title: Surface profiling of an aspherical liquid lens with a varied thickness membrane.
abstract: Inspired by crystalline lenses in human eyes, liquid lenses have a simple yet elegant working principle, and result in compact optical systems. Recent numerical studies showed that membranes with variable thicknesses could affect the lens profile. However, fabrication and assembly of a liquid lens with an inhomogeneous membrane is difficult. There is also a lack of experimental studies about the changes of a lens profile during deformation. In this paper, we provided a new experimental approach for characterizing the performance of a liquid lens with an inhomogeneous membrane. A 2D axisymmetric lens model was built in finite element analysis software to theoretically study the non-linear deformation behavior of the inhomogeneous membrane. Then we provided a new approach to fabricate inhomogeneous membranes using a pre-machined aluminum mold. An optical coherence tomography (OCT) system was used to dynamically measure the changes of a lens profile without contact. Both simulation and the experiments indicated that the variation of the thickness of the membrane could affect the lens profile in a predictable manner. A negative conic constant was achieved when a plano-concave membrane was adopted in a liquid lens. Larger increments of the thickness of the membrane in the radial direction resulted in a larger contribution of a conic constant to the lens profile. The presented study offers guidance for image-quality analysis and optimization of a liquid-lens-based optical system.
authors.forename: Zengqian
authors.initials: Z
authors.lastname: Ding
authors.forename: Chinhua
authors.initials: C
authors.lastname: Wang
authors.forename: Zhixiong
authors.initials: Z
authors.lastname: Hu
authors.forename: Zhenggang
authors.initials: Z
authors.lastname: Cao
authors.forename: Zhen
authors.initials: Z
authors.lastname: Zhou
authors.forename: Xiangyu
authors.initials: X
authors.lastname: Chen
authors.forename: Hongyu
authors.initials: H
authors.lastname: Chen
authors.forename: Wen
authors.initials: W
authors.lastname: Qiao