Non-Magnetic Terminal Electrodes for MRI Winding Inductors
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Solution Overview
Problem
Nickel-based terminal electrodes in winding inductor components react with strong magnetic fields, causing disturbances in the surrounding magnetic field, particularly in applications like MRI, which can lead to image quality issues.
Innovation Solution
The use of non-magnetic terminal electrodes made from materials like silver and tin, integrated with a core having a columnar shaft and support portions, reduces the reaction with magnetic fields by eliminating magnetic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nickel-based terminal electrodes are used for thermal compression bonding, then manufacturing cost is reduced and bonding reliability is improved, but magnetic field disturbance occurs in strong magnetic field environments
Solution Approach 1:
The patent changes the material parameter of the terminal electrodes from magnetic (nickel) to non-magnetic materials. The terminal electrodes are made of non-magnetic materials such as copper, copper alloys, aluminum, or aluminum alloys, which fundamentally alter the magnetic properties of the component while maintaining electrical conductivity and bonding capabilities.
Solution Approach 2:
The patent employs composite electrode structures combining multiple material layers. Specifically, it uses a copper electrode layer as the base material and applies a nickel plating layer only on the surface where wire bonding occurs. This composite structure provides both non-magnetic properties in the magnetic field environment and effective thermal compression bonding at the contact interface.
2Reliability
If nickel plating is applied on terminal electrodes to prevent melting during thermal compression bonding, then bonding process reliability is improved, but nickel reacts with magnetic fields causing image quality degradation in MRI applications
Solution Approach 1:
The patent applies the nickel plating layer only locally on the surface of the copper electrode where wire bonding occurs, rather than coating the entire terminal electrode. This localized approach maintains bonding reliability at the contact interface while minimizing the volume of nickel material that could react with magnetic fields.
Solution Approach 2:
The patent uses a thin nickel plating layer that serves its bonding function and then effectively becomes part of the bonded structure. The nickel layer is applied only where needed for bonding and does not extend to areas exposed to magnetic fields, reducing harmful interactions.
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 design effectively suppresses disturbances in the surrounding magnetic field, preventing image quality degradation and maintaining the Q value of the inductor component, while improving heat resistance and mounting reliability.
Implementation Method 1
since the terminal electrodes are non-magnetic bodies, it is possible to suppress reaction of the terminal electrodes with a surrounding magnetic field
Data Source
AI summary
A winding inductor component includes a core having a columnar shaft portion and a pair of support portions provided at both ends of the shaft portion. The wiring inductor component further includes terminal electrodes provided on the pair of support portions, respectively, and being non-magnetic bodies, and a wire wound around the shaft portion and having both end portions connected to the terminal electrodes of the pair of support portions.