High Performance Ultrasound Devise for Medical Imaging

描述(申请人提供)：高频超声成像有许多临床应用，因为它提高了图像分辨率。作为一种检查眼前节、皮肤和血管内成像的临床工具，它正在被越来越多的人接受。它的发展推动了超声成像技术的发展，提供了关于活组织微观结构的诊断质量信息。高频成像的技术挑战之一是制造厚度只有几十微米的压电元件的换能器。在高频单元件换能器和阵列的制造中，将陶瓷压成很薄的元素和切成很小的元素是非常困难和耗时的。压电厚膜技术是一种低成本的替代解决方案。在NIH SBIR第一阶段的资金支持下，我们在第一阶段证明了通过一种新型的溶胶-凝胶滴加工艺可以沉积20-40微米厚的PZT薄膜，具有相对较高的介电常数(典型的Er=780)。在后一阶段的研究中，厚膜PZT换能器采用PiezoCAD模型进行设计，并由厚PZT膜与单层匹配层制成。换能器的中心频率为40 MHz。在-6分贝处的带宽约为75%。在提出的第二阶段研发中，Sol-Gel Drop-on PZT厚膜技术将进一步优化，以应用于高频医学成像。对于器件的设计，很难同时满足声阻抗和电阻抗等要求。在第二阶段，我们将通过开发介电常数在1000到3000范围内可调的PZT薄膜来解决这个问题。利用不同衬底上的PZT厚膜，设计并制作了频率为50~100 MHz的五元原型线阵。厚度与宽度的纵横比将被调整，以避免不必要的横向共振。作为Sol-Gel前驱体和纳米粉末的供应商，Chemat将开发PZT微粉和PZT纳米复合厚膜前驱体，并推出Sol-Gel滴入式厚膜高频超声换能器。这一创新可能会影响高频医学成像市场，因为将陶瓷研磨到几十微米是非常困难和耗时的。该项目的成功为具有放大能力和低成本的高频单元件换能器和阵列的制造提供了一种替代方案。

DESCRIPTION (provided by applicant): High frequency ultrasound imaging has many clinical applications because of its improved image resolution. It is gaining acceptance as a clinical tool for the examination of the anterior segment of the eye, skin and intravascular imaging. Its development has pushed the limits of ultrasonic imaging technology, giving diagnostic quality information about microscopic structures in living tissue. One of the technical challenges for high frequency imaging is the fabrication of transducers with piezoelectric elements of a thickness of only a few tens of micrometers. It is very difficult and time consuming to lap down the ceramic to very thin elements and to dice very small elements in the fabrication of high frequency single element transducers and arrays. Piezoelectric thick-film technology is an alternative solution with a low cost. With NIH SBIR Phase I funding support, we have proven in Phase I that 20-40 urn thick PZT film can be deposited via a novel sol-gel drop-on process, with relatively high dielectric constant (typical er=780). In the post Phase I research, thick PZT film transducers were designed using a PiezoCAD model and fabricated from thick PZT film with one matching layer. The central frequency of the transducer was 40 MHz. The bandwidth at -6 dB was approximately 75%. In proposed Phase II research and development, the sol-gel drop-on PZT thick film technology will be further optimized towards application in high frequency medical imaging. For device design, it is difficult to match both acoustic impedance and electric impedance and other requirement. During Phase II, we will address this problem by developing PZT film with adjustable dielectric constant in the range of 1000 to 3000. Five-element prototype linear arrays with frequency of 50-100 MHz will be designed and fabricated using PZT thick films under different substrates. The thickness to width aspect ratio will be adjusted to avoid undesirable lateral resonance. As a supplier for sol-gel precursors and nano powders, Chemat will production develop PZT fine powder and PZT nanocomposite thick film precursor and market sol-gel drop-on thick PZT film high frequency ultrasonic transducer. This innovation may impact high frequency medical imaging market, since lapping down ceramics to a few tens micrometers is very difficult and time consuming. Success of this project provides an alternative solution for fabrication of high frequency single element transducers and array with scale-up capability and low cost.