Expandable Bubble Acoustic Coupler for Ear Bud Impedance Matching
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Solution Overview
Problem
Conventional personal listening devices, such as hearing aids and ear buds, occlude the ear canal, leading to reduced discernability and increased listener fatigue due to unnatural sound pressure and vibrational aberrations, which can cause hearing damage and impair the ability to perceive ambient sounds.
Innovation Solution
The use of an expandable bubble portion that provides a variable impedance matching acoustic seal, allowing the ear to maintain its natural resonance and reducing the impact of transducer vibrations on the tympanic membrane, while enabling the transmission of audio content in a manner that utilizes the ear's full capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ear canal is occluded with an audio transducer to create a closed sound-vibration chamber, then the transducer can be directly coupled to the tympanic membrane, but the ear's natural resonance and discernability are degraded
Solution Approach 1:
The patent introduces an acoustic coupler as an intermediary component between the audio transducer and the ear canal. This coupler includes a flexible diaphragm and acoustic cavity that mediates the transmission of sound vibrations, allowing the transducer to be positioned away from the tympanic membrane while still effectively transmitting audio signals. The intermediary coupler preserves the ear's natural resonance by avoiding direct occlusion and rigid coupling.
Solution Approach 2:
The patent replaces the conventional rigid mechanical coupling system with an acoustic field-based transmission system. Instead of directly mechanically coupling the transducer to the tympanic membrane through a closed chamber, the invention uses acoustic waves transmitted through air or fluid media within the coupler structure. This substitution maintains vibration transmission while preserving the natural acoustic environment of the ear canal.
2Ease of manufacture
If conventional magnetic moving coil and moving armature devices are used with large diaphragm excursions, then the transducer output is easily observed, but the tympanic membrane is forced to emulate these gross excursions causing hearing damage
Solution Approach 1:
The patent segments the acoustic transmission path into separate functional zones: the transducer diaphragm operates in one zone with large excursions for efficient sound generation, while the acoustic coupler and ear canal form separate zones that transmit these vibrations more gently to the tympanic membrane. The acoustic cavity and flexible diaphragm act as intermediate transmission elements that decouple the large transducer movements from the delicate ear drum movements.
Solution Approach 2:
The acoustic coupler structure provides beforehand cushioning by using compliant flexible diaphragms and acoustic cavities to soften and distribute the vibrations before they reach the tympanic membrane. The flexible diaphragm acts as a cushion that absorbs and distributes the mechanical stress, preventing direct transmission of harmful gross excursions to the ear drum while still conveying the audio signal.
3Reliability
If the ear canal is closed to create a pressure coupling chamber, then the transducer can be directly coupled to the tympanic membrane, but the natural vibrational modes of the tympanic membrane are changed
Solution Approach 1:
The patent employs dynamic, flexible components including a flexible diaphragm and expandable acoustic cavity that can adapt their configuration based on acoustic pressure variations. This dynamic structure allows the coupler to maintain effective vibration transmission while accommodating the natural vibrational modes of the tympanic membrane, preventing rigid constraint of the ear drum's natural movement patterns.
Solution Approach 2:
The acoustic coupler utilizes changes in acoustic parameters including pressure, volume, and impedance within the acoustic cavity to optimize transmission. The expandable cavity can change its volume in response to acoustic pressure, and the flexible diaphragm adjusts its stiffness based on the acoustic environment. These parameter changes allow the system to maintain effective coupling while preserving the natural vibrational characteristics of the tympanic membrane.
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 enhances audio fidelity, reduces listener fatigue, and allows for better environmental awareness by improving discernability and mixing music or voice communications with outside sounds, while minimizing the risk of hearing damage.
Implementation Method 1
The expandable bubble portion provides a variable impedance matching acoustic seal
Implementation Method 2
allowing the ear to maintain its natural resonance
Implementation Method 3
a flexible diaphragm that transduces acoustic pressure variations
Implementation Method 4
an acoustic cavity that transmits sound waves
Data Source
AI summary
The disclosed methods and devices incorporate a novel expandable bubble portion which provides superior fidelity to a listener while minimizing listener fatigue. The expandable bubble portion may be expanded through the transmission of low frequency audio signals or the pumping of a gas to the expandable bubble portion. In addition, embodiments of the acoustic device may be adapted to consistently and comfortably fit to any ear, providing for a variable, impedance matching acoustic seal to both the tympanic membrane and the audio transducer, respectively, while isolating the sound-vibration chamber within the driven bubble. This reduces the effect of gross audio transducer vibration excursions on the tympanic membrane and transmits the audio content in a manner which allows the ear to utilize its full inherent capabilities.