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

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.