含非球面头罩的光学系统像差校正技术研究

	含非球面头罩的光学系统像差校正技术研究
	王超
学位类型	博士
导师	张新
	2014-07
学位授予单位	中国科学院大学
学位专业	光学
摘要	近年来，随着雷达探测、精确反导等军事对抗能力的迅猛提升，对飞行器的空气动力学性能的要求日益提高。为实现最优的气动外形结构，设计飞行器光学头罩（整流罩）时往往采用流线型非球面形状替代传统的半球形。含非球面头罩的光学系统（以下简称非球面头罩光学系统）通常利用俯仰-偏航支架来进行扫描成像，在扫描视角不为零时，非球面头罩将体现出严重的非旋转对称特性，给光学系统引入大量像差，且像差的大小随视轴角的改变而发生剧烈变化。由于非球面头罩光学系统的大偏心、大倾斜特性，经典光学像差和波像差理论难以应用于该光学系统的像质分析；传统光学结构形式也难以校正该系统的动态像差，给光学设计提出了巨大难题。本文致力于非球面头罩光学系统的像差特性分析与像差校正理论研究。主要创新性成果为：根据系统实际应用需求，提出了两种新颖的非球面头罩光学系统的像差校正理论与方法；并探索了两种空气动力学性能良好，同时引入像差较小的新型非球面头罩外形。主要研究工作和结果如下：1. 首先对非球面光学头罩的几何特性和三阶像差特性进行分析：建立了非球面光学头罩几何参数与光学设计软件输入参数之间的转化关系式；将泽尼克多项式像差理论和矢量形式的波像差理论相结合，构建非球面头罩光学系统像差评价模型，并根据矢量像差场中心偏移的特性，指出可利用偏心元件来平衡头罩倾斜引起的彗差。在以上理论基础上深入探讨了非球面头罩光学系统的几何外形特征与像差特性间的关联，指出非球面头罩子午和弧矢曲率半径差值较大，以及光束透过非球面头罩后产生的视轴偏差和非对称光瞳特性是引入严重像差的根本原因。2. 根据非球面头罩光学系统结构和像差特性，选取几种适用于进行非球面头罩像差校正的复杂面形函数，包括透射式Wassermann-Wolf曲面、平面对称表面和高斯径向基函数表面等，分析它们因自身数理模型而表现出的有利于非球面头罩像差校正的光学特性，为以上面形在后文应用于像差校正元件设计建立了理论依据。3. 为解决非球面头罩光学系统难以建立合理的初始结构的问题，提出一种反射式Wassermann-Wolf方程设计理论。以反射定律和光路计算方法为基础，首次推导了一对适用于指导高度非旋转对称的折反射式系统设计的Wassermann-Wolf方程，利用该方程并结合最小二乘拟合的方法，解算出的两镜像差校正器初始结构能够兼顾各个子扫描视场的像差校正需求。利用平面对称的矢量像差理论，分析了该平面对称反射式系统的像差特性，提出了利用反射镜倾斜来进行残余动态像差补偿的设计方案。最后基于以上理论完成了完整非球面头罩光学系统设计实例，该系统在各子扫描视场成像质量接近衍射极限。4. 为解决以往非球面头罩光学系统搜索视场偏小的问题，提出一种基于拱形像差校正元件和动态校正器的非球面头罩像差补偿方法。拱形校正板利用平面对称面形设计，以满足子午和弧矢方向不同的像差补偿需求。采用高斯径向基函数表征动态校正器表面面形并证明了其可行性，实现了变形反射镜的表面光学特性的精确仿真。通过设计实例验证以上像差补偿方法的有效性，设计结果表明该方法同时实现了超大扫描视场与良好成像质量。5. 为从根本上解决现有非球面头罩光学系统像差校正手段过于复杂的问题，构造了两种新型非球面，即球-圆锥面和球-圆锥-多项式面。给出了这两种表面的数学定义并证明表面是光滑连续的，之后推导了具有这两种外形的头罩的几何参数设计公式，并通过仿真，证实这两种头罩不但具备良好气动性能，同时在±75°特大扫描视场内仅引入极小像差，从而大大简化了校正系统结构，降低系统重量和成本并增加其可靠性。
其他摘要	As the technique as radar detection and precision anti-missile development rapidly, the requirement of aerodynamic performance for the aircraft becomes higher and higher. In order to realize the optimial aerodymanic outer shape, the traditional hemispheric shape is frequently replaced by the streamline aspheric shape in the design of the optical dome on aircraft. The optical system with an aspheric dome (hereinafter referred to as aspheric dome optical system) usually uses the pitch-yaw gimbal to scan and image, when the scaning angle is not zero, the aspheric dome will show serious asymmetrical performance, and induce a mass of aberration for the optical system, and the amount of the aberration acutely changes as the scaning angle. Due to the serious decenter and tilt performance of the aspheric dome optical system, the classical optical aberration theory and wavefront aberration theory cannot be used in the analysis of this system, and traditional optical structures are failed to correct the dynamic aberrations of this system, which brings a great challenge for the optical design.This thesis concentrated on the analysis of aberration characteristics and the research of aberration correcting theory for the aspheric dome optical system. The main innovate productions are: based on the practical application requirements, two novel aberration correcting theory and method are proposed. And two novel aspheric dome shapes which have good aerodyamnic performance and induce less aberration are bringed forward. The dominating work and results in this paper are as follows:1. At first, the geometrical performance and third-order aberration characteristics for the aspheric optical dome are analyzed: The transformation between geometrical parameters of an aspheric dome and the input of optical design software is established. Zernike polynomials aberration theory and vector wavefront aberration theory are combined to establish the aberration evaluation model for the aspheric dome optical system. Based on the displacement property of the vector aberration field center, the design idea of using a decentered corrector to balance the coma induced by the tilt of the dome is proposed. On the base of above work, the contact of geometrical characteristics and aberration