紫外曝光机均匀照明系统的设计与研究

紫外曝光机是印刷线路板(PCB)制作工艺中的重要设备,PCB高密度、微细化的发展趋势,对曝光机光照均匀性,平行性的要求越来越高。为了找出可以更好满足市场需求的曝光机光学系统,运用非成像光学方法,对两种不同光学结构曝光机的光斑均匀性进行了对比分析。通过实验可以看出,在通光孔径较大的光学系统中,复眼透镜阵列和方棒对改善系统光照均匀性以及能量利用率的作用,在实验基础上对如何选择光学系统的匀光器件做了对比性阐述。     

绝对式光栅尺母尺刻划曝光系统

提出了基于数字微镜器件(DMD)的双曝光头总体结构,该结构可同时刻划母尺的周期和非周期两个光栅码道。单曝光头包含曝光光源、调焦光源、DMD和投影镜头四部分,曝光光源由激光器、准直镜组、二维微透镜阵列和场镜组成。本文利用光学软件TracePro设计该光源,实现了能量的平顶分布,在14mm×10mm的照明面上均匀性达到95%以上。利用光学软件Zemax设计了工作在双波段(曝光光源0.403～0.407μm和调焦光源0.525～0.535μm)的共焦投影镜头,采用了二向色镜和分光棱镜使其能在曝光的同时进行实时调焦,优化后的系统在曝光波段和调焦波段均达到衍射极限,最大畸变为0.009%。与传统的光栅尺刻划技术对比,设计的曝光系统具有工艺简单、制作速度快、精度高等优势,可用于长、超长计量光栅的制作。     

提高汽车音响液晶显示器亮度及亮度均一化的结构优化设计

液晶显示器的工作原理要求给液晶提供一个光源,液晶才能显示亮度.结合提高汽车液晶显示器的亮度及亮度均一化的设计要求.通过对液晶显示器的导光板的结构原理、光学作用原理分析,优化设计照明系统中的导光板微结构的形状和参数,通过计算机模拟分析,设计结构和参数达到了提高显示亮度和提高亮度均一化的设计要求,并制作出样品通过光学设备的检测证明其设计的合理性.     

LED在基于光纤传输的照明系统中的应用

为了实现将LED应用于基于光纤传输的照明系统中以替代传统光源,首先简要介绍了基于光纤传输照明系统的应用及组成,描述了LED应用于光纤传输照明系统设计的光学扩展量理论。根据光学扩展量理论分析了LED选型方法,总结了基于LED光纤传输照明系统的设计原则和要点。然后应用设计实例:基于红,绿和蓝三色LED合光的光纤照明模组,详述了设计过程,给出了测试数据。结果表明:LED可以应用于光纤传输照明系统中替代传统光源,市场前景广阔。     

深紫外光刻照明系统光束整形单元的设计

为了使曝光波长为193 nm的深紫外光刻系统能够制备曝光线宽为90 nm及以下节点的集成电路芯片,设计了采用环形照明模式且部分相干因子σ连续可调,能满足不同曝光线宽要求的光刻照明系统光束整形单元.首先,用几何光学定律和三角函数推导了轴锥镜移动距离与光束放大倍率之间的函数关系;根据对变倍凸轮的合理性和装调公差灵敏度的分析...     

中科院光电所研制出3米长光栅复制光刻机

近日,一种新型“3米长光栅复制光刻机”在中科院光电技术所研制成功。这是该所继成功研发URE-2000系列大面积曝光机后创新研发的一项新型精密光刻设备。该机在母尺和工件间抽真空,采用蝇眼透镜的i线均匀照明系统,结合气浮工件台一维运动而实现大行程的扫描、真空接触、i线曝光。其照明均匀性为±2％,光刻分辨力优于5微米,照明面功率密度50mW／cm^2,     

LED阵列式紫外固化光源光学系统设计

设计了一种新型的LED阵列式紫外固化光源系统,该系统主要包括多路可控恒流源,紫外LED空间阵列及光学系统等,其中紫外LED空间阵列结构提高了光源的辐照度和均匀性。在分析光源结构的基础上,对其光学系统进行了设计,给出了LED空间阵列光学系统的设计方法和设计实例,并利用Light Tools光学仿真软件对其进行了模拟。结果表明:采用该光学设计方法得到的空间阵列辐照系统,其紫外辐照度可达200 mW/cm²,辐照面上光强分布均匀稳定,能够满足紫外光固化过程对光源的指标要求。     

视觉检测系统中照明光源的研究

在视觉检测系统中,照明光源的好坏对系统最终的测量精度有很大的影响.本文首先推导了视觉检测系统的光强传递函数,然后对照明光源的光强、光照稳定性和均匀性等设计要点进行了分析,最后设计了能自适应调整光强的环形冷光源.为视觉检测系统的推广和使用提供必备的物质条件.     

