Single-Chip Three-Axis Magnetic Sensor With Shielding
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Solution Overview
Problem
Traditional magnetic field sensing devices can only measure magnetic fields parallel to a substrate, lacking the ability to sense fields perpendicular to the substrate, and integrating three-axis sensing on a single substrate while preventing cross-axis interference remains a technological challenge.
Innovation Solution
A single-chip three-axis magnetic field sensing device is designed with a substrate hosting three sensing modules: one for each axis, utilizing magnetoresistive elements and a coil to set magnetization directions and sense magnetic fields parallel and perpendicular to the surface, ensuring independent and precise measurement of X-axis, Y-axis, and Z-axis fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional magnetoresistive elements are used to sense magnetic fields parallel to the substrate, then the sensing capability for X-axis and Y-axis magnetic fields is achieved, but the ability to sense Z-axis magnetic fields perpendicular to the substrate is lost
Solution Approach 1:
The patent introduces a third sensing module with magnetoresistive elements oriented perpendicular to the substrate surface, adding a new dimension (Z-axis) to the traditional two-dimensional (X-Y axis) sensing capability. This dimensional extension enables the device to detect magnetic field components in all three spatial directions simultaneously.
Solution Approach 2:
The sensing device is divided into three independent sensing modules, each responsible for detecting magnetic field components along a specific axis (X-axis, Y-axis, and Z-axis). This segmentation allows each module to be optimized for its specific sensing direction while working together as an integrated three-axis sensing system.
2Device complexity
If multiple magnetic field sensing devices for different axes are integrated into the same substrate, then the integration and simplicity are improved, but cross-axis interference between X-axis, Y-axis and Z-axis sensing occurs
Solution Approach 1:
Each sensing module is designed with specific local characteristics: the first and second sensing modules use magnetoresistive elements with magnetization directions parallel to the substrate for X and Y axis sensing, while the third sensing module uses magnetoresistive elements with magnetization directions perpendicular to the substrate for Z axis sensing. This local differentiation in element orientation enables axis-specific sensing while minimizing cross-interference.
Solution Approach 2:
Magnetic field shielding structures are introduced as intermediary elements between the different sensing modules. These shielding structures act as mediators that block or redirect magnetic field lines, preventing magnetic fields from one axis from interfering with the sensing elements of other axes, thereby isolating each sensing channel.
3Productivity
If three sensing modules for X-axis, Y-axis and Z-axis are integrated on a single chip, then the simplicity and integration are enhanced, but the manufacturing precision and alignment accuracy become more difficult to control
Solution Approach 1:
The patent employs preliminary actions in the manufacturing process by pre-defining the magnetization directions of the magnetoresistive elements during fabrication. The magnetization directions are established beforehand through controlled magnetic field application and thermal treatment, ensuring that the elements are pre-aligned to their intended sensing axes before final assembly, which simplifies subsequent alignment procedures.
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
Enables simultaneous and precise sensing of X-axis, Y-axis, and Z-axis magnetic fields on a single substrate, enhancing integration and precision while minimizing cross-axis interference, thus improving the simplicity and performance of magnetic field sensing.
Implementation Method 1
a first sensing module comprising at least one first magnetoresistive element and configured to sense a first magnetic field component substantially parallel to the surface
Implementation Method 2
the at least one coil is configured to set a magnetization direction of the magnetoresistive element right above or right below it
Data Source
AI summary
A single-chip three-axis magnetic field sensing device is provided. This single-chip three-axis magnetic field sensing device comprises a substrate, a first sensing module, a second sensing module, a third sensing module and at least one coil. The substrate includes a surface. The first sensing module comprises at least one first magnetoresistive element and is configured to sense a first magnetic field component substantially parallel to the surface. The second sensing module comprises at least one second magnetoresistive element and is configured to sense a second magnetic field component substantially parallel to the surface. The third sensing module comprises at least one third magnetoresistive element and is configured to sense a third magnetic field component substantially perpendicular to the surface. Wherein one of the first magnetoresistive element and the second magnetoresistive element and the third magnetoresistive element is disposed right above or right below the at least one coil.