MEMS Sensor Pressure Relief via Segmented Gas Flow Zone
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Solution Overview
Problem
MEMS sensors are prone to diaphragm damage due to strong winds or instantaneous high pressure changes, and existing pressure relief holes compromise sensing performance and elasticity, offering limited protection against pressure differences.
Innovation Solution
The MEMS sensor design includes a support structure that isolates a gas flow zone from an electrical coupling zone, using a pressure relief film to manage pressure changes by allowing gas to pass through the gas flow zone, thereby preventing diaphragm damage and maintaining sensing capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressure relief holes are added to the diaphragm, then pressure balance is adjusted, but sensing performance and elasticity deteriorate
Solution Approach 1:
The patent divides the sensor into two independent zones: an electrical coupling zone for sensing and a gas flow zone for pressure relief. The support structure with inner and outer walls creates separate chambers, isolating the pressure relief function from the sensing function. This segmentation allows pressure relief holes to be added without compromising sensing performance.
Solution Approach 2:
The support structure acts as an intermediary element between the diaphragm and the electrode plate. It creates a gas flow zone that serves as a mediator for pressure equalization, while the electrical coupling zone maintains the sensing function. The support structure transmits mechanical support while isolating the two functional zones.
2Stress or pressure
If more pressure relief holes are added, then instantaneous high pressure is relieved, but diaphragm elasticity decreases
Solution Approach 1:
The patent transitions from a two-dimensional diaphragm surface to a three-dimensional gas flow zone. By creating a volumetric space between the diaphragm and electrode plate with support walls, the pressure relief function is expanded into a third dimension, allowing larger pressure relief areas without compromising diaphragm integrity.
Solution Approach 2:
The support structure with its inner and outer walls creates a flexible gas flow zone that can expand and contract with pressure changes. This flexible chamber design allows for significant pressure relief capability while maintaining the structural integrity and elasticity of the diaphragm.
3Reliability
If gas flow zone and electrical coupling zone are not isolated, then pressure relief is effective, but low-frequency response decreases
Solution Approach 1:
The support structure segments the sensor interior into distinct gas flow and electrical coupling zones. The inner wall specifically isolates the gas flow zone from the electrical coupling zone, preventing gas leakage from affecting the sensing diaphragm's low-frequency response while maintaining pressure relief effectiveness.
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 design effectively balances internal and external pressures, reducing diaphragm damage and maintaining sensitivity and reliability by isolating pressure relief from electrical coupling, ensuring efficient pressure management without affecting sensing performance.
Implementation Method 1
When the air pressure changes inside or outside the MEMS sensor, the gas acts and passes through the gas flow zone to be discharged into the environment or into the MEMS sensor, thereby adjusting the pressure balance inside and outside the MEMS sensor
Data Source
AI summary
A MEMS sensor including an electrode plate, a diaphragm structure, a support structure, and a pressure relief film. The electrode plate has a conductive portion. The diaphragm structure is disposed at a side of the electrode plate with an interval, and has a sensing film. The support structure is disposed between the diaphragm structure and the electrode plate, and surrounds an electrical coupling zone and a gas flow zone. The support structure includes an inner wall and an outer wall. An outer edge of the gas flow zone is surrounded by the inner wall. An outer edge of the electrical coupling zone is surrounded by the outer wall. The pressure relief film covers the gas flow zone.