Infrared Wetness Detection for Absorbent Articles

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Solution Overview

Problem

Conductive elements in absorbent articles, such as diapers, cause manufacturing challenges and security issues due to metal detection interference, and existing wetness indicators are costly and invasive.

Innovation Solution

A non-invasive infrared reflectance sensing system using a paired IR generator/detector system attached to the outer cover of absorbent articles to detect urine presence without conductive elements, emitting signals when urine is absorbed, altering the infrared reflectance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conductive elements are incorporated into absorbent articles to detect wetness, then wetness detection capability is improved, but manufacturing complexity and security issues worsen

Engineering Contradiction:
Improvewetness detection capabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent removes conductive elements from the absorbent article structure and replaces them with an external optical sensing system. The IR generator and detector are positioned outside the article, eliminating the need to embed conductive threads or foils during manufacturing, thus resolving the manufacturing complexity issue while maintaining wetness detection capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the electrical/conductive-based wetness detection system with an optical system using infrared radiation. Instead of using conductive elements that require electrical circuits, the system uses IR light interaction with urine to detect wetness, eliminating security concerns about metal detectors while achieving the same measurement function.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If conductive leads are made from metal to improve conductivity, then electrical conduction is improved, but security detection interference worsens

Engineering Contradiction:
Improveelectrical conductionVSAvoidsecurity detection interference
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent completely replaces the electrical conduction-based detection system with an optical system using infrared radiation. This substitution eliminates all metal and conductive materials from the detection mechanism, resolving the security detection interference issue while maintaining reliable wetness detection through optical means.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If passive wetness indicators are included in each absorbent article, then wetness indication is improved, but product cost worsens

Engineering Contradiction:
Improvewetness indicationVSAvoidproduct cost
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent employs a single external IR generator/detector system that can service multiple absorbent articles simultaneously. Rather than embedding individual detection systems in each article, the external device can scan or monitor multiple articles, reducing the per-unit cost while maintaining wetness indication capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent uses optical reflection principles where the IR detector measures the reflection of IR light from the article surface. This indirect measurement method allows for cost-effective detection without requiring expensive embedded sensors in each article, achieving wetness indication through a simpler, cheaper optical reflection measurement.

Inventive Principle:
Principle #26Copying

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

Enables cost-effective, non-invasive wetness detection in absorbent articles without altering manufacturing processes, providing quick response times and compliance with security standards, capable of detecting small urine amounts and multiple insults.

Implementation Method 1

The sensor includes a paired IR generator/detector system. The present invention also provides a urine collection and detection system accordance with claim 14. The paired IR generator/detector includes an infrared-generating light-emitting diode

Methodology Applied
Scientific EffectLight-emitting diode: Light Emitting Diode

Implementation Method 2

an infrared-detecting phototransistor. The paired IR generator/detector adapted to sense a change in infrared light reflectance

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Implementation Method 3

The sensor is placed in communication with a signaling device. Once a change within the interior of an absorbent article is detected, the signaling device can be configured to emit a signal that indicates urine is present in the absorbent article. Insulting the absorbent article with urine will create a change in infrared reflectance as some of the infrared is absorbed by the insult.

Methodology Applied
Scientific EffectInfrared absorption: Absorption (EM radiation)

Data Source

PatentEP2512392B1Infrared wetness detection system for an absorbent article
Publication Date: 2020.01.08 KIMBERLY CLARK WORLDWIDE INC
  • EP2512392B1 patent drawingFigure 1
  • EP2512392B1 patent drawingFigure 2
  • EP2512392B1 patent drawingFigure 3

AI summary

A signaling device for sensing and indicating the presence of a body exudate in an absorbent article includes a housing and a paired IR generator/detector disposed within the housing, the paired IR generator/detector adapted to sense a change in infrared light reflectance due to an insult to the absorbent article, the paired IR generator/detector including an infrared-generating light-emitling diode and an infrared-detecting phototransistor. In addition, a body exudate collection and detection system includes an absorbent article and a signaling device adapted to be used in conjunction with the absorbent article for detecting the presence of a body exudate therein, the signaling device including a housing and a paired IR generator/detector disposed within the housing, the paired IR generator/detector including an infrared-generating Sight-emitting diode and an infrared-detecting phototransistor.