Coil Component Insulating Film Segmentation for Reflow Reliability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing coil components face issues with insulating films breaking or peeling off during reflow due to the interposition of low-melting-point metal films between the conductor and insulating films, leading to electrical short-circuits and reliability concerns.
Innovation Solution
A coil component design featuring a conductor plate with a metal element body and terminal parts, where the body part is covered with an insulating film without a metal film interposed, and the terminal parts have a metal film with a lower melting point, ensuring electrical insulation and preventing film damage during reflow. The magnetic core has a through hole with a conductivity material and cut parts to house the terminal parts, enhancing the component's reliability and preventing short-circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a metal film having a low melting point is formed on the surface of the conductor plate to ensure solder wettability, then solder wettability is improved, but the insulating film may be broken or peeled off during reflow
Solution Approach 1:
The conductor plate surface is segmented into two distinct regions: the body part covered with insulating film for electrical insulation, and the terminal part covered with low-melting-point metal film for solder wettability. This spatial segmentation allows each region to fulfill its specific function without interfering with the other, preventing insulating film damage during reflow while ensuring proper soldering at terminals.
Solution Approach 2:
Different surface treatments are applied to different locations of the conductor plate based on local functional requirements. The body part requires insulating properties to prevent short circuits with the magnetic core, while the terminal part requires solderable properties for mounting. This local differentiation of material properties resolves the contradiction between insulation and soldering requirements.
2Reliability
If an insulating film is formed on the conductor plate surface to prevent electrical short-circuit with the magnetic core, then electrical insulation is improved, but the insulating film may be broken or peeled off during reflow when a metal film is interposed
Solution Approach 1:
The conductor plate surface is segmented into two distinct regions: the body part covered with insulating film for electrical insulation, and the terminal part covered with low-melting-point metal film for solder wettability. This spatial segmentation allows each region to fulfill its specific function without interfering with the other, preventing insulating film damage during reflow while ensuring proper soldering at terminals.
Solution Approach 2:
The insulating film acts as an intermediary layer between the conductor plate body and the magnetic core, preventing direct contact and electrical short-circuit. By positioning this intermediary layer only where needed (body part), the design maintains electrical insulation while avoiding the harmful interaction between metal film and insulating film that occurs during reflow.
3Reliability
If a magnetic material having conductivity like MnZn-based material is used to achieve higher magnetic characteristics, then magnetic properties are improved, but the conductor plate and magnetic core need to be electrically insulated
Solution Approach 1:
Different surface treatments are applied to different locations of the conductor plate based on local functional requirements. The body part requires insulating properties to prevent short circuits with the magnetic core, while the terminal part requires solderable properties for mounting. This local differentiation of material properties resolves the contradiction between insulation and soldering requirements.
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 configuration effectively prevents insulating film breakdown and short-circuits during reflow, ensuring a highly reliable coil component with improved magnetic characteristics and solder wettability, while maintaining the magnetic core's volume and facilitating mounting on circuit boards.
Implementation Method 1
the body part of the metal element body positioned inside the through hole is covered with the insulating film, preventing the magnetic core having conductivity and metal element body from being electrically short-circuited
Implementation Method 2
a metal film, such as a tin-plated film, made of metal having a low melting point needs to be formed on the surface of the conductor plate
Data Source
AI summary
Disclosed herein is a coil component that includes a conductor plate; and a magnetic core comprising a magnetic material having conductivity, the magnetic core having a through hole into which the conductor plate is inserted. The conductor plate includes: a metal element body having a body part positioned inside the through hole and a terminal part positioned outside the through hole; a metal film formed on the terminal part, the metal film comprising a metal material having a lower melting point than the metal element body; and an insulating film formed on a surface of the body part without the metal film interposed.