Atomic Diffusion Bonding for High Frequency Ultrasonic Transducers
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Solution Overview
Problem
Current high-frequency ultrasonic transducers face challenges in achieving reliable and consistent bonding of delay lines to piezoelectric elements, leading to issues with sensitivity, bandwidth, and mechanical stability, especially at high frequencies.
Innovation Solution
The implementation of an atomic diffusion bond between the delay line and the piezoelectric element, facilitated by interposing metal conductive layers, allows for efficient acoustic energy coupling and robust mechanical bonding, overcoming the limitations of traditional adhesive-based bonding methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If adhesive-based bonding is used to join delay line to piezoelectric element, then ease of manufacture is improved, but reliability and mechanical stability deteriorate at high frequencies
Solution Approach 1:
A thin metal layer is introduced as an intermediary between the delay line and piezoelectric element. This metal layer serves dual purposes: it enables atomic diffusion bonding for reliable mechanical attachment while also functioning as a conductive layer for electrical connection, eliminating the need for separate adhesive and electrical connection layers.
Solution Approach 2:
The patent replaces adhesive-based mechanical bonding with atomic diffusion bonding. This substitution eliminates the reliability issues associated with adhesives at high frequencies while maintaining ease of manufacture through a streamlined single-layer solution that combines structural and electrical functions.
2Ease of manufacture
If adhesive layer is used for bonding, then ease of manufacture is improved, but acoustic energy coupling deteriorates
Solution Approach 1:
The patent changes the material parameter of the bonding layer from adhesive (soft, compliant material) to thin metal layer (rigid, acoustically transparent material). This parameter change improves acoustic energy coupling between the delay line and piezoelectric element while maintaining ease of manufacture through the integrated bonding and conduction function.
3Device complexity
If traditional bonding methods are used, then manufacturing process is simple, but manufacturing precision and consistency deteriorate
Solution Approach 1:
The patent merges the bonding function and electrical connection function into a single thin metal layer. This consolidation simplifies the manufacturing process by eliminating multiple bonding and wiring steps while simultaneously improving manufacturing precision and consistency through reduced process variability and better interfacial contact.
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 enhances the transducer's performance by improving sensitivity, bandwidth, and mechanical stability, while also enabling cost-effective and consistent large-scale production of high-frequency ultrasonic transducers.
Implementation Method 1
The delay line and the piezoelectric element are joined by an atomic diffusion bond so that ultrasonic waves may be coupled from the piezoelectric element into the delay line or from the delay line into the piezoelectric element.
Implementation Method 2
The ultrasonic stimulus waves can be either compressive or shear waves... an ultrasonic stimulus wave generator such as a piezoelectric element
Implementation Method 3
the delay line includes a first and second section which forms an interface which is substantially perpendicular to the first direction; and the second section including a surface for coupling with a material to be investigated
Data Source
AI summary
An ultrasonic transducer that includes a delay line, a piezoelectric element, and a metal conductive layer between the delay line and the piezoelectric element. The delay line and the piezoelectric element are acoustically joined with an atomic diffusion bond to facilitate coupling ultrasonic waves from the piezoelectric element into the delay line or from the delay line into the piezoelectric element.