Dynamically Focused High Frequency Ultrasound Transducer

描述（由申请人提供）：电活性聚合物将作为一种用于生物医学成像的动态聚焦高频（>30 MHz）单元件超声换能器的新手段进行研究。商业超声阵列技术被限制在20mhz或更少，尽管目前的工作正在增加工作范围，但实验阵列的频率仍然远远落后于实现足够分辨率所需的50mhz +范围。单元件换能器能够实现这些频率，但是，这些设备只有一个焦点。随着横向分辨率的增加，景深的减少，迫使机械平移沿轴，以实现所需的全图像。然而，通过使用电活性聚合物作为背板，并将空气作为P（VDF-TrFE）压电聚合物的衬底，将有可能动态改变单元件换能器的曲率，从而允许在不同深度聚焦。使用电压源，电活性聚合物可以改变高达100%的面积，当使用它作为隔膜时，它会根据电压的幅度影响不同的曲率。这将允许制造工作频率为> - 30mhz的单元件换能器，为眼科和皮肤病学等应用中的高分辨率成像提供动态聚焦。对于第一阶段的努力，将通过使用电活性聚合物作为背板制造单元件30 MHz换能器来证明可行性。在第二阶段，该技术将扩展到制造更高频率的设备（bbb50 MHz），并将测试生物组织实时成像的可行性。

DESCRIPTION (provided by applicant): Electroactive polymers will be investigated as a novel means to dynamically focus high frequency (>30 MHz), single element ultrasound transducers meant for biomedical imaging. Commercial ultrasound array technology has been limited to 20 MHz or less, and though current work is increasing the operating range, the frequency of experimental arrays still lags far behind the 50 MHz+ range necessary to achieve an adequate resolution. Single element transducers are capable of these frequencies, however, these devices only have one focus. As the lateral resolution is increased, the depth of field decreases, forcing mechanical translation along the axis to achieve the desired full image. However, by using electroactive polymers as a back plate, and air as a backing for P(VDF-TrFE) piezoelectric polymer, it will be possible to dynamically change the curvature of single element transducers, thus allowing for focusing at different depths. Using a voltage source, the electroactive polymers can change area by as much as 100%, and when using it as a diaphragm, it effects different curvatures depending upon the amplitude of the voltage. This will allow the fabrication of single element transducers with operating frequencies >30 MHz that provide dynamic focusing for high resolution imaging in applications such as ophthalmology and dermatology. For the Phase I effort feasibility will be demonstrated by fabricating a single element 30 MHz transducer using the electroactive polymer as a back plate. In Phase II, the technique will be expanded to fabrication of higher frequency devices (>50 MHz) and the feasibility for real-time imaging of biological tissues will be tested.