Dual-axis AMR Sensor with Angled Strips for Multi-Field Sensing
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Solution Overview
Problem
Multi-axis bridge-type AMR sensors constrained to a single technological anisotropy axis face challenges in aligning sensitivity maximally to multiple orthogonal vector components of ambient magnetic fields, leading to performance degradation and limited design flexibility.
Innovation Solution
A dual-axis AMR sensor design with x-axis and y-axis sensor units, each comprising magnetoresistive strips aligned at specific angles relative to the technological anisotropy axis, allowing for primary sensitivity to respective ambient field components while minimizing sensitivity to orthogonal components, thereby enhancing performance and design flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If anisotropic magnetoresistive materials with multiple technological anisotropy axes are used to implement multi-axis AMR sensors, then sensitivity to multiple orthogonal vector components can be maximized, but manufacturing complexity and cost increase significantly
Solution Approach 1:
The sensor is divided into multiple sensor units, where each unit is configured to sense a specific vector component. By segmenting the sensing function across multiple units with different orientations, the system achieves multi-axis sensitivity without requiring materials with multiple anisotropy axes, thereby simplifying manufacturing while maintaining measurement precision.
Solution Approach 2:
A single layer of anisotropic magnetoresistive material with one technological anisotropy axis is made multi-functional by configuring multiple sensor units with different strip orientations. This universal material layer serves multiple sensing purposes (x-axis, y-axis, and potentially z-axis components) through geometric arrangement rather than material complexity.
2Measurement precision
If the shape anisotropy axis is aligned perpendicular to the technological anisotropy axis to maximize sensitivity, then the sensitivity axis becomes perpendicular to total anisotropy axis, but magnetization uniformity degrades and sensitivity is reduced
Solution Approach 1:
Instead of using a perpendicular alignment between shape and technological anisotropy axes, the invention changes the angular parameter to a non-perpendicular orientation (e.g., 45 degrees). This parameter modification simultaneously achieves acceptable magnetization uniformity and maintains sufficient sensitivity to ambient magnetic fields, resolving the contradiction between these two requirements.
3Ease of manufacture
If anisotropic magnetoresistive materials with a single technological anisotropy axis are used, then manufacturing is simplified and cost is reduced, but alignment flexibility for multi-axis sensing is limited
Solution Approach 1:
The invention introduces asymmetric orientations of magnetoresistive strips relative to the technological anisotropy axis. By using different angular orientations (e.g., 0 degrees for y-axis sensing, 45 degrees for x-axis sensing) in different sensor units, the system achieves multi-axis alignment flexibility while maintaining manufacturing simplicity through the use of a single material layer with one anisotropy axis.
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 dual-axis AMR sensor effectively senses and outputs signals for both x-axis and y-axis ambient magnetic field components with improved sensitivity and reduced noise, achieving better performance and cost-effectiveness by using a single layer of anisotropic magnetoresistive material with a single technological anisotropy axis.
Implementation Method 1
AMR sensors rely on the anisotropic sensitivity of the resistivity of certain magnetic materials to implement electric or electronic circuits, which can then provide outputs representing properties of sensed ambient magnetic fields.
Implementation Method 2
If an ambient field is present, it rotates the angle of magnetization existing in the resistor material, with the greatest rotation, and the greatest change in resistivity of the magnetoresistor, being when the ambient field acts perpendicular to the total anisotropy axis
Data Source
Figure 1~4
Figure 2
Figure 3~7E
AI summary
An integrated dual-axis anisotropic magnetoresistive sensor can include a first sensor unit and a second sensor unit. The first sensor unit can have a resistor bridge including a plurality of magnetoresistors, each having at least one elongated strip of anisotropic magnetoresistive material having a longitudinal axis substantially parallel to a technological anisotropy axis of the magnetoresistive material. The second sensor unit can have a resistor bridge including a plurality of magnetoresistors having a plurality of elongated strips of anisotropic magnetoresistive material, wherein the plurality of strips includes a first subset of strips having longitudinal axes aligned at a first angle to the technological anisotropy axis and a second subset of strips having longitudinal axes aligned at a second angle to the technological anisotropy axis.