pMUT Array Geometry for High-Frequency Ultrasound Imaging
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Solution Overview
Problem
Conventional ultrasound transducer arrays are limited in size and frequency capability, as they cannot produce thickness mode vibrator elements smaller than 175-200 microns capable of transmitting and receiving above 5-6 MHz due to destructive dicing processes, making it impractical for higher frequency ultrasound imaging.
Innovation Solution
Piezoelectric Micromachined Ultrasound Transducer (pMUT) arrays with predetermined geometry configured for fundamental mode vibration, allowing for smaller sizes and increased frequency capabilities, enabling transmission and reception of ultrasound beams at frequencies up to 30 MHz with improved sensitivity and reduced production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional dicing techniques are used to produce PZT thickness mode vibrator elements, then manufacturing is feasible, but the element size cannot be reduced below 175-200 microns and frequency cannot exceed 5-6 MHz
Solution Approach 1:
The patent segments the PZT material into thin films deposited on a substrate, rather than attempting to dice small elements from a bulk block. This allows individual elements to be much smaller (below 175-200 microns) while maintaining structural integrity, as the thin film approach avoids the mechanical stress and destruction inherent in dicing processes.
Solution Approach 2:
The patent replaces the mechanical dicing process with a deposition-based fabrication approach. Instead of mechanically cutting PZT blocks into small elements, the invention uses thin film deposition techniques to create piezoelectric layers, enabling smaller element sizes without compromising integrity and allowing frequencies above 5-6 MHz.
2Speed
If element size is reduced below 175-200 microns to achieve higher frequencies, then frequency capability increases, but conventional dicing processes destroy the elements
Solution Approach 1:
The patent divides the PZT material into thin film layers deposited on a substrate, enabling creation of very small elements (below 175-200 microns) that would be impossible to produce via conventional dicing. This segmentation approach allows high-frequency operation while maintaining manufacturability through deposition processes rather than mechanical cutting.
Solution Approach 2:
The patent changes the fundamental fabrication parameter from bulk material dicing to thin film deposition. This parameter change enables element sizes below 175-200 microns to be manufactured with high precision and integrity, making high-frequency ultrasound elements (above 5-6 MHz) production-feasible for the first time.
3Measurement precision
If pMUT geometry is optimized for fundamental mode vibration, then sensitivity and frequency response improve, but device design complexity increases
Solution Approach 1:
The patent optimizes specific geometric parameters of the pMUT (membrane area, thickness, cavity volume) to tune the fundamental mode vibration frequency and improve sensitivity. By systematically adjusting these parameters, the invention achieves high sensitivity and frequency response while managing design complexity through focused optimization of key geometric features.
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 pMUT arrays achieve significantly smaller sizes and increased frequency response compared to conventional arrays, enabling effective ultrasound imaging at higher frequencies with improved sensitivity and reduced noise interference, while maintaining efficient energy transmission and reception.
Implementation Method 1
Each array element comprises at least one piezoelectric layer disposed on the substrate... configured to transmit and receive at least one ultrasound beam having a bandwidth including the predetermined fundamental mode vibration
Implementation Method 2
the returned echoes and echo images can be processed to quantify tissue and blood motion and other quantities... Each array element comprises at least one piezoelectric layer disposed on the substrate... configured to transmit and receive at least one ultrasound beam
Data Source
AI summary
Piezoelectric Micromachined Ultrasound Transducer (pMUT) arrays for ultrasonic imaging, and related apparatuses, systems, and methods are disclosed. In one embodiment, an ultrasonic imaging assembly comprises a substrate and a plurality of array elements arranged on the substrate in an array. Each array element comprises at least one pMUT disposed on the substrate each having a geometry configured to accept a predetermined fundamental mode vibration. The plurality of array elements are configured to transmit and receive at least one ultrasound beam based on the predetermined fundamental mode vibration. By sizing the pMUTs to correspond to a desired fundamental mode vibration, the pMUT array has improved sensitivity, and can be produced relatively cheaply compared to conventional dicing methods.