17 November 2008 Light actuated piezoelectric speaker at resonant condition
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Proceedings Volume 7266, Optomechatronic Technologies 2008; 72660C (2008) https://doi.org/10.1117/12.813681
Event: International Symposium on Optomechatronic Technologies, 2008, San Diego, California, United States
Abstract
The concept of a light driven speaker was proposed as a new category of light driven actuator, and its feasibility was experimentally demonstrated. If a diaphragm of a speaker is made up of a light-driven actuator, sound would be produced upon irradiation of a modulated light. In this scheme, the light doubles as the signal and the energy source. With a conversion efficiency of 1 %, an audible sound is supposed to be generated from a 100 mW light source, therefore, energy-wise light actuated speaker should be possible. The limitation on the energy conversion efficiency of this scheme is discussed taking into account the energy loss due to the presence of a carrier wave that accompanies transmission. Unfortunately, a material that satisfies the requirements for this scheme is not found at present. Yet, since the purpose of this work is to show the feasibility of this concept and evaluate its possibility, it is an option to employ a combination of materials. In this preliminary study, we chose to combine a piezoelectric actuator and a solar cell with an appropriate interface for matching impedance. In the experiment, an 808 nm diode laser beam was modulated at audio frequency, and shined a solar cell. The audio signal was reproduced from the connected piezoelectric speaker as an audible sound. The maximum sound output of 3.1 mW was obtained. In a different scheme the maximum energy conversion efficiency of 4.4 % was obtained. These results show that the light actuated speaker is indeed feasible.
© (2008) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Hideki Okamura, Taki Yamamoto, Ryo Hamamura, "Light actuated piezoelectric speaker at resonant condition", Proc. SPIE 7266, Optomechatronic Technologies 2008, 72660C (17 November 2008); doi: 10.1117/12.813681; https://doi.org/10.1117/12.813681
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