Stacked Bioelectrode Pad for Motion Noise Reduction

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Solution Overview

Problem

Conventional electrocardiograph bioelectrode pads struggle to obtain sufficient body motion noise signals due to size limitations, making it difficult to effectively eliminate body motion noise from electrocardiac signals.

Innovation Solution

The bioelectrode pad design involves stacking multiple electrodes in a thickness direction with conductive gel sheets in between, allowing for series connection and enabling detection of both body motion noise and electrocardiac signals with sufficient levels, with the outer electrode used for body motion noise detection and the inner electrode for electrocardiac signal detection, and vice versa, allowing for adjustable gain settings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the electrode area is reduced to fit within practical size limitations of the bioelectrode pad, then the pad size is reduced, but the body motion noise signal level becomes insufficient

Engineering Contradiction:
Improvebioelectrode pad sizeVSAvoidbody motion noise signal level
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The patent transitions from a planar electrode arrangement to a three-dimensional stacked configuration. Multiple electrodes are arranged in the thickness direction (vertical dimension) rather than spreading out in the horizontal plane. This dimensional change allows the electrodes to maintain a small footprint on the skin while achieving sufficient signal levels through the stacked series connection of multiple electrodes.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent implements a nested structure where multiple electrodes are stacked one above another in the thickness direction, with conductive gel sheets interposed between them. This nesting arrangement allows the electrodes to be contained within a compact volume, achieving sufficient signal levels without increasing the overall pad area.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Measurement precision

If multiple electrodes are stacked in the thickness direction with conductive gel sheets, then both body motion noise signal and electrocardiac signal levels become sufficient, but the device structure becomes more complex

Engineering Contradiction:
Improvesignal detection levelVSAvoidelectrode stacking structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the single electrode function into multiple segmented electrodes stacked in series. Each electrode in the stack contributes to the overall signal detection, and the segmentation allows for separate detection of body motion noise and electrocardiac signals through appropriate electrode combinations, thereby improving signal levels without requiring a single large electrode.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The stacked electrode configuration serves multiple functions simultaneously: it detects both body motion noise signals and electrocardiac signals with sufficient levels, provides series connection for signal amplification, and maintains a compact pad size. The same electrode stack structure enables versatile signal acquisition without requiring separate dedicated structures for each function.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 allows for effective detection and removal of body motion noise from electrocardiac signals, improving signal quality by enabling sufficient level detection and easy gain settings of both signals.

Implementation Method 1

stacking a plurality of electrodes in a thickness direction via the conductive gel sheet therebetween

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP2774535B1Bioelectrode pad for electrocardiograph
Publication Date: 2023.02.15 NIPRO CORP
  • EP2774535B1 patent drawingFigure 1(a)~1(b)
  • EP2774535B1 patent drawingFigure 2~3(b)
  • EP2774535B1 patent drawingFigure 4(a)~5

AI summary

[Problem] To provide an electrocardiograph capable of stably measuring an electrocardiac signal without being disturbed by body motion noise. [Solution] An electrocardiograph measures an electrocardiac signal by processing electric signals detected by using a plurality of bioelectrode pads attached to the skin of a living body and is characterized as follows. The bioelectrode pads each comprises: a plurality of sheets of electrodes disposed by being stacked on each other; conductive gel sheets disposed alternately with the sheets of electrodes and interposed between the electrodes; and a dynamic pressure stabilizing plate disposed by being stacked in a stacked direction of the sheets of electrodes, on the side opposite to the side of the skin, outside the sheets of electrodes. The electrocardiograph comprises: a first differential circuit for obtaining an electrocardiac source signal by taking the difference between signals each obtained from any one of the electrodes of each of two bioelectrode pads among the plurality of bioelectrode pads; a second differential circuit for obtaining a body motion noise signal by taking the difference between signals obtained from any two of the electrodes of each of said two bioelectrode pads; and a body motion noise removing circuit for removing the low frequency components of the body motion noise signal of each of said two bioelectrode pads from the electrocardiac source signal.