Dual Transducer Shared Diaphragm Drift Control
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Solution Overview
Problem
Current directional microphones for hearing aids face challenges in controlling short and long-term drift due to changes in membrane tension, which affects their accuracy and reliability over time.
Innovation Solution
A dual transducer design where both vibration sensors share the same diaphragm, with separate chambers and a dividing portion that allows for independent operation and minimal sound transfer between them, using a resilient element to maintain consistent diaphragm tension and prevent drift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two separate microphones are used in directional microphones, then sound detection capability is improved, but drift occurs due to changes in membrane tension over time
Solution Approach 1:
The patent merges the diaphragms of two separate microphones into a single shared diaphragm structure. This ensures that both microphones experience identical membrane tension changes over time, causing them to drift together rather than independently. The shared diaphragm eliminates differential aging and tension variations between the two sensing elements, maintaining their relative calibration and reducing drift in the differential signal output.
2Ease of manufacture
If neighbouring membranes are paired in production matrix, then manufacturing is simplified, but drift control remains insufficient
Solution Approach 1:
Instead of pairing neighbouring membranes in a production matrix, the patent uses a single shared diaphragm that serves both microphones. This approach maintains manufacturing simplicity while providing superior drift control, as the entire diaphragm acts as one unified sensing element that ages uniformly, ensuring both microphones experience identical environmental and mechanical conditions.
3Reliability
If a single shared diaphragm is used for both vibration sensors, then diaphragm tension drift is reduced, but chamber separation is required to maintain independent operation
Solution Approach 1:
The patent segments the internal volume into two separate chambers while using a single continuous diaphragm that spans both chambers. The diaphragm is mechanically continuous but acoustically isolated, with each chamber providing independent acoustic access to different portions of the same diaphragm. This segmentation allows independent operation and signal processing for each microphone while maintaining the benefits of a shared diaphragm structure.
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 ensures that the microphones remain matched and functional over time, reducing the impact of diaphragm tension changes and maintaining accurate sound detection within the audible frequency range without significant attenuation.
Implementation Method 1
a diaphragm connected to both the first and second vibration sensor, wherein: a first chamber is delimited at least partly by a first part of the housing and a first part of the diaphragm, the first vibration sensor being configured to detect vibration of the first part of the diaphragm
Implementation Method 2
Vibration sensors are widely used in, for example, the hearing aid industry. Such sensors may be based on a number of different technologies, such as the electret principle, moving magnet, moving coil, moving armature, or the like.
Data Source
AI summary
The invention relates to a transducer comprising a housing having a first and a second sound input, a first and a second vibration sensors configured to convert vibration to an output, and a diaphragm connected to both the first and second vibration sensor.