Quadra-polar Concentric Ring Biomedical Electrode for High-Resolution Signal Acquisition
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Solution Overview
Problem
Conventional biomedical electrodes suffer from low spatial resolution and reference electrode issues due to blurring effects from varying conductivities in the body and require electrolyte gels, which are unpleasant and prone to smearing, leading to movement artifacts and toxicological concerns.
Innovation Solution
The development of quadra-polar concentric ring electrodes with specific diameter and thickness ratios for the conductive discs and rings, along with optimal spacing, to enhance signal acquisition and reduce artifacts, and the use of a fabric electrode array for improved contact and comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional disc electrodes are used, then the procedure is simple and compatible with existing EEG methods, but the spatial resolution is low due to blurring effects from varying conductivities in the body
Solution Approach 1:
The electrode is divided into multiple concentric rings (first ring, second ring, third ring) with different diameters and spacings, allowing independent measurement of potential differences at multiple radial positions. This segmentation enables calculation of the surface Laplacian, which enhances spatial resolution by emphasizing local potential changes while reducing the blurring effects of volume conductor conductivities.
Solution Approach 2:
The invention transitions from a single-point disc electrode measurement to a multi-point concentric ring arrangement, adding the radial dimension to the measurement. By measuring potentials at multiple radial distances from the center and calculating the Laplacian, the system achieves enhanced spatial frequency and selectivity without requiring complex external processing.
2Measurement precision
If concentric ring electrodes with multiple rings are used, then spatial selectivity and signal-to-noise ratio are improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The electrode employs nested concentric rings where each ring is positioned within the radial boundary of the outer ring. The first, second, and third rings are arranged concentrically with specific diameter relationships (d1 > d2 > d3) and spacing relationships (s1 = s2), creating a compact nested structure that simplifies manufacturing while maintaining high spatial selectivity through the Laplacian calculation capability.
3Reliability
If electrolyte gels are used to improve electrical contact, then signal quality is improved, but movement artifacts and toxicological concerns arise
Solution Approach 1:
The invention extracts and eliminates the electrolyte gel from the electrode system, achieving reliable electrical contact through the concentric ring geometry and potential difference measurement approach. By measuring the Laplacian through multiple rings, the system maintains good electrical contact and signal quality without requiring electrolyte gels, thereby eliminating movement artifacts and toxicological concerns associated with gel application and removal.
4Measurement precision
If the spacing between rings and disc is reduced to improve spatial frequency, then signal resolution is improved, but electrode offset potentials due to half-cell potentials increase
Solution Approach 1:
The electrode design creates equipotential conditions by measuring potential differences between concentric rings that are equidistant from the center. The spacing between the first ring and second ring (s1) is equal to the spacing between the second ring and third ring (s2), ensuring uniform sampling of the potential field. This equipotential approach minimizes electrode offset potentials from half-cell potentials while maintaining high spatial frequency through the Laplacian calculation.
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 design achieves high-fidelity signal acquisition with reduced artifacts and improved spatial selectivity, allowing for reliable and comfortable bioelectric signal recording without the need for electrolyte gels, while maintaining compatibility with existing EEG methods.
Implementation Method 1
conductive discs and rings... for acquiring bioelectric signals
Data Source
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AI summary
A biomedical electrode is disclosed that includes at least first and second electrical nodes for connection to medical equipment. The biomedical electrode includes a first electrical node including a disc of conductive material having a diameter d1 and a second electrical node including a ring of conductive material. The ring is concentric with the disc and- has a diameter d2 that is larger than d1 and having a ring thickness t2 such that (4 = d1 / t2 = 6). It is further disclosed a biomedical electrode providing at least first, second, third and fourth electrical nodes for connection to medical equipment, said biomedical electrode comprising said first electrical node including a disc of conductive material having a diameter d1; said second electrical node including a first ring of conductive material, said first ring being concentric with the disc and having a radius a that is larger than d1/2; and said third electrical node including a second ring of conductive material, said second ring also being concentric with the disc and having a radius ß that is larger than d2/2; said fourth electrical node including a third ring of conductive material, said third ring also being concentric with the disc and having a radius of thirty millimeters that is larger than d3/2, such that (3 a ß)2 is less than about 0.225 cm4.