Linear Polarizers Prepared Using a Dye-Doped Liquid Crystal through the Coating Approach

Conventional linear polarizers applied for displays are generally prepared through uniaxial stretching or in cells with oriented layers. Herein, linear polarizers were prepared using the dye-doped liquid crystals (LCs) through photopolymerization and the rubbing-oriented poly(ethylene terephthalate) film or the glass plate with aligned SD1 molecules as the substrates. For the good orientation of the LC molecules, the LC mixtures with the I–N–SmA phase transition sequence were prepared. Before photopolymerization, the LC mixtures were cooled from the isotropic state to the nematic phase and subsequently to the SmA phase slowly. Because of the higher ordered structure of the SmA phase, the linear polarizer with the SmA structure exhibits a higher dichroic ratio than that with the nematic one. A patterned linear polarizer suitable for encryption was prepared by controlling the orientation of the SD1 molecules. This work establishes a foundational framework for the large-scale production of linear polarizers by using coating line techniques.