光学非球面离子束加工模型及误差控制

摘要：通过对离子束加工系统的分析,给出了加工非球面光学元件的离子源子系统运动模型公式,并将驻留时间求解的反卷积过程转化为求解线性矩阵方程模型,便于进一步优化求解;对加工过程中不可避免的离子源定位误差过程进行了分析,指出其对最终面形精度的影响可归结为一个系数因子的控制上,并提出了综合考虑离子束材料去除函数和定位误差的方法来控制系数因子,降低对定位系统的苛刻精度要求,保证过程稳定的同时降低设备成本。     

Matrix based algorithm for ion-beam figuring of optical elements

An algorithm for solving the problem of local shape errors of optical surfaces correcting by a small-sized ion beam, based on the matrix representation is presented. The algorithm involves searching for points that rise relative to the average height on the surface, where exposure to an ion beam of a given shape will lead to a decrease in the RMS deviation of the surface shape from the calculated one. It is shown that the new approach makes it possible to significantly expand the range of spatial frequencies, in which the height of relief can be reduced using the given ion beam size, and provides better results than the method of minimizing the functional of convolution of the ion beam and the surface map. Moreover, the new approach does not lead to appearance of shape errors (concentric structure) defined by the ion beam size and scanning step. An experiment for minimizing of local surface shape errors based on an etching map calculated using new approach was done. Matrix algorithm allowed in one procedure to reduce surface shape errors for a concave spherical optical element made of fused silica with a diameter D = 100 mm and a radius of curvature R = −137.5 mm in the RMS by more than 3 times. The initial RMS was 4.5 nm, RMS after treatment is 1.36 nm.     

化学刻蚀的光学元件面形修复

采用化学加工方法对光学元器件进行面形加工,可以避免传统的抛光工艺带来的亚表面缺陷和表面污染。实验中利用Marangoni界面效应有效控制化学液的驻留时间和驻留面积,并通过数控系统实现编程控制加工,进行了面形修复实验,利用轮廓仪测量了加工前后的表面粗糙度。结果表明,采用拼接小去除量多次加工的方法,有效地降低了面形误差,面形值由1.32 λ(λ=632 nm)减少到0.66 λ,粗糙度基本维持不变。利用此实验装置使基片面形得到修复,避免了传统加工方式带来的亚表面缺陷等问题,有利于强激光系统的使用。     

离子束抛光高陡度离轴非球面的去除函数修正

研究了三轴离子束系统抛光大口径高陡度离轴非球面过程中镜面曲率变化对离子束抛光去除函数的影响.提出了利用修正矩阵修正各驻留点处的去除函数信息,进而实现对高陡度离轴非球面高精度抛光的方法.该方法通过对离轴非球面进行坐标转换来降低陡度变化对去除函数的影响;基于Sigmund溅射理论分析离子束抛光非球面材料的去除率,建立离子束抛光非球面去除函数模型,计算了材料去除率在非球面各驻留点处的变化.最后,根据投影原理计算在各驻留点处去除函数的半宽,得到以驻留点矩阵为基础的去除函数修正矩阵,从而掌握每一个驻留点处的去除函数信息,然后根据计算机控制光学表面成形(CCOS)原理解得加工驻留时间分布.选取口径为900mm×680mm,离轴量为350mm的离轴体育场型非球面镜进行了抛光实验,实验显示抛光后非球面镜面形精度的RMS值由32.041nm达到11.566nm,收敛率达2.77,对实际加工具有指导意义.     

光学镜面离子束加工材料去除效率

分析了离子束加工材料去除效率、不同材料之间的相对去除效率与工艺参数的关系。基于Sigmund溅射理论,建立表征去除效率的指标－法向去除率、体积去除率和溅射产额与束能、束流以及入射角度之间的关系模型。以石英、微晶和K4等为样件,实验分析了去除效率与工艺参数的关系,验证了模型的正确性。分析结果表明材料去除效率随束流线性增大;约与束能平方根呈线性关系;随着入射角度先缓慢增大,约在60~80°达到最大值,尔后迅速降为零。不同材料之间的相对去除效率与束流无关;与束能的关系较弱,可以忽略;随角度变化较为明显。     

