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Book ChapterDOI

Modeling of Electrothermal Microactuator

TL;DR: In this article, the authors presented the modeling of electrothermally actuated bimorph actuator for out-of-plane actuation application, which was optimized for higher displacement applications.
Abstract: This paper presents the modeling of electrothermally actuated bimorph actuator for out-of-plane actuation application. Al-Si bimorph was optimized for higher displacement applications. Temperature distribution analysis of the Al-Si bimorph combination was chosen due to their larger displacement range. The modeling of Al-Si was performed with FEM and analytical analysis. Temperature distribution across the bimorph actuator with respect to length and applied voltage was optimized using FEM, lumped, and analytical analysis. The maximum temperature across Al-Si bimorph was achieved around 106 °C without convection and 85 °C with convection.
Citations
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Book ChapterDOI
12 Sep 2022
TL;DR: In this paper , a reliability analysis of thermally actuated MEMS micromirror devices was presented, and the reliability distribution function and lifetime of the MEMS micro-irror were analyzed.
Abstract: This paper presents a reliability analysis of thermally actuated MEMS micromirror devices. The various factors affecting the reliability of the MEMS micromirror device were analyzed and discussed. The reliability distribution function and lifetime of the MEMS micromirror were analyzed. The series and parallel model reliability model for MEMS micromirror were reported. The p-out-of-n redundancy model was considered to increase reliability for the MEMS micromirror device. This model gives more redundancy to it, and the failure of one or more devices does not affect the system performance.
References
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Journal ArticleDOI
01 Dec 1998
TL;DR: Inertial sensors have seen a steady improvement in their performance, and today, microaccelerometers can resolve accelerations in the micro-g range, while the performance of gyroscopes has improved by a factor of 10/spl times/ every two years during the past eight years.
Abstract: This paper presents a review of silicon micromachined accelerometers and gyroscopes. Following a brief introduction to their operating principles and specifications, various device structures, fabrication, technologies, device designs, packaging, and interface electronics issues, along with the present status in the commercialization of micromachined inertial sensors, are discussed. Inertial sensors have seen a steady improvement in their performance, and today, microaccelerometers can resolve accelerations in the micro-g range, while the performance of gyroscopes has improved by a factor of 10/spl times/ every two years during the past eight years. This impressive drive to higher performance, lower cost, greater functionality, higher levels of integration, and higher volume will continue as new fabrication, circuit, and packaging techniques are developed to meet the ever increasing demand for inertial sensors.

1,816 citations

Journal ArticleDOI
TL;DR: In this article, a nonlinear model of electrically actuated microbeams accounting for the electrostatic forcing of the air gap capacitor, the restoring force of the microbeam and the axial load applied to the micro-beam is presented.
Abstract: We present a nonlinear model of electrically actuated microbeams accounting for the electrostatic forcing of the air gap capacitor, the restoring force of the microbeam and the axial load applied to the microbeam The boundary-value problem describing the static deflection of the microbeam under the electrostatic force due to a dc polarization voltage is solved numerically The eigenvalue problem describing the vibration of the microbeam around its statically deflected position is solved numerically for the natural frequencies and mode shapes Comparison of results generated by our model to the experimental results shows excellent agreement, thus verifying the model Our results show that failure to account for mid-plane stretching in the microbeam restoring force leads to an underestimation of the stability limits It also shows that the ratio of the width of the air gap to the microbeam thickness can be tuned to extend the domain of the linear relationship between the dc polarization voltage and the fundamental natural frequency This fact and the ability of the nonlinear model to accurately predict the natural frequencies for any dc polarization voltage allow designers to use a wider range of dc polarization voltages in resonators

