Study Of Visible/infrared Common Aperture Zoom Optical System

With the development of all kinds of detection,camouflage technologies and the complication of operating environment,the traditional optical systems can't meet the requirement for application bit by bit.The dual/multi-band zoom systems with a large aperture,long focal length have become an important direction in the future,which have unparalleled advantages.On the one hand,they can not only image in multiband,obtain the comprehensive and accurate information of the important objects;but also possess the ability of all-weather reconnaissance and counter-camouflage.On the other hand,they also possess the ability to zoom for searching target in a large area and tracking target in a small area;they have a broad application and are worth researching.As a result,in this paper,the dual-band zoom systems with a large aperture,long focal length are studied,and a zoom optical system that achieves visible/medium-infrared dual-band imaging with common aperture is designed.Based on the recent progress of studies,in this paper,three structures of optical system and three realization methods which can be applied in dual-band imaging system are studied.As a result,the catadioptric systems that have common aperture are selected.In this system,the visible and the medium-infrared optical system shares the reflection part,which is an off-axis reflective non-power system.Then,the light beam from the reflection part is split by beam splitter with special coating,and different wavebands of light enter different detectors.For the visible optical system,the focal length is 200mm~2000mm,the working waveband is 486~656nm,relative aperture is 1:5,the detector and pixel sizes are 1280×1024 and 4.7?m,respectively.For the mid-infrared optical system,the focal length is 200mm~2000mm,the working waveband is 3.7-4.8?m,relative aperture is 1:5,the detector and pixel sizes are 320×320 and 25?m,respectively.The result shows that the imaging quality of the visible optical system and the mid-infrared optical system is satisfying,and the zoom motion curve is smooth without fold point.Finally,some important issues including operating temperature and tolerance,are analyzed.The result shows that the imaging quality of the visible and mid-infrared optical system can be acceptable from-40oC to 60oC and from 0-1 standard atmosphere pressure,and the tolerance is reasonable.