Stretchable Conductor With Segmented Islets For Body Movement

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Solution Overview

Problem

Current flexible conducting wires used in implantable medical devices lack sufficient flexibility and compliance to conform to body movements, leading to fractures and loss of conductivity when stretched beyond 10%-20%, and existing stretchable conductors have high electrical resistivity.

Innovation Solution

A compliant stretchable conductor is created using a wire or tube made of electrically insulating material with helically wound conductive leads featuring micrometer-sized Y-shaped micro-cracks that are not connected, forming an electrically conductive layer, and a method involving twisting and elongation of the wire followed by conductive material deposition to maintain conductivity during deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If continuous conductive material is deposited on insulating support, then electrical conductivity is maintained, but flexibility and stretchability are limited due to fractures beyond 10%-20% deformation

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

Solution Approach 1:

The conductive material is segmented into discrete islands rather than continuous layers. These conductive islands are distributed across the insulating support and connected through percolation paths, allowing the structure to accommodate deformation without fracturing while maintaining electrical conductivity through the network of connected islands.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the morphological parameters of the conductive material from continuous to discontinuous (island) structures. By controlling the size, distribution, and connectivity of these islands, the material can undergo large deformations while maintaining percolation-based electrical conductivity, thus resolving the contradiction between conductivity reliability and flexibility.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If conductive material layers are arranged helically around insulating support, then some flexibility is achieved, but degree of flexibility remains insufficient for full compliance with body movements

Engineering Contradiction:
ImproveflexibilityVSAvoidconductivity maintenance
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The helical conductive material is segmented into discrete islands along the helical path rather than forming continuous wires. This segmentation allows each island to independently accommodate local deformations while maintaining connectivity through percolation, enabling greater flexibility without sacrificing conductivity reliability.

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If conductive rubber with silver or carbon particles is used, then mechanical elasticity and stretchability are achieved, but electrical resistivity is very high and changes considerably with stretching

Engineering Contradiction:
Improvemechanical elasticityVSAvoidelectrical resistivity
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent creates a composite structure combining insulating material (providing mechanical elasticity and stretchability) with discrete conductive material islands (providing low electrical resistivity). The composite leverages the advantages of both materials: the insulating matrix provides compliance while the conductive islands maintain low resistivity through percolation connectivity, even during stretching.

Inventive Principle:
Principle #40Composite materials

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 high degree of flexibility and compliance while maintaining electrical conductivity even when stretched beyond 20%, with the micro-crack pattern allowing for percolation and re-establishment of contacts, ensuring finite and reproducible electrical conduction during repeated deformations.

Implementation Method 1

one or more electrical leads applied on said wire or tube, characterized in that one or more of said leads comprise a plurality of islets of conductive material between which there are micro-cracks that are micrometer size, Y-shaped and not connected to each other, forming an electrically conductive layer providing electrical conduction and/or electrical percolation

Methodology Applied
Scientific EffectElectrical percolation: Conduction (electrical)

Data Source

PatentEP2137741B1Stretchable conductor and method for producing the same
Publication Date: 2018.03.07 SORIN CRM
  • EP2137741B1 patent drawingFigure 1~2a
  • EP2137741B1 patent drawingFigure 2b~2c
  • EP2137741B1 patent drawingFigure 2d

AI summary

The present invention relates to a compliant deformable conductor and a method for producing the same, comprising a wire or a tube made of an electrically insulating material and one or more electrical leads applied on said wire or tube, wherein one or more of said leads comprise a plurality of islets of conductive material, forming an electrically conductive layer providing electrical conduction and/or electrical percolation.