Conductive Gel Electrodes for Human Interfaces

Solution Overview

Problem

Conductive human interfaces face challenges in providing comfortable and effective signal communication with the skin due to the stiffness of metallic electrodes, while polymers are non-conductive, necessitating a compliant and conductive material solution.

Innovation Solution

A conductive human interface is formed using an insulating elastomeric body with embedded compliant electrodes made of electrically conductive gel, comprising a polymeric material and conductive additive dispersed throughout, with controlled bulk DC resistance and particle size to ensure flexibility and conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If metallic electrodes are used, then electrical conductivity is improved, but mechanical compliance and comfort deteriorate

Engineering Contradiction:

Improveelectrical conductivityVSAvoidmechanical compliance

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The electrode is constructed as a composite material combining a polymeric matrix with dispersed conductive particles (such as carbon black, metal oxides, or conductive polymers). This composite structure provides both the electrical conductivity needed for signal communication and the mechanical compliance of polymer materials for comfortable skin contact.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The electrical conductivity of the polymer electrode is adjusted by controlling the concentration, size, and distribution of conductive particles within the polymer matrix. By optimizing these parameters, the electrode achieves sufficient conductivity for TENS and EMG applications while maintaining the soft, compliant characteristics of the polymer base material.

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If polymer materials are used, then mechanical compliance is improved, but electrical conductivity deteriorates

Engineering Contradiction:

Improvemechanical complianceVSAvoidelectrical conductivity

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The electrode is constructed as a composite material combining a polymeric matrix with dispersed conductive particles (such as carbon black, metal oxides, or conductive polymers). This composite structure provides both the electrical conductivity needed for signal communication and the mechanical compliance of polymer materials for comfortable skin contact.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The electrical conductivity of the polymer electrode is adjusted by controlling the concentration, size, and distribution of conductive particles within the polymer matrix. By optimizing these parameters, the electrode achieves sufficient conductivity for TENS and EMG applications while maintaining the soft, compliant characteristics of the polymer base material.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If conductive additive is increased, then electrical conductivity is improved, but material hardness and rigidity increase

Engineering Contradiction:

Improveelectrical conductivityVSAvoidmaterial hardness

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The electrical conductivity of the polymer electrode is adjusted by controlling the concentration, size, and distribution of conductive particles within the polymer matrix. By optimizing these parameters, the electrode achieves sufficient conductivity for TENS and EMG applications while maintaining the soft, compliant characteristics of the polymer base material.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The conductive particles are distributed heterogeneously within the polymer matrix, with higher concentrations localized in specific regions to achieve necessary conductivity pathways. This localized distribution allows the bulk material to remain soft and compliant while providing sufficient conductivity at the electrode-skin interface.

Inventive Principle:

Principle #3Local quality

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 comfortable, long-term contact with the skin, maintaining signal integrity and reducing mechanical stress, allowing for effective communication of EMG signals and control of assistive devices with improved durability and skin compatibility.

Implementation Method 1

an electrode embedded in the insulating body. The electrode can be formed of electrically conductive gel including a polymeric material and conductive additive material dispersed in the polymeric material

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP3522779B1Conductive human interfaces comprising electrodes formed using electrically conductive gel

Publication Date: 2022.10.26 WILLOWWOOD GLOBAL LLC

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AI summary

A conductive human interface includes an insulating body of elastomeric material and a compliant electrode embedded in the insulating body. The electrode is formed from an electrically conductive gel including a polymeric material and conductive particles dispersed in the polymeric material. The conductive particles can be included in the gel in an amount that is not more than about 10% by weight.