Physiological Sensor Contact Detection for Reliable ECG Signals
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Solution Overview
Problem
Existing ECG devices with wet electrodes are invasive and difficult for laypeople to operate, limiting their use to medical settings, while dry electrodes require reliable contact for accurate signal generation but often fail to ensure consistent contact detection.
Innovation Solution
A mobile or wearable device with integrated measurement and reference electrodes uses a stimulation circuit to drive signals, detecting contact through processing circuitry to ensure accurate physiological signal measurement, including contact detection and saturation management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If wet electrodes are used to reduce impedance and improve signal quality, then measurement precision is improved, but device complexity and ease of operation deteriorate due to invasive application requirements
Solution Approach 1:
The patent changes the physical state of the electrode from wet (gel-based) to dry (solid contact), fundamentally altering the interface parameters between electrode and skin. This eliminates the need for gel application while maintaining acceptable impedance levels through optimized dry electrode materials and increased contact surface area, thereby improving ease of operation while preserving measurement precision
2Ease of operation
If dry electrodes are used to simplify operation and reduce invasiveness, then ease of operation is improved, but reliability deteriorates due to inconsistent contact detection
Solution Approach 1:
The patent implements a feedback mechanism where the system continuously monitors the electrical impedance between the dry electrode and the user's skin. When contact is detected (impedance below threshold), the system confirms proper attachment and enables ECG measurement. If contact is insufficient (impedance above threshold), the system provides feedback to the user to improve contact, thereby ensuring reliable and consistent measurements while maintaining ease of operation
Solution Approach 2:
The patent performs preliminary contact verification before initiating ECG measurement. The system checks the electrode-skin interface impedance in advance to confirm proper contact establishment, and only proceeds with measurement when contact criteria are met. This preliminary action ensures reliability is maintained while keeping the overall process simple and user-friendly
3Measurement precision
If multiple electrodes are used to improve ECG waveform quality, then measurement precision is improved, but device complexity increases due to numerous electrodes requiring placement
Solution Approach 1:
The patent designs electrodes that serve multiple functions: they act as both measurement electrodes for ECG signal acquisition and as contact detection sensors for verifying proper attachment. This multi-functionality reduces the need for separate verification electrodes or complex placement procedures, thereby maintaining measurement precision with a simplified electrode configuration that is easier to operate
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
Enables reliable and user-friendly ECG signal acquisition by ensuring consistent electrode contact, improving accuracy and usability for non-medical users.
Implementation Method 1
The stimulation circuit can drive a stimulation signal on one of the measurement electrodes. The processing circuitry can detect a signal resulting from the stimulation signal
Data Source
AI summary
Detecting user contact with one or more electrodes of a physiological signal sensor can be used to ensure physiological signals measured by the physiological signal sensor meet waveform characteristics (e.g., of a clinically accurate physiological signal). In some examples, a mobile and/or wearable device can comprise sensing circuitry, stimulation circuitry, and processing circuitry. The stimulation circuit can drive one or more stimulation signals on one or more electrodes, the resulting signal(s) can be measured (e.g., by the sensing circuitry), and the processing circuitry can determine whether a user is in contact with the electrode(s). Additionally or alternatively, in some examples, mobile and/or wearable device can comprise saturation detection circuitry, and the processing circuitry can determine whether the sensing circuitry is saturated.