PMUT Imaging Through Discrete Reflectors for Wider Acoustic View

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Solution Overview

Problem

Existing piezoelectric micro-machined ultrasonic transducers (PMUTs) face challenges in efficiently adjusting their acoustic resonance properties to match varying frequencies and improve signal strength and field of view, particularly in applications requiring high sensitivity and omnidirectional imaging.

Innovation Solution

The PMUTs are designed to interface with an acoustic resonance cavity that has adjustable properties, such as volume and reflector positions, allowing for dynamic matching of resonant frequencies and beam spreading through a mesh or porous membrane of discrete reflectors, which can be manipulated by magnetic or piezoelectric means.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a ultrasonic transducer assembly is made sterilizable by autoclaving, then it can be reused and cost-effective, but the housing material must withstand high temperature and pressure which limits material choices and increases manufacturing complexity

Engineering Contradiction:
ImprovesterilizabilityVSAvoidhousing material requirements
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The housing is constructed from composite materials including PEEK (polyether ether ketone) and PPSU (polyphenylene sulfone) that combine high temperature resistance, autoclave sterilization capability, and acoustic transparency. These composite polymer materials allow the housing to withstand autoclaving conditions while maintaining structural integrity and ultrasonic wave transmission properties.

Inventive Principle:
Principle #40Composite materials

2Reliability

If the housing material is acoustically transparent to allow ultrasonic wave transmission, then transducer performance is improved, but the material selection is restricted and may compromise structural strength or sterilization capability

Engineering Contradiction:
Improveacoustic transmissionVSAvoidhousing strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The housing utilizes composite polymer materials such as PEEK and PPSU that possess both acoustic transparency for ultrasonic wave transmission and sufficient mechanical strength to maintain structural integrity during operation and sterilization processes.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The housing design incorporates specific geometric parameters including wall thickness, curvature radius, and surface finish that are optimized to maximize acoustic transmission while maintaining structural strength. The curved surfaces and controlled thickness profiles allow ultrasonic waves to pass through with minimal attenuation.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the housing has a smooth curved surface for acoustic optimization, then ultrasonic wave transmission is improved, but manufacturing precision requirements increase and production cost rises

Engineering Contradiction:
Improveacoustic optimizationVSAvoidsurface finish precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The housing features smooth curved surfaces with optimized radius of curvature that improve ultrasonic wave transmission by reducing scattering and reflection. The curved geometry is designed to match the acoustic requirements while being manufacturable using standard injection molding techniques with appropriate tooling.

Inventive Principle:
Principle #14Spheroidality (Curvature)

4Reliability

If the transducer assembly uses a proprietary connector design for secure coupling, then connection reliability is improved, but manufacturing complexity and production time increase

Engineering Contradiction:
Improveconnector reliabilityVSAvoidassembly speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The connector is designed as a segmented, modular component that allows for tool-free manual assembly and disassembly. The housing includes integrated connector elements that can be coupled with the transducer cartridge through simple snap-fit or bayonet-style connections, enabling quick changes without compromising connection reliability.

Inventive Principle:
Principle #1Segmentation

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 design enhances signal strength and field of view by optimizing transmission and reception across varying frequencies, enabling high-quality imaging with reduced energy consumption and improved signal processing capabilities.

Implementation Method 1

Ultrasonic transducers have been used as sterilizing devices to kill microorganisms by contact with a surface to be sterilized. The transducers generate ultrasonic vibrations that disrupt the microorganisms' cell walls, thereby killing them.

Methodology Applied
Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Data Source

PatentEP4504428B1Piezoelectric micro-machined ultrasonic transducer
Publication Date: 2026.05.06 SINTEF TTO AS
  • EP4504428B1 patent drawingFigure 1
  • EP4504428B1 patent drawingFigure 2A~2B
  • EP4504428B1 patent drawingFigure 3~4A

AI summary

A piezoelectric micro-machined ultrasonic transducer, PMUT (302), interfaces with an amorphous medium such that in use ultrasonic signals to or from the PMUT (302) pass through the amorphous medium. The amorphous medium has a number of discrete reflectors (110a, 110b, 111a, 111b) distributed therein. A method of imaging using the PMUT or an array of the PMUTs (302) includes the steps of: determining an acoustic transfer function corresponding to the effect of the discrete reflectors (110a, 110b, 111a, 111b) positioned between the PMUT or PMUT array (302) and a scene to be imaged; imaging the scene using the PMUT or PMUT array (302) by transmitting an ultrasonic signal and receiving the ultrasonic signal at the PMUT or PMUT array (302), after the ultrasonic signal has undergone one or more reflections; and processing the received ultrasonic signal to generate an image by applying the inverse of the acoustic transfer function to the received ultrasonic signals.