共查询到17条相似文献,搜索用时 343 毫秒
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提出了计算动态电子光学成像系统时间像差系数的新方法——直接积分法.以阴极面逸出的轴向电子初能为εz1(0≤εz1≤ε0max)的近轴电子 轨迹为比较 基准,给出了时间像差的定义,详细叙述了直接积分法并给出求解动态电子光学成像系统时 间像差系数的积分表达式.τ变分法求得的二级几何时间像差系数必须求解微分方程, 而直接积分法求得的二级几何时间像差系数全部以积分形式表示,仅需进行积分运算,更适 用于成像系统的实际计算与设计.
关键词:
电子光学成像系统
阴极透镜
动态电子光学
时间像差理论 相似文献
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《中国光学与应用光学文摘》2006,(5)
O436.12006054760关于动态电子光学时间像差理论的研究=On the theoryof temporal aberrations for dynamic electron optics[刊,中]/周立伟(北京理工大学信息科学技术学院光电工程系.北京(100081))//北京理工大学学报.—2006,26(5).—377-382提出了直接积分法(DI M)研究动态电子光学成像系统时间像差的理论。以阴极面逸出的某一轴向电子初能为εz1(0≤εz1≤ε0max)的近轴电子轨迹为比较基准,给出时间像差的新定义,导出了动态电子光学成像系统时间像差系数的积分表达式。利用静电聚焦同心球系统理想模型的解析解检验了直接积分法(DI M)… 相似文献
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将从近轴解出发研究两电极静电同心球系统的空-时轨迹及其像差.由近轴轨迹方程和近轴运动方程出发,先求解两电极静电同心球系统中自光阴极逸出的运动电子的近轴空间-时间轨迹,然后讨论此系统的静动态电子光学及其空间-时间像差,揭示近轴光学系统成像的一般规律.文中定义和推导了各级近轴空间像差和近轴时间像差,得到了与关于近轴空间-时间像差同样的结论,表明完全可以直接由近轴轨迹方程和近轴运动方程出发来研究理想成像及其空间-时间像差. 相似文献
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《中国光学与应用光学文摘》2006,(4)
TH703 2006042841关于Tau变分法研究电子光学成像系统的时间像差理论=On the temporal aberration theory of electron optical i m-aging systems by Tau-variation method[刊,中]/周立伟(北京理工大学信息科学技术学院.北京(100081)) , M AMonastyrski…∥电子学报.—2006 ,34(2) .—193-197采用新的时间像差定义,考察了“Tau变分法”研究电子光学成像系统的时间像差理论。研究表明,“Tau变分法”所给出的以微分方程形式表示的几何时间像差系数亦可获得积分形式的表示式,证明了“直接积分法”与“Tau变分法”这两条途径殊途同归。参6… 相似文献
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通过复合电磁同心球系统的理想模型,对成像电子光学近轴方程的轨迹求解进行探讨。首次推导了该系统的近轴电子轨迹的转角及近轴方程的两个特解的解析表达式,探讨了近轴成像性质,并将结果推广到两电极静电同心球系统、均匀平行复合电磁系统和静电近贴系统中。 相似文献
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在成像电子光学中,静电聚焦同心球系统具有一系列宝贵的性质,其电位分布与电子轨迹能以解析形式表示,可以定量地研究系统的电子光学成像特性与横向像差。尽管前人已有不少研究,但都限于零级近似成像的认识,且其中存在着不少谬误。本系列文章将全面研究静电聚焦两电极与多电极同心球系统中电子的运动轨迹、电子光学成像特性与横向像差,探讨电子束在成像段形成的图像弥散,得出一些新的结论和认识,纠正文献中存在的一些谬误,建立自己的理论体系。本系列文章的第一篇主要探讨电子在两电极同心球系统中在静电场作用下的运动轨迹,导出了两电极静电聚焦同心球系统中自阴极面逸出的电子轨迹在极坐标系下的表示式ρ=f(φ)与圆柱坐标系下新的轨迹方程的表示式r=r(z),给出了自光阴极逸出的电子在成像段的行进轨迹的交轴位置及其斜率的近似和精确表示式。本文为全面研究静电聚焦同心球系统的电子光学性质及其像差奠定基础。 相似文献
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基于平面对称光学系统的波像差理论,给出了鱼眼镜头各类像差的波像差计算表达式,利用自相关积分法计算了它的调制传递函数,采用8节点的高斯-勒让德数值积分方法求解了其自相关积分;分析了鱼眼镜头倍率色差对确定空间频率光栅的相位改变量,给出了C(656.3nm)、D(589.3nm)、F(486.1nm)离散光谱的倍率色差的调制传递函数计算表达式.利用本文方法和Zemax快速傅里叶变换法分别计算两个鱼眼镜头系统的调制传递函数,并进行了对比.结果表明,对于中小孔径的鱼眼镜头成像系统,本文方法和仿真得到的结果较好地吻合. 相似文献
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A new approach to the theory of temporal aberration for cathode lenses is given in the present paper. A definition of temporal aberration is given in which a certain initial energy of electron emission along the axial direction εz1 (0εz1ε0max) is considered. A new method to calculate the temporal aberration coefficients of cathode lenses named “direct integral method” is also presented. The “direct integral method” gives new expressions of the temporal aberration coefficients which are expressed in integral forms. The difference between “direct integral method” and “τ-variation method” is that the “τ-variation method” needs to solve the differential equations for the three of temporal geometrical aberration coefficients of second order, while the “direct integral method” only needs to carry out the integral calculation for all of these temporal aberration coefficients of second order.All of the formulae of the temporal aberration coefficients deduced from “direct integral method” and “τ-variation method” have been verified by an electrostatic concentric spherical system model, and contrasted with the analytical solutions. Results show that these two methods have got identical solutions and the solutions of temporal aberration coefficients of the first and second order are the same as with the analytical solutions. Although some forms of the results seem different, but they can be transformed into the same form. Thus, it can be concluded these two methods given by us are equivalent and correct, but the “direct integral method” is related to solve integral equations, which is more convenient for computation and could be suggested for use in practical design. 相似文献
