Coil Terminal Electrode Structure for Visible Solder Fillets
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Solution Overview
Problem
Existing wire-wound coil components face challenges in forming recognizable solder fillets during inspection, as terminal electrodes with increased height risk electrical connection, hindering automated optical inspection and potentially leading to faulty mounting.
Innovation Solution
A coil component design featuring a drum-shaped core with flange portions and terminal electrodes that include a base electrode and plating layer, where the drum-shaped core is moved back and forth to increase the height of the end-surface base electrode portion beyond the crotch height, facilitating higher and more recognizable solder fillets during mounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the height of terminal electrodes is increased to form recognizable solder fillets for inspection, then the visibility of solder fillets is improved, but the risk of electrical connection between terminal electrodes increases
Solution Approach 1:
The terminal electrode is segmented into two distinct parts: a base electrode portion formed on the bottom surface and a plating electrode portion covering other surfaces. This segmentation allows different height configurations for different portions, enabling the end-surface base electrode portion to extend above the crotch height for fillet visibility while keeping side-surface base electrode portions below the crotch height to prevent electrical connection.
Solution Approach 2:
Different portions of the terminal electrode are given different local qualities in terms of height. The end-surface base electrode portion has a greater height than the crotch height to improve fillet recognition, while the side-surface base electrode portion has a lesser height than the crotch height to maintain insulation. This local differentiation resolves the contradiction between visibility and electrical safety.
2Difficulty of detecting and measuring
If the height of terminal electrodes is increased to facilitate automated optical inspection, then the ease of detection is improved, but the device complexity increases due to multi-step manufacturing process
Solution Approach 1:
The base electrode is formed first on the bottom surface with the required height configuration, and then the plating electrode is formed to cover the remaining surfaces. This preliminary action of forming the base electrode with the correct height before plating simplifies the overall process compared to forming the complete terminal electrode and then selectively removing material to achieve the height differential.
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 enhances the visibility of solder fillets for automated inspection, preventing electrical connections between terminal electrodes and ensuring reliable mounting, while maintaining insulation and reducing thermal shock resistance variations.
Implementation Method 1
The first terminal electrode and the second terminal electrode each include a base electrode formed on a surface of the first flange portion and a plating layer that covers the base electrode
Data Source
AI summary
A coil component includes a drum-shaped core including a core portion that extends in a length direction of the coil component and a first flange portion provided on a first end portion of the core portion, and first and second terminal electrodes provided on the first flange portion. The first and second terminal electrodes each include a base electrode formed on a surface of the first flange portion and a plating layer that covers the base electrode. The base electrode includes a bottom-surface base electrode portion on a bottom surface, an end-surface base electrode portion on an end surface, and a side-surface base electrode portion on a first side surface. The end-surface base electrode portion has a height greater than that of the first crotch portion. The side-surface base electrode portion has a height less than that of the first crotch portion.