Presented in this paper is a bi-directional out-of-plane actuator which combines the merits of the electrostatic repulsive principle and the electrostatic attractive principle. By taking advantage of the electrostatic repulsive mode, the common “pull-in” instability can be lessened to enlarge the displacement, and by applying the electrostatic attractive mode, the out-of-plane displacement is further enlarged. The implications of changing the actuator’s physical dimensions are discussed, along with the two-layer polysilicon surface microfabrication process used to fabricate such an actuator. The static characteristics of the out-of-plane displacement versus the voltage of both modes are tested, and displacements of 1.4 μm and 0.63 μm are obtained at 130 V and 15 V, respectively. Therefore, a total stroke of 2.03 μm is achieved, more than 3 fold that of the electrostatic attractive mode, making this actuator useful in optical Micro-Electro-Mechanical Systems (MEMS) and Radio Frequency (RF) MEMS applications.
References
[1]
Horenstein, M.N.; Pappas, S.; Fishov, A.; Bifano, T.G. Electrostatic micromirrors for subaperturing in an adaptive optics system. J. Electrostat. 2002, 54, 321–332, doi:10.1016/S0304-3886(01)00159-0.
[2]
Hah, D.; Huang, S.-Y.; Tsai, J.-C.; Toshiyoshi, H.; Wu, M.C. Low-voltage, large-scan angle mems analog micromirror arrays with hidden vertical comb-drive actuators. J. Microelectromech. Syst. 2004, 13, 279–289, doi:10.1109/JMEMS.2004.825314.
[3]
Stewart, J.B.; Bifano, T.G.; Cornelissen, S.; Bierden, P.; Levine, B.M.; Cook, T. Design and development of a 331-segment tip–tilt–piston mirror array for space-based adaptive optics. Sens. Actuators A Phys. 2007, 138, 230–238, doi:10.1016/j.sna.2007.04.051.
[4]
Carr, E.; Olivier, S.; Solgaard, O. Large-stroke self-aligned vertical comb drive actuators for adaptive optics applications. Proc. SPIE 2006, 6133, doi:10.1117/12.656508.
[5]
Feng, Z.; Zhang, W.; Su, B.; Harsh, K.F.; Gupta, K.; Bright, V.; Lee, Y. Design and Modeling of RF MEMS Tunable Capacitors using Electro-thermal Actuators. In Proceedings of Microwave Symposium Digest, 1999 IEEE MTT-S International, Anaheim, CA, USA, 13–19 June 1999; pp. 1507–1510.
Bakri-Kassem, M.; Mansour, R.R. Two movable-plate nitride-loaded MEMS variable capacitor. IEEE T. Microw. Theory 2004, 52, 831–837, doi:10.1109/TMTT.2004.823598.
[8]
He, S.; Mrad, R.B. A Novel MEMS Tunable Capacitor. In Proceedings of the 2004 International Conference on MEMS, NANO and Smart Systems, Banff, Alberta, Canada, 25–27 August 2004; pp. 618–622.
[9]
Ji, C.-H.; Choi, M.; Kim, S.-C.; Lee, S.-H.; Kim, S.-H.; Yee, Y.; Bu, J.-U. An electrostatic scanning micromirror with diaphragm mirror plate and diamond-shaped reinforcement frame. J. Micromech. Microeng. 2006, 16, 1033, doi:10.1088/0960-1317/16/5/021.
[10]
Cugat, O.; Basrour, S.; Divoux, C.; Mounaix, P.; Reyne, G. Deformable magnetic mirror for adaptive optics: Technological aspects. Sens. Actuators A Phys. 2001, 89, 1–9, doi:10.1016/S0924-4247(00)00550-1.
[11]
Xu, X.-H.; Li, B.-Q.; Feng, Y.; Chu, J.-R. Design, fabrication and characterization of a bulk-pzt-actuated MEMS deformable mirror. J. Micromech. Microeng. 2007, 17, 2439, doi:10.1088/0960-1317/17/12/008.
[12]
Atre, A. Analysis of out-of-plane thermal microactuators. J. Micromech. Microeng. 2006, 16, 205, doi:10.1088/0960-1317/16/2/003.
[13]
Hardy, J.W. Adaptive Optics for Astronomical Telescopes; Oxford University Press: Oxford, UK, 1998.
[14]
Hu, F.; Yao, J.; Qiu, C.; Ren, H. A MEMS micromirror driven by electrostatic force. J. Electrost. 2010, 68, 237–242, doi:10.1016/j.elstat.2010.01.005.
[15]
Cornelissen, S.; Bierden, P.; Bifano, T. A 4096 element continuous facesheet mems deformable mirror for high-contrast imaging. J. Micro/Nanolith. MEMS MOEMS 2009, 8, doi:10.1117/1.3158067.
[16]
Wu, X.-t.; Brown, R.A.; Mathews, S.; Farmer, K. Extending the Travel Range of Electrostatic Micro-Mirrors Using Insulator Coated Electrodes. In Proceedings of 2000 IEEE/LEOS International Conference on Optical MEMS, Sheraton Kauai, HI, USA, 21–24 August 2000; pp. 151–152.
[17]
Helmbrecht, M.A.; He, M.; Juneau, T.; Hart, M.; Doble, N. Segmented MEMS deformable-mirror for wavefront correction. Proc. SPIE 2006, 6376, doi:10.1117/12.690809.
Tsai, J.-C.; Wu, M.C. Design, fabrication, and characterization of a high fill-factor, large scan-angle, two-axis scanner array driven by a leverage mechanism. J. Microelectromech. Syst. 2006, 15, 1209–1213, doi:10.1109/JMEMS.2006.880291.
[21]
Ren, H.; Tao, F.; Wang, W.; Yao, J. An out-of-plane electrostatic actuator based on the lever principle. J. Micromech. Microeng. 2011, 21, 045019, doi:10.1088/0960-1317/21/4/045019.
[22]
Ren, H.; Ni, Z.G.; Chen, J.M.; Gong, A.L.; Yao, J. A micro spatial light modulator based on leverage principle. Key Eng. Mat. 2011, 483, 137–142, doi:10.4028/www.scientific.net/KEM.483.137.
[23]
Lee, K.B.; Cho, Y.-H. Laterally driven electrostatic repulsive-force microactuators using asymmetric field distribution. J. Microelectromech. Syst. 2001, 10, 128–136, doi:10.1109/84.911101.
[24]
He, S.; Ben Mrad, R. Design, modeling, and demonstration of a MEMS repulsive-force out-of-plane electrostatic micro actuator. J. Microelectromech. Syst. 2008, 17, 532–547, doi:10.1109/JMEMS.2008.921710.
[25]
Yao, J.; Hu, F.; Cai, D.; Jiang, W. Design and analysis of repulsive electrostatic driven MEMS actuators. Proc. SPIE 2009, 7209, doi:10.1117/12.810791.
[26]
Ren, H.; Hu, F; Qiu, C.; Yao, J. Design and analysis of a novel out-of-plane actuator(in Chinese). J. Micronanoelectron. Technol. 2009, 46, 546–550.
[27]
IntelliSense. Available online: http://www.intellisense.com (accessed on 1 November 2013).
[28]
MUMPs. Available online: http://www.memscap.com/en_mumps.html (accessed on 1 November 2013).