Capacitive Pressure Sensor With Dummy Cell For Intraluminal Guidewires
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Solution Overview
Problem
Current capacitive sensors for assessing blood vessels face challenges such as non-uniformities in manufacturing, especially with capacitive micromachined ultrasound transducers (CMUTs), leading to unpredictable behavior and difficulty in accurately measuring pressure and flow velocity within blood vessels, which hinders effective treatment of heart disease.
Innovation Solution
A capacitive pressure sensor with two active cells and one dummy cell is designed for intraluminal guidewires and catheters, where the active cells are isolated from adverse forces, allowing them to measure external pressure within blood vessels while the dummy cell does not provide electrical signals, enabling accurate pressure and flow velocity measurements without interference from device deformation or navigation forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If capacitive micromachined ultrasound transducers (CMUTs) are used for pressure sensing, then manufacturing complexity increases due to non-uniformities in membrane behavior, but measurement precision is required for accurate blood vessel assessment
Solution Approach 1:
The patent applies local quality by creating distinct regions within the sensor array: active cells at the periphery that are exposed to fluid pressure for sensing, and a central region that is isolated from fluid exposure. This spatial differentiation allows each region to serve its specific function optimally - the active cells measure pressure while the central region remains unaffected by fluid forces, thereby achieving accurate pressure measurements despite manufacturing variations in membrane uniformity
2Measurement precision
If the sensor is exposed to fluid pressure for measurement, then measurement precision improves, but the sensor becomes susceptible to adverse forces from device deformation during navigation
Solution Approach 1:
The sensor is segmented into multiple independent capacitive cells arranged in an array. The active cells at the periphery are exposed to fluid pressure for measurement, while the central cell(s) are isolated from fluid exposure. This segmentation allows the active cells to measure pressure accurately while the central cells serve as references that are not affected by fluid forces or device deformation, enabling compensation for adverse forces
Solution Approach 2:
The central cells act as intermediary reference elements that are not directly exposed to fluid pressure. These reference cells provide a baseline measurement that is unaffected by fluid forces or device deformation, allowing the system to distinguish between pressure changes due to fluid dynamics and those caused by device deformation during navigation
3Adaptability or versatility
If active cells are exposed to fluid for pressure measurement, then measurement capability is enabled, but device complexity increases due to the need for selective exposure and force isolation
Solution Approach 1:
The sensor array serves multiple functions: the active peripheral cells perform pressure measurement while the central cells provide reference measurements and can also be used for compensation calculations. This multi-functionality is achieved within a single integrated sensor structure, reducing the need for separate reference sensors and simplifying the overall device architecture despite the sophisticated measurement capability
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 design ensures accurate measurement of blood vessel pressure and flow velocity, providing reliable data for diagnosing and treating heart disease by minimizing the impact of external forces on the sensor's operation, thus improving the precision of pressure sensing within blood vessels.
Implementation Method 1
a capacitive pressure sensor with two active cells and one dummy cell... The two active cells electrically communicate with other components of the capacitive pressure sensor and are used to measure pressure
Data Source
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AI summary
A capacitive pressure sensor for a pressure-sensing guidewire or catheter includes a substrate; a first active cell formed in the substrate; a second active cell formed in the substrate, wherein the first active cell and the second active cell are electrically active to generate electrical signals representative of an external pressure; and an optional dummy cell formed in the substrate, wherein the dummy cell is electrically inactive such that no electrical signal representative of the external pressure is generated. An intraluminal pressure-sensing device and a system are also provided.