Magnetic Sensor Double Spiral Magnetoresistive Elements
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Solution Overview
Problem
Existing magnetic sensors face limitations in achieving isotropy in magnetic field detection, with previous designs not adequately addressing the anisotropy issues in magnetic field detection across various directions.
Innovation Solution
A magnetic sensor design incorporating a bridge circuit with multiple magnetoresistive elements, where first magnetoresistive elements feature double spiral patterns with S-shaped or inverted S-shaped connections, and second magnetoresistive elements have unit patterns defined by folded back bending sections, arranged on virtual circles, polygons, or straight lines, to enhance isotropy by reducing anisotropy and optimizing resistance change rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single magnetoresistive element with simple spiral pattern is used, then device complexity is reduced, but magnetic field detection isotropy deteriorates
Solution Approach 1:
The magnetoresistive element is divided into multiple sections (first section, second section, third section) with different spiral patterns. Each section contributes to detecting magnetic fields in different directional components, and their combined output achieves isotropic detection. The segmentation allows each section to handle specific directional sensitivity while the aggregate provides omnidirectional coverage.
Solution Approach 2:
Multiple magnetoresistive elements with different spiral patterns are electrically connected in parallel to form a composite sensing structure. The first magnetoresistive element has a first spiral pattern, the second has a second spiral pattern, and the third has a third spiral pattern. By merging these elements with different orientation characteristics, the overall sensor achieves isotropic response that none of the individual elements could provide alone.
2Measurement precision
If multiple magnetoresistive elements with different spiral patterns are used, then magnetic field detection isotropy is improved, but device complexity increases
Solution Approach 1:
Different sections of the magnetoresistive element have locally optimized spiral patterns with different characteristics. The first section has a first spiral pattern optimized for certain directional sensitivity, the second section has a second spiral pattern with different characteristics, and the third section has a third spiral pattern. This local differentiation allows each region to contribute specialized detection capability while the overall structure maintains isotropy.
3Measurement precision
If the resistance change rate of first magnetoresistive elements is made greater than second magnetoresistive elements, then sensitivity to magnetic field changes is improved, but balance in bridge circuit deteriorates
Solution Approach 1:
The patent deliberately creates parameter differences between magnetoresistive elements, where the first magnetoresistive elements have a greater resistance change rate than the second magnetoresistive elements. This parameter change is combined with specific pattern configurations (first spiral pattern, second spiral pattern, third spiral pattern) to achieve both high sensitivity and bridge balance. The resistance change rate difference is compensated by the geometric arrangement and electrical connection configuration of the different spiral patterns.
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 magnetic field detection isotropy, reducing variation in output across different magnetic field directions and minimizing anisotropy, thereby enhancing the sensor's ability to detect magnetic fields uniformly across all directions.
Implementation Method 1
a first magnetoresistive element having a first pattern and a second magnetoresistive element having a second pattern, the resistance change rate of the first magnetoresistive element being greater than the resistance change rate of the second magnetoresistive element
Data Source
AI summary
Each of a plurality of first magnetoresistive elements includes a double spiral pattern in plan view. The double spiral pattern includes a first spiral pattern, a second spiral pattern, and an S-shaped or inverted S-shaped pattern that joins the first spiral pattern and the second spiral pattern at a center portion of the double spiral pattern. Orientations of the double spiral patterns of the plurality of first magnetoresistive elements are different from each other in a circumferential direction, and orientations of the S-shaped or inverted S-shaped patterns differ from each other in the circumferential direction.