Asymmetric Magnetic Sensor Shielding Disturbance Fields
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Solution Overview
Problem
Magnetic sensors face reduced detection sensitivity due to disturbance magnetic fields, which existing methods attempt to mitigate by shielding with additional magnetic members, but this often results in lower sensitivity or inefficient field attraction.
Innovation Solution
A magnetic sensor design featuring a first magnetic member with a specific height and a second magnetic member of lower height, strategically positioned to shield disturbance fields while maintaining high detection sensitivity, with optional additional magnetic members and a protection member to enhance shielding and protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a shielding magnetic member is placed on or near the sensor chip to reduce disturbance magnetic field influences, then the shielding effect is improved, but the detection sensitivity is lowered because the detection magnetic field is attracted to the shielding magnetic member
Solution Approach 1:
The patent applies local quality by creating asymmetric magnetic member heights - the first magnetic member has a first height while the second magnetic member has a second height lower than the first height. This localized dimensional differentiation allows the first magnetic member to provide strong shielding against disturbance magnetic fields while the lower second magnetic member minimizes attraction of the detection magnetic field, thus resolving the contradiction between shielding effectiveness and detection sensitivity
Solution Approach 2:
The patent implements asymmetry through the differential heights of the magnetic members. Instead of using symmetric structures, the first magnetic member extends higher than the second magnetic member, creating an asymmetric configuration that optimizes both shielding performance and detection sensitivity by controlling how magnetic fields interact with each member
2Measurement precision
If a magnetic member for collecting magnetic fluxes is placed on the sensor chip to enhance sensitivity to magnetic field in vertical direction, then the detection sensitivity is improved, but the sensor chip becomes exposed to disturbance magnetic fields as noise
Solution Approach 1:
The patent applies local quality by assigning different heights to different magnetic members - the first magnetic member with greater height provides shielding, while the lower second magnetic member collects magnetic fluxes for detection. This localized functional differentiation resolves the contradiction between enhancing detection sensitivity and reducing disturbance magnetic field exposure
Solution Approach 2:
The patent segments the magnetic member structure into two distinct components with different heights and functions. The first magnetic member is dedicated to shielding against disturbance fields, while the second magnetic member focuses on collecting detection magnetic fluxes, thereby resolving the contradiction through functional segmentation
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 effectively reduces the influence of disturbance magnetic fields while maintaining high detection sensitivity, allowing for accurate detection of magnetic fields and enabling applications such as banknote identification devices.
Implementation Method 1
a first magnetic member placed on the element formation surface and having a first height as a height from the element formation surface
Implementation Method 2
a second magnetic member located on an opposite side of the first magnetic detection element to the first magnetic member and having a second height lower than the first height... a disturbance magnetic field is shielded by the second magnetic member
Data Source
AI summary
An object of the present invention is to provide a magnetic sensor that can reduce influences of a disturbance magnetic field while ensuring high detection sensitivity. The magnetic sensor includes a sensor chip 20 having an element formation surface 20S on which magnetic detection elements MR3, MR4 are formed, a first magnetic member 31 placed on the element formation surface 20S and having a first height H1 as a height from the element formation surface 20S, and a second magnetic member 32 located on an opposite side of the magnetic detection elements MR3, MR4 to the first magnetic member 31 and having a second height H2 lower than the first height H1. According to the present invention, because the height H2 of the second magnetic member 32 is lower than that of the first magnetic member 31, a detection magnetic field attracted to the second magnetic member 32 can be reduced while a disturbance magnetic field is shielded by the second magnetic member 32. Accordingly, influences of the disturbance magnetic field can be reduced while high detection sensitivity is ensured.