Magnetic Sensor Protruding External Member Reduces Flux Leakage
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Solution Overview
Problem
Magnetic sensors with large air gaps between external magnetic members suffer from magnetic flux leakage, resulting in insufficient detection sensitivity.
Innovation Solution
A magnetic sensor design featuring a sensor substrate with first and second external magnetic members that protrude from the element forming surface, reducing magnetic flux leakage and enhancing detection sensitivity by concentrating magnetic flux on the sensing elements. The second external magnetic member has a tapered shape and overhanging parts to further reduce magnetic resistance and flux bypass.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If external magnetic members are provided with large air gaps, then the structure is simpler and easier to manufacture, but magnetic flux leakage increases reducing detection sensitivity
Solution Approach 1:
The second external magnetic member extends in the thickness direction (z-direction) beyond the element forming surface, creating a three-dimensional structure. This dimensional extension allows the magnetic member to effectively cover and reduce air gaps on both side surfaces of the sensor substrate, concentrating magnetic flux without increasing planar complexity
Solution Approach 2:
The first and second parts of the second external magnetic member are positioned at different locations (side surfaces) of the sensor substrate, with each part locally reducing air gaps at its respective position. This localized approach concentrates magnetic flux where needed while maintaining overall structural simplicity
2Measurement precision
If external magnetic members are positioned close together, then magnetic flux is concentrated on sensing elements improving sensitivity, but manufacturing precision requirements increase
Solution Approach 1:
By extending the second external magnetic member in the thickness direction, the design achieves effective proximity to both side surfaces without requiring high precision in the planar positioning of multiple separate members. The single extended structure reduces cumulative positioning errors
3Measurement precision
If the second external magnetic member has protruding parts, then magnetic flux leakage is reduced enhancing detection sensitivity, but device complexity increases
Solution Approach 1:
The first and second parts of the second external magnetic member are formed as a single integrated piece rather than separate components. This merging reduces the number of parts and assembly steps while achieving the dual function of covering both side surfaces and reducing air gaps
Solution Approach 2:
The second external magnetic member serves multiple functions: it covers both side surfaces of the sensor substrate, reduces air gaps at both positions, and concentrates magnetic flux on the sensing elements. This multi-functionality reduces the need for additional separate components
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 enhances magnetic field detection sensitivity by minimizing magnetic flux leakage and resistance, outperforming conventional sensors in sensitivity.
Implementation Method 1
the first and second parts of the second external magnetic member protrude from the element forming surface, so that leakage of magnetic flux between the first and second external magnetic members is reduced. This concentrates magnetic flux more on the magnetic sensing element
Implementation Method 2
a plurality of magnetic sensing elements including first and second magnetic sensing elements are formed
Data Source
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AI summary
An object of the present invention is to reduce leakage magnetic flux in a magnetic sensor provided with a sensor substrate and an external magnetic member. A magnetic sensor includes: a sensor substrate 20 having an element forming surface 20a on which magnetic sensing elements R1 and R2 are formed, first and second side surfaces 21 and 22, and a back surface 23; a first external magnetic member 30 provided between the first and second magnetic sensing elements R1 and R2; and a second external magnetic member 40 having first and second parts 41 and 42 covering the first side surface 21 and second side surface 22, respectively. The first and second parts 41 and 42 of the second external magnetic member 40 protrude from the element forming surface 20a. According to the present invention, since the first and second parts 41 and 42 of the second external magnetic member 40 protrude from the element forming surface 20a, leakage of magnetic flux between the first and second external magnetic members 30 and 40 is reduced.