Composite Filtering Construction for Microphones
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Solution Overview
Problem
Existing filtering solutions for acoustic and electronic applications fail to provide both effective sound transmission and protection against liquids and smaller particles with low acoustic impedance, limited durability, and ease of handling and processing.
Innovation Solution
A composite filtering construction combining a precision synthetic monofilament fabric with a nanoporous membrane, laminated together using methods like reactive polyurethane or ultrasound, to create a single medium with high air permeability and structural strength, allowing for selective filtering and resistance to liquid penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a fabric material is used for sound transmission by passing air, then acoustic characteristics are improved, but protection against water and liquids is insufficient
Solution Approach 1:
The patent applies composite materials by combining a fabric layer with a microporous membrane layer to create a composite filtering construction. The fabric provides acoustic characteristics for sound transmission, while the microporous membrane provides protection against water and liquids. This composite structure resolves the contradiction by integrating the beneficial properties of both materials.
Solution Approach 2:
The patent merges the fabric material and microporous membrane into a single integrated filtering construction. The fabric and membrane are combined such that they work together to provide both acoustic transmission and liquid protection, eliminating the need for separate components and achieving dual functionality.
2Object-affected harmful factors
If a membrane is used for protection against water and liquids, then protective properties are improved, but sound transmission capability is reduced
Solution Approach 1:
The patent uses composite materials where a microporous membrane is combined with a fabric layer. The microporous membrane provides liquid protection while its porous structure allows sound transmission. The fabric layer complements this by providing additional acoustic characteristics, ensuring that sound transmission is not compromised while maintaining liquid protection.
Solution Approach 2:
The patent applies local quality by having different layers perform different functions: the microporous membrane layer provides liquid protection with controlled porosity for sound transmission, while the fabric layer provides acoustic characteristics. Each layer is optimized for its specific function, and together they resolve the contradiction between protection and sound transmission.
3Manufacturing precision
If fabric mesh openings are reduced to protect against smaller particles, then filtering precision is improved, but acoustic impedance increases
Solution Approach 1:
The patent applies composite materials where the fabric layer with reduced mesh openings provides filtering precision for smaller particles, while the microporous membrane layer maintains low acoustic impedance. The combination allows the fabric to be optimized for particle filtration without compromising acoustic performance, as the membrane compensates for the increased impedance.
Solution Approach 2:
The microporous membrane acts as an intermediary between the fabric layer and the external environment. It allows sound waves to pass through with low impedance while the fabric layer provides the fine particle filtration. The membrane mediates the acoustic transmission, preventing the fabric's fine mesh from creating high acoustic impedance.
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 composite construction achieves high filtering precision, selectivity, and resistance to liquids while maintaining low acoustic impedance, ensuring long operating life and ease of handling, with improved sound transmission and protection against smaller particles.
Implementation Method 1
a nanoporous membrane, laminated together using methods like reactive polyurethane or ultrasound, to create a single medium with high air permeability and structural strength, allowing for selective filtering and resistance to liquid penetration
Implementation Method 2
sound is transmitted either by air passing through a porous surface
Implementation Method 3
sound is transmitted either by air passing through a porous surface, or by vibrations of a very thin material, such as a film or a membrane
Implementation Method 4
laminated together using methods like reactive polyurethane or ultrasound
Data Source
AI summary
A composite multilayer filtering construction for use in filtering applications requiring a high filtering efficiency for particles of the order of microns and a high permeability of the filtering medium, and for use as a sub-component within acoustic and electronic products, in particular microphones and speakers, comprises at least a first layer of polymeric nanoporous membrane and at least a second layer of a synthetic monofilament precision fabric, the first polymeric nanoporous membrane layer being coupled to the second precision fabric layer thereby providing an integral filtering medium adapted to prevent a passage therethrough of particles even of 1-2 μm and of pressurized liquids.