Capacitive Wetness Sensor for Absorbent Articles
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Solution Overview
Problem
Current incontinence monitoring systems for absorbent articles, such as diapers, rely on manual insertion of sensors, which are costly and labor-intensive, and are challenging to integrate into high-speed manufacturing processes, leading to inefficiencies in detecting wetness events and managing incontinence effectively.
Innovation Solution
A sensor device with capacitive or resonance-based sensing elements is integrated into absorbent articles, allowing for either direct or contactless communication with a receiver, enabling reliable detection of wetness events and incorporating features like flow control and compensation for external environmental factors, such as movement, to improve accuracy and ease of manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex sensors are used for wetness detection, then measurement precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent employs a simple capacitive sensor structure consisting of basic conductive elements that can be easily manufactured and disposed of. This disposable approach eliminates the need for complex, expensive sensors while maintaining adequate detection functionality for the intended use period.
Solution Approach 2:
The patent replaces complex mechanical sensor systems with a simplified capacitive sensing mechanism. By using electrical field-based detection rather than mechanical contact or complex electronic components, the system achieves wetness detection with fewer parts and lower manufacturing complexity.
2Ease of operation
If manual insertion of sensors is used, then ease of operation is improved, but productivity and manufacturing efficiency deteriorate
Solution Approach 1:
The patent combines the sensor fabrication process with the absorbent article manufacturing process. The capacitive sensor elements are formed integrally with the absorbent layers during the same high-speed production line operation, eliminating separate manual insertion steps while maintaining ease of integration.
Solution Approach 2:
The patent changes the manufacturing parameter from manual assembly to automated high-speed fabrication. By modifying how the sensor is created (forming conductive elements directly during paper/absorbent layer production) rather than how it's assembled, the system achieves both simplicity and high productivity.
3Productivity
If high-speed manufacturing is used, then productivity is improved, but manufacturing precision and sensor positioning accuracy deteriorate
Solution Approach 1:
The patent performs preliminary formation of the capacitive sensor elements during the absorbent article manufacturing process itself. By creating the conductive layers and sensor structures as part of the base material fabrication before final assembly, precise positioning is achieved through the inherent precision of the paper/absorbent layer production equipment operating at high speed.
Solution Approach 2:
The manufacturing process serves itself by integrating sensor fabrication into the existing high-speed production line. The same equipment that manufactures the absorbent layers also creates the sensor elements, eliminating the need for separate precision positioning operations and maintaining both speed and accuracy.
4Productivity
If automated sensor insertion is attempted, then productivity is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent extracts the sensor fabrication step from the post-manufacturing assembly process and places it within the material production phase. By taking out the complex insertion operation entirely and replacing it with integral formation of sensor elements during absorbent layer manufacturing, automated integration becomes straightforward without requiring complex insertion machinery.
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 enhances the reliability and efficiency of wetness detection in absorbent articles, reducing resource consumption and improving patient care by providing accurate and automated monitoring of incontinence events, while minimizing disruptions and costs associated with manual checks.
Implementation Method 1
A sensor device with capacitive or resonance-based sensing elements is integrated into absorbent articles
Implementation Method 2
The change in electrical behaviour is observable as a change in capacitance arising from a change in the permittivity of the dielectric region
Implementation Method 3
A sensor device with capacitive or resonance-based sensing elements is integrated into absorbent articles
Data Source
Figure 1a~1b
Figure 2a~2b
Figure 3a~3b
AI summary
A sensor device for sensing wetness in an absorbent article worn by a subject includes one or more sensing elements; and a coupling for communicating sensor signals between the one or more sensing elements and a receiver. A change in environmental parameter causes a change in electrical behavior of at least one of the sensing elements, which behavior can be analyzed to determine occurrence of a wetness event in the absorbent article. The changes in electrical behavior are communicated in the sensor signals to the receiver. The analysis may be by the receiver or a processor in communication with the receiver. Ideally, the sensing elements include capacitive elements and preferably, resonance circuits.