Zigzag Stretchable Electrode Conductor for Medical Implants

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Solution Overview

Problem

Existing expandable electrode arrays in medical implants face limitations due to tensile forces between conductive layers and stretchable materials, leading to conductor lift-off and reduced service life, especially with frequent elongations.

Innovation Solution

An electrode conductor arrangement featuring a carrier and cover made from substantially inextensible materials, cut in a zigzag or meandering shape to match the conductor tracks, minimizing tensile forces and ensuring long-term reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conductive layers are applied to stretchable materials and encapsulated within them, then the electrode array can be stretched, but tensile forces arise between the metal layers and the stretchable base material, limiting the maximum number of stretching cycles and maximum strains

Engineering Contradiction:
ImprovestretchabilityVSAvoidconductor attachment stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The base material is segmented into multiple discrete support structures (posts or pillars) rather than a continuous stretchable layer. These segmented supports allow localized deformation while maintaining overall structural integrity, preventing the tensile forces that would cause conductor detachment in a continuous stretchable material.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The support structures are given a curved or rounded geometry (spheroidal posts or pillars) rather than flat planar surfaces. This curvature allows the supports to flex and deform elastically during stretching cycles, absorbing mechanical stress without creating concentrated tensile forces at the conductor-interface boundary.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Duration of action of moving object

If the base material is made stretchable to allow elongation, then the electrode array can expand, but the maximum number of stretching cycles is limited due to conductor lift-off

Engineering Contradiction:
Improvenumber of stretching cyclesVSAvoidconductor integrity
Core Design Contradiction:
Duration of action of moving objectVSReliability

Solution Approach 1:

The rigid or semi-rigid support structures are positioned beforehand to provide mechanical cushioning and stress distribution before stretching occurs. These pre-positioned supports absorb and distribute the mechanical stresses of stretching, preventing the cumulative damage that would lead to conductor lift-off after multiple cycles.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

While the overall base material is stretchable, the conductor support structures use rigid or semi-rigid materials that provide a flexible yet stable platform. This creates a hierarchical structure where the thin film conductors remain stable on rigid supports, while the overall assembly can still expand through the flexible base material.

Inventive Principle:
Principle #30Flexible shells and thin films

3Adaptability or versatility

If conductive traces are laid out on stretchable base material, then the electrode array can be expanded, but tensile forces can cause the conductive traces to detach, creating migration paths for electrolytes

Engineering Contradiction:
Improvearray expandabilityVSAvoidelectrolyte migration
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The rigid or semi-rigid support structures serve as an intermediary between the stretchable base material and the conductive traces. This intermediate layer decouples the mechanical deformation of the base material from the conductor layer, preventing direct tensile forces from acting on the conductors and eliminating the pathways for electrolyte migration that would otherwise form during stretching.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3292885B1Stretchable electrode conductor assembly and medical implant
Publication Date: 2019.07.17 BIOTRONIK SE & CO KG
  • EP3292885B1 patent drawingFigure 1A~1B
  • EP3292885B1 patent drawingFigure 2~3
  • EP3292885B1 patent drawingFigure 4

AI summary

Stretchable electrode conductor arrangement for a medical implant, comprising at least one zigzag or meandering conductor on an insulating carrier and with an insulating cover tightly connected to the carrier with embedding of the conductor, wherein the carrier is made of a substantially non-stretchable material and is cut in a zigzag or meandering shape to conform to the contour of the conductor or conductors.