ELECTROSTATIC ACTUATOR WITH ELECTRET

In this paper, an electrostatic actuator with electret is proposed. El ectrets are the electrical equivalent of magnets. They are dielectric' s carrying a non equilibrium permanent space charge or polarization di stribution. This distribution can create either an external electric f ield or internal properties such as piezo or pyroelectricity. In the f irst case it is possible to make new types of electrostatic actuators by the external electric field. An electrostatic relay with electret i s fabricated to demonstrate the possibility of an electrostatic actuat or with electret. The size of relay is 5.2 mm x 11.5 mm. Its amature b eam is 50 mu m thick, 2.9 mm wide, 6.3 mm long, and acts as a moving e lectrode. Facing it, the stationary electrode is 20 mu m away from the moving electrode. On the stationary electrode, new type of electret m ade from SiO2 is deposited. We have succeeded in making the armature o perate at low applied voltage 20 V. On the same structure without elec tret, we need more than 120 V to make the same armature operation. We have also succeeded in making the armature latching.