Hybrid-Aligned Liquid Crystal Polymers Adhered to the Polarizing Film or Doped with Dichroic Dye for Display Privacy Protection

Abstract

With the widespread use of electronic display devices such as smartphones and tablets, the demand for privacy protection has been steadily increasing. While the traditional shutter privacy films offer a decent antipeeping effect, they suffer from thickness, high costs, and poor frontfacing transparency, affecting the user experience. To solve this problem, and also based on the facts that the linearly polarized light (LPL) emitted by displays and the angular dependence of hybrid-aligned liquid crystal (LC) for LPL, for the first time, here we develop the optical composite films for display antipeeping application based on a polarization-dependent strategy. By combining a hybrid-aligned LC polymer (HLCP) film with a polarizing film (PF), the flexible composite film exhibits excellent narrow viewing angle capability while maintaining high front-facing transmittance, minimizing backlight loss. Furthermore, to achieve a polarizer-free system, we prepared the dichroic dye-doped HLCP film and transferred the consequent film onto optical clear adhesive (OCA). The experimental results confirm that this composite film also exhibits a narrow viewing angle property, which offers an approach for the study of display viewing angle control. These two polarized optical composite films based on HLCP have the potential for practical antipeeping applications in current mainstream display devices.

Recent Advances in Smart Windows Based on Photo‐Responsive Liquid Crystals Featuring Phase Transition

“…For example, adding the photoluminescent (PL) components to form a smart window with PL-active characteristics, introducing a dynamic covalent bond to confer the system with self-healing performance, or incorporating a polarizer to form an optical composite film for display anti-peeping application. [46][47][48][49] Third, to allow smart windows to meet the actual requirements of various scenarios, it is a considerable option to combine light with other stimuli such as electricity, temperature, or humidity into a system to create a photo-/thermal-, photo-/electric-or other multi-regulated systems. Finally, environment-adaptative smart windows based on photo-responsive LCs are on their way to better fit the future development trend.…”