High Temperature Array Transducer with Porous Backing
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Solution Overview
Problem
Conventional ultrasonic array transducers are limited to operating below 80°C due to material degradation and acoustic impedance mismatch at elevated temperatures, leading to failure and increased noise in high-temperature applications.
Innovation Solution
The solution involves a method of manufacturing an array transducer arrangement with a piezoelectric layer and a backing layer, where primary kerfs are cut through the piezoelectric layer and into the backing layer to create electrically isolated piezoelectric elements, and a porous region in the backing layer to scatter and absorb sound, eliminating the need for epoxy and ensuring acoustic impedance matching across the temperature range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If epoxy matrix medium is used to separate piezoelectric elements, then the transducer can be manufactured with conventional materials, but the acoustic insulation deteriorates at elevated temperatures causing distortion and increased cross-talk
Solution Approach 1:
The patent changes the material parameter from epoxy (polymer) to air or vacuum (gas/vacuum state), fundamentally altering the acoustic insulation medium. This parameter change eliminates the temperature-dependent degradation of epoxy while maintaining the necessary acoustic isolation between elements, thereby resolving the contradiction between manufacturability and high-temperature reliability.
Solution Approach 2:
The patent creates a composite structure combining piezoelectric ceramic elements with air/vacuum spacing, eliminating the need for traditional epoxy matrix. This composite approach maintains acoustic insulation performance at high temperatures while simplifying the overall structure and improving manufacturability through the 'dice and fill' method with air/vacuum filling.
2Temperature
If piezoelectric material is heated above Curie temperature, then the operating temperature range is expanded, but the material becomes depolarized causing transducer failure
Solution Approach 1:
The patent selects piezoelectric materials with high Curie temperatures (e.g., PZT-5A with Curie point at 450°C) to fundamentally expand the operating temperature range. This material parameter selection allows the transducer to operate reliably at temperatures where conventional PZT materials would fail, directly resolving the contradiction between temperature range and property stability.
3Temperature
If backing layer material is exposed to high temperatures, then the thermal buffer capacity is increased, but the acoustic coupling between transducer components deteriorates over time
Solution Approach 1:
The patent changes the backing layer material from conventional polymers to metals or ceramics with high-temperature stability. This material parameter change allows the backing layer to withstand high temperatures without degrading the acoustic coupling, thereby maintaining both thermal buffer capacity and coupling stability over time.
4Ease of manufacture
If epoxy resin is used as acoustic insulation, then the transducer can be assembled with conventional materials, but the acoustic impedance mismatch increases at elevated temperatures causing element failure
Solution Approach 1:
The patent changes the acoustic insulation medium from epoxy (which has temperature-dependent acoustic impedance) to air or vacuum (which have stable acoustic impedance at high temperatures). This parameter change eliminates the acoustic impedance mismatch problem while maintaining ease of manufacture through the dice and fill method.
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 configuration allows for prolonged high-temperature operation above 80°C, maintaining acoustic coupling and reducing noise, thereby enhancing the reliability and performance of ultrasonic transducers in high-temperature environments.
Implementation Method 1
Ultrasonic array transducers conventionally include an ordered series or arrangement of many elements (an array) of a piezoelectric material, usually a lead zirconate titanate (PZT) ceramic
Implementation Method 2
a porous region in the backing layer to scatter and absorb sound
Data Source
AI summary
A method of manufacturing an array transducer arrangement, an array transducer arrangement for use in a high temperature environment, a method of manufacturing an array transducer arrangement for use in a high temperature environment, apparatus for selectively emitting ultrasonic waves in a high temperature environment, a method of producing a porous backing layer for a high temperature array transducer arrangement, and a backing layer for an array transducer arrangement are disclosed. The method of manufacturing an array transducer arrangement comprises: providing a piezoelectric layer; arranging a backing layer on a first face of the piezoelectric layer; and cutting a plurality of primary kerfs through the piezoelectric layer and into the backing layer to provide a plurality of piezoelectric elements; whereby the primary kerfs define a pitch of the plurality of piezoelectric elements.