Capacitance-Based Joining Tool Height Control for Flexible Circuit Pads
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Solution Overview
Problem
The existing methods for establishing electrical connections to flexible circuit strips in catheters are time-consuming and costly due to the small size and high density of the connection pads, which requires precise positioning of the joining tool to avoid damage and ensure high-quality connections.
Innovation Solution
An automated process using capacitance measurements to accurately position a joining tool relative to the pads on a flexible circuit strip, allowing for rapid and precise soldering or welding of wires to the pads, thereby reducing the risk of damage and improving connection quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If manual methods are used to establish electrical connections to small, high-density pads, then positioning precision can be maintained, but the process becomes time-consuming and costly
Solution Approach 1:
The patent replaces manual mechanical positioning with an automated system that uses capacitance sensing to detect pad locations and control joining tool height. The capacitance sensor detects changes in electrical field capacitance as the joining tool approaches the pad, enabling precise automated positioning without human intervention, thus resolving the contradiction between productivity and positioning precision.
Solution Approach 2:
The system uses the pad's own electrical properties (capacitance) to guide the joining tool to the correct position. The capacitance sensor measures the electrical field changes caused by the pad itself, allowing the system to self-position without external reference markers or complex mechanical alignment mechanisms, thereby achieving both speed and precision.
2Reliability
If the joining tool is positioned closer to the pad to ensure good electrical contact, then connection quality improves, but the risk of damaging the pad increases
Solution Approach 1:
The patent implements a feedback control system where the capacitance sensor continuously monitors the distance between the joining tool and the pad. As the tool approaches, the capacitance changes provide real-time feedback to the control system, which adjusts the tool position to maintain optimal contact pressure without exceeding the threshold that would cause pad damage, thus resolving the contradiction between connection quality and damage risk.
Solution Approach 2:
The system changes the control parameter from fixed mechanical position to dynamic capacitance-based positioning. By monitoring capacitance changes, the system can adapt the joining tool's position and contact force in real-time, ensuring sufficient electrical contact while preventing excessive force that would damage the pad, thereby balancing connection quality with damage prevention.
3Quantity of substance
If the pad size is reduced to increase density, then more connections can be made in the same area, but the difficulty of positioning and connecting increases
Solution Approach 1:
The patent replaces visual or mechanical detection methods with capacitance-based detection. The capacitance sensor can detect the electrical field changes caused by each small pad, enabling automatic identification and positioning even when pads are densely packed and difficult to distinguish mechanically or visually, thus resolving the contradiction between pad density and positioning difficulty.
Solution Approach 2:
The capacitance sensing mechanism serves multiple functions simultaneously: it detects pad location, measures pad size, determines optimal joining distance, and provides feedback for controlled contact. This multi-functional approach simplifies the system's ability to handle high-density pads compared to specialized mechanical detection methods, resolving the contradiction between quantity and detection 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
The automated process significantly reduces the time and cost associated with establishing electrical connections by enabling precise and efficient positioning of the joining tool, resulting in high-quality, mechanically strong, and electrically conductive connections.
Implementation Method 1
monitoring a capacitance between the joining tool and the flexible circuit strip; controllably lowering the joining tool toward the pad until the capacitance reaches a predefined capacitance threshold
Data Source
AI summary
A method of electrically connecting a wire to a connection pad of a flexible circuit strip using a joining tool, which method comprising: receiving the flexible circuit strip on a support surface, wherein the flexible circuit strip includes a plurality of electrodes, a plurality of connection pads and conductive traces connecting each of the plurality of electrodes to a connection pad of the plurality of connection pads; positioning a joining tool over a first connection pad of the flexible circuit strip; monitoring a first capacitance between said joining tool and a conductive layer positioned under the connection pads, wherein said conductive layer is sized, shaped, and positioned to extend over a footprint of said plurality of connection pads; controllably lowering said joining tool toward said first connection pad until the first capacitance reaches a first predefined capacitance threshold, wherein said first predefined capacitance threshold defines a first height of said joining tool with respect to said flexible circuit strip; monitoring a second capacitance between a first electrode electrically connected to said first connection pad and said joining tool; controllably lowering said joining tool from said first height until said second capacitance reaches a second predefined capacitance threshold, wherein said second predefined capacitance threshold defines a second height of said joining tool with respect to said first connection pad; and activating said joining tool to electrically connect said first connection pad to said wire.