Conductive Fabric Circuit Layers for Low-Cost Flexible Heating

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Solution Overview

Problem

Conventional methods for creating conductive fabrics are costly due to the high expense of silver paste and the need for high metallic thread content to achieve desired conductivity, which compromises flexibility.

Innovation Solution

A conductive fabric is produced using a base cloth with a metallic seed layer and a chemical-plating layer, optionally covered with a carbon layer, formed through evaporation or sputtering and chemical plating, allowing for controlled conductivity and heat generation efficiency without the need for expensive silver paste.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If silver paste is used as conductive paste, then conductivity is improved, but manufacturing cost increases

Engineering Contradiction:
ImproveconductivityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention changes the material parameters by replacing silver paste with a multi-layer metal structure consisting of a first metal layer (high conductivity material like silver or copper) and a second metal layer (lower cost material like aluminum or zinc). This parameter change maintains the required conductivity while reducing manufacturing cost through material substitution and optimization of layer thicknesses.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If metallic thread content is increased to achieve desired conductivity, then conductivity is improved, but flexibility deteriorates

Engineering Contradiction:
ImproveconductivityVSAvoidflexibility
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The invention replaces the mechanical weaving/knitting of metallic threads with a deposited metal layer structure. Instead of mechanically inserting metallic threads into the fabric (which limits conductivity when flexibility is maintained), the invention uses vacuum deposition or sputtering to form thin metal layers directly on the fabric surface. This substitution of the mechanical system with a physical vapor deposition system enables high conductivity without compromising fabric flexibility.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If conventional printing method is used, then manufacturing simplicity is maintained, but conductivity and adhesion are insufficient

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidconductivity and adhesion
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The invention introduces a preliminary action step by forming a first metal layer (such as chromium, nickel, or copper) before applying the second metal layer. This preliminary metal layer serves as an adhesion promoter and diffusion barrier, ensuring strong bonding between the base fabric and the conductive metal layer. The preliminary deposition step improves both adhesion and conductivity while maintaining manufacturing simplicity through a standardized multi-layer deposition process.

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

The solution provides a cost-effective conductive fabric with enhanced conductivity and heat generation efficiency while maintaining flexibility, achieved by adjusting the metal content in the chemical-plating layer and incorporating a carbon layer for improved adhesion and thermal performance.

Implementation Method 1

the metallic seed layer is an evaporation-deposition layer or a sputter-deposition layer

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 2

the metallic seed layer is an evaporation-deposition layer or a sputter-deposition layer

Methodology Applied
Scientific EffectSputtering: Sputtering

Implementation Method 3

the chemical-plating layer is applied over the metallic seed layer

Methodology Applied
Scientific EffectChemical plating: Electroplating

Data Source

PatentEP3808868B1Conductive fabric and its preparation and applications
Publication Date: 2024.03.20 FORMOSA TAFFETA CO LTD
  • EP3808868B1 patent drawingFigure 1~2
  • EP3808868B1 patent drawingFigure 3~4
  • EP3808868B1 patent drawingFigure 5A~5B

AI summary

The present invention provides a conductive fabric comprising base cloth and a conductive metallic circuit structure formed on the surface of the base cloth. The conductive metallic circuit structure comprises at least one metallic seed layer and at least one chemical-plating layer. The metallic seed layer is an evaporation-deposition layer or a sputter-deposition layer and has a circuit pattern. The chemical-plating layer is applied over the surface of the metallic seed layer. The conductive fabric has improved conductivity and heat generation efficiency.