Planar Coil with Non-Concentric Rings for Magnetic Tracking
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Solution Overview
Problem
Magnetic field tracking systems face inaccuracies due to distortions caused by field-distorting objects, such as metal equipment and conductive medical devices, which can lead to errors in determining the position and orientation of medical instruments during procedures.
Innovation Solution
The use of a planar coil with non-concentric rings that tilts the magnetic field's moment vector at an angle from the normal plane, combined with a conductive layer to shield the magnetic field from distortions, reduces interference and enhances tracking accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional electromagnetic sensors are used to generate magnetic fields for tracking, then position and orientation information can be obtained, but magnetic field distortions from conductive objects cause measurement inaccuracies
Solution Approach 1:
The patent employs non-concentric rings with asymmetric geometry instead of conventional symmetric coil structures. The rings have different radii and are positioned at different distances from the central axis, creating an asymmetric current distribution that generates a magnetic field with a tilted moment vector. This asymmetric configuration inherently reduces sensitivity to distortions from conductive objects while maintaining tracking accuracy.
Solution Approach 2:
The patent changes the geometric parameters of the coil structure by using non-concentric rings with varying radii and positions. Specifically, the first and second non-concentric rings have different inner and outer radii, and are arranged at different axial distances from the substrate. This parameter variation creates a magnetic field configuration that is less susceptible to distortion from conductive objects, thereby improving measurement precision.
2Object-affected harmful factors
If a planar coil with non-concentric rings is used to tilt the magnetic field moment vector, then distortion from conductive objects is reduced, but the device complexity increases
Solution Approach 1:
The patent extracts the essential function of generating a tilted magnetic field moment vector from complex three-dimensional coil assemblies and implements it using a simplified two-dimensional planar configuration with non-concentric rings. By taking out only the necessary geometric features (non-concentric arrangement with specific radius ratios) from complex coil designs, the solution reduces device complexity while maintaining the distortion-reduction benefit.
Solution Approach 2:
The patent transitions from conventional three-dimensional coil wound structures to a two-dimensional planar configuration printed on a substrate. This dimensionality change simplifies manufacturing while achieving the same functional effect of tilting the magnetic field moment vector through non-concentric ring geometry, thereby reducing device complexity.
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 configuration minimizes magnetic field distortions, improving the precision of position and orientation tracking of medical instruments by reducing interference from conductive objects, thereby enhancing the reliability of electromagnetic tracking systems.
Implementation Method 1
a planar coil coupled to the substrate, wherein the planar coil comprises non-concentric rings, wherein the non-concentric rings are configured such that a drive current applied across the non-concentric rings provides a magnetic field
Implementation Method 2
the magnetic fields generated by eddy currents in another conductive object
Data Source
AI summary
A source for inducing an electromagnetic magnetic field, comprising: a substrate, a conductive layer coupled to the substrate, and a planar coil coupled to the substrate, wherein the planar coil comprises non-concentric rings, and wherein the non-concentric rings are configured such that a drive current applied across the non-concentric rings provides a magnetic field, and wherein the magnetic field comprises a moment vector that is tilted at an angle from the normal to a plane of the planar coil. Also provided are a method of electromagnetic tracking, a method of manufacture of a planar coil, and an electromagnetic sensor.