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Design Of Large Zoom Ratio System

Posted on:2013-01-10Degree:DoctorType:Dissertation
Country:ChinaCandidate:W CaiFull Text:PDF
GTID:1112330371998881Subject:Optics
Abstract/Summary:PDF Full Text Request
With the development of optical theory and processing technology, the role ofzoom lens in areas of daily life, science and education, reconnaissance and nationaldefense is more and more important. Getting the target in wider range and tracking thefurther target can make you obtain more information. While that all based on largezoom ratio system.Once zoom ratio approach100X, some fundamental aberration correctionlimitations appear, mainly due to the differential magnification of residual aberrationcorrection through the zoom ratio close to100X. In addition, wide angle fields ofview produce other entrance pupil control limitations which if not corrected leads toexcessively large diameter lens elements, usually in the front objective region.Because of its special configuration, Compound Zoom Lens can break theconventional zoom barrier. The special structure having two zoom groupings orportions separated by an intermediate image. The intermediate image varies throughzoom, so the first zoom grouping should not correct aberration under large image andlarge image NA condition, the second zoom grouping should not correct aberrationunder large object and large object NA condition. This arrangement is key to theoverall high performance of compound zoom lenses. Because it facilitates aberration correction in different areas of the lens at low zoom groupingmagnifications while controlling the entrance pupil position. So, we use compoundstructure to realize large zoom ratio. The main research contents are sμmmarized inthe following aspects:1. The conventional zoom theory are analyzed and sμmmed up in detail, thepaper discussed the characters of various types, and contrasted the advantages ofdifferent zoom structures.2. Clever established function on condition that the element optical power isunchanged during zoom. Using the functions to solve the distribution of optical power,then solving the movement curve of the system group.3. Designed a visible100X continuous zoom system by using the conventionalzoom theory. The system can realize good image quality without utilizing specialmaterial, aspherical and diffractive elements.4. Designed a visual191X continuous zoom system by using the compoundzoom theory. And the design process is given in detail. The LWIR continuous100Xsystem has better image quality, and the value of MTF closed to diffraction limit.5. The compound zoom system has more complex structure, and its transmissionratio is lower. In order to solving the problem, we proposed a new double tube largezoom structure. The structure will realize large zoom ratio, high transmission ratio,light and small with the development of optical design theory.
Keywords/Search Tags:lens design, zoom system, focus power distribution, large zoom ratio
PDF Full Text Request
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