Active-type electroluminescent display

• US 6,911,960 B1
• Filed: 11/29/1999
• Issued: 06/28/2005
• Est. Priority Date: 11/30/1998
• Status: Expired due to Term

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Yokoyama, Ryoichi
• Primary Examiner(s): Wu, Xiao
• Assistant Examiner(s): ABDULSELAM, ABBAS I
• Application Number:
  US09/450,491
• Time in Patent Office: 2,038 Days
• Field of Search: 345/45, 345/80, 345/85, 345/87, 345/92, 345/76, 345/81, 313/505, 313/491, 313/506, 257/83, 257/84, 257/88, 257/103
• US Class Current: 345/76
• CPC Class Codes: G09G 2300/0809 Several active elements per pixel in active matrix panels
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 3/3225 using an active matrix
• CPC Class Codes: H10K 50/826 Multilayers, e.g. opaque multilayers
• CPC Class Codes: H10K 59/123 Connection of the pixel electrodes to the thin film transistors [TFT]
• CPC Class Codes: H10K 59/131 Interconnections, e.g. wiring lines or terminals
• CPC Class Codes: H10K 59/80523 Multilayers, e.g. opaque multilayers

Abstract

In an active-type electroluminescent (EL) display, a conductor interconnecting a cathode (55) of an EL panel (30, 40) and a connection terminal of a signal input substrate (35) has a multilayer structure formed of a cathode material and a conductive material used in a thin-film transistor forming step. The conductor may be formed of a conductive material used in a thin film transistor forming step. A metal material for a gate electrode or drain electrode is preferably used as the conductive material. The connection conductor structure can reduce the electrical resistance of the connection conductor, thus preventing a decrease in display intensity of an EL display.

Claims

1. An active-type light emitting display comprising:

a light emission panel including light emission elements each having a first electrode, a second electrode, and an emissive portion, and thin film transistors for respectively driving said light emission elements;

said light emission elements and at least one of said thin film transistor are formed on or above a same substrate;

said first electrode is electrically connected to at least one of said thin film transistors and is formed over an insulating layer, which is formed covering said at least one of said thin film transistors;

said second electrode is formed in a pattern that is common for a plurality of pixels, above said first electrode;

said thin film transistor includes a first conductive material that is formed between said substrate and said first electrode, said first conductive material is formed below said second electrode;

a connection conductor for connecting said second electrode and a signal supply portion, said signal supply portion supplying a signal to said second electrode for controlling said second electrode separately from said first electrode; and

said connection conductor having a section between said second electrode and said signal supply portion, at least a part of said section being a multilayer structure formed of a second electrode material used for said second electrode and a second conductive material, said first conductive material is the same material as said second conductive material, said multilayer structure having a resistance lower than a resistance of a single layer of said second electrode material.

2. The active-type light emission display defined in claim 1, wherein said conductive material used for said thin film transistors and said connection conductor comprises a material used for a gate electrode, a drain electrode, or a source electrode of each of said thin film transistors, or comprises an arbitrary combination of materials used for said gate electrode, said drain electrode and said source electrode thereof.

3. The active-type light emission display defined in claim 1, wherein said conductive material used for said thin film transistors and said connection conductor comprises a metal material used for a gate electrode or drain electrode of each of said thin film transistors.

4. The active-type light emission display defined in claim 1, wherein said second electrode comprises a common electrode spreading over substantially the whole of said panel.

5. The active-type light emission display defined in claim 1, wherein said light emission element comprises an electroluminescent element in which an emissive layer is interposed between said first electrode and said second electrode.

6. The active-type light emission display defined in claim 5, wherein said emissive layer comprises an organic compound having a luminous function.

7. The active-type light emission display defined in claim 1, wherein an active layer of each of said thin film transistors comprises a polycrystalline silicon layer.

8. The active-type light emissuion display defined in claim 1, wherein said signal supply portion comprises an external device connected to said light emission panel via terminals.

