| 摘要 |
PURPOSE:To improve a sound pressure level at a low sound frequency by fixing a metal which is solderable with a metal of different kind from that of a metallic plate to an outer ridge of the metallic plate where piezoelectric elements are adhered so as to use a light metal as the material of the metallic plate. CONSTITUTION:The piezoelectric element 8 is adhered to the metallic plate 9 having a small specific gravity such as aluminum, aluminum alloy or titanium and the metal 10 of different type of material from the metallic plate 9, solderable such as brass or tin is fixed to the outer ridge of the metallic plate 9 by caulking or welding. A support plate 13 made of foamed plastic or rubber is bonded to the outer circumference of the piezoelectric element 7 constituted as above and the outer circumference of the support plate 13 is fixed by a frame 14 Leads 11, 12 are fitted by soldering to the piezoelectric element 8 and the different kind of the metal 10. Thus, it is possible to use the metallic plate 9 made of a light metal and the sound pressure level of a low sound frequency is improved. |
