Gate drive circuit having reduced size, display substrate having the same, and method of manufacturing the display substrate

• US 9,257,455 B2
• Filed: 11/03/2011
• Issued: 02/09/2016
• Est. Priority Date: 12/27/2010
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: Koo, Bon-Yong, Kim, Sung-Man, Lee, Jae-Hoon
• Primary Examiner(s): Park, Sanghyuk
• Application Number:
  US13/288,893
• Publication Number:
  US 20120161820A1
• Time in Patent Office: 1,559 Days
• Field of Search: 345 87-104, 345211-213
• US Class Current: 1/1
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers
• CPC Class Codes: H01L 27/1255 integrated with passive devices, e.g. auxiliary capacitors
• CPC Class Codes: H01L 27/1259 Multistep manufacturing methods
• CPC Class Codes: H01L 29/41733 for thin film transistors with insulated gate

Abstract

A gate drive circuit includes plural stages connected together one after each other. Each of the plural stages includes a circuit transistor, a capacitor part, a first connection part and a second connection part. The circuit transistor outputs the gate signal through a source electrode in response to a control signal applied through a gate electrode. The capacitor part includes a first electrode, a second electrode formed on the first electrode, and a third electrode formed on the second electrode. The first connection part electrically connects the gate electrode of the circuit transistor and the second electrode of the capacitor part. The second connection part electrically connects the source electrode of the circuit transistor and the first electrode of the capacitor part. Thus, an integrated size of a gate drive circuit may be decreased, and a reliability of a gate drive circuit may be enhanced.

Claims

1. A gate drive circuit in which plural stages are connected together one after each other, the plural stages configured to output a plurality of gate signals,

each of the plural stages comprising:

a circuit transistor configured to output the gate signal to an output terminal of the respective stage in response to a control signal applied through a gate electrode;

a capacitor part formed adjacent to the circuit transistor and having two capacitors connected to the gate electrode of the circuit transistor and to the output terminal, the capacitor part comprising a first electrode, a second electrode formed on the first electrode, and a third electrode formed on the second electrode, the first, second and third electrode of the capacitor part being different from the gate electrode and a source electrode of the circuit transistor;

a first connection part directly connecting the gate electrode of the circuit transistor and the second electrode of the capacitor part; and

a second connection part directly connecting an output electrode of the circuit transistor and the first electrode of the capacitor part;

wherein the third electrode is formed from a same layer as that of a pixel electrode.

2. The gate drive circuit of claim 1, wherein the gate signal outputted by the circuit transistor is outputted to the first electrode of the capacitor part through the second connection part.

3. The gate drive circuit of claim 1, further comprising:

a first insulation layer formed between the first electrode of the capacitor part and the second electrode of the capacitor part; and

a second insulation layer formed between the second electrode of the capacitor part and the third electrode of the capacitor part.

4. The gate drive circuit of claim 3, wherein the first connection part comprises:

a first bridge electrode electrically connecting the gate electrode and the second electrode through a first contact hole exposing the gate electrode of the circuit transistor and a second contact hole exposing the second electrode of the capacitor part.

5. The gate drive circuit of claim 3, wherein the second connection part comprises:

a second bridge electrode electrically connecting the output electrode of the circuit transistor and the first electrode through a third contact hole exposing the output electrode of the circuit transistor and a fourth contact hole exposing the first electrode of the capacitor part.

6. The gate drive circuit of claim 5, wherein the second bridge electrode is extended from the third electrode.

7. The gate drive circuit of claim 1, wherein the first electrode of the capacitor part and the gate electrode of the circuit transistor are formed from a same material.

8. The gate drive circuit of claim 1, wherein the second electrode of the capacitor part and the output electrode of the circuit transistor are formed from a same material.

