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Micromachines
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MEMS Mirrors
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MEMS Mirrors

A special issue of Micromachines (ISSN 2072-666X).

Deadline for manuscript submissions: closed (31 March 2017) | Viewed by 109860

Printed Edition Available!
A printed edition of this Special Issue is available here.

Special Issue Editor

Prof. Dr. Huikai Xie

E-Mail Website
Guest Editor
School of Information and Electronics, Beijing Institute of Technology, Beijing 100081, China
Interests: MEMS; CMOS-MEMS sensors; micromirrors; microactuators; piezoelectric MEMS microspeakers; pMUTs; photoacoustic microscopy; optical endomicroscopy
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

MEMS mirrors can steer, modulate and switch light, as well as control the wavefront for focusing or phase modulation. MEMS mirrors have found enormous commercial success in projectors, displays and fiberoptic communications. Micro-spectrometers based on MEMS mirrors are starting to appear in the consumer market. There are also many breakthroughs in applying MEMS mirrors for endoscopic imaging. Equally excitingly, a new wave of opportunities for MEMS mirrors is coming up, for example, micro-LiDAR for autonomous driving and robotics, optical cross connect (OXC) for cloud data centers, and optical scanners for virtual reality/augumented reality, just to name a few. Of course, there are a number of big challenges that researchers and engineers must overcome to fully utiltize MEMS mirrors’ potential: modeling and control are inherently complex due to the multiphysics, multi-DOF and nonlinear nature of the microactuators for MEMS mirrors; reliability is always a huge hurdle for commercilization; and the tradeoffs among the speed, aperture, and scan range are often overwhelming. Accordingly, this Special Issue seeks to showcase research papers, short communications, and review articles that focus on: (1) novel designs, fabrication, control, and modeling of MEMS mirrors based on all kinds of actuation mechanisms; and (2) new developments of applying MEMS mirrors of any kind in consumer electronics, optical communications, industry, medicine, agriculture, space, or defense.

Prof. Dr. Huikai Xie
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Micromachines is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • MEMS mirrors: electrostatic, electromagnetic, electrothermal, piezoelectric, etc.
  • Deformable micromirrors
  • MEMS mirror arrays
  • MEMS mirror modeling
  • MEMS mirror control
  • MEMS mirror applications:
    • Optical communications: OXC, WSS, VOA, LiFi
    • Optical imaging
    • LiDAR
    • Spectrometers
    • Displays
    • Space
    • Other

Published Papers (16 papers)

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Editorial

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3 pages, 167 KiB  
Editorial
Editorial for the Special Issue on MEMS Mirrors
by Huikai Xie
Micromachines 2018, 9(3), 99; https://doi.org/10.3390/mi9030099 - 27 Feb 2018
Cited by 4 | Viewed by 3858
Abstract
MEMS mirrors can steer, modulate, and switch light, as well as control the wavefront for focusing or phase modulation.[...] Full article
(This article belongs to the Special Issue MEMS Mirrors)

