一种垂直梳齿驱动V型梁微镜设计

设计了一种垂直梳齿驱动的V型扭转梁支撑的微镜器件.采用有限元仿真和解析方法对该器件进行了静态和动态分析.在100V直流电压下,镜面转角可达0.7°,能够满足镜而扫描所需要的起始角.同时对比了不同支撑梁结构下的前五阶模态频率以及前两阶频率比,并分析了不同梁间距以及V型梁夹角下各个参数的变化趋势,得出了使微扭转镜工作在最稳...     

用于硅基氮化镓可调微镜的静电梳齿型微驱动器设计

提出并设计了一种用于硅基氮化镓(GaN)可调微镜的静电梳齿型微驱动器.利用有限元软件建立了该器件的几何结构模型,对器件的结构进行了仿真优化.此外,采用微机电系统(MEMS)加工工艺,制作出了用于硅基氮化镓可调微镜的梳齿型微驱动器,并对其驱动特性进行测试.测试结果表明:所制作的微驱动器的位移随着电压的变化呈二次方关系,与仿真结果基本一致.当加载驱动电压为200 V时,微驱动器的驱动位移可达到1.08 μm.     

梳齿分布结构对静电驱动二维微扫描镜机械转角的影响

为增大静电驱动二维微扫描镜的机械转角,基于非线性动力学理论研究了不同梳齿结构对其振幅的影响,理论上得到发散型梳齿分布相较于平行型梳齿分布具有更大的机械转角。此外,采用绝缘体上硅(SOI)加工工艺设计并制作了这两种结构的微扫描镜,并对其相关特性进行了测试。测试结果表明:在相同的驱动电压下,发散型结构始终都比平行型结构具有更大的机械转角,与仿真结果基本一致;当加载驱动电压为42 V的方波信号时,发散型结构扫描镜的可动框架和镜面的最大机械转角可以达到12.3°、13.49°,而平行型结构扫描镜的可动框架和镜面的最大机械转角则为10.25°、11.68°。     

一种集成微力检测的压电式微夹钳

针对微装配任务设计了一种双悬臂梁结构的压电双晶片微夹钳，该微夹钳由两个压电双晶片驱动．建立了压电双晶片的复合梁模型，并对它的微位移—电压特性、夹持力—应变特性进行了数学分析．通过检测悬臂梁根部的应变信号实现对微夹钳夹持力的检测．实验证明该微夹钳工作可靠，能够满足微装配机器人装配任务的要求．     

几种基于MEMS的纳米梁制作方法研究

特征尺度在纳米量级的梁结构是多种纳机电器件的基本结构.提出了几种基于MEMS技术的纳米梁制作方法,通过利用MEMS技术中材料与工艺的特性实现单晶硅纳米梁的制作.在普通(111)硅片上,利用各向异性湿法腐蚀对(111)面腐蚀速率极低的特性,通过干法与湿法腐蚀相结合制成厚度在100 nm以下的纳米梁.该方法不使用SOI硅片,有效控制了成本.在(100)SOI硅片上,通过氧化减薄的方法得到厚度在100 nm以下的多种纳米梁,由于热氧化的精度高,一致性好,该方法重复性与一致性均较好.在(110)SOI硅片上,利用硅的各向异性腐蚀特性以及(110)硅片的晶向特点,制作宽度在100 nm以下的纳米梁,梁的两个侧面是(111)面.     

MEMS近红外光谱仪微镜驱动控制系统研发

针对微机电系统（MEMS）近红外光谱仪中MEMS微镜驱动系统的耦合与复杂扰动问题,提出了一种基于扰动观测器（DOB）与模型预测控制（MPC）的复合控制结构。通过分析MEMS微镜的驱动工作原理,建立MEMS微镜偏转角与驱动电压的传递函数模型,设计了MPC以消除系统耦合,通过分析系统扰动模型,设计了DOB实现对系统内部与外部扰动的集中监测。仿真研究与实验测试结果表明：基于DOB MPC复合结构的MEMS微镜驱动控制系统,既可以有效抑制系统的外部扰动,又可以抑制由模型失配和变量耦合导致的内部扰动。     

