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。     

无缝微透镜阵列LED匀光膜研究

本文研究不同孔径无缝微透镜阵列膜LED光线扩散的影响,分析了不同厚度和直径的三角形、四边形和六边形微透镜阵列膜的扩散效果。设计了一种复合曲面微透镜阵列,利用光线追迹方法对其进行模拟,分析微透镜阵列对LED光源发出光线扩散性能的影响。     

193nm准分子激光器激光整形微透镜阵列压缩模塑成型工艺参数研究

为了实现193 nm准分子激光器激光整形及均匀化,制作一种微透镜阵列光学元件。本文采用L_93~3多因子正交方法进行实验,获得3因子3水平下压缩模塑成型的微透镜阵列。通过Taylor Hobson轮廓仪测量微透镜阵列形状误差,并采用极差分析方法分析模具温度、保压压力、冷却时间3种工艺参数对形状误差的影响程度,确定微透镜阵列光学元件的最优工艺参数组合。结果表明:当模具温度为230℃,保压压力为120 MPa,冷却时间为30 s时,微透镜的形状误差最好,值为0.5276μm,满足193 nm准分子激光器激光整形及均匀化对微透镜阵列形状误差小、精度高等要求。     

基于微纳米压印的微透镜阵列光学膜制造研究

目的 实现裸眼3D显示效果的承印基材是微透镜阵列光学膜,本文旨在研究制造微透镜阵列光学膜的方法及在制造过程中的影响因素。方法 采用卷对卷的UV-LED光固化微纳米压印工艺,通过定制化的微纳米压印模具,规模化制造正六角形孔径、蜂窝排布的微透镜阵列光学膜。结果 文中所用的PET膜表面粗糙度均方差约为0.083 μm,可见光波段的透光率为90%~93%,具有良好的表面平整度和较高的透光率,有利于微透镜阵列的成型制造和光学膜优良光学性能的呈现;UV-LED紫外压印光刻胶具有较低的黏度(250 Pa.s,25 ℃)、良好的界面性能(接触角为93°)和较小的固化体积收缩率(3.5%),有利于光刻胶对模具凹槽的填充及微透镜阵列的成型和脱模。对于微纳米压印制造过程,要选择合适的压印力,既要确保光刻胶能够充分地填充模具凹槽,又要避免微透镜阵列的结构受挤压变形而导致损坏模具。当压印速度控制在5~7 m/min时,微透镜阵列的复型精度较高且成型质量较为稳定,不会出现气泡缺陷和拉断缺陷。结论 卷对卷的UV-LED光固化微纳米压印工艺是一种制造微透镜阵列光学膜行之有效的方法。     

微透镜阵列超精密切削正弦过渡路径优化设计

微透镜阵列由于具有质量轻、结构小、视场大、分辨率高等优点,被广泛应用于光学领域.微注塑成型是实现其低成本批量生产的主要方法.如何高效、高精度、低成本加工模芯一直是研究的重点与难点.本文在传统微透镜阵列加工路径基础上,提出了一种正弦过渡加工路径,并对其过渡正弦的振幅和波长进行了分析,该方法有效避免了传统加工路径的不连续与突变问题.进行了正弦过渡路径优化设计和实际对比加工实验,实验结果表明该路径优化方法能有效地消除加工表面纹理,提高表面质量和加工效率.     

测量复合材料残余应力场的新方法

本文建立了一维表面光栅衍射光强分布与表面应变之间的理论关系,再利用弹性理论,即可求出材料中的残余应力,从而开拓了残余应力的测试方法;在测试技术方面本方法是在试样表面制作一维表面光栅,在激光束的照射下,形成一列清晰的衍射光斑,当试样背面剥层释放残余应力而发生形变时,引起表面光栅栅距d的变化,反映为放大了一列衍射光斑间距的变化,用电荷耦合器件将光信息快速地转换为电信号,以及A/D转换和微机控制的光信息处理系统,可高精度(m)、快速(s)地测试表面应变和残余应力的定量结果,这是一种测试分析表面应变和残余应力及其之间关系的新方法.      

