Push-pull X-axis Magnetoresistive Sensor with Interlocked Flux Concentrators
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Solution Overview
Problem
Existing push-pull magnetoresistive sensors for X-axis magnetic field detection face challenges in manufacturing complexity and measurement accuracy due to the need for separate chips and wirebonding, which degrades performance.
Innovation Solution
A push-pull X-axis magnetoresistive sensor design utilizing interlocked U-shaped or H-shaped soft ferromagnetic flux concentrators to enhance magnetic field sensitivity and reject Y-axis magnetic fields, with magnetoresistive sensing units placed at interlocked and non-interlocked gaps, and calibration/coils to optimize magnetic field components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If push arm and pull arm are located on separate chips and connected using wirebonds, then magnetic field sensitivity can be improved through push-pull bridge structure, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent merges the push arm and pull arm onto a single substrate, eliminating the need for separate chips and wirebond connections. The interlocked U-shaped or H-shaped soft ferromagnetic flux concentrators are integrated with the magnetoresistive sensing units on the same substrate, simplifying the overall device structure while maintaining the push-pull bridge functionality for enhanced magnetic field sensitivity.
Solution Approach 2:
The patent employs nested flux concentrator structures where U-shaped or H-shaped soft ferromagnetic flux concentrators are interlocked and nested together. The first and second bars of the flux concentrators are positioned to create interlocked gaps that concentrate magnetic fields onto the magnetoresistive sensing units, achieving field enhancement through nested geometric arrangements.
2Measurement precision
If push arm and pull arm are located on separate chips, then push-pull bridge structure can be implemented, but manufacturing process complexity increases due to wirebonding
Solution Approach 1:
The patent combines all sensor components including push arm, pull arm, flux concentrators, and magnetoresistive sensing units onto a single substrate using standard semiconductor fabrication processes. This eliminates the wirebonding step entirely, as all connections are made through integrated circuit techniques during the same manufacturing process, significantly simplifying production.
3Measurement precision
If push arm and pull arm are located on separate chips, then push-pull configuration can be achieved, but measurement accuracy is degraded
Solution Approach 1:
By integrating push and pull arms on the same substrate with precise geometric relationships, the patent ensures accurate alignment and matching of magnetic field paths. The interlocked flux concentrator structure provides well-defined magnetic circuit paths that enhance measurement accuracy through symmetric and balanced magnetic field interactions.
Solution Approach 2:
The patent creates localized magnetic field concentration at specific gaps between the interlocked flux concentrator bars. The magnetoresistive sensing units are positioned at these interlocked gaps where magnetic field lines are concentrated, providing enhanced local sensitivity while maintaining overall measurement accuracy through the symmetric arrangement.
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 achieves enhanced output for X-axis magnetic fields and screening of Y-axis fields, improving measurement accuracy and simplifying manufacturing by integrating components on a single substrate.
Implementation Method 1
interlocked array of soft ferromagnetic flux concentrators... conversion of an external X magnetic field into an enhanced magnetic field
Implementation Method 2
push-pull magnetoresistive bridge sensing unit... push magnetoresistive sensing unit strings... pull magnetoresistive sensing unit strings
Data Source
Figure 1~3
Figure 4(a)~4(b)
Figure 5(a)~5(b)
AI summary
A push-pull X-axis magnetoresistive sensor, comprising: a substrate (6) upon which an interlocked array of soft ferromagnetic flux concentrators (1, 2) and a push-pull magnetoresistive sensor bridge unit are placed. It further may comprise calibration coils (40, 50) and/or initialization coils. At least one of each of the soft ferromagnetic flux concentrators is present such that an interlocking structure may be formed such that there are alternately interlocked and non-interlocked gaps along the X direction. Push/pull magnetoresistive sensing unit strings (7, 8, 81, 71, 72) are respectively located in the interlocked and non-interlocked gaps and are electrically connected to form a push-pull magnetoresistive bridge sensing unit. This magnetoresistive sensing unit is sensitive to magnetic field along the X direction. The calibration coils (40, 50) and initialization coils are respectively compromised of straight calibration conductors (41, 42, 51, 52, 110, 111) and straight initialization conductors (400, 411, 611) that run parallel and perpendicular to the push-pull magnetoresistive sensing unit strings (7, 8, 81, 71, 72). The structure of this push-pull X-axis magnetoresistive sensor is simple to implement. It has the advantages of high magnetic field sensitivity comparing to a referenced bridge X-axis magnetoresistive sensor as well as low power consumption.