Off-Ear Speaker Noise Cancellation for HMD Fan Noise
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Solution Overview
Problem
Head-mounted displays (HMDs) with off-ear speakers produce unpleasant fan noise that interferes with the user's ability to hear audio content, particularly when electronic components are running at maximum performance.
Innovation Solution
Implement active noise reduction techniques using a processor to determine audio parameters based on fan noise characteristics, outputting sound via off-ear speakers to cancel the fan noise at the user's ears, while conserving power resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If fans are operated to cool electronic components at maximum performance, then the electronic components are prevented from overheating, but fan noise is produced that interferes with audio content
Solution Approach 1:
The patent captures the harmful fan noise using microphones and converts it into a beneficial cancellation signal through active noise reduction. The processor analyzes the fan noise characteristics and generates an inverted phase signal that, when played through the off-ear speakers, destructively interferes with the original fan noise, effectively canceling it out while the fan continues to cool the electronic components.
Solution Approach 2:
The patent introduces an intermediary active noise reduction system between the fan noise source and the user's ears. This system includes microphones that capture fan noise, a processor that analyzes and inverts the noise signal, and off-ear speakers that emit the inverted signal. This intermediary system allows the fan to operate at full cooling capacity while preventing the noise from reaching the user.
2Object-generated harmful factors
If active noise reduction is implemented to cancel fan noise, then fan noise is reduced at the user's ears, but additional power is consumed by the noise reduction system
Solution Approach 1:
The patent makes the off-ear speakers multi-functional by using them for both audio content playback and active noise reduction. The same speakers that deliver game audio or music are also utilized to emit the inverted phase cancellation signal. This eliminates the need for separate noise-canceling hardware, thereby avoiding additional power consumption from dedicated noise reduction components.
Solution Approach 2:
The system uses the HMD's existing audio output components (off-ear speakers) to serve the dual purpose of delivering audio content and performing active noise reduction. The noise cancellation function is integrated into the existing audio pathway, allowing the system to cancel fan noise using its own built-in resources without requiring external power-intensive equipment.
3Ease of operation
If off-ear speakers are used to provide audio content, then users can hear audio content, but fan noise is also audible to the user
Solution Approach 1:
The patent applies local quality by directing the noise cancellation signal specifically to the user's ears through the off-ear speakers, while leaving the rest of the environment unchanged. The active noise reduction is localized to the acoustic field near the user's ears, allowing audio content to be played clearly in that specific location while fan noise is canceled only in the user's immediate auditory space.
Solution Approach 2:
The off-ear speakers serve as an intermediary device that delivers both audio content and noise cancellation signals to the user's ears. By positioning the speakers off-ear (near but not in the ear canal), the system creates a localized acoustic zone where both the desired audio content and the anti-noise signal can be delivered effectively, while the fan noise cancellation occurs specifically in the user's auditory experience rather than throughout the entire environment.
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 the audio experience by reducing or eliminating fan noise, allowing users to operate HMDs at maximum performance without hearing the cooling fan noise, while being energy-efficient.
Implementation Method 1
outputting sound via off-ear speakers to cancel the fan noise at the user's ears
Data Source
AI summary
Described herein are active noise reduction (ANR) techniques for reducing noise produced by a fan(s) of a head-mounted display (HMD). An example process may include receiving data indicative of a noise that is being produced by the fan(s), determining, based at least in part on the data and using a model(s), one or more audio parameter values, and outputting, via one or more off-ear speakers of the HMD, a sound(s) having one or more audio characteristics based at least in part on the one or more audio parameter values to reduce the noise produced by the fan(s) at a location(s) of an ear(s) of the user of the HMD.