Offset Microphone Array for Implantable Hearing Signal Processing
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Solution Overview
Problem
Implanted hearing devices face challenges in achieving a desired signal-to-noise ratio with adequate sensitivity across a normal hearing range of acoustic frequencies due to the limitations of single microphone systems.
Innovation Solution
An implantable auditory stimulation system utilizing multiple microphones positioned at differing subcutaneous locations with varying acoustic and vibrational characteristics, allowing for beamforming and directionality through the combination of their output signals, and employing processors for signal processing and generation of a drive signal to stimulate the auditory system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single microphone is used in the implanted hearing device, then the device complexity is reduced, but the signal-to-noise ratio and sensitivity across the normal hearing range deteriorate
Solution Approach 1:
The patent divides the audio signal acquisition function into multiple independent microphones positioned at different locations within the implanted device. Each microphone captures acoustic signals from slightly different positions, and their outputs are processed separately before being combined. This segmentation allows the system to achieve better signal-to-noise ratio and frequency response characteristics without requiring a single complex microphone element.
2Adaptability or versatility
If multiple microphones are positioned at offset subcutaneous locations, then beamforming and directionality are enabled, but the device complexity and surgical implantation complexity increase
Solution Approach 1:
The patent positions multiple microphones at offset locations within the implanted device housing, creating spatial separation in three-dimensional space. This spatial arrangement enables the system to perform beamforming and directional signal processing by exploiting the different acoustic paths and time delays that signals from different directions experience. The offset positioning transforms a single-point measurement into a spatially-resolved measurement system.
3Object-affected harmful factors
If microphones are isolated from skull-borne vibrations, then noise interference is reduced, but the coupling efficiency for low frequency sounds may deteriorate
Solution Approach 1:
The patent employs different microphone types with different sensitivity characteristics at different locations within the implanted device. Some microphones are positioned and oriented to be more sensitive to airborne acoustic signals, while others may have different directional characteristics. This local differentiation of microphone properties allows the system to optimize for different frequency ranges and signal types, reducing the trade-off between noise isolation and low-frequency sensitivity.
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
Enhances signal processing and sensitivity across a broader frequency range, improving sound perception by simulating natural hearing and reducing noise interference, particularly by isolating microphones from skull-borne vibrations and utilizing different sensitivity ranges for optimal acoustic amplification.
Implementation Method 1
a first microphone operative to transcutaneously receive acoustic signals and generate a first microphone output signal in response thereto, and a second microphone operative to transcutaneously receive acoustic output signals and generate a second microphone output signal
Data Source
AI summary
An improved implantable auditory stimulation system includes two or more implanted microphones for transcutaneous detection of acoustic signals. Each of the implanted microphones provides an output signal. The microphone output signals may be combinatively utilized by an implanted processor to generate a signal for driving an implanted auditory stimulation device. The implanted microphones may be located at offset subcutaneous locations and/or may be provided with different design sensitivities, wherein combinative processing of the microphone output signals may yield an improved drive signal. In one embodiment, the microphone signal may be processed for beamforming and/or directionality purposes.