OLED Composite Electrode Plasma Shielding

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Solution Overview

Problem

Current top-emitting AMOLED manufacturing faces challenges with thin metal transparent electrodes experiencing pressure fall issues and plasma-induced heat effects, leading to low light-emitting efficiency and short lifetimes, while thick transparent conducting oxides can cause electricity leakage during sputtering.

Innovation Solution

A composite transparent electrode structure is introduced, comprising a metal layer, a transparent conducting oxide layer, and a dielectric cover layer with a high dielectric constant (>10) positioned between the metal and transparent conducting oxide layers, where the cover layer reduces plasma effects and protects the metal layer during sputtering, enhancing electrical conductivity and light extraction efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a thin metal transparent electrode is used, then the pressure fall issue is reduced and light extraction efficiency is improved, but the electrode experiences plasma-induced heat effects and damage during sputtering

Engineering Contradiction:

Improvelight extraction efficiencyVSAvoidplasma-induced heat effects and damage

Core Design Contradiction:

Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

A dielectric cover layer with high dielectric constant (ε>10) is introduced as an intermediary between the metal layer and transparent conducting oxide layer. This cover layer shields the metal layer from plasma damage during sputtering while maintaining electrical conductivity through controlled holes, and improves light extraction efficiency through its optical properties.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The electrode structure uses a composite multi-layer design combining metal layer, dielectric cover layer, and transparent conducting oxide layer. Each layer serves specific functions: metal provides conductivity, dielectric protects from plasma, and TCO provides transparency and additional conductivity pathways.

Inventive Principle:

Principle #40Composite materials

2Reliability

If a thick transparent conducting oxide layer is used during sputtering, then electrical conductivity is improved, but electricity leakage occurs

Engineering Contradiction:

Improveelectrical conductivityVSAvoidelectricity leakage

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The dielectric cover layer is designed with localized holes that allow electrical conduction only where needed. The cover layer maintains insulation in most areas while providing controlled electrical pathways through the holes, preventing electricity leakage while ensuring sufficient conductivity.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The dielectric constant of the cover layer is optimized to be greater than 10, which enhances its ability to shield electric fields and control electrical behavior. This parameter optimization allows the structure to achieve good electrical conductivity without leakage.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If the metal layer thickness is increased to reduce pressure fall, then electrical conductivity is improved, but the plasma effect and damage to the metal layer increase

Engineering Contradiction:

Improveelectrical conductivityVSAvoidmetal layer integrity

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The dielectric cover layer is deposited beforehand to protect the metal layer from plasma damage during subsequent sputtering of the transparent conducting oxide layer. This protective layer prevents metal layer degradation while maintaining the desired electrical conductivity.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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

The composite electrode structure effectively reduces pressure fall and plasma-induced damage, improving light extraction efficiency and extending the lifetime of OLEDs by providing a protective layer during sputtering and increasing electrical conductivity.

Implementation Method 1

a transparent cover layer located between the metal layer and the transparent conducting oxide layer, wherein the metal layer is electrically connected to the transparent conducting oxide layer

Methodology Applied

Scientific EffectDielectric: Dielectric

Implementation Method 2

the transparent conducting oxide layer is located on a side of the metal layer away from the organic light-emitting functional layer

Methodology Applied

Scientific EffectSputtering: Sputtering

Implementation Method 3

the metal layer is electrically connected to the transparent conducting oxide layer

Methodology Applied

Scientific EffectElectrical Conduction: Conduction (electrical)

Implementation Method 4

enhancing electrical conductivity and light extraction efficiency

Methodology Applied

Scientific EffectLight extraction:

Data Source

PatentEP3584852B1OLED comprising a composite transparent electrode and manufacturing method thereof

Publication Date: 2023.05.10 BOE TECHNOLOGY GROUP CO LTD

Figure 1A~1C
Figure 2~4

AI summary

A composite transparent electrode, an organic light-emitting diode and a method for manufacturing thereof, an array substrate and a display device. In the composite transparent electrode, a cover layer (12) is provided between a metal layer (11) and a transparent conducting oxide layer (13), the transparent conducting oxide layer (13) is electrically connected to the metal layer (11). The composite transparent electrode can reduce damages to the metal layer (11) or decrease pressure fall during a sputtering process.