Flexible Conductive Lines With Dual-Modulus Layers

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Solution Overview

Problem

Flexible electronic devices face challenges in maintaining reliability and electrical characteristics when curved or bent, particularly due to the risk of cracks in conductive layers, which affects their flexibility and conductivity.

Innovation Solution

A flexible electronic device design featuring a base substrate with first and second conductive layers of different moduli, where the second conductive layer is overlapped with the first layer in one direction but not in another, enhancing flexibility and conductivity while preventing cracks when the device is curved.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a single conductive layer is used in flexible electronic devices, then the structure is simple and easy to manufacture, but the device lacks flexibility and suffers from cracks when curved

Engineering Contradiction:
Improvestructure simplicityVSAvoidcrack resistance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent employs a composite conductive structure consisting of a first conductive layer (e.g., ITO) and a second conductive layer (e.g., metal mesh or nanowire network) with different mechanical properties. The first layer provides good conductivity while the second layer enhances flexibility and crack resistance, creating a composite material system that resolves the contradiction between structural simplicity and reliability.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the physical parameters of the conductive layers by using materials with different moduli of elasticity. The first conductive layer has higher modulus for structural stability, while the second conductive layer has lower modulus for flexibility. This parameter differentiation allows the device to maintain both manufacturing ease and crack resistance when curved.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the conductive layer width is increased to reduce resistance, then electrical conductivity improves, but the device flexibility and bendability deteriorate

Engineering Contradiction:
Improveelectrical conductivityVSAvoidflexibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent uses a composite conductive structure where the first conductive layer provides low resistance through optimized width and material selection, while the second conductive layer (with lower modulus) provides flexibility. The combination allows the device to achieve good electrical conductivity without sacrificing bendability, as the second layer can accommodate deformation during flexing.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies different material properties to different regions of the conductive structure. The first conductive layer is designed with specific width and material characteristics for optimal conductivity, while the second conductive layer is strategically positioned and designed with different properties to provide localized flexibility enhancement at critical bending zones.

Inventive Principle:
Principle #3Local quality

3Reliability

If a dual conductive layer structure is implemented, then flexibility and crack resistance improve, but the device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improvecrack resistanceVSAvoidconductive layer structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a dual conductive layer composite structure where each layer has a specific function: the first layer (higher modulus) provides structural stability and conductivity, while the second layer (lower modulus) provides flexibility and crack resistance. This functional differentiation in the composite structure improves reliability while maintaining reasonable manufacturing complexity through clear division of labor between layers.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent segments the conductive function into two separate layers with distinct roles. The first conductive layer handles primarily electrical conduction and structural support, while the second conductive layer handles flexibility and crack prevention. This segmentation allows each layer to be optimized independently, improving overall reliability while making the manufacturing process more manageable through modular construction.

Inventive Principle:
Principle #1Segmentation

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 design improves the flexibility, mechanical stability, and reliability of the device by reducing the probability of open defects and voltage drop, resulting in improved electrical characteristics and resistance per unit length.

Implementation Method 1

The first and second conductive layers have a first modulus and a second modulus, respectively... A first width in the second direction of each of the first portions of the first conductive layer is smaller than a second width in the second direction of each of the second portions of the first conductive layer

Methodology Applied
Scientific EffectModulus of elasticity: Elasticity

Data Source

PatentEP3144768B1Flexible electronic device
Publication Date: 2024.02.28 SAMSUNG DISPLAY CO LTD
  • EP3144768B1 patent drawingFigure 1
  • EP3144768B1 patent drawingFigure 2A~2B
  • EP3144768B1 patent drawingFigure 3

AI summary

A flexible electronic device includes a base substrate and first and second lines disposed on the base substrate. The first and second lines extend in a first direction and are arranged in a second direction different from the first direction. Each of the first and second lines includes a first conductive layer including first portions and second portions alternately disposed with the first portions, and second conductive layers respectively overlapped with the first portions of the first conductive layer in a third direction substantially perpendicular to the first and second directions. The second conductive layer are not overlapped with the second portions of the first conductive layer in the third direction. The first and second conductive layers have a first modulus and a second modulus, respectively. A first width in the second direction of each of the first portions of the first conductive layer is smaller than a second width in the second direction of each of the second portions of the first conductive layer.