| 摘要 |
PURPOSE:To improve sound pressure in a ringing frequency band by perforating auxiliary sound discharging holes around a main sound discharging hole formed on the center part of a resonator. CONSTITUTION:A diaphragm 5 having a piezoelectric element 6 is stored in a resonator 1. The main sound discharging hole 3 penetrated into the resonator 1 is formed on the center part of the upper face and the auxiliary sound discharging holes 2, 2... whose diameters are smaller than that of the hole 3 are perforated so as to surround the hole 3. Namely, only the auxiliary sound discharging holes 2, 2... are formed without changing shapes or sizes of the resonator 1, the diaphragm 5 and the piezoelectric element 6. As compared with a conventional device, the output sound pressure in the 0.8 to 1.4kHz ringing frequency band is improved as the result of ringing tests. Thus, high sound volume can be obtained. |
