Biosignal Electrode Barrier Layer Design
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Solution Overview
Problem
Biosignal measurement electrodes with high salt content gel face rapid degradation due to chemical reactions between the conductive and barrier layers, leading to reduced shelf life and performance over time.
Innovation Solution
The electrode design features a barrier layer deposited on a flexible non-conductive substrate, with the conductive layer and gel layer positioned such that the gel covers only a part of the barrier layer, and a non-conductive foam element is placed on top of the conductive layer to restrict the gel's contact area, preventing direct contact between the gel and conductive layers and enhancing the barrier effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high salt content gel is used to maximize signal quality and reduce impedance, then measurement precision is improved, but the conductive and barrier layers undergo chemical reactions that reduce shelf life
Solution Approach 1:
A protective barrier layer is introduced between the high salt content gel and the conductive layer to prevent direct chemical reactions. This intermediary layer allows the gel to maintain high salt content for optimal signal quality while the barrier protects the conductive layer from degradation, thereby extending shelf life to at least 18 months.
2Ease of manufacture
If a thin barrier layer is used to allow gel contact with conductive layer, then ease of manufacture is improved, but the conductive layer performance deteriorates over time
Solution Approach 1:
A thin but protective barrier layer is deposited over the conductive layer. This thin film provides sufficient protection against gel-induced degradation while maintaining ease of manufacture through standard deposition processes. The barrier layer is thin enough to allow electrical signal transfer but sufficient to prevent chemical reactions that would deteriorate the conductive layer.
3Reliability
If gel covers the entire barrier layer, then electrical signal transfer is improved, but chemical reactions between gel and conductive layer increase
Solution Approach 1:
The gel layer is positioned to cover only specific areas of the barrier layer where electrical contact is needed, rather than covering the entire barrier layer. This localized approach maintains sufficient electrical signal transfer while minimizing the contact area between gel and conductive layer, thereby reducing chemical reactions and extending electrode shelf life.
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
This configuration significantly extends the shelf life of the electrodes to at least 18 months, with potential for up to 36 months, while maintaining equal or improved measurement performance by minimizing chemical reactions and maintaining a stable barrier between the high salt content gel and conductive layers.
Implementation Method 1
a barrier layer configured to protect the conductive layer and transfer electrical signals, wherein the barrier layer deposited on the substrate, the gel layer is deposited on the barrier layer so that the gel layer covers only a part of the barrier layer
Implementation Method 2
a conductive layer configured to transfer electrical signals
Implementation Method 3
a gel layer configured to transfer electrical signals
Data Source
AI summary
A sensor for measuring biosignals is provided. The sensor comprises at least one electrode comprising: a substrate comprising a flexible non-conductive material; a conductive layer configured to transfer electrical signals; a gel layer configured to transfer electrical signals; and a barrier layer configured to protect the conductive layer and transfer electrical signals, wherein the barrier layer deposited on the substrate, the gel layer is deposited on the barrier layer so that the gel layer covers only a part of the barrier layer, and the conductive layer is deposited over an area of the barrier layer which is outside of an area of the barrier layer on which the gel layer is deposited.