Research

Jump to: Editorial

1082 KiB  
Article
An Enhanced Robust Control Algorithm Based on CNF and ISM for the MEMS Micromirror against Input Saturation and Disturbance
by Jiazheng Tan, Weijie Sun and John T. W. Yeow
Micromachines 2017, 8(11), 326; https://doi.org/10.3390/mi8110326 - 03 Nov 2017
Cited by 13 | Viewed by 3834
Abstract
Input saturation is a widespread phenomenon in the field of instrumentation, and is harmful to performance and robustness. In this paper, a control design framework based on composite nonlinear feedback (CNF) and integral sliding mode (ISM) technique is proposed for a MEMS micromirror [...] Read more.
Input saturation is a widespread phenomenon in the field of instrumentation, and is harmful to performance and robustness. In this paper, a control design framework based on composite nonlinear feedback (CNF) and integral sliding mode (ISM) technique is proposed for a MEMS micromirror to improve its performance under input saturation. To make the framework more effective, some essential improvements are supplied. With the application of the proposed design framework, the micromirror under input saturation and time-varying disturbances can achieve precise positioning with satisfactory transient performance compared with the open-loop performance. Full article
(This article belongs to the Special Issue MEMS Mirrors)
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3508 KiB  
Article
Fabrication of Micro-Optics Elements with Arbitrary Surface Profiles Based on One-Step Maskless Grayscale Lithography
by Qinyuan Deng, Yong Yang, Hongtao Gao, Yi Zhou, Yu He and Song Hu
Micromachines 2017, 8(10), 314; https://doi.org/10.3390/mi8100314 - 23 Oct 2017
Cited by 35 | Viewed by 11631
Abstract
A maskless lithography method to realize the rapid and cost-effective fabrication of micro-optics elements with arbitrary surface profiles is reported. A digital micro-mirror device (DMD) is applied to flexibly modulate that the exposure dose according to the surface profile of the structure to [...] Read more.
A maskless lithography method to realize the rapid and cost-effective fabrication of micro-optics elements with arbitrary surface profiles is reported. A digital micro-mirror device (DMD) is applied to flexibly modulate that the exposure dose according to the surface profile of the structure to be fabricated. Due to the fact that not only the relationship between the grayscale levels of the DMD and the exposure dose on the surface of the photoresist, but also the dependence of the exposure depth on the exposure dose, deviate from a linear relationship arising from the DMD and photoresist, respectively, and cannot be systemically eliminated, complicated fabrication art and large fabrication error will results. A method of compensating the two nonlinear effects is proposed that can be used to accurately design the digital grayscale mask and ensure a precise control of the surface profile of the structure to be fabricated. To testify to the reliability of this approach, several typical array elements with a spherical surface, aspherical surface, and conic surface have been fabricated and tested. The root-mean-square (RMS) between the test and design value of the surface height is about 0.1 μm. The proposed method of compensating the nonlinear effect in maskless lithography can be directly used to control the grayscale levels of the DMD for fabricating the structure with an arbitrary surface profile. Full article
(This article belongs to the Special Issue MEMS Mirrors)
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4672 KiB  
Article
Modelling and Experimental Verification of Step Response Overshoot Removal in Electrothermally-Actuated MEMS Mirrors
by Mengyuan Li, Qiao Chen, Yabing Liu, Yingtao Ding and Huikai Xie
Micromachines 2017, 8(10), 289; https://doi.org/10.3390/mi8100289 - 25 Sep 2017
Cited by 13 | Viewed by 5268
Abstract
Micro-electro-mechanical system (MEMS) mirrors are widely used for optical modulation, attenuation, steering, switching and tracking. In most cases, MEMS mirrors are packaged in air, resulting in overshoot and ringing upon actuation. In this paper, an electrothermal bimorph MEMS mirror that does not generate [...] Read more.
Micro-electro-mechanical system (MEMS) mirrors are widely used for optical modulation, attenuation, steering, switching and tracking. In most cases, MEMS mirrors are packaged in air, resulting in overshoot and ringing upon actuation. In this paper, an electrothermal bimorph MEMS mirror that does not generate overshoot in step response, even operating in air, is reported. This is achieved by properly designing the thermal response time and the mechanical resonance without using any open-loop or closed-loop control. Electrothermal and thermomechanical lumped-element models are established. According to the analysis, when setting the product of the thermal response time and the fundamental resonance frequency to be greater than Q/2π, the mechanical overshoot and oscillation caused by a step signal can be eliminated effectively. This method is verified experimentally with fabricated electrothermal bimorph MEMS mirrors. Full article