PCB曝光机自动控制系统设计

根据Printed Circuit Board（简称PCB）在生产制造过程中的工艺流程要求,设计了基于PLC控制的曝光机自动控制系统,包括控制系统的方案、硬件配置以及PLC输入输出点的地址分配和软件控制程序。该系统很好地满足了企业生产制造需求,具有自动化程度高,可靠性好等特点,提高了曝光机的生产质量和效率。     

表面多点触摸系统照明设计

为有效解决表面多点触摸系统照明亮斑问题,介绍了一种用于摄像式表面多点触摸系统的照明装置设计过程与方法,从光源选择,反光面以及控制电路的设计等方面进行论述,并结合具体实例对设计结果进行验证。实验结果表明,采用这种设计方法可以较好的解决表面多点触摸系统照明均匀性问题,提高触摸系统的精度。     

曝光机的能量稳定性研究

分析了PCB行业曝光机的故障停机问题,指出可以通过监控照度的方法,监控曝光机的能量输出,达到稳定曝光机运行的目的.     

Optimization of resolution by FDTD analysis in aligner lithography

A mask aligner can transcribe a pattern from a photomask to an exposure substrate by Fresnel diffraction. A diffraction fringe, specific to Fresnel diffraction, appears on a light intensity distribution of the pattern (a diffraction pattern image), and the formation of the pseudo-pattern restricts the resolution performance. The diffraction fringe can be smoothened by expanding the spread of the illumination source, and thus, the pseudo diffraction can be attenuated. However, this also causes a change in light intensity at the pattern edge to be attenuated, and the error of pattern line width to process change becomes large. Since edge diffraction patterns can be calculated by finite difference time domain (FDTD) analysis, the size of light source providing optimum resolution can be predicted by calculating and comparing pattern images corresponding to the size of the light source using this analysis. Therefore, by introducing an illumination optical system that can arbitrarily set the size of a light source to a predicted value, optimum resolution can be obtained without prior trial exposure. This study shows that the resolution of an aligner can be optimized by prior prediction, by introducing a multiple smoothing optical system that has been developed as an illumination system. This system realizes uniform illumination distribution on both a pupil plane and photomask plane and has an adjustable aperture mechanism that, by combining it with FDTD analysis, can arbitrarily set the size of the light source.     

CCD图像灰度与照度的转换标定方法

本文提出了一种基于CCD摄像机利用图像灰度获得实际照度的新方法,该方法适用于摄像机的任意曝光和增益参数,且考虑了摄像机安装位置和角度对测量的影响。CCD摄像机照度测量法的实际应用主要涉及两个过程:一是标定过程,即应用CCD摄像机进行照度测量前,标定CCD图像灰度与照度之间的转换参数和转换模型;二是照度测量过程,即通过CCD摄像机拍摄图像,将图像灰度代入已定的转换模型,获得测量对象的照度值。其中,灰度与照度转换模型的标定是利用CCD摄像机实现照度测量的基础和关键,文中主要讨论了该模型的推导过程以及标定方法。具体为:首先通过理论推导获得图像灰度与CCD传感器感应的相对辐照度的关系,然后借助以均匀光源搭建的实验系统标定CCD传感器相对辐照度与物面实际照度之间的关系,进而获得图像灰度与物面实际照度的转换关系。在转换过程中讨论了曝光时间、增益以及CCD相机与照度测量点之间的距离和角度对转换模型的影响,为CCD摄像机照度测量法的实际应用奠定了基础。实验结果表明本测量及标定方法适用于摄像机任意曝光和增益条件,经过本方法标定后,应用CCD摄像机进行照度测量,测量结果的相对误差在4.5%以内。     

A genetic algorithm to optimise the component placement process in PCB assembly

In printed circuit board (PCB) assembly, the efficiency of the component placement process is dependent on two interrelated issues: the sequence of component placement, that is, the component sequencing problem, and the assignment of component types to feeders of the placement machine, that is, the feeder arrangement problem. In cases where some components with the same type are assigned to more than one feeder, the component retrieval problem should also be considered. Due to their inseparable relationship, a hybrid genetic algorithm is adopted to solve these three problems simultaneously for a type of PCB placement machines called the sequential pick-and-place (PAP) machine in this paper. The objective is to minimise the total distance travelled by the placement head for assembling all components on a PCB. Besides, the algorithm is compared with the methods proposed by other researchers in order to examine its effectiveness and efficiency.     

