Ultrasonic Transducer Membrane Bandwidth via Asymmetric Control

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Solution Overview

Problem

Existing membrane-based ultrasonic transducers have limited bandwidth and performance due to resonance-based efficiency, which affects imaging resolution and other applications.

Innovation Solution

The use of a control element to induce displacement asymmetry in the membrane of ultrasonic piezoelectric transducers, enhancing bandwidth by adjusting membrane motion through passive or active means such as fluid pockets, electrostatic charges, or multiple piezoelectric layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If resonance based ultrasonic sources/receivers are used to boost transmit and/or receive efficiency, then efficiency is improved, but bandwidth is limited

Engineering Contradiction:
Improvetransmit and/or receive efficiencyVSAvoidbandwidth
Core Design Contradiction:
PowerVSAdaptability or versatility

Solution Approach 1:

The patent applies asymmetry by introducing a control element that creates asymmetric displacement of the membrane. The control element is positioned to affect only one side of the membrane, creating intentional geometric and functional asymmetry. This asymmetry enables the membrane to be driven off-resonance while maintaining efficiency, thereby expanding bandwidth without sacrificing power transmission capability

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent implements dynamics by making the membrane displacement asymmetric through active control. The control element dynamically adjusts the membrane position during operation, allowing the system to adapt its resonance characteristics in real-time. This dynamic control enables bandwidth expansion while preserving the efficiency benefits of resonance-based operation

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If a control element is added to induce displacement asymmetry, then bandwidth is improved, but device complexity increases

Engineering Contradiction:
Improveeffective bandwidthVSAvoidtransducer structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent uses a flexible membrane as the core component, which inherently provides the necessary compliance and motion control. The control element interacts with this flexible structure to induce asymmetric displacement, leveraging the membrane's natural properties rather than requiring complex rigid mechanisms. This approach expands bandwidth while minimizing the added complexity by working with而非 against the flexible nature of the transducer

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The control element acts as an intermediary between the drive signal and the membrane. Rather than directly controlling the entire membrane or requiring complex multi-element arrays, the control element provides a simple mediating mechanism that induces the desired asymmetric displacement. This intermediary approach achieves bandwidth expansion with minimal structural complexity

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

The solution significantly increases the effective bandwidth of ultrasonic transducers, allowing for improved performance and efficiency across a broader frequency range.

Implementation Method 1

An ultrasonic piezoelectric transducer comprises a first membrane (10) configured to vibrate in a direction (Z) transverse to a plane (XY) of the first membrane (10)... a piezoelectric layer (10p) coupled to an electronic circuit (30) for receiving electrical signals (E1) causing the first vibration (V1)

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

the control element (C) comprises an electrostatic device configured to generate electrostatic charges on a surface of the first membrane (10), and on another opposing surface adjacent the first membrane (10)

Methodology Applied
Scientific EffectElectrostatic effect: Electrostatics

Data Source

PatentEP4051441B1Membrane transducer with improved bandwidth
Publication Date: 2025.12.03 NEDERLANDSE ORG VOOR TOEGEPAST NATUURWETENSCHAPPELIJK ONDERZOEK TNO
  • EP4051441B1 patent drawingFigure 1A~1B
  • EP4051441B1 patent drawingFigure 2A~2B
  • EP4051441B1 patent drawingFigure 3A~3C

AI summary

An effective bandwidth in a membrane based ultrasonic transducer is improved by a control element (C). The control element (C) is disposed on a first side (10a) of a first membrane (10) of the transducer to increase or decrease a displacement amplitude of the first membrane (10) towards the first side (10a) and/or the opposite, second side (10b). This induces a displacement asymmetry (Za<>Zb) in a motion of the first membrane (10) during a first vibration (V1) of the first membrane (10) to the first side (10a) compared to the second side (10b). The displacement asymmetry may result in improved bandwidth.