MEMS Microphone Air Valve Plate for Sudden Pressure Protection
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Solution Overview
Problem
MEMS microphones face damage from sudden over-high air pressures due to the mechanical strength limitations of their flexible diaphragms, which are essential for sensing acoustic signals.
Innovation Solution
The integration of an air valve plate structure within the diaphragm, comprising a base plate, a swayable plate, and a spring joint, which activates to release sudden air pressures and protect the diaphragm from damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the diaphragm is made flexible to respond to acoustic signals, then the sensitivity to acoustic signals is improved, but the mechanical strength to resist sudden over-high air pressure deteriorates
Solution Approach 1:
The patent introduces an air valve plate as an intermediary component between the diaphragm and the sudden air pressure. The air valve plate includes a base plate affixed to the back-plate and a swayable plate connected by a spring joint. When sudden air pressure occurs, the swayable plate activates to open a venting hole, allowing air to escape and protecting the diaphragm from damage, while maintaining normal acoustic signal sensing functionality.
2Measurement precision
If the diaphragm is made flexible to respond to acoustic signals, then the acoustic signal sensing capability is improved, but the reliability under sudden air pressure deteriorates
Solution Approach 1:
The patent applies preliminary anti-action by pre-configuring the air valve plate mechanism that automatically activates in response to sudden air pressure. The spring joint pre-load the swayable plate in a closed position during normal operation, but when excessive pressure is detected, the mechanism automatically opens to release the harmful pressure, thereby protecting the diaphragm and improving reliability without affecting normal acoustic sensing.
3Reliability
If the air valve plate is added to protect the diaphragm, then the reliability under sudden air pressure is improved, but the device complexity increases
Solution Approach 1:
The patent merges the air valve plate structure with the existing back-plate of the MEMS microphone. The base plate of the air valve plate is affixed to the back-plate, and the venting hole is integrated into the back-plate structure. This merging approach allows the protection function to be added without requiring completely separate components, thereby reducing the increase in device complexity while maintaining reliability improvement.
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 air valve plate effectively mitigates the impact of sudden air pressures by allowing air flow to be released, thereby protecting the diaphragm and maintaining the sensitivity of the MEMS microphone to acoustic signals.
Implementation Method 1
a spring joint, connected between the base plate and the swayable plate. The swayable plate vibrates in response to the pressure of the air flow.
Implementation Method 2
a spring joint, connected between the base plate and the swayable plate
Implementation Method 3
a diaphragm, which is responding to the air pressure from the acoustic signal with a frequency, so to vibrate corresponding to the frequency and amplitude of the acoustic signal
Data Source
AI summary
In an embodiment, the invention provides a structure of MEMS microphone includes a substrate of semiconductor, having a first opening in the substrate. A dielectric layer is disposed on the substrate, having a dielectric opening. A diaphragm is within the dielectric opening and held by the dielectric layer at a peripheral region, wherein the diaphragm has a diaphragm opening. A back-plate is disposed on the dielectric layer, over the diaphragm. A protruding structure is disposed on the back-plate, protruding toward the diaphragm. At least one air valve plate is affixed on an end of the protruding structure within the diaphragm opening of the diaphragm. The air valve plate is activated when suffering an air flow with a pressure.