Nano-abrasion machining of brittle materials and its application to corrective figuring

A method of ultraprecision abrasion machining named “Nano-abrasion machining” is proposed for optical finishing of brittle materials. The fundamental characteristics and its applicability for corrective figuring to improve form accuracy of optics of brittle materials are investigated. It is experimentally ascertained that the material removal rate and surface roughness are suitable for optical finishing. However, the cross-sectional profile of the machined spot that is dependent on the collision angle is a combination of V- and W-shape, which is unsuitable for the corrective figuring. Therefore, circular motion machining is introduced and a preferable profile with an axis-symmetric V-shape is realized. The machining method is applied to corrective figuring of optical glass of BK7. The NC program is generated with a computer program developed by modifying the scanning motion and the form accuracy is predicted. According to the simulation results, corrective figuring is performed. The flatness is improved from PV = 151 to 29 nm. From the experimental results, it is clarified that the nano-abrasion machining is applicable to corrective figuring of brittle materials.     

光学镜面离子束加工的材料去除效率

分析了离子束加工光学镜面的材料去除效率和不I司材料之间的相对去除效率与工艺参数的关系.基于Sigmund 溅射理论.建立了表征去除效率的指标一法向去除速率、体积去除速率和溅射产额与束能、束流以及入射角度之间的关系模型.以石英、微晶和K4玻璃等为样件,实验分析了去除效率与工艺参数的关系,验证了模型的正确性.分析结果表明,材料去除效率随束流线性增大,与束能平方根约呈线性关系;随着入射角度先缓慢增大,约在60～80°达到最大值.然后迅速降为0.不同材料之间的相对去除效率与束流无关;与束能的关系较弱,可以忽略;随角度变化较为明显.     

离子束螺旋扫描方式修正光学镜面方法

研究基于螺旋扫描方式的光学镜面离子束修正方法.根据离子束去除函数的特性,将螺旋扫描加工过程简化成线性过程并建立工艺过程模型,采用基于Bayesian原理的改进Richard-Lucy迭代法求解驻留时间.在分析驻留时间的连续速度实现基础上,给出螺旋路径参数的确定准则.建立螺旋扫描加工方式的工艺流程并进行试验验证研究.试验研究对φ100平面镜和φ200非球面镜修形加工得到了面形方均根误差均优于0.01λ.研究结果表明:极轴加工与普通的全口径加工一样是一种高效率、高确定性的加工方法,能够对镜面进行精确修形,同时可以节约加工成本.     

基于Bayesian原理的低陡度光学镜面面形误差离子束修正驻留时间算法

离子束修形是一种高效修除镜面误差的技术,驻留时间求解算法是此技术的关键问题之一。以光学镜面计算机控制成型原理为基础,建立基于Bayesian原理的平面镜面驻留时间算法,对数据边缘进行Gaussian延拓以消除边缘效应。分析驻留时间近似速度实现方式的实现误差与工艺参数的关系,通过在算法中引入附加光滑修正因子以提高驻留时间实现精度。在适当的路径规划下,将低陡度非球面修形过程近似用平面修形过程线性模型来描述,最终形成低陡度光学镜面面形误差离子束修正中驻留时间的快速近似算法。利用此算法对 100平面镜和 200球面镜进行修形加工,加工收敛率均可达9。研究结果表明：线性化近似模型是合理的,速度近似计算是可行的,基于Bayesian原理的低陡度非球面驻留时间求解算法是一种快速高效面形控制技术,可对镜面进行确定性精确修形。     

光学镜面离子束加工系统设计和分析

研究了离子束加工系统的后置算法和误差补偿等问题。基于DH矩阵法,建立了系统的运动学方程,分析了工艺中离子源和工件的安装误差以及离子源相对于工件的六项对刀误差对加工定位的影响,建立了误差模型。在求解运动学方程时引入纠补矩阵,以消除离子源确定性的安装偏差对切平面定位误差的显著影响。补偿后的误差分析表明：切平面误差模型对对刀和安装精度提出要求后,靶距误差和入射角度误差同时也受到了限制,对加工的影响可以忽略不计。     