9. A display substrate comprising:

a base substrate comprising a display area and a peripheral area surrounding the display area;

a pixel part formed on the display area, the pixel part comprising pixel transistors connected to gate lines and data lines and pixel electrodes connected to the pixel transistors; and

a gate drive circuit formed on the peripheral area, the gate drive circuit having plural stages connected together one after each other, the plural stages configured to output a plurality of gate signals to the gate lines, each of the stages of the gate drive circuit comprising;

a circuit transistor configured to output the gate signal to an output terminal of the respective stage in response to a control signal applied through a gate electrode;

a capacitor part formed adjacent to the circuit transistor and having two capacitors connected to the gate electrode of the circuit transistor and to the output terminal, the capacitor part comprising a first electrode, a second electrode formed on the first electrode, and a third electrode formed on the second electrode, the first, second and third electrode of the capacitor part being different from the gate electrode and a source electrode of the circuit transistor;

a first connection part directly connecting the gate electrode of the circuit transistor and the second electrode of the capacitor part; and

a second connection part directly connecting an output electrode of the circuit transistor and the first electrode of the capacitor part;

wherein the third electrode is formed from a same layer as that of a pixel electrode of the pixel part.

10. The display substrate of claim 9, wherein the gate signal outputted by the circuit transistor is outputted to the first electrode of the capacitor part through the second connection part.

11. The display substrate of claim 10, wherein the first electrode of the capacitor electrode part is extended from the gate line.

12. The display substrate of claim 9, wherein the gate drive circuit further comprises:

a first insulation layer formed between the first electrode of the capacitor part and the second electrode of the capacitor part; and

a second insulation layer formed between the second electrode of the capacitor part and the third electrode of the capacitor part.

13. The display substrate of claim 12, wherein the first connection part comprises:

a first bridge electrode electrically connecting the gate electrode and the second electrode through a first contact hole exposing the gate electrode of the circuit transistor and a second contact hole exposing the second electrode of the capacitor part.

14. The display substrate of claim 12, wherein the second connection part comprises:

a second bridge electrode electrically connecting the output electrode of the circuit transistor and the first electrode through a third contact hole exposing the output electrode of the circuit transistor and a fourth contact hole exposing the first electrode of the capacitor part.

15. The display substrate of claim 14, wherein the second bridge electrode is extended from the third electrode of the capacitor part.

16. The display substrate of claim 9, wherein the gate line, the first electrode of the capacitor part and the gate electrode of the circuit transistor are formed from a same material.

17. The display substrate of claim 9, wherein the data line, the second electrode of the capacitor part and the source electrode of the circuit transistor are formed from a same material.

18. The display substrate of claim 9, wherein the pixel electrode and the third electrode of the capacitor part are formed from a same material.

19. A method of manufacturing a display substrate, the method comprising:

forming a gate pattern on a base substrate, the gate pattern comprising a gate line and a gate electrode of a pixel transistor on a display area of the base substrate, and a first electrode of a capacitor part and a gate electrode of a circuit transistor on a peripheral area surrounding the display area;

forming a first insulation layer, a semiconductor pattern, an ohmic contact layer, and a source metal layer on the base substrate on which the gate pattern is formed;

patterning the source metal layer to form a data line on the display area, drain/source electrodes of the pixel transistor on the display area, a second electrode of the capacitor part on the peripheral area and positioned over the first electrode of the capacitor part, drain/source electrodes of the circuit transistor on the peripheral area, and an active pattern below the source pattern;

forming a second insulation layer on the base substrate on which the source pattern is formed; and

forming a pixel electrode, a first connection part, a second connection part and a third electrode of the capacitor part on the display area, the peripheral area, the peripheral area and the peripheral area, respectively, the third electrode of the capacitor part being positioned over the first and second electrodes of the capacitor part so that the second electrode of the capacitor part is positioned between the first and third electrodes of the capacitor part, the pixel electrode being electrically connected to the drain electrode of the pixel transistor, the first connection part directly connecting the gate electrode of the circuit transistor and the second electrode of the capacitor part, and the second connection part electrically connecting the source electrode of the circuit transistor and the first electrode of the capacitor part,

wherein the first, second and third electrodes of the capacitor part are different from the gate electrode and the source electrode of the circuit transistor.

20. The method of claim 19, wherein forming the first connection part and the second connection part comprises:

partially removing the first insulation layer and the second insulation layer to expose the drain electrode of the pixel transistor, the gate electrode and the source electrode of the circuit transistor, and the first electrode and the second electrode of the capacitor part;

forming an optically transparent and electrically conductive material on the second insulation layer; and

patterning the optically transparent and electrically conductive material to form the pixel electrode, the first connection part, the second connection part and the third electrode.