Cantilever MEMS Pressure Sensor for Harsh Environments
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Pressure sensor devices using MEMS technology face challenges with high static pressures, fast pressure transients, and freezing media, leading to damage and reliability issues, particularly in automotive and emission control systems, and existing solutions are costly, complex, or prone to failure.
Innovation Solution
A pressure sensor device with a cantilever-suspended MEMS pressure sensor element within a device package, where the element is fixed at one end to a side wall and surrounded by a fluid, using a substrate and membrane layers to define a closed cavity, eliminating the need for oil filling and protective gels, and allowing for robust operation in harsh conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If MEMS pressure sensor devices are used in high static pressures and fast pressure transients, then pressure measurement capability is improved, but the device becomes vulnerable to damage from pressure surges
Solution Approach 1:
The patent applies beforehand cushioning by introducing oil into the sealed cavity surrounding the MEMS pressure sensor element. This oil acts as a cushioning medium that absorbs and dampens pressure surges and transients before they reach the sensor element, protecting it from damage while allowing accurate pressure measurement. The oil-filled cavity serves as a protective buffer that mitigates the harmful effects of pressure cavitation and rapid pressure changes.
2Object-affected harmful factors
If protective gels are used to protect wire bonding from freezing media, then immunity to freezing is improved, but the gel cannot withstand high static or dynamic pressure levels
Solution Approach 1:
The patent uses oil as an intermediary substance that fills the cavity and surrounds both the MEMS pressure sensor element and the wire bonding. This oil intermediary provides dual protection: it protects the wire bonding from freezing media while simultaneously withstanding high static and dynamic pressure levels. The oil acts as a mediator that transmits pressure to the sensor element while protecting sensitive components from harmful environmental factors.
3Strength
If oil filled pressure sensor devices are used to provide immunity to high static pressures, then pressure resistance is improved, but the device structure becomes complex and cost increases
Solution Approach 1:
The patent merges the protective function with the pressure sensing function by using the same oil-filled sealed cavity for both purposes. The oil provides pressure resistance and protection against pressure surges, while the MEMS sensor element immersed in the same oil performs accurate pressure measurement. This merging eliminates the need for separate protective structures and complex damping mechanisms, simplifying the overall device design while maintaining pressure resistance.
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 solution provides robust pressure sensing capabilities without vulnerability to high pressures or freezing, reduces component complexity and cost, and protects wire bonding, enabling reliable operation in hostile environments.
Implementation Method 1
The membrane carries a strain gauge in such a way that one side of the metallic membrane is in fluid communication with a medium to be measured
Data Source
AI summary
A pressure sensor device comprises a device package (110) arranged to define a cavity (116) having an opening for fluid communication with an internal volume thereof. The cavity (116) comprises a side wall (114, 115). An elongate pressure sensor element (100) is provided and has a proximal end (120) and a distal end (122). The side wall (114, 115) is arranged to hold fixedly the proximal end (120) of the pressure sensor element (100) therein so that the pressure sensor element (100) is cantilever-suspended from the side wall (114, 115) within the cavity (116).