Liquid Discharge Detection in Absorbent Articles

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Solution Overview

Problem

Conventional methods for detecting liquid discharge in absorbent articles are prone to false positives due to factors like loose wiring, pressure changes, and sweat saturation, and struggle to accurately detect multiple micturitions, leading to unreliable detection and potential non-detection of small liquid amounts.

Innovation Solution

A method that analyzes liquid discharge data over time in relation to reference data using techniques such as curve fitting, correlation, and convolution to determine the degree of conformity or correlation, allowing for more reliable detection of liquid discharge events by considering variations and non-linear relationships, rather than relying on a single threshold value.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single threshold value is used for detection, then the device complexity is low, but the measurement precision deteriorates due to false positives

Engineering Contradiction:
Improvedetection method complexityVSAvoidliquid discharge detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The system performs preliminary actions by continuously monitoring resistance values over time and establishing baseline patterns before actual detection is needed. This allows the system to prepare reference data and detection algorithms in advance, improving detection accuracy without adding complex hardware.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Instead of single-point threshold comparison, the system implements continuous monitoring of resistance values over time. This continuous action allows the system to track changes dynamically and distinguish true liquid discharge events from transient noise or false positives.

Inventive Principle:
Principle #20Continuity of useful action

2Reliability

If a higher threshold value is chosen, then false positive detections are reduced, but the measurement precision deteriorates due to non-detection of small liquid amounts

Engineering Contradiction:
Improvefalse positive reductionVSAvoidsmall liquid amount detection
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The system transitions from static threshold comparison to dynamic threshold adjustment based on continuously monitored resistance patterns. The detection threshold adapts over time based on learned baseline behavior, allowing the system to maintain high reliability while detecting small liquid amounts that would be missed by fixed thresholds.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system implements feedback by continuously monitoring resistance values and using this information to adjust detection parameters. The detection algorithm learns from past measurements and adjusts its sensitivity dynamically, ensuring both false positive reduction and small amount detection capability.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If resistance monitoring is performed over time, then the measurement precision improves for detecting multiple micturitions, but the loss of time increases due to continuous monitoring

Engineering Contradiction:
Improvemultiple liquid discharge detectionVSAvoidcontinuous monitoring duration
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system implements periodic sampling of resistance values rather than truly continuous monitoring. By sampling at optimized intervals and using pattern recognition algorithms, the system achieves high detection precision for multiple liquid discharge events while minimizing the time resource consumption associated with constant monitoring.

Inventive Principle:
Principle #19Periodic action

4Duration of action of stationary object

If the absorbent article is worn for an extended period, then the reliability of detecting subsequent liquid discharge deteriorates due to sweat saturation

Engineering Contradiction:
Improvewear durationVSAvoidsubsequent liquid discharge detection
Core Design Contradiction:
Duration of action of stationary objectVSReliability

Solution Approach 1:

The system performs preliminary characterization of the resistance baseline during the initial wear period before sweat saturation occurs. By establishing reference patterns early in the wear cycle, the system can later distinguish between resistance changes caused by sweat and those caused by actual liquid discharge, maintaining reliability throughout extended wear.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously updates its understanding of the baseline resistance pattern based on feedback from ongoing monitoring. This adaptive approach allows the system to account for gradual changes in the absorbent article properties over time, including sweat saturation effects, while maintaining accurate detection of new liquid discharge events.

Inventive Principle:
Principle #23Feedback

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 approach significantly reduces false positive detections, improves the accuracy of liquid discharge detection, and allows for reliable detection of multiple events, reducing the impact of noise and sensor errors, such as short circuits.

Implementation Method 1

a sensor monitors a resistance between two conductors arranged in a diaper

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Data Source

PatentEP2793782B1Method for detecting a liquid discharge to an absorbent article
Publication Date: 2021.01.20 ESSITY HYGIENE & HEALTH AB
  • EP2793782B1 patent drawingFigure 1
  • EP2793782B1 patent drawingFigure 2
  • EP2793782B1 patent drawingFigure 3

AI summary

A method for detecting a liquid discharge event in an absorbent article including a sensor adapted to generate an electrical output signal representative of a degree of wetness of the absorbent article, wherein the electrical output signal is received by a processing unit. The method including the steps of providing reference data over time representative of a liquid discharge; acquiring liquid discharge data over time in form of the electrical output signal; analyzing the liquid discharge data over time in relation to the reference data over time by the processing unit; and detecting a liquid discharge event based on the analysis. Also disclosed is a system for detecting liquid discharge event in an absorbent article including an absorbent article including a sensor being arranged to generate an output signal representative of an electrical property, and a processing unit adapted to process the output signal generated by the sensor of the absorbent article.