Component Partitioning Under Demand and Capacity Uncertainty in Printed Circuit Board Assembly

This paper considers the problem of configuring a printed circuit board (PCB) assembly line experiencing uncertainty in demand and capacity. The PCB assembly process involves a single line of automatic placement machines, a variety of board types, and a number of component types. The line is set up only once, at the beginning of a production cycle, to eliminate setups between board types. Using this strategy, the line therefore can assemble all different types of PCBs without feeder changes. The problem then becomes to partition component types to the different machines in the hope of processing all boards quickly with a good workload balance. In this paper, the board demands and machine breakdowns are random but follow some probability distribution, which can be predicted from past observations of the system. We formulate this problem as a stochastic mixed-integer programming formulation with the objective of minimizing the expected makespan for assembling all PCBs during a production cycle. The results obtained indicate significant improvement over the existing methods. We hope that this research will provide more PCB assembly facilities with models and techniques to hedge against variable forecasts and capacity plans     

Mass production of 3-D microstructures using projection microstereolithography

Microstereolithography (MSL) technology is derived from the conventional stereolithography process and can meet the demands for fabricating complex 3-D microstructures with high resolution. This technology can be divided into scanning and projection methods, which have different levels of precision and fabrication speeds. Scanning MSL fabricates very fine 3-D microstructures by controlling the position of the laser spot on the resin surface. Projection MSL quickly fabricates one layer with one exposure using a mask. In this paper, we propose a projection MSL system with uniform illumination and image formation based on optical design for fabricating microstructure arrays. This system can realize mass production of 3-D microstructures in the meso-range, which falls between micro-and macro-ranges, with a resolution of a few microns. Microstructure arrays were fabricated to verify the performance of the proposed system.     

在线图像可视铁谱成像系统的像面照度均匀性

为了定量评价在线图像可视铁谱(OLVF)成像系统的像面照度均匀性,建立了一种像面照度模型。以像方参数及放大倍率表征物方视场,将物方视场区域离散化,采用朗伯余弦理论建立入瞳模式的像面照度模型,实现了像面照度的计算与均匀性评价。利用Matlab进行了物面照度仿真分析,确定了OLVF成像系统环形阵列光源的发光二极管(LED)数量,基于像面照度分析确定了最佳成像焦距和放大倍率。计算了油腔通油情况下成像系统中的光能量损耗以及磨粒沉积面的照度分布,建立了油液吸光系数与CCD像面轴上像点照度的关系。结果显示:LED发光强度已知时,仿真计算的像面不均匀度约为5.60%,实际测试的像面不均匀度为8%~9%,满足不均匀度≤10%的要求。开展了磨粒铁谱图像采集实验,结果表明:图像中磨粒清晰可辨,便于图像分割与视觉特征提取。提出的模型可定量描述OLVF成像系统的像面照度,可作为优化系统结构,提高系统成像性能的依据。     

PCB钻铣机CAD/CAM集成数控系统的设计与开发

介绍PCB钻铣机CAD/CAM集成数控系统的设计与开发的若干关键技术及其实现的方法。该系统主要解决印刷线路板加工中的图形设计、前/后置处理、路径优化和钻铣机数控系统等实用问题,目前已成功应用于多家印刷线路板生产厂和钻铣机生产厂。     

基于数字图像处理的印刷电路板缺陷检测

针对传统PCB检测方法高成本、低效率问题,提出一种基于数字图像处理的PCB板自动光学检测方法,建立了将标准图像和待测图像进行对比的检测系统。针对PCB板生产过程中遇到的短路、断路、空洞、凸起、凹陷等缺陷,采用了求连通区域数、计算欧拉数、求缺陷区域面积等方法,来检测上述缺陷问题,并给出算法的全过程。经实验结果分析,该方法能准确地检测出待检测电路板上存在的缺陷,达到了自动实时检测的目的。