Investigation on Electromagnetic Microactuator and Its Application in Micro-Electro-Mechanical System (MEMS)

In this paper, we presented the design, fabrication and testing of a novel bidirectional magnetic microactuator. The microactuator is composed of an integrated planar coil and a flexible polydimethyl siloxane (PDMS) diaphragm with embedded CoNiMnP-based permanent magnet arrays. There is a 7times7 array of magnets in a unit. The PDMS diaphragm is 2 mmtimes2 mmtimes40 mum and the magnet post is 50 mumtimes50 mumtimes20 mum. Computer simulation is applied to optimize the geometrical parameters. Electro-plating under external magnetic field is carried out to improve the magnetic properties of the electroplated magnet, including coercivity, remanence and magnetic energy and so on. The measured maximum coercivity, remanence and maximum magnetic energy are 2623 Oe(208.73 kA/m), 0.2 T(2000 G) 3 and 10.15 kJ/m with the magnet post respectively. Moreover,the deflection of the PDMS membrane is proportional to the exciting current. In a case of 0.35 A current, the maximum deflection of the membrane is 45 mum. Adjusting the electroplating mold results in the variation of the electroplated structure, thus the calibration of the microactuaor. Due to the biomedical compatibility and simplicity of the fabrication, the flexible membrane-based microactuator is potential to be used in MEMS (micro-electro-mechanical system) applications, such as micropump and optical switch.