Compensation for color mura on displays by reducing degree of polarization

In displays that use low-cost polymer films such as poly(ethylene terephthalate) (PET) as polarizer protective films, a color mura is caused by a slight amount of birefringence of the polymer film. To address the color mura, this study utilizes a random depolarization film (RDF), which randomly depolarizes light by birefringent dopant particles. We demonstrated that the color mura of a liquid-crystal display with a PET film was compensated by layering an RDF on the PET film. This compensation effect became greater as a degree of polarization of the light transmitted through the RDF decreased. This suggests that the depolarization by the RDF, which reduces the intensity difference between P- and S-waves, contributes to realizing real-color displays even if the low-cost polymer film with a slight amount of birefringence is used in the displays.