A Study of Optical Properties of an Electric Tunable-Focusing Liquid Crystal Lens with a Built-in Polymeric Layer
|Keywords:||液晶;液晶透鏡;聚合物薄膜;Liquid crystal;Liquid crystal lens;Polymeric film|
We have developed an electric tunable-focusing liquid crystal (LC) lens with a built-in polymeric layer. The operating principle of such a LC lens is that a built-in polymeric layer with a spatially distribution of dielectric permittivity helps generating an inhomogeneous electric field to the LC layer and then the LC directors are reoriented by the electric fields to form the lens-like phase profile. The main advantage of such a LC lens is low driving voltage. However, the tunable focusing range is small and the optical properties have not been studied yet. In this study, we analyzed the optical properties of the LC lens. We discussed the reasons why the focusing range is small, and also proposed solutions to improve it. After analyzing and studying, we found out that the main limitation causing small tunable focusing range is that LC the directors in the center of the aperture and at the edge of the aperture moves simultaneously and then results in small difference of refractive indexes when a homogeneous electric field applies to LC layer. To overcome this, we proposed a gradient polymer network liquid crystal (PNLC) with a special design to increase the difference of refractive index, and proved the idea by the experiments. The potential application of the LC lens with a built-in polymeric layer is electrically tunable focusing eye-wears, imaging systems in portable devices and pico-projection systems.
|Appears in Collections:||Thesis|