Printed Backsheet Liquid Detection for Thinner Hygiene Articles

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional disposable hygiene products with liquid detection features are thick, heavy, uncomfortable, and costly due to complex electrical circuits and conductive elements, leading to pressure points and skin irritations, while also being inefficient in resource utilization.

Innovation Solution

A conductive print on a backsheet film with specific resistance and breathability properties, integrated with a nonwoven layer through a thermolamination process, eliminating the need for additional layers and ensuring a thin, flexible, and comfortable design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If complex electrical circuits and conductive elements are used for liquid detection, then liquid detection functionality is achieved, but the product becomes thick, heavy, and uncomfortable

Engineering Contradiction:
Improveliquid detection functionalityVSAvoidproduct weight and thickness
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent extracts the liquid detection functionality from complex electrical circuits and implements it through a simple conductive trace pattern printed directly on the backsheet film. This eliminates the need for separate sensor modules, capacitive electrodes, and associated electronics, thereby reducing weight and thickness while maintaining detection capability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses a printed conductive trace that copies the functionality of traditional conductive elements but in a simplified form. The conductive ink pattern replicates the electrical pathway function without requiring thick conductive layers or multiple bonding layers, achieving the same detection purpose with minimal added mass

Inventive Principle:
Principle #26Copying

2Reliability

If complex electrical circuits and conductive elements are used for liquid detection, then liquid detection functionality is achieved, but manufacturing complexity and costs increase

Engineering Contradiction:
Improveliquid detection functionalityVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the conductive trace layer with the backsheet film by printing the conductive ink directly onto the film surface. This integration eliminates separate application steps for conducting elements and reduces the number of layers that need to be bonded together, simplifying manufacturing while maintaining detection functionality

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the form factor of conductive elements from thick, multi-layer constructed components to thin printed ink patterns. This parameter change in the physical state and application method of conductive materials reduces manufacturing complexity and enables more efficient production processes

Inventive Principle:
Principle #35Parameter changes

3Reliability

If additional layers are added for liquid detection, then detection capability is improved, but comfort and tactile properties deteriorate

Engineering Contradiction:
Improveliquid detection capabilityVSAvoidpressure points and skin irritations
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies conductive properties locally through printed trace patterns only where needed for detection, rather than using universal conductive layers throughout the product. This localized approach maintains detection capability while minimizing the presence of conductive materials that could cause discomfort, allowing other areas to maintain soft, comfortable properties

Inventive Principle:
Principle #3Local quality

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 solution provides reliable liquid detection with improved comfort and tactile feel, maintaining mechanical integrity and reducing manufacturing complexity and costs, thus enhancing the quality of disposable hygiene products.

Implementation Method 1

A conductive print on a backsheet film with specific resistance and breathability properties

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Implementation Method 2

integrated with a nonwoven layer through a thermolamination process

Methodology Applied
Scientific EffectThermal bonding: Heating

Data Source

PatentEP4149402B1Arrangement for detecting liquid
Publication Date: 2026.02.04 RKW SE
  • EP4149402B1 patent drawingFigure 1~2
  • EP4149402B1 patent drawingFigure 3~4

AI summary

The invention relates to an arrangement (4) for detecting liquid in a single-use hygiene article. The arrangement (4) comprises a back sheet film (1) with a conductive print (2).