ACTIVE MATRIX SUBSTRATE AND PRODUCING METHOD OF THE SAME

• US 20010045996A1
• Filed: 06/26/1997
• Published: 11/29/2001
• Est. Priority Date: 07/02/1996
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: OKAMOTO, MASAYA, YAMAKAWA, SHINYA, KATAYAMA, MIKIO, KAWAI, KATSUHIRO, SHIMADA, TAKAYUKI
• Granted Patent: US 6,411,348 B2
• Time in Patent Office: Days
• US Class Current: 349/40
• CPC Class Codes: G02F 1/136204 Arrangements to prevent high voltage or static electricity failures

Abstract

An active matrix is furnished with an insulating substrate; a plurality of scanning lines and signal lines provided on the insulating substrate in a matrix pattern; pixel electrodes provided in areas enclosed by the scanning lines and signal lines, respectively; switching elements electrically connected to the scanning lines, signal lines, and pixel electrodes, respectively; a resistance control element for electrically connecting two lines selected arbitrary from the scanning lines and signal lines while controlling its own resistance value in response to a voltage applied thereto. According to the above arrangement, it has become possible to increase a margin of the active matrix substrate for the static electricity and improve the production yield without increasing the number of the producing steps.

Claims

1. An active matrix substrate comprising:

an insulating substrate;

a plurality of scanning lines and signal lines provided on said insulating substrate in a matrix pattern;

pixel electrodes, each of which being provided to areas enclosed by said scanning lines an signal lines, respectively;

switching elements electrically connected to said scanning lines, signal lines, and pixel electrodes, respectively; and

a resistance control element for electrically connecting at least two lines selected arbitrary from said scanning lines and signal lines, said resistance control element being capable of varying a resistance value thereof under control in response to a voltage applied thereto.

2. The active matrix substrate of

claim 1

, wherein said at least two lines connected through said resistance control element are selected from said scanning lines.

3. The active matrix substrate of

claim 1

, wherein said at least two lines connected through said resistance control element are selected from said signal lines.

4. The active matrix substrate of

claim 1

, wherein said resistance control element is composed of a pair of 2-terminal elements connected to a single line in parallel, through which signals flow in opposite directions.

5. The active matrix substrate of

claim 4

, wherein said signal electrodes and pixel electrodes are made of a same conductive film.

6. The active matrix substrate of

claim 4

, wherein said each 2-terminal element is composed of a thin film transistor whose scanning electrode and signal electrode are connected to each other electrically.

7. The active matrix substrate of

claim 6

, wherein said thin film transistor is a channel-etch type transistor whose channel portion is made through etching.

8. A method of producing an active matrix substrate comprising an insulating substrate, a plurality of scanning lines and signal lines provided on said insulating substrate in a matrix pattern, pixel electrodes, each of which being provided to areas enclosed by said scanning lines an signal lines, respectively, and switching elements electrically connected to said scanning lines, signal lines, and pixel electrodes, respectively,

wherein a resistance control element is formed concurrently with said switching elements to electrically connect at least two lines selected arbitrary from said scanning lines and signal lines, and to vary a resistance value thereof under control in response to a voltage applied thereto.

9. A producing method of an active matrix substrate comprising the steps of:

forming a first conductive film used as a scanning line material on an insulating substrate;

forming scanning lines, scanning electrodes, scanning electrodes of thin film transistors used as 2-terminal elements by patterning said first conductive film into a predetermined shape;

forming a first insulating layer, a first semiconductor layer, and a second insulating layer sequentially over an area including said scanning lines, scanning electrodes, and the scanning electrodes of said thin film transistors used as the 2-terminal elements;

forming a channel protecting layer by patterning said second insulating film substantially in a same shape as said scanning electrodes and the scanning electrodes of said thin film transistors used as the 2-terminal elements;

forming a second semiconductor layer which will be made into a contact layer over an area including said scanning lines, scanning electrodes, and the scanning electrodes of said thin film transistors used as the 2-terminal elements;

