Composite Acoustic Membrane for Water-Resistant Transducers
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Solution Overview
Problem
Porous membranes used in electronic devices for water resistance are acoustically inferior due to the need for increased thickness, which compromises their ability to prevent water ingress while allowing air exchange and maintaining acoustic transparency.
Innovation Solution
A composite acoustic membrane with a nonporous region that is acoustically transparent and water-resistant, combined with a porous region that is air-permeable and water-impermeable, is used to inhibit water ingress, vent air, and transmit sound, while maintaining acoustic transparency and water resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a porous membrane is used to provide water resistance and air exchange, then water resistance is improved, but acoustic transparency deteriorates due to required increased thickness
Solution Approach 1:
The membrane is divided into distinct porous and nonporous regions, allowing each region to perform its specialized function. The porous regions provide water resistance and air exchange, while the nonporous regions maintain acoustic transparency without requiring increased overall thickness.
Solution Approach 2:
Different regions of the membrane have different structural properties - porous regions for water resistance and air exchange, nonporous regions for acoustic transparency. This local differentiation allows the membrane to achieve multiple functions simultaneously without compromising any single function.
2Reliability
If a nonporous barrier is used to prevent water ingress, then water resistance is improved, but gas exchange capability deteriorates
Solution Approach 1:
The barrier is segmented into porous and nonporous regions, where porous regions enable gas exchange while nonporous regions provide water resistance. This segmentation allows both functions to coexist in a single membrane structure.
Solution Approach 2:
The composite membrane structure serves multiple functions simultaneously - water resistance, air exchange, and acoustic transparency - within a single integrated component, eliminating the need for separate barriers for each function.
3Ease of operation
If a porous membrane is used to allow air exchange, then gas permeability is improved, but acoustic transparency deteriorates due to reactive resistance
Solution Approach 1:
The membrane is segmented into porous regions for air exchange and nonporous regions for acoustic transparency. The nonporous regions have low reactive resistance to acoustic waves, maintaining acoustic transparency while the porous regions handle air exchange independently.
Solution Approach 2:
Different regions have specialized properties: porous regions optimized for gas permeability and nonporous regions optimized for acoustic transparency. This local quality differentiation resolves the conflict between air exchange capability and acoustic transparency.
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 membrane effectively prevents water ingress, allows air exchange for pressure equalization, and maintains acoustic transparency, enhancing the performance of electronic devices in water-resistant applications.
Implementation Method 1
the nonporous region may be air impermeable and acoustically transparent to transmit sound
Implementation Method 2
the porous region may be air permeable (and water impermeable)
Implementation Method 3
the composite acoustic membrane may transmit sound toward the electroacoustic transducer
Implementation Method 4
allows venting of air from an electroacoustic transducer on another side of the membrane for barometric relief
Data Source
AI summary
An electronic device having a composite acoustic membrane to inhibit water ingress and to allow sound transmission, is disclosed. Embodiments include an electroacoustic transducer within an encased space of a casing, and a composite acoustic membrane between the electroacoustic transducer and an acoustic port in the casing. The acoustic membrane may include a nonporous region at least partly covering the acoustic port, and a porous region to vent the electroacoustic transducer volume to the encased space and/or to an environment surrounding the casing. Other embodiments are also described and claimed.