Dual Magnetic Sensor Layout for Large-Air-Gap Motion Detection
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Solution Overview
Problem
Miniaturized magnetic-field-based devices face challenges in generating a sufficiently strong sensor signal due to large air gaps, which limits the precision of position and movement determination, especially in applications with space restrictions where increasing the magnet size is not feasible.
Innovation Solution
A device featuring a permanent magnet that can rotate and tilt, paired with two magnetic field sensors arranged on a common substrate along a straight line parallel to the rotation axis, allowing for differential measurement of magnetic vector fields to enhance signal strength and compensate for external interference, enabling detection of rotational and tilting movements with increased air gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the air gap between the magnet and sensor is increased, then the installation space is improved, but the signal strength decreases
Solution Approach 1:
Two magnetic field sensors are combined into a single measurement system, arranged adjacent to each other on a common substrate. This merging of sensors compensates for the signal weakening caused by increased air gap, as the combined measurement from both sensors maintains sufficient measurement precision despite the larger distance from the magnet.
2Measurement precision
If a stronger magnet is used to increase signal strength, then the measurement precision is improved, but the magnet dimensions must be increased
Solution Approach 1:
Instead of increasing magnet size to improve signal strength, the patent combines two magnetic field sensors to achieve the desired measurement precision. This approach maintains compact magnet dimensions while obtaining sufficient signal strength through the combined output of adjacent sensors.
Solution Approach 2:
The patent changes the parameter of sensor arrangement by placing two sensors adjacent to each other on a common substrate, rather than relying on increasing magnet strength. This parameter change in the sensor configuration achieves improved measurement precision without increasing magnet volume.
3Reliability
If two magnetic field sensors are arranged adjacent to each other, then the signal strength is doubled, but the device complexity increases
Solution Approach 1:
Two magnetic field sensors are merged into a single functional unit mounted on a common substrate, positioned adjacent to each other. This configuration doubles the effective signal strength while keeping the device complexity manageable through integrated mounting and coordinated operation of the sensor pair.
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 significantly increases the air gap distance between the magnet and sensors to several millimeters while maintaining precise position and movement detection, overcoming the limitations of conventional devices by doubling the signal strength and compensating for temperature and interference effects.
Implementation Method 1
The magnetic field is a vector field, wherein the magnetic field lines emanating from a magnet have a magnitude and a direction. Magnetic field sensors can be sensitive in a specific preferred direction
Implementation Method 2
Common magnetic field sensors can take the form of Hall sensors or magnetoresistive sensors, for example. Hall sensors can, for example, have one or more Hall elements
Implementation Method 3
Common magnetic field sensors can take the form of Hall sensors or magnetoresistive sensors, for example
Data Source
AI summary
A device for the magnetic-field-based determination of rotational and/or tilting movements, including a permanent magnet which is rotatable on both sides about a rotation axis and is tiltable on both sides along a tilting axis extending orthogonally to the rotation axis, two magnetic field sensors which are each configured to measure magnetic vector fields in at least two dimensions, namely at least parallel to the rotation axis and parallel to the tilting axis of the permanent magnet, wherein the magnetic field sensors are arranged on a common substrate and are arranged next to one another along a straight line parallel to the rotation axis of the permanent magnet, and wherein the magnetic field sensors are spaced apart from the outer surface of the permanent magnet.