Designing Thin Speaker Systems Using Single-walled Carbon Nanotubes

作者：Um Keehong^*; Kang Jeong Jin

来源：Information-An International Interdisciplinary Journal, 2012, 15(3): 1041-1052.

• film speaker
• CNT
• audible sound signals
• piezoelectric materials
• reverse piezoelectric effect
• SPL

Transparent, flexible, and thin film acoustic transducers can operate as acoustic actuators (speakers) and sensors (microphones) are developed in this study. A speaker is an audio system that produces sound in space through electronic and mechanical operations. It produces sound by transforming electric voltage signals into audible sound signals. Almost all speakers available with different volumes are three dimensional. These days, many mobile electronic devices such as mobile phones have become smaller, lighter, and thinner. A problem with this miniaturization, however, is that the volume of the speakers has also decreased. In contrast to conventional three dimensional speakers, there have been several attempts to develop two dimensional speakers using piezoelectric materials. The main parts have been piezoelectric films, conductive macromolecular coating materials, and electrodes. An improved material that has been used is that used indium tin oxide in place of conductive macromolecular coating materials. The developed transducer consists of a piezoelectric poly (vinylidene fluoride) (PVDF) two-dimensional thin film which is laminated with single-walled carbon nanotube (CNT) based transparent and flexible conductors. It is fabricated by CNT acid treatment and 5-layer assembly based surface modification of the PVDF substrates. The two dimensional flexible speaker was developed by applying carbon nanotube in order to replace indium tin oxide. The film speaker includes: a piezoelectric film oscillating by receiving a voltage corresponding to sound signal from a sound signal supply unit, a pair of carbon nanotube films formed on both sides of the piezo electric film, and a pair of electrodes connected to the pair of carbon nanotube films, receiving the voltage corresponding to the sound signal from the sound signal supply unit, and the voltage to the pair of carbon nanotube films. The speaker system we have designed shows outstanding advantages, such as flexibility, wide ranges of operating frequencies, and low values impedance values, and stability.

• 出版日期2012-3