Piezoelectric MEMS Microphone Diaphragm Segmentation
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Solution Overview
Problem
The sensitivity of piezoelectric MEMS microphones is limited, making it difficult to further improve their performance without enhancing the structural design.
Innovation Solution
A piezoelectric MEMS microphone design featuring a base with a cavity, a piezoelectric diaphragm, a fixation beam, and a support beam, where the diaphragm sheets are fixed by the fixation beam with free ends extending to both sides and supported by the support beam, allowing for increased mechanical strength and resonance frequency, and incorporating elastic structures between adjacent sheets for synchronous vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the diaphragm sheet uses a cantilever structure with one end fixed and the other end free, then the deformation caused by residual stress is reduced, but the sensitivity is limited and difficult to improve
Solution Approach 1:
The diaphragm sheet is divided into multiple segments (first diaphragm sheet and second diaphragm sheet) that can vibrate independently. Each segment has its own free end that generates voltage under sound pressure, effectively multiplying the output signal and improving sensitivity while maintaining the stability benefits of the cantilever structure
2Strength
If the free end length is shortened, then the mechanical strength is enhanced, but the vibration amplitude may be reduced
Solution Approach 1:
Instead of having one long free end, the structure uses multiple shorter free ends (first free end and second free end) that segment the vibration function. This maintains mechanical strength by keeping individual free end lengths short while still providing sufficient vibration amplitude through the combined effect of multiple segments
3Measurement precision
If multiple diaphragm sheets are used to improve sensitivity, then the output intensity increases, but the structural complexity increases
Solution Approach 1:
Multiple diaphragm sheets are merged into a single integrated piezoelectric diaphragm structure where the sheets share common fixed ends and are connected through the piezoelectric material. This unified structure reduces manufacturing complexity and assembly steps compared to separate components, while still achieving enhanced sensitivity through the combined vibration and voltage generation of multiple free ends
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 the mechanical strength and sensitivity of the microphone by shortening the free end length, increasing resonance frequency, and enabling simultaneous voltage generation from both free ends, thereby improving signal output intensity.
Implementation Method 1
electric charges are generated through the piezoelectric material
Data Source
AI summary
A piezoelectric MEMS microphone is disclosed. The microphone includes a base having a cavity; a piezoelectric diaphragm; a fixation beam connecting with the piezoelectric diaphragm; and a support beam connecting with the base and the fixation beam. The piezoelectric diaphragm has a number of diaphragm sheets fixed by the fixation beam, each diaphragm sheet having a fixed end and a free end. The fixed end is connected with the fixation beam, and the free end extends from the fixed end to two sides and is suspended above the cavity. Compared with the related art, mechanical strength of the diaphragm sheet is improved, and the output intensity of the signal is improved.