(This article belongs to the Special Issue MEMS Mirrors)
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3200 KiB  
Article
Scanning Micro-Mirror with an Electrostatic Spring for Compensation of Hard-Spring Nonlinearity
by Takashi Izawa, Takashi Sasaki and Kazuhiro Hane
Micromachines 2017, 8(8), 240; https://doi.org/10.3390/mi8080240 - 04 Aug 2017
Cited by 17 | Viewed by 6013
Abstract
A scanning micro-mirror operated at the mechanical resonant frequency often suffer nonlinearity of the torsion-bar spring. The torsion-bar spring becomes harder than the linear spring with the increase of the rotation angle (hard-spring effect). The hard-spring effect of the torsion-bar spring generates several [...] Read more.
A scanning micro-mirror operated at the mechanical resonant frequency often suffer nonlinearity of the torsion-bar spring. The torsion-bar spring becomes harder than the linear spring with the increase of the rotation angle (hard-spring effect). The hard-spring effect of the torsion-bar spring generates several problems, such as hysteresis, frequency shift, and instability by oscillation jump. In this paper, a scanning micro-mirror with an electrostatic-comb spring is studied for compensation of the hard-spring effect of the torsion-bar spring. The hard-spring effect of the torsion-bar spring is compensated with the equivalent soft-spring effect of the electrostatic-comb spring. The oscillation curve becomes symmetric at the resonant frequency although the resonant frequency increases. Theoretical analysis is given for roughly explaining the compensation. A 0.5 mm square scanning micro-mirror having two kinds of combs, i.e., an actuator comb and a compensation comb, is fabricated from a silicon-on-insulator wafer for testing the compensation of the hard-spring in a vacuum and in atmospheric air. The bending of the oscillation curve is compensated by applying a DC voltage to the electrostatic-comb spring in vacuum and atmosphere. The compensation is attributed by theoretical approach to the soft-spring effect of the electrostatic-comb spring. Full article
(This article belongs to the Special Issue MEMS Mirrors)
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11887 KiB  
Article
Operation of a MOEMS Deformable Mirror in Cryo: Challenges and Results
by Frederic Zamkotsian, Patrick Lanzoni, Rudy Barette, Michael Helmbrecht, Franck Marchis and Alex Teichman
Micromachines 2017, 8(8), 233; https://doi.org/10.3390/mi8080233 - 27 Jul 2017
Cited by 12 | Viewed by 5434
Abstract
Micro-opto-electro-mechanical systems (MOEMS) Deformable Mirrors (DM) are key components for next generation optical instruments implementing innovative adaptive optics systems, both in existing telescopes and in the future ELTs. Characterizing these components well is critical for next generation instruments. This is done by interferometry, [...] Read more.
Micro-opto-electro-mechanical systems (MOEMS) Deformable Mirrors (DM) are key components for next generation optical instruments implementing innovative adaptive optics systems, both in existing telescopes and in the future ELTs. Characterizing these components well is critical for next generation instruments. This is done by interferometry, including surface quality measurement in static and dynamical modes, at ambient and in vacuum/cryo. We use a compact cryo-vacuum chamber designed for reaching 10–6 mbar and 160 K in front of our custom Michelson interferometer, which is able to measure performance of the DM at actuator/segment level and at the entire mirror level, with a lateral resolution of 2 µm and a sub-nanometer z-resolution. We tested the PTT 111 DM from Iris AO: an array of single crystalline silicon hexagonal mirrors with a pitch of 606 µm, able to move in tip, tilt, and piston (stroke 5–7 µm, tilt ±5 mrad). The device could be operated successfully from ambient to 160 K. An additional, mainly focus-like, 500 nm deformation of the entire mirror is measured at 160 K; we were able to recover the best flat in cryo by correcting the focus and local tip-tilts on all segments, reaching 12 nm rms. Finally, the goal of these studies is to test DMs in cryo and vacuum conditions as well as to improve their architecture for stable operation in harsh environments. Full article
(This article belongs to the Special Issue MEMS Mirrors)
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5330 KiB  
Article
PZT-Actuated and -Sensed Resonant Micromirrors with Large Scan Angles Applying Mechanical Leverage Amplification for Biaxial Scanning
