Guard Electrode Pressure Sensor for Condensation Noise
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional pressure sensors are susceptible to disturbances such as liquid condensation and electromagnetic noise, which can cause shifts in pressure output values due to stray capacitance and electrostatic interference.
Innovation Solution
The pressure sensor structure incorporates a guard electrode layer with a contact region on the electrical insulating film, maintaining the guard electrode and adhered liquid at the same potential, and a conductive film connected to the guard electrode, reducing the impact of liquid adhesion and electromagnetic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the pressure sensor structure is exposed to the outside air for pressure measurement, then pressure detection capability is improved, but susceptibility to liquid condensation and electromagnetic noise increases
Solution Approach 1:
The guard electrode layer acts as an intermediary element between the diaphragm plate and the external environment. By maintaining the guard electrode at a fixed potential through the contact region, it creates a shield that blocks electromagnetic noise and prevents liquid condensation from affecting the measurement, thus resolving the contradiction between exposure for measurement and protection from harmful factors
Solution Approach 2:
The contact region establishes equipotentiality between the guard electrode and the external environment by allowing the guard electrode to be at the same potential as the surrounding area. This prevents potential differences that would otherwise cause stray capacitance changes due to liquid adhesion or electromagnetic interference, while still permitting pressure measurement
2Reliability
If the guard electrode layer is completely covered with electrical insulating film for protection, then corrosion resistance is improved, but ability to maintain constant potential and block electromagnetic noise deteriorates
Solution Approach 1:
The electrical insulating film is applied selectively with a local exception at the contact region. The guard electrode layer is covered with the insulating film for corrosion protection, but the contact region remains exposed to maintain electrical connection with the external environment. This local quality differentiation allows the system to simultaneously achieve corrosion resistance and electromagnetic noise blocking capability
Solution Approach 2:
The surface of the guard electrode layer is segmented into two functional zones: a covered portion protected by the electrical insulating film for corrosion resistance, and an exposed contact region for maintaining potential reference. This segmentation allows each zone to perform its specific function without interfering with the other
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
This configuration enables highly accurate pressure measurements by minimizing the influence of disturbances like condensation and electromagnetic noise, while also providing corrosion resistance for use with corrosive liquids.
Implementation Method 1
A typical pressure sensor has a capacitor structure with two electrodes and can measure pressure by detecting a change in electrostatic capacitance caused by a change in ambient pressure
Implementation Method 2
the guard electrode layer and upper and lower guard electrode insulating layers electrically insulating the guard electrode layer
Data Source
AI summary
A pressure sensor structure includes a sensor body including a diaphragm plate defining and functioning as a sense electrode, a base electrode facing the diaphragm plate, and a sidewall layer maintaining a gap between the diaphragm plate and the base electrode, and a conductive base substrate supporting the sensor body. The sidewall layer includes a guard electrode layer and upper and lower guard electrode insulating layers electrically insulating the guard electrode layer. Surfaces of an outer side portion of each of the diaphragm plate and the sidewall layer are covered with an electrical insulating film that includes a contact region at which a portion of the guard electrode layer communicates with outside air.