Absorbent Article Wetness Detector with Segmented Conductive Lines
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Solution Overview
Problem
Existing absorbent articles with wetness detectors suffer from false detections due to short circuits between conductive leads and the absorbent core, and lack the ability to accurately discern the longitudinal extent of liquid discharge, making them inefficient and prone to manufacturing complexities.
Innovation Solution
The design incorporates a laminate structure with electrically insulating layers and conductive lines, where exposed portions form electrodes in contact with the absorbent core, while covered portions act as insulated leads, allowing for longitudinal detection zones without false positives and maintaining manufacturing simplicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If leads are in electrical communication with the absorbent core to enable detection, then wetness detection capability is provided, but false detections occur due to short circuits between leads and the reference electrode
Solution Approach 1:
An electrically insulating layer is introduced as an intermediary between the conductive leads and the absorbent core. This layer prevents direct electrical contact that causes short circuits and false detections, while still allowing the detection system to function through controlled electrical pathways.
Solution Approach 2:
The conductive lines are segmented into distinct functional portions: exposed portions that form electrodes for detection and covered portions that form insulated leads. This segmentation separates the detection function from the connection function, preventing interference between them.
2Reliability
If conductive paths are arranged laterally separated to avoid short circuits, then false detections are reduced, but the ability to detect longitudinal extent of liquid discharge is lost
Solution Approach 1:
The detection capability is extended to the longitudinal dimension by arranging multiple detection zones along the longitudinal axis of the absorbent article. Each zone is defined by pairs of electrodes at different longitudinal positions, enabling determination of liquid discharge extent in the longitudinal direction.
3Ease of manufacture
If a simple parallel conductive path structure is used, then manufacturing is simplified, but longitudinal wetting discrimination capability is lost
Solution Approach 1:
The conductive lines are segmented into distinct functional portions: exposed portions that form electrodes for detection and covered portions that form insulated leads. This segmentation separates the detection function from the connection function, preventing interference between them.
4Measurement precision
If conductive lines are fully exposed to the absorbent core, then detection sensitivity is maximized, but short circuits between leads and core occur
Solution Approach 1:
The conductive lines are segmented into distinct functional portions: exposed portions that form electrodes for detection and covered portions that form insulated leads. This segmentation separates the detection function from the connection function, preventing interference between them.
Solution Approach 2:
Different portions of the conductive lines have different electrical properties: exposed portions are electrically active for detection while covered portions are electrically isolated for safe connection. This local differentiation of electrical properties enables both sensitive detection and reliable isolation.
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 solution effectively reduces false detections and accurately determines the longitudinal extent of liquid discharge, enhancing the reliability and ease of manufacturing of absorbent articles by preventing conductive bridges between leads through the wet absorbent core.
Implementation Method 1
the wet absorbent core produces a conductive bridge between the electrodes
Implementation Method 2
the absorbent core changes from a dry state to a wet state
Data Source
Figure 1a~1b
Figure 1c~1d
Figure 2a~2b
AI summary
An absorbent article that has a back sheet with an absorbent core disposed on a body side of the back sheet. On a back side of the back sheet, there is provided a substrate carrying a conductive pattern as a liquid discharge detection circuit that is able to be connected to an electric potential generator for performing liquid discharge detection. At least one or a plurality of holes is formed through the back sheet to communicate portions of the conductive pattern with the absorbent core. Longitudinally adjacent pairs of the revealed portions of the conductive pattern form liquid discharge detection zones for detecting liquid discharge in the absorbent core. The detection zones are longitudinally distributed with respect to the absorbent core.