PCB-Mounted Coil Component With Recessed Electrodes for Adhesion
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Solution Overview
Problem
There is a need for a coil component with reduced thickness and enhanced adhesion strength to prevent movement or rotation when mounted on a printed circuit board (PCB), while simplifying manufacturing processes to decrease defect rates.
Innovation Solution
A coil component design featuring a body with a coil, external electrodes only on the lower surface, and via electrodes connecting the coil to the external electrodes, with recesses in the electrodes to increase solder contact area and improve adhesion, thereby enhancing the adhesion strength and reducing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If external electrodes are disposed only on the lower surface of the body, then the thickness of the coil component is reduced and manufacturing processes are simplified, but the adhesion strength when mounted on PCB may be weakened
Solution Approach 1:
The patent transitions from having external electrodes on both upper and lower surfaces to having them only on the lower surface, utilizing the vertical dimension strategically. This dimensional change reduces overall thickness and simplifies manufacturing while the recesses compensate for the reduced electrode surface area by increasing contact depth and surface area at the critical mounting interface.
Solution Approach 2:
The recesses created in the external electrodes function similarly to porous structures by increasing the effective surface area and providing mechanical interlocking features. These recesses allow solder to penetrate and create stronger bonds, compensating for the reduced electrode footprint caused by having electrodes on only one surface.
2Ease of manufacture
If external electrodes are disposed only on the lower surface of the body, then manufacturing processes are simplified, but the defect rate between processes may increase
Solution Approach 1:
The patent extracts the upper surface electrodes from the design, eliminating the need for complex multi-surface electrode formation processes. This extraction simplifies manufacturing by reducing the number of plating and patterning steps required, while the recesses in the lower surface electrodes maintain sufficient electrical and mechanical connection capability.
Solution Approach 2:
The patent changes the geometric parameters of the external electrodes by introducing recesses with specific depth and width ratios. These parameter changes optimize the balance between simplified manufacturing and reliable connections, ensuring that the reduced electrode configuration does not compromise product quality or increase defect rates.
3Stability of the object's composition
If adhesion strength is strengthened to prevent movement or rotation, then the coil component remains stable when mounted on PCB, but the manufacturing complexity increases
Solution Approach 1:
The recesses introduced in the external electrodes create curved or non-planar surfaces that increase mechanical interlocking with the solder and PCB. This geometric feature enhances stability by preventing movement and rotation, while the recesses can be formed using standard plating or etching processes, avoiding significant increases in manufacturing complexity.
Data Source
AI summary
A coil component includes a body, a coil disposed in the body, an external electrode disposed on one surface of the body and including at least one recess, and a via electrode disposed in the body and connecting the coil to the external electrode.