Chromatic aberration elimination for digital rear projection television L-type lens by genetic algorithms

Following the development of a digitalized image optics system, chromatic aberration has become increasingly important especially in lateral color aberration. For rear projection television L-type lens, chromatic aberration plays the significant role because it is easily seen when facing bright screen. Basically, the elimination of axial chromatic and lateral color aberration for an optical lens depends on the choice of optical glass. DLS (damped least squares), a Ray-tracing-based method, is limited, owing to its inability to identify an enhanced optical system configuration. Genetic algorithms were applied to so-called global optimization but unfortunately so far the results show little success. Additionally, L-type optics with aspherical surface might complicate optimization due to being nonlinear response during optimization. As an alternative, this research proposes a new feasible chromatic aberration optimization process by using algorithms involving theories of geometric optics in a lens, real encoding, multiple dynamic crossover and random gene mutation techniques. In this research, rear projection television lens with aspherical surface and L-type lens are mainly discussed. Results and conclusions show that attempts to eliminate difficult axial and lateral color aberration are successful.     

复消色差的短波红外望远物镜设计

分析计算了一些普通光学玻璃及晶体光学材料在0.9~2.5 μm短波红外段的色散特性.在远距型的物镜结构后组中采用的厚弯月镜能产生一定量的反向色差补偿前组中的二级光谱,所设计的物镜在焦距800 mm时的带孔径处最大色差0.13 mm.结果表明,采用氟化物玻璃与重火石玻璃的三片式组合在短波红外段具有较好的消色差能力.     

激光靶心冲击波观测镜折反式光学系统设计

设计了一种激光靶心冲击波观测镜的光学系统.用反射式光学系统代替折射式光学系统,解决了普通玻璃在200 nm端透过率较低的问题.反射镜不引入色差,有利于系统在200~800 nm谱段消色差.为消系统轴外像差,反射系统选型为对称式.反射镜全部采用球面镜,为消反射镜以及平板玻璃窗带入的球差,引入校正镜(材料JGS1),在满足要求的条件下,控制折射镜的厚度,使系统色差满足瑞利判据的色差允差,得到了良好的成像质量.     

Optimization of 350× optical zoom lens with diffractive optical element

Through researching and validating, a set of optical designs using a diffractive optical element (DOE) and optimization process has been derived in this paper. We put forward a set of theories to solve the numerous quality issues in imaging and applied it to an optical design. For an optical design to be successful, it must comply with the standards of the optical system. Optical designers must also take into consideration imaging quality, wherein the most influential aspects are chromatic aberration and monochromatic aberration. We complied with systemic standards such as effective focal length and total system length. Diffractive Optical Element, based on the theory of wave phase difference, takes advantage of negative Abbe number, which might significantly eliminate chromatic aberrations of optics. Following the advanced technology applied to micro lens and etching process, precisely made micro DOE element now is possible to be manufactured in a large number. A 350× zoom lens with DOE is demonstrated in the proposal. The results show that regardless of whether chromatic aberration is axial or longitudinal, issues concerning the optical lens's chromatic aberration could be significantly reduced.     

4k数字放映机广角放映镜头的设计

为满足4k电影的短距离放映需求,设计一款广角放映镜头,可适配于采用三芯片DMD技术的放映机,最大投射比可达0.75∶1,相对孔径为1/2.2,反远比为4.6∶1,在66 lp/mm的Nyquist频率处,MTF值为0.42,边缘视场MTF值为0.25。最大横向色差为3.7 m0.5 pixel,最大畸变为2.5%。分析了反远距形式的特点,给出了合理选型、分配光焦度和计算关键技术参数的方法,以及像差校正过程中应注意的问题。最终设计出了符合设计指标的具有高分辨率的广角放映镜头,该镜头结构简单、成本低。     

基于胶合棱镜的AOTF成像光谱仪横向色差校正

设计声光可调谐滤波器(AOTF)成像光谱仪时,ZEMAX等软件缺乏AOTF光学表面,导致光学设计困难,本文根据波矢量匹配原理,在ZEMAX中建立了基于声光衍射效应的AOTF自定义表面模型,实验表明该模型能够实现AOTF的衍射光精确追迹。在此基础上,针对传统方法校正AOTF横向色差时残差较大的问题,提出了基于胶合棱镜的高精度横向色差校正方法,结合AOTF自定义表面,完成了胶合棱镜的玻璃组合和顶角的自动优化。结果表明,文章提出的自定义表面和胶合棱镜色差校正相结合的方法大大方便了AOTF成像光谱仪的设计,能够将横向色差控制到0.000 3°,比以往方法提高了一个量级,有效抑制了光谱图像的漂移。     

Differential algebraic method for arbitrary-order chromatic aberration analysis of electrostatic lenses

In this paper, differential algebra is applied to calculate arbitrary high-order chromatic aberrations of electrostatic electron lenses. Expressions of differential algebraic form of high-order combined chromatic aberration coefficients are obtained and arbitrary-order chromatic aberrations can be calculated numerically. As an example, a typical Schiske's electrostatic lens has been studied. All the first- to third-order chromatic aberration coefficients of the lens have been calculated, and the pattern of the first-order chromatic aberration has been given as well.     

