MEMS Membrane Transducer with Piezoelectric Cantilever Damping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Microelectromechanical membrane transducers face challenges in damping oscillations when switching between transmitting and receiving modes, particularly in air, leading to noise and increased complexity in signal processing due to residual pressure waves, which require individual calibration and testing, resulting in unsustainable costs.
Innovation Solution
Incorporating a cantilever damper with a damper piezoelectric actuator that bends towards the membrane to increase the damping coefficient, synchronizing membrane-actuation and damper-actuation signals to rapidly suppress oscillations, and using a manufacturing process that forms a semiconductor-based structure with a membrane and piezoelectric actuators for efficient damping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the damping factor is kept low to obtain higher sensitivity, then the sensitivity of the transducer is improved, but the oscillations of the membrane continue for a longer time causing noise and increasing the blind area
Solution Approach 1:
The patent applies a piezoelectric actuator that can dynamically adjust the damping characteristics of the membrane. The actuator is activated only during specific time periods (immediately after pulse transmission and before receiving mode), allowing the system to have low damping during normal operation for sensitivity, and high damping during transition periods to suppress oscillations rapidly.
Solution Approach 2:
The piezoelectric actuator is activated in periodic intervals - specifically during the transition from transmitting to receiving mode. This periodic activation applies damping forces only when needed, allowing the membrane to maintain low damping (high sensitivity) during normal operation while rapidly suppressing oscillations during mode transitions.
2Loss of time
If active suppression with detection of oscillations and application of driving signals in phase opposition is used, then the damping time is reduced, but individual calibration and testing of each transducer is required increasing costs
Solution Approach 1:
The patent uses a piezoelectric actuator that can be driven by the same driving device that controls the piezoelectric plate, eliminating the need for separate detection and calibration systems. The actuator responds directly to control signals from the existing driving device, making the system self-sufficient and avoiding individual calibration requirements.
Solution Approach 2:
The driving device is designed to control both the piezoelectric plate (for transmission) and the piezoelectric actuator (for damping). This multi-functionality allows the same device to perform multiple roles, eliminating the need for separate calibration circuits and reducing manufacturing complexity and costs.
3Object-affected harmful factors
If filtering techniques during post-processing are used to eliminate effects of tails of pressure waves, then the noise is reduced, but the complexity of the signal processing increases
Solution Approach 1:
The patent applies damping forces to the membrane immediately after pulse transmission, before the receiving mode begins. This preliminary action suppresses oscillations and eliminates the tails of pressure waves before they can interfere with the received signals, removing the need for complex post-processing filtering techniques.
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 solution effectively reduces the damping time of membrane oscillations, minimizing noise and simplifying signal processing by actively controlling the damping process, thereby reducing the need for extensive calibration and testing, and improving the operational efficiency of microelectromechanical membrane transducers.
Implementation Method 1
a damper piezoelectric actuator (10), arranged on the cantilever damper (7) and configured so as to bend the cantilever damper (7) towards the membrane (5) in response to an electrical actuation signal (SD)
Implementation Method 2
The piezoelectric plate converts the oscillations of the membrane into a transduction signal, which is detected and amplified by the driving device
Data Source
AI summary
A microelectromechanical membrane transducer includes: a supporting structure; a cavity formed in the supporting structure; a membrane coupled to the supporting structure so as to cover the cavity on one side; a cantilever damper, which is fixed to the supporting structure around the perimeter of the membrane and extends towards the inside of the membrane at a distance from the membrane; and a damper piezoelectric actuator set on the cantilever damper and configured so as to bend the cantilever damper towards the membrane in response to an electrical actuation signal.