Flexible Printed Circuit Board Reinforcement for Waterproof Sealing
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Solution Overview
Problem
Flexible printed circuit boards (FPCBs) in electronic devices face issues with waterproofing due to their rigidity, which can lead to deformation under external forces, causing gaps and allowing water to enter the waterproof area, and inter-layer peel-off in multi-layer configurations, compromising the waterproofness of the device.
Innovation Solution
Incorporating a reinforced portion of the FPCB with a larger width than other parts, which acts as a cantilever to reduce deformation, and using a bonding member between layers to enhance rigidity and prevent inter-layer peel-off, thereby improving the waterproofing of the electronic device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flexible printed circuit board is used to pass through a through hole in the housing, then electrical connection between waterproof and non-waterproof areas is enabled, but the rigidity of the FPCB causes the waterproofing member to deform under external force, creating gaps that allow water ingress
Solution Approach 1:
The FPCB is designed with different width sections: a first width portion that is wider and provides rigidity support for the waterproofing member, and a second width portion that is narrower and allows flexibility. This local quality differentiation enables the waterproofing member to maintain its shape and sealing function while the FPCB retains its flexibility for electrical connection.
2Adaptability or versatility
If the FPCB is implemented with several overlapping sheets or multiple conductive layers, then electrical functionality is enhanced, but the insertion portion bends causing inter-layer peel-off and creating gaps for water entry
Solution Approach 1:
The FPCB structure includes a reinforced portion with multiple layers bonded together using a bonding member. This localized multi-layer construction provides enhanced electrical functionality and structural stability at the critical insertion portion, while preventing inter-layer peel-off that would create gaps for water ingress.
3Reliability
If the waterproofing member is made elastic to seal the gap, then waterproofing is improved, but the FPCB rigidity causes deformation of the waterproofing member under external force
Solution Approach 1:
The FPCB has a wider first width portion that acts as a rigid support structure for the waterproofing member, preventing deformation under external force. The waterproofing member can remain elastic for sealing while the wider FPCB portion maintains its shape, ensuring the gap remains sealed.
Data Source
AI summary
An electronic device is provided. The electronic device includes a first housing including a first through hole, a flexible printed circuit board including a plurality of layers, a first portion of the flexible printed circuit board disposed to pass through the through hole, a bonding member being disposed between the plurality of layers constituting the first portion, and a waterproofing member formed to surround at least part of the first portion of the flexible printed circuit board.