Rolled Flexible PCB Coils for Orthogonal Triple-Axis Sensing

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Solution Overview

Problem

Existing methods for producing orthogonal coils on flexible printed circuit boards are costly and inefficient, requiring multiple layers and complex manufacturing processes.

Innovation Solution

A flexible single-sided printed circuit board is rolled into a Swiss roll configuration, with conducting spirals and lines formed on one side and interconnected by vias to create three mutually orthogonal coils, significantly reducing production costs and complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If multiple layers are used to form orthogonal coils on flexible printed circuit boards, then the coils can be formed with proper orthogonality, but the manufacturing complexity and cost increase significantly

Engineering Contradiction:
Improvecoil orthogonalityVSAvoidmanufacturing process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent transforms the traditional multi-layer approach into a single-layer solution by rolling the flexible circuit board into a cylindrical configuration. This dimensional transformation allows coplanar conductive traces to form three-dimensional orthogonal coils when wrapped around the cylinder, eliminating the need for multiple layers while maintaining coil orthogonality.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The flexible circuit board is rolled into a cylindrical (curved) configuration, transforming flat coplanar traces into three-dimensional coils. This curvature enables the formation of orthogonal coils from a single layer, as the cylindrical geometry naturally positions traces at different angular orientations to achieve orthogonality when viewed from the center of the cylinder.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Manufacturing precision

If multiple layers are used to form orthogonal coils, then proper coil geometry is achieved, but production cost increases

Engineering Contradiction:
Improvecoil geometryVSAvoidproduction cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent combines multiple coil windings and orthogonal orientations into a single planar layer that is then rolled. Instead of manufacturing separate layers and stacking them, the invention merges all coil structures into one continuous flexible circuit board layer, simplifying the manufacturing process and reducing production costs while maintaining geometric precision.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The use of a flexible thin film (flexible circuit board) allows the circuit to be rolled into a cylindrical configuration. This flexibility enables the transformation from a flat single-layer structure to a three-dimensional multi-coil structure, achieving complex geometry without the cost of multiple rigid layers.

Inventive Principle:
Principle #30Flexible shells and thin films

3Ease of manufacture

If coplanar conductors are used on a single layer, then manufacturing is simplified, but the conductors cannot form orthogonal coils when flat

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidcoil orthogonality
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent resolves this contradiction by adding a third dimension through rolling. Coplanar conductors on a single flat layer cannot form orthogonal coils, but when the layer is rolled into a cylinder, the conductors naturally form three-dimensional orthogonal coils. This dimensional transformation maintains manufacturing simplicity while achieving the required geometric precision.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 allows for the cost-effective formation of orthogonal coils, enhancing the efficiency of magnetic field sensing and tracking systems while simplifying the manufacturing process.

Implementation Method 1

One of the methods for sensing magnetic fields is to position a coil so that it is traversed by the field. A potential induced in the coil provides a measure of the field traversing the coil.

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3340750B1Flexible printed circuit board for a triple axis sensor
Publication Date: 2024.08.07 BIOSENSE WEBSTER (ISRAEL) LTD
  • EP3340750B1 patent drawingFigure 1
  • EP3340750B1 patent drawingFigure 2A
  • EP3340750B1 patent drawingFigure 2B

AI summary

Apparatus, including a flexible insulating substrate, having a first side and a second side, rolled about an axis parallel to the substrate. The apparatus also includes a first conducting spiral that is right-handed relative to a normal to the substrate, and a second conducting spiral that is left-handed relative to the normal, formed on the first side of the substrate. The first conducting spiral has a first initial termination and a first final termination, the second conducting spiral has a second initial termination and a second final termination, the spirals have a displacement therebetween, with a preset magnitude so that when the substrate is rolled about the axis the first initial termination aligns with the second initial termination. The apparatus also has a via penetrating the substrate from the first side to the second side so as to interconnect the first initial termination and the second initial termination.