Single Telephoto Lens for Focus Error Detection with Astigmatic Method

An astigmatic method for focus error detection has been integrated into a singlet. The first convex and the second concave surfaces compose a telephoto system with a telephoto ratio of about 0.4. The first surface of the lens is rotationally symmetrical asphere and the second surface is a toric shape whose aspherical profiles correct spherical aberration. We implemented our optical design using a molded glass process. Its performance was confirmed using the optical head of a magneto-optical disk system.     

Diffractive-Refractive Achromatic Lens for Optical Disk System by Glass Molding

An erasable optical disk system requires an objective lens having minimum chromatic aberration. We estimated the chromatic aberration of a conventional refractive singlet. At shorter wavelengths, the focus shift of an objective lens exceeds its depth of focus. A diffractive-refractive hybrid lens can compensate chromatic aberration perfectly. Diffraction efficiency, however, decreases with the degree of compensation. We simulated the relationship between chromatic aberration and diffraction efficiency. Fabrication of designed lenses by glass molding was achieved, and the results showed excellent agreement with the simulation.     

透镜初级球差的横向剪切干涉条纹研究

利用玻璃平行平板构成简单的横向剪切干涉仪可以观察到单薄透镜形成的准直光束的剪切干涉条纹,由干涉条纹分布求出对应的几何像差和离焦量.用焦距为190 mm的单薄透镜做实验,实验结果与计算机模拟结果符合,说明可以从剪切干涉条纹的分布求出透镜的轴向调整误差和初级球差.     

宽光谱长焦距物镜的复消色差设计

介绍了以摄远型为初始结构的宽光谱长焦距折射式物镜的设计方法。对玻璃材料的选择进行了分析,并建立了能够分配三分离透镜组光焦度的复消色差方程组。通过理论计算和ZEMAX光学设计软件的优化,给出工作波长范围在0.4~0.9μm、焦距为400 mm、视场角为6.2°、相对孔径为1∶4的设计实例。设计结果表明,二级光谱得到了很好的校正,像质优良。     

梯度折射率棒透镜的色差估计

对梯度折射率(GRIN)棒透镜色差的影响因素进行了研究,在玻璃光学性质计算模型的基础上建立了梯度折射率棒透镜色差估计函数与基础玻璃性能、交换离子对性质和参与交换的离子数量之间的关系。对Na+/Li+,K+/Cs+和K+/Tl+交换制备的梯度折射率棒透镜的色差进行了计算,结果表明,GRIN棒透镜的色差评价函数主要取决于基础玻璃和交换离子的性质,而与参与交换的离子数量无关。     

内调焦摄远镜头的光学设计

提出了一种内调焦摄远镜头的光学设计方法。分析了其二级光谱特性 ,通过合理的选择玻璃材料校正了二级光谱色差。在光学结构上采用远距型结构以达到较小的远摄比。采用内调焦方式缩小了外形尺寸 ,简化了机械结构。通过实例说明了设计结果。内调焦摄远镜头的设计结果为 :焦距为 50 0mm ,相对孔径为 1∶4 .5 ,视场角为 5°,最近摄影距离为 5m ,调焦方式为内调焦 ,成像质量高于国家标准GB991 7 88所规定的J0 级镜头标准     

基于共心球透镜的多尺度广域高分辨率计算成像系统设计

针对实时广域高分辨率成像需求,充分利用具有对称结构的多层共心球透镜视场大且各轴外视场成像效果一致性好的特点,设计基于共心球透镜的多尺度广域高分辨率计算成像系统.该系统基于计算成像原理,通过构建像差优化函数获得光学系统设计参数,结合球形分布的次级相机阵列进行全局性优化,提高系统性能的同时有效简化光学设计过程、降低系统设计难度.系统稳定性测试结果表明,该成像系统的MTF(modulation transmission function)值在截止频率处接近衍射极限,弥散斑均方根恒小于探测器像元尺寸,整机实景实时成像效果良好,无视觉可见畸变.该系统不仅有效解决了传统成像中广域和高分辨率成像矛盾的问题,而且为计算光学成像系统设计奠定了一定研究基础.     