9. An active-type electroluminescent display comprising:

a light emission panel including light emission elements each having a first electrode, a second electrode, and a luminous portion, and thin film transistors for respectively driving said light emission elements;

said light emission elements and at least one of said thin film transistor are formed on or above a same substrate;

said first electrode is electrically connected to at least one of said thin film transistors and is formed over an insulating layer, which is formed covering said at least one of said thin film transistors;

said second electrode is formed in a pattern that is common for a plurality of pixels, above said first electrode;

said thin film transistor includes a first conductive material that is formed between said substrate and said first electrode, said first conductive material is formed below said second electrode;

a connection conductor for connecting said second electrode and a signal supply portion, said signal supply portion supplying a signal to said second electrode for controlling said second electrode separately from said first electrode; and

said connection conductor having a section between said second electrode and said signal supply portion, at least a part of said section being formed of a second conductive material, said first conductive material is the same material as said second conductive material, said part having a resistance lower than a resistance of a single layer of a material used for said second electrode.

10. The active-type electroluminescent display defined in claim 9, wherein said conductive material used for said thin film transistors and said connection conductor comprises a material used for a gate electrode, a drain electrode, or a source electrode of each of said thin film transistors, or comprises an arbitrary combination of materials used for said gate electrode, said drain electrode and said source electrode thereof.

11. The active-type electroluminescent display defined in claim 9, wherein said conductive material used for said thin film transistors and said connection conductor comprises a metal material used for a gate electrode or drain electrode of each of said thin film transistors.

12. The active-type electroluminescent display defined in claim 9, wherein said second electrode comprises a common electrode spreading over substantially the whole of said panel.

13. The active-type electroluminescent display defined in claim 9, wherein said light emission element comprises an electroluminiscent element in which an emissive layer is interposed between said first electrode and said second electrode.

14. The active-type electroluminiscent display defined in claim 13, wherein said emissive layer comprises an organic compound having a luminous function.

15. The active-type electroluminiscent display defined in claim 9, wherein an active layer of each of said thin film transistors comprises a polycrystalline silicon layer.

16. The active-type electroluminscent display defined in claim 9, wherein said signal supply portion comprises an external device connected to said light emission panel via terminals.

17. An active-type light emitting display comprising:

a light emission panel including light emission element each having a first electrode, a second electrode, and an emissive portion, and thin film transistors for respectively driving said light emission elements;

said light emission elements and at least one of said thin film transistor are formed on or above a same substrate;

said first electrode is electrically connected to at least one of said thin film transistors and is formed over an insulating layer, which is formed covering said at least one of said thin film transistors;

said second electrode is formed in a pattern that is common for a plurality of pixels, above said first electrode; and

said thin film transistor includes a first conductive material that is formed between said substrate and said first electrode, said first conductive material is formed below said second electrode;

a connection conductor for connecting said second electrode and a signal supply portion, said signal supply portion supplying a signal to said second electrode for controlling said second electrode separately from said first electrode;

said connection conductor having a section between said second electrode and said signal supply portion, at least a part of said section being a multilayer structure formed of a second electrode material used for said second electrode and a second conductive material, said first conductive material is the same material as said second conductive material, said multilayer structure having a resistance lower than a resistance of a single layer of said second electrode material.

18. An active-type electroluminescent display comprising:

a light emission panel including light emission elements each having a first electrode, a second electrode, and a luminous portion, and thin film transistors for respectively driving said light emission elements;

said light emission elements and at least one of said thin film transistor are formed on or above a same substrate;

said first electrode is electrically connected to at least one of said thin film transistors and is formed over an insulating layer, which is formed covering said at least one of said thin film transistors;

said second electrode is formed in a pattern that is common for a plurality of pixels above said first electrode;

said thin film transistor includes a first conductive material that is formed between said substrate and said first electrode, said first conductive material is formed below said second electrode;

a connection conductor for connecting said second electrode and a signal supply portion, said signal supply portion supplying a signal to said second electrode for controlling said second electrode separately from said first electrode; and

said connection conductor having a section between said second electrode and said signal supply portion, at least a part of said section being formed of a second conductive material, said first conductive material is the same material as said second conductive material, said part having a resistance lower than a resistance of a single layer of a material used for said second electrode.