An Ultrathin Flexible Loudspeaker Based on a Piezoelectric Microdome Array

Ultrathin, lightweight, high-performance, low- cost, and energy-efficient loudspeakers that can be deployed over a wide area have become increasingly attractive to both traditional audio systems and emerging applications such as active noise control and immersive entertainment. In this article, a thin-film loudspeaker is proposed based on an active piezoelectric layer embossed with an array of microscale domes. Actuation of these freestanding domes contributes to excellent sound generation by the loudspeaker, for example, 86 dB sound pressure level at 30-cm distance with 25-V (rms) excitation at 10 kHz, regardless of the rigid surface on which it is bonded. The acoustic performance is further tunable by designing the dome dimensions. The proposed loudspeaker also exhibits high bandwidth, which extends its prospects into the ultrasonic range. The loudspeaker weighs only 2 g, is 120
μ
m thick and can be manufactured at low cost. These advantages make the proposed loudspeaker a promising candidate for ubiquitous applications in existing and emerging industrial and commercial scenarios.