| 摘要 |
PURPOSE: To secure satisfactory sound quality without reducing the sound volume by preparing a vibration control part to a drive plate or a diaphragm to increase the amplitude and also to lower the resonance frequency for a piezoelectric sounding body which has the diaphragm supported by a casing that is bonded to the drive plate which is made of a piezoelectric material and has an electrode. CONSTITUTION: A piezoelectric sounding element 10 has a disk-like shape as a whole and includes a drive plate 14 which is bonded on a diaphragm 12. The mass of the plate 14 is larger than the mass defined on the basis of a case where the plate 14 has the same thickness as the diaphragm 12 and has a diameter ratio (plate 14 to diaphragm 12) of 0.7 or the thickness of the plate 14 is larger than that of the diaphragm 12. Thus, the plate 14 is bonded on the diaphragm 12 and the element 10 has a vibration control part. In such a constitution, the appropriate mass inertia is added to the vibration to lower the resonance frequency without reducing the sound volume and accordingly the satisfactory sound quality is secured.
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