AMR GMR Sensor Linearity via Anisotropic Layer Strips
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Solution Overview
Problem
Magneto-resistive sensors employing the anisotropic magneto-resistive (AMR) or gigantic magneto-resistive (GMR) effects face challenges with non-linearity and temperature dependence, making them inadequate for various applications, and existing solutions are either complex or economically unfeasible.
Innovation Solution
The implementation of a sensor arrangement with resistors formed from layer strips in a half or full bridge circuit, where at least one resistor includes magneto-resistive layer strips with different shape anisotropy and additional layer strips with different temperature coefficients, connected in series to achieve a linear characteristic curve and temperature-independent output signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magneto-resistive layer strips with different shape anisotropy are used in the bridge circuit, then linearity of the characteristic curve is improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by using magneto-resistive layer strips with different shape anisotropy in specific positions of the bridge circuit. Specifically, at least one resistor in the half or full bridge circuit contains layer strips with different shape anisotropy, while other resistors may use standard strips. This localized differentiation linearizes the characteristic curve without requiring all components to be complex, thus resolving the contradiction between measurement precision and device complexity.
2Stability of the object's composition
If additional layer strips with different temperature coefficients are connected in series, then temperature independence of output signal is improved, but device complexity increases
Solution Approach 1:
The patent employs composite materials by combining magneto-resistive layer strips with additional layer strips that have different temperature coefficients of resistance. These composite resistor structures are integrated into the bridge circuit, where the different temperature coefficients compensate for each other, achieving temperature-independent output signals. This approach improves temperature stability while managing the increase in device complexity through material-level integration rather than separate compensation circuits.
3Measurement precision
If magneto-resistive layer strips with different shape anisotropy are used, then linear characteristic curve is achieved, but sensor area increases
Solution Approach 1:
The patent applies parameter changes by utilizing layer strips with different shape anisotropy parameters to achieve linearization of the characteristic curve. By carefully selecting and combining strips with specific anisotropy characteristics, the patent achieves linearity without proportionally increasing the total sensor area. The different shape anisotropy parameters allow for optimized spatial arrangement that maintains compact sensor footprint while achieving the desired linear response.
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 approach results in a sensor with a linear characteristic curve and temperature-stabilized output, minimizing sensor surface area and increasing sensitivity, while maintaining a stable resistance value across magnetic fields and temperatures.
Implementation Method 1
The invention is directed to sensors which employ either the anisotropic magneto-resistive effect (AMR) or the gigantic magneto-resistive effect (GMR) and are suitable for indicating magnetic fields
Implementation Method 2
The invention is directed to sensors which employ either the anisotropic magneto-resistive effect (AMR) or the gigantic magneto-resistive effect (GMR) and are suitable for indicating magnetic fields
Implementation Method 3
The temperature dependence of the output signal of the magneto-resistive sensors can be eliminated according to the document GB 2 281 654 by applying a thermometer layer on the substrate directly underneath the magneto-resistive layer
Data Source
AI summary
Magnetoresistive sensors based on the AMR or GMR effect exhibit substantially enlarged linear characteristic curve regions as a result of the fact that their resistances are composed of magnetoresistive layer strips of differing anisotropic forms. Differing anisotropic forms can be achieved by different strip widths, strip thicknesses, strip intervals or strip materials. The temperature compensation for the output voltage of the magnetoresistive sensors, at least at one point on the characteristic curve, is achieved by the series connection of an additional layer strip with a temperature coefficient that differs from that of the magnetoresistive material to at least one magnetoresistive resistance of the sensor.