Study On Aberration Optimization And Driving Integration For Liquid Lens With Large Zoom Range

As a new type of adaptive optical element,liquid lens makes up for many defects of traditional solid lens.It has many advantages,such as simple structure,flexible zoom and various driving modes,and has been widely paid attention by researchers.However,in practical application,the liquid lens still has some problems,such as small zoom ability and low integration,and it is difficult to maintain good dynamic optical performance in the process of zoom.In this paper,the existing problems of liquid lens technology are deeply studied.Firstly,a novel multi-aberration optimization method for thin film liquid lens is proposed.In order to change the traditional scheme of constant thickness film,non-constant thickness thin film design of plane-convex structure is introduced,in which one end of the film is a plane and the other end is a curved surface with a specific surface type.A set of optimization design process of non-equal thickness thin film structure was developed,and the optimal initial structure of non-equal thickness thin film was optimized by combining mechanical and optical simulation.By changing the mechanical deformation characteristics of the film,the liquid lens could always maintain good optical performance within the required zoom range.For non-uniform thickness thin film design,the surface has an initial focal length when facing the outer space,which leads to a limited range of structural aberration optimization.Then an improved liquid lens model is proposed.The curved end face of the thin film is placed towards the liquid cavity,and the optical liquid matching the refractive index of the thin film is used,so that the initial shape of the liquid lens is equivalent to the flat plate,the initial focal length is infinite,and the aberration optimization range of the liquid lens is greatly improved.In addition,in the liquid lens structure designed in this paper,the driving ring is used to extrude the outer area of the film,and the principle of hydraulic conduction is used to make the light passing area in the center of the film deform to realize the zoom function,which effectively improves the integration of the liquid lens and lays a foundation for the miniaturization of the liquid lens in the future.Finally,in order to verify the effectiveness of the method,a liquid lens structure with a diameter of 10 mm and an effective optical aperture of 4 mm is optimized and designed in this paper.Under the action of 0.15 N driving force,the focal length can be adjusted from infinity to 15 mm,and good optical quality can be maintained in the whole zoom range.In this paper,the liquid lens sample was successfully prepared by injection molding method,and its performance was measured systematically.The results show that the transmittance of liquid lens in visible band is above 85%,and the wavefront RMS is less than 80 nm in the zoom range.