Earmate Magnetic Shielding for Particle Ingress Mitigation
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Solution Overview
Problem
As electronic devices become thinner, the magnetic fields from voice coil motors can attract small magnetically permeable particles, leading to their ingress through openings, which can accumulate and degrade or prevent the operation of audio components.
Innovation Solution
Incorporating magnetically permeable materials around the openings and within the speaker enclosure to redirect the magnetic field, preventing the ingress of magnetically attractable particles while maintaining an open pathway for audio signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a protective screen is positioned across the opening to block particles, then particle ingress is prevented, but audio signal passage is substantially degraded
Solution Approach 1:
A mesh screen with aperture size between 10-100 microns is introduced as an intermediary element across the opening. This mesh screen selectively blocks magnetically attractable particles while allowing audio signals to pass through, resolving the contradiction between particle protection and audio signal transmission that arises when using solid protective screens.
Solution Approach 2:
The protective screen uses localized aperture sizing (10-100 microns) that is specifically optimized for the dual function of blocking particles while transmitting audio frequencies. This local quality adjustment allows the screen to perform differently for particles versus audio signals, enabling both protection and signal passage.
2Power
If the magnetic field is strengthened to improve audio signal generation, then audio output is enhanced, but particle attraction and ingress increase
Solution Approach 1:
The magnetic field, which causes harmful particle attraction, is redirected through magnetically permeable material to converge on a collection aperture. This converts the harmful particle attraction effect into a beneficial particle collection mechanism, allowing strong magnetic fields for audio generation while preventing particle ingress into the device interior.
Solution Approach 2:
Magnetically permeable material is introduced as an intermediary between the magnetic field source and the device interior. This material redirects and contains the magnetic field lines, confining them to specific pathways that lead to particle collection apertures rather than allowing random particle attraction across all openings.
3Object-affected harmful factors
If magnetically permeable material is added to redirect magnetic fields, then particle ingress is reduced, but device complexity increases
Solution Approach 1:
The speaker enclosure is merged with magnetically permeable material properties, combining the structural housing function with the magnetic field redirection function into a single integrated component. This reduces device complexity by eliminating separate shielding elements and using the enclosure itself to perform dual functions.
Solution Approach 2:
The speaker enclosure is designed to serve multiple functions: providing structural housing, directing acoustic signals, and redirecting magnetic fields for particle collection. This multi-functionality reduces the need for additional components, thereby minimizing device complexity while achieving particle ingress prevention.
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
Reduces the accumulation of magnetically attractable particles on the diaphragm, preventing degradation and ensuring the continued operation of audio components by minimizing the magnetic field's concentration near the opening, thus enhancing the structural integrity and audio performance of the device.
Implementation Method 1
a magnetic element that emits a magnetic field used to actuate an acoustic membrane
Implementation Method 2
magnetically permeable material positioned proximate the opening in a manner that shapes the magnetic field
Implementation Method 3
The electrically conductive ring and the magnet cooperate to vibrate the electrically conductive ring so that the diaphragm generates an audio signal
Data Source
AI summary
This document describes methods and apparatus for reducing a magnetic field emitted by an earpiece assembly from extending substantially outside a device associated with the earpiece assembly. Where the earpiece assembly is susceptible to ingress of magnetically attractable particles into the earpiece assembly such a reduction can prolong an operational life of the earpiece assembly. By insert molding magnetically permeable materials throughout an enclosure that surrounds and supports a permanent magnet of the earpiece assembly, a portion of a magnetic field emanating from the permanent magnet that extends outside the device can be substantially reduced or redirected so that the magnetic field ceases to draw the magnetically attractable particles into the earpiece assembly.