Design Of Zoom Optical System For Deep-sea Exploration With Large Field Of View And High Resolution

At present,the exploration of the deep sea has become a hot research topic among countries.In order to meet the needs of China’s deep-sea exploration,this thesis designs a deep-sea dedicated continuous zoom optical system that can image underwater at11000 m.This thesis first analyzes the optical characteristics of water and its influence on underwater imaging,and after the study of zoom theory,on the basis of design requirements,plus the factors that need to be considered in the optical design of deep sea,finally determine the mechanical negative group compensation zoom mode.On the basis of the patent,the optical system is gradually improved and optimized.In the process of optimization,the incidence Angle of the main light on the image plane is controlled,so as to form the telecentric light path of the image side and achieve the uniform illumination effect of the image plane.Change different material collocation,achieve achromatic,reduce the purpose of secondary spectrum.At the same time,the aspheric surface is added to balance the off-axis aberration.In particular,this thesis focuses on the underwater optical window,from the aspect of surface shape and material analysis,after comparison,the sapphire spherical optical window is selected.The hydrostatic pressure in the deep sea is very high,and the problem of the surface shape change caused by the hydrostatic pressure squeezing of the underwater light window is not considered in the optical system used in the deep sea.This thesis studies the deformation of the optical window,on the depth of underwater 11000 m optical window after analyzed the statics,the mirror surface displacement nephogram and form changing file,will face changes was imported into the window light machine data conversion software,after will face changes in Zernike polynomial form fitting,and plug in to the optical software optimizes.Finally,a deep-sea zoom optical system with large field of view,high resolution and high magnification ratio is designed.The zoom system can realize the function of 5.7° ～ 90° full field of view and 10 times continuous zoom.At 208 lp /mm,the MTF value of the whole zoom area is greater than 0.3.The maximum distortion of each zoom position is less than 3%.The working distance of the system is 5m,the f-number of the whole zoom is constant at 3.0,and three aspheric surfaces are used.The total length of the system is 260 mm.The tolerance of zoom system is analyzed and the zoom CAM curve is drawn.The results show that the deepsea zoom optical system designed in this thesis has good imaging quality,compact structure,smooth zoom curve,and good tolerance performance.It can meet the needs of practical application,and can be used as the lens of the deep-sea 4K zoom camera.