High Performance Ultrasound Devise for Medical Imaging

描述（由申请人提供）：高频超声成像具有许多临床应用，因为其提高了图像分辨率。它作为检查眼前节、皮肤和血管内成像的临床工具正在获得认可。它的发展推动了超声成像技术的极限，提供了有关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具有厚度仅为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，将陶瓷研磨成非常薄的元件和切割非常小的元件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，我们在第一阶段已经证明，20-40 μ m厚的PZT薄膜可以通过一种新的溶胶-凝胶滴上工艺沉积，具有相对较高的介电常数（典型的er=780）。在后阶段I的研究中，厚PZT膜换能器设计使用PiezoCAD模型和厚PZT膜与一个匹配层制造。换能器的中心频率为40 MHz。-6dB处的带宽约为75%。在拟议的第二阶段研究和开发中，溶胶-凝胶落在PZT厚膜技术将进一步优化，以应用于高频医学成像。在器件设计中，声阻抗和电阻抗的匹配以及其它要求是一个难点。在第二阶段，我们将通过开发具有在1000至3000范围内可调介电常数的PZT膜来解决这个问题。设计并制作了频率为50-100 MHz的五单元原型线阵，采用不同衬底下的PZT厚膜。将调整厚度与宽度的纵横比以避免不期望的横向谐振。作为溶胶-凝胶前驱体和纳米粉体的供应商，Chemat将生产开发PZT细粉和PZT纳米复合厚膜前驱体，并销售溶胶-凝胶滴涂式PZT厚膜高频超声换能器。这项创新可能会影响高频医疗成像市场，因为将陶瓷研磨到几十微米是非常困难和耗时的。该项目的成功为高频单元件换能器和阵列的制造提供了一种具有放大能力和低成本的替代解决方案。

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.