TMS Coil Arrangement for Heat Distribution and Field Precision
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Solution Overview
Problem
Current TMS coil designs face challenges in translating simulated minimum-energy or loss designs into real-world devices due to high current densities and corresponding high loss power densities, leading to heating issues that can cause skin irritation or burns.
Innovation Solution
A coil arrangement comprising a first and second coil with inner and outer windings, where the outer windings are partially parallel to each other, allowing for a specific spatial magnetic field distribution that reduces power requirements and heat peaks, while being manufacturable and optimizing electrical field generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If simulation-based minimum-energy coil designs are physically realized, then energy efficiency is improved, but wire diameter must be extremely thin leading to very high losses and manufacturing difficulty
Solution Approach 1:
The coil is divided into two separate coils (first coil and second coil) with各自独立的 windings, allowing each to be manufactured with practical wire diameters while collectively achieving the desired magnetic field distribution and energy efficiency that would require extremely thin wires in a single coil design
Solution Approach 2:
The inner winding is surrounded by the outer winding in each coil, creating a nested structure where the inner winding generates the primary magnetic field and the outer winding provides shielding and field shaping, enabling practical wire dimensions while maintaining simulation-based energy efficiency
2Ease of manufacture
If maximum usable wire diameter is used, then manufacturing is easier, but local current density increases leading to high power losses and heating
Solution Approach 1:
The total current is divided between two separate coils, reducing the current density in each individual coil. This allows using thicker, easier-to-manufacture wires while maintaining acceptable power loss levels through the distributed current paths
Solution Approach 2:
The outer windings provide localized field modification and shielding, allowing the inner windings to operate at optimal current densities for their specific function, thereby reducing overall power losses while maintaining manufacturability with standard wire diameters
3Device complexity
If single large coil design is used, then simplicity is maintained, but spatial resolution and field precision are insufficient
Solution Approach 1:
The single large coil is segmented into two separate coils with distinct winding patterns, enabling independent optimization of each coil's contribution to the magnetic field. This segmentation achieves superior spatial resolution and field precision while maintaining relatively simple overall structure
Solution Approach 2:
The transition from a single-planar coil to two coils with parallel sections adds a dimensional aspect to field control, enabling more precise spatial distribution of the magnetic field through the combined contributions of both coils in three-dimensional space
4Power
If high current density is applied, then TMS effectiveness is improved, but skin irritation and burns risk increase
Solution Approach 1:
The total power delivery is segmented across two separate coils, distributing the current load and reducing the current density at any single point on the scalp. This maintains TMS effectiveness while reducing the risk of skin irritation and burns associated with concentrated high current density
Solution Approach 2:
The outer windings, which would normally be sources of additional heating and power loss, are configured to provide shielding and field shaping that directs and concentrates the effective magnetic field toward the target brain region, converting potential harmful energy dissipation into beneficial field focusing that improves effectiveness while managing heat 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
The proposed design achieves improved spatial resolution, reduced power dissipation, and enhanced comfort during TMS by distributing heat and balancing resistive losses, thereby minimizing the risk of skin burns.
Implementation Method 1
TMS uses brief, intense pulses of electric current delivered to a coil placed on the subject's head to generate an electric field in the brain via electromagnetic induction
Implementation Method 2
Magnetic fields produced by the first and second coils when provided with a current appear as the sum of the individual coils' magnetic fields
Implementation Method 3
the heat generated by the coil arrangement is distributed by the first and second coils thereby reducing local heat peaks
Data Source
AI summary
The invention relates to a coil arrangement for transcranial magnetic stimulation and a device comprising such a coil arrangement. The coil arrangement comprising a first coil having a first plurality of windings, the first plurality of windings comprising at least an inner winding and an outer winding; a second coil having a second plurality of windings, the second plurality of windings comprising at least an inner winding and an outer winding, wherein the first and second coils are arranged adjacent to each other along a first predetermined surface, wherein the outer winding surrounds at least partially the inner winding of the respective first and second coils along the first predetermined surface, wherein adjacent sections of the outer windings of the first and second coils are at least partially arranged parallel to each other.