Embedded Metal-Foil Electrodes for Low-Visibility Transparent LED Displays

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

The existing transparent LED displays using ITO electrodes face limitations due to high production costs, limited availability of indium, inconsistent resistance values, and increased visibility issues, which restrict their use in high-performance and cost-effective applications. Additionally, the use of Ag nanowires or transparent metal oxides results in high resistance and poor transmittance, limiting the area of the display, and the attachment force of solder on metal electrodes is compromised by surface blackening.

Innovation Solution

An embedded electrode substrate is developed using a metal foil pattern on an adhesive layer, with a blackening layer applied to the upper and side surfaces of the wiring electrode portion to reduce visibility and maintain solder attachment force, while the light emitting device mounted portion has a blackening layer only on the side surface. The metal foil pattern is embedded in the adhesive layer through heat-treating at 70°C to 100°C, optimizing resistance and visibility characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If ITO transparent electrode material is used, then transparency and electrical conductivity are achieved, but production cost increases and resistance values are inconsistent

Engineering Contradiction:
Improveresistance consistencyVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive ITO material with a cheaper metal foil (aluminum or copper) that can be disposed of after transferring the pattern, significantly reducing production cost while maintaining electrical conductivity and resistance consistency

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent creates a copy of the electrode pattern by transferring the metal foil pattern from a sacrificial substrate to the transparent substrate through adhesive layer interaction, achieving consistent resistance values without direct ITO deposition

Inventive Principle:
Principle #26Copying

2Ease of manufacture

If metal foil pattern is used to replace ITO, then manufacturing cost decreases and conductivity increases, but visibility and haze increase

Engineering Contradiction:
Improvemanufacturing costVSAvoidvisibility and haze
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the metal foil pattern from the visible surface by embedding it within the adhesive layer, removing the harmful visual effect while preserving the electrical conductivity function

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The metal foil pattern is nested within the adhesive layer structure, with the adhesive material surrounding and concealing the metal foil, thereby hiding the pattern from view while maintaining electrical functionality

Inventive Principle:
Principle #7Nested doll (Nesting)

3Object-affected harmful factors

If blackening layer is applied to metal electrode, then visibility is reduced, but solder attachment force decreases

Engineering Contradiction:
ImprovevisibilityVSAvoidsolder attachment force
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent applies different surface treatments to different regions: the wiring electrode portion receives blackening treatment for visibility reduction, while the light emitting device mounted portion maintains original metal surface for solder attachment, achieving local optimization of both properties

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent divides the metal foil pattern into functionally distinct segments: wiring electrodes with blackening layers for visibility control, and mounting electrodes without blackening for solder attachment, allowing independent optimization of each segment

Inventive Principle:
Principle #1Segmentation

4Object-affected harmful factors

If metal foil pattern is embedded in adhesive layer, then visibility is improved and resistance is optimized, but manufacturing process complexity increases

Engineering Contradiction:
ImprovevisibilityVSAvoidmanufacturing process
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent merges the pattern transfer process with the adhesive layer formation process, where the adhesive layer simultaneously serves as both the bonding medium and the embedding medium for the metal foil pattern, reducing process steps

Inventive Principle:
Principle #5Merging (Combining)

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 solution reduces manufacturing costs, maintains low resistance, and enhances visibility by minimizing pattern awareness, ensuring excellent resistance characteristics and attachment force for the transparent light emitting device display, while preventing haze and improving durability.

Implementation Method 1

an adhesive layer, and a wiring electrode portion and a light emitting device mounted portion which are embedded in the adhesive layer

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

the metal foil pattern is formed on an adhesive layer and then heat-treated at a temperature of 70°C to 100°C to manufacture an embedded electrode substrate in which the metal foil pattern is embedded in the adhesive layer

Methodology Applied
Scientific EffectHeat treatment: Heat Treatment

Data Source

PatentEP3651216B1Embedded electrode substrate for transparent light-emitting element display, and method for manufacturing same
Publication Date: 2024.03.13 LG CHEM LTD
  • EP3651216B1 patent drawingFigure 1
  • EP3651216B1 patent drawingFigure 2
  • EP3651216B1 patent drawingFigure 3

AI summary

An embedded electrode substrate for a transparent light emitting device display according to an embodiment of this application comprises: a transparent substrate; an adhesive layer provided on the transparent substrate; and a wiring electrode portion and a light emitting device mounted portion embedded in the adhesive layer and the wiring electrode portion comprises a first metal foil pattern and comprises a blackening layer on both an upper surface and a side surface of the first metal foil pattern, and the light emitting device mounted portion comprises a second metal foil pattern and comprises the blackening layer only on the side surface of the second metal foil pattern.