Haake A, Dual J
Institute of Mechanical Systems, Center of Mechanics, Swiss Federal Institute of Technology Zurich (ETHZ), CH-8092 Zurich, Switzerland.
Ultrasonics. 2004 Apr;42(1-9):75-80. doi: 10.1016/j.ultras.2004.02.003.
A method for the controlled positioning of small particles in one or two dimensions by an ultrasound field excited by a surface wave is presented. Particles of a diameter between 10 and 100 microm placed on a surface can be concentrated at certain locations and moved over the surface. In other approaches it is possible to let the particle levitate freely in the fluid. However for the use of ultrasonic positioning in for example microassembling it is necessary to move particles over a surface as well as to let them levitate over the surface. Physical principle: A two- or three-dimensional ultrasound field is excited in a fluid filled gap between a rigid surface at the bottom and a vibrating surface of a solid at the top. The height of the gap varies between 0.1 and 2 mm. A one-dimensional sinusoidal vibration of the upper surface excites a two-dimensional ultrasound field in the fluid. Particles that are arbitrarily distributed on the lower surface will be concentrated in lines by the ultrasound field. First the calculation of the field of forces on particles in the fluid layer is presented. Then the dispersion relation of a vibrating plate which is in contact with a fluid on one side is derived. The technical setup will be introduced. Finally the experiments are shown and compared to the theoretical results.
提出了一种通过表面波激发的超声场在一维或二维上对小颗粒进行受控定位的方法。放置在表面上直径在10至100微米之间的颗粒可以聚集在特定位置并在表面上移动。在其他方法中，可以让颗粒在流体中自由悬浮。然而，例如在微组装中使用超声定位时，有必要让颗粒在表面上移动以及让它们在表面上方悬浮。物理原理：在底部的刚性表面与顶部的固体振动表面之间充满流体的间隙中激发二维或三维超声场。间隙高度在0.1至2毫米之间变化。上表面的一维正弦振动在流体中激发二维超声场。任意分布在下表面上的颗粒将被超声场集中成线。首先给出流体层中颗粒上力场的计算。然后推导一侧与流体接触的振动板的色散关系。将介绍技术装置。最后展示实验并与理论结果进行比较。
