MEMS Microphone Vibration Isolation via Support Layer
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Solution Overview
Problem
MEMS microphones used in vehicle environments face challenges in minimizing vibration noise due to cyclically occurring vibrations, which affect sensitivity and signal quality, as existing noise removal methods are inadequate for such robust noise conditions.
Innovation Solution
A microphone design featuring a substrate with an oxide layer, a vibration electrode supported by a separate support layer, a fixed electrode, and a back plate with air passages and penetration holes, which isolates the vibration electrode from substrate vibrations, minimizing noise through controlled vibration displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the vibration electrode is directly connected to the substrate, then the structural simplicity is improved, but the vibration noise increases due to substrate vibrations
Solution Approach 1:
The patent introduces a support layer as an intermediary component between the substrate and the vibration electrode. This support layer is separated from the substrate and provides mechanical support to the vibration electrode without being directly connected to the substrate, thereby isolating the vibration electrode from substrate-induced vibrations and reducing vibration noise while maintaining structural simplicity.
2Reliability
If a robust structure is used to resist vibration, then the vibration resistance is improved, but the sensitivity to sound signals decreases
Solution Approach 1:
The patent segments the structural support function from the sound sensing function. The support layer provides mechanical support and vibration isolation, while the vibration electrode maintains its sensitivity to sound signals. This segmentation allows the structure to be robust against vibration while preserving the sensitivity of the sensing element.
Solution Approach 2:
The patent applies different structural qualities to different parts of the system. The support layer has high mechanical strength and is separated from the substrate to provide vibration resistance, while the vibration electrode maintains its delicate structure and high sensitivity for sound signal detection. This local differentiation of structural properties resolves the contradiction between robustness and sensitivity.
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 effectively suppresses substrate-induced vibrations, reducing noise interference and enhancing sensitivity to sound signals in noisy environments like vehicles.
Implementation Method 1
a microphone including: a substrate including an audio hole and having an oxide layer at a predetermined segment along an upper surface edge; a vibration electrode that is supported by a support layer that is formed along an upper surface edge in a state that is separated to the inside of the center from the oxide layer at an upper portion corresponding to the audio hole; a fixed electrode that is formed at an upper portion of the oxide layer
Data Source
AI summary
A Micro Electro Mechanical System (MEMS) microphone is provided. The MEMS microphone includes: a substrate including an audio hole and having an oxide layer at a predetermined segment along an upper surface edge; a vibration electrode that is supported by a support layer that is formed along an upper surface edge in a state that is separated to the inside of the center from the oxide layer at an upper portion corresponding to the audio hole; a fixed electrode that is formed at an upper portion of the oxide layer and in which one side of the support layer is bonded to one side of a low surface; and a back plate that is formed at an upper portion of the fixed electrode and in which the other side of the support layer is bonded to one side of a low surface.