Piezoelectric MEMS Microphone Cantilever Beam Width Variation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional piezoelectric MEMS microphones face challenges with high power consumption and reliability issues, especially in harsh environments, and there is a need for improved sensitivity and reduced size.
Innovation Solution
The use of a cantilevered sensor design in piezoelectric MEMS microphones, where the beam width is greater at the distal tip than at the proximal portion anchored to the substrate, enhancing performance and allowing for a smaller device area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the beam width is increased at the distal tip to improve sensitivity and output energy, then the device area increases
Solution Approach 1:
The patent applies local quality by varying the beam width along its length, with the distal tip having a greater width than the proximal portion. This localized widening at the distal tip enhances sensitivity and output energy where it is most needed for acoustic detection, while keeping the proximal portion narrower to minimize overall device area. The non-uniform width distribution optimizes the balance between sensitivity and compactness.
2Measurement precision
If conventional capacitive MEMS microphones are used, then they provide adequate sensitivity, but they consume high power and have reliability issues in harsh environments
Solution Approach 1:
The patent replaces the capacitive sensing mechanism with a piezoelectric sensing mechanism. Instead of using capacitive plates and bias voltages, the invention employs piezoelectric materials that generate electrical charge directly in response to mechanical stress from acoustic waves. This substitution eliminates the need for high bias voltages, reduces power consumption, and improves reliability in harsh environments while maintaining or enhancing sensitivity.
3Power
If the beam width is greater at the distal tip than at the proximal portion, then output energy is increased, but manufacturing complexity increases
Solution Approach 1:
The patent applies parameter changes by modifying the geometric parameters of the beam, specifically the width distribution along its length. By changing the width parameter from uniform to non-uniform (greater at distal tip, smaller at proximal portion), the output energy is enhanced. This geometric parameter modification can be achieved through standard photolithography and etching processes, making it compatible with existing MEMS manufacturing techniques while improving performance.
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 achieves increased output energy and improved sensitivity, enabling the same performance as conventional sensors in a smaller size or maintaining performance while reducing the device area.
Implementation Method 1
Piezoelectric MEMS microphones have been used to address the deficiencies of capacitive MEMS microphones
Data Source
AI summary
An acoustic sensor (e.g., for use in a piezoelectric MEMS microphone) includes a substrate and a cantilever beam attached to the substrate. The cantilever beam has a proximal portion attached to the substrate and extending to a distal tip at a free end of the beam. The cantilevered beam has a width in plan view that is greater at a location distal of the proximal portion than at the proximal portion attached to the substrate. One or more electrodes are disposed on or in the proximal portion of the beam.