Novel Micromachined Single Crystal Patterning for Wideband Dermatology Transducer

描述（由申请人提供）：拟议研究的目标是开发一种用于皮肤成像的极宽带，高频超声换能器。TRS提出通过在单个复合材料板内合并多个压电模式，为超声波换能器制造新颖的高频压电复合材料。光刻将用于定义微米级结构，化学蚀刻将用于微加工所需的换能器图案。该技术基于两个关键概念：单晶压电材料的深度反应离子蚀刻（DRIE），用于制作非常精细的换能器结构，以及随着长宽比（高/宽）的变化而发生的频率常数的巨大变化。通过非均匀图案化，在不同频率的板内存在多种模式。总带宽可以超过低频复合换能器和高频聚合物换能器。对于第一阶段，TRS将演示一个单元件，20-30 MHz的换向器，带宽接近150%。在第二阶段，将开发利用类似模式的复合线性阵列，以提高成像性能。该计划的成功完成将产生具有灵活性的换能器，可以提供高分辨率，提高穿透深度，减少扫描时间，并允许在小血管中提高多普勒性能。该技术将提高皮肤超声的性能，并有助于使超声在皮肤病学应用中更具临床相关性，如黑色素瘤和牛皮癣的表征，辐射诱导的纤维化和伤口愈合。

DESCRIPTION (provided by applicant): The goal of the proposed research is to develop an extremely broadband, high frequency ultrasound transducer for dermatologic imaging. TRS proposes to make novel, high frequency piezoelectric composites for ultrasound transducers by incorporating multiple piezoelectric modes within a single composite plate. Photolithography will be used to define micron-scale structures and chemical etching will be used to micro- machine the desired transducer pattern. The technology is based on two key concepts: deep reactive ion etching (DRIE) of single crystal piezoelectrics to make very fine scale transducer structures and the large change in frequency constant that occurs as the aspect ratio (height/width) changes. Through non-uniform patterning, multiple modes are present within the plate at different frequencies. The overall bandwidth can surpass that of lower frequency composite transducers and higher frequency polymer transducers. For Phase I TRS will demonstrate a single element, 20-30 MHz transducer with a bandwidth approaching 150%. In Phase II a composite linear array utilizing similar modes will be developed improved imaging performance. Successful completion of this program will produce transducers which have the flexibility to provide both high resolution as well as improved depth of penetration, decreasing scan time, and allowing for improved Doppler performance in small vessels. The technology will improve the performance of dermatologic ultrasound and help make ultrasound more clinically relevant for dermatology applications such as melanoma and psoriasis characterization, radiation-induced fibrosis and wound healing.