高透光率聚光镜用菲涅耳透镜的计算

从物镜和光源的工作移动范围出发，提出计算双透镜聚光镜菲涅耳透镜的方法，这种方法能使断面的各参量达到最佳，从而可以提高整个放大率范围的光透过率，并减少来自聚光镜的散射光。     

菲涅耳透镜对平行光的成像特性分析

利用光线追迹与实验的方法 ,对菲涅耳透镜在平行光照明时的成像特性进行了分析。给出了在各种角度入射情况下的最佳像点位置及像点弥散斑大小 ,通过对结果进行分析 ,得出了最佳像面曲线及其特征与参数。并讨论了它们与菲涅耳透镜参数的关系。     

沟槽变异对菲涅耳透镜光学效率的影响

菲涅耳透镜以其良好的成像功能和很高的光学效率,广泛应用于教育投影仪、背投电视等大型成像设备。然而,出射面环形沟槽轨迹的不连续性给菲涅耳透镜的加工带来了诸多困难。为此,本文提出用连续阿基米德螺旋沟槽代替传统的同心环形沟槽,并从光学效率方面对它们进行了比较,计算结果验证了用螺旋沟槽代替同心环带沟槽的可行性,为螺旋沟槽型菲涅耳透镜的设计和制造提供了理论依据。     

对准误差对菲涅耳透镜衍射效率的影响

基于标量衍射理论,在傅立叶光学的基础上,首先得出存在对准误差情况下4台阶菲涅耳透镜衍射效率的解析式;并以4台阶、8台阶、16台阶菲涅耳透镜为例,系统分析对准误差对衍射效率的影响并进行计算机模拟研究.模拟计算结果对正在进行的16台阶菲涅耳透镜制作工作提供了理论指导.     

菲涅耳微透镜芯模表面形貌的检测及加工误差分析

采用扫描白光干涉法对菲涅耳微透镜芯模表面浮雕结构进行了检测,并对元件表面微观形貌进行了三维重建.根据其表面形貌数据,引入幅度参数表征法,分别计算出横向线宽误差以及样品的系统刻蚀深度误差和随机刻蚀深度误差等纵向加工偏差.通过表面高度分布的偏斜度、表面高度分布的峭度等参数获得了有关微芯模表面误差和缺陷的量化信息.实验研究表明,扫描白光干涉法能精确定量化表征微芯模表面形貌特征,这对探索适用于新型微光学器件表面三维形貌误差的无损检测评价方法具有实际意义.     

蜂窝式阵列菲涅尔透镜的配光设计

单元结构、阵列排布和偏转控制是阵列菲涅尔透镜的三个重要因素。单元结构采用了棱镜加菲涅尔透镜结构,排布方式引入蜂窝式阵列,构成蜂窝式阵列菲涅尔透镜。该透镜可以将准直光源发出的光线投射到1m远、直径为30mm的圆形区域内并形成特定图形。通过调整菲涅尔透镜的各个独立环带的倾角,以及每个菲涅尔透镜的背侧光面倾角的优化,实现了一款蜂窝式阵列菲涅尔透镜的光学设计。通过光学仿真分析,结果表明该设计方法灵活可靠,光线控制效果良好,具有实现图像级配光的能力。     

菲涅耳-夫琅和费衍射区的过渡判据

区分菲涅耳和夫琅和费衍射是光学中一个基本且又十分有意义的问题。然而从菲涅耳衍射到夫琅和费衍射的过渡条件判别,多数文献是通过实验、或者数值计算和模拟仿真给出结论的。基于标量衍射理论,通过数学分析,得到了从菲涅尔衍射过渡到夫琅和费衍射的判别条件(即菲涅耳数的值F=0.203),其结果和一般文献(F=0.223)相一致。     

基于菲涅尔透镜的室内LED射灯配光设计

为了将LED发出的光均匀投射到3m远直径为1m的圆形区域内,设计了一种LED(发光二极管)射灯。采用菲涅尔透镜对射灯进行二次光学配光设计,并通过调整菲涅尔透镜的各个独立环带的倾角来优化投射光的分布。文中对菲涅尔透镜的投光效果、安全性和加工误差等方面进行了考察,结果表明设计是安全的、可靠的并具有良好的投光效果。     

菲涅尔透镜光路的解析计算

讨论了菲涅尔透镜光路的解析计算,并提出修正误差和提高计算精度的方法。     

基于混合镜组模型的变焦镜头设计

为了优化变焦镜头的设计过程,本文提出了基于混合镜组模型的变焦镜头设计方法,包括近轴设计,镜组模型确定以及基于混合镜组模型的像差设计。近轴设计阶段采用了高斯括号和矩阵光学,可以很方便地构建镜组间隔和镜组焦距之间的关系。镜组模型确定阶段是根据现有镜头专利训练了一个镜组分类模型,它可以根据镜组近轴数据将镜组分为薄透镜模型或者厚透镜模型。像差设计阶段综合了薄镜组模型像差设计和厚镜组模型像差设计。镜组分类模型成功地将80%以上的镜组进行了分类。最后采用基于混合镜组模型设计方法设计了一个物方远心的变焦镜头。结果表明,该镜头具有良好的设计初值,基于混合镜组模型的变焦镜头设计方法能减少像差变量数量,准确、方便地完成像差设计。     

