Thermoacoustic sound generation from conductive indium tin oxide film

• Main Author: 吳伯音
• Other Authors: 蔡明善
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/13756624320014188929

碩士 === 國立嘉義大學 === 電子物理學系光電暨固態電子研究所 === 101 === The mechanism of thermalphone fabricated from conductive indium tin oxide film is studies in this thesis. When we applied an alternating current to the conductive film, due to Joule heating effects the temperature of the film would be change, at the surface of air and the film the heat would be transfer to the air molecules by thermal-mechanical coupling . The heat might let the molecules expansion and contraction to make a logic wave. Because this kind of sound emitter doesn’t have the problem of resonance frequency, it is smoother than the sound emitter we usually use which was made by piezo-transducers. in most studies have only focus on the wide frequency sound that sample can made, but no one had study on other physical properties of the devise. In this experiment, we made our thermalphone by ITO glass, which sound pressure level can reach up to 70db. We change the background temperature, shape, size and so on to find out how the sound spectrum would be changed. We found that as the frequency is changed, the spectrum will have some shock. When the background temperature is increased, the mean frequency peak would be moves higher frequency, and the sound pressure level is increased, and in the first side peak has a similar situation. We believe that this phenomenon is related with the sample modulation factor, which could be changed with frequency.This factor could affect the thermal diffusivity ratio of sample and air, and then change the magnitude of sound pressure level.