Single-Chip Z-X Magnetoresistive Sensor for Angle Measurement
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Solution Overview
Problem
Existing magnetoresistive angle sensors, such as TMRs and GMRs, face challenges in precision and complexity due to their one-way planar magnetic field sensitivity, requiring complicated packaging and mounting procedures, and limited space for a permanent magnet encoding disc, which affects measurement accuracy and increases process complexity.
Innovation Solution
A single-chip Z-X magnetoresistive angle sensor is developed, integrating both X-axis and Z-axis magnetoresistive sensors on a single slice, utilizing a flux concentrator to enhance magnetic field sensitivity and convert Z-axis magnetic fields into X-axis components, allowing for high-sensitivity measurements without a double-slice push-pull structure and providing greater space flexibility for the encoding disc.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a plane X-Y type magnetoresistive sensor chip is employed with rotated slices for X and Y sensitive directions, then magnetic field component measurement is achieved, but measurement precision deteriorates due to mounting position variations and thread connection issues during packaging
Solution Approach 1:
The patent merges the X-axis and Z-axis magnetoresistive sensors onto a single chip substrate, eliminating the need for separate slice mounting and binding operations. This integration removes the sources of mounting position variation and connection errors, directly resolving the precision deterioration issue while maintaining the capability to measure multiple magnetic field components.
Solution Approach 2:
The patent transitions from a planar X-Y sensor configuration to a three-dimensional Z-X configuration by utilizing vertical (Z-axis) magnetoresistive sensing units in addition to the horizontal (X-axis) units. This dimensional change allows measurement of both X and Z magnetic field components on a single chip without requiring slice rotation and binding, thereby maintaining measurement capability while improving precision.
2Ease of operation
If a double-slice push-pull structure is used for X-Y magnetoresistive sensors, then opposite magnetic field sensitive directions are achieved, but process complexity increases due to separate slice mounting and binding operations
Solution Approach 1:
The patent combines the push-pull bridge structure for both X-axis and Z-axis sensing into a single integrated chip design. The push arm and pull arm are formed on the same substrate with consistent fabrication processes, eliminating the need for separate slice mounting and binding. This integration maintains the opposite magnetic field sensitive direction capability while significantly reducing structural complexity.
3Measurement precision
If the sensor chip is placed above the rotation plane region parallel to the permanent magnet encoding disc, then X-Y angle measurement is achieved, but mounting space for the encoding disc is reduced
Solution Approach 1:
The patent changes the measurement plane from the traditional X-Y plane to the Z-X plane by incorporating vertical (Z-axis) magnetoresistive sensing units. This dimensional change allows the sensor chip to be positioned at the edge of the encoding disc rather than above the rotation plane, thereby increasing the available mounting space for the encoding disc while maintaining angle measurement capability through detection of Z and X magnetic field components.
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 solution improves measurement precision, simplifies the sensor manufacturing process, and increases the mounting space for the permanent magnet encoding disc, enhancing the magnetic field homogeneity and flexibility in sensor placement.
Implementation Method 1
employing an enhancing effect of concentrating a magnetic field of a magnetoresistive unit column when a flux concentrator is placed at a position near the magnetoresistive unit column
Implementation Method 2
employing an attenuating effect of shielding the magnetic field of the magnetoresistive unit column when the flux concentrator covers the magnetoresistive unit column
Implementation Method 3
at least one Z-axis magnetoresistive sensor located on the substrate, for detecting a Z-axis magnetic field component perpendicular to the substrate surface
Implementation Method 4
at least one X-axis magnetoresistive sensor located on the substrate, for detecting an X-axis magnetic field component parallel to the substrate surface
Data Source
AI summary
A single-chip off-axis magnetoresistive Z-X angle sensor and measuring instrument. The single-chip off-axis magnetoresistive Z-X angle sensor comprises a substrate located on an X-Y plane, at least one X-axis magnetoresistive sensor and at least one Z-axis magnetoresistive sensor, the X-axis magnetoresistive sensor and the Z-axis magnetoresistive sensor being located on the substrate. The X-axis magnetoresistive sensor and the Z-axis magnetoresistive sensor each comprise magnetoresistive sensing units and a flux concentrator, the magnetoresistive sensing units being electrically connected into a magnetoresistive bridge comprising at least two bridge arms. The Z-axis magnetoresistive sensor is a push-pull bridge structure, a push arm and a pull arm of the push-pull bridge structure being respectively located at positions equidistant from a Y-axis central line of the flux concentrator. The X-axis magnetoresistive sensor is a reference bridge structure, a reference arm and a sensitive arm of the reference bridge structure being respectively located on the Y-axis central line of the flux concentrator and a position more than half of the width of the flux concentrator away from the Y-axis central line. The single-chip off-axis magnetoresistive Z-X angle sensor is placed at an edge of a circular permanent magnet encoding disc and forms an angle measuring instrument. Angle measurement is achieved by measuring X-axis and Z-axis magnetic field components, the structure is compact and sensitivity is high.