Micro-acousto-electro-mechanical systems (MAEMS). A systemic approach for a pervasive ultrasound

超声（US）成像系统提供了显著的优势，证明了为什么它们仍然是主要的临床成像程序（超过25%），以及超声在医疗领域之外的使用，在无损检测（NDT），工业（例如汽车）或消费应用（例如触觉接口）中。我们开发了一种新颖的，低成本的，基于聚合物的电容式微机械超声换能器（CMUT）阵列微加工技术，制造周期为几天，具有竞争力的换能器性能。目前的研究计划以结构化的方式将这项技术的好处推广到超声系统的各个架构层，以解决目前美国成像中的大多数挑战，并与超声无处不在的愿景保持一致。我们将该计划命名为“从MEMS到MAEMS”，以强调将已经普遍存在的MEMS（微机电系统）扩展到更广泛的MAEMS（微声电机械系统）领域。美国系统的几个主要挑战在不同的耦合水平上以组合和新颖的方式解决：技术开发，设备创新，电子接口，混合集成和组装，阵列信号处理和智能数据融合。低成本，甚至是一次性的美国传感器和系统可以通过低成本和绿色传感器微制造，结合大多数数字电子接口和混合装配解决方案（3D打印）来实现。在经典硅晶圆代工厂制造中不可能实现的个人定制，可以通过快速的微制造周期（1-2天），结合可编程数字电子和使用提取的降阶宏模型（rom）的快速并发设计和仿真周期。高性能成像将通过柔性基板上的大面积US阵列（保形US）获得，实现3D成像，多成像融合（例如x射线+ US或光声），依赖于所使用聚合物的光学和x射线透明度，以及基于数据融合的自适应波束形成，使用嵌入阵列的额外曲率/位置传感器的信息。通过polyCMUT阵列和电子器件的堆叠组件、数字比特流通道以及压缩感知来解决大量通道的互连/通信瓶颈。先进的信号处理应用将超分辨率成像算法与polyCMUT的电气可编程性（通过可变直流偏置电压）相结合。通过不同系统层之间的耦合，设计美国系统的集成路径为优化和创新提供了独特的机会。为了验证我们的方法的力量，主要针对两个主要应用：用于生物医学成像（心脏监测）的低成本保形美国系统和用于航空航天工业中CFRP板无损检测的大面积成像系统。

Ultrasound (US) imaging systems provide significant advantages that justify why they remain the dominant clinical imaging procedure (more than 25%), and the use of ultrasound outside the medical field, in non-destructive testing (NDT), industrial (e.g. automotive)  or consumer applications (e.g. for haptic interfaces). We have developed a novel, low-cost, polymer based microfabrication technology for Capacitive Micromachined Ultrasonic Transducer (CMUT) arrays, with a fabrication cycle of days, and competitive transducer performance. The present research program propagates the benefits of this technology, in a structured way, to the various architectural layers of an ultrasound system, to address most of the present challenges in US imaging and align with a vision where ultrasound will become ubiquitous. We entitle the program "from MEMS to MAEMS", to emphasize on the expansion of already pervasive MEMS (Micro-electro-mechanical systems) into a wider MAEMS (Micro-acousto-electro-mechanical systems) realm. Several major challenges in US systems are addressed in a combined  and novel manners, at different coupled levels: technology development, device innovations, electronic interface, hybrid integration and assembly, array signal processing and intelligent data fusion. Low-cost, even disposable US transducers and systems are achievable through low-cost and green transducers microfabrication, combined with mostly digital electronic interfaces and hybrid assembly solutions (3D printing). Individual-level customization, impossible in classic Si-foundries manufacturing, is possible through the rapid microfabrication cycle (1-2 days), combined with programmable digital electronics and a fast and concurrent design and simulation cycle using extracted reduced-order macromodels (ROMs). High performance imaging will be obtained through large area US arrays on flexible substrates (conformal US), enabling 3D imaging, multi-imaging fusion (e.g. X-Ray + US or opto-acoustic) that relies on the optical and X-Ray transparency of the polymer used, and adaptive beamforming based on data fusion,  using information from extra curvature/position sensors embedded in the array.  The interconnection/communication bottleneck for  a large number of channels are addressed through stacked assemblies of polyCMUT arrays and electronics, digital bitstreams channels, combined with compressive sensing. Advanced signal processing applications will combine super-resolution imaging algorithms with the electrical programmability of polyCMUT (through variable DC bias voltages). The integrated path in designing US systems presents unique opportunities for optimizations and novelties through coupling between different system layers. Two main applications are targeted, to validate the power of our approach: a low-cost conformal US system for biomedical imaging (heart monitoring) and a large area imaging system for NDT of CFRP plates used in the aerospace industry.