MEMS Triaxial Magnetic Sensor with Decoupled Elastic Structure
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Solution Overview
Problem
Current MEMS triaxial magnetic sensors have high area occupation, electrical power consumption, and suboptimal electrical performance, including sensitivity, offset, and disturbance rejection, due to their multi-sensing structure design.
Innovation Solution
A MEMS triaxial magnetic sensor with a single monolithic sensing structure and decoupling elastic elements, allowing distinct and decoupled sensing movements for three orthogonal magnetic-field components, utilizing a spiral conductive path and capacitive detection to reduce area and power consumption while maintaining sensitivity and noise performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple sensing structures are used for triaxial magnetic field detection, then sensitivity and detection accuracy are improved, but area occupation and device complexity increase
Solution Approach 1:
The patent combines three separate sensing structures into a single integrated sensing structure that can detect magnetic fields along three orthogonal axes simultaneously. The mobile structure contains conductive paths arranged in three orthogonal directions, allowing one structure to perform the function of three separate structures, thereby reducing area occupation while maintaining triaxial detection capability
Solution Approach 2:
The single sensing structure is designed with multi-functional conductive paths that can sense magnetic field components along three different axes. The mobile structure serves multiple detection purposes simultaneously, making it a universal sensing element that replaces multiple specialized structures
2Measurement precision
If multiple sensing structures are used for triaxial magnetic field detection, then detection accuracy is improved, but power consumption increases
Solution Approach 1:
By merging three sensing structures into one, the patent reduces the total number of conductive paths and associated readout circuits required. This consolidation decreases the overall power consumption while maintaining the capability to detect all three magnetic field components with the same accuracy
3Measurement precision
If multiple sensing structures are used for triaxial magnetic field detection, then detection accuracy is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent merges multiple sensing structures into a single monolithic sensing structure that can be fabricated using standard MEMS processes. This integration simplifies the manufacturing workflow, reduces the number of fabrication steps, and lowers production costs compared to assembling or fabricating three separate structures
Solution Approach 2:
Within the single mobile structure, the conductive paths are segmented into three orthogonal components, each responsible for detecting magnetic field along a specific axis. This segmentation allows independent optimization of each sensing direction while maintaining a unified structure that simplifies manufacturing
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 solution achieves a significant reduction in area occupation and electrical consumption while maintaining or improving sensitivity and noise performance, enabling efficient detection of magnetic fields along three axes with minimized offset and spurious modes.
Implementation Method 1
a first sensing movement in response to Lorentz forces originating from a first magnetic-field component; a second sensing movement in response to Lorentz forces originating from a second magnetic-field component; and a third sensing movement in response to Lorentz forces originating from a third magnetic-field component
Implementation Method 2
elastically coupled to the first anchorages by the first elastic elements; elastically coupled to the outer frame by the second elastic elements; The mobile structure is configured to perform, due to the first and second elastic elements and of the elastic arrangement: a first sensing movement; a second sensing movement; and a third sensing movement
Implementation Method 3
the extent of this movement, which may for example be detected with the capacitive technique, is indicative of the magnetic field value
Data Source
AI summary
A MEMS triaxial magnetic sensor device includes a sensing structure having: a substrate; an outer frame, which internally defines a window and is elastically coupled to first anchorages fixed with respect to the substrate by first elastic elements; a mobile structure arranged in the window, suspended above the substrate, which is elastically coupled to the outer frame by second elastic elements and carries a conductive path for flow of an electric current; and an elastic arrangement operatively coupled to the mobile structure. The mobile structure performs, due to the first and second elastic elements and the arrangement of elastic elements, first, second, and third sensing movements in response to Lorentz forces from first, second, and third magnetic-field components, respectively. The first, second, and third sensing movements are distinct and decoupled from one another.