Mixed-Reality Headset Audio Design with Foam and Fluidic Noise Control
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Solution Overview
Problem
MR headsets face challenges in maintaining accurate audio performance due to interactions with lighting conditions, forced cooling noise interference, and functional requirements like strap-fastening openings, which disrupt immersion and interaction accuracy.
Innovation Solution
Integration of floodlight-emitting diodes to illuminate interaction spaces, a speaker design with foam inserts to minimize intermodulation, a fan system with a fluidic channel and expansion chamber to reduce noise interference, and strategically placed microphones to detect user audio while minimizing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a fan is used for forced cooling of electronic components, then thermal management is improved, but noise interference with audio content deteriorates
Solution Approach 1:
The patent extracts the harmful acoustic resonance from the cooling system by introducing a resonator that specifically targets and eliminates fan-generated noise at its resonant frequencies, separating the cooling function from the noise generation problem
Solution Approach 2:
The patent converts the harmful fan noise into a beneficial solution by using the resonator to absorb acoustic energy at resonant frequencies, transforming the noise problem into a targeted acoustic filtering mechanism that improves overall audio quality
2Ease of operation
If strap-fastening openings are provided in the housing, then ease of operation is improved, but audio performance deteriorates due to intermodulation
Solution Approach 1:
The patent extracts the harmful acoustic intermodulation from the cavity by introducing foam inserts that absorb and dampen unwanted acoustic waves, separating the structural opening function from the acoustic interference problem
Solution Approach 2:
The patent applies local acoustic treatment by placing foam inserts specifically in regions where acoustic intermodulation occurs, providing targeted acoustic damping without affecting the overall structural integrity or strap fastening functionality
3Ease of operation
If microphones are positioned near aperture openings for audio detection, then ease of operation is improved, but measurement precision deteriorates due to noise interference
Solution Approach 1:
The patent extracts the harmful noise interference from the microphone environment by using the resonator and foam inserts to eliminate fan noise and acoustic intermodulation, allowing microphones to be positioned in acoustically favorable locations without sacrificing detection accuracy
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 audio performance and interaction accuracy by optimizing lighting conditions, reducing noise interference, and ensuring effective audio detection, thereby improving the immersive experience.
Implementation Method 1
an inner surface of the fluidic channel defines a set of perforations, wherein the set of perforations is configured to receive acoustic waves associated with resonant frequencies of the fan
Implementation Method 2
an expansion chamber that surrounds the inner surface of the fluidic channel, the expansion chamber having a back volume that causes a bias flow across the set of perforations of the inner surface of the fluidic channel
Implementation Method 3
a speaker housed within the cavity, the speaker being positioned adjacent to a foam insert for minimizing (e.g., attenuating, reducing) intermodulation of the speaker within the cavity during presentation of the audio content
Implementation Method 4
the first opening of the aperture is adjacent to an exhausting side of the fan, such that exhaust from the fan causes a grazing flow to enter the first opening and exit the second opening, thereby forming a fluidic channel across the aperture
Data Source
AI summary
An example MR headset includes a housing with electronic components for presenting MR content, where the housing is configured to attach to a strap thereby forming a cavity, and defines an aperture, including a first opening on a first side of the MR headset and a second opening on a second side of the MR headset. The MR headset includes a speaker within the cavity positioned for minimizing intermodulation of the speaker within the cavity. The housing includes a fan to cool the electronic components and minimize noise interference. The MR headset includes an expansion chamber surrounding the inner surface of the fluidic channel that causes bias flow across the perforations. The MR headset includes microphones distributed along an outer surface of the housing for detecting audio content from a user, and each respective microphone is separated from the first and second opening by at least an audial-interference threshold distance.