Nested Mesh Backplate for MEMS Microphone
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Solution Overview
Problem
MEMS microphone systems face a trade-off between sensitivity and noise, where smaller vent holes enhance sensitivity but increase acoustic noise, and a thinner backplate reduces noise but compromises strength and robustness.
Innovation Solution
A backplate design featuring two nested mesh patterns with different heights and widths, where the second mesh pattern is contained within the openings of the first, providing structural strength while allowing air passage and particle filtering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If smaller vent holes are used, then sensitivity is improved and particle filtering is enhanced, but acoustic noise increases
Solution Approach 1:
The backplate is divided into multiple mesh patterns with different aperture sizes. The first mesh pattern provides larger apertures for structural strength and noise reduction, while the second mesh pattern with smaller apertures provides particle filtering and maintains sensitivity. This segmentation allows each mesh to optimize for different functions without compromising the others.
Solution Approach 2:
The second mesh pattern is nested within the openings of the first mesh pattern, creating a hierarchical structure where the finer mesh is supported by the coarser structural frame. This nesting allows the smaller apertures for particle filtering to be integrated within the larger aperture structure, achieving both sensitivity and noise reduction.
2Object-generated harmful factors
If a thinner backplate is used, then acoustic noise is reduced, but strength and robustness deteriorate
Solution Approach 1:
The backplate structure is segmented into multiple mesh patterns with different functions. The first mesh pattern provides structural support and strength, while the second mesh pattern reduces acoustic noise through its finer apertures. This segmentation allows each layer to optimize for its specific function without compromising overall performance.
Solution Approach 2:
The backplate employs a composite structure combining two different mesh patterns with different aperture sizes and material properties. The coarser first mesh provides structural strength while the finer second mesh reduces acoustic noise, creating a composite structure that achieves both strength and noise reduction simultaneously.
Data Source
Figure 1
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Figure 3a
AI summary
A MEMS backplate. The MEMS backplate includes a first mesh pattern having a first height and a first arrangement of openings, and a second mesh pattern having a second height and a second arrangement of vent hole apertures. The second mesh pattern is contained within the opening formed by the first mesh pattern.