Flexible Substrate Sensor Traces for Medical Guidewires

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing elongate medical devices face challenges in reliably connecting sensors and cables due to the fragility of leads, which can break at solder joints, and the complexity and cost of fabrication, especially when small diameters and precise positioning are required for medical applications like catheters and guidewires.

Innovation Solution

The solution involves depositing electrically-conductive traces on a flexible inner tube within the medical device, using techniques like chemical vapor deposition and electroplating, and coupling sensors with these traces through conductive adhesives, allowing for robust and reliable electrical connectivity along the device's length.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If soldering is used to connect sensor leads to cable leads, then electrical connection is achieved, but the leads and sensors are damaged during fabrication and assembly due to their delicacy and small diameter

Engineering Contradiction:
Improveconnection reliabilityVSAvoidfabrication difficulty
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

A flexible substrate serves as an intermediary component between the sensor leads and cable leads. The substrate receives conductor traces through deposition processes and provides bonding pads for connecting both sensor and cable leads, eliminating the need for direct soldering between fragile leads. This mediator approach allows robust electrical connections without exposing delicate components to damaging soldering processes.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical soldering process with a combination of material deposition (chemical vapor deposition, electroplating) and adhesive bonding. Instead of using heat and mechanical pressure of soldering, the invention uses conformal deposition of conductive materials and bonding pads that can be attached with adhesives, thereby avoiding thermal and mechanical damage to fragile sensor leads.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Volume of moving object

If leads are made with small diameter (e.g., 10μm) to fit medical devices, then device size is reduced, but the leads become fragile and break at or near the solder joint during testing

Engineering Contradiction:
Improvedevice sizeVSAvoidlead strength
Core Design Contradiction:
Volume of moving objectVSStrength

Solution Approach 1:

The patent merges the sensor leads and cable leads onto a common flexible substrate with integrated conductor traces. Instead of having separate fragile leads that connect at a vulnerable solder joint, the electrical pathway is continuous through the substrate's conductor traces, combining the function of both leads into a single robust structure that distributes mechanical stress along the entire connection path.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention uses a flexible substrate as a thin film structure that provides both electrical connectivity and mechanical flexibility. This flexible substrate can accommodate bending and deformation without breaking the electrical connections, replacing rigid wire leads with a flexible conductor layer that maintains electrical continuity under mechanical stress.

Inventive Principle:
Principle #30Flexible shells and thin films

3Volume of moving object

If sensors are made with small dimensions to fit into typical medical devices, then device compatibility is improved, but fabrication becomes complicated and occupies undesirable radial space

Engineering Contradiction:
Improvesensor sizeVSAvoidfabrication complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The flexible substrate serves multiple functions simultaneously: it provides mechanical support for the sensor, creates electrical connections through conductor traces, provides bonding pads for lead attachment, and acts as a flexible circuit board. This multi-functional approach eliminates the need for separate components and complex assembly procedures, reducing fabrication complexity while maintaining small sensor dimensions.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 reliability and durability of sensor connections, reduces fabrication complexity and costs, and maintains the device's functionality while withstanding stress and bending stresses, such as during prolapse procedures.

Implementation Method 1

deforming the flexible substrate so as to move opposed edges of the flexible substrate closer to one another

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

depositing electrically-conductive traces on a flexible inner tube within the medical device, using techniques like chemical vapor deposition and electroplating

Methodology Applied
Scientific EffectChemical vapor deposition: Chemical Vapour Deposition

Implementation Method 3

depositing electrically-conductive traces on a flexible inner tube within the medical device, using techniques like chemical vapor deposition and electroplating

Methodology Applied
Scientific EffectElectroplating: Electroplating

Implementation Method 4

coupling sensors with these traces through conductive adhesives

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3082588B8Elongate medical devices incorporating a flexible substrate, a sensor, and electrically-conductive traces
Publication Date: 2018.12.19 ST JUDE MEDICAL INT HLDG SARL

AI summary

An elongate medical device may include a corewire (188) defining a longitudinal axis, a sensor (176), and a flexible substrate (162) wrapped around the sensor so as to form a tube. The tube is disposed about the longitudinal axis. The elongate body may be a corewire, in an embodiment, and the corewire may extend through the tube. The sensor may comprise a coil, in an embodiment, and the corewire may extend through the coil. The elongate medical device may be a guidewire, in an embodiment.