PCB Frame Ground Oxidation Prevention via Solder Resist Through-Holes
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Solution Overview
Problem
Conventional frame ground technologies in small electronic devices face issues with copper foil oxidation during high-temperature conditions, leading to conduction failure, and existing solutions like gold plating are expensive and hinder size reduction in lightweight designs.
Innovation Solution
A printed circuit board design featuring conductor patterns around board-fixation holes with multiple through-holes that allow a minimal amount of solder to flow and form a protective film, reducing the thickness of the frame ground while preventing oxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gold plating is applied to the pad surface to prevent oxidation, then the frame ground connection reliability is improved, but the manufacturing cost increases
Solution Approach 1:
The patent replaces expensive gold plating with a cheaper alternative: a copper foil pad covered by a solder resist film with through-holes. The solder that flows through these holes provides the protective function at lower cost, effectively using a less expensive material to achieve the same oxidation prevention purpose.
Solution Approach 2:
The solder resist film is designed with through-holes (porous structure) that allow solder to flow through and contact the copper foil pad. This porous design enables the solder to reach and protect the copper surface without requiring expensive gold plating, while still maintaining oxidation prevention functionality.
2Reliability
If mounds of solder are applied to the copper foil pad to prevent oxidation, then the frame ground connection reliability is improved, but the frame ground thickness increases
Solution Approach 1:
The patent uses a thin solder resist film with through-holes instead of thick mounds of solder. The film structure allows solder to flow through in a controlled manner, creating a thin protective layer rather than thick solder mounds, thereby maintaining reliability while reducing thickness.
Solution Approach 2:
Instead of applying solder uniformly across the entire copper foil pad surface (which would create thick mounds), the patent uses through-holes to localize solder flow to specific points. This creates localized solder contact that provides oxidation protection without increasing overall frame ground thickness.
3Reliability
If a screw is inserted through the board-fixation hole to contact solder mounds, then the ground connection is maintained, but the device size and weight increase
Solution Approach 1:
The patent merges the ground connection function with the board-fixation hole structure. The through-holes in the solder resist film allow solder to flow through and create electrical contact between the copper foil pad and the metal frame, combining the mechanical fixation and electrical grounding functions in a single integrated structure without requiring separate screw components.
Solution Approach 2:
The patent extracts the solder connection function from the traditional screw-based mechanical connection. Instead of using a screw to physically contact and ground the copper pad, the design allows solder to flow through the through-holes and create the electrical connection, eliminating the need for additional screw components and reducing weight.
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 design minimizes the thickness of the frame ground while maintaining a reliable connection, reducing manufacturing costs and enabling smaller, thinner device designs by regulating the solder quantity and thickness.
Implementation Method 1
a solder film is formed around each of the through-holes on the copper foil land, thereby enabling a thin frame ground to be formed while a satisfactory ground connection is maintained in the frame ground
Implementation Method 2
a plurality of through-holes which are entry channels for molten solder are formed in each of the copper foil lands
Data Source
AI summary
According to one embodiment, there is provided a printed circuit board, including a frame ground portion in which conductor patterns are formed around a board-fixation hole, and a plurality of through-holes formed around the board-fixation hole in the frame ground portion.