| 摘要 |
PURPOSE:To flatten the frequency characteristic, to keep the speaker thin in size and to improve mass productivity without lowering the sound pressure level by supporting the outer periphery of the piezoelectric sounding body by a foamed body having an adhesive layer formed on the surface. CONSTITUTION:The piezoelectric sounding body may be a bimorph structure having piezoelectric plates adhered to both sides of the diaphragm 11a or a bonded structure of two piezoelectric plates in which the piezoelectric plate is used as the diaphragm 11a. The outer periphery of the piezoelectric sounding body 11 is secured by an adhesive layer 13 to the one inner surface of the ring-like foamed body 12 while the outer side of the one surface of the foamed body 12 secured to the sounding body is secured to a step 10b at the aperture end of a casing 10 by the adhesive layer 13. The outer periphery of the piezoelectric sounding body 11 is supported by the foamed body 12, while a cavity 14 is formed by a space defined by the piezoelectric sounding body 11 and the foamed body 12. The sound is produced through a sound emitting aperture 10a of the casing 10 based on the flexural vibrations of the sounding body 11. |
