Segmented Shielding Elements for EMI Protection in Physiological Measurement Electrodes
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Solution Overview
Problem
Electrodes and signal lines in measurement circuitry are susceptible to electromagnetic interference (EMI), which corrupts measurement signals and degrades accuracy in physiological measurements such as electrocardiograms and bioimpedance signals.
Innovation Solution
The implementation of a second layer with electrically conductive shielding elements that are arranged to cover measurement electrodes and extend adjacent to each other, providing equal EMI absorption characteristics and eliminating differential interference components, while being isolated from each other to prevent skin contact variations from causing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single protective electrode structure is used, then some EMI protection is provided, but differential EMI components cannot be effectively eliminated
Solution Approach 1:
The protective electrode structure is segmented into multiple separate shielding elements (first shielding element, second shielding element, etc.) that are electrically isolated from each other. Each shielding element is connected to a different skin electrode, allowing independent EMI absorption paths that eliminate differential interference components while maintaining overall protection reliability.
2Object-affected harmful factors
If shielding elements are electrically connected, then EMI protection is provided, but skin contact variations cause differential interference
Solution Approach 1:
The shielding elements are electrically segmented and isolated from each other, with each element connected to a separate skin electrode. This segmentation prevents skin contact variations from creating differential interference between shielding elements, as each element independently absorbs EMI without electrical interaction that would amplify contact variations.
Solution Approach 2:
Each shielding element is connected to its respective skin electrode to establish equipotential conditions, reducing the effect of skin contact variations. By maintaining equipotential connections individually for each shielding element rather than connecting them together, the system achieves EMI protection without differential interference from contact inconsistencies.
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 effectively reduces or eliminates differential EMI components, allowing common mode filtering to eliminate residual interference, thereby enhancing the accuracy of measurement signals by ensuring both shielding elements absorb EMI in a similar manner.
Implementation Method 1
a second layer comprising: a first shielding element which is electrically conductive and arranged to cover at least partially both the first measurement electrode and second measurement electrode so as to protect the first measurement electrode and second measurement electrode against the EMI
Data Source
Figure 1~2B
Figure 2C~3B
Figure 3C~4B
AI summary
The present document discloses an apparatus comprising: a first layer comprising at least a first measurement electrode (102) and a second measurement electrode (104) disposed at a distance from one another, wherein the first measurement electrode and second measurement electrode are skin electrodes configured to measure an electric physiological property from a skin; a second layer disposed on top of the first layer and comprising: a first and a second shielding element (200, 202) that are electrically conductive and arranged to cover at least partially both the first measurement electrode and second measurement electrode so as to protect the first measurement electrode and second measurement electrode against electromagnetic interference, wherein each of the shielding elements are connected to a skin electrode (102, 104, 220, 222), wherein the first shielding element and the second shielding element extend adjacent with respect to one another between the first measurement electrode and the second measurement electrode on a plane defined by the second layer, and wherein the second shielding element is electrically isolated from the first shielding element.