Bias Field Generation for Magneto Sensor Using Inclined Cavity
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Solution Overview
Problem
Magnetoresistive sensors face limitations in sensitivity due to saturation and require a bias magnetic field, which can be challenging to manage with traditional large bias magnets, especially in applications like rotational speed detection, where accurate positioning and sensitivity are critical.
Innovation Solution
A bias field generator with a body of permanent or magnetizable material having a cavity with inclined surface sections, allowing independent control of magnetic field components and reducing lateral field components, enabling smaller device dimensions and increased sensitivity without degrading performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional large bias magnets are used, then the bias magnetic field can be provided, but the device dimensions become large and positioning requirements become strict
Solution Approach 1:
The bias field generator is segmented into multiple permanent magnets arranged in a specific configuration (e.g., alternating polarity arrangement) rather than using a single large magnet. This segmentation allows the device to maintain the required bias field strength while reducing overall device dimensions and relaxing positioning tolerances.
Solution Approach 2:
The patent transitions from using a single large bias magnet to a multi-magnet arrangement in a planar configuration. By distributing the magnetic field generation across multiple smaller magnets arranged in two dimensions, the system achieves the same bias field effect with reduced device footprint and improved positioning tolerance.
2Reliability
If traditional large bias magnets are used, then the bias magnetic field can be provided, but lateral field components increase and sensitivity degrades
Solution Approach 1:
The patent employs an asymmetric arrangement of permanent magnets with alternating polarities, where the magnetic moments are oriented in a specific asymmetric pattern. This asymmetric configuration generates a bias field that minimizes lateral field components while maintaining the required vertical bias field strength, thereby improving sensor sensitivity.
Solution Approach 2:
The patent optimizes parameters such as magnet size, spacing, and magnetic moment orientation to minimize lateral field components. By carefully adjusting these parameters in the multi-magnet configuration, the system achieves reduced lateral field interference while maintaining effective bias field generation.
3Reliability
If magnetoresistive sensors operate outside the anisotropic range, then saturation limits occur, but maintaining operation within the working range requires precise bias field control
Solution Approach 1:
The multi-magnet bias field generator serves multiple functions: it provides the primary bias field, minimizes lateral field components, and maintains stable operation across the sensor's working range. This universal design eliminates the need for additional complex control mechanisms to maintain operation within the anisotropic range.
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 approach enhances sensitivity by eliminating or reducing lateral field components, allowing for smaller device sizes and relaxed positioning requirements, while avoiding the need for large bias magnets, thus improving the operational range and cost-effectiveness of magnetoresistive sensors.
Implementation Method 1
Magnetoresistive effects used in magnetoresistive sensors include but are not limited to GMR (Giant Magnetoresistance), AMR (Anisotropic Magnetoresistance), TMR (Magneto Tunnel Effect), CMR (Colossal Magnetoresistance)
Implementation Method 2
a bias field generator to generate a bias magnetic field having a field component in a first direction, wherein the bias field generator comprises a body of permanent magnetic material or magnetizable material with a cavity
Data Source
AI summary
Embodiments related to the generation of magnetic bias fields for magnetic sensing are described and depicted. In one embodiment, a sensor includes at least one magnetosensitive element, and a magnetic body with an opening, the magnetic body comprising magnetic material, the magnetic body having inclined surface sections shaped by the opening, wherein the sensor is arranged within the opening such that the magnetosensitive element is in lateral directions bounded by the inclined surface sections.