Magnetic Angle Sensor Ring Electrode Orientation
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Solution Overview
Problem
Existing magnetic sensors face challenges in accurately determining the orientation of a magnetic field component within a specific plane relative to a predetermined axis, particularly in rotary position sensing applications, as they often rely on orthogonal Hall elements that may not provide sufficient sensitivity and accuracy.
Innovation Solution
A magnetic angle sensor comprising a bulk substrate with a circular well and an even-numbered plurality of electrodes in a ring formation, where a progressive succession of differently directed bias currents is applied to generate Hall potentials, allowing for the determination of the orientation of magnetic field components in a plane, with the sensor operating cyclically to cover a complete rotation and analyze output signals to determine the orientation relative to a predefined axis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If orthogonal Hall elements are used to determine magnetic field orientation, then the sensor can detect magnetic field components in two perpendicular directions, but the sensitivity and accuracy for determining the orientation angle are insufficient
Solution Approach 1:
The sensor divides the circular well into multiple segments by placing multiple electrodes (at least three) around the circumference at regular intervals. This segmentation allows the sensor to measure magnetic field orientation by detecting Hall potentials at different angular positions, improving measurement precision without requiring complex multi-element structures.
Solution Approach 2:
The patent transitions from measuring only two perpendicular components (x and y directions) using orthogonal Hall elements to measuring the full circular orientation by adding the angular dimension. The electrodes are arranged around the circumference of the circular well, enabling measurement of the magnetic field orientation angle θ in the plane, which provides complete directional information.
2Measurement precision
If a circular well with multiple electrodes is used to improve orientation sensing accuracy, then the sensor can determine magnetic field orientation in a plane, but the device complexity increases
Solution Approach 1:
The circular well structure serves multiple functions: it provides the active region for Hall effect measurement, defines the geometric arrangement for multiple electrodes, and establishes the reference frame for angular measurement. The electrodes serve dual purposes as both current injection points and potential sensing points, reducing the need for separate components.
Solution Approach 2:
The patent changes the geometric parameter arrangement from linear orthogonal axes to circular angular coordinates. By placing electrodes at regular angular intervals around the circular well, the sensor transforms the measurement space from Cartesian coordinates to polar coordinates, enabling direct measurement of orientation angle while maintaining manufacturing simplicity through rotational symmetry.
3Measurement precision
If the well is made sufficiently deep to generate Hall potential, then accurate sensing is achieved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies partial action by making the well depth sufficient only to the extent necessary to generate adequate Hall potential, rather than excessively deep. The well depth is optimized to achieve the minimum required for effective Hall effect while avoiding over-engineering that would increase manufacturing complexity and cost.
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 enhances the accuracy and sensitivity of magnetic field orientation sensing, enabling precise determination of the angle of rotation and orientation of a magnetic field component within a plane, with improved interpolation and reduced manufacturing tolerances' impact, achieving sinusoidal output signals and phase analysis for precise axis alignment.
Implementation Method 1
a bulk substrate; a circular well provided upon the bulk substrate; an even numbered plurality of electrodes spaced at regular intervals in a ring formation over the circular well... means for selectively applying a progressive succession of differently directed bias currents to and/or using the said ring of electrodes to provide a succession of Hall potentials
Data Source
Figure 1a~1b
Figure 2(a)~3
Figure 4(a)~5
AI summary
A magnetic angle sensor 100 comprises a bulk substrate; a circular well 101 provided upon the bulk substrate; an even numbered plurality of electrodes 102a- 102x spaced at regular intervals in a ring formation over the circular well; and means for selectively applying a progressive succession of differently directed bias currents 104 to and/or using the said ring of electrodes 102 to provide a succession of Hall potentials indicative of the relative magnitude of successive differently oriented magnetic field components B in the plane of the magnetic angle sensor 100. The sensor 100 operates cyclically and the full progressive succession cycle involves applying and/or using each electrode 102 in the ring at least once for applying a bias current and/or sensing a Hall potential. In such a manner, the full cycle comprises the progressive succession of the axis of measurement of the sensor 100 through a complete rotation within the plane of the sensor. By monitoring the phase of the generated signal or monitoring the zero crossings of the generated signal the orientation of the magnetic field coin the plane of the sensor can be determined.