菲涅耳透镜的通光分析及设计方法探讨

研究了菲涅耳透镜成像质量差的原因,提出一种改进的方法,即改善轴外点的成像质量以增大菲涅耳透镜的视场。分析了三种常用的设计菲涅耳透镜的方法,用光学设计软件Zem ax模拟设计结果,对三种设计方法进行比较。得出结论:像面为曲面时可校正场曲;基面和底面为曲面的菲涅耳透镜与平面型菲涅尔透镜相比彗差较小。     

大直径菲涅尔透镜模具加工发展现状及展望

大直径菲涅尔透镜广泛应用于太阳能电站、背投显示等领域,但其模具加工制造难度大。针对大直径菲涅尔透镜模具加工设备及加工工艺的发展状况进行了深入的分析研究,总结了大直径菲涅尔透镜模具加工的研究现状,展望了其未来的发展方向。     

大直径菲涅尔透镜模具加工发展现状及展望

针对大直径菲涅尔透镜模具加工设备及加工工艺的发展状况进行了深入的分析研究,总结了大直径菲涅尔透镜模具加工的研究现状,展望了其未来的发展方向。     

基于菲涅尔透镜聚热器的太阳追踪系统设计

太阳光线经过聚焦菲涅尔透镜折射汇聚到焦点处,将太阳能转变为热能加以利用,为确保焦点温度恒定且位置相对固定,现设计了一种南北方向倾斜布置,东西方向自动追踪的太阳追踪系统,主要设计包括:支架安装位置及结构设计、追踪传感单元设计、控制电路设计和控制策略设计,该太阳追踪系统可保证平面点聚焦菲涅尔透镜能较好地进行太阳追踪。     

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。     

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。     

面向CPV的聚光透镜制造装备设计技术研究

太阳能光伏发电作为太阳能利用中最具发展前景的技术已被广泛应用,其中由聚光透镜构成聚光器是光学系统中的关键部件,从而开展面向CPV的聚光透镜制造装备设计是实现太阳能光伏发电的基础。为此从复杂微结构大口径光学元件(菲涅尔透镜)结构及其表面微结构几何特征尺寸,分析得到超精密加工机床的技术要求。通过对装备功能构架的设计,获得超精密立式车床的总体构成,再分别对装备中床身、导轨、主轴、刀架等进行分析,获得满足菲涅尔透镜加工精度要求的超精密加工机床。     

基于成像式照度探测的菲涅尔光学助降系统检测方法研究

为了解决菲涅尔光学助降系统(FLOLS)的检测问题,文中根据FLOLS检测应满足的技术指标,提出了一种基于成像式照度探测法的菲涅尔灯发光强度测量方案,并根据分析设计研制了成像式照度探测装置。通过试验,结果表明该装置可远距离对大口径、大发光角度的菲涅尔灯进行发光强度的探测,满足菲涅尔光学助降系统检测装置测量的要求。     

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.     

高分辨率X射线衍射光学元件

评述了BESSY研制的用于X射线聚焦的各种衍射光学元件。基于布拉格-菲涅耳光学元件,设计了高效高分辨率X射线聚焦和色散光学元件。描述了对长焦距布拉格-菲涅耳透镜与可变曲率半径反射镜组合所做的实验研究。用一块反射菲涅耳波带板作聚焦和色散光学元件进行了短脉冲X射线吸收谱(XAS)的测量。     

基于LED阵列光源的太阳模拟器

针对目前LED太阳模拟器辐照度低、光谱匹配性差等不足,提出一种由LED阵列光源,菲涅尔透镜、光学积分器、准直物镜组成的LED太阳模拟器。首先根据多光谱拟合理论,在400~1 100nm优选15种不同波段的LED光源,计算出光源所需功率,实现太阳光谱的精确匹配。其次优化设计了菲涅尔透镜、光学积分器以及准直物镜,校正了太阳模拟器的像差,提高了太阳模拟器的能量利用效率以及辐照均匀性,并利用LightTools软件对所设计的光学系统进行仿真分析。最后搭建了光学系统实验装置,测试结果表明:100mm×100mm内的辐照度达到1 376.3 W/m~2;拟合的太阳光谱匹配度达到AM1.5条件中的A级,辐照不均匀度为±1.73%,辐照不稳定度为±0.82%,综合性能指标达到太阳模拟器中的3A级水平。     

Optical design of a static solar concentrator using Fresnel lenses

We present an optical design for a static solar concentrator for a photovoltaic cell (SCPV). The concentrator consists of two Fresnel lenses, one concave and one convex. The SCPV was designed and optimized using ray-tracing computer simulations. The performance of the SCPV was demonstrated using two settings: static mode and periodic mode with passive bi-yearly angle adjustments. Even without an active tracking system, the SCPV achieved an average Concentration ratio (CR) in the range of 1.94-2.86. The CR was distributed non-uniformly throughout the year, and the value and season of the highest CR were different for the two settings. The optimal mode for SCPV use can be chosen by balancing specific preferences regarding the target season for peak performance, maximum average CR, and maintenance frequency.

     

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.     

红外菲涅尔透镜的注射超声辅助成型优化

为了提升聚合物红外菲涅尔透镜的光学性能,以其表面微沟槽的成型质量为目标,提出了一种高效的注射超声辅助成型方法,并对工艺参数进行了综合质量优化。首先分析了超声振动对聚合物的加热和加压效应,设计了一套一模两腔的对比试验模具;接着以红外菲涅尔透镜的调制传递函数MTF和齿形平均高度h为优化质量目标,设计了四步骤的多目标优化流程,通过试验设计、基于BP神经网络的质量目标与注射工艺参数关系建模、基于NSGA-Ⅱ的多目标优化和试验验证进行工艺参数的综合优化。实验结果表明:该多目标优化流程具有很高的精度,MTF和h的平均预测误差MPE分别为4.16%和3.32%;注射超声辅助成型的菲涅尔透镜微沟槽具有更高的复制质量,其齿沟槽平均高度h增加了15.6%,且h值的波动量随着h值的增大而增大,MTF值受齿高h均匀性的影响大于齿高h对其的影响。     

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.     

Fluorescent resolution target for super-resolution microscopy

We report methods of near‐field infrared microscopy with transient optically induced probes. The first technique – a transient aperture (TA) – uses photoinduced reflectivity in semiconductors to generate a relatively large transient mirror (TM) with a small aperture at its centre. We report the optical properties of the TM and TA and experiments performed on near‐field imaging with the TA. The second technique is based on solid immersion microscopy, in which high resolution is achieved when light is focused inside a solid with a high refractive index. By creating a transient Fresnel lens on the surface of a semiconductor wafer via photoinduction, we were able to form a solid immersion lens (SIL) for use as a near‐field probe. The use of transient probes eliminates the need for mechanical scanning of the lens or sample, and thus provides a much faster scanning rate and the possibility to work with soft and liquid objects.