Magnetic Sensor Isotropy via Segmented Spiral Magnetoresistive Elements
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Solution Overview
Problem
Existing magnetic sensors with non-rectangular magnetoresistive elements often have excess space, limiting their size reduction and isotropy in magnetic field detection.
Innovation Solution
A magnetic sensor with a rectangular substrate and magnetoresistive elements featuring radiating slits and bent patterns, forming a bridge circuit with alternating directions, and including second magnetoresistive elements with low resistance change, arranged in a circular or polygonal pattern to enhance isotropy and reduce size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the outer shape of the magnetoresistive element is made non-rectangular to improve isotropy, then magnetic field detection isotropy is improved, but excess space is created around the element, increasing the overall sensor size
Solution Approach 1:
The magnetoresistive element is divided into multiple segments by introducing slits that radiate from the center toward the outer edge. These slits create multiple independent magnetic sensing regions that collectively provide omnidirectional magnetic field detection while maintaining a compact rectangular overall shape that fits efficiently within the substrate.
Solution Approach 2:
The patent transitions from a simple planar pattern to a three-dimensional spiral structure that winds around the center. This spiral configuration allows the magnetic sensing path to extend in multiple directions (radially and tangentially) within a compact footprint, achieving isotropy without requiring excessive planar space.
2Area of stationary object
If the magnetoresistive element is made rectangular to minimize sensor size, then device compactness is improved, but magnetic field detection isotropy deteriorates
Solution Approach 1:
The rectangular magnetoresistive element is segmented by radiating slits that divide the element into multiple magnetic sensing regions. This segmentation allows the element to maintain its compact rectangular outer shape while creating internal magnetic paths that detect fields from all directions, thus achieving both small size and isotropy.
Solution Approach 2:
The patent introduces asymmetric slit patterns and spiral windings within the rectangular boundary. These asymmetric internal structures create magnetic sensing paths that are not aligned with the rectangular boundaries, enabling omnidirectional detection while the overall element maintains a symmetric rectangular shape for space efficiency.
3Measurement precision
If spiral patterns with curved portions are used to improve isotropy, then magnetic field detection isotropy is improved, but manufacturing complexity increases
Solution Approach 1:
The spiral pattern is segmented into discrete turns or segments separated by radial slits. This segmentation allows the pattern to be manufactured using standard photolithography and etching processes by defining each segment as a separate feature, reducing the difficulty of creating continuous curved patterns while maintaining the isotropic sensing capability.
Solution Approach 2:
The patent uses controlled curvature in the spiral pattern to achieve isotropy. The curved spiral path allows magnetic flux to be detected from multiple angles, and the curvature is designed to be consistent with standard fabrication capabilities, balancing isotropy 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
The design significantly improves isotropy in magnetic field detection while minimizing sensor size by efficiently arranging magnetoresistive elements, reducing excess space and anisotropy effects.
Implementation Method 1
a magnetoresistive element having a pattern that has a rectangular or substantially rectangular outer shape in plan view
Data Source
AI summary
A magnetic sensor includes a rectangular or substantially rectangular substrate and at least one first magnetoresistive element on the substrate. The first magnetoresistive element has a pattern that, in plan view, has a rectangular or substantially rectangular outer shape and includes first slits that extend in a radiating manner from a center of the pattern and approach an outer edge of the pattern and second slits between adjacent first slits and extend from the outer edge of the pattern toward the center of the pattern. The pattern is connected to circle around the center of the pattern while alternately changing direction between a first direction toward the outer edge of the pattern and a second direction toward the center of the pattern.