压电MEMS扬声器的设计与优化

Design and Optimization of Piezoelectric MEMS Speakers

为了提高压电微机电系统(MEMS)扬声器的声压级,该文提出了一种新型的扬声器振膜结构,该结构由4个相同的扇环驱动单元和中间圆形质量块组成,并在上表面覆有一层柔性材料,形成刚性-柔性耦合封闭振动膜。优化该结构中圆形质量块半径r_(2)和相邻扇环的相邻边夹角θ等参数。结果表明,当θ=50°,r_(2)=700μm时,声压级最大。在保证振膜面积相同和谐振频率基本一致的情况下,与优化后的固支圆形多层振膜相比,该文所提出的新型结构声压级高5 dB。

In order to improve the sound pressure level(SPL)of piezoelectric micro-electro-mechanical systems(MEMS)speakers,a novel speaker diaphragm structure is proposed in this paper.The structure consists of four identical fan-ring driving units and a circular mass block in the middle,and the upper surface is covered with a layer of flexible material,forming a rigid-flexible-coupling sealed vibration membrane.The parameters such as radius r_(2) of the circular mass block and angleθof adjacent fan rings were optimized.It was found that the maximum SPL was obtained whenθ=50°and r_(2)=700μm.The sound pressure level of the novel structure proposed in this paper is 5 dB higher than that of the optimized clamped circular multilayer diaphragm under the condition that the diaphragm area is the same and the resonant frequency is basically the same.