Dynamically Focused High Frequency Ultrasound Transducer

描述(申请人提供)：电活性聚合物将被研究为一种动态聚焦高频(&gt；30 MHz)、用于生物医学成像的单元件超声换能器的新方法。商业超声阵列技术一直被限制在20 MHz或更低，尽管目前的工作正在扩大工作范围，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50 MHz+范围。单元件换能器能够获得这些频率，然而，这些设备只有一个焦点。随着横向分辨率的增加，景深降低，迫使机械平移沿轴获得所需的完整图像。然而，通过使用电活性聚合物作为P(VDF-TrFE)压电聚合物的背板，空气作为衬垫，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面积高达100%，当它用作隔膜时，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30 MHz的单元件换能器，为眼科和皮肤科等应用中的高分辨率成像提供动态聚焦。对于第一阶段的工作，将通过使用电活性聚合物作为背板制造单个元件30 MHz换能器来证明其可行性。在第二阶段，这项技术将扩展到制造更高频率的设备(&gt；50 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.