Variable Spacing Interdigitated Electrode for Gradient Material Sensing
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Solution Overview
Problem
Conventional capacitive proximity sensors with equal spacing interdigitated electrode structures are not suitable for detecting dielectric properties of polymer materials with thickness gradients, as they fail to confine the electric field effectively within the material, leading to suboptimal signal strength and sensitivity.
Innovation Solution
A novel capacitive proximity sensor with a variable spacing interdigitated electrode (VS-IDE) structure is designed, where the width and spacing of electrodes are optimized based on the local thickness of the sample, allowing the electric field to be confined within the material and improving signal strength and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional equal spacing interdigitated electrode structure is used, then device complexity is reduced and manufacturing is easier, but electric field confinement within the material is poor leading to suboptimal signal strength
Solution Approach 1:
The patent applies local quality by varying the spacing between adjacent electrodes in different regions of the interdigitated electrode structure. Specifically, the spacing is adjusted according to the local thickness of the sample being measured, creating non-uniform spacing that optimizes electric field distribution for samples with thickness gradients. This resolves the contradiction by improving signal strength through localized optimization without requiring complete redesign of the entire electrode structure.
Solution Approach 2:
The patent implements dynamics by making the electrode spacing adaptable to different sample configurations. The variable spacing design allows the electrode structure to dynamically adjust its electric field distribution based on the sample thickness profile, enabling optimal performance across different measurement scenarios rather than being fixed to a single spacing configuration.
2Measurement precision
If equal spacing interdigitated electrode structure is used, then manufacturing precision requirements are lower, but the sensor cannot effectively detect dielectric properties of materials with thickness gradients
Solution Approach 1:
The variable spacing electrode structure applies local quality by tailoring the spacing between electrodes to match the local thickness characteristics of the sample. This allows the sensor to accurately detect dielectric properties across thickness gradients by optimizing electric field penetration at each location, resolving the contradiction between measurement precision and manufacturing precision requirements.
3Reliability
If variable spacing interdigitated electrode structure is implemented, then electric field confinement within the material is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent resolves the manufacturing complexity issue by implementing variable spacing through a systematic design approach where spacing is adjusted locally based on sample thickness requirements. This allows standard fabrication techniques to be used while achieving improved electric field confinement, balancing manufacturing ease with performance optimization.
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 VS-IDE structure enhances the effective electrode area, increases signal strength, and effectively characterizes dielectric properties of materials with thickness gradients, enabling non-destructive testing and continuous online monitoring.
Implementation Method 1
Capacitance variation caused by the relative dielectric permittivity changed is closely related to the electrical properties of the polymer materials
Implementation Method 2
Capacitance variation caused by the relative dielectric permittivity changed is closely related to the electrical properties of the polymer materials
Implementation Method 3
capacitive proximity sensors are newly developed sensing technique based on the fringing effect of the electric field
Data Source
AI summary
Embodiments related to a capacitive proximity sensor with a variable spacing electrode structure, which is suited to a non-destructive testing operation, such as the detection of dielectric properties of the polymer materials with a thickness decreases gradually structure. The designed sensor includes a driving electrode, a sensing electrode, a substrate, a guarding electrode and a lead connector. The driving and sensing electrodes include several interdigitated fingers, which are arranged alternately in sequence, based on the characteristic of the thickness decreases gradually structure of the MUT, the width of the electrodes and spacing between two adjacent electrodes in each unit are optimized individually. Namely, under the condition of ensuring penetration depth, the electrode width is made as large as possible to achieve maximum signal strength and detection sensitivity. Compared with the traditional ES-IDE structure capacitive proximity sensor, the newly designed VS-IDE capacitive sensor increases the effective electrode area, which increases the signal strength and measurement sensitivity directly. Besides, the electric field lines of the designed sensor are confined within the thickness gradually changed materials under test mostly as expected simultaneously.