Actively driven organic EL device and manufacturing method thereof

• US 6,538,374 B2
• Filed: 02/16/2001
• Issued: 03/25/2003
• Est. Priority Date: 02/16/2000
• Status: Expired due to Term

• Current Assignee: Idemitsu Kosan Company Limited
• Original Assignee: Idemitsu Kosan Company Limited
• Inventors: Hosokawa, Chishio
• Primary Examiner(s): O'Shea, Sandra
• Assistant Examiner(s): Lee, Guiyoung
• Application Number:
  US09/784,030
• Publication Number:
  US 20020011783A1
• Time in Patent Office: 767 Days
• Field of Search: 313/504, 313/506, 313/503, 313/509, 315/169.3, 345/76, 345/92, 345/45, 445/24
• US Class Current: 313/504
• CPC Class Codes: H05B 33/12 Light sources with substantially two-dimensional radiating surfaces
• CPC Class Codes: H10K 2102/3026 Top emission
• CPC Class Codes: H10K 50/81 Anodes
• CPC Class Codes: H10K 50/814 combined with auxiliary electrodes, e.g. ITO layer combined with metal lines
• CPC Class Codes: H10K 50/824 combined with auxiliary electrodes
• CPC Class Codes: H10K 50/828 Transparent cathodes, e.g. comprising thin metal layers
• CPC Class Codes: H10K 50/86 Arrangements for improving contrast, e.g. preventing reflection of ambient light
• CPC Class Codes: H10K 50/865 comprising light absorbing layers, e.g. light-blocking layers
• CPC Class Codes: H10K 59/12 Active-matrix OLED [AMOLED] displays
• CPC Class Codes: H10K 59/122 Pixel-defining structures or layers, e.g. banks
• CPC Class Codes: H10K 59/131 Interconnections, e.g. wiring lines or terminals
• CPC Class Codes: H10K 59/1315 comprising structures specially adapted for lowering the resistance
• CPC Class Codes: H10K 59/80516 combined with auxiliary electrodes, e.g. ITO layer combined with metal lines
• CPC Class Codes: H10K 59/80522 combined with auxiliary electrodes
• CPC Class Codes: H10K 59/80524 Transparent cathodes, e.g. comprising thin metal layers
• CPC Class Codes: H10K 59/8792 comprising light absorbing layers, e.g. black layers

Abstract

The present invention is a active-driving organic EL light emission device comprising an organic EL element comprising an organic luminous medium between an upper electrode and a lower electrode, and a thin film transistor for driving this organic EL element, wherein light emitted from the organic EL element is taken out from the side of the upper electrode, and the upper electrode comprises a main electrode formed of transparent conductive material, and an auxiliary electrode formed of a low-resistance material. According to the active-driving organic EL light emission device of this structure, the numerical aperture can be made large. Additionally, the sheet resistivity of the upper electrode can be made low even if luminescence is taken out from the side of the upper electrode. Thus, it is possible to provide an active-driving organic EL light emission device making it possible to display images having a high brightness and a homogenous brightness; and a method for manufacturing the same.

Claims

1. An active-driving organic EL light emission device comprising:

an organic EL element comprising an organic luminous medium between an upper electrode and a lower electrode; and

a thin film transistor for driving the organic EL element;

wherein light emitted from the organic EL element is taken out from a side of the upper electrode; and

the upper electrode comprises a main electrode formed of a transparent conductive material, and an auxiliary electrode formed of a low-resistance material.

2. The device according to claim 1, further comprising an electric switch comprising the thin film transistor and a transistor for selecting a pixel, and

a signal electrode line and a scanning electrode line for driving the electric switch.

3. The device according to claim 1, wherein the transparent conductive material is at least one material selected from the group consisting of conductive oxides, light-transmissible metal films, non-degenerate semiconductors, organic conductors, and semiconductive carbon compounds.

4. The device according to claim 3, wherein the organic conductor is at least one material selected from the group consisting of conductive conjugated polymers, oxidizing agent-added polymers, reducing agent-added polymers, oxidizing agent-added low-molecules, and reducing agent-added low-molecules.

5. The device according to claim 3, wherein the non-degeneracy semiconductors are at least one material selected from the group consisting of oxides, nitrides, and calchogenide compounds.

6. The device according to claim 3, wherein the carbon compounds comprise at least one material selected from the group consisting of amorphous carbon, graphite, and diamond-like carbon.

7. The device according to claim 1, wherein a plurality of auxiliary electrodes are regularly placed in a plane.

8. The device according to claim 1, wherein a sectional shape of the auxiliary electrode is an overhang form.

9. The device according to claim 1, wherein the auxiliary electrode comprises a lower auxiliary electrode and an upper auxiliary electrode.

10. The device according to claim 9, wherein the lower auxiliary electrode and the upper auxiliary electrode comprise constituent materials having different etching rates.

11. The device according to claim 9, wherein the lower auxiliary electrode and the upper auxiliary electrode of the auxiliary electrode, or one thereof is electrically connected to the main electrode.

12. The device according to claim 1, wherein the auxiliary electrode is formed on an interlayer dielectric constituting the organic EL element.

13. The device according to claim 1, wherein the auxiliary electrode is formed on an electrically insulating film for insulating the lower electrode electrically.

14. The device according to claim 1, wherein the auxiliary electrode is formed on an electrically insulating film for insulating the thin film transistor electrically.

15. The device according to claim 1, wherein an active layer of the thin film transistor comprises polysilicon.

16. The device according to claim 1, wherein an interlayer dielectric is formed on the thin film transistor, the lower electorode of the organic EL element is deposited on the interlayer dielectric, and the thin film transistor and the lower electrode are electrically connected to each other through a via hole made in the interlayer dielectric.

17. The device according to claim 1, wherein charges are injected from the auxiliary electrode to the main electrode and transported in parallel to a main surface of a substrate, and subsequently the charges are injected to the organic luminous medium.

18. The device according to claim 1, wherein the sheet resistivity of the main electrode is set to a value within the range of 1K to 10 MΩ

/□

.

19. The device according to claim 1, wherein the sheet resistivity of the auxiliary electrode is set to a value within the range of 0.01 to 10 Ω

/□

.

20. The device according to claim 1, further comprising a fluorescent film and a color filter for color-converting the taken-out light, or one thereof is arranged on the side of the upper electrode.

21. The device according to claim 1, wherein a black matrix is formed on a part of the color filter or the fluorescent film, and the black matrix and the auxiliary electrode overlap with each other in a vertical direction.

22. The device according to claim 1, wherein the auxiliary electrode is formed on the main electrode, and an area of the auxiliary electrode is smaller than an area of the main electrode.

23. The device according to claim 1, wherein the auxiliary electrode is embedded in a sealing member surrounding a periphery thereof.

24. The device according to claim 1, wherein the auxiliary electrode is closely arranged between the sealing member and the main electrode.

25. A method for manufacturing an active-driving organic EL light emission device comprising an organic EL element having an organic luminous medium between an upper electrode and a lower electrode, and a thin film transistor for driving the organic EL element, the method comprising the steps of:

forming the organic EL element; and

forming the thin film transistor,

wherein during the step of forming the organic EL element, the lower electrode and the organic luminous medium are formed and subsequently a main electrode is formed from a transparent conductive material and the upper electrode is formed by forming an auxiliary electrode from a low-resistance material.