Smart Absorbent Articles Using Capacitive Exudate Detection
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Solution Overview
Problem
Existing absorbent articles for personal hygiene face challenges in accurately monitoring liquid and stool exudates in a cost-effective manner with minimal risk of false positives, while also requiring complex and costly sensor systems that are not suitable for disposable use.
Innovation Solution
The absorbent article incorporates a first indicator with electrically conductive material and capacitive coupling to a reusable second indicator, allowing for automated exudate detection through capacitive coupling and resistive sensing, eliminating the need for galvanic connections and reducing production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex sensor systems with signal processing units and batteries are used to monitor exudates, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the sensing function from complex electronic sensors and implements it through simple capacitive coupling between conductive indicators. The first indicator with conductive material and capacitive coupling to a reusable second indicator eliminates the need for signal processing units, transmitters, and batteries, achieving exudate detection through basic electrical principles rather than complex sensor systems
Solution Approach 2:
The first indicator is designed as a disposable component integrated into the absorbent article, eliminating the need for expensive reusable sensors. This approach allows the sensing function to be discarded with the article after use, avoiding the complexity and cost of making expensive sensors reusable while maintaining detection functionality
2Loss of substance
If reusable sensors are used to reduce cost, then loss of substance is improved, but reliability deteriorates due to moisture exposure
Solution Approach 1:
The sensing system is segmented into two distinct parts: a disposable first indicator with conductive material that contacts exudates, and a reusable second indicator with sensing circuitry that remains protected. This segmentation allows the reusable component to avoid moisture exposure while the disposable component absorbs it, maintaining both reliability and resource efficiency
3Measurement precision
If galvanic connections are used for sensing, then measurement precision is improved, but ease of manufacture worsens due to production complexity
Solution Approach 1:
The patent replaces galvanic connections with capacitive coupling for the sensing mechanism. This substitution eliminates the need for direct electrical contact between components, simplifying manufacturing by removing requirements for precise electrical connections while maintaining sensing accuracy through electrical field interaction across an insulating barrier
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 enables accurate and reliable detection of exudates with reduced material and power consumption, minimizing false positives and maintaining article flexibility and cost-effectiveness.
Implementation Method 1
the first indicator comprises an electrically conductive material, wherein the first indicator comprises one or more first input capacitors, one or more first output capacitors and a plurality of conductive tracks forming an electrical connection between the input and output capacitors
Implementation Method 2
allowing for automated exudate detection through capacitive coupling and resistive sensing
Implementation Method 3
the backsheet is breathable and has a water vapour transmission rate (WVTR) of at least 3000g/(m2 x 24h)
Data Source
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AI summary
An absorbent article for personal hygiene comprising: a topsheet; a backsheet, wherein the topsheet is liquid permeable and the backsheet is substantially liquid impermeable; an absorbent core positioned between said topsheet and backsheet; a first indicator for indicating the presence of exudates and being positioned on a garment-facing side of said backsheet such that said first indicator is sandwiched between said backsheet and an outer cover of said article; or wherein said first indicator is positioned on a body-facing side of said backsheet such that said backsheet and an outer cover are able to come into contact with one another; and wherein said first indicator comprises an electrically conductive material, wherein the first indicator comprises one or more first input capacitors, one or more first output capacitors and a plurality of conductive tracks forming an electrical connection between the input and output capacitors, preferably such that each first output capacitor is in galvanic contact with each said first input capacitor. Wherein a reusable or single-use second indicator is arranged to be capacitively coupled with at least the first input and output capacitors such that upon a voiding event an amount of exudate may be automatically determined by measuring a dissipation factor or attenuation of an input signal such as a voltage, said second indicator comprising one or more second input capacitors, one or more second output capacitors and a sensing circuitry, and wherein the backsheet is breathable and has a water vapour transmission rate (WVTR) of at least 3000g/(m2.24h), according to ASTM E96 A (Desiccant method); and/or wherein the outer cover (OC) is a nonwoven comprising synthetic fibers.