DISPLAY DEVICE

• US 20080316410A1
• Filed: 06/04/2008
• Published: 12/25/2008
• Est. Priority Date: 06/08/2007
• Status: Abandoned Application

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: TAKAHASHI, Erika, FUJII, Gen
• Application Number:
  US12/133,160
• Publication Number:
  US 20080316410A1
• Time in Patent Office: Days
• US Class Current: 349/139
• CPC Class Codes: C09K 19/582 Electrically active dopants, e.g. charge transfer agents
• CPC Class Codes: G02F 1/13439 characterised by their electrical, optical, physical properties; materials therefor; method of making
• CPC Class Codes: G02F 2202/022 polymeric
• CPC Class Codes: G02F 2202/16 conductive
• CPC Class Codes: H10K 50/81 Anodes
• CPC Class Codes: H10K 50/82 Cathodes
• CPC Class Codes: H10K 59/8051 Anodes
• CPC Class Codes: H10K 59/8052 Cathodes
• CPC Class Codes: H10K 71/311 Purifying organic semiconductor materials
• CPC Class Codes: H10K 71/60 Forming conductive regions or layers, e.g. electrodes

Abstract

To provide display devices with improved image quality and reliability or display devices with a large screen at low cost with high productivity, an electrode layer containing a conductive polymer is used as an electrode layer for a display element, and the concentration of ionic impurities contained in the electrode layer containing a conductive polymer is reduced (preferably to 100 ppm or less). Ionic impurities are ionized, and easily become mobile ions, and they deteriorate a liquid crystal layer or an electroluminescent layer, which is used for a display element. Therefore, an electrode layer containing a conductive polymer, in which such ionic impurities are reduced is provided; thus, reliability of the display device can be improved.

Claims

1. A display device comprising a display element having a pair of electrode layers,

wherein at least one of the pair of electrode layers contains a conductive polymer, and

concentration of ionic impurity in the at least one of the pair of electrode layers containing a conductive polymer is 100 ppm or less.

2. A display device according to claim 1,

wherein the display element has a liquid crystal layer, and

the pair of electrode layers and the liquid crystal layer are stacked with insulating layers serving as alignment films therebetween.

3. A display device according to claim 1,

wherein the display element has an electroluminescent layer, and

the pair of electrode layers and the electroluminescent layer are in contact with each other.

4. A display device according to claim 1,

wherein an anion of the ionic impurity is an ion of an element having an ionization energy of 6 eV or less.

5. A display device according to claim 1,

wherein an anion of the ionic impurity is an ion of one of an alkali metal and an alkaline earth metal.

6. A display device according to claim 1,

wherein a cation of the ionic impurity is included in an inorganic acid.

7. A display device according to claim 1,

wherein the conductive polymer is any one of polythiophene, polyaniline, polypyrrole, and a derivative thereof.

8. A display device according to claim 1,

wherein at least one of the pair of electrode layers includes an organic resin.

9. A display device according to claim 1,

wherein at least one of the pair of electrode layers has one of an organic acid, an organic cyano compound and a mixture thereof as a dopant.

10. A display device comprising a display element having a pair of electrode layers,

wherein the pair of electrode layers each contain a conductive polymer, and

concentration of ionic impurity in the pair of electrode layers each containing a conductive polymer is 100 ppm or less.

11. A display device according to claim 10,

wherein the display element has a liquid crystal layer, and

the pair of electrode layers and the liquid crystal layer are stacked with insulating layers serving as alignment films therebetween.

12. A display device according to claim 10,

wherein the display element has an electroluminescent layer, and

the pair of electrode layers and the electroluminescent layer are in contact with each other.

13. A display device according to claim 10,

wherein an anion of the ionic impurity is an ion of an element having an ionization energy of 6 eV or less.

14. A display device according to claim 10,

wherein an anion of the ionic impurity is an ion of one of an alkali metal and an alkaline earth metal.

15. A display device according to claim 10,

wherein a cation of the ionic impurity is included in an inorganic acid.

16. A display device according to claim 10,

wherein the conductive polymer is any one of polythiophene, polyaniline, polypyrrole, and a derivative thereof.

17. A display device according to claim 10,

wherein at least one of the pair of electrode layers includes an organic resin.

18. A display device according to claim 10,

wherein at least one of the pair of electrode layers has one of an organic acid, an organic cyano compound and a mixture thereof as a dopant.

19. A display device comprising:

a first electrode provided over a substrate;

an electroluminescent layer provided over the first electrode; and

a second electrode provided over the electroluminescent layer,

wherein the first electrode and the second electrode each contain a conductive polymer, and

concentration of ionic impurity in the first electrode and the second electrode each containing a conductive polymer is 100 ppm or less.

20. A display device according to claim 19,

wherein an anion of the ionic impurity is an ion of an element having an ionization energy of 6 eV or less.

21. A display device according to claim 19,

wherein an anion of the ionic impurity is an ion of one of an alkali metal and an alkaline earth metal.

22. A display device according to claim 19,

wherein a cation of the ionic impurity is included in an inorganic acid.

23. A display device according to claim 19,

wherein the conductive polymer is any one of polythiophene, polyaniline, polypyrrole, and a derivative thereof.

24. A display device according to claim 19,

wherein at least one of the first electrode and the second electrode includes an organic resin.

25. A display device according to claim 19,

wherein at least one of the first electrode and the second electrode has one of an organic acid, an organic cyano compound and a mixture thereof as a dopant.