by Shanshan Gu-Stoppel, Thorsten Giese, Hans-Joachim Quenzer, Ulrich Hofmann and Wolfgang Benecke
Micromachines 2017, 8(7), 215; https://doi.org/10.3390/mi8070215 - 06 Jul 2017
Cited by 20 | Viewed by 6024
Abstract
This article presents design, fabrication and characterization of lead zirconate titanate (PZT)-actuated micromirrors, which enable extremely large scan angle of up to 106° and high frequency of 45 kHz simultaneously. Besides the high driving torque delivered by PZT actuators, mechanical leverage amplification has [...] Read more.
This article presents design, fabrication and characterization of lead zirconate titanate (PZT)-actuated micromirrors, which enable extremely large scan angle of up to 106° and high frequency of 45 kHz simultaneously. Besides the high driving torque delivered by PZT actuators, mechanical leverage amplification has been applied for the micromirrors in this work to reach large displacements consuming low power. Additionally, fracture strength and failure behavior of poly-Si, which is the basic material of the micromirrors, have been studied to optimize the designs and prevent the device from breaking due to high mechanical stress. Since comparing to using biaxial micromirror, realization of biaxial scanning using two independent single-axial micromirrors shows considerable advantages, a setup combining two single-axial micromirrors for biaxial scanning and the results will also be presented in this work. Moreover, integrated piezoelectric position sensors are implemented within the micromirrors, based on which closed-loop control has been developed and studied. Full article
(This article belongs to the Special Issue MEMS Mirrors)
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9745 KiB  
Article
Design and Modeling of Polysilicon Electrothermal Actuators for a MEMS Mirror with Low Power Consumption
by Miguel Lara-Castro, Adrian Herrera-Amaya, Marco A. Escarola-Rosas, Moisés Vázquez-Toledo, Francisco López-Huerta, Luz A. Aguilera-Cortés and Agustín L. Herrera-May
Micromachines 2017, 8(7), 203; https://doi.org/10.3390/mi8070203 - 25 Jun 2017
Cited by 20 | Viewed by 8585
Abstract
Endoscopic optical-coherence tomography (OCT) systems require low cost mirrors with small footprint size, out-of-plane deflections and low bias voltage. These requirements can be achieved with electrothermal actuators based on microelectromechanical systems (MEMS). We present the design and modeling of polysilicon electrothermal actuators for [...] Read more.
Endoscopic optical-coherence tomography (OCT) systems require low cost mirrors with small footprint size, out-of-plane deflections and low bias voltage. These requirements can be achieved with electrothermal actuators based on microelectromechanical systems (MEMS). We present the design and modeling of polysilicon electrothermal actuators for a MEMS mirror (100 μm × 100 μm × 2.25 μm). These actuators are composed by two beam types (2.25 μm thickness) with different cross-section area, which are separated by 2 μm gap. The mirror and actuators are designed through the Sandia Ultra-planar Multi-level MEMS Technology V (SUMMiT V®) process, obtaining a small footprint size (1028 μm × 1028 µm) for actuators of 550 µm length. The actuators have out-of-plane displacements caused by low dc voltages and without use material layers with distinct thermal expansion coefficients. The temperature behavior along the actuators is calculated through analytical models that include terms of heat energy generation, heat conduction and heat energy loss. The force method is used to predict the maximum out-of-plane displacements in the actuator tip as function of supplied voltage. Both analytical models, under steady-state conditions, employ the polysilicon resistivity as function of the temperature. The electrothermal-and structural behavior of the actuators is studied considering different beams dimensions (length and width) and dc bias voltages from 0.5 to 2.5 V. For 2.5 V, the actuator of 550 µm length reaches a maximum temperature, displacement and electrical power of 115 °C, 10.3 µm and 6.3 mW, respectively. The designed actuation mechanism can be useful for MEMS mirrors of different sizes with potential application in endoscopic OCT systems that require low power consumption. Full article
(This article belongs to the Special Issue MEMS Mirrors)
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5794 KiB  
Article
An Electrostatic MEMS Translational Scanner with Large Out-of-Plane Stroke for Remote Axial-Scanning in Multi-Photon Microscopy
by Haijun Li, Xiyu Duan, Gaoming Li, Kenn R. Oldham and Thomas D. Wang
Micromachines 2017, 8(5), 159; https://doi.org/10.3390/mi8050159 - 15 May 2017
Cited by 18 | Viewed by 6039
Abstract
