Cartilage Conduction Audio System for Eyewear
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Solution Overview
Problem
Existing audio systems in VR, AR, and MR eyewear devices face challenges in providing full-frequency audio reproduction while keeping the ear canal open, maintaining ergonomics, reducing power consumption, and minimizing crosstalk.
Innovation Solution
A cartilage conduction audio system that uses a transducer assembly coupled to the back of the ear to vibrate the auricle, generating acoustic pressure waves, and an acoustic sensor to detect and adjust these waves for individualized audio response, allowing the ear canal to remain open.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If traditional headphones or earbuds are used to provide audio, then audio reproduction is achieved, but the ear canal is blocked preventing ambient sound perception
Solution Approach 1:
The patent uses the auricle (outer ear) as an intermediary structure to transmit audio vibrations to the ear canal. Instead of placing transducers directly in the ear canal, the system vibrates the auricle which then acts as a natural amplifier and transmitter of sound waves into the ear canal, allowing ambient sound to pass through while delivering audio content.
Solution Approach 2:
The patent replaces the traditional acoustic coupling method (direct sound wave transmission through ear canal occlusion) with a mechanical vibration approach. Transducers are positioned to mechanically vibrate the auricle cartilage, which then generates acoustic pressure waves within the ear canal, substituting the need for physical ear canal blockage.
2Ease of operation
If bone conduction transducers are used to keep ear canal open, then ambient sound perception is maintained, but device size and power consumption increase
Solution Approach 1:
The patent applies local quality by positioning small transducers at specific locations on the auricle where they can efficiently couple with the cartilage structure. The transducers are placed in proximity to the ear canal entrance, allowing localized vibration of the auricle without requiring a large overall device structure.
Solution Approach 2:
The patent transitions from traditional in-ear or over-ear positioning to a behind-the-ear configuration where transducers contact the auricle. This spatial repositioning in another dimension (behind the ear rather than in or over it) allows for a more compact device form factor while maintaining ear canal openness.
3Use of energy by moving object
If bone conduction transducers are used to provide audio, then audio transmission is achieved, but crosstalk between ears occurs
Solution Approach 1:
The patent extracts the audio transmission function from the traditional bone conduction pathway (skull vibrations) and relocates it to the auricle cartilage. By isolating the vibration source to the outer ear structure rather than transmitting through the skull, the system prevents audio signals from crossing to the opposite ear through bone conduction.
Solution Approach 2:
The patent uses the auricle as a natural acoustic copy mechanism. The transducers create vibrations that are copied and amplified by the auricle's natural acoustic properties, generating pressure waves that enter the ear canal in a controlled manner, preventing unauthorized audio leakage to the other ear.
4Use of energy by moving object
If traditional audio systems are used in eyewear, then audio reproduction is achieved, but ergonomics and comfort are compromised
Solution Approach 1:
The patent segments the audio system into separate components: transducers positioned behind the ear, auricle contact points, and ear canal interface. This segmentation allows each component to be optimized independently, with the transducers placed in an ergonomically favorable location behind the ear rather than on the ear canal or headband.
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 solution reduces crosstalk, power consumption, and size, enhancing comfort and immersion by using the auricle as a speaker, providing a similar audio experience across users while maintaining ear canal openness.
Implementation Method 1
The transducer assembly is coupled to a back of an auricle of the user to vibrate the auricle over a frequency range, creating an acoustic pressure wave
Data Source
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AI summary
An audio system includes a transducer assembly, an audio sensor, and a controller. The transducer assembly is coupled to a back of an auricle of an ear of the user. The transducer assembly vibrates the auricle over a frequency range to cause the auricle to create an acoustic pressure wave in accordance with vibration instructions. The acoustic sensor detects the acoustic pressure wave at an entrance of the ear of the user. The controller dynamically adjusts a frequency response model based in part on the detected acoustic pressure wave, updates the vibration instructions using the adjusted frequency response model, and provides the updated vibration instructions to the transducer assembly.