OLED Pixel Electrode Surface Treatment for Interfacial Resistance

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Solution Overview

Problem

The interfacial resistance between the pixel electrode and the intermediate layer in organic light-emitting display devices increases due to hydrophobic materials used in the pixel-defining layer, leading to efficiency deterioration.

Innovation Solution

A method involving the use of a hydrophobic material layer with fluorine groups on the pixel electrode, followed by surface treatment to remove fluorine groups from the pixel electrode surface, maintaining hydrophobicity on the pixel-defining layer while reducing interfacial resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a hydrophobic material is used in the pixel-defining layer to prevent ink residue formation, then ink residue formation is prevented, but the interfacial resistance between the pixel electrode and the intermediate layer increases

Engineering Contradiction:
Improveink residue formationVSAvoidinterfacial resistance
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent applies different surface properties to different regions of the pixel-defining layer. The upper surface maintains hydrophobicity to prevent ink residue, while the lower surface (facing the pixel electrode) is made hydrophilic through plasma treatment to reduce interfacial resistance. This local differentiation of surface properties resolves the contradiction between preventing ink residue and maintaining low interfacial resistance.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent performs plasma treatment on the lower surface of the pixel-defining layer before depositing the intermediate layer. This preliminary action modifies the surface energy and creates a hydrophilic surface that promotes good adhesion and low interfacial resistance, ensuring optimal interface properties before the intermediate layer is formed.

Inventive Principle:
Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach prevents ink residue formation and maintains low interfacial resistance, enhancing the efficiency of the organic light-emitting display device.

Implementation Method 1

surface treatment to remove fluorine groups from the pixel electrode surface

Methodology Applied
Scientific EffectPlasma treatment: Plasma

Data Source

PatentEP2819173B1Method of manufacturing an organic light-emitting display device
Publication Date: 2022.06.08 SAMSUNG DISPLAY CO LTD
  • EP2819173B1 patent drawingFigure 1~3
  • EP2819173B1 patent drawingFigure 4~6
  • EP2819173B1 patent drawingFigure 7~9

AI summary

A method of manufacturing an organic light-emitting display device is provided. The method includes forming a pixel electrode, forming a hydrophobic material layer on the pixel electrode, wherein the hydrophobic material layer includes a hydrophobic material, forming a pixel-defining layer by patterning the hydrophobic material layer, so as to expose at least a portion of the pixel electrode, and removing the hydrophobic material on the exposed portion of the pixel electrode using surface treatment.