Circuit Board Bleed Prevention Pattern Design
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Solution Overview
Problem
In the miniaturization of electronic devices, the protective material used on flexible circuit boards tends to bleed into the inner lead region where chips are mounted, interfering with connections and deteriorating the quality of the circuit board.
Innovation Solution
A circuit board design featuring a bleed prevention pattern on the base substrate, which is formed in a protruding pattern around the protective layer formation region to prevent the protective material from flowing beyond its intended area, including an accommodating portion to store excess material and prevent penetration into the inner lead region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective layer is formed using ink-type protective material, then the wiring pattern is protected from damage, but the protective material bleeds to surrounding areas including the inner lead region
Solution Approach 1:
A bleed prevention pattern is introduced as an intermediary structure between the protective layer formation region and the inner lead region. This pattern acts as a barrier that prevents the protective material from bleeding into the inner lead region while allowing the protective layer to form properly over the wiring pattern.
Solution Approach 2:
The base substrate is segmented into distinct regions: a protective layer formation region, an inner lead region, and a bleed prevention pattern region. This segmentation creates physical boundaries that control the flow and distribution of the protective material, preventing it from spreading into unwanted areas.
2Reliability
If the protective material is applied generously to ensure complete coverage, then protection effectiveness increases, but bleeding to other regions worsens
Solution Approach 1:
The bleed prevention pattern serves as a mediator that allows generous application of protective material without compromising boundary control. The pattern absorbs or blocks excess material, enabling complete coverage of the wiring pattern while maintaining precise boundaries at the interface with the inner lead region.
Data Source
AI summary
A circuit board includes: a base substrate in which a protective layer formation region is defined; a wiring pattern which is formed on the base substrate and which has at least a portion formed in the protective layer formation region; a protective layer fixed onto the protective layer formation region and formed of a protective material; and a bleed prevention pattern formed on the base substrate so as to prevent the protective material from flowing beyond the protective layer formation region when the protective layer is formed.