SBIR Phase I:A New High-Strain Material for Medical Ultrasound Transducers

This Small Business Innovation Research Phase I project is aimed at engineering a high-strain piezoelectric material for use in medical ultrasound transducers. The proposed work entails investigations of the relaxor ferroelectric Pb(Yb0.5Nb0.5)O3-PbTiO3 (PYbN-PT). A major increase in the d31 and d33 piezoelectric coefficients can be realized by growing rhombohedral PYbN-PT crystals along the pseudocubic orientation. The objective is to attain the benefits of oriented single crystals, but to do so via the sol-gel thin film method. Our initial research in the area of relaxor ferroelectrics shows that PYbN-PT has significantly higher strain than lead zirconate titanate (PZT), the mainstay material of high performance transducers. In addition, the new film has many other desirable features of PZT. In Phase I, PYnB-PT will be developed and fully characterized for use in medical ultrasound. To be useful for medical ultrasound purposes, a PYbN-PT film thickness of at least 3-4 microns must be achieved. The proposed Phase I optimization study should be able to increase ultrasound system selectivity by more than one order of magnitude. The commercial application of this project is in the field of medical ultrasound imaging. The PYbN-PT film will be used to enhance the sensitivity of medical ultrasound images with cellular resolution. To achieve the necessary spatial resolution, the transducer must emit a high-frequency, broadband pulse. As the ultrasonic frequency increases, the attenuation of the diagnostic wave increases in human tissue and there is a need for more measurement sensitivity. The proposed investigation is particularly relevant to the development of low-cost imaging devices for ophthalmology, dermatology, and otolaryngology as well as for the intravascular assessment of coronary pathologies. For these applications, transducer sensitivity plays an important role in the differential diagnosis of disease.. Ultrasound is one of the most cost-effective imaging diagnostics, and its continued development in other medical disciplines satisfies an important social need.