Balloon Catheter Capacitive Sensor for High-Strain Diameter Measurement
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Solution Overview
Problem
Existing resistive strain sensors for balloon catheters suffer from drift, hysteresis, and non-linear relationships during high strain measurements, making it difficult to accurately monitor and control balloon diameter expansion during angioplasty procedures.
Innovation Solution
A capacitive sensor with planar, expandable electrodes on the balloon wall that measures diameter changes through capacitance, ensuring a simple design with linear and reproducible readings, minimizing drift and hysteresis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If resistive strain sensors are used for high strain measurements, then balloon diameter can be monitored, but the measurements suffer from drift, hysteresis, and non-linear relationships
Solution Approach 1:
The patent replaces resistive strain sensors with a capacitive sensor system that uses electrical capacitance measurements instead of resistance changes. This substitution eliminates the drift and hysteresis problems inherent in resistive sensors by using a different physical principle (capacitance) that is not affected by the same material degradation mechanisms.
Solution Approach 2:
The patent changes the measurement parameter from electrical resistance to electrical capacitance. By measuring capacitance changes rather than resistance changes, the system achieves linear and reproducible measurements without the drift and hysteresis characteristics that plague resistive sensors under high strain conditions.
2Measurement precision
If complex electrode design is used to accommodate large balloon volume increase, then high strain measurements can be achieved, but device complexity increases
Solution Approach 1:
The capacitive sensor is divided into multiple discrete capacitive elements or electrodes distributed around the balloon circumference. This segmentation allows each element to independently measure local strain while accommodating the overall balloon expansion, providing comprehensive high strain measurement capability without requiring a single complex electrode structure.
Solution Approach 2:
The patent uses capacitance measurement instead of resistance measurement, which fundamentally changes how the sensor responds to balloon expansion. Capacitive sensors naturally accommodate volume increase and high strain conditions through their measurement principle, allowing for simpler electrode designs compared to resistive sensors that would require complex compensation mechanisms.
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 capacitive sensor provides accurate, linear, and reproducible measurements of balloon diameter under high strain, enabling precise control during angioplasty by overcoming the limitations of resistive sensors.
Implementation Method 1
A capacitive sensor (4) configured to determine a diameter (D) of the balloon extends in a radial direction (R) of the balloon
Data Source
AI summary
A balloon catheter includes a balloon extending in an axial direction (z). The balloon includes an expandable balloon wall that extends around the balloon in a circumferential direction (U) and surrounds a balloon interior space of the balloon. The balloon interior space is configured to be filled with a fluid inflation medium. A capacitive sensor is configured to measure a diameter (D) extending in a radial direction (R) of the balloon. The sensor includes a capacitor having two planar and expandable electrodes arranged on the balloon wall.