Coil Wire Bonding Structure to Prevent Breakage at Outer Electrodes
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Solution Overview
Problem
The existing coil components face wire breakage issues due to external forces concentrating on thinned wire portions after thermocompression bonding, leading to potential wire failure.
Innovation Solution
A coil component design featuring a column-like winding core with flanges and outer electrodes, where wire ends are formed into ball portions with diameters greater than the body portion, and bonded using a laser beam while in contact with the outer electrodes, creating thicker bonded portions that reduce the likelihood of breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermocompression bonding is used to bond wire ends to outer electrodes, then electrical connection is achieved, but the wire becomes flattened and thinned leading to breakage under external forces
Solution Approach 1:
The patent changes the bonding method from thermocompression bonding to laser beam bonding, which fundamentally alters the physical and chemical parameters of the bonding process. Laser bonding creates a molten pool that forms a stronger metallurgical bond without flattening the wire, thereby maintaining wire strength while achieving reliable electrical connection
Solution Approach 2:
The patent replaces the mechanical thermocompression bonding system with a laser-based energy field system. Instead of applying mechanical pressure and heat through a heater chip, the laser beam delivers concentrated optical energy to melt and bond the wire, eliminating the wire-thinning effect caused by mechanical compression
2Ease of manufacture
If wire ends are flattened through thermocompression bonding, then bonding to outer electrode is achieved, but external forces concentrate on thinned portion causing wire breakage
Solution Approach 1:
The patent replaces mechanical compression bonding with laser beam bonding, substituting a mechanical process with an optical energy-based process. This eliminates wire flattening while maintaining bonding effectiveness, thereby improving reliability without significantly complicating the manufacturing process
Solution Approach 2:
The bonding parameters are fundamentally changed from mechanical pressure and temperature to laser power, scanning speed, and focal position. These parameter changes enable bonding without wire deformation, resolving the contradiction between ease of manufacture and wire reliability
3Strength
If ball portion diameter is increased to prevent wire breakage, then wire strength is improved, but manufacturing complexity increases
Solution Approach 1:
The patent uses laser beam bonding to naturally form spherical ball portions through controlled melting. The laser's concentrated energy creates a molten pool that solidifies into a sphere, achieving the desired geometry through physics rather than complex mechanical forming equipment
Solution Approach 2:
The patent utilizes the phase transition of wire material from solid to liquid and back to solid under laser heating. This controlled melting and solidification process naturally forms spherical ball portions with increased diameter, achieving strength improvement through material phase change rather than mechanical deformation
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 increased thickness of bonded portions prevents wire breakage under external forces and enhances contact area with outer electrodes, reducing the likelihood of wire detachment and improving electrical connections.
Implementation Method 1
a ball forming step of forming a ball portion by melting the wire at each end of the wire, the ball portion having a diameter greater than that of a body portion of the wire before melting the wire
Implementation Method 2
a bonding step of forming a bonded portion at each end of the wire. The bonded portion is bonded to an outer electrode that covers an outer surface of a core, in such a manner that the ball portion is irradiated with a laser beam while the ball portion is in contact with the outer electrode
Data Source
AI summary
A coil component includes a core, a wire, and outer electrodes. The core includes a winding core and a pair of flanges. A first axis orthogonally intersects a central axis. A first positive direction is a direction directed toward one side along the first axis. A first negative direction is directed oppositely to the first positive direction. Each outer electrode covers a surface of each flange, the surface facing in the first positive direction. The wire includes a body portion wound around the winding core and a bonded portion at each end of the wire and coupled to each outer electrode. In a cross section that orthogonally intersects the central axis and includes the bonded portion, the end of the bonded portion facing in the first negative direction is further in the first negative direction from the end of the outer electrode facing in the first positive direction.