Capacitive Diaper Strip Sensor With Shielded Impedance Sensing

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing incontinence monitoring systems for absorbent hygiene articles suffer from inaccurate sensing, false positives/negatives, require direct contact with excretion, necessitate special absorbent articles, cause skin irritations, and are costly and unsustainable.

Innovation Solution

A strip element with capacitive sensing elements and shielding components that measure impedance changes without direct contact, allowing attachment to the garment-facing surface of absorbent articles, reducing false readings and environmental impact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a sensor is placed close to the skin for detection, then detection sensitivity is improved, but skin irritations and pressure marks occur

Engineering Contradiction:
Improvedetection sensitivityVSAvoidskin irritations
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an absorbent article as an intermediary layer between the sensor and the skin. The sensor is positioned on the outer surface of the absorbent article rather than directly on the skin, allowing detection of incontinence events through the article while eliminating direct skin contact that causes irritation and pressure marks.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If direct contact sensing is used for detection, then detection accuracy is improved, but hygiene issues and cleaning requirements increase

Engineering Contradiction:
Improvedetection accuracyVSAvoidhygiene issues
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The absorbent article serves as a mediator that allows the sensor to detect incontinence events without direct contact with excretions. The sensor detects changes in the absorbent article (such as weight, moisture, or electrical properties) that indicate incontinence, maintaining detection accuracy while preventing contamination and reducing cleaning requirements.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If a cavity is created in the absorbent article for sensor placement, then sensor accommodation is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvesensor accommodationVSAvoidmanufacturing complexity
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

Instead of creating a fixed cavity in the absorbent article, the patent uses a dynamic approach where the sensor is positioned on the outer surface and detects changes as the article deforms or moves during use. This eliminates the need for precise cavity formation while maintaining sensor functionality.

Inventive Principle:
Principle #15Dynamics

4Reliability

If specialized absorbent articles are designed for sensor integration, then sensor functionality is improved, but device complexity and cost increase

Engineering Contradiction:
Improvesensor functionalityVSAvoidarticle customization
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent designs the sensor system to work with standard, commercially available absorbent articles rather than requiring specially customized articles. The sensor can detect incontinence events in various types of absorbent articles (diapers, incontinence pants, etc.), making the system universal and reducing complexity associated with custom article design and manufacturing.

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

Enhances measurement accuracy, reduces false positives/negatives, eliminates the need for regular cleaning/replacement, and lowers operational costs while promoting comfort and sustainability.

Implementation Method 1

The strip element comprises at least a first sensing element for measuring an impedance, the first sensing element having a capacitor electrode

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

The first sensing element further comprises a shielding component provided between the signal line and the ground element

Methodology Applied
Scientific EffectElectromagnetic shielding: Faraday Cage

Data Source

PatentEP4171464B1Strip element for an absorbent hygiene article
Publication Date: 2025.12.17 ESSITY HYGIENE & HEALTH AB
  • EP4171464B1 patent drawingFigure 1a~2c
  • EP4171464B1 patent drawingFigure 3~4
  • EP4171464B1 patent drawingFigure 5a~5c

AI summary

The present disclosure relates to a strip element configured to be internally or externally, fixedly or removably provided to an absorbent hygiene article, such as a diaper. The strip element comprises at least one sensing element for obtaining excretion-related information in a hygiene article such as a diaper, the sensing element having a capacitor electrode, a signal line, and a ground element such as a ground electrode and/or ground line. The capacitor electrode and the ground element are for measuring an impedance. The capacitor electrode is electrically connected to the signal line. The sensing element further comprises a shielding component provided between the signal line and the ground element. The strip element is configured such that an electric potential of the shielding component synchronously oscillates with an electric potential of the signal line.