We present an electrostatic microelectromechanical systems (MEMS) resonant scanner with large out-of-plane translational stroke for fast axial-scanning in a multi-photon microscope system for real-time vertical cross-sectional imaging. The scanner has a compact footprint with dimensions of 2.1 mm × 2.1 mm × 0.44 [...] Read more.
We present an electrostatic microelectromechanical systems (MEMS) resonant scanner with large out-of-plane translational stroke for fast axial-scanning in a multi-photon microscope system for real-time vertical cross-sectional imaging. The scanner has a compact footprint with dimensions of 2.1 mm × 2.1 mm × 0.44 mm, and employs a novel lever-based compliant mechanism to enable large vertical displacements of a reflective mirror with slight tilt angles. Test results show that by using parametrical resonance, the scanner can provide a fast out-of-plane translational motion with ≥400 μm displacement and ≤0.14° tilt angle over a wide frequency range of ~390 Hz at ambient pressure. By employing this MEMS translational scanner and a biaxial MEMS mirror for lateral scanning, vertical cross-sectional imaging with a beam axial-scanning range of 200 μm and a frame rate of ~5–10 Hz is enabled in a remote scan multi-photon fluorescence imaging system. Full article
(This article belongs to the Special Issue MEMS Mirrors)
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9305 KiB  
Article
Design and Fabrication of a 2-Axis Electrothermal MEMS Micro-Scanner for Optical Coherence Tomography
by Quentin A. A. Tanguy, Sylwester Bargiel, Huikai Xie, Nicolas Passilly, Magali Barthès, Olivier Gaiffe, Jaroslaw Rutkowski, Philippe Lutz and Christophe Gorecki
Micromachines 2017, 8(5), 146; https://doi.org/10.3390/mi8050146 - 05 May 2017
Cited by 23 | Viewed by 8024
Abstract
This paper introduces an optical 2-axis Micro Electro-Mechanical System (MEMS) micromirror actuated by a pair of electrothermal actuators and a set of passive torsion bars. The actuated element is a dual-reflective circular mirror plate of 1 m m in diameter. This inner mirror [...] Read more.
This paper introduces an optical 2-axis Micro Electro-Mechanical System (MEMS) micromirror actuated by a pair of electrothermal actuators and a set of passive torsion bars. The actuated element is a dual-reflective circular mirror plate of 1 m m in diameter. This inner mirror plate is connected to a rigid frame via a pair of torsion bars in two diametrically opposite ends located on the rotation axis. A pair of electrothermal bimorphs generates a force onto the perpendicular free ends of the mirror plate in the same angular direction. An array of electrothermal bimorph cantilevers deflects the rigid frame around a working angle of 45 ∘ for side-view scan. The performed scans reach large mechanical angles of 32 ∘ for the frame and 22 ∘ for the in-frame mirror. We denote three resonant main modes, pure flexion of the frame at 205 Hz , a pure torsion of the mirror plate at 1.286 kHz and coupled mode of combined flexion and torsion at 1.588 kHz . The micro device was fabricated through successive stacks of materials onto a silicon-on-insulator wafer and the patterned deposition on the back-side of the dual-reflective mirror is achieved through a dry film photoresist photolithography process. Full article
(This article belongs to the Special Issue MEMS Mirrors)
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3093 KiB  
Article
A Large-Size MEMS Scanning Mirror for Speckle Reduction Application
by Fanya Li, Peng Zhou, Tingting Wang, Jiahui He, Huijun Yu and Wenjiang Shen
Micromachines 2017, 8(5), 140; https://doi.org/10.3390/mi8050140 - 03 May 2017
Cited by 23 | Viewed by 6397
Abstract
Based on microelectronic mechanical system (MEMS) processing, a large-size 2-D scanning mirror (6.5 mm in diameter) driven by electromagnetic force was designed and implemented in this paper. We fabricated the micromirror with a silicon wafer and selectively electroplated Ni film on the back [...] Read more.
Based on microelectronic mechanical system (MEMS) processing, a large-size 2-D scanning mirror (6.5 mm in diameter) driven by electromagnetic force was designed and implemented in this paper. We fabricated the micromirror with a silicon wafer and selectively electroplated Ni film on the back of the mirror. The nickel film was magnetized in the magnetic field produced by external current coils, and created the force to drive the mirror’s angular deflection. This electromagnetically actuated micromirror effectively eliminates the ohmic heat and power loss on the mirror plate, which always occurs in the other types of electromagnetic micromirrors with the coil on the mirror plate. The resonant frequency for the scanning mirror is 674 Hz along the slow axis, and 1870 Hz along the fast axis. Furthermore, the scanning angles could achieve ±4.5° for the slow axis with 13.2 mW power consumption, and ±7.6° for the fast axis with 43.3 mW power consumption. The application of the MEMS mirror to a laser display system effectively reduces the laser speckle. With 2-D scanning of the MEMS mirror, the speckle contrast can be reduced from 18.19% to 4.58%. We demonstrated that the image quality of a laser display system could be greatly improved by the MEMS mirror. Full article
