Magnetic Sensor Signal Correction for Oblique-Field Distortion
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Solution Overview
Problem
Magnetic sensors with magnetoresistive effect elements face distortion errors in signal output when external magnetic fields intersect the sensitivity axis obliquely, affecting linearity and accuracy in position detection devices.
Innovation Solution
A magnetic sensor with a signal correction unit that applies a correction value to reduce distortion errors using a formula (V′=V+V3×a) to stabilize the output signal, even when external magnetic fields intersect the sensitivity axis at various angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnetoresistive effect element is used to detect magnetic fields, then the sensor can detect magnetic field intensity, but distortion errors occur in the output signal when the magnetic field intersects the sensitivity axis obliquely
Solution Approach 1:
The patent applies parameter changes by introducing a correction coefficient 'a' that modifies the output signal based on the angle between the magnetic field and the sensitivity axis. The correction value is calculated as V³ × a, where V is the output signal and a is a pre-determined coefficient that compensates for distortion errors at oblique angles, thereby improving signal linearity across different measurement conditions.
2Adaptability or versatility
If the sensitivity axis is aligned with the external magnetic field, then accurate signal output is achieved, but the sensor cannot accurately detect magnetic fields intersecting at oblique angles
Solution Approach 1:
The patent implements feedback by using the output signal V itself to calculate the correction value. The correction is based on the cubic term V³ multiplied by a correction coefficient a, creating a feedback mechanism that automatically adjusts the signal based on its own magnitude and the detection conditions, enabling accurate measurement across various angles.
Solution Approach 2:
The patent changes the signal processing parameters by introducing angle-dependent correction terms. The correction value V³ × a varies with the angle between the magnetic field and sensitivity axis, allowing the sensor to compensate for oblique angle distortions and maintain measurement accuracy across a wider detection range.
3Measurement precision
If a correction value is applied to reduce distortion errors, then signal linearity improves, but the device complexity increases due to additional signal processing
Solution Approach 1:
The patent minimizes device complexity by using a simple parameter change approach. Instead of complex hardware modifications, the solution applies a mathematical correction to the output signal using a pre-determined correction coefficient 'a'. The correction value V³ × a can be implemented through simple multiplication operations in the signal processing circuit, avoiding the need for complex additional 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 solution improves the linearity and accuracy of the magnetic sensor's output signal by halving distortion errors, ensuring consistent performance regardless of the magnetic field direction.
Implementation Method 1
a magnetoresistive effect element (MR element) whose resistance changes according to the angle formed by the magnetization direction of the free layer in accordance with an external magnetic field with respect to the magnetization direction of the magnetization fixed layer
Data Source
AI summary
A magnetic sensor comprises a magnetic detection unit that outputs a signal by applying a magnetic field, and a signal correction unit that corrects the signal output from the magnetic detection unit. The magnetic detection unit includes a magnetoresistive effect element having a predetermined sensitivity axis. The signal correction unit generates a corrected signal by correcting the signal using a correction value capable of reducing the distortion error included in the signal output from the magnetic detection unit when the magnetic field having an intersecting direction that obliquely intersects the sensitivity axis is applied to the magnetoresistive effect element.