Coil Device Terminal Electrode Buffer Layer
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Solution Overview
Problem
Conventional coil devices with general terminal electrode structures are prone to releasing and breaking due to heat stress and impact, lacking sufficient heat stress resistance and impact resistance.
Innovation Solution
A coil device with a core body and a coil part forming a spiral conductive pathway, where a metal electrode is formed on the core's outer face and partially covered by a conductive resin electrode, acting as a buffer layer when mounted on a substrate, enhancing stress relief and connection resilience through thermocompression bonding and coating films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a general terminal electrode structure with metal electrode is used, then the coil device can be mounted on substrate, but the metal electrode and core are prone to releasing and breaking due to heat stress and impact
Solution Approach 1:
The patent applies composite materials by combining metal electrode with conductive resin electrode to create a terminal electrode structure that leverages the advantages of both materials. The metal electrode provides electrical conductivity and mechanical strength, while the conductive resin electrode provides stress absorption and flexibility, preventing breaking under heat stress and impact.
Solution Approach 2:
The conductive resin electrode acts as an intermediary layer between the metal electrode and the substrate. This intermediate layer absorbs thermal expansion differences and mechanical stress, preventing direct stress transmission to the metal electrode and core, thereby preventing releasing and breaking.
2Reliability
If the metal electrode surface is fully covered by conductive resin electrode, then stress relief is improved, but thermocompression bonding of lead part becomes difficult
Solution Approach 1:
The patent applies local quality by creating different surface regions on the terminal electrode: one region covered by conductive resin electrode for stress relief and mounting, and another region with exposed metal electrode surface for thermocompression bonding. This localized differentiation allows each region to perform its specific function optimally.
3Adaptability or versatility
If the coil device is designed for wide temperature range operation, then environmental adaptability is improved, but material selection and construction complexity increases
Solution Approach 1:
The patent applies parameter changes by selecting materials with appropriate thermal expansion coefficients and electrical conductivity properties that remain stable across the wide temperature range of -55 to 150°C. The conductive resin electrode's composition is optimized to maintain its stress-absorbing properties throughout this temperature range.
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 coil device exhibits improved heat stress resistance and impact resistance, allowing operation in a wide temperature range (-55 to 150°C) and withstanding harsh environments, including constant vibration, while maintaining electrical and mechanical connections.
Implementation Method 1
the conductive resin electrode functions as the buffer layer between the coil device and the substrate, thereby the stress caused by the heat stress and impact is relieved
Implementation Method 2
the lead part can be connected to the surface of the metal electrode by thermocompression bonding or so
Data Source
AI summary
A coil device comprising, the core body having a coil core part and a core bottom face, and a coil part forming spiral conductive pathway around the coil core part. A metal electrode is formed at the core bottom face, and the wire ends which are the conductive pathway of the coil part are formed at the metal electrode, and a part of the surface of the metal electrode is covered by the conductive resin electrode.