pMUT Air-Backed Cavity Vertical Electrical Connection
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Solution Overview
Problem
The existing methods for forming electrically-conductive connections between piezoelectric micromachined ultrasonic transducers (pMUTs) and integrated circuits or flex cables are challenging, especially for 2D transducer arrays, due to the difficulty in bending flex cables to achieve the necessary 90-degree bend required for integration into small catheters or endoscopes, limiting the minimum size of the device that can be used.
Innovation Solution
A method involving a dielectric layer on a device substrate with a piezoelectric material between electrodes, where vias are filled with conductive materials and support members are used to create external connections through etching and bonding processes, allowing signal leads to extend parallel to the transducer array for direct engagement, thereby avoiding the need for severe cable bending.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If flex cables are used to connect pMUT devices in a forward-looking transducer array, then electrical connections can be established, but severe bending (about 90 degrees) is required which limits the minimum size of catheter/endoscope
Solution Approach 1:
The patent transitions from lateral/planar connections to vertical/three-dimensional connections by routing flex cables through the longitudinal axis of the catheter. Instead of bending cables 90 degrees at the catheter end, the connections are made along the length of the catheter, allowing the transducer array to be positioned forward-looking without requiring severe cable bends.
Solution Approach 2:
The patent inverts the conventional connection approach by having cables enter through the distal end of the catheter and route backward along the catheter length, rather than entering at the proximal end and bending forward. This reversal eliminates the need for 90-degree bends at the catheter tip.
2Adaptability or versatility
If more wires and flex cable assemblies are used for 2D transducer arrays, then more signal interconnections are achieved, but the difficulty of bending increases and minimum catheter size is limited
Solution Approach 1:
The patent utilizes the longitudinal dimension of the catheter to route multiple cables parallel to each other along the catheter length, rather than attempting to bundle and bend multiple cables in a compact lateral space. This three-dimensional routing approach accommodates higher cable counts for 2D arrays without increasing bending complexity.
Solution Approach 2:
The patent segments the cable management into individual cable routes, with each cable independently routed through the catheter lumen. This segmentation allows each cable to be managed separately, reducing the overall complexity of handling and bending multiple cables compared to a bundled approach.
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 scalable and efficient electrically-conductive connections for both 1D and 2D transducer arrays, allowing for greater flexibility in the size of catheters or endoscopes that can integrate these transducers without the need for complex cable bending, enhancing the usability of pMUTs in medical devices.
Implementation Method 1
the transducer device includes a piezoelectric material disposed between a first electrode and a second electrode
Implementation Method 2
The device substrate and the dielectric layer define a first via extending to the first electrode. The first via is substantially filled with a first conductive material.
Data Source
AI summary
A method and associated apparatus directed to a piezoelectric micromachined ultrasonic transducer (pMUT) defining an air-backed cavity are provided. A first via defined by a device substrate and associated dielectric layer, and extending to the first electrode, is substantially filled with a first conductive material. A support member engaged with the device substrate defines a second via extending to the first conductive material. The second via has a second conductive material disposed thereon, forms an electrically-conductive engagement with the first conductive material, and extends outwardly of the second via to be accessible externally to the support member. A connective element extends through a third via defined by a connection support substrate and is in electrically-conductive engagement with the second conductive material, wherein one of the connective element and connection support substrate is bonded to one of the support member and second conductive material by a bonding material engaged therebetween.