Fabrication of Micromechanical Electromagnetic Relay

For the microminiaturization of electromagnetic relay and the enhance of its production efficiency, an micromechanical electromagnetic relay has been designed using micro electro mechanical systems(MEMS) fabrication process. The magnetic circuit of microrelay consists of the substrate magnetic circuit, a planar coil and a movable electrode. The relay takes "on" or "off depending on an exciting current. The relay size of about 5 mm ×5 mm × 0.4 mm is fabricated using the common micromachining technology like photoetching, sputtering, electroplating as well as etching sacrificial layer. Theoretical calculations are also carried out with respect to the electromagnetic forces yielded by the exciting coil with the use of magnetic circuit model. The optimum parameters concerning the coil and the vertical distance of the coil to the beam are attained with the simulation results. In addition, the primary testing results of the microrelay are given. The coil resistance is 300 Ω, the driving current of microrelay is no less than 50mA and the on-resistance of microrelay is 1.7Ω when it is on state.