Flexible Wiring Board Cover Lay Alignment for Accurate Terminal Openings
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Solution Overview
Problem
Existing methods for manufacturing flexible printed circuit boards (FPCs) face challenges in accurately aligning cover lay film openings with terminals due to the difficulty in handling long, thin, and soft cover lay films, leading to inaccuracies and reduced productivity.
Innovation Solution
A method involving a base material with laminated wiring, a cover lay with a protection layer and adhesive layer, and burrs, where a release layer is used to expose terminals with high positional accuracy by peeling off only the release layer in specific portions, allowing precise terminal formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a long cover lay film is used to manufacture long FPC, then the length of the FPC is increased, but the handling difficulty increases and dimensional variation increases
Solution Approach 1:
The invention divides the long cover lay film into multiple sections, each with its own positioning holes and positioning pins. This segmentation allows each section to be handled and positioned independently, reducing the overall handling difficulty while maintaining the ability to manufacture long FPCs.
Solution Approach 2:
Positioning holes are pre-formed in the cover lay film at specific intervals before the lamination process. This preliminary action enables accurate positioning to be achieved without requiring complex alignment procedures during manufacturing, thereby reducing handling difficulty.
2Length of moving object
If a long cover lay film is used to manufacture long FPC, then the length of the FPC is increased, but the dimensional variation increases
Solution Approach 1:
By dividing the long cover lay film into multiple sections with intermediate positioning points, the invention reduces the cumulative dimensional variation that would occur in a single continuous piece. Each section can be positioned and secured independently, maintaining manufacturing precision across the entire length.
Solution Approach 2:
The invention introduces positioning pins as intermediary elements that bridge the cover lay film and the base film at multiple points along the length. These intermediaries ensure accurate positioning and reduce dimensional variation by providing multiple reference points rather than relying on a single alignment.
3Ease of manufacture
If positioning pins are inserted into positioning holes to align cover lay film openings with terminals, then terminal formation is enabled, but alignment accuracy is insufficient for long FPCs
Solution Approach 1:
The invention uses multiple positioning holes and positioning pins distributed along the length of the cover lay film rather than a single positioning point. This segmentation of positioning functions ensures that alignment accuracy is maintained across the entire length, not just at one location.
Solution Approach 2:
The invention changes the positioning parameter from a single-point alignment to multi-point alignment along the length of the FPC. By forming positioning holes at multiple locations and using corresponding positioning pins, the alignment accuracy is improved across the entire manufacturing process.
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
Enables high-accuracy terminal formation and improved productivity by ensuring accurate alignment of the cover lay with the base material, reducing appearance defects and handling issues in long FPCs.
Implementation Method 1
an adhesive layer that adheres the protection layer to the base material
Data Source
AI summary
A wiring board include: a base material; a wiring disposed on the base material; and a cover lay laminated on the base material and that covers the wiring. The cover lay includes an open portion exposing a part of the wiring, the cover lay includes a protection layer and an adhesive layer that adheres the protection layer to the base material, the cover lay has burrs that do not contact the base material at an edge portion of the cover lay along the open portion, an end face of the adhesive layer that faces the open portion contacts the wiring, and an end portion of the adhesive layer that constitutes the burrs is outside the end face of the adhesive layer.