Two-Dimensional Motor Based on Surface Acoustic Wave

Abstract

With the development of high precision processing, the miniaturization demand of motors with super-precision positioning and simple fabrication become an urgent problem. This paper illustrates a surface acoustic wave (SAW) motor for two-dimensional positioning. The SAW motor include a SAW stator and a slide. In order to realize the two-dimensional moving, four Interdigital Transducer (IDTs) are fabricated on the four directions of a 0.5-mm thick, 128°YX- LiNbO3substrate. Comparing the aluminum material, the copper material selected to be used as IDT in our experiment has many advantages. Each of the four copper IDTs has 10 straight finger pairs in a simple repeating pattern, the IDT aperture is 10mm and the pitch is 400μm. The SAW stator is fabricated by the lift-off process. The dimension of the device is 29mm (width) X29mm (length). The slide consists of three ruby balls with the diameter of 1mm and an plastic disc with the thickness of 0.5mm and the diameter is 8mm. With the four radio frequency driving sources, two-dimensional motion is possible. The maximum speed of the slide that was placed on the SAW propagating surface was 5mm/s when the applied driving power was 28W and the applied driving frequency was 9.6MHz. The experiments indicate the two-dimensional motor based on SAW would be applicable to miniature motor and improve the resolution.