Buried Cavity Transducer Assembly for Ultrasonic Imaging
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Solution Overview
Problem
Conventional transducer assemblies have a limited number of piezoelectric actuators due to spacing constraints, which restricts the increase in image quality and fidelity while avoiding flexural modes outside the operating bandwidth.
Innovation Solution
The transducer assembly includes a substrate with buried cavities and a plurality of piezoelectric actuators on the surface, where each actuator overlaps a cavity, allowing for a closer spacing and increased number of actuators, thereby enhancing image fidelity and operating bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of piezoelectric actuators is increased to improve image quality and fidelity, then image fidelity is improved, but flexural modes occur outside the operating bandwidth
Solution Approach 1:
The patent introduces a vertical dimension by embedding cavities within the substrate at a depth of 5-20 micrometers below the surface. This three-dimensional configuration allows piezoelectric actuators to be positioned closer together horizontally (reducing pitch) while the buried cavities provide structural support that prevents flexural modes, effectively resolving the contradiction between increasing actuator density and maintaining operating bandwidth.
Solution Approach 2:
The patent embeds cavities within the substrate structure, creating a nested configuration where the cavities are contained within the substrate volume. This nesting approach allows the cavities to provide mechanical support and prevent flexural modes while occupying minimal space, enabling closer actuator spacing without compromising the substrate's structural integrity or operating bandwidth.
2Quantity of substance
If the spacing between adjacent piezoelectric actuators is minimized to increase the number of actuators, then the number of actuators is increased, but flexural modes are generated outside the operating bandwidth
Solution Approach 1:
By moving the support structures (cavities) from the surface level to a depth of 5-20 micrometers within the substrate, the patent creates separation between the actuator array plane and the support structures. This vertical separation allows actuators to be spaced more closely in the horizontal plane without the support structures interfering with actuator operation, thereby increasing actuator count while preventing flexural modes.
Solution Approach 2:
The patent provides localized structural support at specific points within the substrate where cavities are embedded. This localized support approach targets specific regions to prevent flexural modes only where needed, allowing other regions to have minimized actuator spacing. The cavities act as local support elements that maintain structural integrity without constraining the overall actuator density.
3Quantity of substance
If the dimension of walls between cavities is reduced to accommodate more actuators, then the number of actuators is increased, but manufacturing precision becomes more difficult
Solution Approach 1:
The patent specifies a wall dimension parameter range of 5-20 micrometers, which represents an optimized compromise between accommodating high actuator density and maintaining manufacturability. This parameter specification transforms the manufacturing challenge into a controlled design parameter, allowing standard semiconductor fabrication processes to achieve the required precision without excessive difficulty.
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 a higher number of piezoelectric actuators in the same space, increasing the fidelity and detail of ultrasonic images while maintaining the operating bandwidth, thus providing improved image quality without unwanted flexure modes.
Implementation Method 1
Conventional transducer die and assemblies generally include an array of piezoelectric actuators that is present within the conventional transducer die and assemblies to generate and propagate a plurality of waves (e.g., acoustic waves such as ultrasonic waves)
Data Source
AI summary
The present disclosure is directed to transducer assemblies or device in which one or more buried cavities are present within a substrate and define or form one or more membranes along a surface of the substrate. One or more piezoelectric actuators are formed on the one or more membranes and the one or more piezoelectric actuators drive the membranes at an operating frequency with an operating bandwidth of the transducer assemblies. Each of the one or more membranes is anchored at respective portions to a main body portion of the substrate to provide robust and strong anchoring of each of the one or more membranes to push unwanted flexure modes outside the operating bandwidth of the transducer assemblies.