Nano-slit probes for near-field optical microscopy fabricated by focused ion beams

The near-field probes described in this paper are based on metallized non-contact atomic force microscope cantilevers made of silicon. For application in high-resolution near-field optical/infrared microscopy, we use aperture probes with the aperture being fabricated by focused ion beams. This technique allows us to create apertures of sub-wavelength dimensions with different geometries. In this paper we present the use of slit-shaped apertures which show a polarization-dependent transmission efficiency and a lateral resolution of < 100 nm at a wavelength of 1064 nm. As a test sample to characterize the near-field probes we investigated gold/palladium structures, deposited on an ultrathin chromium sublayer on a silicon wafer, in constant-height mode.     

离子束抛光去除函数计算与抛光实验

由于传统的离子抛光工艺采用的确定去除函数的方法操作复杂且成本很高,本文提出了利用法拉第杯对离子束流空间分布进行测量、标定的方法,并计算得到不同离子源工作参数对应的去除函数.首先,基于离子束抛光材料去除原理,研究了离子束抛光过程中束流分布与能量对去除函数的影响,并提出简化的离子束抛光去除函数模型.然后,设计实验并得出离子束流空间分布与去除函数相关参数间的关系,计算得到了不同离子源工作参数产生的离子束流对应的去除函数.对硅和融石英玻璃的相关实验表明:利用法拉第杯扫描结果计算相同材料的去除函数的单位时间体积去除率与实际测量值误差小于2%.结合抛光实验,对Φ800mm碳化硅表面硅改性层平面镜进行抛光,得到的初始面形误差均方根(RMS)值为57.886nm,两次抛光后RMS值为11.837nm,收敛率达到4.89,满足精密光学加工对去除函数的确定性及精度的要求,并大大提升了确定去除函数的效率.     

快速运动模糊图像盲解卷积算法

针对快速运动形成的图像模糊,提出了一种运动模糊图像盲解卷积算法.首先,对被噪声污染的频谱图像进行脊波增强;然后,采用一种新的基于Radon变换的鲁棒算法来确定模糊核函数,该算法在小模糊长度和低信噪比的条件下仍能准确地估计模糊核参数;确定模糊核函数后,采用基于hyper-laplacian先验的快速非盲解卷积算法来恢复模糊图像.实验结果证明,与基于机器学习的R.Fergus的算法相比较,本文算法在获得相近效果的前提下,计算时间从近30 min下降到40 s左右.该算法对合成运动模糊图像和实际相机运动的自然模糊图像都具有较好的恢复效果.     

塑料光学元件制造

由于光学塑料具有许多杰出的优点 ,因而在照相机、光盘、投影镜头、眼镜等方面获得了日益广泛的应用。塑料光学元件的关键制造技术是模具设计和制造、选择合适的注塑设备、最佳的工艺参数等。为了制作以光盘物镜为代表的高精度非球面塑料透镜 ,就应采用注射压缩工艺抑制变形的成形技术 ,辅之以考虑变形而补偿模具的成形技术。     

Atmospheric pressure ion sources

This review of atmospheric pressure ion sources discusses major developments that have occurred since 1991. Advances in the instrumentation and understanding of the key physical principles are the primary focus. Developments with electrospray and atmospheric pressure chemical ionization and variations encompassing adaptations for surface analysis, ambient air analysis, high throughput, and modification of the ionization mechanism are covered. An important and limiting consequence of atmospheric pressure chemical ionization, chemical noise, is discussed as is techniques being employed to ameliorate the problem. Ion transfer and transport from atmospheric pressure into deep vacuum is an area undergoing constant improvement and refinement so is given considerable consideration in this review. © 2009 Wiley Periodicals, Inc., Mass Spec Rev 28:870–897, 2009     

