DEVELOPMENT OF HIGH FREQUENCY(>30 MHZ) ARRAY TRANSDUCERS

多层陶瓷工艺将作为一种形成工作频率超过30 MHz的超声换能器的2-2 PZT-聚合物复合材料的方法进行研究。由PZT-聚合物复合材料制成的线性和相控阵目前被限制在10 MHz以下，这是因为需要加工成压电陶瓷的精细特征尺寸。目前切割锯技术仅限于15微米的切割宽度和20微米的立柱宽度。然而，通过使用带铸技术与印刷的逃逸材料相结合来形成缺口，可以形成尺寸为10微米的PZT波束宽度和5微米的缺口宽度。这将允许制造工作频率为30 MHz的线性和相控阵，提供电子波束控制和动态聚焦，用于皮肤科、眼科和血管内成像等应用中的高分辨率成像。对于第一阶段的工作，将通过使用多层技术制造单元件复合30 MHz换能器来证明其可行性。在第二阶段，这项技术将扩展到制造线性和相控阵，并将在临床试验中进行测试。建议的商业应用：高频相控阵超声换能器的潜在商业应用包括感兴趣的特征尺寸非常小或需要高分辨率以保证精度的医学成像。例如皮肤科(皮肤癌肿瘤的成像)、眼科和微创手术的血管内成像。

Multilayer ceramic processing will be investigated as a method of forming 2- 2 PZT-polymer composites for ultrasound transducers with operating frequencies over 30 MHz. The fabrication of linear and phased arrays made from piezoelectric PZT-polymer composites is currently limited to less than 10 MHz by the fine feature sizes that need to be machined into piezoelectric ceramic. Dicing saw technology is currently limited to cut widths (kerf) of 15 um and post widths of > 20 um. However, by using tape casting technology in combination with a printed fugitive material to form kerfs, dimensions < 10 um for PZT beam widths and < 5 um for kerf widths can be formed. This will allow the fabrication of linear and phased arrays with operating frequencies> 30 MHz providing electronic beam steering and dynamic focus for high resolution imaging in applications such as dermatology, ophthalmology, and intravascular imaging. For the Phase I effort feasibility will be demonstrated by fabricating a single element composite 30 MHz transducer using multilayer technology. In Phase II the technique will be expanded to the fabrication of linear and phased arrays which will be tested in clinical trials. PROPOSED COMMERCIAL APPLICATIONS: Potential commercial applications of high frequency, phased array ultrasound transducers include medical imaging where feature sizes of interest are very small or where high resolution is needed for accuracy. Examples include dermatology (imaging of skin cancer tumors), ophthalmology, and intravascular imaging for minimally invasive surgery.