Ultrasound Transducer Variable Thickness Dematching Layer

Solution Overview

Problem

Conventional ultrasound transducers face challenges in achieving a broad bandwidth due to the difficulty and expense of manufacturing piezoelectric materials with multiple thicknesses, which are required to optimize frequency responses.

Innovation Solution

Incorporating a dematching layer with varying thickness, made from materials with higher acoustic impedance than the acoustic layer, to enhance the bandwidth of the ultrasound transducer, allowing for a thinner acoustic layer that maintains resonant frequency and improves electrical impedance matching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If piezoelectric material is machined to have multiple thicknesses to achieve broader bandwidth, then bandwidth is improved, but manufacturing difficulty and cost increase significantly

Engineering Contradiction:

ImprovebandwidthVSAvoidmanufacturing difficulty

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The invention divides the bandwidth enhancement function into two separate components: the piezoelectric acoustic layer maintains a single uniform thickness for ease of manufacturing, while a separate dematching layer is introduced with variable thickness to provide the bandwidth extension. This segmentation allows each layer to be optimized independently - the piezoelectric layer for electrical and mechanical properties, and the dematching layer for acoustic impedance management across multiple frequency bands.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The dematching layer serves as an intermediary component between the piezoelectric acoustic layer and the backing layer. By positioning this layer with higher acoustic impedance between the acoustic layer and backing, it creates acoustic impedance transitions that enable broader bandwidth operation without requiring the piezoelectric material itself to be manufactured with multiple thicknesses.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If piezoelectric material is machined to have multiple thicknesses to achieve broader bandwidth, then bandwidth is improved, but manufacturing cost increases

Engineering Contradiction:

ImprovebandwidthVSAvoidmanufacturing cost

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The invention divides the bandwidth enhancement function into two separate components: the piezoelectric acoustic layer maintains a single uniform thickness for ease of manufacturing, while a separate dematching layer is introduced with variable thickness to provide the bandwidth extension. This segmentation allows each layer to be optimized independently - the piezoelectric layer for electrical and mechanical properties, and the dematching layer for acoustic impedance management across multiple frequency bands.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention replaces the expensive and difficult-to-manufacture multi-thickness piezoelectric structure with a more economical approach: a standard uniform-thickness piezoelectric layer combined with a dematching layer made from materials such as tungsten carbide or other high-acoustic-impedance materials that are more cost-effective and easier to manufacture with variable thickness profiles.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Speed

If acoustic layer thickness is increased to achieve lower resonant frequency, then lower frequency response is improved, but electrical impedance matching deteriorates

Engineering Contradiction:

Improveresonant frequencyVSAvoidelectrical impedance match

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The dematching layer serves as an intermediary component between the piezoelectric acoustic layer and the backing layer. By positioning this layer with higher acoustic impedance between the acoustic layer and backing, it creates acoustic impedance transitions that enable broader bandwidth operation without requiring the piezoelectric material itself to be manufactured with multiple thicknesses.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 approach results in a transducer with increased bandwidth, specifically demonstrating 18.4% more 6 dB bandwidth and 11% more 20 dB bandwidth compared to transducers with constant dematching layer thickness, while being more cost-effective and easier to manufacture than machining piezoelectric materials with multiple thicknesses.

Implementation Method 1

The dematching layer typically includes a material with a higher acoustic impedance than the acoustic layer

Methodology Applied

Scientific EffectAcoustic impedance mismatch: Reflection

Implementation Method 2

piezoelectric materials, such as lead zirconate titanate (PZT)

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP3086885B1Ultrasound transducer with a variable thickness dematching layer

Publication Date: 2024.04.17 GENERAL ELECTRIC CO

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AI summary

An ultrasound transducer and an ultrasound imaging system including an acoustic layer with a plurality of transducer elements and a dematching layer coupled to the acoustic layer. The dematching layer has an acoustic impedance greater than the acoustic layer and the dematching layer has a thickness that varies in order to alter a bandwidth of the ultrasound probe.