Segmented Ultrasound Transducer Backing for Reverberation Suppression
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Solution Overview
Problem
Ultrasonic transducers face challenges with secondary signals and reverberations due to insufficient acoustic energy attenuation in the backing layer, particularly in compact designs like catheters, which affect image quality and axial resolution.
Innovation Solution
A segmented backing surface is introduced, where at least a portion of the surface is divided into levels with spatial offsets, causing destructive interference and reducing the amplitude of secondary signals through temporal spreading and phase differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a thin backing layer is used to reduce transducer size, then the transducer dimensions are reduced, but acoustic energy is not sufficiently attenuated causing secondary signals and reverberations
Solution Approach 1:
The backing layer is divided into multiple segments with different acoustic properties (different acoustic impedances, densities, or thicknesses). This segmentation creates internal interfaces that scatter and attenuate acoustic energy, preventing coherent reflections from the bottom surface while maintaining a thin overall backing structure.
Solution Approach 2:
Different regions of the backing layer are assigned different local properties (varying acoustic impedance, density, or thickness) to optimize attenuation at specific locations. This allows targeted management of acoustic energy paths while keeping the overall backing thin.
2Loss of energy
If scatterers are introduced into the backing to increase attenuation, then acoustic energy attenuation is improved, but the transducer complexity increases
Solution Approach 1:
Instead of introducing discrete scatterers, the backing is segmented into regions with different acoustic properties. This achieves similar attenuation effects through macroscopic structural variation rather than microscopic scatterer addition, reducing fabrication complexity.
Solution Approach 2:
The acoustic properties (impedance, density, thickness) of the backing regions are systematically varied to optimize attenuation. This parameter-based approach provides controlled attenuation without the complexity of introducing foreign scatterer materials.
3Object-generated harmful factors
If a thick backing layer is used to attenuate acoustic energy, then secondary signals are reduced, but the transducer volume increases
Solution Approach 1:
The backing is divided into multiple thin segments with varying properties rather than using a single thick layer. This creates multiple attenuation interfaces within a compact thickness, achieving the secondary signal suppression of a thick backing without the volume penalty.
Solution Approach 2:
The backing consists of composite structures with multiple materials or regions having different acoustic properties. This composite approach provides enhanced attenuation per unit thickness, enabling thin overall backing while maintaining effective suppression of reflected acoustic energy.
4Object-generated harmful factors
If the backing surface is made segmented with spatial offsets, then destructive interference reduces secondary signal amplitude, but the manufacturing precision requirements increase
Solution Approach 1:
The backing surface is segmented into discrete regions with controlled spatial offsets. These offsets create the necessary path length differences for destructive interference while maintaining manufacturable tolerance ranges through careful design of the offset dimensions.
Solution Approach 2:
The spatial offset parameters are optimized to achieve destructive interference at the operating frequency while accommodating manufacturing tolerances. By tuning the offset distances and segment geometries, the design achieves robust interference-based attenuation without excessive precision requirements.
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 segmented backing effectively suppresses secondary signals, improving axial resolution and image quality by reducing the amplitude and duration of reverberations, even in constrained transducer designs.
Implementation Method 1
The levels may be spatially offset so that acoustic reflections from the segmented surface are spread out in time, thereby decreasing the net amplitude of the internally reflected waves as they interact with the piezoelectric layer. Adjacent (neighbouring) levels may be spatially offset by a longitudinal distance equaling approximately an odd number multiple of a quarter of an operational wavelength of the transducer, so that destructive interference occurs from acoustic waves reflected from adjacent levels.
Data Source
AI summary
Methods and devices are provided for suppressing reverberations within an ultrasound transducer with a backing whereby the backing may not sufficiently attenuate the acoustic energy by means of acoustic absorption and scattering alone. At least a portion of a surface of the backing is segmented into a plurality of levels defined by surface segments. The levels may be are spatially offset so that acoustic reflections from the segmented surface are spread out in time, thereby decreasing the net amplitude of the internally reflected waves as they interact with the piezoelectric layer. Adjacent (neighboring) levels may be spatially offset by a longitudinal distance equaling approximately an odd number multiple of a quarter of an operational wavelength of the transducer, so that destructive interference occurs from acoustic waves reflected from adjacent levels. Various example configurations of segmented surfaces are described, and methods for selecting a profile of a segmented surface are provided.