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This paper presents hysteresis property of tip-tilt-piston micromirror based on tilt-and-lateral shift-free piezoelectric unimorph actuator. The accuracy and the level of performance of piezoelectric actuator will be reduced for the reason of hysteresis behavior of piezoelectric device. To compensate the hysteresis behavior of the actuator, the properties should be researched and tested at first. The paper report the hysteresis behavior of micromirror with TLSF piezoelectric actuator under fixed frequency driving is stable with respect to the changes of the time and amplitude of driving voltage without considering the failure effect. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents the design, fabrication and characterization of a tip–tilt–piston (TTP) piezoelectric micromirror. A unique double S-shaped unimorph piezoelectric (dSUP) actuator design is employed. The dSUP actuator design can generate large vertical displacement. With four such actuators symmetrically located on the four sides of the mirror plate, both tip and tilt as well as piston motion can be realized. Lead zirconate titanate (PZT) is used due to its high piezoelectric coefficient and it is fabricated with a sol–gel method. The Zr/Ti ratio of the PZT material is 53/47. The dSUP actuators consist of Pt/Ti/PZT/Pt/Ti/SiO2 multilayers. The thickness of the PZT layer is 0.7μm. The 1.1mm×1.1mm mirror plate is backed by a 50μm-thick single-crystal silicon layer to ensure the flatness. Backside deep silicon etching and front-side isotropic silicon undercut are used to release the device. Experiments show that the resonant frequency of the tip–tilt scan modes is 3.5kHz. 27μm vertical displacement was observed under 5V DC driving of one pair of opposite actuator and the scan angle can achieve 9.65° under sine wave resonant driving at 2V amplitude on one pair of opposite actuator. [Copyright &y& Elsevier]

Abstract: This paper presents the design, fabrication and characterization of a piezoelectrically actuated high-fill-factor tip-tilt-piston (TTP) micromirror with small tilt and lateral shift during scanning. The piezoelectric material is a sol–gel lead zirconate titanate (PZT) thin film with a Zr/Ti ratio of 53/47. The small initial tilt and lateral-shift-free (LSF) of the mirror plate is achieved by a folded, three-segment piezoelectric unimorph actuator design. The piezoelectric unimorph actuation beams consist of Pt/Ti/PZT/Pt/Ti/SiO2 multilayers, which are released via undercutting the substrate silicon. The fabricated piezoelectric micromirror can be actuated about two rotational axes in the mirror plane and for translational vertical scan (piston actuation). The resonant frequencies of the piston and rotation modes are 316Hz and 582Hz, respectively. At their respective resonant frequencies, the maximum piston magnitude at resonant driving is 32μm, and the two-dimensional rotating scan ranges are about 5°, both measured at a 2Vpp sinusoidal driving voltage. [Copyright &y& Elsevier]