Design And Research On 2D Array Transducer For Real-Time 3D Ultrasound Imaging

Compared with the traditional two-dimensional ultrasound imaging, real-time 3D ultrasound imaging technology has more potential clinical applications because it can provide more complete and objective information. As the heart of real-time 3D ultrasound imaging system, 2D array transducer determines the image quality. However, 2D array transducer is difficult to fabricate due to its massive numbers, small sizes and narrow pitch. Therefore, design and research on 2D array transducer is of great importance of both fundamental study and technical applications.For a N×N 2D array transducer, row-column addressing scheme can reduce the number of interconnects from N2 to 2N in comparison to fully sampled, which makes fabrication of 2D array simpler. The reported row-column addressing 2D array transducer with dual-layer design used one piezoelectric layer for transmit and another separate piezoelectric layer for receive. Despite this design contributed to reduce the fabrication complexity to some extent, it has some disadvantage in the dual-layer structure. To overcome this issue, based on single-layer piezoelectric material, a novel fabrication of row-column addressing 2D array transducer using high-precision mechanical cutting technology and new connecting method is proposed.In this thesis, we have designed and fabricated 3MHz and 8MHz 2D array transducers with 576 elements. For the fabrication of 3MHz 2D array transducer with element size of 200?m and kerf of 60?m, conductive backing material and full-cut method were used. Meanwhile, for 8MHz 2D array device building with the element size of 120?m and kerf of 47?m, nonconductive backing material and “not-full-cut” method were utilized. The COMSOL Multiphysic software was employed to simulate the vibration of the “not-full-cut” simple. The simulation result shows that its vibration mode is similar to full-cut when the kerf depth reaches 3/4 of the thickness of piezoelectric material. The measurement results demonstrate that each 2D array transducer has uniform electrical and acoustic properties.