Moisture Detection in Absorbent Articles Using Multi-Frequency Capacitive Sensing
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Solution Overview
Problem
Users of disposable absorbent articles, such as diapers, often remain in contact with bodily exudates for extended periods due to the lack of effective moisture detection and estimation systems, leading to potential health issues.
Innovation Solution
A method for moisture detection and estimation in absorbent articles using multiple frequencies, where a drive signal of multiple frequencies is applied to a drive electrode, and sense signals are sensed from a sense electrode to detect the first wetness event and saturation of the absorbent article.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If single frequency moisture detection is used, then device complexity is reduced, but measurement precision and reliability of moisture detection deteriorate
Solution Approach 1:
The patent applies parameter changes by using multiple drive signal frequencies (e.g., first frequency for initial wetness detection, second frequency for saturation detection) to improve measurement precision. Different frequencies provide different penetration depths and sensitivity characteristics, enabling more accurate moisture assessment at various absorption stages without requiring complex additional hardware
2Measurement precision
If multiple frequencies are used for moisture detection, then measurement precision improves, but use of energy increases
Solution Approach 1:
The system implements periodic action by alternately applying drive signals at different frequencies rather than continuously using all frequencies simultaneously. The controller selectively activates specific frequencies based on detection needs (e.g., using first frequency for initial wetness, switching to second frequency for saturation detection), reducing overall energy consumption while maintaining high measurement precision when needed
3Object-affected harmful factors
If no moisture detection system is used, then device complexity is minimized, but health risks from prolonged contact with bodily exudates increase
Solution Approach 1:
The patent replaces complex mechanical or chemical moisture detection systems with electrical impedance measurement using capacitive coupling. The detection electrodes measure changes in electrical properties of the absorbent core material as it absorbs moisture, providing reliable health safety monitoring through simple electrical measurements rather than complex mechanical sensors or chemical indicators
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 solution enables the detection of the first wetness event and the estimation of saturation in absorbent articles, preventing prolonged contact with bodily exudates and reducing health risks.
Implementation Method 1
applying, by capacitive coupling, drive signal of multiple frequencies to a drive electrode in the absorbent article
Implementation Method 2
sensing, by capacitive coupling, sense signal of the multiple frequencies from a sense electrode in the absorbent article
Data Source
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AI summary
A method of moisture detection and estimation in an absorbent article with use of multiple frequencies is provide that comprises: applying, by capacitive coupling, drive signal of multiple frequencies to a drive electrode in the absorbent article; sensing, by capacitive coupling, sense signal of the multiple frequencies from a sense electrode in the absorbent article; detecting the first wetness event in the absorbent article with use of sense signal of a frequency of the multiple frequencies; and detecting the saturation of the absorbent article with use of sense signal of another frequency of the multiple frequencies.