An Electromagnetic Actuator in Lab-on-a-Chip Systems

A novel technique for the fabrication of electromagnetic micro actuators was proposed and a prototype was designed and fabricated in this study. The constituent parts of the designed actuator are comprised of the diaphragm, the micro coils, and the magnet. When an electrical current was applied to the micro coils, the magnetic force between the magnet and the coil is produced, causes the diaphragm to deflect and becomes the source of actuation. The fabrication process of the actuator combines Optical Lithography, Electron Beam Evaporation, and Electroplating. The structure of the actuating device uses PDMS as the vibrating diaphragm and electroplated copper as the coils. The diaphragm deflection can be regulated by varying the electrical current passed through the micro coil and hence the actuating effects can be controlled. The experimental results show that the maximum diaphragm deflection within elastic limits is 150 μm at an electrical current of 0.6 A for a micro coil of 100 μm line width. The micro electromagnetic actuator proposed in this study is easily fabricated and is readily integrated with Lab-on-a-Chip systems due to its planar structure.