Organic electroluminescent device and its manufacturing process

• US 6,396,208 B1
• Filed: 01/27/1999
• Issued: 05/28/2002
• Est. Priority Date: 01/27/1998
• Status: Expired due to Term

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: NEC Corporation
• Inventors: Ishikawa, Hitoshi, Toguchi, Satoru, Oda, Atushi
• Primary Examiner(s): Patel, Vip
• Assistant Examiner(s): QUARTERMAN, KEVIN J
• Application Number:
  US09/238,064
• Time in Patent Office: 1,217 Days
• Field of Search: 313/504,506,509,503,498
• US Class Current: 313/504
• CPC Class Codes: H10K 50/805 Electrodes
• CPC Class Codes: H10K 50/85 Arrangements for extracting light from the devices
• CPC Class Codes: H10K 59/805 Electrodes
• CPC Class Codes: H10K 59/875 Arrangements for extracting light from the devices

Abstract

An organic electroluminescent device in which the electrode in the light-emitting side has small protrusions to allow the counter electrode to have a concave shape so as to utilize reflection by the concave and inclined mirror faces of the counter electrode to improve light-collection efficiency.

Claims

1. An organic electro-luminescent device comprising:

a light-transparent substrate;

a first electrode adjacent the light-transparent substrate;

a second electrode spaced apart from the first electrode;

one or more organic layers including a luminescent layer located intermediate the first and second electrodes; and

a plurality of small protrusions formed on the first electrode,

the second electrode having a concave surface facing the organic layers including the luminescent layer and arranged as a light-reflective surface, and

wherein a light emitted in the luminescent layer comes out from the light-transparent substrate.

2. An organic electroluminescent device as claimed in claim 1, where the small protrusions have cylindrical shape.

3. An organic electroluminescent device as claimed in claim 1, where the minimum width of the small protrusions is 0.03 μ

m to 2 μ

m inclusive.

4. An organic electroluminescent device as claimed in claim 1, where the ratio of the total area of the bottom faces of the small protrusions to the area of the electrode having the protrusions is 5% to 50% inclusive.

5. An organic electroluminescent device as claimed in claim 1, where the minimum width of the small protrusions is 0.1 to 5 folds inclusive to the thickness of the organic film.

6. An organic electroluminescent device as claimed in claim 1, where the small protrusions are composed of a conductive material opaque to visible light.

7. An organic electroluminescent device as claimed in claim 1, where the first electrode having the small protrusions is composed of a conductive material transparent to visible light.

8. An organic electroluminescent device as claimed in claim 1, comprising, between the first electrode having small protrusions and said one or more than one organic layers including a luminescent layer, an insulating layer transparent to visible light, through which the small protrusions stuck out.

9. An organic electro-luminescent device having one or more than one organic layers including a luminescent layer between an anode and a cathode,

where either the anode or the cathode has an inclined face and the electrode having inclined faces is adapted to act as a light-reflective surface;

a plurality of holes are formed on the counter electrode to the electrode having inclined faces and the luminescent layer extends into the holes; and

the counter electrode with the holes are formed on a light-transparent substrate, from which a light emitted in the luminescent layer comes out.

10. An organic electroluminescent device as claimed in claim 9, where the holes has a stripe shape.

11. An organic electroluminescent device as claimed in claim 9, where the holes has a comb-line shape.

12. An organic electroluminescent device as claimed in claim 9, where the holes are formed leaving a plurality of island electrodes.

13. An organic electroluminescent device as claimed in claim 9, where the ratio of the total area of the holes to the area of the electrode having the holes is 10% to 85% inclusive.

14. An organic electroluminescent device as claimed in claim 9, where the diameter or the minimum width of the holes is 0.1 μ

m to 2 μ

m inclusive.

15. An organic electroluminescent device as claimed in claim 9, where the diameter or the minimum width of the holes is 0.5 to 10 folds inclusive.

16. An organic electroluminescent device as claimed in claim 9, where the thickness of the electrode having the holes is 0.3 to 5 folds inclusive to the thickness of the organic film.

17. An organic electroluminescent device as claimed in claim 9, where the plurality of holes are regularly aligned on a plane.

18. An organic electroluminescent device as claimed in claim 17, where the electrode having the holes consists of a plurality of base units, in which holes are formed in a given pattern, and a hole pattern in one base unit can be rotated by 90°

to be substantially identical to that in an adjacent base unit.