3D Magnetic Field Sensor Using Magnetoresistive Bridge Circuits
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Solution Overview
Problem
Current magnetic field sensors with Hall sensors have limited spatial and temporal resolution, restricted field of view, and are hindered by parasitic effects such as temperature variations, making them inadequate for high-resolution three-dimensional magnetic field detection.
Innovation Solution
A 3D magnetic field sensor system utilizing three magnetoresistive sensor element arrangements in bridge circuits, arranged on a substrate to achieve high spatial and temporal resolution, with each sensor element detecting magnetic field components along linearly independent axes, and a matrix configuration for enhanced field detection capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Hall sensors are used for magnetic field detection, then the sensor can detect magnetic flux density, but the spatial resolution is limited to about 100 μm and temporal resolution is limited to around 1 s
Solution Approach 1:
The patent changes the fundamental detection parameter from Hall effect (voltage output proportional to magnetic field) to magnetoresistive effect (resistance change proportional to magnetic field). This parameter change enables both higher spatial resolution (10 μm vs 100 μm) and higher temporal resolution (nanosecond range vs 1 second) while maintaining magnetic field detection capability
Solution Approach 2:
The patent substitutes the Hall sensor measurement system with a magnetoresistive sensor system. This substitution replaces the voltage-based detection mechanism with a resistance-based detection mechanism, enabling significantly improved spatial and temporal resolution through different physical detection principles
2Measurement precision
If Hall sensors are miniaturized to improve spatial resolution, then smaller sensor size is achieved, but parasitic effects such as temperature variations become more significant
Solution Approach 1:
The patent converts the harmful parasitic temperature effects into beneficial compensation signals. By arranging magnetoresistive sensor elements in bridge circuits, the temperature-induced resistance changes appear as common-mode signals that can be differential subtracted, turning the harmful thermal drift into a useful reference for compensation
Solution Approach 2:
The bridge circuit acts as an intermediary structure that separates the useful magnetic field signal from the parasitic temperature signal. The bridge configuration allows temperature effects to be transmitted equally to all arms while magnetic field effects create differential imbalances, enabling selective signal extraction
3Area of stationary object
If the sensor array size is increased to expand the field of view, then larger detection area is achieved, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent segments the large sensor array into multiple smaller sensor elements that can be independently manufactured and then combined. This segmentation allows standard semiconductor manufacturing processes to produce uniform sensor units that are subsequently assembled into larger arrays, reducing overall manufacturing complexity while achieving large field of view
Solution Approach 2:
The patent merges multiple small magnetoresistive sensor elements into a coordinated array system. By combining individually manufactured sensor units with integrated readout circuits into a unified large-scale array, the system achieves both large field of view and manufacturing efficiency through modular assembly
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 system enables high spatial resolution down to 10 μm and temporal resolution in the nanosecond range, effectively compensating for parasitic effects and providing a comprehensive three-dimensional magnetic field map with improved sensitivity and reduced interference.
Implementation Method 1
Each of the magnetoresistive sensor element arrays is arranged as a bridge circuit with a plurality of magnetoresistive sensor elements
Data Source
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AI summary
The invention relates to a 3D magnetic field sensor for detecting three spatial magnetic field components in a reference region, said sensor being usuable in a magnetic field camera for example. The sensor has a first magnetoresistive sensor element arrangement, a second magnetoresistive sensor element arrangement, and a third magnetoresistive sensor element arrangement. The first magnetoresistive sensor element arrangement is designed to detect a first magnetic field component with respect to a first spatial axis and with respect to the reference region. The second magnetoresistive sensor element arrangement is designed to detect a second magnetic field component with respect to a second spatial axis and with respect to the reference region. The third magnetoresistive sensor element arrangement is designed to detect a third magnetic field component with respect to a third spatial axis and with respect to the reference region. Each of the magnetoresistive sensor element arrangements is arranged as a bridge circuit with a plurality of magnetoresistive sensor elements. The spatial axes run along linearly independent position vectors in space.