压电厚膜驱动的高刚度微变形镜的制备

研究制备了一种压电厚膜微变形镜,微变形镜的连续薄膜式单晶硅镜面由61单元压电厚膜致动器阵列驱动.以镜面冲程与工作频带宽为目标,对微变形镜的结构参数进行优化设计,根据优化参数采用硅微加工技术试制了61单元致动器的微变形镜.镜面、压电陶瓷与弹性支撑层厚度分别为100μm、60μm与60μm,单元间距为5mm,通光口径为40 mm.对制备的样品性能进行了测试,微变形镜在100 V电压驱动下变形量约为2.84μm,工作带宽大于10 kHz.测试结果还表明压电厚膜驱动的微变形镜拥有较高刚度,有利于提高镜面初始平面度.     

基于锆钛酸铅薄膜的变形镜微致动器

以锆钛酸铅（PZT）薄膜作为驱动材料,制备了变形镜的微致动器阵列．使用有限元软件对致动器进行了模拟仿真,得到了驱动器上电极尺寸、Si弹性层厚度等参数对致动器性能的影响,获得了最优化的致动器结构．以钙钛矿相的镍酸镧（LNO）作为PZT薄膜在Pt衬底上生长的缓冲层,增强了PZT薄膜的（100）取向,减小了PZT薄膜的内部应力,提高了致动器的驱动性能．最终制备出的1μm厚PZT薄膜驱动的变形镜微致动器,在10V直流电压的激励下,具有2．0μm的变形量．以PZT薄膜作为驱动材料制备的变形镜微致动器阵列,对变形镜致动器的微型化和系统集成度的提高具有重要意义．     

MEMS变形镜用PZT厚膜致动器阵列的制备及性能表征

提出了一种基于锆钛酸铅(PZT)压电厚膜致动器阵列驱动的MEMS微变形镜,建立了该微变形镜的结构模型,分析了其结构中各层厚度对其性能的影响.PZT压电厚膜是通过基于PZT压电陶瓷体材料的湿法刻蚀技术制备的,刻蚀液为1BHF2HCl4NH4 Cl4H2O.以数字锁相方法测试了压电厚膜的介电性能,在100 kHz以下时,其介电常数和介质损耗分别优于2400和3%.利用悬臂梁方法测试了压电厚膜的也.横向压电系数,约为-250 pm/V.制备了4×4阵列的压电致动器阵列.采用激光多普勒测试压电致动器的电压位移曲线,在100 V的电压驱动下致动器的变形量大约为2.2/μm;测试了致动器的频率响应,其谐振频率高于100 kHz;致动器刚度大,带负载能力强.     

用于MEMS变形镜的双电极压电厚膜致动器

提出了一种用于MEMS变形镜的双电极驱动的压电陶瓷（PZT）厚膜致动器．采用有限元方法分析致动器变形时的应力分布情况,优化了内外圈电极尺寸,制作了61单元六边形分布的致动器阵列．测试结果表明,致动器在100V工作电压下的;中程约为6．6μm,谐振频率为58kHz,位移迟滞为8％～9％,通过采用单边电压一位移曲线的策略有效降低了位移迟滞,并进一步提出了分时驱动的电路方案．     

微致动器用于翼面流场主动控制规律研究

面向主动流动控制研发了气泡型微致动器及其阵列技术和MEMS合成射流器技术．对气泡型微致动器参与下的飞行器翼面流场进行了数值模拟,并结合翼型开展了风洞实验,研究了气泡型微致动器对气动性能的影响规律．阐述了微型合成射流器及其微流场特性,研究了合成射流抑制失速、提高升力的机理．结果表明,在翼型上对微致动器进行合理布置,采用适当的控制参数,可以实现对翼面绕流的有益主动控制,达到增加升力、改善失速特性等目的．     

