MEMS Pressure Sensor with Magnetic Actuator for Linearity
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Solution Overview
Problem
Conventional MEMS pressure sensors have limited operational range and linearity, especially when exposed to high pressures such as those found underwater, leading to inaccurate readings due to membrane deflection and contamination detection challenges.
Innovation Solution
A multifunction magnetic and piezoresistive MEMS device that combines a magnetic out-of-plane actuator with piezoresistive pressure sensors, utilizing magnetic coils to reduce membrane deflection and enable extended pressure sensing range, and includes features for contamination detection and temperature measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional MEMS pressure sensors are used for underwater pressure sensing, then the sensor can detect pressure changes, but the linearity decreases and measurement precision deteriorates at high pressures due to membrane deflection
Solution Approach 1:
A magnetic actuator is introduced as an intermediary component that applies a counteracting force to the membrane. This mediator force compensates for the membrane deflection caused by high pressure, thereby maintaining linearity and measurement precision across extended pressure ranges including underwater conditions.
Solution Approach 2:
The magnetic actuator dynamically adjusts the membrane's mechanical properties by applying variable magnetic force. This parameter change in the magnetic field allows the membrane to maintain optimal deflection characteristics across different pressure conditions, resolving the linearity degradation issue at high pressures.
2Adaptability or versatility
If the pressure sensing range is extended to underwater depths, then more applications become possible, but false readings occur due to water evaporation and contamination
Solution Approach 1:
The magnetic actuator serves dual purposes: it compensates for membrane deflection at high pressures while simultaneously counteracting the harmful effects of water evaporation and contamination on the membrane. By applying magnetic force, the system converts the problematic interaction between water and membrane into a controlled mechanical interaction, preventing false readings.
3Adaptability or versatility
If a magnetic actuator is added to compensate for membrane deflection, then pressure sensing range is extended, but device complexity increases
Solution Approach 1:
The magnetic actuator is designed to perform multiple functions simultaneously: it compensates for membrane deflection at high pressures, counteracts water evaporation effects, and maintains membrane positioning accuracy. This multi-functionality justifies the added component by resolving multiple issues with a single mechanism, thereby limiting the increase in device complexity.
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 accurate underwater pressure sensing, reduces false readings from water evaporation, and provides integrated functionality for temperature measurement and contamination detection, enhancing the reliability of pressure sensing in diverse environments.
Implementation Method 1
one or more piezoresistive elements disposed on the membrane and configured to sense a displacement due to a deflection of the membrane
Implementation Method 2
A magnetic actuator is disposed inside a cavity of the housing. The magnetic actuator exerts a repulsive force onto the membrane in order to reduce the deflection of the membrane
Data Source
AI summary
Aspects of the subject disclosure include a pressure-sensing device consisting of a housing including a membrane and one or more piezoresistive elements disposed on the membrane to sense a displacement due to a deflection of the membrane. A first set of electrodes is disposed over the membrane, and a second set of electrodes is disposed on a permeable port of the device at a distance from the membrane. The first and second sets of electrodes form an electrostatic actuator to exert a repulsive force onto the membrane to reduce the deflection of the membrane.