Miniaturized TIR Fresnel lens for miniature optical LED applications

Light-emitting diodes (LEDs) have been investigated to expand their application to very thin electronic devices, including various optical components in a single device. In such applications, the collimation of light produced by LEDs using a conventional Fresnel lens can be bent at angles greater than 45°, whereas most LEDs radiate at solid angles greater than 60°. This paper describes a miniaturized total internal reflection (TIR) Fresnel lens for such miniature optical LED applications. The proposed lens reduces the solid angle of a LED from 60° to 12°, and was designed to have a thickness of less than 1 mm with eleven facets on a single side. The overall geometry of the TIR lens was calculated numerically using Matlab, and the central hyperboloid was designed using Code V.     

Profile evaluation of radial Fresnel lens directly machined on roller molds by rotating-tool diamond turning

In Roll-to-Roll manufacturing of high-quality optical Fresnel lens films, a high-precision roller mold with super-fine surface quality is essential to precisely transfer the functional microstructures from the periphery roller surface onto the flexible substrate. Unfortunately, direct diamond turning of deep circular grooves on the periphery surface of a roller mold was considered infeasible. Recently, the team has developed a novel 4-axis interactive tool-workpiece motion, Rotating-tool diamond turning (RDT), as a solution to overcome this challenge. Experiments were conducted to justify the capability of the proposed RDT process by directly machining a radial Fresnel lens on a brass roller mold, but without precise 3D profile evaluation of the lens on the roller surface. On-machine measurement of the machined lens structures using 3D touch probe is not applicable because the diameter of the probe is relatively large to penetrate into steep grooves of the Fresnel lens. On the other hand, off-machine measurement using stylus profilometer will introduce inevitable alignment errors during the measurement and lead to mismatched machining and measurement coordinates, making it difficult to evaluate the 3D lens profile generated by the RDT process eventually. In this study, a compensation and comparison algorithm is presented to precisely evaluate the form error between the machined and designed features in a three dimensional manner. Alignment errors generated when positioning the roller mold on the stylus profilometer are investigated and quantified through analyzing the characteristics of this unique micro structure with Fresnel lens wrapped on the roller periphery. As a conclusion, the machined lens structure is compensated and restored to compare with the designed profile, and the form error is obtained with the sources of errors analyzed. Such profile compensation and comparison method can be applied in other measurement and characterization studies on evaluation of complex optical structures patterned on roller molds for Roll-to-Roll manufacturing of advanced functional films.     

An automated Guilloche machining technique for the fabrication of polygonal Fresnel lens array

Fresnel lenses are gaining wider applications in optoelectronics and photonic devices. They have been evolved into arrays of individual elements with better performance and better capabilities. These arrays may also be realized with individual elements having polygonal shapes such as rectangular, hexagonal, etc to achieve a high fill factor. Due to the fact that the polygonal Fresnel lens arrays are not rotationally symmetrical, they are manufactured by using expensive lithography techniques or time consuming method of having multiple molds assembled together. This paper presents an automated 4-axis ultraprecision machining technique for manufacturing an array of hexagonal Fresnel lenses. In the proposed method, a diamond tool moves as a fixed point on a circle rolling inside a fixed circle which is analogous to a Guilloche machine. The proposed automated machining technique has been experimentally verified through successful manufacturing hexagonal Fresnel lens array in a single process, without having separated sections assembled as a single master mold. From the results, an excellent surface finish and good profile accuracy are also achieved. The developed automated Guilloche machining technique also paves the way for the promising challenges to remove manufacturing barriers of machining freeform surfaces with complex curvatures.     

同轴双光束调制热透镜的理论研究

利用菲涅耳衍射理论提出了一种同轴双光束调制热透镜的理论模型,给出了探测面的热透镜信号表达式。计算了同轴双光束调制热透镜信号的横向分布,并分别讨论了激励光和探测光腰斑大小、样品位置和探测距离对信号的影响。     

大直径菲涅尔透镜模具加工工艺的模拟实验研究

通过大量实验,分析总结了主轴转速、进给量和切削速度对大直径菲涅尔透镜模具加工过程动态平稳性的影响规律;当切削速度Vc≥120 m/min,进给量f=1～1.5 μm/r时,形成带状切屑,容易断屑,工件一刀具相对振动幅值小,切削过程连续平稳,加工表面质量高.实验结果将为大直径菲涅尔透镜模具的实际生产提供重要依据.