Magnetic Field Sensor With Segmented Deflection Bodies

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Solution Overview

Problem

Existing magnetic field sensors face challenges in achieving homogeneous and strong magnetic field penetration across the active surface of magneto-sensitive elements, particularly when the active surface is aligned parallel to the magnetic field, leading to reduced signal strength and interference from extraneous fields, and existing deflection arrangements are limited in adaptability and prone to edge effects.

Innovation Solution

The use of multiple ferromagnetic deflection bodies, such as four or five flat platelet-shaped deflection bodies, arranged to overlap and allow magnetic field lines to penetrate the active surface vertically with maximum field strength, eliminating edge effects and enabling better adaptation to different magnetic field configurations and interference suppression.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a single plate-shaped deflection body is used to redirect magnetic field lines perpendicular to the active surface, then the magnetic field can be made to penetrate the active surface, but the field strength varies greatly over the active surface and edge effects dominate

Engineering Contradiction:
Improvemagnetic field penetration qualityVSAvoidfield homogeneity
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The single deflection body is divided into multiple deflection bodies (at least two, preferably three or four) arranged around the magneto-sensitive element. Each deflection body handles a portion of the magnetic field redirection, distributing the field lines more evenly across the active surface and reducing edge effects that dominate with a single plate.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the active surface are provided with locally optimized magnetic field conditions through the strategic placement of multiple deflection bodies. The deflection bodies are positioned and dimensioned to create overlapping magnetic field paths that ensure homogeneous field penetration across different areas of the active surface.

Inventive Principle:
Principle #3Local quality

2Device complexity

If the active surface is aligned parallel to the magnetic field direction, then the sensor structure is simplified, but the signal strength decreases and disappears when field lines run parallel to the active surface

Engineering Contradiction:
Improvesensor structureVSAvoidsignal strength
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

Multiple deflection bodies act as intermediary ferromagnetic structures that redirect the magnetic field lines from a parallel orientation to a perpendicular orientation relative to the active surface. These deflection bodies serve as mediators that transform the magnetic field direction without requiring physical repositioning of the magneto-sensitive element, thus maintaining structural simplicity while improving signal strength.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Volume of moving object

If the diameter of the deflection body is reduced to accommodate closely spaced Hall elements, then positioning and balancing becomes more difficult, but the compact design is maintained

Engineering Contradiction:
Improvesensor sizeVSAvoidpositioning and balancing
Core Design Contradiction:
Volume of moving objectVSEase of manufacture

Solution Approach 1:

The deflection function is segmented across multiple smaller deflection bodies rather than requiring one large deflection body. This segmentation allows the use of smaller, more manageable components that are easier to position and balance, while collectively providing the same or enhanced field reinforcement effect.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple deflection bodies are merged in their magnetic field effect to provide cumulative field reinforcement. The overlapping magnetic field paths created by multiple deflection bodies result in enhanced field strength at the active surface, compensating for the smaller individual size of each deflection body.

Inventive Principle:
Principle #5Merging (Combining)

4Device complexity

If a single deflection body is used, then the structure is simple, but there are no design options for adaptation to different magnetic field configurations and elimination of interfering extraneous fields

Engineering Contradiction:
Improvedeflection structureVSAvoidmagnetic field configuration adaptation
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The deflection structure becomes dynamically adaptable through the use of multiple deflection bodies that can be independently positioned, dimensioned, and oriented. This configuration allows the magnetic field deflection characteristics to be optimized for different magnetic field configurations and interference patterns by adjusting the arrangement of the multiple deflection bodies.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The multiple deflection bodies serve multiple functions: they redirect the primary magnetic field perpendicular to the active surface, reinforce the field strength through overlapping paths, and can be configured to eliminate interfering extraneous fields. This multi-functionality provides adaptability to different magnetic field configurations without requiring fundamentally different structural approaches.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

This configuration enhances the homogeneity and strength of the magnetic field, suppresses interference fields, and allows for more favorable adaptation to various magnetic field configurations, achieving improved signal quality and accuracy in magnetic field detection.

Implementation Method 1

a magnetic field deflection device which consists of a single plate-shaped deflection body made of ferromagnetic material which is arranged in such a way with respect to the Hall element

Methodology Applied
Scientific EffectMagnetic field deflection: Magnetic Field

Implementation Method 2

deflection bodies made of ferromagnetic material

Methodology Applied
Scientific EffectFerromagnetism: Ferromagnetism

Implementation Method 3

field lines that would run parallel to the active surface of the magneto-sensitive element without the presence of the deflection bodies can pass from one deflection body to the other unaffected by edge effects

Methodology Applied
Scientific EffectMagnetic flux concentration: Magnetic Field

Implementation Method 4

Hall element must be aligned in such a way that it is traversed by the magnetic field lines with at least one component that is perpendicular to it

Methodology Applied
Scientific EffectHall effect: Hall Effect

Data Source

PatentEP2572166B1Magnetic field sensor for a position detector
Publication Date: 2017.08.02 AVAGO TECHNOLOGIES GENERAL IP (SINGAPORE) PTE LTD
  • EP2572166B1 patent drawingFigure 1~3
  • EP2572166B1 patent drawingFigure 4~5
  • EP2572166B1 patent drawingFigure 6~8

AI summary

A magnetic field sensor for a position transmitter, comprising at least one magnetosensitive element (3) having an active surface, on which magnetosensitive element an electric signal is tappable that changes as a function of the field strength of that component of a moving magnetic field which pervades the active surface perpendicularly, and comprising a ferromagnetic magnetic field deflection device (10, 11), which is arranged to be positionally fixed with respect to the at least one magnetosensitive element (3) such that said magnetic field deflection device deflects magnetic field lines (F), which would otherwise run parallel to the active surface, such that they pervade the active surface with a component that is perpendicular thereto, is characterized in that the magnetic field deflection device comprises at least two ferromagnetic deflection bodies (10, 11) which are arranged in two parallel planes with their planar base areas, which face one another, such that they form at least one overlap region, in which at least one magnetosensitive element (3) is situated.