Goldberg R L, Smith S W, Brown L F
Department of Biomedical Engineering, Duke University, Durham, NC 27706.
Ultrason Imaging. 1992 Jul;14(3):234-48. doi: 10.1177/016173469201400302.
Phased-array images have been obtained in vivo with a steered copolymer array operating at 2.5 MHz. The array was fabricated using 28 microns copolymer film, lambda/4 resonant at 21 MHz, which was bonded to a glass ceramic backing with a thin film bond. The 32 array elements were created by laser ablation of the continuous gold electrode on one side of the film. The transducer was driven by 200 V shock excitation, and the received signal was processed by 32 custom IC preamplifiers that were mounted to the array connector. The amplifiers had a high input impedance compared to that of the array elements and their output impedance matched that of the coaxial cable that connected to the scanner. Because the copolymer transducer had a broad bandwidth, the spectrum of the pulse echo image was modified by the frequency dependent attenuation of tissue and the bandpass of the ultrasound scanner, resulting in a center frequency of 2.5 MHz. The performance of the copolymer array was compared to that of a 3 MHz, PZT array with similar dimensions. On the Duke phased-array scanner, the copolymer sensitivity was 28 dB less than that of PZT. The copolymer elements had a 6 dB pulse-echo angular response of 30 degrees, and the interelement cross-coupling was -35 dB. Phased-array images were made of the heart of a 25 year-old normal male.
使用工作频率为2.5MHz的相控阵共聚物阵列在体内获取了相控阵图像。该阵列采用28微米的共聚物薄膜制成，在21MHz时发生λ/4共振，通过薄膜键合与玻璃陶瓷背衬相连。通过对薄膜一侧的连续金电极进行激光烧蚀形成32个阵列元件。换能器由200V的冲击激励驱动，接收信号由安装在阵列连接器上的32个定制集成电路前置放大器进行处理。与阵列元件相比，这些放大器具有高输入阻抗，并且其输出阻抗与连接到扫描仪的同轴电缆的阻抗相匹配。由于共聚物换能器具有较宽的带宽，脉冲回波图像的频谱会因组织的频率依赖性衰减和超声扫描仪的带通而发生改变，从而得到中心频率为2.5MHz的图像。将共聚物阵列的性能与尺寸相似的3MHz的压电陶瓷（PZT）阵列的性能进行了比较。在杜克相控阵扫描仪上，共聚物的灵敏度比PZT低28dB。共聚物元件的脉冲回波角响应为30度，6dB，元件间交叉耦合为-35dB。对一名25岁正常男性的心脏进行了相控阵成像。
