Waterproof Member with Shielded Porous Layer for Vapor Barrier
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Solution Overview
Problem
The sound-transmitting membranes used in waterproof sound-transmitting members have in-plane air permeability, allowing water vapor to enter electronic device housings and causing condensation, which can lead to malfunction and complicates air tightness testing.
Innovation Solution
A waterproof member with a frame-shaped first and second adhesive layer and a porous layer in between, where the porous layer's outer boundary is shielded by the adhesive layers, preventing omnidirectional air permeability and cohesive failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a porous sound-transmitting membrane is used to cover the housing opening, then sound transmission is enabled while preventing foreign matters from entering, but in-plane air permeability allows water vapor to flow into the housing causing condensation and malfunction
Solution Approach 1:
The adhesive layer is divided into a porous region (aligned with the sound-transmitting membrane) and a non-porous region (peripheral portion). This segmentation allows the porous region to transmit sound while the non-porous peripheral region blocks water vapor infiltration, resolving the contradiction between sound transmission and vapor prevention.
Solution Approach 2:
Different regions of the adhesive layer are assigned different properties: the central porous region allows air and sound passage, while the peripheral non-porous region provides water vapor barrier function. This local differentiation of properties enables simultaneous achievement of sound transmission and vapor blocking.
2Strength
If the entire peripheral portion of the support layer extends outwardly beyond the adhesive layer, then structural support is enhanced, but the support layer's porous structure allows water vapor to enter through its peripheral surface
Solution Approach 1:
The adhesive layer is segmented into porous and non-porous regions, with the non-porous peripheral portion extending beyond the porous support layer. This ensures the support layer's structural function while the overlapping non-porous adhesive region blocks water vapor access to the support layer's porous peripheral surface.
Solution Approach 2:
The non-porous peripheral adhesive layer acts as an intermediary barrier between the external environment and the porous support layer's peripheral surface. It prevents water vapor from reaching the support layer's porous structure while allowing the support layer to maintain its structural support function.
3Reliability
If a sound-transmitting membrane with three-dimensional porous structure is used, then sound transmission and through-thickness air permeability are achieved, but in-plane air permeability complicates air tightness testing and allows vapor flow
Solution Approach 1:
The adhesive layer is segmented into porous and non-porous regions. The non-porous peripheral region creates a sealed boundary that prevents in-plane air flow through the porous membrane's edges, enabling accurate air tightness testing while preserving the membrane's sound transmission capability through the porous central region.
Solution Approach 2:
The adhesive layer provides different functional qualities in different regions: the porous central region maintains sound transmission, while the non-porous peripheral region provides air sealing for accurate tightness testing. This local quality differentiation resolves the contradiction between sound transmission and measurement precision.
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
This configuration prevents water vapor from entering the electronic device, reduces the risk of malfunction, and allows for accurate air tightness testing by ensuring the adhesive layers are bonded directly, preventing cohesive failure during removal.
Implementation Method 1
The sound-transmitting membranes used in the waterproof sound-transmitting members of Patent Literature 2 and Patent Literature 3 each have a three-dimensional porous structure. Therefore, these sound-transmitting membranes have not only through-thickness air permeability but also in-plane air permeability.
Implementation Method 2
a first adhesive layer having a frame shape; a second adhesive layer having a frame shape... the first adhesive layer is bonded directly to the second adhesive layer in a region outside the outer boundary of the porous layer
Data Source
Figure 1~2
Figure 3~5
Figure 6
AI summary
A waterproof member (20) includes a first adhesive layer (22), a second adhesive layer (24), and a porous layer (26). The porous layer (26) is disposed between the first adhesive layer (22) and the second adhesive layer (24). The first adhesive layer (22) and the second adhesive layer (24) each have a frame shape in plan view. When the first adhesive layer (22), the second adhesive layer (24), and the porous layer (26) are seen in plan view, the outer boundary of the porous layer (26) lies within the outer boundary of the first adhesive layer (22) and the outer boundary of the second adhesive layer (24). The first adhesive layer (22) is bonded directly to the second adhesive layer (24) in a region outside the outer boundary of the porous layer (26). The porous layer (26) has a peripheral surface that is shielded from outside by the first adhesive layer (22) and the second adhesive layer (24).