Corrugated Piezoelectric MEMS Sensor for Higher Sensitivity
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Solution Overview
Problem
Existing microelectromechanical transducers, such as microphones and vibration sensors, face challenges in sensitivity, robustness, and efficiency due to the use of conventional piezoelectric membranes that suffer from electrical field compensation and mechanical stress, leading to reduced voltage output and potential damage from extreme loads.
Innovation Solution
The integration of corrugated piezoelectric membranes with a central inertial mass and undulated sections, where piezoelectric unit cells are arranged to induce consistent electrical fields and absorb mechanical stresses, allowing for higher voltage output and improved sensitivity, while sharing ASICs for cost-effective manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional piezoelectric membranes are used in microelectromechanical transducers, then the device structure is simple, but the sensitivity and voltage output are reduced due to electrical field compensation and mechanical stress
Solution Approach 1:
The piezoelectric membrane is divided into multiple piezoelectric unit cells with different orientations. Specifically, the membrane contains first piezoelectric unit cells with piezoelectric layers oriented in a first direction and second piezoelectric unit cells with piezoelectric layers oriented in a second direction perpendicular to the first direction. This segmentation allows different regions to contribute to different components of the electrical field, preventing field compensation and enhancing sensitivity to acoustic waves and vibrations.
Solution Approach 2:
Different regions of the membrane are designed with different piezoelectric layer orientations to optimize local response characteristics. The first and second piezoelectric unit cells have locally differentiated piezoelectric layer orientations, enabling each region to respond optimally to specific stress components while collectively providing enhanced overall sensitivity without requiring complex external structures.
2Reliability
If conventional piezoelectric membranes are used, then manufacturing is simpler, but robustness is reduced due to potential damage from extreme mechanical loads
Solution Approach 1:
The membrane is segmented into multiple piezoelectric unit cells that can independently deform under mechanical load. This segmentation prevents stress concentration in single large membranes, reducing the risk of catastrophic failure from extreme loads while maintaining manufacturing feasibility through standardized unit cell replication.
Solution Approach 2:
The corrugated structure of the piezoelectric membrane provides inherent mechanical compliance and stress distribution capabilities before extreme loads are applied. The undulated geometry allows the membrane to accommodate mechanical stresses through controlled deformation of the corrugations, preventing damage while maintaining structural integrity.
3Measurement precision
If corrugated piezoelectric membranes with undulated sections are used, then sensitivity and robustness are enhanced, but manufacturing complexity increases
Solution Approach 1:
The corrugated membrane is divided into standardized piezoelectric unit cells with repeating patterns of undulations and piezoelectric layer orientations. This segmentation enables modular manufacturing where identical or similar unit cells can be produced using standard fabrication processes, reducing overall manufacturing complexity despite the enhanced corrugated structure.
Solution Approach 2:
The piezoelectric layers are oriented in specific directions (first and second perpendicular directions) to optimize sensitivity while maintaining compatibility with standard thin-film deposition and patterning processes. This parameter optimization allows enhanced performance to be achieved through controlled material orientation rather than complex structural modifications.
4Power
If piezoelectric unit cells with different piezoelectric layer orientations are used, then consistent electrical fields are induced and voltage output increases, but device complexity increases
Solution Approach 1:
The membrane is divided into first and second piezoelectric unit cells with piezoelectric layers oriented in perpendicular directions. This segmentation enables each unit cell type to generate specific electrical field components that combine to produce enhanced overall voltage output, while the modular nature of the unit cells keeps individual cell complexity manageable.
Solution Approach 2:
The piezoelectric unit cells employ asymmetric piezoelectric layer orientations (perpendicular to each other) rather than uniform parallel orientations. This asymmetry enables the generation of consistent electrical fields in multiple directions, maximizing voltage output from acoustic wave and vibration-induced mechanical stress.
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 corrugated piezoelectric design enhances sensitivity and robustness, enabling higher voltage tapping and reproducible behavior, while allowing for cost-effective manufacturing and integration with existing ASICs.
Implementation Method 1
Such membranes of microelectromechanical transducers can be formed at least in sections from a piezoelectric material, in which, in the case of a passive displacement of the membrane, a voltage is induced
Implementation Method 2
piezoelectric unit cells are arranged to induce consistent electrical fields and absorb mechanical stresses, allowing for higher voltage output and improved sensitivity
Implementation Method 3
The integration of corrugated piezoelectric membranes with a central inertial mass and undulated sections, where piezoelectric unit cells are arranged to induce consistent electrical fields
Data Source
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AI summary
A combined MicroElectroMechanical structure (MEMS) includes a first piezoelectric membrane having one or more first electrodes, the first piezoelectric membrane being affixed between a first holder and a second holder; and a second piezoelectric membrane having an inertial mass and one or more second electrodes, the second piezoelectric membrane being affixed between the second holder and a third holder.