Implantable Microphone With Divided Volumes for Middle Ear

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Solution Overview

Problem

Implantable microphones for cochlear implants face challenges such as loss of directional sound filtering, adverse tissue reactions, high power consumption, bone erosion, and biocompatibility issues due to existing conversion methods, particularly with piezoelectric materials.

Innovation Solution

An implantable microphone design featuring a housing with divided volumes, a first membrane coupled to an auditory ossicle, and a second membrane with a vibration sensor that converts movement into electrical signals, using piezoelectric or MEMS differential capacitors, with fluid flow through openings to mitigate static membrane deflections and enhance sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If piezoelectric materials are used for sound conversion, then power consumption is reduced, but biocompatibility problems occur due to interactions with body fluids

Engineering Contradiction:

Improvepower consumptionVSAvoidbiocompatibility

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

A hermetic barrier (membrane) is introduced as an intermediary between the piezoelectric material and body fluids. This barrier allows mechanical vibrations to pass through while preventing direct contact between fluids and piezoelectric material, thus maintaining both low power consumption and biocompatibility

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

A thin hermetic membrane is used to encapsulate the piezoelectric material. This flexible film transmits acoustic vibrations effectively while providing a permanent seal against body fluids, resolving the contradiction between energy efficiency and biocompatibility

Inventive Principle:

Principle #30Flexible shells and thin films

2Productivity

If the converter is firmly attached to ear ossicles, then conversion efficiency is improved, but bone erosion occurs

Engineering Contradiction:

Improveconversion efficiencyVSAvoidbone erosion

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

A membrane is introduced as a mediator between the converter and ear ossicles. This membrane transmits vibrations effectively for good conversion efficiency while distributing mechanical stress to prevent bone erosion, eliminating the need for firm attachment

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

A flexible membrane couples the converter to the ossicles, providing sufficient mechanical coupling for efficient vibration transfer while being gentle enough to avoid tissue damage and bone erosion

Inventive Principle:

Principle #30Flexible shells and thin films

3Reliability

If electromagnetic converters are used, then sound conversion is achieved, but power consumption is high

Engineering Contradiction:

Improvesound conversion capabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent replaces electromagnetic conversion (which requires high power) with direct piezoelectric conversion. The piezoelectric material directly converts mechanical vibrations from the ossicles into electrical signals, eliminating the need for high-power electromagnetic fields while maintaining sound conversion capability

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 configuration reduces mechanical stress on the vibration sensor, improves sensitivity, and minimizes tissue trauma, while maintaining biocompatibility and stability, optimizing the microphone's placement and performance within the middle ear.

Implementation Method 1

a vibration sensor coupled to the second membrane and configured to measure the movement of the second membrane and to convert the measurement into an electrical signal

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

a vibration sensor coupled to the second membrane and configured to measure the movement of the second membrane and to convert the measurement into an electrical signal

Methodology Applied

Scientific EffectCapacitive effect: Capacitance

Data Source

PatentUS9794702B2Implantable microphone for hearing systems

Publication Date: 2017.10.17 MED EL ELEKTROMEDIZINISCHE GERAETE GMBH

AI summary

An implantable microphone for use in hearing systems includes a housing having a sidewall, a first membrane coupled to a top portion of the housing and configured to move in response to movement from an auditory ossicle, and a second membrane coupled to the sidewall such that an interior volume of the housing is divided into a first volume and a second volume. The first volume has an opening that permits fluid to flow out from the first volume. The implantable microphone also includes a vibration sensor coupled to the second membrane and configured to measure the movement of the second membrane and to convert the measurement into an electrical signal. The vibration sensor may include a piezoelectric sensor and/or a MEMS sensor.