MRI Magnet Assembly With Gap Magnet for Field Homogeneity
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Solution Overview
Problem
Existing magnetic measurement devices using permanent magnets face challenges in achieving a homogeneous and stable magnetic field while minimizing device size, weight, and cost, which limits mobility and applicability in hospital and industrial settings.
Innovation Solution
A magnetic field device comprising a first and second ferromagnetic element with a third magnet positioned between them, allowing translation, and additional magnets to enhance magnetic field homogeneity and stability, reducing the need for additional coils and increasing the magnetic field strength within a measurement gap.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic field compensation is performed using a measurement value from a magnetometer, then the position measurement accuracy is improved, but the device complexity increases due to requiring additional sensors and calibration procedures
Solution Approach 1:
The patent extracts and removes permanent magnets from the environment around the mobile device. By taking out the magnetic sources (permanent magnets) that cause interference, the system eliminates the need for complex magnetic field compensation using additional magnetometers, thereby reducing device complexity while maintaining measurement accuracy
Solution Approach 2:
The patent introduces a magnetic shield as an intermediary element between the permanent magnets and the mobile device. This shield blocks or attenuates the magnetic field from the permanent magnets, allowing the device to obtain accurate position measurements without requiring complex compensation mechanisms
2Measurement precision
If permanent magnets are used for positioning, then the measurement precision is improved, but the reliability deteriorates due to magnetic field interference from other permanent magnets
Solution Approach 1:
The system extracts information about permanent magnet locations from environmental data (maps, databases) rather than relying on detecting magnetic fields in real-time. This approach eliminates interference from other permanent magnets since the system uses pre-known locations, maintaining both precision and reliability
Solution Approach 2:
The patent performs preliminary action by pre-storing location information of permanent magnets in databases or maps before the actual positioning operation. This preliminary documentation of magnet locations allows the device to calculate position accurately without being affected by magnetic field interference from other magnets during measurement
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 solution provides a substantially homogeneous and uniform magnetic field with reduced device weight and size, enhancing mobility and applicability in MRI and NMR devices by increasing magnetic field strength and reducing fringe fields.
Implementation Method 1
obtain a measurement of the magnetic field vector using a magnetometer
Implementation Method 2
The processor is configured to compensate for interference from permanent magnets by obtaining location information about one or more permanent magnets in the environment
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
A magnetic field device, with a first magnet, a first ferromagnetic element positioned adjacent to the first magnet, a second magnet, a second ferromagnetic element positioned adjacent to the second magnet and relative to the first ferromagnetic element to create a gap between the first ferromagnetic element and the second ferromagnetic element, and a third magnet positioned between the first ferromagnetic element and the second ferromagnetic element and within the gap.