Ultrasound Transducer Redistribution Layer for Side Lobe Reduction
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Solution Overview
Problem
Conventional ultrasound transducers face challenges in real-time volume scanning due to insufficient mechanical motion speed and beamforming channel limitations, leading to imaging artifacts from 'pixelation' errors and energy concentration in side lobes, which degrade contrast resolution.
Innovation Solution
A multi-dimensional transducer array with aperiodic shifts in acoustic element distribution and a layered structure of switches is used to form a one-dimensional aperture, reducing side lobes by interconnecting elements into macro elements with irregular edges and finer pitches, allowing for electronic rotation and real-time volumetric imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a two-dimensional transducer array is used for volume scanning, then volume scanning capability is achieved, but the number of beamforming channels greatly increases
Solution Approach 1:
The two-dimensional array is segmented into multiple one-dimensional subarrays that can be electronically switched and reconfigured. Instead of using all elements simultaneously as a 2D array, the system divides the aperture into several 1D subarrays that are activated sequentially, reducing the number of active beamforming channels while maintaining volume scanning capability through electronic rotation of the aperture.
Solution Approach 2:
The system dynamically reconfigures the aperture by electronically switching between different one-dimensional subarrays and rotating their orientation angles. This dynamic reconfiguration allows the same physical array to function as multiple different aperture geometries, enabling volume scanning with fewer simultaneous beamforming channels required.
2Device complexity
If a mechanically rotated one-dimensional transducer is used for volume scanning, then the number of beamforming channels is reduced, but the mechanical motion is insufficiently rapid for real-time volume scanning
Solution Approach 1:
The patent replaces the mechanical rotation mechanism with an electronic switching system. Instead of physically rotating the transducer elements, the system uses electronic switches to rapidly reconfigure which elements are active and how they are connected, achieving aperture rotation at electronic speeds that are sufficient for real-time volume scanning.
Solution Approach 2:
The system achieves dynamic aperture rotation through electronic switching rather than mechanical movement. The switches can change the aperture configuration and rotation angle instantaneously, providing the speed required for real-time imaging while maintaining the reduced channel count benefit of 1D subarrays.
3Productivity
If switches with high performance are used to allow beamformation in real-time volume scanning, then real-time scanning is achieved, but the on resistance requirements for the switches become more stringent
Solution Approach 1:
By segmenting the aperture into one-dimensional subarrays, the patent reduces the number of switches required in each signal path. Each subarray has its own dedicated switches, and not all switches need to operate simultaneously at full capacity, thereby reducing the on-resistance burden on individual switches while maintaining real-time scanning capability.
4Adaptability or versatility
If a one-dimensional aperture is fitted on a multi-dimensional array with periodic cell structure, then electronic rotation is achieved, but pixelation errors and side lobe concentration occur
Solution Approach 1:
The patent introduces aperiodic shifts in the positioning of acoustic elements within the periodic grid structure. This asymmetric perturbation of the otherwise regular element distribution prevents the formation of periodic side lobes and reduces pixelation artifacts, while the elements still maintain their overall grid-based organization for efficient electronic switching and rotation.
Data Source
AI summary
Medical diagnostic ultrasound imaging is performed with a multi-dimensional transducer array and an imaging system for planar scanning. The elements of the array may be distributed on a periodic grid with aperiodic shifts in position. When a one-dimensional array is formed on the array, the aperiodic shifts better distribute acoustic energies, reducing peaks in side lobes. Using a layered structure of switches underneath the acoustic elements, side lobes may be further reduced. The switches are used for interconnecting elements to form macro elements of the one-dimensional aperture on the multi-dimensional array. The switches are distributed on a grid corresponding to the desired imaging frequency. The acoustic elements are distributed with a finer pitch. The finer pitch allows formation of the macro elements for the one-dimensional aperture where the edges of the macro elements have fewer or no periodic patterns.