Electroluminescence structure

• US 4,418,118 A
• Filed: 04/08/1982
• Issued: 11/29/1983
• Est. Priority Date: 04/22/1981
• Status: Expired due to Fees

• Current Assignee: Elkotrade AG
• Original Assignee: OY Lohja AB
• Inventors: Lindors, Sven G.
• Primary Examiner(s): Robinson, Ellis P.
• Application Number:
  US06/366,573
• Time in Patent Office: 600 Days
• Field of Search: 428/917, 428/336, 428/701, 428/699, 428/698, 428/432, 428/408, 428/323, 427/66, 350/357, 313/503, 313/499, 313/510, 313/505, 313/506, 313/509
• US Class Current: 428/336
• CPC Class Codes: H05B 33/22 characterised by the chemical or physical composition or the arrangement of auxiliary dielectric or reflective layers
• CPC Class Codes: H05B 33/26 characterised by the composition or arrangement of the conductive material used as an electrode
• CPC Class Codes: Y10S 428/917 Electroluminescent
• CPC Class Codes: Y10T 428/25 Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
• CPC Class Codes: Y10T 428/265 1 mil or less
• CPC Class Codes: Y10T 428/30 Self-sustaining carbon mass or layer with impregnant or other layer

Abstract

In the present application, an electroluminescence structure is described which comprises, among other things, a first electrode layer (2) prepared by means of the thin film technique, and a second electrode layer (7, 7'"'"') prepared by means of a thick film technique, as well as a luminescence layer (4) disposed between the electrode layers. The use of a thick film directly as the electrode of a thin film structure causes problems resulting from inhomogeneous contact of the thick film material. According to the invention, these problems have been solved so that between the second electrode layer (7, 7'"'"') and the luminescence layer (4), a very thin additional layer (6) of resistive material is disposed which is bounded by the second electrode layer (7, 7'"'"') and which forms a spreading resistance for the point contacts of the conductive particles in the second electrode layer (7, 7'"'"'). In this resistance the inhomogeneous current density is homogenized before reaching the luminescence layer (4).

Claims

1. An electroluminescence structure including a substrate member, acid structure further comprising:

a first electrode layer disposed on the substrate;

a second electrode layer forming a thick film comprising a binder and conductive particles; and

a luminescence layer and at least first and second additional layers disposed between the first and the second electrode layers;

wherein said first additional layer is disposed between a said electrode layer and the luminescence layer and has at least one of the functions of current limitation and chemical protection; and

wherein said second additional layer is formed of resistive material having a thickness of the order of about 10-100 nm, is disposed between the second electrode layer and the luminescence layer, and is bounded by the second electrode layer so as to form a spreading resistance for the point contacts formed by the conductive particles in the second electrode layer for homogenizing inhomogeneous current densities before the currents reach the luminescence layer.

2. An electroluminescence structure as claimed in claim 1, wherein the second electrode layer is made of a paste containing graphite particles.

3. An electroluminescence structure as claimed in claim 1, wherein the second additional layer of resistive material is made of TiO₂, In₂ O₃, or SnO₂.

4. An electroluminescence structure as claimed in claim 3, wherein the thickness of the layer of resistive material is of the order of about 10 to 100 nm, preferably about 50 nm.

5. An electroluminescence structure as claimed in claim 1, wherein the second additional layer of resistive material is made of indium-tin oxide (I_x Sn_y O_z).

6. An electroluminescence structure as claimed in claim 5, wherein the layer of resistive material has a thickness of a few atom layers.

7. An electroluminescence structure as claimed in claim 1, wherein the second additional layer of resistive material is made of a carbon film.

8. An electroluminescence structure as claimed in claim 1, wherein the second additional layer of resistive material is prepared by depositing by means of the ALE (Atomic Layer Epitaxy) method.