Electrostatic Actuator with Electret

Mitsuo ICHIYA  Fumihiro KASANO  Hiromi NISHIMURA  Jacques LEWINER  Didier PERINO  

IEICE TRANSACTIONS on Electronics   Vol.E78-C   No.2   pp.128-131
Publication Date: 1995/02/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Micromachines and Micro Electro Mechanical Systems)
electrostatic actuator,  electret,  silicon dioxide,  relay,  latching,  

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In this paper, an electrostatic actuator with electret is proposed. Electrets are the electrical equivalent of magnets. They are dielectric's carrying a non equilibrium permanent space charge or polarization distribution. This distribution can create either an external electric field or internal properties such as piezo or pyroelectricity. In the first case it is possible to make new types of electrostatic actuators by the external electric field. An electrostatic relay with electret is fabricated to demonstrate the possibility of an electrostatic actuator with electret. The size of relay is 5.2 mm11.5 mm. Its amature beam is 50 µm thick, 2.9 mm wide, 6.3 mm long, and acts as a moving electrode. Facing it, the stationary electrode is 20 µm away from the moving electrode. On the stationary electrode, new type of electret made from SiO2 is deposited. We have succeeded in making the armature operate at low applied voltage 20 V. On the same structure without electret, we need more than 120 V to make the same armature operation. We have also succeeded in making the armature latching.