(This article belongs to the Special Issue MEMS Mirrors)
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3274 KiB  
Article
Modeling of MEMS Mirrors Actuated by Phase-Change Mechanism
by David Torres, Jun Zhang, Sarah Dooley, Xiaobo Tan and Nelson Sepúlveda
Micromachines 2017, 8(5), 138; https://doi.org/10.3390/mi8050138 - 26 Apr 2017
Cited by 7 | Viewed by 5404
Abstract
Given the multiple applications for micro-electro-mechanical system (MEMS) mirror devices, most of the research efforts are focused on improving device performance in terms of tilting angles, speed, and their integration into larger arrays or systems. The modeling of these devices is crucial for [...] Read more.
Given the multiple applications for micro-electro-mechanical system (MEMS) mirror devices, most of the research efforts are focused on improving device performance in terms of tilting angles, speed, and their integration into larger arrays or systems. The modeling of these devices is crucial for enabling a platform, in particular, by allowing for the future control of such devices. In this paper, we present the modeling of a MEMS mirror structure with four actuators driven by the phase-change of a thin film. The complexity of the device structure and the nonlinear behavior of the actuation mechanism allow for a comprehensive study that encompasses simpler electrothermal designs, thus presenting a general approach that can be adapted to most MEMS mirror designs based on this operation principle. The MEMS mirrors presented in this work are actuated by Joule heating and tested using optical techniques. Mechanical and thermal models including both pitch and roll displacements are developed by combining theoretical analysis (using both numerical and analytical tools) with experimental data and subsequently verifying with quasi-static and dynamic experiments. Full article
(This article belongs to the Special Issue MEMS Mirrors)
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4274 KiB  
Article
In-Plane Optical Beam Collimation Using a Three-Dimensional Curved MEMS Mirror
by Yasser M. Sabry, Diaa Khalil, Bassam Saadany and Tarik Bourouina
Micromachines 2017, 8(5), 134; https://doi.org/10.3390/mi8050134 - 25 Apr 2017
Cited by 10 | Viewed by 6389
Abstract
The collimation of free-space light propagating in-plane with respect to the substrate is an important performance factor in optical microelectromechanical systems (MEMS). This is usually carried out by integrating micro lenses into the system, which increases the cost of fabrication/assembly in addition to [...] Read more.
The collimation of free-space light propagating in-plane with respect to the substrate is an important performance factor in optical microelectromechanical systems (MEMS). This is usually carried out by integrating micro lenses into the system, which increases the cost of fabrication/assembly in addition to limiting the wavelength working range of the system imposed by the dispersion characteristic of the lenses. In this work we demonstrate optical fiber light collimation using a silicon micromachined three-dimensional curved mirror. Sensitivity to micromachining and fiber alignment tolerance is shown to be low enough by restricting the ratio between the mirror focal length and the optical beam Rayleigh range below 5. The three-dimensional curvature of the mirror is designed to be astigmatic and controlled by a process combining deep, reactive ion etching and isotropic etching of silicon. The effect of the micromachining surface roughness on the collimated beam profile is investigated using a Fourier optics approach for different values of root-mean-squared (RMS) roughness and correlation length. The isotropic etching step of the structure is characterized and optimized for the optical-grade surface requirement. The experimental optical results show a beam-waist ratio of about 4.25 and a corresponding 12-dB improvement in diffraction loss, in good agreement with theory. This type of micromirror can be monolithically integrated into lensless microoptoelectromechanical systems (MOEMS), improving their performance in many different applications. Full article
(This article belongs to the Special Issue MEMS Mirrors)
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10567 KiB  
Article
The Exploration for an Appropriate Vacuum Level for Performance Enhancement of a Comb-Drive Microscanner
by Rong Zhao, Dayong Qiao, Xiumin Song and Qiaoming You
Micromachines 2017, 8(4), 126; https://doi.org/10.3390/mi8040126 - 16 Apr 2017
Cited by 8 | Viewed by 4807
Abstract
