Dual Frequency Ultrasound Transducer Arrays
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Solution Overview
Problem
Current acoustic transducer technologies face challenges in efficiently transmitting and receiving acoustic pulses across multiple frequency bands from a common radiation surface, particularly in medical ultrasound imaging and other applications, where simultaneous transmission of low and high-frequency pulses with minimal phase sliding is required to achieve optimal imaging and treatment outcomes.
Innovation Solution
The design of transducer arrays with a common radiation surface that allows for the transmission and reception of multiple frequency bands, including high-frequency (HF), first lower-frequency (LF1), and second lower-frequency (LF2) bands, using piezoelectric layers and isolation sections to achieve impedance matching and minimize relative position sliding, with the HF piezo-layer in front and LF1 piezo-layer behind, and additional layers for further frequency bands if needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate transducers are used for different frequency bands, then frequency band coverage is improved, but device size and complexity increase
Solution Approach 1:
The patent combines multiple piezoelectric layers with different resonance frequencies (first piezoelectric layer for low frequency band, second piezoelectric layer for high frequency band) into a single integrated transducer structure with a common radiation surface, allowing simultaneous operation across multiple frequency bands without requiring separate transducer assemblies
Solution Approach 2:
The transducer structure is designed to perform multiple functions across different frequency bands using a single device - the first piezoelectric layer handles low frequency applications (e.g., deep tissue imaging, treatment) while the second piezoelectric layer handles high frequency applications (e.g., superficial imaging), making the transducer universally applicable to diverse ultrasound needs
2Adaptability or versatility
If piezoelectric layers are stacked for multi-frequency operation, then frequency band transmission is improved, but phase sliding control becomes difficult
Solution Approach 1:
The patent introduces an isolation section positioned between the first and second piezoelectric layers that acts as an intermediary element. This isolation section includes impedance matching layers specifically designed to control acoustic coupling between the layers, thereby managing phase sliding effects and enabling independent optimization of each frequency band's performance
Solution Approach 2:
The patent employs impedance matching layers with specifically engineered acoustic impedance values to control the interaction between piezoelectric layers. By adjusting the impedance parameters of the isolation section, the system can optimize phase relationships and minimize unwanted phase sliding while maintaining efficient energy transmission across both frequency bands
3Loss of energy
If impedance matching layers are added, then energy transmission is improved, but transducer size increases
Solution Approach 1:
The patent integrates impedance matching layers within the stacked piezoelectric structure itself, nesting the matching layers between the piezoelectric layers rather than adding them as external components. This nested arrangement allows the matching layers to perform their energy optimization function while occupying space already allocated for the multi-layer piezoelectric construction, thereby minimizing overall transducer volume increase
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 solution enables efficient multi-band operation with minimal overlap and diffraction, allowing for improved imaging and treatment capabilities across varying depth ranges and applications, such as medical ultrasound, non-destructive testing, and SONAR, by maintaining adequate amplitude and phase alignment of pulses across different frequency bands.
Implementation Method 1
utilizing piezoelectric layers and impedance matching sections to achieve phase sliding
Implementation Method 2
an isolation section for acoustic isolation of vibrations in the band of the neighbor section to the front
Data Source
AI summary
An acoustic probe transmits/receives acoustic pulses with frequencies both in a high frequency (HF), and a selectable amount of lower frequency (LF1, LF2, . . . , LFn, . . . ) bands. The radiation surfaces of at least two of the multiple frequency bands have a common region. The arrays and elements can be of a general type such as annular arrays, phased or switched arrays, linear arrays with division in both azimuth and elevation direction, like a 1.5D, a 1.75D and a full 2D array, or curved arrays. The element division, array type, and array aperture sizes for the different bands can also be different.