Organic EL display device in which the light of small sub-pixels are properly guided, and manufacturing method therefor

Patent metadata

Field	Value
Publication number	US-12310187-B2
Application number	US-202318219745-A
Country	US
Kind code	B2
Filing date	Jul 10, 2023
Priority date	Mar 28, 2018
Publication date	May 20, 2025
Grant date	May 20, 2025

Abstract

The present invention is equipped with: a substrate ( 10 ) that has a surface upon which a drive circuit containing a TFT ( 20 ) is formed; a planarizing layer ( 30 ) that makes the surface of the substrate ( 10 ) planar by covering the drive circuit; and an organic light emitting element ( 40 ) that is provided with a first electrode ( 41 ) formed upon the surface of the planarization film and connected to the drive circuit, an organic light emitting layer ( 43 ) formed upon the first electrode, and a second electrode ( 44 ) formed upon the organic light emitting layer. In addition, the planarizing layer ( 30 ) includes a first inorganic insulating layer ( 31 ) and an organic insulating layer ( 32 ) that are layered upon the drive circuit, and the surface of the organic insulating layer ( 32 ) is formed with an arithmetic mean roughness Ra of no more than 50 nm.

First claim

The invention claimed is:

1. An organic electroluminescent (EL) display apparatus comprising:
a substrate having a surface on which a drive circuit comprising a thin film transistor is formed;
a planarizing layer to planarize the surface of the substrate by covering the drive circuit;
a conductor layer being embedded into a contact hole which is formed in the planarizing layer so as to reach the thin film transistor; and
an organic light emitting element comprising a first electrode being formed, as a physical deposition film, on a surface of the planarizing layer and connected to the conductor layer, an organic light emitting layer being formed, as a vacuum vapor deposition film, on the first electrode, and a second electrode being formed on the organic light emitting layer,
wherein the planarizing layer comprises a first inorganic insulating layer and an organic insulating layer being formed on the first inorganic insulating layer,
the organic light emitting layer comprises a plurality of sub-pixels to emit light of red (R), green (G), and blue (B), and
each of the first electrode and the organic light emitting layer of the organic light emitting element is formed such that a surface of the first electrode and a surface of the organic light emitting layer are formed in substantially the same degree of surface roughness as a surface roughness of the planarizing layer, and such that, in a cross section view of the organic light emitting element, a contour of an upper surface of the organic light emitting layer and a contour of an upper surface of the first electrode are substantially the same shape in each sub-pixel in the plurality of sub-pixels, thereby the organic light emitting layer being formed in a substantially uniform thickness in each sub-pixel in the plurality of sub-pixels.

2. The organic EL display apparatus according to claim 1 , wherein the organic light emitting element is a top emission type light emitting element in which light is extracted from a second electrode end.

3. The organic EL display apparatus according to claim 1 , wherein the thin film transistor comprises a low temperature polysilicon layer.

4. The organic EL display apparatus according to claim 1 , wherein the organic light emitting layer is formed in the substantially uniform thickness throughout the organic light emitting layer in each sub-pixel in the plurality of sub-pixels.

5. A method of manufacturing an organic electroluminescent (EL) display apparatus, the method comprising:
forming a drive circuit on a substrate, the drive circuit comprising a thin film transistor (TFT);
forming, on a surface of the drive circuit, a first inorganic insulating layer and an organic insulating layer;
forming a contact hole in the organic insulating layer and the first inorganic insulating layer, such that the contact hole reaches the TFT;
embedding a metal at an interior of the contact hole and forming a first electrode continuously to the metal embedded into the contact hole by using a physical deposition at a given region in which the contact hole is not formed, on a surface of the organic insulating layer, the first electrode having, not only substantially the same degree of surface roughness as a surface roughness of the organic insulating layer, but also a substantially uniform thickness within a sub-pixel in each of sub-pixels of red (R), green (G), or blue (B);
forming an organic light emitting layer on the first electrode by using a vacuum vapor deposition, the organic light emitting layer having substantially the same degree of surface roughness as the surface roughness of the first electrode, such that, in a cross section view of the organic light emitting layer, a contour of an upper surface of the organic light emitting layer and a contour of an upper surface of the first electrode are substantially the same shape in each of the sub-pixels, thereby the organic light emitting layer being formed in a substantially uniform thickness in each of the sub-pixels; and
forming a second electrode on the organic light emitting layer, thereby forming an organic light emitting element comprising the first electrode, the organic light emitting layer, and the second electrode.

6. The method according to claim 5 , wherein the organic light emitting element is formed to be a top emission type light emitting element in which light is extracted from a second electrode end.

7. The method according to claim 5 , wherein the TFT comprises a low temperature polysilicon layer.

8. The method according to claim 5 , wherein the organic light emitting layer is formed in the substantially uniform thickness throughout the organic light emitting layer in each of the sub-pixels.

Assignees

• Sakai Display Products Corp

Inventors

• Kishimoto Katsuhiko

Classifications

• H10D86/421

  having a particular composition, shape or crystalline structure of the active layer · CPC title

• H10D86/0223

  comprising crystallisation of amorphous, microcrystalline or polycrystalline semiconductor materials · CPC title

• H10D86/60

  wherein the TFTs are in active matrices · CPC title

• H10D30/6745

  Polycrystalline or microcrystalline silicon · CPC title

• H10D30/6731

  Top-gate only TFTs · CPC title