Effects of polarizing film arrangement on the viewing angle of polymer-dispersed liquid crystal films

Abstract

Polymer-dispersed liquid crystal (PDLC) film is an electrically controlled dimming film in which the orientation of the liquid crystal molecules can be changed by applying an electric field. When the liquid crystals are perpendicular to the PDLC film, the film is transparent. Birefringence occurs after light passes through the liquid crystal molecules, resulting in two beams of light with perpendicular vibration directions. Therefore, PDLC film appears hazy when viewed from the side. In this study, a polarizing film was introduced to reduce the side-view haze, and its influence on the haze at different angles and positions was investigated. Experiment results revealed that aligning the PDLC film along the polarizing film’s absorption axis reduced the haze at all angles. When the polarizing film was attached to each side of the PDLC film and the absorption axis angle of the films was 0∘, a wide-viewing-angle PDLC film was obtained; at a 45∘ tilt, the haze only increased by 0.33%, and at 60∘ it maintained a clear field of view. This may be because only light in the same direction as the absorption axis passed through the film, reducing the amount of light that did not match the polymer refractive index.