Organic electroluminescent device and manufacturing method therefor

• US 20050023968A1
• Filed: 07/30/2004
• Published: 02/03/2005
• Est. Priority Date: 03/21/2000
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Morii, Katsuyuki
• Granted Patent: US 7,138,762 B2
• Time in Patent Office: Days
• US Class Current: 313/504
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: H10K 50/826 Multilayers, e.g. opaque multilayers
• CPC Class Codes: H10K 50/8426 Peripheral sealing arrangements, e.g. adhesives, sealants
• CPC Class Codes: H10K 50/844 Encapsulations

Abstract

An organic electroluminescent device includes an anode, a light-emitting layer, and a cathode, which has a structure formed by sequentially laminating, from the light-emitting layer side, a first cathode formed of a material having a work function of 3.0 eV or less, and a second cathode, formed of a material having a work function higher than that of the first cathode, so that the total thickness of the first and the second cathodes is 100 angstroms or less. These elements are stacked on a substrate, and light is emitted to an exterior of the device via at least the cathode.

Claims

1. An organic electroluminescent device comprising:

a substrate;

an anode;

a light-emitting layer formed of an organic material;

a cathode including a first cathode formed of a material having a work function of 3.0 eV or less and a second cathode formed of a material having a work function higher than the work function of the first cathode, the first and second cathodes being sequentially stacked in this order from the light-emitting layer, and light being emitted to the outside via at least the cathode; and

a sealing layer formed on the cathode, the sealing layer being formed of a light transmissive material including LiF.

2. The organic electroluminescent device according to claim 1, a thickness of the sealing layer being more than 300 angstroms and less than 500 angstroms.

3. The organic electroluminescent device according to claim 1, a total thickness of the first and the second cathodes being 100 angstroms or less.

4. The organic electroluminescent device according to claim 1, the first cathode including Ca or Au.

5. The organic electroluminescent device according to claim 1, the thickness y (angstrom) of the first cathode being such that 50≦

y≦

80.

6. The organic electroluminescent device according to claim 1, the thickness y (angstrom) of the first cathode being such that 55≦

y≦

65.

7. The organic electroluminescent device according to claim 1, the second cathode including Al.

8. The organic electroluminescent device according to claim 1, the thickness z (angstrom) of the second cathode being such that 10≦

z≦

20.

9. The organic electroluminescent device according to claim 1, the organic material forming the light-emitting layer being a polymeric material.

10. A method for manufacturing an organic electroluminescent device, comprising:

forming an anode on a substrate;

forming a light-emitting layer formed of an organic material above the anode;

forming a cathode above the light-emitting layer by laminating a first cathode formed of a material having a work function of 3.0 eV or less and a second cathode formed of a material having a work function higher than that of the first cathode in this order; and

forming a sealing layer on the cathode, the sealing layer being formed of a light transmissive material including LiF.

11. The method for manufacturing an organic electroluminescent device according to claim 10, wherein:

the forming of the cathode above the light-emitting layer is performed using a vacuum deposition method, and

the forming of the sealing layer on the cathode is performed using a vacuum deposition method.

12. The method for manufacturing an organic electroluminescent device according to claim 11,

wherein the forming of the cathode and the sealing layer is performed using vacuum deposition method without being exposed in the air.