Optical Microphone Acousto-Optic Medium Resonance Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional optical microphones face challenges in achieving flat frequency characteristics due to resonant frequencies dependent on the size of the acousto-optic medium section, leading to decreased sensitivity and inefficient acoustic wave detection.
Innovation Solution
An optical microphone design featuring an acousto-optic medium section with a pair of principal surfaces and lateral surfaces, where the restraint section prevents shape changes and allows principal surfaces to freely vibrate, enabling a flatter frequency characteristic by optimizing the optical path length variation caused by acoustic waves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the size of the acousto-optic medium section is reduced to achieve resonant frequency control, then the frequency characteristic can be adjusted, but the sensitivity and optical path length decrease
Solution Approach 1:
The patent divides the acousto-optic medium section into distinct functional regions: a first region with fixed boundary conditions (clamped lateral surface) and a second region with free boundary conditions (free lateral surface). This segmentation allows different portions of the medium to contribute differently to the overall performance, with the first region providing structural stability and the second region enhancing acoustic wave coupling and sensitivity without requiring overall size reduction.
Solution Approach 2:
The patent applies different boundary conditions to different regions of the acousto-optic medium section. The first region has clamped lateral surfaces that provide structural support and define resonant characteristics, while the second region has free lateral surfaces that maximize acoustic wave coupling. This local differentiation of properties allows the medium to simultaneously achieve frequency control and high sensitivity.
2Stability of the object's composition
If the acousto-optic medium section is constrained to prevent shape change, then structural stability is improved, but acoustic wave detection efficiency decreases
Solution Approach 1:
The patent segments the boundary conditions of the acousto-optic medium section into fixed and free regions. The first region has clamped lateral surfaces that provide structural stability and prevent unwanted shape changes, while the second region has free lateral surfaces that allow efficient acoustic wave coupling and detection. This segmentation resolves the contradiction between stability and detection efficiency.
Solution Approach 2:
Different portions of the acousto-optic medium section are given different mechanical properties through different boundary conditions. The clamped region provides local structural stability, while the free region provides local acoustic coupling efficiency. This local quality differentiation allows the entire structure to achieve both stability and detection efficiency simultaneously.
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 design achieves a flatter frequency characteristic and improved sensitivity without reducing the size of the acousto-optic medium section, enhancing the detection of acoustic waves by maintaining a long optical path length.
Implementation Method 1
In the acousto-optic medium section 203, propagation of the acoustic wave 205 causes a variation in refractive index. This refractive index variation is extracted by the laser Doppler vibrometer 204 as optical modulation, whereby the acoustic wave 205 is detected.
Implementation Method 2
a laser Doppler vibrometer 204... This refractive index variation is extracted by the laser Doppler vibrometer 204 as optical modulation
Data Source
AI summary
An optical microphone includes: an acousto-optic medium section having a pair of principal surfaces and at least one lateral surface provided therebetween; a restraint section which is in contact with the at least one lateral surface for preventing a shape change of the acousto-optic medium section; and a light emitting section for emitting a light wave so as to propagate through the acousto-optic medium section between the pair of principal surfaces. The pair of principal surfaces are in contact with an environmental fluid through which an acoustic wave to be detected is propagating and are capable of freely vibrating, and an optical path length variation of a light wave propagating through the acousto-optic medium section, which is caused by the acoustic wave that comes into the acousto-optic medium section from at least one of the pair of principal surfaces and propagates through the acousto-optic medium section, is detected.