Piezoelectrically driven translatory optical MEMS actuator with 7mm apertures and large displacements

Abstract

The design and manufacturing of a piezoelectrically driven translatory MEMS actuator is presented, which features a 7 mm aperture and four thin-film PZT actuators achieving large displacements. The actuator performs piston mode oscillation in resonance which can serve for Fourier Transform Infrared Spectroscopy (FTIR). Thereby vertical displacements in piston mode of up to ± 800 µm at 163 Hz and 25 V driving sinusoidal voltage has been achieved under ambient conditions. Due to the low frequencies and the low driving voltages only low power consumption is required. The effect of residual gas friction and internal friction on the piezo-driven MEMS actuator is analyzed by measuring Qvalues associated with the piston mode. Laser Doppler Vibrometry (LDV) was also used to detect and analyses the parasitic effects especially tilting which superimposes the vertical movement of the mirror. The deviation from the pure vertical piston mode was found to 1.3 µm along the x and 3 µm in the y-axis.

Modeling of biaxial gimbal-less MEMS scanning mirrors

“…Consequently, α and β are set according to equation (2) using the first two eigenfrequencies f 1,2 and the appropriate damping ratios ξ 1,2 = 1 2Q1,2 , that are calculated from experimentally measured amplitude decay curves. 1 Assuming f 1 = 160 Hz, f 2 = 365 Hz, Q 1 = 770 and Q 2 = 1200, the Rayleigh damping parameters become α = 1.17 s −1 and β = 1.39 · 10 −6 s. The quality factors resulting from the FEM modal analysis presented in Fig. 1(c) and Fig.…”

“…When actuated resonantly in its first eigenmode this mirror achieves vertical displacements up to ±800 µm at 25 V driving voltage under ambient conditions. For a more comprehensive description of the device including MEMS design and fabrication as well as a thorough experimental characterization the reader is referred to Quenzer et al 1 In order to simulate the dynamic behavior of the MEMS scanner as well as to obtain a mathematical model for analysis and control design, finite element modelling is applied using the commercial software COMSOL Multiphysics R . A 3D geometric representation of the micromirror is depicted in Fig.…”

Is Consumer Electronics Redesigning Our Cars?: Challenges of Integrated Technologies for Sensing, Computing, and Storage

“…A third, interesting but less pursued actuation scheme is based on piezoelectric actuators (Fig. 7, bottom) [29], which promise large torques at reasonable voltage levels. The main drawbacks are the complex kinematics required to amplify the modest deformations of piezoelectric materials, and the integration of piezoelectric materials into a MEMS technology.…”

Wafer-Level Vacuum-Packaged Translatory MEMS Actuator with Large Stroke for NIR-FT Spectrometers

“…Various MEMS concepts for optical path-length scanning have been reported, typically targeting an out-of-plane translation with large stroke required for the classical dual-beam Michelson interferometer FTS set-up, consisting of fixed and moving mirrors (here realized by an MOEMS) and an optical beam splitter. For large-stroke out-of-plane translation of the MEMS mirror, different actuation principles have been investigated so far: electrostatic [ 5 , 6 , 7 , 8 ], piezoelectric [ 9 , 10 , 11 ], magnetic [ 12 , 13 , 14 , 15 ], and electrothermal [ 16 , 17 , 18 , 19 , 20 , 21 , 22 ], typically using resonant operation for larger strokes, e.g., [ 7 , 8 , 11 ], but also using quasi-static actuation, e.g., [ 10 , 17 ]. Most of these different MOEMS actuation mechanisms suffer from limitations in spectral resolution due to parasitic effects of MEMS-based path-length modulation: first of all, mirror tilt [ 11 , 17 , 19 ], deformation of the mirror due to dynamically (owing to inertia) or statically (due to mirror suspension or optical coating) induced mechanical stress.…”