forming channel portions of said thin film transistors and said contact layer by patterning said first and second semiconductor layers into a predetermined shape, respectively;

forming a second conductive film which will be made into signal lines, signal electrodes, drain electrodes, signal electrodes, and drain electrodes of said thin film transistors used as the 2-terminal elements over an area including said contact layer;

forming said signal lines, signal electrodes, drain electrodes, and the signal electrodes and drain electrodes of said thin film transistors used as the 2-terminal elements by patterning said second conductive film into a predetermined shape;

forming a third conductive film which will be made into pixel electrodes; and

forming said pixel electrodes by patterning said third conductive film into a predetermined shape.

10. The producing method of an active matrix substrate of

claim 9

further comprising the step of anodizing a surface of said first conductive film before said first insulating film is formed.

11. The producing method of an active matrix substrate of

claim 9

, wherein said first conductive film is made of tantalum.

12. The producing method of an active matrix substrate of

claim 9

, wherein said first insulating film is made of titanium nitride.

13. The producing method of an active matrix substrate of

claim 9

, wherein said second conductive film is made of titanium.

14. The producing method of an active matrix substrate of

claim 9

, wherein said second insulating film is made of titanium nitride.

15. The producing method of an active matrix substrate of

claim 9

, wherein said pixel electrodes are made of a transparent conductive film.

16. A producing method of an active matrix substrate comprising the steps of:

forming a first conductive film which will be used as a scanning line material on an insulating substrate;

forming scanning lines, scanning electrodes, scanning electrodes of thin film transistors used as 2-terminal elements by patterning said first conductive film into a predetermined shape;

forming an insulating layer and a first semiconductor layer sequentially over an area including said scanning lines, scanning electrodes, and the scanning electrodes of said thin film transistors used as the 2-terminal elements;

forming a second semiconductor layer which will be made into a contact layer over an area including said scanning lines, scanning electrodes, and the scanning electrodes of said thin film transistors used as the 2-terminal elements;

forming channel portions of said thin film transistors and said contact layer by patterning said first and second semiconductor layers into a predetermined shape, respectively;

forming a second conductive film which will be made into signal lines, signal electrodes, drain electrodes, and signal electrodes and drain electrodes of said thin film transistors used as the 2-terminal elements over an area including said contact layer;

forming said signal lines, signal electrodes, drain electrodes, and the signal electrodes and drain electrodes of said thin film transistors used as the 2-terminal elements by patterning said second conductive film into a predetermined shape;

forming a third conductive film which will be made into pixel electrodes; and

forming said pixel electrodes by patterning said third conductive film into a predetermined shape.

17. A producing method of an active matrix substrate comprising the steps of:

forming a first conductive film which is used as a scanning line material on an insulating substrate;

forming scanning lines, scanning electrodes, and scanning electrodes of thin film transistors used as 2-terminal elements by patterning said first conductive layer into a predetermined shape;

forming an insulating layer and a first semiconductor layer sequentially over an area including said scanning lines, scanning electrodes, and the scanning electrodes of said thin film transistors used as the 2-terminal elements;

forming, after forming a second semiconductor layer which will be made into a contact layer over said scanning lines, scanning electrodes, and an area above the scanning electrodes of said thin film transistors used as the 2-terminal elements, a second conductive film as a material of signal lines, signal electrodes, drain electrodes, and signal electrodes and drain electrodes of said thin film transistors used as 2-terminal elements;

forming said signal lines, signal electrodes, drain electrodes, and the signal electrodes and drain electrodes of said thin film transistors used as the 2-terminal elements by patterning said second conductive film into a predetermined shape;

forming channel portions of said thin film transistors and said contact layer by etching said first and second semiconductor layers using said signal electrodes, drain electrodes, and the signal electrodes and drain electrodes of said thin film transistors used as the 2-terminal elements as a mask;

forming a third conductive film which will be made into pixel electrodes; and

forming said pixel electrodes by patterning said third conductive film into a predetermined shape.