利用声表面波实现液体的二维驱动(英文)

报道了利用声表面波实现水滴二维驱动的实验.在127.8° Y切X向传播的铌酸锂衬底上制作了4个叉指换能器.每个叉指换能器由10对电极构成,其叉指周期为400 μm,宽度为100 μm,孔径为12 mm,整个器件的尺寸为26 mm×26 mm×0.45 mm.由于铌酸锂晶体的各向异性,叉指换能器沿Y、X方向的谐振频率不同,分别为9.3 MHz 和9.6 MHz.基于铜材料相对于铝材料的优点,选用了铜材料并采用剥离工艺制作了电极,得到了优化的工艺参数.最后,用了超长时间超声波辅助方法彻底去除残胶,实现了对水滴的二维驱动,输入功率为9 W,液滴运动的平均速率为5 mm/s.利用ANSYS软件分析了声表面波在铌酸锂衬底内的传播,内部振动的模拟结果与理论分析一致.实验表明,利用声表面波实现液体的二维驱动是可行的,该液体驱动原型可用于片上系统和μ-TAS.

Two-dimensional actuation of liquid using surface acoustic wave

This paper reports the two-dimensional actuation of a water drop by using a Surface Acoustic Wave(SAW). Four Interdigital Transducers (IDTs) is fabricated on a 127.8° rotated Y-cut X-propagation LiNbO3 substrate. Each IDT is composed of 10 strip electrode pairs,which is 400 μm in pitch, 100 μm in electrode strip width and 12 mm in aperture. The overall size of the device is 26 mm×26 mm×0.45 mm. Due to the anisotropy of LiNbO3 crystal, the resonance frequencies of IDTs are in 9.3 MHz along Y axis and 9.6 MHz along X axis, respectively. Being superior in characteristics to alunimium, copper is used as the electrode material in fabrication process and the Lift-off process is adopted to fabricate electrodes,so that optimum process parameters are finally obtained. An ultra-long-time ultrasonic assistance is used to get rid of residues completely, finally,a two-dimensional actuation of the water drop is observed,which shows the input power is 9 W and the average speed is drop movement is 5 mm/s.The propagation of SAW in LiNbO3 substrate is simulated with ANSYS, simulation result agrees well with the calculation of theoretical vibration amplitude in LiNbO3. This research demonstrates that the two-dimensional acuation of a liquid drop by using the SAW is feasible. This prototype of liquid actuation is promising in lab-on-chip and μ-TAS applications