Transparent, Flexible, Ultrathin Sound Source Devices Using Indium Tin Oxide Films

Thermoacoustic effects were observed in 100-nm indium tin oxide (ITO) films. The sound emission from the ITO films was measured as a function of power, distance, and frequency. Significant flat and wide frequency responses occurred between 20 and 50 kHz. The sound pressure and efficiency were in good agreement with theoretical results. This indicates that a thermoacoustic effect exists in metal-oxide materials and that a large family of transparent electrode materials may exhibit similar properties. Using the ultrathin, transparent, and flexible characteristics, we showed promising applications of ITO sound source devices that were integrated with liquid crystal display screens. (C) 2011 American Institute of Physics. [doi:10.1063/1.3617462]