Design And Research Of Optical Imaging System With Liquid Crystal Lens

Compared with traditional fixed-focus glass lenses,liquid crystal lenses have the advantages of variable focus,small size,thin thickness,light weight and long life.Liquid crystal lenses are capable of varying the focal length under electric field drive regulation over a reaction time of the order of milliseconds.Due to its characteristics without mechanical moving parts,it has a wide range of applications in monitoring field,beam control and shaping,illumination,adaptive optics,and medical imaging.However,the aperture of liquid crystal lens is small,which greatly limits the amount of light entering the system,and is one of the important factors hindering the wide application of the liquid crystal lens.This paper designs two optical imaging systems.One is designing a system with liquid crystal lens to enlarge entrance pupil diameter to increase incident light.The other is using a foveated system to keep a part clear within the field of view,including the following contents.The current situation of liquid crystal lens at home and abroad is analyzed,and an idea of using optical design to increase the aperture of liquid crystal lens is proposed with magnification keeping constant.According to the proposed target,the design of the liquid crystal lens optical system that realizes a larger entrance pupil diameter is completed by using ZEMAX.The image quality evaluation and tolerance analysis of the optical system are carried out.Starting from the initial structure selection and then designing a high-resolution lens,the liquid crystal lens has a hole diameter of 2 mm and is used as the aperture stop of the system.The system has a entrance diameter of 2.8 mm and a magnification of 1.4 times,double the amount of incident light.The field of view,wavelength ranges,focal length and total length are ±25o,480~643 ?m,7.5 mm,18 mm,respectively.The full field of view MTF ? 0.30(227 lp/mm),and the relative illumination is > 90%.During the process of changing the focus of liquid crystal lens,the magnification of objects keeps constant.The design scheme is modeled and the actual mechanical structure is designed and processed.The imaging quality,brightness distribution,focus test and magnification change analysis of the liquid crystal lens optical system are tested in the laboratory.The actual value of MTF 50 reaches 0.25,increasing by 60% compared with the foveated imaging experiment and the incident light is doubled from simple fitting in the front.The magnification of objects is within one pixel in the experiment.Inspired by the characteristics of variable resolution when the human eye observes things,a set of foveated imaging system is designed by using liquid crystal lens.The principle of the system is analyzed,and the influence of the size and aperture of the liquid crystal lens on the imaging quality is measured.The imaging quality of the system is measured and used the system for imaging.