Ultrasound Transducer Electrode Patterning and Bondline Control

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current methods for manufacturing high-frequency ultrasound transducers face challenges in creating precise electrode patterns and thin bondlines, which can result in voids, mechanical coupling issues, and increased force requirements, affecting the transducer's performance.

Innovation Solution

The method involves using a composite dielectric material with a matrix and particulate material, where the matrix is laser ablated at a lower fluence than the particulate to increase surface area, and a conductive metal is deposited, followed by resist application and etching to create patterned electrodes. Additionally, spacers are used to control the thickness of matching layers and kerf slots in the transducer stack, allowing for precise alignment and bonding of components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional methods are used to create electrode patterns and bondlines in high-frequency ultrasound transducers, then manufacturing is simpler, but voids form and mechanical coupling issues occur, reducing reliability

Engineering Contradiction:
Improvetransducer performanceVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The method performs preliminary actions by depositing the composite dielectric material with particulate reinforcement before bonding, and by using spacers to pre-establish the precise bondline thickness. This preliminary preparation prevents void formation and ensures proper mechanical coupling during the subsequent bonding process, thereby improving reliability without significantly increasing manufacturing complexity

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent employs a composite dielectric material containing particulate reinforcement (such as silica or alumina particles) embedded in a polymer matrix. This composite material provides both electrical insulation and mechanical strength, enabling thin bondlines to be formed without voids while maintaining structural integrity during assembly

Inventive Principle:
Principle #40Composite materials

2Use of energy by moving object

If thin bondlines are used in ultrasound transducers, then acoustic energy transmission is optimized, but excessive force is required and voids form

Engineering Contradiction:
Improveacoustic energy transmissionVSAvoidbonding force
Core Design Contradiction:
Use of energy by moving objectVSForce

Solution Approach 1:

The composite dielectric material with particulate reinforcement provides enhanced mechanical strength and reduced compliance compared to pure polymer materials. This allows the formation of thin bondlines (optimized for acoustic energy transmission) without requiring excessive bonding force, as the particulate reinforcement bears the mechanical load

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the material parameters by incorporating particles with specific acoustic impedance and mechanical properties into the dielectric material. This modification allows the bondline to maintain thin dimensions for optimal acoustic energy transmission while the altered material composition reduces the force required for bonding and prevents void formation

Inventive Principle:
Principle #35Parameter changes

3Reliability

If precise electrode patterns are created in high-frequency transducers, then transducer performance is enhanced, but manufacturing complexity increases

Engineering Contradiction:
Improvetransducer performanceVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The method uses spacers to pre-establish the precise bondline thickness and electrode pattern geometry before the bonding process. This preliminary positioning ensures that when the thin bondline is formed, the electrodes are already correctly aligned, achieving precise electrode patterns without requiring complex post-bonding adjustment procedures

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The spacers act as intermediary elements that temporarily hold the components in the correct position during assembly. These spacers define the precise electrode patterns and bondline thickness, and are removed after bonding, thereby achieving high precision electrode patterns without significantly increasing the overall manufacturing process 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

This approach enables the production of high-frequency ultrasound transducers with improved electrode precision, reduced voids, and minimized mechanical coupling, enhancing the transducer's performance and reliability by maintaining a thin bondline without excessive force, thus optimizing the acoustic energy transmission.

Implementation Method 1

laser ablated at a lower fluence than the particulate material; laser ablating at least a portion of the composite dielectric material to remove matrix material and increase the surface area of the composite dielectric material

Methodology Applied
Scientific EffectLaser ablation: Laser Ablation

Data Source

PatentEP3309823B1Ultrasound transducers
Publication Date: 2020.02.12 FUJIFILM SONOSITE INC
  • EP3309823B1 patent drawingFigure 1~3
  • EP3309823B1 patent drawingFigure 4~6
  • EP3309823B1 patent drawingFigure 7~10

AI summary

The invention features methods for the manufacture of electrical components such as ultrasound transducers. In particular, the invention provides methods of patterning electrodes, e.g., in the connection of an ultrasound transducer to an electrical circuit; methods of depositing metal on surfaces; and methods of making integrated matching layers for an ultrasound transducer. The invention also features ultrasound transducers produced by the methods described herein.