Magnetic Sensor Eliminating Capacitive Effects
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Solution Overview
Problem
Magnetic sensors with an insulating layer between the sensitive element and the thin-film magnet exhibit reduced impedance change in response to magnetic field changes due to capacitive effects from high-frequency electric current.
Innovation Solution
A magnetic sensor design featuring a nonmagnetic substrate with a sensitive element made of soft magnetic material and pair of thin-film magnets facing each other, along with yokes to induce magnetic flux through the sensitive element, eliminating the need for an insulating layer and enhancing impedance change sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an insulating layer is interposed between the sensitive element and the thin-film magnet, then electrical insulation is provided, but the impedance change in response to magnetic field changes is reduced due to capacitive effects
Solution Approach 1:
A nonmagnetic conductive layer is introduced as an intermediary between the sensitive element and the thin-film magnet. This layer provides the necessary electrical insulation while maintaining magnetic flux penetration, thereby preserving both electrical insulation and impedance change sensitivity without the capacitive effects that would result from an insulating layer.
Solution Approach 2:
The patent changes the material parameter of the intermediate layer from insulating to conductive (nonmagnetic conductive material). This parameter change eliminates the capacitive effect while maintaining electrical insulation through the conductive layer's design, thereby preserving the impedance change sensitivity required for accurate magnetic field measurement.
2Object-generated harmful factors
If an insulating layer is used between the sensitive element and thin-film magnet, then electrical isolation is achieved, but the amount of impedance change as a function of magnetic field change is reduced
Solution Approach 1:
The nonmagnetic conductive layer serves as a mediator that eliminates the harmful capacitive effect by providing a conductive path that prevents charge accumulation, while still allowing magnetic flux to pass through to the sensitive element, thereby maintaining large impedance change magnitude.
Solution Approach 2:
The patent converts the potential harm of direct contact (short circuit risk) into a benefit by using a conductive layer that actively prevents capacitive effects while maintaining electrical isolation. The conductive layer transforms the insulation requirement from a potential source of capacitive interference into a controlled interface that enhances measurement precision.
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 design achieves a significant impedance change in response to magnetic field changes, improving sensitivity and eliminating capacitive effects from high-frequency electric current.
Implementation Method 1
the sensitive element being configured to sense a magnetic field by a magnetic impedance effect
Implementation Method 2
the pair of thin-film magnets being configured to apply a magnetic field in the longitudinal direction of the sensitive element
Implementation Method 3
the pair of yokes being configured to induce magnetic flux generated by the pair of thin-film magnets such that the magnetic flux passes through the sensitive element
Implementation Method 4
each of the pair of yokes being disposed between the sensitive element and a corresponding one of the pair of thin-film magnets, the pair of yokes being configured to induce magnetic flux generated by the pair of thin-film magnets such that the magnetic flux passes through the sensitive element
Data Source
AI summary
A magnetic sensor 1 includes: a nonmagnetic substrate 10; a sensitive element 31 laminated on the substrate 10, the sensitive element 31 being made of a soft magnetic material, the sensitive element 31 having a longitudinal direction and a transverse direction and having uniaxial magnetic anisotropy in a direction intersecting the longitudinal direction, the sensitive element 31 being configured to sense a magnetic field by a magnetic impedance effect; and a pair of thin-film magnets 20a, 20b laminated on the substrate 10 and disposed to face each other in the longitudinal direction across the sensitive element 31, the pair of thin-film magnets 20a, 20b being configured to apply a magnetic field in the longitudinal direction of the sensitive element 31.