一种高灵敏度硅微机械陀螺的设计与制造

设计与制造了一种高灵敏度的硅微机械陀螺。陀螺用静电来驱动,用连接成惠斯顿电桥的压阻式力敏电阻应变计来检测。主梁、微梁 质量块结构实现了高灵敏度。比较硬的主梁提供了一定的机械强度,并且提供了高共振频率。微梁很细,检测时微梁沿轴向直拉直压。力敏电阻应变计就扩散在微梁上,质量块很小的挠动就能在微梁上产生很大的应力,输出很大的信号。5V条件下,陀螺检测部分的理论灵敏度达到27.45mV/gn。压阻式四端器件用来监测驱动振幅,可以反馈补偿压阻的温度系数。检测模态的Q值达260使陀螺能在大气下工作。陀螺利用普通的n型硅片制造,为了刻蚀高深宽比的结构,使用了深反应离子刻蚀(DRIE)工艺。     

多场耦合下PLZT陶瓷光致电场效应及其应用

针对现有数学模型对高能紫外光束照射下PLZT陶瓷光生电压实验变化规律无法进行合理解释的问题,基于多物理场耦合机制分析构建了PLZT陶瓷多场耦合下的光致电场数学模型,并对光致电场实验曲线进行了理论分析,然后针对光生电压控制提出了单片PLZT陶瓷ON-OFF闭环控制和双片PLZT陶瓷双光源协调激励控制策略,取得了较好的控制效果,探讨了PLZT陶瓷作为光控非接触式电动势源的可行性以及在微机电系统供能器件的应用前景,在此基础上,提出了光电-静电复合驱动微镜和PLZT陶瓷-介电弹性薄膜复合驱动的光控微泵装置.     

高速MEMS扫描微镜动态变形特性研究

扭转镜面的动态形变是影响显示成像用MEMS扫描微镜光学分辨率的主导因素,研究了高速转动的MEMS扫描微镜的动态形变特性,得到了相关有用的结论。结果表明当MEMS扫描微镜镜面几何尺寸一定时,如果要获得系统衍射极限光学分辨率,需要对转动频率,扭转角度和镜面厚度进行优化设计和选择,简单通过增加镜面厚度保证光学分辨率的方法不利于MEMS扫描微镜综合性能的改善和提高。     

（中国微米纳米技术学会文章）一种硅微机械结构振动幅度的电学测量方法及实验研究

本文针对硅微机械结构振动幅度由于封装难以计算机视觉测量及电学测量中的精度受接口电路参数影响的问题,在对静电梳齿驱动、平板电容检测的硅微谐振结构进行建模分析后,提出基于单边带电压比的电学测量振动幅度的方法并分析了测量方法的原理。实验表明研制的某硅微机械谐振加速度计在受迫振动下的振动幅度为0.25um,频谱分析还表明存在上电噪声引起的振动幅度,该测试方法还能应用于硅微谐振结构的谐振频率测量,同时为高品质因数的硅微机械谐振结构的可静电自激驱动提供了依据。     

Electromechanical characterization of a new micro programmable blazed grating by laser Doppler vibrometry

The prototype of a new micro programmable blazed grating driven electrostatically was fabricated using a two-layer polysilicon surface micromachining process. And initially, to characterize its electromechanical performances, such as the driving voltage versus displacement relationship, frequency response and step response, the laser Doppler vibrometry was employed. The measured results reveal the pull-in voltage of 110–115 V, resonant frequency of 78 KHz, quality factor of 2.89, adjusting time of 12 μs, and damping ratio of ~0.68 for the achieved grating sample. As a result, the grating functions well electromechanically. As for its optical performances, a number of optical experiments are in progress.     

