Earphone Microphone Assembly for Non-Occluding ANC Isolation
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Solution Overview
Problem
Existing earbuds with a leaky architecture face challenges in providing effective active noise cancellation (ANC) due to the lack of an airtight seal, which affects the microphone's ability to accurately distinguish between sound pressure inside the earbud and that received by the user's eardrum, leading to ineffective noise cancellation.
Innovation Solution
The earbud design incorporates a microphone assembly that fluidly isolates incoming sounds from outgoing sounds within the internal cavity, positioning the microphone closer to the acoustic port and using multiple layers to protect it from unwanted substances, ensuring accurate sound detection for ANC.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the microphone is positioned closer to the acoustic port in a leaky architecture earbud, then the ability to detect environmental sounds for ANC is improved, but the microphone becomes more exposed to contamination from unwanted substances
Solution Approach 1:
A microphone assembly is introduced as an intermediary structure between the acoustic port and the microphone. This assembly includes multiple protective layers (mesh, hydrophobic membrane, shim layers) that filter and protect the microphone while allowing sound to pass through, thus mediating between the need for sound detection and protection from contamination
Solution Approach 2:
The microphone assembly utilizes thin film structures including a hydrophobic membrane and mesh layers that are acoustically transparent but physically protective. These thin films allow sound waves to pass through while blocking contaminants, providing protection without compromising sound detection
2Object-affected harmful factors
If a microphone assembly with multiple protective layers is introduced, then the microphone is protected from contamination, but the device complexity increases
Solution Approach 1:
The protective structure is segmented into multiple functional layers: an outer mesh layer for physical filtration, a hydrophobic membrane layer for liquid repellency, and shim layers for structural support and sealing. This segmentation allows each layer to perform its specific function while collectively providing comprehensive protection
Solution Approach 2:
The microphone assembly serves multiple functions simultaneously: it acts as a protective barrier against contaminants, maintains acoustic transparency for sound detection, provides structural support for the microphone, and creates fluid isolation between incoming and outgoing sound paths. This multi-functionality reduces the need for separate components
3Measurement precision
If the microphone assembly defines a fluidly isolated acoustic path, then accurate detection of environmental sounds is enabled, but the manufacturing precision requirements increase
Solution Approach 1:
The microphone assembly acts as an intermediary structure that creates the fluidly isolated acoustic path. The assembly includes sealing elements and protective layers that mediate between the internal cavity and the external environment, ensuring acoustic isolation without requiring precision sealing throughout the entire earbud housing
Solution Approach 2:
Instead of requiring complete sealing of the entire earbud housing, the solution implements fluid isolation only at the critical microphone acoustic path. The microphone assembly provides localized sealing and protection, achieving the necessary acoustic isolation with less stringent overall manufacturing precision requirements
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 design enables effective ANC in earbuds with a leaky architecture by accurately detecting environmental sounds and protecting the microphone from contamination, enhancing noise cancellation performance.
Implementation Method 1
a port mesh disposed across the acoustic port forming a portion of an exterior surface of the earphone
Implementation Method 2
The microphone assembly may include a hydrophobic membrane spaced from the acoustic mesh
Implementation Method 3
The acoustic mesh may be positioned between the hydrophobic membrane and the port mesh
Data Source
AI summary
A non-occluding earphone including a device housing defining an internal cavity and including an ear-interface portion having an asymmetric shape, a port mesh disposed across the acoustic port forming a portion of an exterior surface of the earphone, an audio driver disposed within the internal cavity and aligned to emit sound through the acoustic port via a speaker acoustic path, a microphone disposed within the internal cavity, a microphone assembly coupled directly to the port mesh and disposed within the internal cavity at a location between the port mesh and the microphone, where the microphone assembly defines a microphone acoustic path from a point external to the earphone through the port mesh to the microphone that is fluidly isolated, within the internal cavity, from the speaker acoustic path up until the port mesh