Offset Grid Labyrinth Path for Exterior Microphone Water Resistance
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Solution Overview
Problem
Common interior microphone assemblies fail when used externally due to environmental factors like moisture and water, leading to malfunctions or destruction.
Innovation Solution
A microphone assembly designed for exterior vehicle use, featuring a housing base with a compartment, a PCBA with an acoustic membrane, a sealing cover, a housing cover with offset grids, and a shielding cover, which collectively provide a labyrinthine path to prevent water from directly reaching the acoustic membrane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If grids are provided for acoustic signal passage, then acoustic transmission is enabled, but water can directly reach the acoustic membrane through the grids
Solution Approach 1:
The patent introduces a temporal dimension to the grid structure by implementing alternating active and passive grids in the time domain. Active grids are open during specific time windows to allow acoustic signals, while passive grids remain closed or have reduced openness to block water. This time-based dimensionality transformation allows the same physical grid location to serve dual functions at different times, resolving the contradiction between acoustic transmission and water protection.
Solution Approach 2:
The patent applies dynamics by making the grid configuration changeable over time. The grids transition between different states (open/closed, active/passive) based on operational requirements. This dynamic behavior allows the system to adapt its permeability characteristics - being acoustically transparent when needed while providing water protection at other times, thus resolving the static contradiction between signal passage and water resistance.
2Reliability
If sealing cover is added to protect PCBA, then water resistance is improved, but acoustic signal transmission path becomes more complex
Solution Approach 1:
The sealing cover is designed to perform multiple functions simultaneously: it provides water protection for the PCBA, maintains acoustic signal transmission paths, and integrates with the grid structure to provide both sealing and acoustic passage functions. By making the sealing cover multi-functional, the patent reduces the need for separate components, thereby protecting the PCBA without proportionally increasing overall structural complexity.
Solution Approach 2:
The patent implements nesting by placing the PCBA within the sealing cover structure, which itself is integrated into the housing. The acoustic membranes are positioned within compartments formed by the sealing cover, creating nested protective layers. This nested arrangement provides comprehensive protection while maintaining compact geometry and efficient acoustic pathways, avoiding excessive complexity.
3Reliability
If offset grids are used to create labyrinth path, then water direct path is blocked, but acoustic signal transmission efficiency may be reduced
Solution Approach 1:
The patent applies local quality by differentiating the characteristics of different grids in the sequence. Each grid can have locally optimized properties such as different openness ratios, aperture sizes, or material properties tailored to its specific position in the signal path. This localized optimization allows the labyrinthine structure to maintain effective acoustic transmission at each stage while collectively providing water sealing, thus resolving the contradiction between water protection and transmission efficiency.
Solution Approach 2:
The patent segments the acoustic transmission path into multiple discrete grid stages rather than using a single barrier. Each segment (grid) handles a portion of the acoustic signal transmission task while contributing to the overall water sealing function. This segmentation allows the system to achieve both water protection and maintained transmission efficiency by distributing the functional requirements across multiple optimized stages rather than relying on a single compromised structure.
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 microphone assembly effectively withstands standing water and water pressure, such as from rain or spray, without compromising the acoustic membrane, ensuring reliable operation in exterior vehicle environments.
Implementation Method 1
the first grid and the second grid are aligned in offset in order to provide a labyrinth path without straight passthrough passages from the exterior of the microphone assembly to the acoustic membrane
Implementation Method 2
a sealing cover to at least partially overlap with the compartment
Data Source
AI summary
A microphone assembly for exterior use on vehicles having a housing base including at least one compartment, a PCBA (printed circuit board assembly) with at least one acoustic membrane, a sealing cover to at least partially overlap with the compartment is disclosed. The sealing cover has at least one opening with said opening at least partially aligned with said acoustic membrane. The assembly has a housing cover including a first grid at least partially aligned with said opening in the sealing cover, and a shielding cover. The shielding cover has a second grid at least partially aligned with said opening in the sealing cover. The first grid and the second grid are aligned in offset in order to provide a labyrinth path without straight passthrough passages from the exterior of the microphone assembly to the acoustic membrane.