In order to identify the influence of the vacuum environment on the performance of a comb-drive microscanner, and indicate the optimum pressure for enhancing its performance, a comb-drive microscanner fabricated on silicon-on-insulator (SOI) substrate was prepared and tested at different pressures, and the [...] Read more.
In order to identify the influence of the vacuum environment on the performance of a comb-drive microscanner, and indicate the optimum pressure for enhancing its performance, a comb-drive microscanner fabricated on silicon-on-insulator (SOI) substrate was prepared and tested at different pressures, and the characteristics in vacuum were obtained. The test results revealed that the vacuum environment enhanced the performance in the optical scanning angle, and decreased the actuation voltage. With a 30 V driving voltage applied, the microscanner can reach an optical scanning angle of 44.3° at a pressure of 500 Pa. To obtain an enhancement in its properties, only a vacuum range from 100 to 1000 Pa is needed, which can be very readily and economically realized and maintained in a vacuum package. Full article
(This article belongs to the Special Issue MEMS Mirrors)
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5736 KiB  
Article
Large-Aperture kHz Operating Frequency Ti-alloy Based Optical Micro Scanning Mirror for LiDAR Application
by Liangchen Ye, Gaofei Zhang and Zheng You
Micromachines 2017, 8(4), 120; https://doi.org/10.3390/mi8040120 - 10 Apr 2017
Cited by 48 | Viewed by 12320
Abstract
A micro scanning mirror is an optical device used to scan laser beams which can be used for Light Detection and Ranging (LiDAR) in applications like unmanned driving or Unmanned Aerial Vehicle (UAV). The MEMS scanning mirror’s light-weight and low-power make it a [...] Read more.
A micro scanning mirror is an optical device used to scan laser beams which can be used for Light Detection and Ranging (LiDAR) in applications like unmanned driving or Unmanned Aerial Vehicle (UAV). The MEMS scanning mirror’s light-weight and low-power make it a useful device in LiDAR applications. However, the MEMS scanning mirror’s small aperture limits its application because it is too small to deflect faint receiving light. In this paper, we present a Ti-alloy-based electromagnetic micro scanning mirror with very large-aperture (12 mm) and rapid scanning frequency (1.24 kHz). The size of micro-scanner’s mirror plate reached 12 mm, which is much larger than familiar MEMS scanning mirror. The scanner is designed using MEMS design method and fabricated by electro-sparking manufacture method. As the experimental results show, the resonant frequency of the micro scanning mirror is 1240 Hz and the optical scanning angle can reach 26 degrees at resonance frequency when the actuation current is 250 mApp. Full article
(This article belongs to the Special Issue MEMS Mirrors)
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8221 KiB  
Article
Multi-Response Optimization of Electrothermal Micromirror Using Desirability Function-Based Response Surface Methodology
by Muhammad Mubasher Saleem, Umar Farooq, Umer Izhar and Umar Shahbaz Khan
Micromachines 2017, 8(4), 107; https://doi.org/10.3390/mi8040107 - 01 Apr 2017
Cited by 7 | Viewed by 6539
Abstract
The design of a micromirror for biomedical applications requires multiple output responses to be optimized, given a set of performance parameters and constraints. This paper presents the parametric design optimization of an electrothermally actuated micromirror for the deflection angle, input power, and micromirror [...] Read more.
The design of a micromirror for biomedical applications requires multiple output responses to be optimized, given a set of performance parameters and constraints. This paper presents the parametric design optimization of an electrothermally actuated micromirror for the deflection angle, input power, and micromirror temperature rise from the ambient for Optical Coherence Tomography (OCT) system. Initially, a screening design matrix based on the Design of Experiments (DOE) technique is developed and the corresponding output responses are obtained using coupled structural-thermal-electric Finite Element Modeling (FEM). The interaction between the significant design factors is analyzed by developing Response Surface Models (RSM) for the output responses. The output responses are optimized by combining the individual responses into a composite function using desirability function approach. A downhill simplex method, based on the heuristic search algorithm, is implemented on the RSM models to find the optimal levels of the design factors. The predicted values of output responses obtained using multi-response optimization are verified by the FEM simulations. Full article
(This article belongs to the Special Issue MEMS Mirrors)
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