Coil Component Terminal Electrode Surface Roughness
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Solution Overview
Problem
Existing coil components with embedded wire-shaped coil conductors in magnetic elements face challenges in ensuring high reliability for connections between the coil conductor and conductive resin, as electrical conduction is primarily through physical contact, which is less reliable compared to metal bonding between conductive resin and plating films.
Innovation Solution
A coil component design where the end portion of the coil conductor has an exposed surface with increased surface roughness for improved contact with conductive resin, and a manufacturing method involving a resin coating, laser irradiation to roughen the surface, and a metal film formation to enhance electrical conductivity and bonding, using conductive resins with varying particle sizes for optimized contact and bonding strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a pasty conductive resin is applied on the surface of the magnetic element body to contact the end portion of the coil conductor, then it is possible to easily form the terminal electrode on the surface of the magnetic element body from which the coil conductor is not exposed, but high reliability is more difficult to ensure for the connection between the conductive resin and the coil conductor compared to the connection between the conductive resin and the plating film
Solution Approach 1:
The patent applies surface roughening treatment to the exposed surface of the coil conductor end portion, changing the surface topology parameter from smooth to rough. This increases the contact area and mechanical interlocking between the conductive resin and coil conductor, thereby improving connection reliability while maintaining the ease of terminal electrode formation on the magnetic element body surface.
Solution Approach 2:
The patent performs surface roughening treatment on the coil conductor end portion before applying the conductive resin. This preliminary action prepares the surface with enhanced roughness to ensure better adhesion and electrical contact, addressing the reliability issue before the bonding process occurs.
2Device complexity
If the terminal electrode is directly formed by plating on the end portion of the coil conductor, then the manufacturing process is simplified, but it is difficult to form the terminal electrode on the surface of the magnetic element body from which the coil conductor is not exposed
Solution Approach 1:
The patent introduces conductive resin as an intermediary material between the coil conductor and the plating film. This intermediary enables the formation of terminal electrodes on the magnetic element body surface even when the coil conductor is not exposed, as the conductive resin can be applied to contact the conductor end portion and extend to the required surface locations.
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 significantly improves the connection reliability between the coil conductor and conductive resin by increasing the contact area and bonding strength, reducing resistance values, and preventing unintended contact between conductive magnetic materials and the resin.
Implementation Method 1
the exposed surface has a larger surface roughness than the non-exposed surface
Data Source
AI summary
Disclosed herein is a coil component that includes a magnetic element body, a coil conductor embedded in the magnetic element body and having an end portion exposed from the magnetic element body, and a terminal electrode connected to the end portion of the coil conductor. The terminal electrode includes a conductive resin contacting the end portion of the coil conductor and containing conductive particles and a resin material, and a metal film covering the conductive resin. The end portion of the coil conductor has an exposed surface exposed from the magnetic element body and contacting the conductive resin and a non-exposed surface covered with the magnetic element body. The exposed surface is larger in surface roughness than the non-exposed surface.