Multi-Track Position Sensor Decoupling Accuracy from Substrate Size
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Solution Overview
Problem
Existing magnetic sensor systems face challenges in achieving high accuracy and cost-effectiveness while being robust against ageing effects and external disturbance fields.
Innovation Solution
A position sensor system with a magnetic source having multiple tracks with different periodicities and a sensor device that measures orthogonal magnetic field components at multiple locations, allowing for independent optimization of the sensor device and magnetic source, and reducing the size and cost of the semiconductor substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the sensor device dimensions are reduced to lower cost and decrease substrate footprint, then manufacturing cost and chip area are reduced, but measurement accuracy and signal-to-noise ratio deteriorate
Solution Approach 1:
The magnetic source is segmented into multiple independent tracks, each with different periodicities. This allows the sensor device to use a fixed baseline distance while the multi-track configuration provides the necessary measurement resolution and accuracy without requiring a large sensor footprint.
Solution Approach 2:
The patent transitions from a single-track configuration to a multi-track configuration with different periodicities. This dimensional change in the magnetic field structure allows the sensor to achieve high measurement accuracy with a compact baseline distance, effectively decoupling accuracy requirements from physical sensor dimensions.
2Measurement precision
If multiple tracks with different periodicities are used to improve measurement accuracy, then measurement precision is improved, but device complexity and processing requirements increase
Solution Approach 1:
Each track is designed with a specific periodicity optimized for particular measurement ranges. The system uses local quality variations in the magnetic field structure (different periodicities at different tracks) to achieve both wide measurement range and high accuracy without requiring complex sensor hardware.
Solution Approach 2:
The multi-track magnetic source serves multiple functions simultaneously: it provides measurement across different ranges, achieves high accuracy, and enables determination of transverse position. This universal design reduces the need for separate systems for different measurement requirements.
3Measurement precision
If the baseline distance between sensor locations is increased to improve transverse position determination, then transverse position accuracy is improved, but the sensor device footprint and cost increase
Solution Approach 1:
The magnetic source is divided into multiple tracks spaced at different distances from the sensor. This segmentation allows the system to determine transverse position accurately using the relative signal strengths from different tracks, eliminating the need for a large baseline distance between sensor elements.
Solution Approach 2:
The multi-track magnetic source structure acts as an intermediary that enables transverse position determination. By measuring the magnetic field from multiple tracks at a fixed baseline distance, the system can calculate transverse position without requiring the sensor elements to be far apart.
4Reliability
If robustness against external disturbance fields is improved through multiple measurements, then reliability is improved, but processing power and computational requirements increase
Solution Approach 1:
The system extracts position information from the ratio of magnetic field measurements rather than requiring complex processing of absolute field values. This extraction of relative information reduces computational requirements while maintaining robustness against external disturbance fields that would affect all measurements similarly.
Solution Approach 2:
The patent changes the parameter being measured from absolute magnetic field strength to the ratio of field strengths at different tracks. This parameter transformation makes the measurement inherently more robust to external disturbances while reducing the processing power needed, as ratio calculations are computationally simpler than full field analysis.
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 achieves improved accuracy and reduced costs by allowing the sensor device dimensions to be independent of the magnetic source track distances, and is more robust against ageing and external disturbances.
Implementation Method 1
a position sensor system with a magnetic source having multiple tracks with different periodicities and a sensor device that measures orthogonal magnetic field components
Data Source
AI summary
A position sensor system is arranged for determining a position of a sensor device movable along a predefined path relative to a magnetic source. The system includes the magnetic source and the sensor device. The magnetic source has a first plurality of magnetic pole pairs arranged along a first track and a second plurality of magnetic pole pairs arranged along a second track, centrelines of the tracks are spaced apart by a predefined track distance. The sensor device is configured for measuring at least two orthogonal magnetic field components at a first sensor location, and at least two second orthogonal magnetic field components at a second sensor location. The first and second sensor location are spaced apart by a predefined sensor distance smaller than the predefined track distance, in a direction transverse to the tracks.