隐秘型CCD微摄像镜头光学设计

为了满足隐秘型ＣＣＤ摄像光学系统的广角视场、长工作距离、小空间尺寸、隐蔽性能好、成像质量优良等特殊要求。提出一种以同心透镜作为负组,置孔径光阑于镜头前方的新型反远摄结构。对其设计思想、像差特点进行了分析,并给出了ｆ′＝３６ｍｍ,２ω＝８０°,ｌＦ′／ｆ′＝１１的隐秘型ＣＣＤ微摄像镜头的像差和传函计算曲线     

透镜转像式军用瞄准镜物镜设计

为了满足瞄准镜体积小、重量轻的要求,需要物镜采用摄远型结构。分析了摄远型透镜转像式物镜的光学特性与像差特点,提出了摄远型镜组、正场镜和对称式转像镜组构成的结构型式。依据系统的成像特性,推导了光焦度分配和外形尺寸计算公式。采用光学设计软件Zemax设计了摄远型透镜转像式物镜,系统焦距为-100 mm,入瞳直径为25 mm,视场角为8,系统总长仅为99.92 mm。设计结果表明,采用该方法设计的瞄准镜物镜在40 lp/mm处各个视场的调制传递函数均在0.2以上,满足目视光学仪器的使用要求。     

折/衍混合单透镜在目镜中的应用研究

以传统凯涅尔目镜为基础，采用ZEMAX软件，设计了衍射面位于目镜系统中不同位置时的折／衍混合目镜系统，所有系统均仅采用最普遍的K9玻璃，设计结果与传统凯涅尔目镜的光学性能进行了分析和比较。结果表明折／衍混合目镜系统在校正目镜的像差，例如像散，垂轴色差、垂轴像差，轴向像差和轴向色差等方面优于传统的凯涅尔目镜，选择合适的衍射面位置，可以同时获得符合要求的畸变，衍射面的引入，极大地减小了系统的重量和尺寸。     

Theory of paraxial lateral aberrations of electrostatic imaging electrostatic electron optics based on asymptotic solutions and its verification

In imaging electron optics, study of geometrical lateral aberrations of third order and paraxial lateral aberrations of second order has traditionally been paid more attention to, but the existence of paraxial chromatic aberrations of third order and paraxial chromatic aberrations of magnification of third order was almost ignored, and the general form of paraxial lateral aberration has not been studied theoretically.In the present paper, the paraxial lateral aberrations expressed in general form have been derived emphatically on the basis of asymptotic solutions of paraxial equation. The relationship between the coefficients of asymptotic solutions has been investigated, which proves that the coefficients of asymptotic solutions are related each other. Through a bi-electrode electrostatic spherical concentric system model, two special solutions expressed by asymptotic solutions and accurate solutions in a bi-electrode electrostatic spherical concentric system have been deduced, and the paraxial lateral aberrations have been verified and tested, in which the aberration coefficients are solved by asymptotic solutions of paraxial equation. Result completely proves that the approach based on asymptotic solutions to solve the paraxial lateral aberrations are practicable and accurate enough. The paraxial chromatic aberration of magnification of third order and the paraxial chromatic aberration of third order have been firstly derived, and the Recknagel-Artimovich formula of paraxial chromatic aberration of second order which possess an greatest part in the whole paraxial lateral aberrations has been deduced and confirmed. A simple and clear form for expressing paraxial lateral aberrations of imaging electron optics is suggested for practical use. Results of the present paper will have theoretical value for aberration theory of imaging electron optics and practical significance for the design of image tubes.     

2 × Zoom Ratio Telecentric Projector Lens Design for 1080 P High Definition Television with Minimum 8000 K Color Temperature

In today's digital age, digital projectors and their application are gaining in significance, especially in the home theater area where the projected area is more than hundred inches. More attention has to be paid to the design of these than of ordinary data projectors due to the enhancement of both definition and contrast for home theater projectors. This complicates the optical design of the projector, especially in 1080 P flat plane panel resolution requirements with strong offset of 130%, whose semi-image height (18.6 mm) is very close to that of 35 mm film (20 to 21 mm). In this paper the lens design samples focus on the application of a projector with a 1080 P digital micromirror device (DMD) system with 10.68 μm per pitch. Such lenses have the telecentric design on the image side because of the total internal reflection (TIR) prism. The complicated design is the reason for this: firstly, there must be a very long back focal length due to the huge TIR prism and zoom mechanical system; secondly, there is an extremely relative luminance requirement (70% minimum) at semi-image height (18.6 mm); thirdly, there are difficulties in the elimination of lateral aberration due to the limited choice of glass and, fourthly, there is a 2 × zoom ratio with modulation transfer function requirement of 40% at 501p/mm at a semi-image height of 18.6 mm minimum and, most important, limited total overall length. The lens design with 2 × zoom ratio for 1080 P resolution was presented with great success; the optimal calculation of lateral chromatic aberration via genetic algorithm (GA) was introduced in this research and then a local minimum of lateral color aberration was identified.     

光学系统纵向色差的仿真及验证

现有的焦距检测方法通常由于检测仪器光源波长与光学系统不完全匹配从而产生纵向色差影响检测结果。针对这一问题，研究光学系统纵向色差的变化规律，并确定在400 nm～1 000 nm波段用于表示其函数关系的Conrady公式和复消色差特性公式。根据光学系统近焦位置的离焦量与位置呈线性关系的特性, 提出使用菲索干涉仪测量5种不同波长的焦距位置，获得单透镜和双胶合镜头的纵向色差曲线。实验结果表明: 在400 nm～1 000 nm波段单色系统和消色差系统的纵向色差的函数关系分别符合Conrady公式和复消色差特性公式，研究结果为焦距的理论计算和精确检测提供了新的思路和参考。