A flexible PMUT device which can be applied on curved surfaces is presented. The oscillation behavior of the device under different curvatures (from ${\kappa } = 0$ to ${\kappa } =20\,\,\text{m}^{\mathbf {-1}}$ ), shows both modal frequency and vibration velocity shifts. The impact of bending of the device is discussed, in terms of stress given to the diaphragm. When the device is curved, additional stress is added to the diaphragm, opposite to the process-originated stress already presents on the device. An analytical model is introduced that explains the mechanical boundary condition of the diaphragm, which is altered when the device is laminated on a curved surface. The model can predict driving frequency and optimum design of the device according to the bending curvature. When the device is bent with a curvature of $\boldsymbol {\kappa } =20\,\,\text{m}^{\mathbf {-1}}$ , a driving frequency shift of around 10 kHz, which is 2% of the center frequency (503kHz) is predicted as well as measured, compared to device on the flat surface. The oscillation performance of the device increases by 37%, following the prediction of the model. [2020-0348]

中文翻译：

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基于聚合物材料和自适应频率驱动应力补偿的完全柔性 PMUT

提出了一种可应用于弯曲表面的灵活 PMUT 设备。器件在不同曲率下的振荡行为（从 ${\kappa } = 0$ 至 ${\kappa } =20\,\,\text{m}^{\mathbf {-1}}$ )，显示模态频率和振动速度的变化。根据施加到隔膜的应力，讨论了设备弯曲的影响。当设备弯曲时，额外的应力会添加到隔膜上，这与设备上已经存在的过程产生的应力相反。引入了一个分析模型，该模型解释了隔膜的机械边界条件，当设备层压在曲面上时，该边界条件会发生变化。该模型可以根据弯曲曲率预测器件的驱动频率和优化设计。当设备弯曲成曲率 $\boldsymbol {\kappa } =20\,\,\text{m}^{\mathbf {-1}}$ ，与平坦表面上的设备相比，预测和测量的驱动频移约为 10 kHz，即中心频率 (503kHz) 的 2%。根据模型的预测，设备的振荡性能提高了 37%。[2020-0348]