Annular PCB Land Pattern Layout to Prevent Closed Solder Voids
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Solution Overview
Problem
When a circuit board's conductor patterns with an annular structure are exposed without solder resist, the space surrounded by annular solder can close, leading to issues like corrosion, gas accumulation, and unreliable connections due to solder failure.
Innovation Solution
The conductor pattern design includes specific configurations such as wider or protruding connection sections and/or annular openings to prevent the formation of closed spaces by reducing the solder amount per unit area, ensuring reliable connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the solder resist is omitted to thin the circuit board, then the circuit board thickness is reduced, but closed spaces may form around annular conductor patterns causing connection failures
Solution Approach 1:
The connection part has non-uniform width with a third section wider than the first and second sections. This local variation in width creates different solder flow characteristics in different regions, preventing closed space formation while maintaining the exposed conductor pattern structure.
Solution Approach 2:
The connection part is divided into multiple sections (first section, second section, and third section) with different width characteristics. This segmentation allows each section to control solder flow differently, ensuring solder can escape through the wider third section while maintaining connection integrity.
2Ease of manufacture
If the conductor pattern is exposed without solder resist, then manufacturing is simplified and thickness is reduced, but solder may flow into unintended areas causing closed spaces
Solution Approach 1:
The connection part features localized width variations with the third section being wider than the first and second sections. This creates specific solder flow paths and pressure distribution that prevent solder from entering unintended areas while maintaining the exposed pattern structure.
Solution Approach 2:
The potential harmful effect of solder flowing into the annular conductor pattern is converted into a beneficial feature by designing the third section to be wider. This controlled solder flow path allows solder to escape through the wider section rather than forming closed spaces, transforming the potential defect into a design feature.
Data Source
AI summary
Disclosed herein is a circuit board in which a conductor pattern having an annular structure is exposed to the surface thereof. The conductor pattern includes first and second land pattern parts and a first connection part connecting the first and second land pattern parts. The first connection part includes a first section connected to the first land pattern part, a second section connected to the second land pattern part, and a third section connecting the first and second sections. At least a part of the third section of the first connection part is larger in width than the first and section sections.