Piezoelectric microphone via a DLP process

In nature sensors possess complex interlocking 3D structures and extremely localized material properties that allow processing of incredibly complex information in a small space. Acoustic sensor design is limited by fabrication processes, often MEMS based, where there is limited scope for fully 3D creations due to planer fabrication methods. Here we investigate the application of 3D printing via digital light processing (DLP) to integrate piezoelectric, conductive and structural polymer layers to create a complete electro-mechanical device. We demonstrate a working piezoelectric acoustic sensor, capable of sending electric signals that can be picked up by pre-amp circuitry fabricated using a commercially available 3D printer. We show that the 3D printing of mechanically sensitive membranes with thicknesses down to 35 $\mu m$ and tunable resonant frequencies is possible and further show it is possible to create a fully working electro-acoustic device by embedding 3D printed piezoelectric and conductive parts. Realizing this design opens up the possibility of generating truly 3D structured functional prints that may be used in bio-inspired design.

自然界中的传感器拥有复杂的互锁三维（3D）结构与高度局域化的材料特性，可在极小空间内处理极为复杂的信息。声学传感器的设计受限于制造工艺，此类工艺多基于微机电系统（MEMS），但平面制造工艺难以实现完全三维的结构创制。本研究探讨了基于数字光处理（DLP）的3D打印技术的应用场景，通过集成压电、导电与结构型聚合物层，以制备完整的机电一体化装置。本研究验证了一款可正常工作的压电式声学传感器，其能够输出电信号，该信号可被采用商用3D打印机制造的前置放大电路采集。研究证实，通过3D打印可制备厚度低至35微米（μm）的力学敏感膜，且其共振频率可调；进一步还证明，通过嵌入3D打印的压电与导电部件，能够制备出完整可用的电声装置。实现该设计方案，有望制备出真正具备三维结构的功能性打印件，可应用于仿生设计领域。