PTFE Membrane Pore Control for Waterproof Sound Transmission
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Solution Overview
Problem
There is a challenge in enhancing the waterproofness of sound-permeable membranes without compromising sound permeability, as imperforate membranes provide good waterproofness but poor sound permeability.
Innovation Solution
A waterproof sound-permeable membrane using a polytetrafluoroethylene (PTFE) membrane with an average pore diameter of 0.02 µm to 0.1 µm and porosity of 5% to 25%, which balances waterproofness and sound permeability, featuring a solid structure with pores extending through the thickness, allowing for effective sound transmission while preventing water entry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an imperforate membrane is used as a waterproof sound-permeable membrane, then waterproofness is improved, but sound permeability deteriorates
Solution Approach 1:
The patent applies porous materials by using a polytetrafluoroethylene membrane with controlled pore structures (average pore diameter of 0.03 μm to 0.1 μm and porosity of 10% to 30%). This porous structure allows sound waves to pass through while the small pore size prevents water penetration, thereby resolving the contradiction between waterproofness and sound permeability
Solution Approach 2:
The patent employs parameter changes by precisely controlling the membrane's physical parameters - specifically setting the average pore diameter between 0.03 μm and 0.1 μm and porosity between 10% and 30%. These parameter optimizations enable the membrane to block water while maintaining sound transmission, thus resolving the technical contradiction
2Reliability
If the pore diameter is reduced to enhance waterproofness, then waterproofness is improved, but sound permeability deteriorates
Solution Approach 1:
The patent optimizes the pore diameter parameter within a specific range (0.03 μm to 0.1 μm) to achieve the desired balance. This parameter control ensures that pores are small enough to prevent water entry while remaining large enough to allow sound transmission, resolving the contradiction between waterproofness and sound permeability
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
The membrane achieves enhanced waterproofness with minimal loss in sound permeability, as demonstrated by water entry pressure and insertion loss measurements, ensuring both properties are well-balanced for electronic devices.
Implementation Method 1
The polytetrafluoroethylene membrane has an average pore diameter of 0.02 μm or more and 0.1 μm or less as measured according to ASTM F316-86 and has a porosity of 5% or more and 25% or less
Data Source
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AI summary
Provides is a waterproof sound-permeable membrane (10) adapted to permit passage of sound and prevent entry of water. The waterproof sound-permeable membrane (10) includes a sound-permeation region (11) having a polytetrafluoroethylene (PTFE) membrane (20). The polytetrafluoroethylene membrane (20) has an average pore diameter of 0.02 µm or more and 0.1 µm or less as measured according to ASTM F316-86 and has a porosity of 5% or more and 25% or less. The waterproof sound-permeable membrane (10) is suitable for application to an electronic device containing an acoustic device.