Passive Vibration Cancellation for Microphone Assemblies

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Solution Overview

Problem

Microphones in auditory prostheses are fragile and prone to damage from external elements like water, dust, and vibrations, which can lead to permanent degradation and render the device ineffective.

Innovation Solution

A passive vibration cancellation system using multiple flexible diaphragms and a rigid support structure that deforms differently to sound and vibrations, combined with a waterproof enclosure, to reduce vibration transmission and protect the microphone from external substances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a waterproof membrane is used to cover the microphone, then waterproofing is improved, but vibrational noise increases

Engineering Contradiction:

ImprovewaterproofingVSAvoidvibrational noise

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The waterproof cover is divided into multiple diaphragms (first diaphragm, second diaphragm, third diaphragm) that can deform independently. This segmentation allows each diaphragm to respond differently to vibrations, enabling vibration cancellation while maintaining waterproofing. The multiple diaphragms work together to filter out vibrational noise before it reaches the microphone.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The second diaphragm acts as an intermediary element between the first and third diaphragms. It deforms in the same direction as the first diaphragm during vibrations, creating a canceling effect that reduces vibrational noise transmission to the microphone while still allowing acoustic signals to pass through.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If a semi-water permeable filter is used, then substance ingress resistance is improved, but protection against vigorous aquatic activities is insufficient

Engineering Contradiction:

Improvesubstance ingress resistanceVSAvoidprotection against extreme conditions

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The invention uses multiple flexible diaphragms made of waterproof materials to create a sealed enclosure around the microphone. These flexible membranes can deform to accommodate vibrations and pressure changes while maintaining complete waterproofing, providing protection against vigorous aquatic activities that a semi-permeable filter cannot withstand.

Inventive Principle:

Principle #30Flexible shells and thin films

3Reliability

If the microphone is made more robust to withstand extreme conditions, then reliability in extreme environments is improved, but acoustic sensitivity may deteriorate

Engineering Contradiction:

Improvewithstand extreme conditionsVSAvoidacoustic sensitivity

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

By segmenting the waterproof cover into multiple diaphragms, the system achieves robust protection against extreme conditions while maintaining acoustic sensitivity. Each diaphragm can be optimized for its specific function: the first diaphragm provides external protection, the second diaphragm cancels vibrations, and the third diaphragm allows acoustic signals to reach the microphone with minimal distortion.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The second diaphragm serves as a mediator that blocks harmful vibrations from reaching the microphone while allowing acoustic signals to pass through. This intermediary structure enables the microphone to remain sensitive to sound while being protected from extreme environmental conditions.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 system effectively cancels vibrations and maintains acoustic sensitivity while providing waterproof protection, reducing vibration-induced noise and preventing damage from external elements, resulting in a more reliable auditory prosthesis.

Implementation Method 1

The assembly includes multiple flexible diaphragms that deform in opposite directions when acted upon by sound

Methodology Applied

Scientific EffectSound wave propagation: Sound

Implementation Method 2

The passive vibration cancellation system reduces vibration transmission between the housing and the microphone

Methodology Applied

Scientific EffectVibration cancellation: Vibration

Implementation Method 3

An assembly manufactured of a plurality of waterproof diaphragms and a more rigid support structure is sized to cover the sound-receiving component

Methodology Applied

Scientific EffectWaterproofing: Physical Containment

Implementation Method 4

The assembly can include a collar or other compliant element to help secure the assembly into the auditory prosthesis housing, while further reducing vibration transmission

Methodology Applied

Scientific EffectVibration isolation: Damping

Data Source

PatentUS10306385B2Passive vibration cancellation system for microphone assembly

Publication Date: 2019.05.28 COCHLEAR LIMITED

AI summary

A passive vibration cancellation system manufactured of a plurality of waterproof diaphragms and a more rigid support structure is sized to cover a microphone of an auditory prosthesis. The system includes multiple flexible diaphragms that deform in opposite directions when acted upon by sound, but deform in the same direction when acted upon by vibrations. The system can further include a collar or other compliant element to help secure a microphone assembly into the auditory prosthesis housing, while further reducing vibration transmission between the housing and the microphone.