Birefringent polyvinyl alcohol layers as retardation components for display devices

Optically birefringent polymers have found utility in numerous applications, especially in liquid crystal displays. This work is focused on inducing molecular ordering in polyvinyl alcohol films in different conditions. The samples were modified by new mixed approaches: drawing, rubbing before drying, rubbing before drying followed by drawing, and combined rubbing, drawing and then parallel scratching. The level of chain alignment in the samples was quantified by birefringence measurements using several experimental techniques, namely interferometry, polarization ellipse approach, channeled spectra and polarized light refractometry. The produced anisotropy was correlated with the sample morphology examined via optical microscopy under crossed polarizers. Optical retardation was found to be larger as the generated birefringence of mechanically deformed polyvinyl alcohol foils was higher. It was found the new proposed approach of ordering polymer sample by combined rubbing, drawing and then scratching is most suitable as retardation layer for compensating light leakage in display devices.

Automated summary

This study focuses on inducing molecular ordering in polyvinyl alcohol films and quantifies the level of chain alignment in the samples using various experimental techniques. The proposed approach of combined rubbing, drawing, and scratching was found to be the most suitable for compensating light leakage as a retardation layer in display devices.