Scanning micromirrors fabricated by an SOI/SOI wafer-bonding process

MEMS scanning micromirrors have been proposed to steer a modulated laser beam in order to establish secure optical links between rapidly moving platforms. An SOI/SOI wafer-bonding process has been developed to fabricate scanning micromirrors using lateral actuation. The process is an extension of established SOI technology and can be used to fabricate stacked high-aspect-ratio structures with well-controlled thicknesses. Fabricated one-axis micromirrors scan up to 21.8/spl deg/ optically under a dc actuation voltage of 75.0 V, and have a resonant frequency of 3.6 kHz. Fabricated two-axis micromirrors scan up to 15.9/spl deg/ optically on the inner axis at 71.8 V and 13.2/spl deg/ on the outer axis at 71.2 V. The micromirrors are observed to be quite durable and resistant to shocks. Torsional beams with T-shaped cross sections are introduced to replace rectangular torsional beams in two-axis MEMS micromirrors, in order to reduce the cross-coupling between the two axial rotations. Fabricated bidirectional two-axis micromirrors scan up to /spl plusmn/7/spl deg/ on the outer-axis and from -3/spl deg/ to 7/spl deg/ on the inner-axis under dc actuation.     

Tunable Pneumatic Microoptics

A new class of tunable and actuated microoptical devices is presented: pneumatic microoptics. Using microelectromechanical system fabrication technology extended by the use of polydimethylsiloxane (PDMS) membranes, tunable microlenses, and lens arrays, actuated micromirrors with large tilt angles and tip-tilt piston mirrors have been designed and fabricated. Actuation is by pressure: Gas- or liquid-filled microfluidic cavities are employed to distend the microfabricated PDMS structures which then act as a lens surface or as an actuator for a micromirror. Thermopneumatic actuation is also employed for completely integrated tunable optical systems in which all actuator and optical components are fabricated on-chip. The technology is particularly promising for microsystem applications in which significant movement is required but high voltages or external fields are impractical. [2007-0301].     

A MEMS-based tracking milli-mirror for high-density optical disk drives

We present a new MEMS-based milli-mirror for precise tracking in high-density optical disk drives (ODDs). The device consists of a torsionally suspended mirror plate, one pair of torsion springs, which support the mirror plate and offer a restoring torque, and two pairs of electrodes attached to the mirror plate and glass substrate. The dimensions of mirror plate and torsion springs were determined so that a 5 V dc bias ±4.5 V ac drive voltage would provide the mirror with ±0.02° rotation to transmit laser beam spot on spinning disk. The MEMS-based milli-mirror was successfully fabricated using MEMS technology. Displacement–voltage linearization scheme was implemented by differential voltage driving. The static and dynamic performances of mirror prototype, such as capacitance versus driving voltage, rotation angle versus driving voltage, and resonant frequency were characterized and compared well with the simulation solutions. The mechanical resonant frequency of the mirror is expected to be high enough to satisfy the requirement of the servo bandwidth of precise tracking-control in high-density blue-laser optical disk drive.     

Design and realization of micro structured surfaces for thermodynamic applications

The functionality of surfaces, especially for thermodynamic applications, can be enhanced by help of a specific surface modification. Therefore this study investigates different selected surface structures and their influence on the heat transfer capability. Specific micro geometries are in focus of this research. A systematic design and a determination of appropriate thermodynamic micro structures by the help of FEM multiphysics simulations were executed. Afterwards the investigated structures were fabricated applying electrochemical and laser beam machining. Furthermore a systematic analysis of the exactness and the surface quality was carried out, which underlines the potential of these procedures for micro structuring of surfaces for thermodynamic applications.     

Requirements of an industrially applicable microcutting process for steel micro-structures

 Micro-cutting offers good potentialities in order to manufacture small and medium lot sizes of micro-parts with arbitrary geometry at an economically reasonable expense. Either by direct machining or as a means to fabricate moulds for micro injection moulding, the major advantages turn out to be large removal rates, good compliance with tolerance ranges, high surface quality and a wide choice of materials which can be processed. Particularly if highly wear resistant materials are to be processes, as it is the case in mould fabrication for powder injection moulding, micro cutting of steel is a very eligible option. Consequently, the possibility to manufacture wear resistant micro structures of high aspect ratios by mechanical cutting is demonstrated with regard to its specific requirements in terms of transferability of the laboratory process into an industrial manufacturing process. Accordingly the paper focuses on repeatability of machining results and machining capabilities. Received: 10 August 2001/Accepted: 24 September 2001     

