基于衍射成像系统的薄膜元件关键技术研究

发布时间：2018-03-15 19:49

本文选题：大口径　切入点：衍射成像系统　出处：《中国科学院长春光学精密机械与物理研究所》2017年博士论文　论文类型：学位论文

【摘要】：高分辨率空间对地光学遥感相机是目前世界上空间光学的热点研究领域。地球静止轨道对地观测相机是航天遥感领域中获取空间信息的重要工具之一,具有极高时间分辨率和超大观测幅宽的特点。静止轨道光学遥感能够实现星下点对地球表面三分之一区域的连续观测,但是实现大范围观测的同时,地面像元分辨率会降低。增长焦距、增大口径是提高空间相机分辨率的最有效方法。若希望在地球静止轨道实现1 m像元分辨能力,相机的口径要达到20 m。随着口径的增大,传统形式的反射式空间望远系统不管是制造技术,还是发射能力以及空间展开、调整技术等方面,实现起来已经越来越困难。考虑到必需的支撑和控制结构,光学系统的重量与口径的平方成正比例关系。随着口径的增大,控制越来越复杂,传统光学系统在硬件、软件、系统集成和测试等各方面的成本急剧增大。与反射式光学系统相比,以薄膜材料作为系统物镜的衍射成像系统具有可实现大口径、结构轻量化、可折叠展开、公差宽松、易复制等特点,能够显著节省制造与发射成本,在静止轨道高分辨率成像领域中具有广阔的应用前景。本文针对基于薄膜材料的衍射成像系统,从设计到元件加工进行了深入的研究,其主要内容分为以下几个方面:1、使用Zemax光学设计软件,设计并优化衍射式望远镜系统,基于Schupmann消色差原理,设计校正镜组平衡衍射物镜的色差,展宽系统使用波段。完成5 m口径的衍射望远镜系统设计,系统成像性能接近衍射极限。同时,设计一个300 mm口径的衍射望远镜样机,用以验证基于衍射成像技术的系统成像性能。对衍射成像系统中的加工公差,位置公差及拼接公差进行分析,以验证衍射元件应用在大口径望远镜系统上的可行性。2、搭建了基于聚酰亚胺薄膜材料,可用于大口径薄膜衍射元件制造的加工平台。建立并优化了轻质、高衍射效率位相型薄膜衍射元件加工工艺流程。探究了基于激光直写与Ar离子束物理刻蚀的组合工艺,实现熔石英玻璃基底的复制模板的制作。选取透明有机材料聚酰亚胺作为薄膜基底材料,采用模板复制方法,将设计结构通过模板转移至聚酰亚胺薄膜表面。根据所探究的工艺流程,分别完成了两块不同基底材料的300 mm有效口径的衍射物镜的制作。3、完善了多台阶薄膜衍射元件加工全过程中的制作误差分析,将制作误差分为复制基板加工过程中引入的制作误差与薄膜转移过程引入的制作误差。复制基板误差主要包括刻蚀深度误差、套刻误差、线宽误差。薄膜转移过程中引入的制作误差主要分为线宽转移误差与深度转移误差。对制作误差进行解析分析,利用Matlab软件进行仿真,分析制作误差与薄膜衍射元件衍射效率之间的关系。4、对实验制作的两块不同材质的衍射元件进行测试,以评估其性能。设计并搭建检测光路,测试衍射元件的衍射效率,并结合实验测得的各类制作误差,验证了制作误差与衍射效率关系的分析模型有效性。搭建衍射望远镜系统成像光路,分别通过星点像与分辨率板,测试系统的成像性能。论文的研究工作表明基于薄膜材料的衍射式成像系统为未来实现大口径静止轨道高分辨成像提供了一个新思路。通过模板复制方法制作的薄膜具有轻量化、性能稳定、光学性能优异、衍射效率高的特点。本文的工作为未来空间超大口径薄膜衍射成像系统的研究提供了理论与技术基础。
[Abstract]:High spatial resolution is currently a hot research field in the world of space optical remote sensing camera. The geostationary orbit is one of the important tools to obtain spatial information in the field of aerospace remote sensing of earth observation camera with high time resolution and ultra width characteristics. Observation of geostationary orbit optical remote sensing can achieve continuous observation of 1/3 of the earth's surface area the ground, but to achieve a wide range of observations at the same time, the ground pixel resolution will reduce growth. The focal length, increasing the diameter is the most effective way to improve the resolution of the space camera. If you want the ability to distinguish in geostationary orbit to achieve 1 m pixel camera, the aperture to reach 20 m. with the diameter increasing, reflecting the traditional form of space telescope system whether manufacturing technology, or ability to launch and space expansion, adjustment of technology, it has been more and more Difficult. Considering the support and control structure is required, the weight and the diameter of the optical system is proportional to the square. With the diameter increasing, the control is more and more complicated, the traditional optical system in hardware and software, and the system integration and testing cost increases rapidly. Compared with the reflective optical system with thin film material as the diffraction imaging system can realize the objective system with large diameter, lightweight structure, folding, tolerance, easy to copy, can significantly reduce manufacturing costs and emission, and has broad application prospects in the geostationary orbit high resolution imaging field. According to the diffraction imaging system based on thin film materials, from the design the processing element is studied, the main contents are as follows: 1, using the Zemax optical design software, design and optimization of diffractive telescope system based on Schupma NN the achromatic principle, design color correction lens balance lens system using diffraction, broadening band. To complete the design of 5 m aperture diffractive telescope system, imaging system performance is close to the diffraction limit. At the same time, the design of a 300 mm aperture diffractive telescope prototype to verify based on diffraction imaging system for imaging performance. Tolerance diffraction imaging system, position tolerance and tolerance are analyzed to verify the connection, diffractive element is used in large aperture telescope system on the feasibility of.2, build a polyimide film material can be used for processing platform based on large aperture optical diffraction element manufacturing. To establish and optimize the lightweight, high diffraction efficiency of phase type thin film diffraction element process. To explore the combination of laser direct writing technique and Ar ion beam etching based on physical realization, copy the template of fused quartz glass substrate production. Select Transparent organic polyimide material as the film base material, using the template replication method, the design of structure by template transfer to the polyimide film surface. According to the process of inquiry, were completed in.3 making two pieces of different base materials the effective aperture of 300 mm diffraction lens, improve the whole process of fabrication error of multi step thin film diffraction element processing in the analysis, the error is divided into making errors in the process of copying substrate and film transfer process is introduced. The fabrication errors of replication error mainly includes substrate etching depth error, alignment error, line width error. Making errors in the process of the transfer film is divided into linewidth error and depth error. Transfer transfer analysis analysis of fabrication errors, simulated using Matlab software and analysis of relationship between.4 production error and the diffraction efficiency of thin film diffraction element To test, two different materials produced by diffraction element experiment, to evaluate its performance. Designed and built the detection optical path, the diffraction efficiency of diffractive element test, combined with the experimental measured all kinds of fabrication errors, verified the model validity analysis of relationship between the manufacturing error and the diffraction efficiency of optical diffraction imaging structures. The telescope system, respectively and resolution through the star like plate, the imaging performance of the test system. The research work of this paper shows that the diffractive imaging system based on thin film materials for the future implementation of large caliber geostationary orbit high resolution imaging provides a new idea. Through the method of making film template replication has light weight, stable performance, excellent optical performance the characteristics, high diffraction efficiency. To provide theoretical and technical basis for the future research work space of large diameter thin film diffraction imaging system.

【学位授予单位】：中国科学院长春光学精密机械与物理研究所
【学位级别】：博士
【学位授予年份】：2017
【分类号】：V443.5

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