光轴可移动圆形液晶透镜  

Circular Liquid Crystal Lens with Shiftable Optical Axes

作　　者：冯文斌 刘志强 叶茂 Feng Wenbin;Liu Zhiqiang;Ye Mao(School of Optoelectronic Science and Engineering,University of Electronic Science and Technology of China,Chengdu 611731,Sichuan,China)

机构地区：[1]电子科技大学光电科学与工程学院,四川成都611731

出　　处：《光学学报》2024年第11期205-214,共10页Acta Optica Sinica

摘　　要：提出了一种光轴可移动的圆形液晶透镜。该透镜包含两个分别处于上下基板的电极:其中一个是离散同心圆电极,用于产生抛物面电压分布;另一个是梳状电极,用于产生线性的电压分布。每个电极施加两个驱动电压,通过控制4个驱动电压实现抛物面电压分布中心位置的移动,从而实现透镜光轴的移动。文中详细地介绍了该透镜的工作原理以及驱动方式,给出了光轴位置坐标与4个驱动电压之间的解析表达式。实验上,通过光刻法加工了对应的电极结构,并制作了孔径为2 mm、液晶层厚度为50μm的液晶透镜。实验结果表明,当透镜的光轴可移动范围在-0.5~0.5 mm时,光焦度可调节的范围是-4.1~4.1 D。该透镜能在光轴移动过程中保持良好的透镜状态,而且光轴移动的误差小于0.01 mm。Objective The liquid crystal(LC)lens,initially introduced by Sato in 1979,is a versatile device that enables the adjustment of focal lengths and optical axis positions without the need for mechanical movement,with applications across various fields.Under numerous scenarios,the optical axial shift in the LC lens yields effects akin to physical lens movement for facilitating functionalities such as optical stabilization,super-resolution imaging,extended depth of field,data storage,laser scanning,and optical trapping.The earliest design for an LC lens with a shiftable optical axis involved segmenting hole-patterned electrodes into multiple sub-electrodes.Optical axis shift is realized by adjusting the voltage applied to each sub-electrode.However,LC lenses relying on hole-patterned electrodes often encounter challenges,including high driving voltages,small aperture sizes,and significant aberrations.Maintaining optimal optical characteristics during optical axis shifting is also confronted with difficulties.An alternative method for achieving optical axis shift is the LC modal lens,which generates a gradient voltage distribution using a high-resistance film,thereby reducing the driving voltage to a few volts.By adopting specific driving methods,the optical axis of a modal lens can shift within the aperture range while theoretically preserving optimal optical characteristics.However,modal lenses constantly face challenges related to stability and uniformity in high-resistance films.Thus,we aim to propose a novel LC lens with a shiftable optical axis to overcome the limitations of current technologies.Methods The phase distribution of a traditional LC lens follows a rotationally symmetric parabolic pattern,with the corresponding voltage distribution containing only quadratic terms.Meanwhile,a linear term should be introduced into the voltage distribution expression to achieve an optical axis shift.We introduce an LC lens with a shiftable optical axis by incorporating a comb-shaped electrode capable of generating a line

关 键 词：光学器件 液晶器件 透镜 光轴 

分 类 号：O435.1[机械工程—光学工程]