Organic thin film light-emitting device having second electrodes layer covering periphery of first electrodes layer

• US 5,896,006 A
• Filed: 09/26/1997
• Issued: 04/20/1999
• Est. Priority Date: 09/27/1996
• Status: Expired due to Term

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: NEC Corporation
• Inventors: Tanaka, Taizo, Kusaka, Teruo
• Primary Examiner(s): Patel, Vip
• Application Number:
  US08/938,294
• Time in Patent Office: 571 Days
• Field of Search: 313/500, 313/501, 313/503, 313/505, 313/506, 313/512
• US Class Current: 313/506
• CPC Class Codes: H10K 50/824 combined with auxiliary electrodes
• CPC Class Codes: H10K 59/17 Passive-matrix OLED displays
• CPC Class Codes: H10K 59/80522 combined with auxiliary electrodes

Abstract

Metal electrodes (cathode) are made from a plurality of materials wherein they are not simply superposed one another along the sectional direction, but the metal electrodes (cathode) are in contact with an organic thin film in such that they exhibit a difference in magnitude of work functions dependent upon their disposed positions in the plane. More specifically, a local metal electrode being in contact with the organic thin film inside a light-emitting device in the plane is formed from a material having a small work function, while the peripheral metal electrode which encloses the local metal electrode, wiring sections other than the light-emitting device and the like are formed from materials each having a lager work function than that of the local metal electrode.

Claims

1. An organic thin film electric field light-emitting device, comprising:

a transparent electrode formed on a first surface of an organic thin film;

metal electrodes of first and second layers formed on a second surface of said organic thin film; and

a light-emitting region formed in said organic thin film, into which carriers are injected from said transparent electrode and said metal electrodes of said first and second layers to emit lights;

wherein the whole periphery of said metal electrode of said first layer is covered on said organic thin film by said metal electrode of said second layer, and is smaller in work function than said metal electrode of said second layer.

2. The light-emitting device as defined in claim 1, wherein:

said metal electrode of said first layer is formed from two or more electrodes each having a different work function.

3. A display panel, comprising:

a plurality of organic thin film electric field light-emitting devices arranged in a predetermined pattern;

wherein each of said plurality of organic thin film electric field light-emitting devices, comprises;

a transparent electrode formed on a first surface of an organic thin film;

metal electrodes of first and second layers formed on a second surface of said organic thin film; and

a light-emitting region formed in said organic thin film, into which carriers are injected from said transparent electrode and saidmetal electrodes of said first and second layers to emit lights;

wherein the whole periphery of said metal electrode of said first layer is covered on said organic thin film by said metal electrode of said second layer, and is small in work function than said metal electrode of said second layer.

4. The display panel as defined in claim 3, wherein:

said metal electrode of said first layer is formed from two more electrodes each having a different work function.