MEMS Diaphragm Ventilation Segmentation for Noise and Rigidity
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Solution Overview
Problem
Existing MEMS microphones with double-diaphragm structures face challenges in reducing self-noise and maintaining structural rigidity under high-pressure loads, particularly due to stress concentration and ventilation holes that affect the overall structure's rigidity.
Innovation Solution
The design includes a base with a rear cavity, concentrically arranged upper and lower diaphragms forming an accommodation space with a counter electrode, and supporting members with first cavities and ventilation holes that communicate, along with protrusions and through holes to enhance flexibility and mechanical support, reducing stress concentration and maintaining structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If ventilation holes are formed at the center of each diaphragm to reduce self-noise, then self-noise is reduced, but stress concentration occurs and structural rigidity is affected
Solution Approach 1:
The patent divides the ventilation function into multiple segments by forming multiple ventilation holes at different radial positions (including center and periphery) rather than a single hole. This segmentation distributes the stress concentration effect and maintains overall structural rigidity while achieving the noise reduction function.
Solution Approach 2:
The patent applies different ventilation hole configurations to different regions of the diaphragm. Central ventilation holes are combined with peripheral ventilation holes, creating a non-uniform distribution that optimizes both noise reduction and stress distribution. The supporting members also provide localized reinforcement at critical positions.
2Object-affected harmful factors
If the accommodation space pressure is reduced to reduce self-noise, then self-noise is reduced, but the overall structure rigidity is affected
Solution Approach 1:
The patent incorporates supporting members in advance during the structural design phase to preemptively counteract the rigidity reduction caused by pressure differential. These supporting members are positioned to provide mechanical reinforcement before the pressure differential fully develops, maintaining structural stability throughout operation.
Solution Approach 2:
The patent employs composite structural elements combining the diaphragm material with supporting member materials of different mechanical properties. This composite approach allows the structure to simultaneously achieve the necessary flexibility for vibration and the rigidity to maintain structural integrity under pressure differential.
3Strength
If supporting members are added to maintain structural rigidity, then structural rigidity is improved, but device complexity increases
Solution Approach 1:
The supporting members serve multiple functions simultaneously: they provide structural reinforcement to maintain rigidity, act as stress distribution elements to prevent concentration, and serve as mounting points for ventilation holes. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity.
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 configuration improves microphone sensitivity and stability by controlling acoustic resistance, reducing variability in the etching process, and distributing stress uniformly, while maintaining the local rigidity of the vibrating diaphragm, thus enhancing the mechanical sensitivity and reliability of the MEMS device.
Implementation Method 1
This configuration improves microphone sensitivity and stability by controlling acoustic resistance
Data Source
AI summary
Provided is an MEMS device, including: a base, a rear cavity; a vibrating diaphragm, the vibrating diaphragm including an upper diaphragm and a lower diaphragm, and an accommodation space being formed between the upper and lower diaphragms; a counter electrode arranged in the accommodation space; and supporting members concentrically arranged and spaced apart. The supporting members are arranged between the upper and lower diaphragms and are spaced apart from the counter electrode, two opposite ends of each supporting member are connected to the upper and lower diaphragms, and at least one of the supporting members is provided with first cavities. An upper ventilation hole and a lower ventilation hole are respectively formed at a position of the upper diaphragm and a position of the lower diaphragm corresponding to one of the first cavities; and the upper ventilation hole, the first cavity and the lower ventilation hole communicate with each other.