Bone Conduction Noise Cancellation for Open-Ear Wearables

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Solution Overview

Problem

Wearable computing devices, such as head-mounted displays, face challenges in effectively canceling ambient noise using bone conduction technology, as they often leave the wearer's ears exposed to unwanted sound.

Innovation Solution

A method and system where a wearable computing device processes ambient sound signals to generate a noise-cancelling audio signal that is out of phase with the ambient noise, using wearer-specific parameters to effectively cancel ambient sound by causing a bone conduction transducer to vibrate and transmit this noise-cancelling sound to the wearer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If bone conduction transducer is used to provide audio to wearer, then audio transmission is achieved, but ambient noise cancellation is insufficient

Engineering Contradiction:

Improveaudio transmission reliabilityVSAvoidambient noise exposure

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an intermediary noise cancellation signal that is generated by the wearable device and transmitted through the bone conduction transducer. This intermediary signal acts as a mediator between the ambient noise and the wearer's auditory system, canceling out harmful ambient noise while allowing desired audio to pass through the bone conduction path.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system performs preliminary anti-action by detecting ambient noise before it reaches the wearer's ear and generating an opposing sound wave through the bone conduction transducer. This pre-emptive cancellation prevents the harmful ambient noise from affecting the wearer, while the desired audio signal is simultaneously transmitted through the same bone conduction path.

Inventive Principle:

Principle #9Preliminary anti-action

2Ease of operation

If open ear design is used for wearable device, then comfort and visibility are improved, but noise cancellation effectiveness deteriorates

Engineering Contradiction:

Improvewearer comfortVSAvoidambient noise exposure

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the traditional mechanical ear canal blocking method with a bone conduction-based noise cancellation system. Instead of physically obstructing the ear canal with earphones or earplugs, the system uses bone conduction transducers to transmit both desired audio and noise cancellation signals directly through the skull, maintaining open ear design while achieving effective noise cancellation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Object-affected harmful factors

If noise cancellation signal is generated, then ambient noise is reduced, but signal processing complexity increases

Engineering Contradiction:

Improveambient noise exposureVSAvoidsignal processing complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent merges the desired audio signal and the noise cancellation signal into a single bone conduction transmission path. By combining these signals before transmission through the bone conduction transducer, the system reduces the number of separate processing channels and simplifies the overall signal processing architecture compared to using separate paths for audio and noise cancellation.

Inventive Principle:

Principle #5Merging (Combining)

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 approach significantly reduces ambient noise exposure for the wearer, allowing them to perceive desired sounds while minimizing ambient noise interference, enhancing the usability of wearable computing devices in noisy environments.

Implementation Method 1

causing a bone conduction transducer (BCT) coupled to the wearable computing device to vibrate so as to provide to an ear a noise-cancelling sound representative of the noise-cancelling audio signal

Methodology Applied

Scientific EffectBone conduction: Vibration

Implementation Method 2

receiving, by at least one input transducer coupled to a wearable computing device, a first audio signal associated with ambient sound from an environment of the wearable computing device

Methodology Applied

Scientific EffectAcoustic transduction: Sound

Data Source

PatentUS9589559B2Methods and systems for implementing bone conduction-based noise cancellation for air-conducted sound

Publication Date: 2017.03.07 GOOGLE LLC

AI summary

A wearable computing device can receive, via at least one input transducer, a first audio signal associated with ambient sound from an environment of the device. The device can then process the first audio signal so as to determine a second audio signal that is out of phase with the first audio signal and effective to substantially cancel at least a portion of the first audio signal. The device may then generate a noise-cancelling audio signal based on the second audio signal, based on a third audio signal, and based on one or more wearer-specific parameters, where the third audio signal is representative of a sound to be provided by the device. The device may then cause a bone conduction transducer (BCT) to vibrate so as to provide to an ear a noise-cancelling sound effective to substantially cancel at least a portion of the ambient sound.