473 citations

Journal ArticleDOI
TL;DR: In this article, the authors demonstrate a fully monolithic silicon optical scanner with large static optical beam deflection, which can be used for both one-and two-axis rotation and pistoning of a micromirror.
Abstract: In this paper, fully monolithic silicon optical scanners are demonstrated with large static optical beam deflection. The main advantage of the scanners is their high speed of operation for both axes: namely, the actuators allow static two-axis rotation in addition to pistoning of a micromirror without the need for gimbals or specialized isolation technologies. The basic device is actuated by four orthogonally arranged vertical comb-drive rotators etched in the device layer of an silicon-on-insulator wafer, which are coupled by mechanical linkages and mechanical rotation transformers to a central micromirror. The transformers allow larger static rotations of the micromirror from the comb-drive stroke limited rotation of the actuators, with a magnification of up to 3/spl times/ angle demonstrated. A variety of one-axis and two-axis devices have been successfully fabricated and tested, in all cases with 600-/spl mu/m-diameter micromirrors. One-axis micromirrors achieve static optical beam deflections of >20/spl deg/ and peak-to-peak resonant scanning of >50/spl deg/ in one example at a resonant frequency of 4447 Hz. Many two-axis devices utilizing four rotators were tested, and exhibit >18/spl deg/ of static optical deflection at <150 V, while their lowest resonant frequencies are above 4.5 kHz for both axes. A device which utilizes only three bidirectional rotators for tip-tilt-piston actuation achieves -10/spl deg/ to 10/spl deg/ of optical deflection in all axes, and exhibits minimum resonant frequencies of 4096 and 1890 Hz for rotation and pistoning, respectively. Finally, we discuss the preliminary results in scaling tip-tilt-piston devices down to 0.4 /spl times/ 0.4 mm on a side for high fill-factor optical phased arrays. These array elements include bonded low-inertia micromirrors which fully cover the actuators to achieve high fill-factor.

211 citations

Journal ArticleDOI
TL;DR: In this article, a comprehensive thermal model for an electro-thermal-compliant (ETC) microactuator is presented, which accounts for all modes of heat dissipation and the temperature dependence of thermophysical and heat transfer properties.
Abstract: A comprehensive thermal model for an electro-thermal-compliant (ETC) microactuator is presented in this paper. The model accounts for all modes of heat dissipation and the temperature dependence of thermophysical and heat transfer properties. The thermal modelling technique underlying the microactuator model is general and can be used for the virtual testing of any ETC device over a wide range of temperatures (300-1500 K). The influence of physical size and thermal boundary conditions at the anchors, where the device is connected to the substrate, on the behaviour of an ETC microactuator is studied by finite element simulations based on the comprehensive thermal model. Simulations show that the performance ratio of the microactuator increased by two orders of magnitude when the characteristic length of the device was increased by one order of magnitude from 0.22 to 2.2 mm. Restricting heat loss to the substrate via the device anchors increased the actuator stroke by 66% and its energy efficiency by 400%, on average, over the temperature range of 300-1500 K. An important observation made is that the size of the device and thermal boundary conditions at the device anchor primarily control the stroke, operating temperature and performance ratio of the microactuator for a given electrical conductivity.

196 citations

Journal ArticleDOI
TL;DR: In this article, the authors highlight another advantage of thermal actuation, viz. the ease with which it can be utilized to achieve a novel embedded electro-thermal-compliant (ETC) actuation for MEMS.
Abstract: At the micro-scale, thermal actuation provides larger forces compared to the widely-used electrostatic actuation. In this paper, we highlight another advantage of thermal actuation, viz. the ease with which it can be utilized to achieve a novel embedded electro-thermal-compliant (ETC) actuation for MEMS. The principle of ETC actuation is based on the selective non-uniform Joule heating and the accompanying constrained thermal expansion. It is shown here that appropriate topology and shape of the structures give rise to many types of actuators and devices. Additionally, selective doping of silicon ETC devices is used to enhance the non-uniform heating and thus the deformation. A number of novel ETC building blocks and devices are described, and their analysis and design issues are discussed. The devices were microfabricated using MCNC’s MUMPs foundry process as well as a bulk-micromachining process called PennSOIL (Penn silicon-on-insulator layer). The designs are validated with the simulations and the experimental observations. The experimental measurements are quantitatively compared with the theoretical predictions for a novel ETC microactuator with selective doping.

152 citations