| 摘要 |
PURPOSE:To obtain sufficient sound pressure in a low frequency range and a flat response frequency characteristic in a wide frequency range, by compressing and inserting an elastic material into the diaphragm in a radius direction and pressing the diaphragm from its outer circumferential end surface to the center. CONSTITUTION:The elastic material such as foamed urethane rubber is sandwiched between the outer circumferential end surface of the diaphragm having a piezoelectric element 1 stuck to one surface and the inner circumferential surface of an annular supporting frame 3. The elastic material 4 is compressed in the radius direction of the diaphragm 2 and not compressed vertically. Therefore, the elastic material 4 presses the diaphragm 2 toward the center over the entire outer circumferential end surface. The disphragm 2 should by thick enough to resist the lateral pressing force, i.e. adequately 0.15-0.3mm. thick. Being applied with the lateral pressing force, the diaphragm is easily put in flectional vibration to obtain sufficiently high sound pressure in the low frequency range. |
