Design And Application Of Spherical Aberration Free Continuous Zoom Micro Liquid-filled Cylindrical Lenses

Zoom lenses have greater flexibility and adaptability compared to fixed-focus lenses,are widely used in modern micro-optical systems,optical communication systems,aerospace and military operations and other areas.With the rapid development of optical technology,the traditional mechanical zoom lens by changing the relative position of the lens group to achieve the zoom capability,has gradually unable to meet increasing needs of the development of the lens miniaturization and integration modern optical system.With the advantages of compact structure,easy integration,no mechanical wear and tear,and flexible control,the liquid lens has become a hot research topic in recent years.However,compared with common axially symmetric spherical lens,cylindrical lens has less research which is irreplaceable in beam shaping.A liquid-filled micro continuous zoom cylindrical lens system based on a PDMS substrate is designed and machined in this paper,which achieves large magnification ratio and high image quality,and is used to measure liquid refractive index.The research includes the following:1.A design scheme is proposed to bury symmetrical hollow-core cylindrical lenses and biconvex cylindrical lenses into PDMS substrates sequentially to form a continuous zoom cylindrical lens system:The continuous zoom capability of the cylindrical lens system can be realized by injecting liquid with different refractive index into the hollow core area of the zoom system;Rational design of cylindrical lens radius of curvature,thickness and material to eliminate system aberrations throughout the zoom range and ensure image quality;The square PDMS substrate improves the system’s portability,resistance to environmental interference,and makes the zoom system easier to install and commission.2.Considering the zoom ratio,imaging quality of the zoom system and the resolution when it is used to measure the refractive index of liquids,the system structure is simulated and optimized by optical software ZEMAX,and the parameters of the cylindrical lens system are determined.When the refractive index of the liquid injected in the liquid core of the cylindrical lens imaging system changes from 1.3330to 1.5530,the back focal length f_bof the system can be continuously and smoothly changed from 52.292mm to 4.972mm.The root mean square Y-direction radius of the defocused spot of the lens system is always less than 5μm over the entire zoom range.3.The manufacturing and assembly tolerances of the components of the cylindrical lens zoom system were analyzed,and the symmetrical cylindrical lens and biconvex cylindrical lens were processed,and the assembly and optical path of the PDMS-based miniature liquid-core cylindrical lens system were completed independently.The optical systems have been used to measure refractive index of common liquids,the accuracy of refractive index measurement is better than0.0002RIU for liquids with refractive index less than 1.5530,and better than0.0001RIU for liquids with refractive index between 1.3330 and 1.4312,which is better than Abbe’s refractometer.