改进卡尔曼滤波的融合型锂离子电池SOC估计方法

荷电状态(SOC)估计对于锂离子电池充放电优化控制、任务规划、可靠性提升等均具有重要价值,针对广泛应用的卡尔曼滤波(KF)一类方法存在的参数设置无具体标准、模型性能随工况环境改变而适应性降低等问题,提出一种噪声方差可变卡尔曼滤波方法(VVKF)的SOC估计算法,该算法每次迭代时估计并设定最适应当前系统状态的的噪声方差,克服了KF噪声方差初值依靠人为经验设定而造成精度下降的问题,同时采用最小二乘支持向量机作为KF的量测方程,通过建立样本库的方式克服电池型号以及工况改变对SOC估计精度的影响。采用马里兰大学CACLE中心锂离子电池数据集的实验证明了VVKF较KF性能的提升以及SOC估计的有效性。     

Richardson-Lucy algorithm with total variation regularization for 3D confocal microscope deconvolution

Confocal laser scanning microscopy is a powerful and popular technique for 3D imaging of biological specimens. Although confocal microscopy images are much sharper than standard epifluorescence ones, they are still degraded by residual out-of-focus light and by Poisson noise due to photon-limited detection. Several deconvolution methods have been proposed to reduce these degradations, including the Richardson-Lucy iterative algorithm, which computes maximum likelihood estimation adapted to Poisson statistics. As this algorithm tends to amplify noise, regularization constraints based on some prior knowledge on the data have to be applied to stabilize the solution. Here, we propose to combine the Richardson-Lucy algorithm with a regularization constraint based on Total Variation, which suppresses unstable oscillations while preserving object edges. We show on simulated and real images that this constraint improves the deconvolution results as compared with the unregularized Richardson-Lucy algorithm, both visually and quantitatively.     

ITO thin films prepared by electron beam evaporation with End-Hall ion source assisted without heating to the substrate

1Introduction ITO(indiumoxidedopedwithtin)trans parentconductingfilmshaveuniqueopticaland electricalpropertiesofhightransmittanceinthe visibleregionandstrongreflectanceintheinfra redregionaswellastheexcellentconductivity.Forthesecharacteristics,ITOfilmsplayanim portantroleinthefieldofoptoelectronicde vices,suchastransparentelectrodeforelectro magneticinterference(EMI)shielding,electro chromicwindow[1],liquidcrystaldisplays(LCD)[2],andarchitecturalapplications.Ava rietyofthinfilmdepositiont…     

Scanning ion microprobe analysis of composite materials

Applications of scanning ion imaging with high lateral resolution in the microchemical investigation of metal – and ceramic-matrix composites are described. The technique, which combines a scanning ion microprobe with secondary ion mass spectrometry (SIMS), is ideally suited to the study of complex, multicomponent composite structures. Most elements can be detected with good sensitivity, enabling the determination of spatial distributions for major and minor elements. Analytical images obtained with this technique reveal unprecedented chemical information about interfacial segregation and interdiffusion phenomena. As examples, the characterization of both ceramic–matrix (Al borate–SiC) and metal–matrix (Ni alloy–Al₂O₃) composite materials is described.     

Quadrupole ion traps

The extraordinary story of the three‐dimensional radiofrequency quadrupole ion trap, accompanied by a seemingly unintelligible theoretical treatment, is told in some detail because of the quite considerable degree of commercial success that quadrupole technology has achieved. The quadrupole ion trap, often used in conjunction with a quadrupole mass filter, remained a laboratory curiosity until 1979 when, at the American Society for Mass Spectrometry Conference in Seattle, George Stafford, Jr., of Finnigan Corp., learned of the Masters' study of Allison Armitage of a combined quadrupole ion trap/quadrupole mass filter instrument for the observation of electron impact and chemical ionization mass spectra of simple compounds eluting from a gas chromatograph. Stafford developed subsequently the mass‐selective axial instability method for obtaining mass spectra from the quadrupole ion trap alone and, in 1983, Finnigan Corp. announced the first commercial quadrupole ion trap instrument as a detector for a gas chromatograph. In 1987, confinement of ions generated externally to the ion trap was demonstrated and, soon after, the new technique of electrospray ionization was shown to be compatible with the ion trap. © 2009 Wiley Periodicals, Inc., Mass Spec Rev 28:961–989, 2009