Acoustically Active Headrest with Integrated Microphone
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Solution Overview
Problem
Existing systems for reducing noise in vehicles, such as those in GB 2 360 900 A and US 2010/014110 A1, face challenges in positioning microphones close to the user's head, leading to inconvenient and potentially hazardous arrangements, while also failing to enhance acoustic properties and safety simultaneously.
Innovation Solution
An acoustically active headrest with integrated unidirectional microphones and loudspeakers, where the microphone's principal receiving direction intersects with the user's ear positions and loudspeakers radiate sound energy at an angle greater than 30 degrees from the microphone's direction, integrated into a concave-shaped front surface, along with an evaluation circuit for noise control and audio processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the microphone is mounted on a flexible arm, hinged holder, rigid boom, or pivotable wing extending into the user direction, then acoustic properties are improved, but convenience deteriorates and safety risk increases
Solution Approach 1:
The microphone is integrated directly into the headrest body structure, merging the acoustic measurement function with the existing headrest component. This eliminates the need for separate mounting mechanisms (flexible arms, booms, etc.) while maintaining close proximity to the user's head for superior acoustic measurement.
2Measurement precision
If the microphone is mounted on a flexible arm, hinged holder, rigid boom, or pivotable wing extending into the user direction, then acoustic properties are improved, but safety risk increases
Solution Approach 1:
The microphone is integrated directly into the headrest body structure, merging the acoustic measurement function with the existing headrest component. This eliminates the need for separate mounting mechanisms (flexible arms, booms, etc.) while maintaining close proximity to the user's head for superior acoustic measurement.
3Reliability
If the loudspeaker is positioned close to the microphone, then noise reduction effectiveness is improved, but acoustic interference increases
Solution Approach 1:
The headrest front surface is divided into different functional zones: the microphone is positioned in one local area optimized for acoustic reception, while the loudspeaker is positioned in a different local area optimized for sound transmission. This spatial separation of functions reduces acoustic interference while maintaining noise reduction effectiveness.
Solution Approach 2:
The microphone and loudspeaker are positioned asymmetrically relative to each other on the headrest front surface, with the microphone oriented toward the user's ear and the loudspeaker oriented at an angle greater than 30 degrees from the microphone's receiving direction. This asymmetric arrangement minimizes acoustic interference while maintaining effective noise control.
4Ease of manufacture
If the headrest front surface is made flat, then manufacturing is simplified, but acoustic distribution to user ears is reduced
Solution Approach 1:
The headrest front surface features an inward-curving shape that extends partly around the longitudinal axis of the user's head. This curved geometry naturally directs acoustic waves toward the user's ears, improving sound distribution and acoustic measurement quality compared to a flat surface, while remaining manufacturable.
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 configuration provides improved acoustic properties and safety by effectively reducing noise while maintaining user convenience, with the ability to perform active noise control, dynamic equalization, and other audio processing functions.
Implementation Method 1
a microphone that has a maximum sensitivity to sounds from a principal receiving direction and that is integrated into the front surface of the headrest body such that the principal receiving direction intersects with one of the preferential positions of the user's ears
Implementation Method 2
a loudspeaker integrated into the headrest body, wherein the loudspeaker has a principal transmitting direction into which it radiates maximum sound energy, the loudspeaker being arranged such that its principal transmitting direction is at an angle greater than 30 degrees from the principal receiving direction of the microphone
Implementation Method 3
The front surface of the headrest has an inward-curving shape extending partly around the longitudinal axis of the user's head. The inward-curving shape has two planar end sections and an intermediate section
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
An acoustically active headrest comprises a headrest body with a front surface configured to support a user's head, thereby defining preferential positions of the user's ears, and a microphone that has a maximum sensitivity to sounds from a principal receiving direction and that is integrated into the front surface of the headrest body such that the principal receiving direction intersects with one of the preferential positions of the user's ears.