Dual and multiple membrane micromachined ultrasound transducers
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Solution Overview
Problem
Existing MEMS ultrasound transducers, such as cMUTs and pMUTs, require improvements in acoustic power and directivity, especially at high frequencies.
Innovation Solution
A micromachined ultrasonic transducer (MUT) design featuring multiple resonant cavities and electrodes, with specific geometric configurations and piezoelectric layer couplings, enhances acoustic power and directivity, particularly at frequencies above 5 MHz.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional piezoelectric transducers are used, then reliable ultrasound signal generation is achieved, but the transducer size is large and bulk manufacturing is difficult
Solution Approach 1:
The patent replaces traditional piezoelectric mechanical transducers with MEMS-based capacitive micromachined ultrasound transducers (cMUTs). This substitution enables miniaturization and facilitates bulk manufacturing through semiconductor fabrication processes while maintaining ultrasound signal generation capability through electrostatic actuation of thin membranes
Solution Approach 2:
The patent employs thin flexible membranes as the transducer element in cMUT devices. These thin films are deposited using standard semiconductor processing techniques, enabling scalable bulk manufacturing. The flexible membrane structure allows for miniaturization while maintaining the necessary mechanical properties for ultrasound generation and reception
2Ease of manufacture
If MEMS ultrasound transducers are used, then smaller size and easier bulk manufacturing are achieved, but acoustic power and directivity at high frequencies need improvement
Solution Approach 1:
The patent segments the membrane into multiple independent or coupled elements within a single device. This segmentation allows for constructive interference of acoustic waves, enhancing directivity and acoustic power at high frequencies. The segmented structure can be configured in various geometric arrangements to optimize beamforming and focal properties
Solution Approach 2:
The patent combines multiple membrane elements and electrode structures into an integrated MUT device with shared resonant cavities. This merging of components enables cooperative acoustic emission that enhances high-frequency power and directivity while maintaining compact size and manufacturing simplicity
3Ease of manufacture
If MEMS ultrasound transducers are used, then smaller size and easier bulk manufacturing are achieved, but directivity at high frequencies needs improvement
Solution Approach 1:
The patent employs asymmetric configurations of resonant cavities and membrane elements to control acoustic radiation patterns. By strategically positioning cavities with different geometries and orientations, the device achieves improved directivity at high frequencies while maintaining compatibility with standard manufacturing processes
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 MUT design achieves higher acoustic power and improved directivity, enabling more effective ultrasound imaging and manipulation at higher frequencies.
Implementation Method 1
the secondary first electrode is coupled to the primary first electrode by a first portion of the one or more piezoelectric layer portions
Implementation Method 2
a substrate having a first resonant cavity and a second resonant cavity
Data Source
AI summary
Provided herein are micromachined ultrasonic transducers as well as imaging devices and assemblies comprising micromachined ultrasonic transducers (MUTs). The MUTs described herein have a plurality of membranes so as to improve acoustic power at higher frequencies.