Modeling, microfabrication and experiments of a free–free cantilever bistable micro mechanism supported with a diamond configuration

Bistable micro mechanisms are gaining great attention in MEMS applications. This paper presents the mechanical modeling and experimental characterization of a bistable torsion/cantilever micro latching mechanism for performing low power bistable relay applications. The bistable micro mechanism consists of two cantilevers which form symmetrical rocker levers. The free–free cantilever is suspended by a diamond skeleton which in turn is attached to a torsion cantilever. A permanent magnet is placed beside for holding the closed state with a permalloy soft magnetic circuit. The special diamond support is designed to enhance the stiffness of the overhang beams. In order to deduce the spring stiffness of system, a mechanical modeling of the leveraged torsion/cantilever system was performed by Castigliano’s theorem. Meanwhile, the magnetostatic latching force was also deduced by the Maxwell electromagnetism theory. Then the device has been prepared by a laminated copper sacrificial layer process. This process can facilitate the fabrication complexities of traditional magnetic device with coil structures. Finally, mechanical performance was characterized by an atomic force microscopy, combined with finite element simulation using ANSYS^™ package and analysis model as well. Two stable states of the micro mechanism were hold successfully with no power consumption by interferoscope profilometry of WYKO optical profiling system.     

Conductive Blended Polymer MEMS Microresonators

This paper presents an all-polymer microelectromechanical system technology in which a crosslinker is used to modify the electromechanical properties. The structural material of these microelectromechanical systems (MEMS) structures is a poly(3,4-ethylenedioxythiophene)/polystyrene sulfonate/polymethyl methacrylate (PEDOT/PSS/PMMA) blended conductive polymer. Microbridge resonators are fabricated using surface micromachining on glass substrates. The electromechanical properties of the polymer microbridges are studied using electrostatic actuation and optical and electrical detection. The resonance frequency of the polymer bridges occurs in the MHz range, with quality factors of the order of 100 when measured in vacuum. Addition of a silane-based crosslinker increases the Young's modulus of the polymer structural material which is reflected in higher resonance frequency, higher pull-in voltage, better long-term stability of the electrical conductivity, and in a decrease in the quality factor of the resonator. The mechanical properties of the polymer resonators are strongly affected by the residual stress because of the low Young's modulus, and by the measurement frequency and the measurement temperature due to the viscoelastic properties of the polymer structural material     

Microstructuring of silicon by electro-discharge machining (EDM) — part I: theory

Currently, nearly all microcomponents are fabricated by micro-electronic production technologies like etching, deposition and other (photo) lithographic techniques. In this way, main emphasis has been put on surface micromechanics. The major challenge for the future will be the development of real three-dimensional microstructures. The main objective of the proposed research is the development of a production technology for three-dimensional micromechanical structures together with a study of the mechanical properties of these structures. Electrodischarge machining (EDM) is a versatile technique which is very well suited for machining complex microstructures. This paper starts with an overview of EDM technology, the current state-of-the-art of micro EDM, and a comparison of EDM with other micromachining technologies. Afterwards, the basic parameters for EDM of silicon are derived. It will be demonstrated that EDM of silicon is not only feasible, but also forms an interesting, powerful and complementary alternative to traditional silicon micromachining.     

Analysis and test of a new MEMS micro-actuator

A large-deformation and low-voltage micro actuator is proposed in this paper to overcome the problems of high voltage and undersized deformation of electrostatic micro actuator. The principle of the proposed actuator is based on vertical-horizontal bending. Dynamic equations of the micro actuator under axial and horizontal loading are built based on Lagrange–Maxwell electromechanical dynamics equations. In addition, the influences of thermal stress, axial electrostatic force and squeezing force are analyzed. Furthermore, the horizontal distributed load and axial load are equivalent to horizontal centralized load based on the Runge–Kutta algorithm and finite difference method. The relationships of deformation with driving voltage, regulation voltage, and axial compression quantity and temperature difference are achieved by simulation. Simulation results show that the deformation of the proposed actuator is as high as 10.861 μm when the driving voltage is 16 V. The deformation of proposed micro actuator is larger than that of the existing one. Finally, the simulation results are verified by experiment and agree well with experiment results.