A liquid crystal display device includes a backlight unit and a liquid crystal display panel disposed on the backlight unit, wherein the backlight unit includes a light source unit and a plurality of optical sheets, wherein an optical sheet closest to the liquid crystal display panel among the plurality of optical sheets is a polarizing optical sheet and includes a base film and an optical pattern disposed on a surface of the base film, wherein at least one of the base film and the optical pattern includes an aligned organic fluorescent material.