| 摘要 |
<p>Piezoelectric films (20L, 20R) that expand and contract due to a noise emission drive signal applied thereto are disposed on a principal face of an exciter film (30). Frame members (50) are disposed at two opposite sides of the exciter film (30), and a diaphragm (40) is fastened to the exciter film (30) with the frame members (50) interposed therebetween. The diaphragm (40) is a flat plate, and is fastened to the exciter film (30) in a bowed profile that, in side view, gradually increases in distance away from the exciter film (30) toward the center region from the fastened ends. The exciter film (30) is thereby pulled outwardly from the fastened ends by bending stress. When a noise emission drive signal is applied to the piezoelectric films (20L, 20R) in this state, the exciter film (30) expands and contracts in response to expansion and contraction of the piezoelectric films (20L, 20R), and the diaphragm (40) vibrates.</p> |
