Parallel Planar Capacitors for Reusable Absorbent Filling Sensing

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Solution Overview

Problem

Existing sensor arrangements for absorbent articles face reliability issues when decoupled from the absorbent article, offering little sensitivity and reliability due to external conditions and patient movement, while integrated sensors require disposal with the article.

Innovation Solution

A sensor arrangement with a flexible substrate and planar capacitors connected in parallel, attached to the absorbent article's surface, uses conductor paths to connect capacitor electrodes to a readout circuit, allowing reliable detection of voiding events and absorption levels through capacitive changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the sensor arrangement is integrated and hard-wired with the absorbent article, then the measurement reliability is improved, but the sensor arrangement must be disposed of once the absorbent article is full

Engineering Contradiction:

Improvemeasurement reliabilityVSAvoidsensor reuse duration

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

The system is divided into two separate components: a disposable absorbent article and a reusable sensor arrangement. The sensor arrangement can be detached and reused with multiple absorbent articles, resolving the contradiction between measurement reliability and sensor reuse duration.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A flexible substrate with planar capacitors serves as an intermediary between the absorbent article and the readout circuit. This flexible interface allows the sensor to maintain reliable measurements while being adaptable to different absorbent articles, enabling both reliability and reuse.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Duration of action of moving object

If external sensor arrangements are used, then the sensor can be reused, but the sensitivity and reliability are reduced due to external conditions and patient movement

Engineering Contradiction:

Improvesensor reuse durationVSAvoidmeasurement reliability

Core Design Contradiction:

Duration of action of moving objectVSReliability

Solution Approach 1:

The mechanical contact-based sensing is replaced with a capacitive sensing system. The planar capacitors detect changes in electrical field caused by fluid absorption, eliminating the need for direct mechanical contact with the absorbent article. This substitution maintains high sensitivity and reliability while enabling sensor reuse.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

A flexible substrate is used to mount the planar capacitors, allowing the sensor arrangement to conform to the surface of the absorbent article without requiring rigid mechanical contact. This flexibility maintains measurement reliability while enabling easy attachment and detachment for reuse.

Inventive Principle:

Principle #30Flexible shells and thin films

3Measurement precision

If multiple planar capacitors are connected in parallel, then the sensitivity and reliability of detecting voiding events is enhanced, but the device complexity increases

Engineering Contradiction:

Improvedetection sensitivityVSAvoidsensor arrangement complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

Multiple planar capacitors are connected in parallel to combine their sensing capabilities. This merging of multiple sensing elements enhances the overall sensitivity and reliability of voiding event detection while maintaining a relatively simple circuit configuration.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The parallel capacitor configuration serves multiple functions: it enhances detection sensitivity, provides redundancy for improved reliability, and maintains compatibility with the existing readout circuit. This multi-functionality achieves high measurement precision without proportionally increasing device complexity.

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

The parallel connection of capacitors enhances the sensitivity and reliability of detecting voiding events, enabling accurate monitoring and reuse of the sensor arrangement without damaging the absorbent article.

Implementation Method 1

a plurality of planar capacitors, each one including a set of at least two corresponding capacitor electrodes being arranged next to each other on or in the substrate

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

a sensor arrangement for sensing a filling state of an absorbent article with a liquid absorbent layer

Methodology Applied

Scientific EffectDielectric: Dielectric

Data Source

PatentUS20260049956A1Sensor arrangement for sensing a filling state of an absorbent article

Publication Date: 2026.02.19 ESSITY HYGIENE & HEALTH AB

AI summary

A sensor arrangement for sensing a filling state of an absorbent article with a liquid absorbent layer, the sensor arrangement comprising a substrate, a plurality of planar capacitors, each one comprising a set of at least two corresponding capacitor electrodes being arranged next to each other on or in the substrate, and a plurality of conductor paths on or in the substrate connecting the capacitor electrodes toward terminals of a readout circuit, wherein at least two of said planar capacitors are connected in parallel.