誘導鈴における圧電型指向性スピーカの開発

抄録

Guiding chime is an acoustic welfare device for visually-impaired person, which is informed a direction of ticket gate of station by using guiding sound. However, direction inductivity of current product is insufficient, and it becomes a noise pollution to a station employee or user. Therefore, the purpose of this study is to design a directional speaker which is specialized to reproduce a guidance sound. In the experiment, thin flat panel type piezoelectric speakers using three vibrators was produced experimentally in order to design the sound directivity. The acoustic characteristics of speaker were evaluated by the frequency response measurements, and the sound directivities were evaluated by the radiated sound field visualization measurements. The results of this study shows that the prototype speaker could well reproduce 800Hz octave-band, which is important to recognize the guidance chime sound. And the sharp directivity of radiation sound was observed only at the direction of rectangular long-side of prototype speaker.