Hearing Aid Microphone Coupling for Omnidirectional Mode Switching

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Solution Overview

Problem

Existing hearing devices struggle to maintain omnidirectional directivity when microphone arrangements are unforeseen or when one microphone is covered, such as by hair, leading to unintended directional characteristics and potential artifacts during sound detection.

Innovation Solution

A hearing device with a microphone arrangement of at least two microphones and a coupling mechanism that allows each microphone to be coupled to both inputs, enabling the generation of an omnidirectional directional characteristic using a single microphone, and allowing seamless switching between directional and omnidirectional modes without artifacts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a microphone arrangement with specific alignment is used to achieve omnidirectional directivity, then omnidirectional sound detection is improved, but the system becomes sensitive to unexpected microphone positions or coverage by hair

Engineering Contradiction:

Improveomnidirectional directivityVSAvoidrobustness to microphone misalignment

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic switching between different operational modes (omnidirectional and directional) based on real-time assessment of microphone alignment and functionality. The system adapts its directivity characteristics by selecting appropriate signal processing paths, allowing it to maintain reliable operation whether microphones are correctly aligned or covered/misaligned.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes processing parameters (signal weighting factors, delay times, and directivity mode selection) based on the operational state of the microphones. By adjusting these parameters dynamically, the system maintains omnidirectional directivity when microphones are properly positioned while transitioning to alternative processing modes when microphones are covered or misaligned, thus resolving the contradiction between reliability and adaptability.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If directional sound detection is implemented using multiple microphones, then directional selectivity is improved, but artifacts may occur during transitions between directional and omnidirectional modes

Engineering Contradiction:

Improvedirectional selectivityVSAvoidtransition smoothness

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent applies preliminary time alignment (delay adjustment) to microphone signals before they are combined. By pre-synchronizing the signals from multiple microphones based on their expected arrival times, the system prevents phase-related artifacts during mode transitions. This preliminary action ensures smooth transitions between directional and omnidirectional modes while maintaining directional selectivity.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses an intermediary processing stage that smoothly blends between omnidirectional and directional modes. Rather than abrupt switching, the intermediary processing allows for gradual transitions by combining signals with appropriate weighting, preventing artifacts while maintaining the ability to achieve directional selectivity when needed.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If a single microphone is used to generate omnidirectional directivity, then the system becomes more robust to microphone coverage, but the directional effect generation capability is reduced

Engineering Contradiction:

Improverobustness to microphone coverageVSAvoiddirectional effect accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent designs the microphone system to be multi-functional, where each microphone can serve multiple roles. When one microphone is covered, the system can universally use the remaining uncovered microphone(s) to generate omnidirectional directivity. The same signal processing device that handles multi-microphone directional processing also handles single-microphone omnidirectional processing, making the system versatile and robust while maintaining directional effect capability through adaptive mode selection.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentEP2373065B2Hearing aid and method for creating an omnidirectional alignment characteristic

Publication Date: 2018.10.03 SIVANTOS PTE LTD

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AI summary

The device has a microphone array including two microphones (2, 2'). An apparatus (10) produces a directivity of the microphone array, and includes two inputs (12, 14). A coupling device (42) couples one of the microphones to one of the inputs, and couples other microphone to other input of the apparatus, respectively. The coupling device simultaneously couples the microphones to both inputs of the apparatus, respectively. The coupling device allows selective interruption of a signal path from the latter microphone to the apparatus for producing the directional characteristic.