新型纳米级微位移致动器的设计

磁致伸缩型微位移致动器通常采用多晶或孪晶结构材料作为驱动单元 ,由于晶界和孪晶界对畴壁的移动具有阻碍作用 ,其低场下的位移输出较小 ,调控精度受到较大影响。采用Tb Dy Fe单晶材料可以有效解决这一问题 ,本文介绍了采用这一单晶材料设计的新型高精度微位移致动器以及致动器的结构和数控电源     

IPMC微泵驱动膜的设计及结构优化

利用离子聚合物人工肌肉(IPMC)固有的电致动性能,设计了圆盘形、S形、条形及扇形4种不同结构的致动膜,选择最优结构的驱动膜以驱动微泵。制备了一系列IPMC悬臂梁状致动器,利用激光位移传感器测出不同条件下致动器产生的位移。ANSYS软件下,利用位移推导出IPMC单元体的弯矩,以此计算衡量微泵的体积变化和最大工作压力。同时,分析了泵膜形状、半径、厚度、驱动电压对泵体积变化和工作压力的影响。结果表明:较之于其它3种泵膜,扇形泵膜的体积变化量最大;泵膜半径的增加有利于增大体积变化量;泵膜厚度的增加有利于增加工作压力;适当地增加驱动电压,可同时提高其工作压力和体积变化量。     

基于压电致动器的微动隔振平台系统

为实现微仪器隔振平台的自适应控制,对第三代压电致动器顶杆部件进行了改进,并将其直接应用于微隔振系统,隔振效果不是很理想。为此,对致动器进行了系统在线建模,从理论上分析了导致结果不理想的原因,给出了一种改进方法,通过理论建模分析和试验研究,结果表明:该方法虽然降低了致动器位移增益,但具有较好的隔振效果。     

超磁致仲缩材料在心血管支架加工中微进给补偿控制中的研究

基于超磁致伸缩材料特性对微位移进给进行研究,设计了磁致伸缩致动器应用于心血管支架的加工,建立了致动器的传递函数模型。同时针对超磁致伸缩材料受温度,预紧力等因素影响对位移输出产生较大偏差,设计了PID调节器,并对磁致伸缩致动器控制系统给出了基于MATLAB的仿真,并在此基础上进行了离散化,得到了数字控制系统,并应用到实际中,并对实际输出位移进行对比。经过PID闭环控制调剂后,位移输出有了明显的稳定。     

卷对卷制备微透镜阵列防伪膜

目的制备一种高线数(200线以上)的微透镜阵列防伪膜,改变国内印刷包装行业对微透镜阵列防伪膜的制备停留在200线以下的圆点微透镜阵列防伪膜的现状。方法采用卷到卷、圆压圆的制备工艺,以聚碳酸酯为原料,采用激光微刻技术制备模具,压印温度设置为139℃,转移速度设置为5m/min。结果制得一种正六角形半球状微透镜阵列防伪膜,微透镜边长为32μm,栅距为48μm,膜厚为121μm,根据微透镜阵列结构参数关系折算后光栅线数为529线。结论实现了高线数、高填充系数的微透镜阵列防伪膜的制备,提供了一种工艺简单、适于批量生产的微透镜阵列防伪膜制备方法。     

Properties of piezoelectric actuator on silicon membrane, prepared by screen printing method

Characteristics of piezoelectric actuator on Si membrane were investigated. Si membranes were fabricated as a function of size using bulk micromachining method. Bottom electrode Ag–Pd and piezoelectric thick films were fabricated using screen printing method, respectively. Piezoelectric thick films were sintered by rapid thermal annealing (RTA). Top electrodes Pt were deposited by DC sputtering system. We analyzed micro structure by scanning electron microscope (SEM) and investigated dynamic properties by MTI2000. Therefore, piezoelectric thick film on Si membrane had P_r of 15.7 μC cm⁻². The maximum displacement of micro actuator had 0.05 μm. We find the combination of thick film printing and MEMS process to form a Si membrane micro actuator.     

