Optical Microphone Directionality Control via Beam Segmentation
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Solution Overview
Problem
Laser microphone devices face difficulties in localizing the direction of sound sources and distinguishing between multiple sound sources due to their inability to control directionality.
Innovation Solution
An optical microphone design that includes a light source, optical dividers, emitters, receivers, and detectors, which divide and couple light beams to detect interference patterns, allowing for signal processing to control sound pickup directionality and localize sound sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single light beam is used to detect sound, then the device structure is simple, but the directionality control capability is lost
Solution Approach 1:
The single light beam is segmented into multiple measurement light beams (first, second, third, and fourth measurement light beams) that are emitted from different positions and directions. Each beam detects sound from a specific spatial direction, enabling directionality control while maintaining relatively simple device structure through optical splitting rather than mechanical complexity
Solution Approach 2:
The invention transitions from a single-dimensional sound detection approach to a multi-dimensional approach by emitting light beams from multiple positions and directions. The multiple beams detect sound waves from different spatial dimensions, allowing the system to determine sound source direction and achieve directional control capability
2Measurement precision
If multiple measurement light beams are emitted from different positions, then sound source localization capability is improved, but the device complexity increases
Solution Approach 1:
The measurement light is segmented into multiple beams using optical dividers, with each beam directed from a different position toward the predetermined space. This segmentation allows sound source localization through comparative analysis of detection signals from each beam while avoiding the need for complex mechanical positioning systems
Solution Approach 2:
Multiple measurement light beams serve universal functions: each beam detects sound waves from different directions, and all beams are processed through the same optical detection and signal processing pathway. This multi-functionality approach achieves sound source localization without requiring entirely separate detection systems for each direction
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
Enables precise control over sound pickup directionality, allowing for effective detection of sounds from specific angles and improved localization of sound sources, even in the presence of multiple sound sources.
Implementation Method 1
a first optical divider that divides light emitted from the light source into reference light and measurement light; a second optical divider that divides the measurement light into N measurement light beams
Implementation Method 2
N optical detectors that receive N coupled light beams coupled by the N optical couplers, each of the N optical detectors detecting interference between a corresponding one of the N measurement light beams and a corresponding one of the N reference light beams
Implementation Method 3
N optical detectors that receive N coupled light beams coupled by the N optical couplers, each of the N optical detectors detecting interference between a corresponding one of the N measurement light beams and a corresponding one of the N reference light beams
Implementation Method 4
such laser microphone device uses laser light to detect changes in the refractive index of air caused by sound
Data Source
AI summary
An optical microphone includes: a light source; a first optical divider dividing light from the light source into reference light and measurement light; a second optical divider dividing the measurement light into N measurement light beams; a first emitter emitting the N measurement light beams from different positions toward a predetermined space; a first light receiver receiving the N measurement light beams having propagated through the space; a third optical divider dividing the reference light into N reference light beams; N optical couplers coupling the N measurement light beams with the N reference light beams on a one-to-one basis; N optical detectors receiving N coupled light beams and each detecting interference between the measurement light beam and the reference light beam in the corresponding coupled light beam; and a controller controlling directionality of sound pickup by performing signal processing on N detection signals from the N optical detectors.