Wang Qi, Ruan Tao, Xu Qingda, Hu Zhiyong, Yang Bin, You Minmin, Lin Zude, Liu Jingquan
National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Shanghai Jiao Tong University, Shanghai 200240, China.
Department of Micro/Nano-Electronics, Collaborative Innovation Center of IFSA, Shanghai Jiao Tong University, Shanghai 200240, China.
Micromachines (Basel). 2023 Mar 22;14(3):702. doi: 10.3390/mi14030702.
To explore the versatility of speakers, a piezoelectric micro-electro-mechanical system (MEMS) speaker combining the function of a silent alarm is proposed, which mainly comprises a lead zirconate titanate (PZT) actuation layer and a rigid-flexible coupling supporting layer. Measurements performed on encapsulated prototypes mounted to an artificial ear simulator have revealed that, compared to a speaker with a rigid supporting layer, the sound pressure level (SPL) of the proposed piezoelectric MEMS speaker with a rigid-flexible coupling supporting layer is significantly higher and is especially higher by 4.1-20.1 dB in the frequency range from 20 Hz to 4.2 kHz, indicating that the rigid-flexible coupling supporting layer can improve the SPL significantly in low frequency. Moreover, the spectral distribution characteristic of its playback audio is similar to that of the commercial electromagnetic type. The device can also function as a silent alarm based on oral airflows in dangerous situations, as it performs well at recognizing words according to their unique voltage-signal characteristics, and can avoid the effects of external sound noise, body movement, long distance, and occlusion. This strategy provides inspiration for functional diversification of piezoelectric MEMS speakers.
为了探索扬声器的多功能性，提出了一种兼具静音报警功能的压电微机电系统（MEMS）扬声器，其主要由锆钛酸铅（PZT）驱动层和刚柔耦合支撑层组成。对安装在人工耳模拟器上的封装原型进行的测量表明，与具有刚性支撑层的扬声器相比，所提出的具有刚柔耦合支撑层的压电MEMS扬声器的声压级（SPL）显著更高，在20 Hz至4.2 kHz的频率范围内尤其高出4.1 - 20.1 dB，这表明刚柔耦合支撑层可以在低频显著提高声压级。此外，其播放音频的频谱分布特性与商用电磁型扬声器相似。该装置在危险情况下还可基于口腔气流用作静音报警器，因为它根据独特的电压信号特征在识别语音方面表现良好，并且可以避免外部声音噪声、身体运动、远距离和遮挡的影响。该策略为压电MEMS扬声器的功能多样化提供了灵感。
