TY - JOUR
T1 - Nonlinear spring effect of tense thin-film torsion bar combined with electrostatic driving
AU - Kundu, Subrata Kumar
AU - Ogawa, Shouhei
AU - Kumagai, Shinya
AU - Fujishima, Masayuki
AU - Hane, Kazuhiro
AU - Sasaki, Minoru
N1 - Funding Information:
This research was supported by the MEXT Grant-in-Aid for scientific research on challenging exploratory research ( 21656105 ) and the MEXT support programme for forming strategic research infrastructure ( S0801058 ). The facilities used include the Micro/Nano Machining Research and Education Center at Tohoku University.
PY - 2013
Y1 - 2013
N2 - Tense thin-film polycrystalline (poly-) Si torsion bars are advantageous in behaving as compliant springs against the twisting motion of electrostatically low-voltage-driven micromirrors. In this study, the nonlinear spring effect of the tense thin-film poly-Si torsion bar of a micromirror was characterised. The nonlinear spring effect of this torsion bar was explained theoretically, considering the bending and stretching effects in addition to the shear stress effect. The tensile stress induced in the thin-film poly-Si torsion bar is 300-400 MPa, and the bar maintains its compliance during the rotation of the mirror and increases its stiffness to suppress the pull-in instability. The torsion bar exhibits a large hard-spring effect with the bending of the film, observed as an increase of the ringing frequency. The spring constant was experimentally observed to increase by 6.25 times. The theoretical results agree well with the experimental results regarding the magnitude of the nonlinear spring constant.
AB - Tense thin-film polycrystalline (poly-) Si torsion bars are advantageous in behaving as compliant springs against the twisting motion of electrostatically low-voltage-driven micromirrors. In this study, the nonlinear spring effect of the tense thin-film poly-Si torsion bar of a micromirror was characterised. The nonlinear spring effect of this torsion bar was explained theoretically, considering the bending and stretching effects in addition to the shear stress effect. The tensile stress induced in the thin-film poly-Si torsion bar is 300-400 MPa, and the bar maintains its compliance during the rotation of the mirror and increases its stiffness to suppress the pull-in instability. The torsion bar exhibits a large hard-spring effect with the bending of the film, observed as an increase of the ringing frequency. The spring constant was experimentally observed to increase by 6.25 times. The theoretical results agree well with the experimental results regarding the magnitude of the nonlinear spring constant.
KW - Electrostatic actuation
KW - Hard-spring effect
KW - Nonlinear spring effect
KW - Thin-film torsion bar
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U2 - 10.1016/j.sna.2013.03.009
DO - 10.1016/j.sna.2013.03.009
M3 - Article
AN - SCOPUS:84876106065
SN - 0924-4247
VL - 195
SP - 83
EP - 89
JO - Sensors and Actuators A: Physical
JF - Sensors and Actuators A: Physical
ER -