Ferrite Powder Coil Probe for Sub-150 Micron Navigation
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Solution Overview
Problem
Conventional navigable probes with diameters of 1 mm or more are limited in accessing small body parts such as lung extremities and brain blood vessels due to the difficulty in producing small enough magnetic cores for navigation coils.
Innovation Solution
A probe apparatus with a shaft and a tube containing separate ferrite powder granules, where the tube is fixed to the shaft and a coil is placed around it, using a method that involves heat shrinking or capillary action to introduce the granules into a thin tube, which is then inserted into the coil, enhancing magnetic permeability and signal amplitude.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional solid magnetic cores are used in navigation coils, then the probe diameter must be 1 mm or more to accommodate the core, but this prevents access to small body parts such as lung extremities and brain blood vessels
Solution Approach 1:
The patent replaces solid magnetic cores with ferrite powder granules that create a porous magnetic material structure. This allows the magnetic core to be compressed into extremely small dimensions (less than 150 microns) while maintaining sufficient magnetic permeability for navigation coil operation, enabling access to small body parts that were previously inaccessible
Solution Approach 2:
The patent uses composite ferrite powder granules as the magnetic core material. These granules are suspended in a liquid medium and then compressed into the coil form, creating a composite structure that combines the magnetic properties of ferrite with the structural support of the compression matrix, achieving both small size and functional performance
2Volume of moving object
If the probe diameter is reduced to less than 150 microns, then access to small body parts is enabled, but producing small enough magnetic cores becomes extremely difficult
Solution Approach 1:
The patent employs a liquid suspension medium to carry ferrite powder granules into the compressed form. The liquid acts as a carrier that facilitates the introduction and distribution of fine magnetic particles into the coil structure, making the manufacturing process feasible for sub-150-micron probes
Solution Approach 2:
The patent changes the physical state and form of the magnetic material from solid blocks to fine powder granules suspended in liquid. This parameter change allows the magnetic core to be processed and introduced into extremely small coil structures that would be impossible to manufacture with conventional solid cores
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
Enables the creation of probes with diameters less than 150 microns, allowing navigation in smaller body parts by increasing the magnetic field sensitivity and amplitude, facilitating precise position and orientation tracking within the body.
Implementation Method 1
The tube contains separate powder granules of a ferrite... increasing the magnetic field sensitivity and amplitude
Implementation Method 2
A magnetic field sensor within the distal end of the probe generates electrical signals in response to these magnetic fields
Implementation Method 3
which is then inserted into the coil, enhancing magnetic permeability and signal amplitude
Data Source
AI summary
In one embodiment, a probe apparatus includes a shaft having a distal end, a tube containing separate powder granules of a ferrite, the tube being fixed to the distal end of the shaft, a coil disposed around the tube, and electrical wires connected to the coil so as to read out a signal generated across the coil due to an externally-applied magnetic field.