Low-Threshold-Voltage and Electrically Switchable Polarization-Selective Scattering Mode Liquid Crystal Light Shutters

Low-threshold-voltage (V(th)) and electrically switchable, polarization-selective scattering mode light shutters (PSMLSs) using polymer-dispersed liquid crystals (PDLCs) are demonstrated in this work. The optimized weight ratio of the nematic liquid crystals (LCs) to the adopted monomer (NBA107, Norland Optics) in the low-V(th) PDLCs based on NBA107 is 7:3, [7:3]-PDLCs(NBA107). The properties of the low-V(th) PDLCs(NBA107), such as light-scattering performance, initial transmission, V(th), and droplet size were investigated. Experiment results show that the surface anchoring (threshold-voltage) of NBA107 is weaker (lower) than or equal to that of the common NOA65. The cost is that the response time of the proposed PDLCs(NBA107) is relatively long. A method to reduce the decay time, which can be applied to all other PDLC devices, will be elucidated. In addition to the low V(th) of the proposed PDLCs(NBA107), the operation voltage (~6 V(rms)) to approach the maximum transmission is relatively low in a 7 μm-thick PDLCs(NBA107) cell. Moreover, the polarization-selective light-scattering performances of the proposed PSMLSs based on the [7:3]-PDLCs(NBA107), mainly driven by in-plane and vertical fields, are also demonstrated.