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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. 相似文献
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In imaging electron optics, for a concentric spherical system composed of two spherical electrodes with electrostatic focusing, the electrostatic potential distribution and the spatial-temporal trajectory of electron motion can be expressed by analytical forms. It is naturally to take such system as an ideal model to investigate the imaging properties, as well as the spatial-temporal aberrations, to analyze its particularity and to find the clue of universalities and regularities. Research on this problem has important significance, which can afford theoretical foundation not only in studying static electron optics for the night vision devices, but also in studying dynamic electron optics for high-speed image converter tubes.In the present paper, based on the practical electron ray equation and electron motion equation for a bi-electrode concentric spherical system with electrostatic focusing, the spatial-temporal trajectories of moving electrons emitted from the photocathode have been solved, the exact and approximate formulae for image position and flight time of electrons, have been deduced. Start from solutions of spatial-temporal trajectories, the electron optical spatial-temporal properties of this system are then discussed. According to the definitions of spatial-temporal aberrations, the paraxial and geometrical lateral aberrations, as well as the paraxial and geometrical temporal aberrations, have been deduced, that are classified by the order of and . 相似文献
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Keisuke Araki 《Optical Review》2005,12(3):219-222
Off-axial optical systems are an extended concept of co-axial optical systems, where deflection surfaces are arranged along the folded reference axis. A newly proposed aberration expression with two kinds of 4-element vectors is simple and comprehensive in its order relation for off-axial optical systems. Using these vectors and tensor algebra, it is shown that aberration expansion coefficients for an arbitrary azimuth can be calculated by transforming the coefficients of 4-element fundamental ray vectors, and the aberration contributions of each surface are in general represented not in simple sum form, but in converted sum form. The aberration contribution of cross terms that exist over the third order, can also be clearly represented using tensor coefficient representation. This paraxial and aberration analysis of off-axial optical systems is very useful in the actual design of optical systems. 相似文献
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According to the structural characteristics of aspheric off-axis two-mirror optical system, the imaging characteristics of the system were analyzed by using primary aberration theory. Based on the characteristics of different aspheric surfaces, the vector expression of system aberrations was derived. Using the Seidel coefficients, the primary wave aberration of systems were expanded and values of system aberration for different aspheric surface shapes were specifically calculated. After the evaluation index of the off-axis structure was determined, the imaging qualities of different surface shape combinations were compared. Then the optimal surface shape selection method was analyzed by quantitative comparison results. The results show that compared with other reflector combination methods, the spherical aberration, coma and astigmatism of the off-axis double paraboloid system are all 0, the wavefront RMS is much better than λ/14 (λ=0.587 6 μm), and the Strehl ratio is greater than 0.8. According to the calculation results, it not only has a stronger ability to suppress multiple primary aberrations, but also can effectively compress the volume of the system. Copyright ©2022 Journal of Applied Optics. All rights reserved. 相似文献