MEMS Microphone Diaphragm Vent Valves Air Blow Durability
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Solution Overview
Problem
MEMS microphones face a trade-off between sensitivity and durability, as increasing the rigidity of the diaphragm to withstand air blow tests reduces sensitivity, and increasing the open ratio to enhance sensitivity also compromises durability and low-frequency response.
Innovation Solution
The implementation of wing vent valves or vortex vent valves on the diaphragm, which alter the deflection pattern and gap changes between the diaphragm and backplate, enhancing sensitivity while improving the diaphragm's ability to pass air blow tests without significant rigidity degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rigidity of the diaphragm is increased to withstand air blow tests, then durability is improved, but sensitivity deteriorates
Solution Approach 1:
The patent applies local quality by creating anchor areas with different rigidity characteristics. The diaphragm has regions with varying rigidity: anchor areas near the boundary that are more rigid to withstand air blow tests, and central areas that remain flexible for sensitivity. This is achieved through selective etching patterns that create different structural densities in different regions of the diaphragm.
Solution Approach 2:
The diaphragm is segmented into multiple functional regions through the etching pattern design. The structure is divided into anchor areas (near boundaries) and non-anchor areas (central regions), each with different rigidity properties. This segmentation allows the diaphragm to simultaneously achieve durability in anchor areas and sensitivity in non-anchor areas.
2Measurement precision
If the open ratio is increased to enhance sensitivity, then sensitivity is improved, but durability and low-frequency response deteriorate
Solution Approach 1:
The etching pattern creates local quality variations where anchor areas have lower open ratios (higher rigidity) and non-anchor areas have higher open ratios (lower rigidity). This allows the diaphragm to maintain durability in anchor areas while achieving sensitivity enhancement in non-anchor areas through increased local open ratios.
3Measurement precision
If the open ratio is increased to enhance sensitivity, then sensitivity is improved, but low-frequency response deteriorates
Solution Approach 1:
The patent uses local quality to maintain low-frequency response by keeping anchor areas (which affect low-frequency response) with lower open ratios, while enhancing sensitivity in non-anchor areas with higher open ratios. The selective etching pattern ensures that low-frequency response characteristics are preserved in critical regions.
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 design increases the sensitivity of the MEMS microphone while allowing it to withstand common air blow tests, with controlled deflection ranges and potential rigidity enhancement through annealing processes.
Implementation Method 1
The diaphragm is deformable by sound waves to cause gaps between the backplate and the diaphragm being changed at multiple locations on the diaphragm
Implementation Method 2
potential rigidity enhancement through annealing processes
Data Source
AI summary
A MEMS microphone includes a backplate that has a plurality of open areas, and a diaphragm spaced apart from the backplate. The diaphragm is deformable by sound waves to cause gaps between the backplate and the diaphragm being changed at multiple locations on the diaphragm. The diaphragm includes a plurality of anchor areas, located near a boundary of the diaphragm, which is fixed relative to the backplate. The diaphragm also includes multiple vent valves. Examples of the vent valve include a wing vent valve and a vortex vent valve.