采用组合透镜阵列准直半导体激光器线阵

为了满足半导体激光器线阵的远距离应用要求,需要对激光束进行准直处理.提出了一种由垂直双半圆柱透镜组合阵列构成的准直器,采用光线追迹的方法推导了激光束通过准直器的传输方程,分析了光线出射角与透镜阵列参数之间的关系,得出了准直器的最优设计参数,然后在zemax-EE非序列模式下仿真了此准直器的三维效果图以及探测器成像效果,得到的激光光斑接近于矩形,非相干照度集中在中央区域,并且经过准直器后的发散角大约为3 mrad.设计的准直透镜可以同时压缩快慢轴的激光束发散角,制作简单,安装方便.     

透镜阵列光刻法消差原理分析

透镜阵列光刻法用一个柱面阵列透镜代替常规光刻法中的柱面透镜形成光程差,将由衍射所引起的瞬变图形错开,消除由于光刻模板与被刻光栅之间因间隙引起的衍射误差。用光学传递函数方法说明了透镜阵列消除光刻中衍射误差的原理。实验表明透镜阵列光刻法,可以较好的消除衍射误差,研制出高质量的光栅。     

测量高功率激光束衍射光斑阵列位置的图象处理方法

介绍了测量高功率激光束射光斑阵列的各光斑中心位置的计算机图象处理方法。讨论了ＴＩＦＦ图象格式的全用技巧，利用灰度级确定各衍射光斑光强中心以及去除噪声光点的计算机处理方法，用计算机软件实现了常规Ｈａｒｔｍａｎｎ－Ｓｈａｃｋ传感器中子透镜阵列的子光束聚焦过程。     

微透镜列阵衍射效应所致的串扰

本文分析了微透镜列阵衍射效应的影响因素,推导出了微透镜焦平面上光强分布的解析表达式,对菲涅尔数评价衍射效应的物理含义给予了合理的解释.并利用ZEMAX软件对微透镜列阵进行仿真,基于惠更斯子波直接积分的算法计算得到了微透镜列阵焦平面上的光场强度分布.通过比较不同条件下所得到的计算结果,验证了以菲涅尔数作为微透镜列阵衍射效应评价依据的的合理性,同时验证了以菲涅尔数判断焦斑间串扰的可行性.     

Tunable liquid crystal microlens array using hole patterned electrode structure with ultrathin glass slab

A configuration of hole patterned electrode liquid crystal microlens array with an ultrathin glass slab was fabricated. To reduce the fringing electric field effect and avoid the occurrence of disclination lines, an ultrathin glass slab was introduced between the patterned electrode and liquid crystal layer. The glass slab thickness played an important role in effecting the optical performance of the liquid crystal microlens array. An optimum thickness of 30 μm was selected employing numerical simulation method. Using this method, we demonstrated a microlens array that greatly improved the phase profile and focus power. The dynamic focal range of the liquid crystal microlens array may extend from <1.2 mm to >8 mm and the minimum diameter of the focus spot could be as small as 15 μm.     

Replication of Microlens Arrays by Gas-Assisted Hot Embossing

This article reports an effective method for mass-production of 300 × 300 microlens arrays. A microlens array master is formed by imprint lithography and photo-resist reflow at room temperature. The electroforming is then applied to fabricating the Ni mold from the master, followed by the gas-assisted hot embossing to replicate the microlens arrays. The isotropic gas pressure on the plastic film against the Ni mold produces plastic microlens array of high quality and uniformity. The effects of processing parameters including the processing temperature, pressure, and time on the replication quality of microlens arrays were investigated. The experimental results show that the filling of molded microlens significantly increases as the processing temperature and pressure increase. Under the condition of 180°C, 3.9 MPa for gas pressure, and 90 seconds processing time, the arrays of polycarbonate microlens of diameter 150 µm and pitch 200 µm have been successfully replicated. The deviation of replicated microlens from the mold is less than 0.25%. Compared with the conventional hot embossing process, the new replication method offers more uniform embossing pressure distribution. The great potential for replicating microlens array on large plastic films with high productivity and low cost was demonstrated.     

Multipoint diffraction strain sensor with variable sensitivity

In our earlier work, a multipoint diffraction strain sensor using a microlens array was developed for measurement of whole-field strains. The method is extended to a system with variable sensitivity and measurement range. In the present system, two collimated laser beams, 3 mm in diameter, symmetrically strike the grating attached to the specimen surface at prescribed angles. The diffracted wavefronts, magnified by a microscope objective, are sampled by a lenslet array with each microlens acting as an individual strain sensor. In-plane strain components over the full field can be measured by what is to our knowledge a new sensor with variable sensitivity by changing the distance from the microscope objective to the microlens array. Both a theoretical explanation and experimental verification are provided.     