Deflection characteristics of a trapezoidal multilayer in-plane bending piezoelectric actuator

A novel multilayer split-morph actuator has been designed and fabricated using the thick film screen-printing technology. Deflection characteristics of the split-morph actuator have been investigated by theoretical analysis and experimental measurement. The results indicate that the tip displacement is inversely proportional to the thickness of each piezoelectric layer, but is independent of the number of layers and the total thickness of the actuator. The displacement/voltage sensitivity of the trapezoidal actuator is larger than that of the rectangular design, assuming both have the same width of clamped end and the same thickness of the piezoelectric layers. The maximum displacement/voltage sensitivity of 0.157 micron/V was obtained with a split-morph actuator with 30-micron thick layers. The proposed actuator is a promising candidate for the secondary fine-tuning actuator of a dual stage head-positioning servo system in high density hard disk drives.     

Levitation Force Investigation of Bulk HTSC Above Halbach PMG with Different Cross-Section Physical Dimensions by 3D-Modeling Numerical Method

The levitation force of a bulk high temperature superconductor (HTSC) over Halbach permanent magnet guideways (PMG) with different cross-section configuration is studied by numerical method. The Halbach PMG is composed of three host permanent magnets (HPMs) and two slave permanent magnets (SPMs). One cylindrical bulk HTSC with a diameter of 30 mm and height of 15 mm is used. The 3D-modeling is formulated by the H-method. The numerical resolving codes are practiced using finite element method (FEM). The E-J power law is used to describe the electric current nonlinear characteristics of bulk HTSC. By the method, the influence of the cross-section physical dimensions of Halbach PMG on the levitation forces of bulk HTSC levitated above the PMG is studied. The simulation results show that increasing the width of SPM ( \(W_\mathrm{SPM})\) can enhance the bulk HTSC levitation performance immediately under the condition of keeping the ratio of \(W_\mathrm{HPM}\) ( \(W_\mathrm{HPM}\) : the width of HPM) to \(W_\mathrm{SPM}\) between 1.6 and 1.8, the ratio of td (the height of the PMG) to \(W_\mathrm{HPM }\) between 1.2 and 1.4. By the method, the bulk HTSC better levitation performance can be expected.     

Magnetic Circuit Design for Six-Wire Suspension Type Actuator in a Super Multioptical Pickup

We have developed a new magnetic circuit consisting of eight permanent magnets with special placement order. Here, we analyze the magnetic flux density distribution, the driving force distribution, and the interference force using the finite-element method. The driving sensitivity of the actuator at low frequency is nearly twice that of a conventional actuator. We have built several samples and compared their performance with simulation data. The results prove the validity of the proposed magnetic circuit and the design method.     

A Planar Actuator with a Small Mover Traveling Over Large Yaw and Translational Displacements

We report a three-degree-of-freedom actuator with a small mover that can travel over large displacements on a plane. Such direct drives with multiple degrees of freedom are an emerging technology because of their high performance. Previously, we designed planar actuators capable of generating thrusts anywhere in the movement area and successfully demonstrated the two-dimensional drive of the actuator in the translational direction. However, during translational motion control on the plane, a slight oscillatory yaw motion occurred. Thrusts and torques of the actuator are proportional to the - and -axis currents, which generate flux densities with 90 and 0 phase-leads, respectively, from the flux density generated by the permanent magnets of the mover. Therefore, the thrusts and torques can be generated independently by the - and -axis current control. In our new design, we use a decoupling control on the planar actuator to control both yaw and translational motions on the plane. We describe the experimentally obtained drive characteristics of this actuator. The experimental results indicate that the mover can travel over large yaw and translational displacements independently and simultaneously with relatively precise positioning and response. Thus, we have demonstrated satisfactory performance of a planar actuator with three degrees of freedom.     

新型双向加载MEMS微执行器动力学分析

传统横向单向加载MEMS静电微执行器存在位移过小或驱动电压过大等问题.本文提出一种纵横双向加载的新型硅基静电执行器模型.基于拉格朗日-麦克斯韦方程建立了微执行器动力方程,分析了边缘漏电场对静电力的影响,基于龙格-库塔算法将所有轴向载荷等效为轴向集中载荷,并分别仿真得到了变形与驱动电压、调节电压和轴向挤压量之间的关系,结果表明当驱动电压仅为16 V时,位移高达10.861μm,远大于目前传统横向加载单向变形微执行器的位移量.通过微型制造工艺加工了微执行器,利用高频信号采集了横向极板间的电压变化量,验证了仿真结果.     

