Segmented Magnetic Shield for Multiturn Sensor Yield
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Solution Overview
Problem
Multiturn sensors face challenges in achieving a high magnetic field window while maintaining a moderately wide magnetic strip width, as narrow strips are difficult to form and result in manufacturing yield degradation, and existing magnetic shields can saturate at certain magnetic field strengths, affecting shielding effectiveness.
Innovation Solution
A magnetic sensor design incorporating a magnetic shield with ferromagnetic portions spaced apart by non-ferromagnetic material, allowing partial shielding of the magnetic field to enhance the magnetic field window without the need for narrow strip widths, and featuring a passivation layer for protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a narrow magnetic strip width is used to achieve a high magnetic field window, then the magnetic field sensing capability is improved, but the manufacturing yield deteriorates due to difficulty in forming narrow strips
Solution Approach 1:
The magnetic shield is segmented into multiple ferromagnetic portions spaced apart by non-ferromagnetic material. This segmentation allows the shield to effectively manage magnetic flux without requiring narrow strip widths, thereby maintaining manufacturing yield while achieving the desired magnetic field window.
Solution Approach 2:
A magnetic shield comprising ferromagnetic portions spaced apart by non-ferromagnetic material is introduced as an intermediary element between the magnetic field source and the sensing element. This shield mediates the magnetic field interaction, enabling a high magnetic field window without requiring narrow strip widths.
2Measurement precision
If a magnetic shield is used to enhance the magnetic field window, then the magnetic field sensing capability is improved, but the shielding effectiveness deteriorates when the shield saturates at certain magnetic field strengths
Solution Approach 1:
The magnetic shield is divided into multiple ferromagnetic portions spaced apart by non-ferromagnetic material. This segmentation prevents magnetic flux concentration that leads to saturation, maintaining shielding effectiveness across a broader range of magnetic field strengths while enhancing the magnetic field window.
Solution Approach 2:
Different regions of the magnetic shield have different properties: ferromagnetic portions provide shielding where needed, while non-ferromagnetic spacing regions prevent flux concentration and saturation. This local differentiation maintains reliability across varying magnetic field conditions.
3Measurement precision
If ferromagnetic portions are spaced laterally apart by non-ferromagnetic material in the magnetic shield, then the magnetic field window is enhanced, but the device complexity increases
Solution Approach 1:
The non-ferromagnetic material is extracted as a distinct spacing element between ferromagnetic portions. This extraction creates a simple, repeatable structural unit that enhances the magnetic field window while keeping the overall device complexity manageable through modular construction.
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 provides a multiturn sensor with a high magnetic field window and improved manufacturing yield by effectively shielding a portion of the magnetic field, allowing a wider magnetic strip width while maintaining accurate turn counting and reducing manufacturing challenges.
Implementation Method 1
The magnetic shield plate is configured to shield a portion of a magnetic field allowing an un-shielded portion of the magnetic field to pass through
Implementation Method 2
The magnetic shield plate can include ferromagnetic portions that are spaced laterally apart from each other by a non-ferromagnetic material
Implementation Method 3
An example of electromagnetic multiturn sensor includes a giant magnetoresistance (GMR) sensor and a tunneling magnetoresistance (TMR) sensor
Data Source
AI summary
A magnetic sensor is disclosed. The magnetic sensor can include a sensing element and a magnetic shield. The sensing element and the magnetic shield can be vertically stacked with one another. The magnetic shield can be a magnetic shield plate that includes ferromagnetic portions spaced laterally by a non-ferromagnetic material. The sensing element can have a first side and a second side opposite the first side. The magnetic shield that can be vertically stacked over the first side of the sensing element. The magnetic shield can be spaced apart from the sensing element by an isolation layer. A passivation layer can cover at least a portion of the sensing element or the magnetic shield. The sensing element can be configured to sense a magnetic field property of a magnetic field source that is positioned on the second side of the sensing element.