Capacitive Sensor Protection Layer for Liquid Level Detection
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Solution Overview
Problem
Existing capacitive sensors for liquid level detection lack sensitivity and are prone to corrosion and chemical damage, making them unsuitable for applications requiring high sensitivity and resistance to environmental factors.
Innovation Solution
A capacitive sensor design featuring an insulating layer with first and second detection electrodes and a protection layer made of zirconia or alumina, with a thickness between 1 μm and 10 μm, to enhance corrosion and chemical resistance while maintaining high sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protection layer is added to protect electrodes from corrosion and chemical damage, then reliability is improved, but sensitivity decreases
Solution Approach 1:
The patent changes the parameter of protection layer thickness to an optimal range (1-10 μm) and selects materials with high dielectric constants (zirconia, alumina) to maintain sensitivity while providing adequate corrosion protection. This resolves the contradiction by finding the right balance between protection and detection capability.
Solution Approach 2:
The patent uses composite material structures combining the protection layer with the insulating layer and electrodes, selecting materials with specific properties (high dielectric constant, chemical resistance) to achieve both protection and sensitivity requirements simultaneously.
2Reliability
If a thick protection layer is used to ensure corrosion resistance, then reliability is improved, but detection sensitivity decreases
Solution Approach 1:
The patent specifies an optimal thickness range (1-10 μm) for the protection layer, avoiding both too thin (insufficient protection) and too thick (reduced sensitivity) extremes. This parameter optimization resolves the contradiction between protection and detection.
Solution Approach 2:
The protection layer is applied with specific local properties (thickness control, material selection) only where needed for electrode protection, maintaining optimal characteristics for both corrosion resistance and capacitance detection in different regions of the sensor structure.
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 proposed sensor achieves high sensitivity in liquid level detection while ensuring corrosion and chemical resistance, effectively addressing the limitations of existing technologies.
Implementation Method 1
The protection layer covers the first detection electrode and the second detection electrode, has a thickness d satisfying 1 μm≤d≤10 μm, and is made of zirconia or alumina
Implementation Method 2
The second detection electrode is provided away from the first detection electrode on the insulating layer, and forms the capacitance together with the first detection electrode. A liquid level is calculated based on a magnitude of a capacitance between electrodes.
Data Source
AI summary
A first detection electrode is provided on an insulating layer. A second detection electrode is provided away from the first detection electrode on the insulating layer, and forms a capacitance together with the first detection electrode. The protection layer covers the first detection electrode and the second detection electrode, has a thickness d satisfying 1 μm≤d≤10 μm, and is made of zirconia or alumina. The protection layer is a sintered body.