Bone Conduction Microphone Gas Cavity Noise Isolation
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Solution Overview
Problem
Voice input in noisy environments is challenging due to ambient sound interference, leading to undetected or false triggering of voice commands in wearable computing devices.
Innovation Solution
A bone conduction microphone (BCM) is integrated into wearable devices, featuring a gas-filled cavity with an elastic portion that transfers vibrations from the bone structure to the gas, allowing the microphone to isolate speech from ambient noise, thereby enhancing voice input recognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional microphone is used in wearable devices, then the device structure remains simple, but voice input detection is unreliable in noisy environments due to ambient sound interference
Solution Approach 1:
The microphone system is segmented into distinct functional components: an elastic portion for vibration reception, a gas-filled cavity for vibration transmission, and a microphone element for signal conversion. This segmentation allows each component to be optimized for its specific function, improving voice detection reliability while maintaining manageable structural complexity
Solution Approach 2:
Gas is introduced as an intermediary medium between the elastic portion and the microphone element. This gas-filled cavity acts as a mediator that transmits vibrations from the elastic portion to the microphone while isolating the microphone from direct exposure to ambient noise, thereby improving voice input detection in noisy environments
2Measurement precision
If the microphone is directly exposed to the exterior, then the structure remains simple, but ambient sound interferes with voice command recognition
Solution Approach 1:
The microphone element is extracted from direct exposure to the external environment and placed within a gas-filled cavity. This extraction removes the microphone from the harmful ambient sound field while maintaining its ability to detect voice signals through the elastic portion and gas medium, thereby improving measurement precision
Solution Approach 2:
The enclosing structure exhibits local quality differentiation: the elastic portion is designed to be flexible for vibration reception, while the rest of the enclosing structure provides acoustic isolation. This localized functional differentiation allows the structure to simultaneously enable voice signal transmission and block ambient noise interference
3Object-affected harmful factors
If a gas-filled cavity with elastic portion is used, then voice isolation from ambient noise is improved, but the device complexity increases
Solution Approach 1:
The elastic portion, gas-filled cavity, and microphone element are merged into an integrated bone conduction microphone assembly. This merging combines multiple protective and functional elements into a unified structure that effectively isolates voice signals from ambient noise while presenting a compact, manageable device complexity
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
The BCM effectively isolates the user's voice from ambient sounds, improving voice input detection and reducing false triggers in noisy environments.
Implementation Method 1
an elastic material is moveable to transfer vibration from an exterior source to gas within the cavity
Implementation Method 2
the vibration transferred from the exterior source to the gas in the cavity is detectable by the microphone
Data Source
Figure 1A
Figure 1B
Figure 2A~2B
AI summary
The present application describes bone conduction microphone (BCM) systems and applications thereof. An example apparatus includes: (a) an enclosing structure having a cavity therein, wherein a first portion of the enclosing structure is formed by an elastic material, and wherein the elastic material is moveable to transfer vibration from an exterior source to gas within the cavity; and (b) a microphone coupled to the enclosing structure and located within the gas-filled cavity, wherein gas in the cavity separates the microphone from the first portion of the enclosing structure, such that the vibration transferred from the exterior source to the gas in the cavity is detectable by the microphone.