Composite Electrode Structure for OLED Brightness Uniformity

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Solution Overview

Problem

The high resistance of oxide-based transparent electrodes in electronic devices, such as OLED lighting, leads to non-uniform current distribution and thermal degradation, reducing device lifespan and brightness uniformity, especially as device size increases.

Innovation Solution

A metal auxiliary electrode pattern with a light blocking pattern and organic insulating pattern is implemented, where the light blocking pattern has a larger line width than the auxiliary electrode pattern, and both are formed using different metals with varying etching speeds, ensuring electrical connectivity and insulation stability, even with increased thickness of the auxiliary electrode pattern.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a transparent electrode based on metal oxide is used, then transparency is achieved, but resistance is high causing non-uniform current distribution and thermal degradation

Engineering Contradiction:
ImprovetransparencyVSAvoidresistance
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent combines a transparent electrode (metal oxide layer) with a reflective electrode (metal layer) to form a composite electrode structure. This composite structure maintains the transparency of the metal oxide while adding the low resistance of the metal layer, thereby resolving the contradiction between transparency and resistance. The reflective electrode layer is formed on the metal oxide layer, creating a multi-layer composite that delivers both optical and electrical performance.

Inventive Principle:
Principle #40Composite materials

2Area of stationary object

If the device size is increased, then screen area is enlarged, but carrier crowding phenomenon causes non-uniform current distribution

Engineering Contradiction:
Improvescreen areaVSAvoidcurrent distribution uniformity
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The electrode structure is segmented into multiple functional layers: a transparent electrode layer and a reflective electrode layer. This segmentation allows each layer to perform its specific function - the transparent electrode for light transmission and the reflective electrode for current distribution. By dividing the electrode into separate layers rather than using a single uniform electrode, the patent achieves uniform current distribution across large screen areas while maintaining transparency.

Inventive Principle:
Principle #1Segmentation

3Reliability

If a metal auxiliary electrode pattern is added, then resistance is reduced, but device complexity increases

Engineering Contradiction:
ImproveresistanceVSAvoidelectrode structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the auxiliary electrode function with the existing electrode structure by forming a reflective electrode layer on top of the transparent electrode layer. Instead of adding a separate auxiliary electrode pattern that would increase complexity, the solution combines multiple functions (transparency, reflectivity, and low resistance) into a single integrated multi-layer structure. This merging approach reduces resistance while avoiding additional structural complexity.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3474295B1Electrode structure, electronic device comprising same and method for manufacturing same
Publication Date: 2021.08.25 LG CHEM LTD
  • EP3474295B1 patent drawingFigure 1
  • EP3474295B1 patent drawingFigure 2
  • EP3474295B1 patent drawingFigure 3

AI summary

The present specification relates to an electrode structure, an electronic device including the electrode structure, and a method of manufacturing the electrode structure.