Ultrasound Probe Interposer Assembly for Reliable Flex-to-PCB Coupling
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Solution Overview
Problem
Coupling flexible circuits in transesophageal and catheter ultrasound probes is difficult and unreliable, leading to poor reliability and high maintenance costs due to soldered connections that can crack or break, requiring replacement of both circuits if one malfunctions.
Innovation Solution
An interposer is used to electrically couple the flexible circuit to a printed circuit board, secured by a bolster plate without fasteners passing through, maintaining electrical connections and reducing damage during assembly and disassembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If surface soldering is used to couple flexible circuits, then electrical connections are established, but the connections have poor reliability and can crack or break when deformed
Solution Approach 1:
The patent introduces an interposer as an intermediary component between the flexible circuit and the transducer array. This interposer provides a robust mechanical and electrical coupling interface that eliminates the need for surface soldering on flexible substrates. The interposer includes contact pads that electrically connect to the flexible circuit through reliable methods (such as through-hole plating or rigid substrate bonding) while providing a stable mounting surface for the transducer array, thereby preventing crack propagation and connection failure during deformation.
Solution Approach 2:
The patent segments the coupling system into distinct functional components: the flexible circuit, the interposer, and the transducer array mounting structure. By dividing the coupling function across these separate components, each can be optimized for its specific function - the flexible circuit maintains flexibility, the interposer provides rigid electrical connections, and the mounting structure secures the transducer array. This segmentation allows reliable electrical connections without requiring the flexible circuit itself to bear mechanical stress.
2Adaptability or versatility
If flexible circuits are deformed beyond threshold or repeatedly, then the circuits can be positioned flexibly, but the conductive traces crack or break
Solution Approach 1:
The interposer serves as a mediator that decouples the flexibility requirement from the electrical connection integrity. The flexible circuit can deform as needed for positioning, while the interposer maintains stable electrical connections to the transducer array. The interposer's rigid structure prevents trace cracking by absorbing mechanical stress away from the conductive traces.
Solution Approach 2:
The patent designs the interposer and mounting structure to provide mechanical support and stress distribution before deformation occurs. The interposer's rigid substrate and the mounting structure's securing mechanism preemptively protect the flexible circuit traces from excessive stress during subsequent deformations, allowing the circuit to be deformed within safe thresholds without cracking.
3Ease of manufacture
If soldered flexible circuits are used, then electrical connections are made, but repair requires replacement of both circuits and components
Solution Approach 1:
The patent segments the electrical connection system into replaceable modules: the flexible circuit, the interposer, and the transducer array. This modular design allows individual components to be replaced independently without affecting other parts. If the flexible circuit fails, only that circuit needs replacement, not the entire assembly, significantly reducing repair complexity and cost.
Solution Approach 2:
The interposer acts as a permanent intermediary that remains in the assembly while flexible circuits can be replaced. The interposer provides stable mounting points and electrical interfaces that survive component replacements. This allows the system to be repaired by replacing only the faulty flexible circuit rather than de-soldering and replacing the entire assembled unit.
4Strength
If fasteners pass through components to secure the bolster plate, then the plate is securely attached, but electrical connections and components may be damaged
Solution Approach 1:
The patent extracts the fastening function from the electrical connection path. The bolster plate is secured to the housing or mounting structure using fasteners that attach to external mounting holes or tabs, rather than passing through the interposer and flexible circuit components. This separation allows strong mechanical attachment while protecting the electrical components from fastener-induced damage.
Solution Approach 2:
The patent moves the fastening operation to a different spatial dimension - attaching the bolster plate to the housing or mounting structure rather than to the interposer or circuit board. This dimensional separation allows the plate to be securely fastened without the fasteners interfering with or damaging the electrical connections and sensitive components.
Data Source
AI summary
Systems, methods, and apparatuses for coupling a flexible circuit to a printed circuit board (PCB) with an interposer in an ultrasound probe are disclosed. A bolster plate configured to compress the PCB, interposer, and flexible circuit against a transducer mount is disclosed. A method of coupling a bolster plate to a transducer mount with fasteners is disclosed. Fasteners that do not pass through the PCB, interposer, and flexible circuit are disclosed.