Hall Sensor Magnetic Field Alignment for Ferromagnetic Position Detection

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Solution Overview

Problem

Existing integrated magnetic field sensors with Hall sensors and permanent magnets have low sensitivity due to geometric alignment, resulting in minimal or no Hall voltage without external ferromagnetic influence, limiting their ability to detect changes in magnetic flux density effectively.

Innovation Solution

The integration of a semiconductor body and permanent magnet on a common metal carrier, with magnetic field lines aligned parallel to the main extension plane of the Hall sensor, increases sensitivity by generating a Hall voltage only when a ferromagnetic component alters the flux density, allowing for precise position determination of the ferromagnetic component through calibration and Hall voltage measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the Hall sensor is geometrically aligned to the permanent magnet, then the device complexity is reduced and manufacturing is simplified, but the sensitivity is reduced and Hall voltage is minimized without external ferromagnetic influence

Engineering Contradiction:
Improvegeometric alignment simplicityVSAvoidsensitivity
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

Instead of aligning the Hall sensor to detect magnetic field lines directly from the permanent magnet (conventional approach), the patent inverts the approach by aligning the Hall sensor parallel to the magnetic field lines, deliberately creating a configuration where no Hall voltage is generated without external ferromagnetic influence. This inverted geometry makes the sensor specifically sensitive to changes caused by external ferromagnetic components.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent changes the geometric parameter of the Hall sensor alignment from perpendicular to magnetic field lines (conventional) to parallel alignment. This parameter change transforms the sensor's response characteristics, making it generate Hall voltage only when external ferromagnetic components alter the magnetic flux density, thereby optimizing sensitivity for specific measurement applications.

Inventive Principle:
Principle #35Parameter changes

2Length of stationary object

If the distance between the Hall sensor and permanent magnet is reduced, then the magnetic flux density increases, but the sensitivity to external ferromagnetic components may be compromised without proper geometric alignment

Engineering Contradiction:
Improvedistance between sensor and magnetVSAvoiddetection sensitivity
Core Design Contradiction:
Length of stationary objectVSMeasurement precision

Solution Approach 1:

The patent optimizes the distance parameter between the Hall sensor and permanent magnet to less than 10 mm (preferably less than 2 mm, most preferably less than 0.7 mm) and combines it with parallel geometric alignment. This parameter optimization ensures sufficient magnetic flux density while maintaining sensitivity to external ferromagnetic components through the specific alignment configuration.

Inventive Principle:
Principle #35Parameter changes

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 sensor's sensitivity and accuracy, enabling the detection of even slight changes in magnetic flux density and position of ferromagnetic components, with increased Hall voltage generation and improved detection accuracy.

Implementation Method 1

a Hall sensor (40) on the surface. The Hall sensor (40), which is preferably embodied as a Hall plate, has a main extension surface running parallel to the surface of the semiconductor body (30)

Methodology Applied
Scientific EffectHall effect: Hall Effect

Data Source

PatentEP2607857B1Integrated magnetic field sensor and method for measuring the position of a ferromagnetic workpiece with an integrated magnetic field sensor
Publication Date: 2018.07.25 TDK MICRONAS GMBH
  • EP2607857B1 patent drawingFigure 1~3

AI summary

The integrated magnetic field sensor (10) has a semiconductor body (30) with an upper surface and a rear surface. A surface (55) of a magnet (50) is formed perpendicular to a main extension surface of Hall sensor (40). A central axis (M) runs parallel to the main extension plane of the Hall sensor. The central axis passes in a perpendicular manner through a standard (N) of the main extension surface. The standard stands in a centroid of the main extension surface. The field lines of the magnet run parallel to the main extension surface of the Hall sensor such that a Hall voltage is generated, when a part of the magnetic field lines is deflected by a ferromagnetic component (100) perpendicular to the main extension plane of the Hall sensor. An independent claim is included for a method for a determining a position of a ferromagnetic component.