MEMS Microphone Electrode Assembly Structural Integrity
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Solution Overview
Problem
Current MEMS microphone systems face challenges in achieving optimal acoustic signal quality due to issues with noise artifacts and structural integrity, particularly in maintaining gas pressure and preventing debris ingress within the electrode region.
Innovation Solution
The proposed MEMS microphone system incorporates a driving system with a carrier and plate counter electrode assembly, featuring diaphragms made of low conductivity materials with tensile residual stress, and a sealed electrode region with encapsulated gas pressure, along with a leak hole in the pillar to manage pressure and prevent contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrode region is sealed to maintain gas pressure and prevent debris ingress, then reliability is improved, but manufacturing precision becomes more difficult due to the complexity of creating and sealing the encapsulated cavity
Solution Approach 1:
The sealed electrode region is formed as a distinct encapsulated cavity separate from the external environment, isolating the electrode components within a controlled internal space. This segmentation allows the cavity to be sealed independently, protecting internal components from external contaminants while maintaining manufacturing feasibility through separate processing steps.
Solution Approach 2:
The encapsulated cavity is formed and sealed during the manufacturing process before the microphone is deployed. By preliminarily creating the sealed structure and encapsulating the electrode region with controlled gas pressure during fabrication, the system ensures structural integrity and prevents debris ingress without requiring complex post-assembly sealing operations.
2Reliability
If diaphragms are made of low conductivity materials to reduce electrical interference, then reliability is improved, but acoustic signal quality deteriorates due to reduced sensitivity
Solution Approach 1:
The diaphragm is constructed with non-uniform electrical conductivity distribution. The peripheral portion of the diaphragm is made of low conductivity material to minimize electrical interference and improve reliability, while the central portion maintains higher conductivity to preserve acoustic signal sensitivity. This local quality differentiation resolves the contradiction between electrical stability and measurement precision.
3Reliability
If the electrode region is completely sealed to prevent contamination, then reliability is improved, but acoustic signal quality deteriorates due to pressure differential effects
Solution Approach 1:
A pressure equalization mechanism serves as an intermediary between the sealed electrode region and the external environment. This intermediary allows pressure differentials to be managed, enabling the electrode region to remain sealed for contamination prevention while accommodating pressure changes that occur during acoustic operation, thereby maintaining both reliability and acoustic signal quality.
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 design enhances acoustic signal quality by reducing artifact noise and improving the structural integrity of the microphone system, allowing for effective sound wave conversion into electrical signals while maintaining a controlled environment within the electrode region.
Implementation Method 1
The first and second diaphragms are substantially made of a material having a tensile residual stress
Implementation Method 2
the plate counter electrode assembly comprising a first movable electrode member and a second movable electrode member... one or more of the diaphragms are substantially made of a material having a tensile residual stress
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A microphone system includes first diaphragm element, second diaphragm element spaced apart from the first diaphragm element and connected to the first diaphragm element via a spacer. Disposed between the diaphragm elements is a plate capacitor element.