| 摘要 |
PURPOSE:To establish the sound body not injuring the functions of alarm greatly due to normal change in environment, by interrupting the internal of the small sized audio unit from external air with the second vibrating plate. CONSTITUTION:As the oscillating plate of the sound body, it is constituted with the first vibrating plate 14 driven electrically and with the second vibrating plate 16 coupled with air spring via the air tight space approximately and directly in contact with external air. Further, by interrupting the air flow between the internal of the small sized audio device and external air with the second vibrating plate 16, the sound body not greatly injuring the function of alarm with the environmental change normally can be obtained. |
