Development of high intensity and high frequency focused ultrasonic transducers with piezoelectric films.

2020 Fiscal Year Final Research Report

• Project/Area Number: 17K01427
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Medical systems
• Research Institution: Toin University of Yokohama
• Principal Investigator: Ishikawa Mutsuo 桐蔭横浜大学, 医用工学部, 講師 (90451864)
• Co-Investigator(Kenkyū-buntansha): 田原 麻梨江 東京工業大学, 科学技術創成研究院, 准教授 (60721884)
• Project Period (FY): 2017-04-01 – 2021-03-31
• Keywords: 超音波 / 高周波 / 非線形音響 / 圧電体 / 圧電結晶膜

Outline of Final Research Achievements

The KNbO3 films were deposited by hydrothermal method. It is known that the hydrothermal method is able to fabricate high quality piezoelectric films. In this study, we measured sound pressures and acoustic radiation pressures at resonant frequency with prototype high-frequency ultrasonic transducer using thickness mode of hydrothermal KNbO3 films.
The resonance frequency and radiated sound pressure of the prototype KNbO3 ultrasonic transducers of focusing type was measured by hydrophone. And, the radiated sound pressure has a linearity relationship between the applied voltages until 3 MPa at 10MHz. And the maximum pressure was approximately 4MPa or more. This value is very high intensity at high frequency and enough value for several high intensity ultrasonic applications with nonlinear acoustics.

Free Research Field

超音波、圧電体

Academic Significance and Societal Importance of the Research Achievements

試作した圧電結晶膜超音波トランスデューサを用いて、水中にて5MHz～20MHzにて、マイクロストリーミング、マイクロバブル、ナノバブルの発生、キャビテーションの発生、衝撃波の観察とそれによる音響化学反応の観察を行った。10MHzを超える周波数帯では上記のような非線形音響の観察例の報告は非常に少ないのが現状であるが、本研究により高周波での非線形音響現象用超音波トランスデューサの提案がなされた。