Effective formation method for an aspherical microlens array based on an aperiodic moving mask during exposure

An aperiodic mask design method for fabricating a microlens array with an aspherical profile is proposed. The nonlinear relationship between exposure doses and lens profile is considered, and the select criteria of quantization interval and fabrication range of the method are given. The mask function of a quadrangle microlens array with a hyperboloid profile used in the infrared was constructed by using this method. The microlens array can be effectively fabricated during a one time exposure process using the mask. Reactive ion etching was carried out to transfer the structure into the substrate of germanium. The measurement results indicate that the roughness is less than 10 nm (pv), and the profile error is less than 40 nm (rms).     

Implementation of field lens arrays in beam-deflecting microlens array telescopes

Laterally displaceable microlens array telescopes allow for variable and fast beam deflection. The generation of spurious light usually leads to a reduction of transfer efficiency with increasing displacement. We present the introduction of an array of field lenses on the back side of a recollimating microlens array that results in a reduced deflection angle dependency of transfer efficiency. A paraxial matrix formalism is used to prove the theoretical elimination of spurious light by use of a field lens array. The fabrication of well-aligned double-sided lens arrays by UV replication is discussed. Measurements of transfer efficiency with and without the use of field lens arrays are compared with the results of numerical wave-optic simulations.     

Design and fabrication of a freeform microlens array for a compact large-field-of-view compound-eye camera

In this research, a unique freeform microlens array was designed and fabricated for a compact compound-eye camera to achieve a large field of view. This microlens array has a field of view of 48°×48°, with a thickness of only 1.6 mm. The freeform microlens array resides on a flat substrate, and thus can be directly mounted to a commercial 2D image sensor. Freeform surfaces were used to design the microlens profiles, thus allowing the microlenses to steer and focus incident rays simultaneously. The profiles of the freeform microlenses were represented using extended polynomials, the coefficients of which were optimized using ZEMAX. To reduce crosstalk among neighboring channels, a micro aperture array was machined using high-speed micromilling. The molded microlens array was assembled with the micro aperture array, an adjustable fixture, and a board-level image sensor to form a compact compound-eye camera system. The imaging tests using the compound-eye camera showed that the unique freeform microlens array was capable of forming proper images, as suggested by design. The measured field of view of ±23.5° also matches the initial design and is considerably larger compared with most similar camera designs using conventional microlens arrays. To achieve low manufacturing cost without sacrificing image quality, the freeform microlens array was fabricated using a combination of ultraprecision diamond broaching and a microinjection molding process.     

微透镜列阵与红外探测器列阵集成芯片的研究

在分析微透镜列阵光聚能原理的基础上,针对背照式256290铂硅红外焦平面探测器列阵 的结构参数,设计了衍射微透镜列阵,使入射光通过硅基底聚焦至探测器的各个光敏面上, 提高光能利用率从而增强探测能力。实验获得了微透镜列阵与红外焦平面集成芯片,并在热成像中取得了良好的结果。     

微透镜列阵成像光刻调焦方法

本文分析了离焦量对微透镜列阵成像光刻图形质量的影响,给出了系统离焦量的容差.同时提出了一种结构简单、可应用于微透镜列阵成像光刻系统调焦的新方法.并将基于该调焦方法的实验装置应用于微透镜列阵成像光刻系统,进行了光刻实验.实验表明,利用该方法时微透镜列阵成像光刻系统调焦,可得到接近微透镜列阵极限像质的光刻图形.     

基于微透镜阵的外腔谱组束系统光束质量分析

针对基于微透镜阵的光纤激光外腔谱组束系统的光束质量评价问题,利用高斯光束的传输变换理论,建立了评价谱组束激光光束质量的理论模型.通过数值模拟,详细分析了各相关参数对谱组束光束质量的影响,结果表明:在基于微透镜阵的谱组束系统中,离焦量、微透镜焦距及模场半径是影响谱组束激光光束质量的主要因素;阵列宽度对谱组束激光光束质量影...