多尺度模拟研究纳米凸体几何形貌对初始塑性的影响

研究金属表面微凸体的力学行为对深入理解摩擦、磨损和设计微纳米机电器件有很大帮助.采用准连续方法探索了纳米压痕作用在薄膜(001)表面的纳米微凸体几何形貌对铝和铜薄膜初始塑性的影响规律.结果显示,相较于平坦表面,微凸体的存在显著地降低了薄膜的屈服应力.矩形微凸体横纵比对屈服应力的影响不大.随着底角α的增大,梯形微凸体的屈服应力呈现降低的趋势,尤其是α＞54.7°.同时,在纳米尺度限制全位错形成的条件下,铝中可能容易形成挛晶结构.     

介电型电活性聚合物圆柱形驱动器侧向特性的研究

电活性聚合物（EAP）在实际生活中有着广泛的应用,介电型EAP圆柱形驱动器作为其典型应用之一,其输出的侧向偏转力和侧向弯曲角度受到介电型EAP膜拉伸面积比例、介电型EAP膜卷绕层数和柔性电极涂抹面积比例的影响,需要深入研究来确定其作用规律。针对这些影响因素对介电型EAP圆柱形驱动器输出的侧向性能的影响,设计制作了试验测试装置,通过控制变量试验测得了大量试验数据;分析处理试验数据,初步得出了影响因素的作用规律。结果表明：介电型EAP圆柱形驱动器输出的侧向偏转力和侧向弯曲角度都会受到介电型EAP膜拉伸面积比例、介电型EAP膜卷绕层数和柔性电极涂抹面积比例的影响,这些因素对其输出的侧向性能产生不同的作用结果。     

Domains in CoCr investigated by neutron depolarization

Polarized neutrons (λ = 0.47 nm) are transmitted through RF and magnetron sputtered CoCr films (0.3-5 μm thick) with the polarization vector in the plane or perpendicular to the plane of the film. In the former case we can deduce from the depolarization the effective height heffof the domains and from the angular dependence of the depolarization the section width δ (which is proportional to the domain width) in the remanent states after perpendicular and after in-plane saturation. As expected, heffappears to be larger after perpendicular saturation and for a film thickness h ∼ 400 nm, heffapproaches h. This is attributed to the disappearance of reversed spike domains in the thinnest films. The lower hefffound in magnetron films with a lower surface/bulk coercivity ratio is also consistent with spike domain theory. The section width δ is found to he proportional to hx with x depending on the preparation or magnetic history of the film between 0.6 and 0.8. For magnetron films δ is ∼ 1.5 as large as in RF films of equal thickness, in qualitative agreement only with the fact that K1is twice as large as for RF films.     

Thickness dependence of electrical properties of PZT films deposited on metal substrates by laser-assisted aerosol deposition

Dependence of electrical properties-dielectric, ferroelectric, and piezoelectric properties-on film thickness was studied for lead-zirconate-titanate (PZT) thick films directly deposited onto stainless-steel (SUS) substrates in actuator devices by using a carbon dioxide (CO₂), laser-assisted aerosol deposition technique. Optical spectroscopic analysis data and laser irradiation experiments revealed that absorption at a given wavelength by the film increased with increasing film thickness. Dielectric constant epsiv, remanent polarization value P_r, and coercive field strength E_c of PZT films directly deposited onto a SUS-based piezoelectric actuator substrate annealed by CO₂ laser irradiation at 850degC improved with increasing film thickness, and for films thicker than 25 mum, e > 800, Pr > 40 muC/cm², and E_c < 45 kV/cm. In contrast, the displacement of the SUS-based actuator with the laser-annealed PZT thick film decreased with increasing film thickness.