Hearing Device Valve for Acoustic Impedance Control

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Solution Overview

Problem

Hearing aids and similar devices face challenges in controlling sound transmission, as vents allow sound to pass in both directions, leading to unwanted noise leakage and impedance changes in the ear canal, which affect acoustic filtering.

Innovation Solution

A personal hearing device with a valve system that can switch between open and closed positions to control sound frequencies between 700-2000Hz, using an actuator to drive the closing element and position it outside the sound channel, creating a low-pass filter with a roll-off frequency of at least 500Hz to allow voice frequencies to reach the eardrum while blocking higher frequencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a vent is provided in the hearing device to allow sound passage, then sound transmission is improved, but sound leakage and impedance changes occur

Engineering Contradiction:
Improvesound transmissionVSAvoidsound leakage
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent applies a dynamic valve mechanism that can switch between open and closed states based on operational requirements. The valve is actuated by a motor driver to open during voice calls to allow natural sound transmission and to close during music playback to prevent sound leakage and maintain acoustic impedance. This dynamic switching resolves the contradiction by adapting the vent state to different usage scenarios.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the acoustic parameters of the hearing device by controlling the valve position. When the valve is open, the acoustic impedance and sound transmission characteristics are optimized for voice calls. When the valve is closed, the acoustic impedance is maintained and sound leakage is prevented for music playback. This parameter change approach allows the device to resolve the contradiction between sound transmission and sound leakage prevention.

Inventive Principle:
Principle #35Parameter changes

2Object-generated harmful factors

If the valve closes the sound channel to block sound, then sound leakage is reduced, but sound transmission is blocked

Engineering Contradiction:
Improvesound leakageVSAvoidsound transmission
Core Design Contradiction:
Object-generated harmful factorsVSEase of operation

Solution Approach 1:

The dynamic valve mechanism switches between closed and open states based on the audio source. During music playback, the valve closes to prevent sound leakage and maintain acoustic impedance. During voice calls, the valve opens to allow natural sound transmission. This dynamic behavior resolves the contradiction by temporally separating the functions of sound blocking and sound transmission.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The acoustic impedance and sound transmission parameters are dynamically adjusted by changing the valve position. When closed, the parameters are optimized for preventing sound leakage during music playback. When open, the parameters are optimized for sound transmission during voice calls. This parameter adjustment resolves the contradiction between sound leakage prevention and sound transmission.

Inventive Principle:
Principle #35Parameter changes

3Object-generated harmful factors

If the closing element is positioned in the sound channel to block sound, then sound blocking is effective, but acoustic filtering is affected

Engineering Contradiction:
Improvesound blockingVSAvoidacoustic filtering
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The patent extracts the closing element from the sound channel path when blocking is required. Instead of placing the closing element directly in the sound channel, the valve is positioned at the vent opening, which is separate from the main sound channel. This extraction approach allows effective sound blocking at the vent while preserving the acoustic filtering properties of the sound channel.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The vent structure serves as an intermediary between the sound channel and the external environment. By placing the valve at the vent opening rather than directly in the sound channel, the patent uses the vent as a mediator to block sound while preserving the acoustic filtering characteristics of the sound channel. This intermediary approach resolves the contradiction between sound blocking effectiveness and acoustic filtering reliability.

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

Effectively manages sound transmission by attenuating unwanted frequencies, maintaining acoustic impedance and filtering properties, enhancing sound quality and comfort by reducing noise leakage and impedance changes in the ear canal.

Implementation Method 1

the valve being configured to, in the first position, attenuate all frequencies within the interval of 700-2000Hz no more than 6dB, the valve being configured to, in the second position, attenuate all frequencies within the interval of 700-2000Hz at least 10dB

Methodology Applied
Scientific EffectAcoustic filtering: Filter (physical)

Data Source

PatentEP3471433B1A personal hearing device
Publication Date: 2022.10.26 SONION NEDERLAND BV
  • EP3471433B1 patent drawingFigure 1~4
  • EP3471433B1 patent drawingFigure 5~6
  • EP3471433B1 patent drawingFigure 7

AI summary

A personal hearing device with an outer housing and a sound path with a length of 1-24mm, a diameter of 0.5-6mm, a roll of frequency of at least 500Hz and with a valve configured to open and close the sound path. The sound path has suitable acoustical properties to act as a sound passage for open/closed hearing aids or hearables. The valve is selected to have a small influence on the acoustical properties of the remaining portions of the sound path.