Rigid-Flex PCB Size Matching via C-Shaped Cutouts
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Solution Overview
Problem
The production of rigid-flex printed circuit boards (RFPCBs) often results in wastage of materials due to mismatched standard lengths and widths of flexible and rigid printed circuit boards, leading to increased costs.
Innovation Solution
A method involving the creation of C-shaped cutouts and protrusions on flexible printed circuit boards (FPCBs) to enable precise alignment and combination with rigid printed circuit boards (RPCBs), followed by reinforcement layers and via formation to achieve size matching and reduced material waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If standard length and width FPCBs and RPCBs are used, then manufacturing is simplified, but material wastage increases due to size mismatch
Solution Approach 1:
The FPCB is divided into a rigid portion and a flexible portion with different standard sizes. The rigid portion uses a standard-sized raw board for easy manufacturing, while the flexible portion can be custom-cut to match the RPCB size, thereby reducing material wastage while maintaining manufacturing simplicity.
Solution Approach 2:
Different portions of the FPCB are designed with different characteristics: the rigid portion has standard dimensions for ease of manufacturing, while the flexible portion has customized dimensions to match the RPCB size, minimizing material wastage locally where needed.
2Loss of substance
If FPCBs are custom-cut to match RPCB sizes, then material wastage is reduced, but manufacturing complexity increases
Solution Approach 1:
By segmenting the FPCB into rigid and flexible portions with different size requirements, the patent allows the rigid portion to be manufactured using standard processes while the flexible portion can be custom-cut, reducing overall manufacturing complexity compared to custom-cutting the entire FPCB.
Solution Approach 2:
The rigid portion is pre-manufactured with standard dimensions before the flexible portion is custom-cut to match the RPCB size. This preliminary action simplifies the overall manufacturing process by establishing a standardized base structure before performing custom modifications.
3Manufacturing precision
If C-shaped cutouts and protrusions are added to FPCBs, then alignment precision is improved, but structural complexity increases
Solution Approach 1:
C-shaped cutouts and protrusions are added to specific asymmetric locations on the FPCB to achieve precise alignment with the RPCB. These asymmetric features are strategically placed only where needed for alignment, minimizing the increase in structural complexity while improving alignment precision.
Solution Approach 2:
The C-shaped cutouts and protrusions act as intermediary alignment features between the FPCB and RPCB. These intermediate structural elements facilitate precise positioning and alignment during assembly, reducing the need for more complex alignment mechanisms.
Data Source
AI summary
An RFPCB includes a reinforcement layer and at least two FPCBs spliced together to match the reinforcement layer in shape and size. The FPCBs are adhered onto the reinforcement layer. The reinforcement layer includes circuits connected with the FPCB and has portions removed to obtain a desired flexibility.