| 摘要 |
PURPOSE:To prevent the sound pressure level from being lowered and to improve the directivity of sound, by taking the part of the resonant opening edge into floating between the opposing surfaces of the piezoelectric buzzer and the base mounted for the vibrating plate sticking with a piezoelectric element in the cylindrical echo unit with bottom plate. CONSTITUTION:The piezoelectric buzzer A is fixed with tightening by means of a pair of screws 7, 7 for the fitting pieces 6, 6 projected to the side of the opening edge of the resonator of cylindrical shape with bottom plate 3, and it is mounted on the base 5 such as printed board. The part between the opposing surfaces of the resonator opening edge 3a and the base 5 for the piezoelectric buzzer A is provided with the support material 8 bending the edge 3a into floating state. Thus, the gap b formed between the edge 3a and the base 5 becomes sound outlet and the sound formation having wide directivity can be made, and since the degree of absorption of the oscillation of the resonator 3 to the base 5 can be reduced with the floating state of the base 5 from the resonator 3a, the decrease in the sound pressure level can be avoided. |
