Flexible Circuit Wire Joining With Resistance-Based Heat Control

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Solution Overview

Problem

The challenge in manufacturing catheters with flexible circuit strips is the time-consuming and costly process of establishing electrical connections between numerous wires and pads, which can damage the heat-sensitive polymer material due to repeated heating.

Innovation Solution

The solution involves monitoring resistance between a joining tool and an electrode to control the heating process, using a pulsed power supply to maintain the resistance below a threshold that prevents damage to the flexible circuit strip, and ensuring the quality of the connection by identifying a drop in resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If repeated heating is applied to establish electrical connections between wires and pads, then the electrical connection quality is improved, but the heat-sensitive polymer material of the flexible circuit strip is damaged

Engineering Contradiction:
Improveelectrical connection qualityVSAvoidpolymer material damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system monitors resistance between the joining tool and an electrode during the heating process. This resistance measurement provides real-time feedback about the temperature of the flexible circuit strip, allowing the control system to adjust heating parameters dynamically to prevent polymer damage while ensuring adequate connection quality

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The invention changes the heating parameters (temperature and duration) based on monitored resistance values. By adjusting these parameters in real-time according to the actual state of the polymer material, the system achieves optimal connection quality without exceeding the thermal tolerance of the heat-sensitive polymer

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the heating process is extended to ensure thorough electrical connection, then connection reliability is improved, but the manufacturing time and cost increase

Engineering Contradiction:
Improveelectrical connection qualityVSAvoidmanufacturing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

Real-time resistance monitoring provides feedback that indicates when the electrical connection has reached sufficient quality. This allows the heating process to be terminated as soon as the connection is adequate, preventing unnecessary extension of heating time while ensuring reliable connections

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The invention replaces time-based process control with resistance-based control. Instead of heating for a fixed duration to ensure connection quality, the system uses electrical resistance measurements to determine when connections are sufficient, significantly reducing manufacturing time while maintaining reliability

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

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 method reduces the duration and temperature of heating, preventing damage to the flexible circuit strip while ensuring a high-quality electrical connection, thereby improving the efficiency and reliability of the catheter manufacturing process.

Implementation Method 1

activating the joining tool to heat a tip of the joining tool to electrically connect the wire to the connection pad

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

monitoring, during the activating, a resistance between the joining tool and an electrode electrically connected to the connection pad, which resistance is indicative of temperature of the flexible circuit strip

Methodology Applied
Scientific EffectElectrical resistance: Electrical Resistance

Data Source

PatentEP4565016A1Automated control of an electrical connection joining process
Publication Date: 2025.06.04 BIOSENSE WEBSTER (ISRAEL) LTD
  • EP4565016A1 patent drawingFigure 1A~1B
  • EP4565016A1 patent drawingFigure 2~3A
  • EP4565016A1 patent drawingFigure 3B~4

AI summary

A method of electrically connecting a wire to a connection pad of a flexible circuit strip using a heat joining tool, wherein the flexible circuit strip includes a polymer body, a plurality of electrodes, a plurality of connection pads and a plurality of conductive traces, a trace connecting each of the plurality of electrodes to a connection pad of the plurality of connection pads, the method including: positioning the joining tool in proximity to a connection pad of the plurality of connection pads and a wire to be connected to the connection pad; activating the joining tool to heat a tip of the joining tool to electrically connect the wire to the connection pad; monitoring, during the activating, a resistance between the joining tool and an electrode electrically connected to the connection pad, which resistance indicative of temperature of the flexible circuit strip; and controlling the activating to maintain the resistance below an upper threshold associated with the flexible circuit strip reaching a damaging temperature.