Flexible PCB Electromagnet Coils for Precise 3D Field Geometry
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Solution Overview
Problem
Traditional methods for forming magnetic coils, such as manual winding and single-layer flexible printed circuit boards (PCBs), result in imprecise and non-repeatable wire placement, limiting the strength and shape of electromagnets, particularly in applications like Wien filters for electron microscopes.
Innovation Solution
The use of multiple flexible PCBs bent into specific shapes with conductive coiled traces, where adjacent PCBs are positioned to conform and connect electrically, allowing for the creation of strong magnetic fields with precise geometry, including sharp corners, while minimizing human error.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If manual winding is used to form magnetic coils, then flexibility in shaping is achieved, but manufacturing precision and repeatability deteriorate
Solution Approach 1:
The patent replaces manual mechanical winding with automated PCB fabrication processes. Conductive traces are deposited using photolithography and etching techniques, eliminating manual wire placement while maintaining precise geometric control through photoresist patterns and automated deposition systems.
Solution Approach 2:
The patent changes the physical state and form of the conductive element from discrete wire to deposited trace material. This allows precise control of trace width, thickness, and geometry through deposition parameters, while the flexible PCB substrate maintains shaping capability through its inherent flexibility and conformability.
2Strength
If additional layers are added to flexible PCB to increase coil strength, then magnetic field strength improves, but PCB rigidity increases preventing desired bending
Solution Approach 1:
The patent implements nested PCB structures where multiple flexible PCB layers are stacked and bonded together, each containing conductive coil traces. The PCBs are conformally arranged with one PCB nested within or adjacent to another, allowing the assembly to achieve desired three-dimensional coil geometries while maintaining overall flexibility through the thin-layer construction.
Solution Approach 2:
The patent transitions from planar two-dimensional coil traces to three-dimensional coil structures by stacking multiple PCB layers in the vertical dimension. This enables complex spatial coil geometries and increased turn density without requiring individual traces to leave the PCB surface, maintaining flexibility while achieving strong magnetic fields.
3Adaptability or versatility
If single-layer flexible PCB is used, then PCB flexibility is maintained, but the number of coil turns is limited reducing magnetic field strength
Solution Approach 1:
The patent stacks multiple flexible PCB layers containing coil traces in a nested arrangement, where each PCB contributes additional turns to the overall coil structure. This multi-layer nesting achieves high turn counts and strong magnetic fields while preserving the flexibility of individual thin PCB layers.
Solution Approach 2:
The patent utilizes the vertical dimension by stacking PCB layers to increase coil turn density. Instead of attempting to fit all turns in a single plane, the coil structure extends through multiple layers, achieving higher effective turns and stronger magnetic fields without compromising PCB flexibility in the lateral dimensions.
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 approach enables the fabrication of electromagnets with reproducible, strong magnetic fields and precise shapes, enhancing the performance and reliability of devices like Wien filters by overcoming limitations of traditional methods.
Implementation Method 1
Electromagnet coils made from flexible circuits
Data Source
AI summary
A method of fabricating an electromagnet includes obtaining a first flexible PCB that includes one or more first conductive coiled traces and obtaining a second flexible PCB that includes one or more second conductive coiled traces. The first flexible PCB is bent into a shape having at least one curve or corner. With the first flexible PCB having been bent into the shape, the second flexible PCB is then bent into the shape: the second flexible PCB is positioned adjacent to the first flexible PCB to conform with the first flexible PCB. The second flexible PCB may substantially surround the first flexible PCB. An electrostatic deflector may be disposed concentrically with the first and second flexible PCBs.