High Impedance Dielectric Adhesive for Biomedical Sensor Signal Detection
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Solution Overview
Problem
Conventional electro-cardiogram (ECG) systems using ionically conductive hydrogels face limitations in humidity control, reusability, and cost, with low impedance leading to signal interference and reduced sensitivity, necessitating the development of a more effective and economical biomedical sensor system.
Innovation Solution
A high impedance continuous signal receptive material (SRM) is used as a common attachment adhesive for multiple high impedance electrodes, employing capacitive coupling to detect time-varying signals without ionic conductivity, allowing for a lower-cost, more sensitive, and versatile sensor system with improved signal specificity and reduced noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ionically conductive hydrogel is used as adhesive material, then electrical conductivity is improved, but measurement precision deteriorates due to low impedance causing signal interference
Solution Approach 1:
The patent changes the electrical impedance parameter from low (conductive hydrogel) to high (dielectric adhesive), fundamentally altering the signal transmission mechanism from ionic conduction to capacitive coupling. This parameter change resolves the contradiction by eliminating ionic interference while maintaining signal detection capability through the body's natural electrical properties.
Solution Approach 2:
The patent replaces the ionic conduction mechanism (chemical/electrochemical system) with a capacitive coupling mechanism (electrical field system). By substituting the signal transmission mechanism from ion flow through hydrogel to electric field coupling through dielectric material, the system achieves both good electrical contact and high signal fidelity without ionic interference.
2Measurement precision
If multiple electrodes are used in harness system, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent merges the adhesive function and the signal transmission function into a single integrated dielectric adhesive layer. This consolidation eliminates the need for separate conductive hydrogel layers and simplifies the electrode-harness interface, reducing device complexity while maintaining multiple electrode detection capability for precise signal measurement.
Solution Approach 2:
The dielectric adhesive material serves multiple functions simultaneously: it provides mechanical adhesion between electrode and skin, acts as an electrical insulator to prevent signal interference between adjacent electrodes, and enables capacitive coupling for signal transmission. This multi-functionality reduces the number of components needed and simplifies the overall system design.
3Ease of manufacture
If conventional hydrogel adhesive is used, then ease of manufacture is improved, but productivity deteriorates due to reusability limitations and humidity control requirements
Solution Approach 1:
The patent employs a disposable dielectric adhesive electrode design that eliminates the need for reusability and humidity control. Each electrode can be independently manufactured and applied without concern for material degradation or environmental conditions, significantly improving productivity by eliminating cleaning, storage, and humidity control requirements associated with reusable hydrogel systems.
Solution Approach 2:
The patent changes the material properties from hydrogel (water-based, humidity-sensitive) to dielectric adhesive (water-insensitive, stable). This parameter change in material composition eliminates the fundamental limitations of hydrogel regarding reusability and environmental sensitivity, allowing for simpler manufacturing and higher productivity through disposable single-use electrodes.
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 high impedance SRM system provides enhanced sensitivity, reduced noise, and cost-effectiveness by allowing multiple electrodes to be placed on a single substrate, improving signal fidelity and ease of application, while avoiding the need for expensive silver/silver chloride contacts and reducing manufacturing complexity.
Implementation Method 1
an alternating current signal on one side of the composite may be capacitively coupled to the other side of the composite by having the dielectric properties of the material change with the application of an alternating current field (e.g., exhibits dielectric dispersion) such that a charge is released from the composite at the other side of the composite responsive to the changing dielectric properties
Implementation Method 2
employing capacitive coupling to detect time-varying signals without ionic conductivity
Data Source
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Figure 3A~3B
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AI summary
A biomedical sensor system is disclosed that includes a plurality of electrodes (50) and a contiguous adhesive material (52) that is in contact with each of the plurality of electrodes. The adhesive material has a high impedance and is dielectric yet changes its dielectric properties in the presence of biomedical signals. The adhesive material may include a polymeric material and a polar material that is dispersed within the polymeric material. The system may be adapted for ECG analysis.