Organic electroluminescent device and display

• US 20060220538A1
• Filed: 04/22/2004
• Published: 10/05/2006
• Est. Priority Date: 04/24/2003
• Status: Active Grant

• Current Assignee: Idemitsu Kosan Company Limited
• Original Assignee: Idemitsu Kosan Company Limited
• Inventors: Kuma, Hitoshi
• Granted Patent: US 7,358,661 B2
• Time in Patent Office: Days
• US Class Current: 313/506
• CPC Class Codes: H10K 50/19 Tandem OLEDs
• CPC Class Codes: H10K 50/852 comprising a resonant cavity structure, e.g. Bragg reflector pair

Abstract

An organic EL device and a display with excellent viewing-angle properties and high efficiency are provided. An organic electroluminescent device (1) comprising: a transparent electrode (12), a counter electrode (14) arranged opposite to the transparent electrode (12), one or more intermediate conductive layers (30, 32 and 34) and one or more organic emitting layers (20, 22, 24 and 26) arranged between the transparent electrode (12) and the counter electrode (14), wherein the difference between n_a and n_b is 0.2 or less when n_a is the refractive index of the intermediate conductive layer (30) and n_b is the refractive index of the organic emitting layer (20).

Claims

1. An organic electroluminescent device comprising:

a transparent electrode,

a counter electrode arranged opposite to the transparent electrode,

one or more intermediate conductive layers and one or more organic emitting layers arranged between the transparent electrode and the counter electrode,

wherein the difference between n_a and n_b is 0.2 or less when n_a is the refractive index of an intermediate conductive layer and n_b is the refractive index of an organic emitting layer.

3. The organic electroluminescent device according to claim 1, wherein the intermediate conductive layer, the refractive index of which is n_a, is a laminate comprising a layer having a higher refractive index than n_b and/or n_c and a layer having a lower refractive index than n_b and/or n_c.

4. The organic electroluminescent device according to claim 1, wherein the intermediate conductive layer, the refractive index of which is n_a, is a layer comprising a mixture of a material having a higher refractive index than n_b and/or n_c and a material having a lower refractive index than n_b and/or n_c.

5. The organic electroluminescent device according to claim 1, wherein the intermediate conductive layer, the refractive index of which is n_a, comprises a material having a low refractive index and a transparent conductive material selected from oxides, nitrides, iodides and borides of metals.

6. The organic electroluminescent device according to claim 5, wherein the material having a low refractive index is a metal halide, and the transparent conductive material is a conductive metal oxide.

7. The organic electroluminescent device according to claim 1, wherein the absorption coefficient (unit:

1/μ

m) of the intermediate conductive layer, the refractive index of which is n_a, is 2.5 or less.

8. A display comprising the organic electroluminescent device of claim 1.

2. An organic electroluminescent device comprising:

a transparent electrode,

a counter electrode arranged opposite to the transparent electrode,

one or more intermediate conductive layers and a plurality of organic emitting layers sandwiching an intermediate conductive layer therebetween, the intermediate conductive layers and the organic emitting layers arranged between the transparent electrode and the counter electrode,

wherein the difference between n_a, and n_b and/or n_c is 0.2 or less when n_a is the refractive index of an intermediate conductive layer, n_b is the refractive index of a first organic emitting layer and n_c is the refractive index of a second organic emitting layer, the intermediate conductive layer sandwiched between the first and second organic emitting layers.