Mismatched Electrode Capacitor for Non-Destructive Liquid Detection
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Solution Overview
Problem
Existing methods for detecting liquid and/or humidity in structures are non-destructive and reliable, particularly in situations where access is restricted, such as under impermeable surfaces, as they often rely on unpredictable hygroscopic electrolytes that provide unreliable moisture detection.
Innovation Solution
A sensor device with a resonance circuit comprising an inductor and a capacitor with intentionally mismatched electrodes, which increases parasitic capacitance when a polar solvent like water is present, allowing for non-destructive detection of liquid and/or humidity by measuring changes in resonance frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hygroscopic electrolyte is used for moisture detection, then detection capability is provided, but reliability deteriorates due to unpredictable reaction to moisture
Solution Approach 1:
The patent changes the detection parameter from chemical reaction (hygroscopic electrolyte) to physical property (parasitic capacitance). By measuring capacitance changes caused by water's dielectric properties rather than chemical absorption, the system achieves reliable and predictable detection without the variability inherent in chemical methods.
Solution Approach 2:
The patent replaces the chemical/mechanical hygroscopic electrolyte system with an electrical field-based capacitance measurement system. This substitution eliminates the unpredictable chemical reactions while maintaining the ability to detect moisture through a more stable and controllable physical measurement approach.
2Strength
If surface is made impermeable for covering, then structural integrity is improved, but detection capability deteriorates as electrical measurement becomes impossible
Solution Approach 1:
The patent makes the sensor device universally applicable by enabling it to function through impermeable surfaces. The sensor can detect moisture both when embedded in structures and when placed under impermeable coverings, eliminating the need for surface access or destruction while maintaining detection capability across multiple application scenarios.
Solution Approach 2:
The patent introduces the impermeable surface itself as part of the sensing system rather than treating it as an obstacle. The surface becomes an intermediary layer that the sensor can detect through, using the sensor's ability to measure capacitance changes that occur regardless of surface permeability.
3Difficulty of detecting and measuring
If destructive access is made to interior for measurement, then measurement accessibility is improved, but structural damage occurs requiring costly restoration
Solution Approach 1:
The patent performs preliminary action by embedding the sensor device during the construction phase rather than attempting measurement after construction is complete. This timing allows the sensor to be integrated into the structure before impermeable surfaces are applied, eliminating the need for future destructive access while enabling continuous or periodic non-invasive monitoring.
Solution Approach 2:
The patent enables the structure to self-monitor its own condition through the embedded sensor. The sensor continuously or periodically assesses moisture levels within the structure without requiring external intervention or destructive sampling, allowing the structure to detect and report its own health status autonomously.
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 reliable and non-destructive detection of liquid and/or humidity by varying the resonance frequency of the sensor device, effectively addressing the limitations of existing technologies through increased sensitivity and accuracy.
Implementation Method 1
a sensor device with a resonance circuit comprising an inductor and a capacitor with intentionally mismatched electrodes, which increases parasitic capacitance when a polar solvent like water is present, allowing for non-destructive detection of liquid and/or humidity by measuring changes in resonance frequency
Implementation Method 2
the capacitor comprises a first electrode and a second electrode together sandwiching at least a portion of a dielectric substrate. The first and second electrodes are configured to provide an overlap mismatch relative to each other, and the overlap mismatch area is at least 0.1% of the overlapping area of the two electrodes
Implementation Method 3
the dielectric substrate comprises a homogeneous material having a dielectric constant which is variable in response to liquid and/or humidity in its environment
Data Source
AI summary
The present invention relates to a sensor device (10) for detection of liquid and/or humidity. The sensor device comprises a resonance circuit comprising an inductor (13) connected to a capacitor (11), wherein the capacitor comprises a first electrode (11a) and a second electrode (11b) together sandwiching at least a portion of a dielectric substrate (14). The first and second electrodes are configured to provide an overlap mismatch relative to each other, and the overlap mismatch area (ma) is at least 0.1% of the overlapping area (oa) of the two electrodes. The present invention further relates to a system (70) for reading a sensor device and a method (100, 200) for reading a sensor device.