Conductive Open Loop Sensor for Liquid Discharge Location

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Solution Overview

Problem

Existing absorbent articles with liquid discharge sensors lack the ability to accurately determine the location and extent of liquid spread within the absorbent core, and there is no reliable method to verify the functionality of these sensors without external alarms or complex hydration analysis systems.

Innovation Solution

Incorporating a conductive open loop with terminal ends connected to an electric potential generator, where liquid discharge causes a short circuit, allowing impedance measurement to determine the location and extent of liquid spread relative to the terminal ends, and using multiple loops for enhanced accuracy and detection of liquid discharge leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a simple conductive strip sensor is used to detect liquid discharge, then the sensor can indicate when liquid discharge has occurred, but it cannot determine the location or extent of liquid spread

Engineering Contradiction:
Improveliquid discharge location determinationVSAvoidsensor structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The conductive strip is segmented into multiple discrete conductive elements arranged in a grid pattern across the absorbent article. Each conductive element can be independently addressed, allowing the system to determine which specific elements are wetted by liquid discharge, thereby providing location information while maintaining a relatively simple overall sensor structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sensor transitions from a one-dimensional conductive strip to a two-dimensional grid array of conductive elements. This dimensional expansion enables the sensor to provide spatial information about liquid discharge location and extent across the absorbent article surface, not just a binary wet/dry state.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If conductive strips are positioned to detect liquid discharge, then liquid discharge events can be detected, but there is no means to verify sensor functionality or detect breaks in the conductive strip

Engineering Contradiction:
Improvesensor functionality verificationVSAvoidsensor configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The sensor system performs preliminary self-diagnosis by continuously monitoring the electrical continuity of each conductive element and its connections to the control circuitry. This preliminary action detects breaks or failures in the conductive elements before they affect liquid discharge detection, ensuring reliable operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The control circuitry receives feedback signals from each conductive element indicating its electrical state. This feedback mechanism allows the system to verify sensor functionality, detect breaks in conductive elements, and distinguish between sensor failures and actual liquid discharge events, thereby improving reliability.

Inventive Principle:
Principle #23Feedback

3Loss of information

If multiple conductive elements are used to determine liquid spread extent, then absorbency performance can be analyzed, but the sensor requires more complex processing to interpret the data

Engineering Contradiction:
Improveliquid discharge spread informationVSAvoiddata processing requirements
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The control circuitry extracts only the essential information from the sensor data - specifically, identifying which conductive elements are wetted and calculating the extent of liquid spread based on the pattern of wetted elements. This extraction approach provides sufficient absorbency performance information without requiring complex processing of all sensor data.

Inventive Principle:
Principle #2Taking out (Extraction)

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 precise determination of liquid discharge location and extent within the absorbent core, verifies sensor functionality, and provides detailed data on absorbency performance and liquid volume, improving the overall effectiveness of absorbent articles.

Implementation Method 1

a conductive open loop having terminal ends for electrical communication with opposing poles of an electric potential generator such that liquid discharge in the space defined within the open loop is able to cause a short circuit in the open loop

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

the impedance change is measureable to determine a location relative to the terminal ends where the liquid discharge has caused the short circuit

Methodology Applied
Scientific EffectElectrical impedance change: Electrical Resistance

Data Source

PatentEP2654646B1Absorbent article comprising a liquid discharge sensor
Publication Date: 2016.07.27 SCA HYGIENE PRODUCTS AB
  • EP2654646B1 patent drawingFigure 1~3

AI summary

An absorbent article for absorbing liquid discharge of a wearer when worn in the crotch region,, the liquid discharge being urination, menstruation or liquid faecal matter. The absorbent article comprises at least one conductive loop in an open loop shape having terminal ends for electrically communicating with opposing poles of an electric potential generator such that current flows around the full conductive loop between the terminal ends when a space defined within the open loop shape is dry and such that liquid discharge in the space defined within the open loop shape is able to cause a short circuit in the conductive loop so that the current flows around a reduced impedance path as compared to the impedance of the full conductive loop. The impedance change is measureable to determine a location relative to the terminal ends where the liquid discharge has caused the short circuit. The at least one conductive loop is a first conductive loop. The article further comprises a second such conductive loop. The first and second conductive loops are oriented such that the direction in which the current travels up an outward leg of the respective conductive loop is in substantially the opposite direction for the first conductive loop as for the second conductive loop.