Multi-layer FPCB with Segmented Layers for Flexibility
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Solution Overview
Problem
Conventional multi-layer Flexible Printed Circuit Boards (FPCBs) suffer from low flexibility due to increased thickness, leading to reduced engagement strength between connectors and potential damage or cracking, which degrades product reliability.
Innovation Solution
The design alternates circuit patterns, adhesive layers, and insulating/protecting layers on the top and bottom surfaces of a base layer, with these components removed from specific regions to reduce thickness, enhance flexibility, and improve connector engagement strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multi-layer FPCB is used to accommodate more components, then component density increases, but thickness increases and flexibility decreases
Solution Approach 1:
The FPCB is divided into multiple layers with circuit patterns, adhesive layers, and insulating/protecting layers arranged alternately on top and bottom surfaces. Specific layers are selectively removed from certain regions to create a segmented structure that reduces thickness while maintaining component density in remaining areas.
Solution Approach 2:
The patent transitions from a conventional single-sided layer arrangement to a multi-layer alternating structure on both top and bottom surfaces of the base layer. This dimensional reorganization allows components to be distributed across multiple levels, increasing effective component density without proportionally increasing overall thickness.
2Ease of operation
If thickness of FPCB is reduced to improve flexibility, then flexibility improves, but connector engagement strength may be compromised
Solution Approach 1:
Different regions of the FPCB have different structural characteristics. Regions with connectors maintain complete multi-layer structures for strength, while other regions have selectively removed layers to reduce thickness and improve flexibility. This local differentiation allows simultaneous optimization of both flexibility and connector engagement strength.
Solution Approach 2:
The FPCB structure is segmented into regions with different layer configurations. By removing specific layers (circuit patterns, adhesive layers, insulating/protecting layers) from non-connector regions while preserving them in connector regions, the patent creates zones with optimized properties for their specific functions.
3Reliability
If conventional multi-layer structure is used, then durability is maintained, but damage and cracking occur in circuit-side connector after prolonged use
Solution Approach 1:
Specific layers (circuit patterns, adhesive layers, insulating/protecting layers) are extracted or removed from regions adjacent to circuit-side connectors. This extraction eliminates the source of stress concentration and cracking that occurs in conventional multi-layer structures during prolonged flexing, thereby preventing damage while maintaining durability in remaining structures.
Data Source
AI summary
A multi-layer Flexible Printed Circuit Board (FPCB) for an electronic device, in which a plurality of components are provided alternately on a top surface and a bottom surface of a base layer and the components are removed from the other region. The multi-layer FPCB includes a base layer, a first circuit pattern provided on a side region on a top surface of the base layer, a first adhesive layer provided in the first circuit pattern, a second circuit pattern provided on a bottom surface of the base layer and in an other-side region opposite to the side region, a second adhesive layer provided in the second circuit pattern, a first insulating/protecting layer provided on a top surface of the first adhesive layer, and a second insulating/protecting layer provided on a bottom surface of the second adhesive layer.