Sound pickup device
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Solution Overview
Problem
Existing sound pickup devices struggle to satisfactorily capture sound from a seated person's side due to inadequate directional control and interference from unwanted sound sources.
Innovation Solution
A sound pickup device with a headrest or seat back featuring a recessed opening, where two nondirectional microphones are positioned at different distances from the seating surface, creating a phase difference to enhance directivity and block unwanted sounds, thereby improving sound capture from the seated person's side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single nondirectional microphone is used in the headrest, then the device structure is simple, but the sound pickup directionality is poor and unwanted sounds from all directions are captured
Solution Approach 1:
The patent divides the sound pickup function into multiple independent nondirectional microphones arranged at different positions and depths within the headrest. By segmenting the pickup function across multiple simple microphones rather than using one complex directional microphone, the system achieves directional control through spatial arrangement while keeping individual components simple
Solution Approach 2:
The patent introduces a depth dimension by placing microphones at different distances from the seating surface (different Z-depths) in addition to horizontal positioning. This multi-dimensional arrangement creates phase differences for sounds from different directions, enabling directional discrimination without requiring complex individual microphones
2Measurement precision
If microphones are placed closer to the seating surface for better sound capture, then sound pickup sensitivity improves, but interference from unwanted sound sources increases
Solution Approach 1:
The patent creates different local acoustic environments for each microphone by positioning them at different depths and locations within the headrest structure. Each microphone experiences a unique sound field characteristic, allowing the system to distinguish between wanted and unwanted sounds through comparative analysis of these locally differentiated signals
Solution Approach 2:
The patent converts the potentially harmful effect of unwanted sounds entering the headrest into a beneficial discrimination mechanism. By having microphones at different positions and depths, unwanted sounds from various directions create distinct phase relationships that can be identified and filtered out, transforming interference into a useful directional cue
3Device complexity
If multiple microphones are arranged at the same position, then the device structure is simple, but phase difference for directivity control cannot be achieved
Solution Approach 1:
The patent adds the depth dimension (distance from seating surface) as a critical variable in microphone arrangement. By positioning microphones at different Z-depths within the headrest while maintaining relatively simple horizontal placement, the system achieves the necessary path length differences for phase-based directivity control without overly complicating the overall structure
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
The device effectively picks up sound from the seated person while minimizing interference from other directions, ensuring clear and focused sound capture through the use of phase difference directivity control and strategic microphone placement.
Implementation Method 1
the first sound pickup means and the second sound pickup means are disposed so that distances to the first sound pickup means and the second sound pickup means from a portion, closest to the seating surface, of the opening of the headrest are different from each other... capable of detecting the sound from the sound source with a phase difference between the sound arriving at the first sound pickup means and the sound arriving at the second sound pickup means
Data Source
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AI summary
There is provided a sound pickup device capable of satisfactorily picking up sound from a seated person side. A sound pickup device 1 includes a headrest 11 which is provided with an opening 29 on a seating surface 11a side, and has a recess 25 formed in the opening 29, and two or more sound pickup means, a first sound pickup means 31 and a second sound pickup means 32 are disposed in the recess 25 of the headrest 11, and the first sound pickup means 31 and the second sound pickup means 32 are disposed so that distances to the first sound pickup means 31 and the second sound pickup means 32 from a portion, closest to the seating surface 11a, of the opening 29 of the headrest 11 are different from each other.