Open AccessA New Method for Airborne Sound Detection Using Total Internal Reflection and Its Application to Microphone
Author(s) -
Yasushi Suzuki,
Ken’iti Kido
Publication year - 2011
Publication title -
advances in optical technologies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.124
H-Index - 25
eISSN - 1687-6407
pISSN - 1687-6393
DOI - 10.1155/2011/547597
Subject(s) - microphone , acoustics , total internal reflection , sound intensity , reflection (computer programming) , sensitivity (control systems) , sound intensity probe , sound pressure , atmospheric pressure , sound (geography) , intensity (physics) , materials science , microphone array , optics , environmental science , physics , critical distance , computer science , sound power , meteorology , engineering , electronic engineering , programming language
A new method for detecting the sound pressure in air, which uses the total internal reflection at the curved interface between glass and air, is proposed, and its application to microphone is discussed. The critical angle for total reflection changes by the refractive index of air, which depends on the air density. The density changes by the sound pressure. Therefore, the sound pressure is measurable by detecting the intensity of the reflected light from the total reflection area. The sound pressure sensitivity of the proposed method is investigated theoretically and experimentally. Experimental results show that the microphone using the method is feasible though its sensitivity is low in the present stage. When the sensitivity is improved dramatically for practical use, the microphone becomes very sensitive to the surrounding conditions. A method to compensate the fluctuation of atmospheric pressure or temperature is presented
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