Research On All-Reflective Zoom Optical System

Research on all-reflective zoom optical system has important value in the area ofearth observation. One important application of researching on earth observationtechnology is in the military field, whose intentions are military reconnaissance andlarge scale mapping. General requirements of military reconnaissance is longdetection distance, which demands the target can be not only surveyed with smallmagnification in large areas, but also observed with large magnification in small areas.Therefore, the zoom systems which have long focal length, wide field-of-view arerequired. However, the engineering design and implementation of optical systemswhich have long focal length, and wide field-of-view are more difficult, even morethe zoom system. So the design problems about the zoom system which are based onlong focal length, low F-number, wide field of view (FOV) becomes difficult problemin zoom system design field. Moreover, it becomes competing research subjectsthrough many scientific research institutions at home and abroad.Reflective zoom system is relatively easy to carry out long focal length and largeaperture design. It has the feature of switching the field of view and zoomingcontinuously during zoom process. During earth observation or militaryreconnaissance process, using one reflective zoom system can complete both targetsearch and target collimation. This paper is just based on the requirements of thedevelopment about the new generation and high performance, miniaturization andlightweight load designed to design a new kind of unobscured reflective zoom opticalsystem which has large zoom ratio, wide field-of-view and excellent image quality.The paper is mainly based on the integrative design of all-reflective zoom opticalsystem. Firstly, the paper educes its purpose and significance, and introduces theconfigurable form of internal and overseas some zoom optical systems and their implemental manners. Secondly, the paper researches the basic theory about zoomsystem and correlative theory of the reflective zoom optic design, and introduction themethod to achieve the initial construction parameters, which based on the3rd-orderaberration theory. At the same time, the disadvantages of co-axial reflective zoomsystem are analyzed. Moreover, the method of design off-axial reflective zoom systemto make up for the disadvantages of co-axial reflective zoom system is introduced.Thirdly, based on the detailed indexes, an optical system was designed with theoptical design software-CODEV. At the same time, the image quality is evaluated andthe tolerance analysis is carried out. The result shows that the image of the zoomoptical system satisfied the design demand. Finally, the research work in the paper issummarized and the expectation about the after continue research work is carriedthrough.