Fabrication of electrically controllable microlens array using a birefringent bilayer

Abstract

Electrically switchable microlens array is demonstrated using a stacking system of UV curable polymer, liquid crystalline polymer (LCP) and liquid crystal (LC) layers. The birefringent LCP provides the incident beam focusing ability of polymer microlens structure as well as the LC aligning property. By engaging external voltage to the device, we can obtain fine dynamic characteristics of the focus switching from the polarization tuning ability of twisted nematic LC layer on the flat boundary condition and the light focusing role of polymer microlens structure, separately. The measured focal characteristics are well matched to the calculated ones and arrayed focused spots are easily switched by applying external voltage. This active microlens array is expected to play a critical role in the various photonic systems such as optical switches, beam modulators and 3-D imaging units.