Aoyagi Takahiro, Nakazawa Marie, Tabaru Masaya, Nakamura Kentaro, Ueha Sadayuki
Tokyo Institute of Technology, Tokyo, Japan.
IEEE Trans Ultrason Ferroelectr Freq Control. 2009 Aug;56(8):1761-8. doi: 10.1109/TUFFC.2009.1241.
This paper presents the novel measurement method of the surface acoustic wave velocity by the variable-line- focus transducer using a polyurea piezoelectric ultrasonic transducer. First, a multiresonant polyurea thin-film ultrasonic transducer is fabricated by the vapor deposition polymerization process using 2 monomers. Second, the measurement system of surface acoustic wave velocity modified from the V(z) curve method is established. The system uses the fabricated polyurea thin film as a variable-line-focus transducer at the 30-MHz resonance frequency. The focal length is changed by varying the radius of curvature of the film transducer. To estimate the surface acoustic wave velocities from the measured data theoretically, the photographs of the transducer bent shapes are taken by using a digital microscope, and the bent transducer curvature is modeled by the 7th-order polynomial. To examine the performances of the variable-line-focus transducer, the surface acoustic wave velocities of an aluminum and a synthesized silica glass specimen have been measured. The measured surface acoustic velocities showed good agreement with the reference values.
本文介绍了一种利用聚脲压电超声换能器的可变线聚焦换能器测量表面声波速度的新方法。首先，采用气相沉积聚合法，使用两种单体制造了一种多谐振聚脲薄膜超声换能器。其次，建立了基于V(z)曲线法改进的表面声波速度测量系统。该系统使用制造的聚脲薄膜作为30 MHz共振频率下的可变线聚焦换能器。通过改变薄膜换能器的曲率半径来改变焦距。为了从理论上根据测量数据估计表面声波速度，使用数字显微镜拍摄换能器弯曲形状的照片，并通过七阶多项式对弯曲的换能器曲率进行建模。为了检验可变线聚焦换能器的性能，测量了铝和合成石英玻璃试样的表面声波速度。测量得到的表面声速与参考值吻合良好。
