Organic EL display apparatus and method of manufacturing organic EL display apparatus

Patent metadata

Field	Value
Publication number	US-11114517-B2
Application number	US-201816767449-A
Country	US
Kind code	B2
Filing date	Mar 28, 2018
Priority date	Mar 28, 2018
Publication date	Sep 7, 2021
Grant date	Sep 7, 2021

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 electro luminescent (EL) display apparatus comprising:
a substrate having a surface on which a drive circuit comprising a thin film transistor is formed,
a planarizing layer including a first inorganic insulating layer and an organic insulating layer to planarize the surface of the substrate by covering the drive circuit, and
an organic light emitting element, the organic light emitting element comprising a first electrode being formed on a surface of the planarizing layer and connected, via a contact formed in the planarizing layer, to the drive circuit, an organic light emitting layer being formed on the first electrode, and a second electrode being formed on the organic light emitting layer,
wherein a surface of the organic insulating layer is formed such that a planarity thereof is brought to be greater than or equal to 20 nm and less than or equal to 50 nm in arithmetic average roughness Ra, and
wherein the first electrode is formed on only a region of the surface of the planarizing layer, in which the contact is not formed, and the organic light emitting layer is formed on only the first electrode, and the first electrode and the organic light emitting layer have substantially the same degree of surface roughness as a surface roughness of the planarizing layer, thereby, even in a microscopically planar state, a surface of the organic light emitting layer having no unevenness.

2. The organic EL display apparatus according to claim 1 , wherein the organic insulating layer is an acrylic resin or a polyimide resin.

3. The organic EL display apparatus according to claim 1 , wherein the organic insulating layer is a non-photosensitive resin.

4. The organic EL display apparatus according to claim 1 , wherein the planarizing layer has a three-layer structure in which a second inorganic insulating layer with substantially the same degree of surface roughness as that of the organic insulating layer is formed on the organic insulating layer.

5. The organic EL display apparatus according to claim 1 , wherein the organic light emitting element is a bottom emission type light emitting element in which the thin film transistor is not formed at a region right below the organic light emitting layer and light is extracted from a substrate end, or a top emission type light emitting element in which the thin film transistor is also formed at a region right below the organic light emitting layer and light is extracted from the second electrode.

6. The organic EL display apparatus according to claim 1 , wherein a normal direction of the surface of the organic light emitting layer of each pixel matches a normal direction of a display screen.

7. The organic EL display apparatus according to claim 1 , wherein each of the first electrode and the organic light emitting layer has a surface roughness of greater than or equal to 20 nm and less than or equal to 50 nm in arithmetic average roughness Ra.

8. A method of manufacturing an organic electro luminescent (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;
polishing a surface of the organic insulating layer, by chemical mechanical polishing (CMP), such that a planarity thereof is brought to be greater than or equal to 20 nm and less than or equal to 50 nm in arithmetic average roughness Ra;
forming a contact hole in the organic insulating layer and the first inorganic insulating layer, the contact hole to reach 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 at a given region in which the contact hole is not formed, on a surface of the organic insulating layer, the first electrode with substantially the same degree of surface roughness as a surface roughness of the organic insulating layer;
forming an organic light emitting layer with substantially the same degree of surface roughness as a surface roughness of the first electrode on only the first electrode, a normal direction of a surface of the organic light emitting layer matching a normal direction of a display screen; and
forming a second electrode on the organic light emitting layer.

9. The method of manufacturing an organic EL display apparatus according to claim 8 , wherein a second inorganic insulating layer with the same degree of surface roughness as that of the organic insulating layer is formed on the organic insulating layer and the contact hole is collectively formed in a three-layer structure comprising the second inorganic insulating layer, the organic insulating layer, and the first inorganic insulating layer.

10. The method of manufacturing an organic EL display apparatus according to claim 8 , wherein polishing, by CMP, the surface of the organic insulating layer is carried out with a neutral Ceria-based polishing material or a fumed silica-based slurry, along with water and alcohol.

11. The method of manufacturing an organic EL display apparatus according to claim 8 , wherein the forming of the contact hole is carried out by dry etching.

Assignees

• Sakai Display Products Corp

Inventors

• Kishimoto Katsuhiko

Classifications

• H10K59/124

  Insulating layers formed between TFT elements and OLED elements · CPC title

• H10D86/451 Primary

  characterised by the compositions or shapes of the interlayer dielectrics · CPC title

• 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