and beyond the source bus lines at both sides thereof, in the row direction;

forming a second insulating layer on the resultant substrate including the first pixel electrode and the first insulating layer; and

forming, at the remaining columns, second pixel electrodes extended, to both unit cell regions adjacent thereto and beyond the source bus lines at both sides thereof, in the row direction.

20. The method as claimed in claim 19, wherein the second insulating layer is made of resin having a dielectric constant of a range of 2 to 4.