Magnetic Field Angle Sensor Bridge Structures
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Solution Overview
Problem
Magnetic field sensors, particularly those using GMR and TMR elements, face challenges with linearity and accuracy due to phenomena like spin flop and anisotropy, leading to angle errors in magnetic field angle sensing applications.
Innovation Solution
The implementation of multiple bridge structures with magnetoresistance elements, each measuring magnetic field projections along different axes, and averaging signals to reduce angle errors, combined with adjusting the pinning of reference layers to enhance accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GMR or TMR elements are used for magnetic field sensing, then sensitivity is improved, but linearity deteriorates due to spin flop and anisotropy effects
Solution Approach 1:
The sensing system is divided into multiple independent bridge structures (first bridge structure, second bridge structure, etc.), each measuring magnetic field projections along different axes. By segmenting the measurement into multiple orthogonal components and combining them, the patent achieves both high sensitivity (from GMR/TMR elements) and improved linearity (by averaging out spin flop and anisotropy effects across multiple measurement directions)
2Measurement precision
If multiple bridge structures are used to reduce angle error, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent extends the measurement from a single-axis configuration to multi-dimensional orthogonal measurements by adding bridge structures oriented along different axes (e.g., x-axis, y-axis, z-axis). This dimensional expansion allows angle error reduction through spatial averaging while maintaining a systematic and scalable architecture that manages complexity through geometric symmetry
3Measurement precision
If the pinning of reference layers is adjusted to enhance accuracy, then measurement precision is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent modifies the pinning characteristics of reference layers by changing material composition, layer thickness, or magnetic anisotropy parameters during fabrication. This parameter adjustment optimizes the reference layer stability and measurement accuracy while establishing standardized fabrication parameters that balance performance improvement with manufacturability
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 significantly reduces angle errors in magnetic field angle sensing by averaging signals from multiple bridge structures and modifying the pinning of reference layers, improving the accuracy and linearity of magnetic field measurements.
Implementation Method 1
Some magnetic field sensors include magnetoresistance (MR) elements, such as giant magnetoresistance (GMR) elements and tunneling magnetoresistance (TMR)
Data Source
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AI summary
A magnetic field angle sensor is provided having two or more bridge structures of magnetoresistance elements, each bridge structure configured to measure a projection of a magnetic field along a different axis such that an angle of direction of the magnetic field can be measured with greater accuracy. A first bridge structure is configured to generate a first sinusoidal signal indicative of the magnetic field along a first axis and a first cosinusoidal signal indicative of the magnetic field along a second axis that is orthogonal to the first axis and a second bridge structure is configured to generate a second sinusoidal signal indicative of the magnetic field along a third axis and a second cosinusoidal signal indicative of the magnetic field along a fourth axis that is orthogonal to the third axis, wherein an angle between the first axis and the third axis is a factor of 90°.