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.
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.