performance for the aspheric dome optical system is deeply discussed, and the fundamental causes of the production of large aberration are pointed out: Firstly, there is a dramatic difference between tangential and sagittal radius of curvatures of the aspheric dome; secondly, when the ray fan pass through the aspheric dome, the line of sight deviation and asymmetrical pupil distribution present themselves.2. Based on the structure and aberration characteristics of the aspheric optical dome, a few complex surfaces, including the dioptric Wassermann-Wolf surfaces, the plane symmetric surface and the Gaussian radial basis function surface, are selected. These surface types are fit for being used in aberration correcting for the aspheric dome. The optical characteristics of them which are beneficial to aberration correcting for the aspheric dome are discussed. These optical characteristics are root in the mathsmatic models of these surfaces. The discussion provides a theoretic foundation for the application of these surface types in the design of aberration correctors below.3. To solve the problem that a reasonable intial structure of the aspheric dome optical system is difficult to established, a design theory based on reflective Wassermann-Wolf (W-W) equations is proposed. On the basis of reflection law and light path caculation method, a pair of Wassermann-Wolf (W-W) equations relating to designs of highly non-rotationally symmetric reflective systems are derived for the first time. Combined this way with the least square fitting method, we can get an intial structure of a two-mirror aberration corrector concerned the aberration-corrected need of every field-of-regard(FOR) point. Based on the plane-symmetric vector aberration theory, the aberration properties of this plane-symmetric reflective system is analyzed, and the design scheme of tilting mirrors to compensate the residual dynamical aberration in different FOR. Finally, the integrated aspheric dome optical system design example is finished, and the imaging quality of this system approaches to the diffraction limit. 4. To overcome the problem that the searching FORs of existing aspheric dome optical systems are relatively narrow, an aberration compensating method for the aspheric dome optical system based on the combination of an arch corrector and a dynamic corrector is proposed. The arch corrector is designed in plane-symmetric surfaces to satify different aberration-corrected needs in tangential and sagittal directions. The surface shape of the dynamic corrector is represented by Gaussian radial basis function, and the feasibility of this represented method is proved. The accurate simulation of the optical properities of the deformable mirror is achieved. Through a design example the validity of this aberration compensating method is proved, and the design result indicates that this method reaches the requirements of super wide FOR and high imaging quality at the same time.5. To radically solve the problem that the existing correcting methods are excessively complex, two novel asphere mathematic models are established, which are sphere-cone (SC) and sphere-cone-polynomial (SCP) surfaces. The smoothness and continuity of these two surfaces are proved. The equations used to decide geometrical parameters of domes with these shapes are deduced. Through the simulations, it is proved that these two domes have not only good aerodynamic performance, but also introduce the minimal amount of aberration in ±75° super scanning field. So the correcting system structure is significantly simplified, which reduces the weight and cost and enhances the reliability of the system.
语种	中文
文献类型	学位论文
条目标识符	http://ir.ciomp.ac.cn/handle/181722/41475
专题	中科院长春光机所知识产出
推荐引用方式 GB/T 7714	王超. 含非球面头罩的光学系统像差校正技术研究[D]. 中国科学院大学,2014.

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