Asymmetric Magnet Ring Array for Uniform Fields With Lower Weight
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Solution Overview
Problem
Existing magnet designs for applications like MRI systems face challenges in achieving strong and uniform magnetic fields while being lightweight, due to the trade-off between weight, field uniformity, and the size of the volume achieving that uniformity.
Innovation Solution
The development of a magnet array comprising multiple magnet rings with rotational symmetry and finite magnetization components along azimuthal and longitudinal-radial planes, arranged with reflectional asymmetry and optionally including theta magnetic rings, to generate a strong and uniform magnetic field with minimized fringe fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional permanent magnet assemblies are used to generate strong and uniform magnetic fields, then field uniformity is improved, but weight increases
Solution Approach 1:
The patent applies asymmetry by configuring magnet rings with non-uniform spacing and/or non-uniform magnetization strengths. Specifically, the distance between adjacent magnet rings varies along the longitudinal axis, and/or the magnetization strength of each magnet ring is differently adjusted. This asymmetric configuration enables the generation of a uniform magnetic field within the imaging volume while reducing the total amount of magnetic material required, thereby decreasing the overall weight of the magnet assembly compared to traditional symmetric designs.
2Weight of stationary object
If magnet array size is reduced to decrease weight, then weight is improved, but the volume achieving uniform field decreases
Solution Approach 1:
The patent applies local quality by optimizing the magnetic field contribution of each individual magnet ring according to its specific position within the array. Each magnet ring is assigned a tailored magnetization strength and spacing relative to adjacent rings, creating a non-uniform local configuration that collectively produces a uniform magnetic field across the entire imaging volume. This localized optimization allows the system to maintain a large uniform field volume while using less total magnetic material, thereby reducing weight.
3Weight of stationary object
If asymmetric magnet ring configuration is used to reduce weight, then weight is improved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the magnet assembly into multiple discrete magnet rings arranged along the longitudinal axis. Each magnet ring functions as an independent segment that can be individually configured with specific spacing and magnetization strength. This segmented approach simplifies the overall design process by breaking down the complex asymmetric configuration into manageable units, facilitating easier manufacturing, assembly, and adjustment while achieving weight reduction through optimized material distribution.
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 enables the creation of lightweight magnet arrays that generate magnetic fields with high uniformity inside a defined inner volume, while minimizing the fringe field outside the array, thus addressing the limitations of existing designs.
Implementation Method 1
The multiple magnet rings configured to jointly generate a magnetic field along a direction parallel to the longitudinal axis
Data Source
AI summary
A magnet array (700) includes multiple magnet rings (711-720) and a frame. The multiple magnet rings are positioned along a longitudinal axis and coaxially with the longitudinal axis, wherein at least one (712, 713, 719) of the magnet rings possesses rotational symmetry and has both a finite component of magnetization along an azimuthal (θ) coordinate, and a finite magnetization in a longitudinal-radial plane. The multiple magnet rings configured to jointly generate a magnetic field along a direction parallel to the longitudinal axis. The frame is configured to fixedly hold the multiple magnet rings in place.