Electronic Device Waterproofing via FPC Sealant Injection
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Solution Overview
Problem
Existing electronic devices, such as portable terminals, face challenges in achieving effective waterproofing, particularly in ensuring watertight separation between regions while allowing communication through specific gaps, which complicates the assembly process and requires precise sealing to maintain different levels of waterproofness.
Innovation Solution
The electronic device incorporates an extending member, like a flexible printed circuit (FPC), connected to two regions with a sealing region formed by a gap, where a sealant is injected through a through hole to separate these regions watertightly, allowing for varying levels of waterproofness and simplifying the assembly by preventing unwanted sealant placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a waterproof structure is implemented to separate regions, then waterproofness is improved, but device complexity increases due to the need for precise sealing and multiple components
Solution Approach 1:
The waterproof structure is segmented into distinct functional components: a waterproof adhesive layer on the case, a sealing member with specific geometric features (first surface, second surface, third surface), and a through-hole for controlled adhesive application. This segmentation allows each component to perform its specific function independently, simplifying the overall assembly process while maintaining effective waterproofing between the first region and second region.
Solution Approach 2:
The waterproof adhesive is pre-applied to the case in a controlled manner through the through-hole before final assembly. The sealing member is designed with pre-formed geometric features that guide the adhesive placement. This preliminary action ensures proper sealing without requiring complex real-time adjustment during assembly, thereby improving waterproofness while managing device complexity.
2Reliability
If precise sealing is required to maintain different waterproofness levels, then waterproofness is improved, but manufacturing precision requirements increase
Solution Approach 1:
A waterproof adhesive layer serves as an intermediary substance between the case and the sealing member. This adhesive mediator fills and seals the gap between the first surface of the extending member and the case, creating a reliable waterproof barrier without requiring extremely tight mechanical tolerances. The adhesive compensates for minor dimensional variations, maintaining waterproofness while reducing manufacturing precision requirements.
Solution Approach 2:
The sealing member incorporates a flexible waterproof adhesive layer that can conform to slight variations in the mating surfaces. This flexible film approach allows the sealing structure to accommodate normal manufacturing tolerances while still achieving effective waterproofing, thereby maintaining reliability without demanding excessive manufacturing precision.
3Ease of manufacture
If sealant is injected through a through hole to separate regions, then ease of manufacture is improved, but risk of undesired sealant placement increases
Solution Approach 1:
The through-hole is strategically positioned at a specific location on the case where sealant injection will not compromise the waterproof integrity. The local geometry around the through-hole is designed to guide the sealant flow into the intended gap between the extending member and the case. This localized design ensures easy manufacture through simple injection while preventing undesired sealant placement that would compromise reliability.
4Reliability
If multiple members are used to form sealing region, then waterproofness is improved, but device complexity increases
Solution Approach 1:
The sealing function is merged into a single integrated sealing member that includes the first surface, second surface, and third surface as unified geometric features. This sealing member works in combination with the case (including the through-hole) and the extending member to form the complete sealing region. By merging the sealing functionality into one component rather than using multiple separate sealing elements, the design achieves improved waterproofness while minimizing the increase in device complexity.
Data Source
AI summary
An electronic device includes an FPC as an extending member which extends to connect a first region and a second region to each other and includes a first surface and a second surface facing away from each other, a first member located to abut on the first surface, and a second member located to abut on the second surface. The first member and the second member form in combination, a sealing region which surrounds a certain section of the extending member with a gap being located in part. The first region and the second region are watertightly separated from each other by a sealant located in the gap at least in the sealing region. The first member includes a through hole which allows communication between the gap and the outside.