MEMS Microphone Diaphragm T-Shaped Support for Larger Displacement
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Solution Overview
Problem
The small vibration displacement range of the diaphragm in MEMS microphones due to the use of cantilever beams reduces the sensitivity of the microphone.
Innovation Solution
A T-shaped beam support structure is introduced, comprising a cantilever portion and two anchoring portions extending in opposite directions along the circumferential direction of the vibrating portion, with specific dimensions and fillets to enhance deformation and stiffness, and convex columns for contact points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a cantilever beam is used as the support structure, then the diaphragm can be supported with simple structure, but the vibration displacement range is small which reduces sensitivity
Solution Approach 1:
The support structure is segmented into multiple components: a cantilever portion extending from the vibrating portion, and multiple anchoring portions connected to the end of the cantilever portion. This segmentation allows each part to perform specific functions - the cantilever portion provides flexibility for vibration while the anchoring portions provide stable support points, collectively increasing the vibration displacement range without excessive complexity
Solution Approach 2:
The support structure transitions from a simple one-dimensional cantilever beam to a two-dimensional T-shaped configuration by adding anchoring portions that extend in opposite directions along the circumferential direction. This dimensional change increases the moment of inertia and allows for larger vibration displacement range while maintaining structural stability
2Stability of the object's composition
If the cantilever beam deformation is small, then the structure is stable, but the sensitivity of the microphone is reduced
Solution Approach 1:
The support structure uses asymmetric T-shaped configuration where the cantilever portion and anchoring portions have different dimensions and orientations. The anchoring portions extend in opposite directions with specific length ratios, creating an asymmetric structure that optimizes both stability and sensitivity by distributing stress appropriately while allowing sufficient vibration amplitude
3Reliability
If the support structure provides sufficient support, then reliability is improved, but vibration displacement is limited
Solution Approach 1:
The support structure parameters are optimized with specific dimensional relationships: the anchoring portions have lengths within 60-80 μm, the cantilever portion has specific length and width ratios, and fillet radii are controlled within 5-15 μm. These parameter changes ensure the structure provides sufficient support for reliability while allowing adequate vibration displacement range
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 T-shaped beam design increases the vibration displacement range, improving sensitivity, compliance, and signal-to-noise ratio while minimizing wrinkling and stress, enhancing the microphone's reliability and robustness.
Implementation Method 1
The T-shaped beam has larger deformation than the cantilever beam has in the related art, so that a vibration displacement range of the diaphragm is larger
Implementation Method 2
a first fillet is formed at a joint of the cantilever portion and the first anchoring portion, a second fillet is formed at a joint of the cantilever portion and the second anchoring portion
Data Source
AI summary
Provided is a diaphragm and a micro-electromechanical system (MEMS) microphone. The diaphragm includes a vibrating portion and a support structure. The support structure includes a cantilever portion. Lengths of the first and second anchoring portion both extend along a circumferential direction of the vibrating portion, and a length extension direction of the first anchoring portion is opposite to that of the second one. The lengths of the first and second anchoring portions both extend along the circumferential direction of the vibrating portion, and the length extension direction of the first anchoring portion is opposite to that of the second one, so that the first and second anchoring portions and the cantilever portion are connected in a T shape. A vibration displacement range of the diaphragm is larger, thereby improving sensitivity and compliance of the MEMS microphone.